Merge pull request #56394 from BastiaanOlij/OpenXR_Core4

17 files changed, 7504 insertions, 0 deletions

diff --git a/thirdparty/openxr/src/external/jsoncpp/AUTHORS b/thirdparty/openxr/src/external/jsoncpp/AUTHORS
new file mode 100644
index 0000000000..e1fa0fc3ad
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/AUTHORS
@@ -0,0 +1,115 @@
+Baptiste Lepilleur <blep@users.sourceforge.net>
+
+Aaron Jacobs <aaronjjacobs@gmail.com>
+Aaron Jacobs <jacobsa@google.com>
+Adam Boseley <ABoseley@agjunction.com>
+Adam Boseley <adam.boseley@gmail.com>
+Aleksandr Derbenev <13alexac@gmail.com>
+Alexander Gazarov <DrMetallius@users.noreply.github.com>
+Alexander V. Brezgin <abrezgin@appliedtech.ru>
+Alexandr Brezgin <albrezgin@mail.ru>
+Alexey Kruchinin <alexey@mopals.com>
+Anton Indrawan <anton.indrawan@gmail.com>
+Baptiste Jonglez <git@bitsofnetworks.org>
+Baptiste Lepilleur <baptiste.lepilleur@gmail.com>
+Baruch Siach <baruch@tkos.co.il>
+Ben Boeckel <mathstuf@gmail.com>
+Benjamin Knecht <bknecht@logitech.com>
+Bernd Kuhls <bernd.kuhls@t-online.de>
+Billy Donahue <billydonahue@google.com>
+Braden McDorman <bmcdorman@gmail.com>
+Brandon Myers <bmyers1788@gmail.com>
+Brendan Drew <brendan.drew@daqri.com>
+chason <cxchao802@gmail.com>
+chenguoping <chenguopingdota@163.com>
+Chris Gilling <cgilling@iparadigms.com>
+Christopher Dawes <christopher.dawes.1981@googlemail.com>
+Christopher Dunn <cdunn2001@gmail.com>
+Chuck Atkins <chuck.atkins@kitware.com>
+Cody P Schafer <dev@codyps.com>
+Connor Manning <connor@hobu.co>
+Cory Quammen <cory.quammen@kitware.com>
+Cristóvão B da Cruz e Silva <CrisXed@gmail.com>
+Daniel Krügler <daniel.kruegler@gmail.com>
+Dani-Hub <daniel.kruegler@googlemail.com>
+Dan Liu <gzliudan>
+datadiode <datadiode@users.noreply.github.com>
+datadiode <jochen.neubeck@vodafone.de>
+David Seifert <soap@gentoo.org>
+David West <david-west@idexx.com>
+dawesc <chris.dawes@eftlab.co.uk>
+Devin Jeanpierre <jeanpierreda@google.com>
+Dmitry Marakasov <amdmi3@amdmi3.ru>
+dominicpezzuto <dom@dompezzuto.com>
+Don Milham <dmilham@gmail.com>
+drgler <daniel.kruegler@gmail.com>
+ds283 <D.Seery@sussex.ac.uk>
+Egor Tensin <Egor.Tensin@gmail.com>
+eightnoteight <mr.eightnoteight@gmail.com>
+Evince <baneyue@gmail.com>
+filipjs <filipjs@users.noreply.github.com>
+findblar <ft@finbarr.ca>
+Florian Meier <florian.meier@koalo.de>
+Gaëtan Lehmann <gaetan.lehmann@gmail.com>
+Gaurav <g.gupta@samsung.com>
+Gergely Nagy <ngg@ngg.hu>
+Gida Pataki <gida.pataki@prezi.com>
+I3ck <buckmartin@buckmartin.de>
+Iñaki Baz Castillo <ibc@aliax.net>
+Jacco <jacco@geul.net>
+Jean-Christophe Fillion-Robin <jchris.fillionr@kitware.com>
+Jonas Platte <mail@jonasplatte.de>
+Jordan Bayles <bayles.jordan@gmail.com>
+Jörg Krause <joerg.krause@embedded.rocks>
+Keith Lea <keith@whamcitylights.com>
+Kevin Grant <kbradleygrant@gmail.com>
+Kirill V. Lyadvinsky <jia3ep@gmail.com>
+Kirill V. Lyadvinsky <mail@codeatcpp.com>
+Kobi Gurkan <kobigurk@gmail.com>
+Magnus Bjerke Vik <mbvett@gmail.com>
+Malay Shah <malays@users.sourceforge.net>
+Mara Kim <hacker.root@gmail.com>
+Marek Kotewicz <marek.kotewicz@gmail.com>
+Mark Lakata <mark@lakata.org>
+Mark Zeren <mzeren@vmware.com>
+Martin Buck <buckmartin@buckmartin.de>
+Martyn Gigg <martyn.gigg@gmail.com>
+Mattes D <github@xoft.cz>
+Matthias Loy <matthias.loy@hbm.com>
+Merlyn Morgan-Graham <kavika@gmail.com>
+Michael Shields <mshields@google.com>
+Michał Górny <mgorny@gentoo.org>
+Mike Naberezny <mike@naberezny.com>
+mloy <matthias.loy@googlemail.com>
+Motti <lanzkron@gmail.com>
+nnkur <nnkur@mail.ru>
+Omkar Wagh <owagh@owaghlinux.ny.tower-research.com>
+paulo <paulobrizolara@users.noreply.github.com>
+pavel.pimenov <pavel.pimenov@gmail.com>
+Paweł Bylica <chfast@gmail.com>
+Péricles Lopes Machado <pericles.raskolnikoff@gmail.com>
+Peter Spiess-Knafl <psk@autistici.org>
+pffang <pffang@vip.qq.com>
+Rémi Verschelde <remi@verschelde.fr>
+renu555 <renu.tyagi@samsung.com>
+Robert Dailey <rcdailey@gmail.com>
+Sam Clegg <sbc@chromium.org>
+selaselah <selah@outlook.com>
+Sergiy80 <sil2004@gmail.com>
+sergzub <sergzub@gmail.com>
+Stefan Schweter <stefan@schweter.it>
+Stefano Fiorentino <stefano.fiore84@gmail.com>
+Steffen Kieß <Steffen.Kiess@ipvs.uni-stuttgart.de>
+Steven Hahn <hahnse@ornl.gov>
+Stuart Eichert <stuart@fivemicro.com>
+SuperManitu <supermanitu@gmail.com>
+Techwolf <dring@g33kworld.net>
+Tengiz Sharafiev <btolfa+github@gmail.com>
+Tomasz Maciejewski <tmaciejewsk@gmail.com>
+Vicente Olivert Riera <Vincent.Riera@imgtec.com>
+xiaoyur347 <xiaoyur347@gmail.com>
+ycqiu <429148848@qq.com>
+yiqiju <fred_ju@selinc.com>
+Yu Xiaolei <dreifachstein@gmail.com>
+
+Google Inc.
diff --git a/thirdparty/openxr/src/external/jsoncpp/LICENSE b/thirdparty/openxr/src/external/jsoncpp/LICENSE
new file mode 100644
index 0000000000..c41a1d1c77
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/LICENSE
@@ -0,0 +1,55 @@
+The JsonCpp library's source code, including accompanying documentation,
+tests and demonstration applications, are licensed under the following
+conditions...
+
+Baptiste Lepilleur and The JsonCpp Authors explicitly disclaim copyright in all
+jurisdictions which recognize such a disclaimer. In such jurisdictions,
+this software is released into the Public Domain.
+
+In jurisdictions which do not recognize Public Domain property (e.g. Germany as of
+2010), this software is Copyright (c) 2007-2010 by Baptiste Lepilleur and
+The JsonCpp Authors, and is released under the terms of the MIT License (see below).
+
+In jurisdictions which recognize Public Domain property, the user of this
+software may choose to accept it either as 1) Public Domain, 2) under the
+conditions of the MIT License (see below), or 3) under the terms of dual
+Public Domain/MIT License conditions described here, as they choose.
+
+The MIT License is about as close to Public Domain as a license can get, and is
+described in clear, concise terms at:
+
+   http://en.wikipedia.org/wiki/MIT_License
+
+The full text of the MIT License follows:
+
+========================================================================
+Copyright (c) 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use, copy,
+modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+========================================================================
+(END LICENSE TEXT)
+
+The MIT license is compatible with both the GPL and commercial
+software, affording one all of the rights of Public Domain with the
+minor nuisance of being required to keep the above copyright notice
+and license text in the source code. Note also that by accepting the
+Public Domain "license" you can re-license your copy using whatever
+license you like.
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/allocator.h b/thirdparty/openxr/src/external/jsoncpp/include/json/allocator.h
new file mode 100644
index 0000000000..95ef8a5ec4
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/allocator.h
@@ -0,0 +1,88 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_ALLOCATOR_H_INCLUDED
+#define JSON_ALLOCATOR_H_INCLUDED
+
+#include <cstring>
+#include <memory>
+
+#pragma pack(push, 8)
+
+namespace Json {
+template <typename T> class SecureAllocator {
+public:
+  // Type definitions
+  using value_type = T;
+  using pointer = T*;
+  using const_pointer = const T*;
+  using reference = T&;
+  using const_reference = const T&;
+  using size_type = std::size_t;
+  using difference_type = std::ptrdiff_t;
+
+  /**
+   * Allocate memory for N items using the standard allocator.
+   */
+  pointer allocate(size_type n) {
+    // allocate using "global operator new"
+    return static_cast<pointer>(::operator new(n * sizeof(T)));
+  }
+
+  /**
+   * Release memory which was allocated for N items at pointer P.
+   *
+   * The memory block is filled with zeroes before being released.
+   */
+  void deallocate(pointer p, size_type n) {
+    // memset_s is used because memset may be optimized away by the compiler
+    memset_s(p, n * sizeof(T), 0, n * sizeof(T));
+    // free using "global operator delete"
+    ::operator delete(p);
+  }
+
+  /**
+   * Construct an item in-place at pointer P.
+   */
+  template <typename... Args> void construct(pointer p, Args&&... args) {
+    // construct using "placement new" and "perfect forwarding"
+    ::new (static_cast<void*>(p)) T(std::forward<Args>(args)...);
+  }
+
+  size_type max_size() const { return size_t(-1) / sizeof(T); }
+
+  pointer address(reference x) const { return std::addressof(x); }
+
+  const_pointer address(const_reference x) const { return std::addressof(x); }
+
+  /**
+   * Destroy an item in-place at pointer P.
+   */
+  void destroy(pointer p) {
+    // destroy using "explicit destructor"
+    p->~T();
+  }
+
+  // Boilerplate
+  SecureAllocator() {}
+  template <typename U> SecureAllocator(const SecureAllocator<U>&) {}
+  template <typename U> struct rebind { using other = SecureAllocator<U>; };
+};
+
+template <typename T, typename U>
+bool operator==(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+  return true;
+}
+
+template <typename T, typename U>
+bool operator!=(const SecureAllocator<T>&, const SecureAllocator<U>&) {
+  return false;
+}
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#endif // JSON_ALLOCATOR_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/assertions.h b/thirdparty/openxr/src/external/jsoncpp/include/json/assertions.h
new file mode 100644
index 0000000000..666fa7f542
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/assertions.h
@@ -0,0 +1,61 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_ASSERTIONS_H_INCLUDED
+#define JSON_ASSERTIONS_H_INCLUDED
+
+#include <cstdlib>
+#include <sstream>
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "config.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+
+/** It should not be possible for a maliciously designed file to
+ *  cause an abort() or seg-fault, so these macros are used only
+ *  for pre-condition violations and internal logic errors.
+ */
+#if JSON_USE_EXCEPTION
+
+// @todo <= add detail about condition in exception
+#define JSON_ASSERT(condition)                                                 \
+  do {                                                                         \
+    if (!(condition)) {                                                        \
+      Json::throwLogicError("assert json failed");                             \
+    }                                                                          \
+  } while (0)
+
+#define JSON_FAIL_MESSAGE(message)                                             \
+  do {                                                                         \
+    OStringStream oss;                                                         \
+    oss << message;                                                            \
+    Json::throwLogicError(oss.str());                                          \
+    abort();                                                                   \
+  } while (0)
+
+#else // JSON_USE_EXCEPTION
+
+#define JSON_ASSERT(condition) assert(condition)
+
+// The call to assert() will show the failure message in debug builds. In
+// release builds we abort, for a core-dump or debugger.
+#define JSON_FAIL_MESSAGE(message)                                             \
+  {                                                                            \
+    OStringStream oss;                                                         \
+    oss << message;                                                            \
+    assert(false && oss.str().c_str());                                        \
+    abort();                                                                   \
+  }
+
+#endif
+
+#define JSON_ASSERT_MESSAGE(condition, message)                                \
+  do {                                                                         \
+    if (!(condition)) {                                                        \
+      JSON_FAIL_MESSAGE(message);                                              \
+    }                                                                          \
+  } while (0)
+
+#endif // JSON_ASSERTIONS_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/config.h b/thirdparty/openxr/src/external/jsoncpp/include/json/config.h
new file mode 100644
index 0000000000..6359273a22
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/config.h
@@ -0,0 +1,150 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_CONFIG_H_INCLUDED
+#define JSON_CONFIG_H_INCLUDED
+#include <cstddef>
+#include <cstdint>
+#include <istream>
+#include <memory>
+#include <ostream>
+#include <sstream>
+#include <string>
+#include <type_traits>
+
+// If non-zero, the library uses exceptions to report bad input instead of C
+// assertion macros. The default is to use exceptions.
+#ifndef JSON_USE_EXCEPTION
+#define JSON_USE_EXCEPTION 1
+#endif
+
+// Temporary, tracked for removal with issue #982.
+#ifndef JSON_USE_NULLREF
+#define JSON_USE_NULLREF 1
+#endif
+
+/// If defined, indicates that the source file is amalgamated
+/// to prevent private header inclusion.
+/// Remarks: it is automatically defined in the generated amalgamated header.
+// #define JSON_IS_AMALGAMATION
+
+// Export macros for DLL visibility
+#if defined(JSON_DLL_BUILD)
+#if defined(_MSC_VER) || defined(__MINGW32__)
+#define JSON_API __declspec(dllexport)
+#define JSONCPP_DISABLE_DLL_INTERFACE_WARNING
+#elif defined(__GNUC__) || defined(__clang__)
+#define JSON_API __attribute__((visibility("default")))
+#endif // if defined(_MSC_VER)
+
+#elif defined(JSON_DLL)
+#if defined(_MSC_VER) || defined(__MINGW32__)
+#define JSON_API __declspec(dllimport)
+#define JSONCPP_DISABLE_DLL_INTERFACE_WARNING
+#endif // if defined(_MSC_VER)
+#endif // ifdef JSON_DLL_BUILD
+
+#if !defined(JSON_API)
+#define JSON_API
+#endif
+
+#if defined(_MSC_VER) && _MSC_VER < 1800
+#error                                                                         \
+    "ERROR:  Visual Studio 12 (2013) with _MSC_VER=1800 is the oldest supported compiler with sufficient C++11 capabilities"
+#endif
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+// As recommended at
+// https://stackoverflow.com/questions/2915672/snprintf-and-visual-studio-2010
+extern JSON_API int msvc_pre1900_c99_snprintf(char* outBuf, size_t size,
+                                              const char* format, ...);
+#define jsoncpp_snprintf msvc_pre1900_c99_snprintf
+#else
+#define jsoncpp_snprintf std::snprintf
+#endif
+
+// If JSON_NO_INT64 is defined, then Json only support C++ "int" type for
+// integer
+// Storages, and 64 bits integer support is disabled.
+// #define JSON_NO_INT64 1
+
+// JSONCPP_OVERRIDE is maintained for backwards compatibility of external tools.
+// C++11 should be used directly in JSONCPP.
+#define JSONCPP_OVERRIDE override
+
+#ifdef __clang__
+#if __has_extension(attribute_deprecated_with_message)
+#define JSONCPP_DEPRECATED(message) __attribute__((deprecated(message)))
+#endif
+#elif defined(__GNUC__) // not clang (gcc comes later since clang emulates gcc)
+#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
+#define JSONCPP_DEPRECATED(message) __attribute__((deprecated(message)))
+#elif (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
+#define JSONCPP_DEPRECATED(message) __attribute__((__deprecated__))
+#endif                  // GNUC version
+#elif defined(_MSC_VER) // MSVC (after clang because clang on Windows emulates
+                        // MSVC)
+#define JSONCPP_DEPRECATED(message) __declspec(deprecated(message))
+#endif // __clang__ || __GNUC__ || _MSC_VER
+
+#if !defined(JSONCPP_DEPRECATED)
+#define JSONCPP_DEPRECATED(message)
+#endif // if !defined(JSONCPP_DEPRECATED)
+
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ >= 6))
+#define JSON_USE_INT64_DOUBLE_CONVERSION 1
+#endif
+
+#if !defined(JSON_IS_AMALGAMATION)
+
+#include "allocator.h"
+#include "version.h"
+
+#endif // if !defined(JSON_IS_AMALGAMATION)
+
+namespace Json {
+using Int = int;
+using UInt = unsigned int;
+#if defined(JSON_NO_INT64)
+using LargestInt = int;
+using LargestUInt = unsigned int;
+#undef JSON_HAS_INT64
+#else                 // if defined(JSON_NO_INT64)
+// For Microsoft Visual use specific types as long long is not supported
+#if defined(_MSC_VER) // Microsoft Visual Studio
+using Int64 = __int64;
+using UInt64 = unsigned __int64;
+#else                 // if defined(_MSC_VER) // Other platforms, use long long
+using Int64 = int64_t;
+using UInt64 = uint64_t;
+#endif                // if defined(_MSC_VER)
+using LargestInt = Int64;
+using LargestUInt = UInt64;
+#define JSON_HAS_INT64
+#endif // if defined(JSON_NO_INT64)
+
+template <typename T>
+using Allocator =
+    typename std::conditional<JSONCPP_USING_SECURE_MEMORY, SecureAllocator<T>,
+                              std::allocator<T>>::type;
+using String = std::basic_string<char, std::char_traits<char>, Allocator<char>>;
+using IStringStream =
+    std::basic_istringstream<String::value_type, String::traits_type,
+                             String::allocator_type>;
+using OStringStream =
+    std::basic_ostringstream<String::value_type, String::traits_type,
+                             String::allocator_type>;
+using IStream = std::istream;
+using OStream = std::ostream;
+} // namespace Json
+
+// Legacy names (formerly macros).
+using JSONCPP_STRING = Json::String;
+using JSONCPP_ISTRINGSTREAM = Json::IStringStream;
+using JSONCPP_OSTRINGSTREAM = Json::OStringStream;
+using JSONCPP_ISTREAM = Json::IStream;
+using JSONCPP_OSTREAM = Json::OStream;
+
+#endif // JSON_CONFIG_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/forwards.h b/thirdparty/openxr/src/external/jsoncpp/include/json/forwards.h
new file mode 100644
index 0000000000..affe33a7f9
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/forwards.h
@@ -0,0 +1,43 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_FORWARDS_H_INCLUDED
+#define JSON_FORWARDS_H_INCLUDED
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "config.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+
+namespace Json {
+
+// writer.h
+class StreamWriter;
+class StreamWriterBuilder;
+class Writer;
+class FastWriter;
+class StyledWriter;
+class StyledStreamWriter;
+
+// reader.h
+class Reader;
+class CharReader;
+class CharReaderBuilder;
+
+// json_features.h
+class Features;
+
+// value.h
+using ArrayIndex = unsigned int;
+class StaticString;
+class Path;
+class PathArgument;
+class Value;
+class ValueIteratorBase;
+class ValueIterator;
+class ValueConstIterator;
+
+} // namespace Json
+
+#endif // JSON_FORWARDS_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/json.h b/thirdparty/openxr/src/external/jsoncpp/include/json/json.h
new file mode 100644
index 0000000000..5c776a1609
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/json.h
@@ -0,0 +1,15 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_JSON_H_INCLUDED
+#define JSON_JSON_H_INCLUDED
+
+#include "config.h"
+#include "json_features.h"
+#include "reader.h"
+#include "value.h"
+#include "writer.h"
+
+#endif // JSON_JSON_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/json_features.h b/thirdparty/openxr/src/external/jsoncpp/include/json/json_features.h
new file mode 100644
index 0000000000..7c7e9f5de1
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/json_features.h
@@ -0,0 +1,61 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_FEATURES_H_INCLUDED
+#define JSON_FEATURES_H_INCLUDED
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "forwards.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+
+#pragma pack(push, 8)
+
+namespace Json {
+
+/** \brief Configuration passed to reader and writer.
+ * This configuration object can be used to force the Reader or Writer
+ * to behave in a standard conforming way.
+ */
+class JSON_API Features {
+public:
+  /** \brief A configuration that allows all features and assumes all strings
+   * are UTF-8.
+   * - C & C++ comments are allowed
+   * - Root object can be any JSON value
+   * - Assumes Value strings are encoded in UTF-8
+   */
+  static Features all();
+
+  /** \brief A configuration that is strictly compatible with the JSON
+   * specification.
+   * - Comments are forbidden.
+   * - Root object must be either an array or an object value.
+   * - Assumes Value strings are encoded in UTF-8
+   */
+  static Features strictMode();
+
+  /** \brief Initialize the configuration like JsonConfig::allFeatures;
+   */
+  Features();
+
+  /// \c true if comments are allowed. Default: \c true.
+  bool allowComments_{true};
+
+  /// \c true if root must be either an array or an object value. Default: \c
+  /// false.
+  bool strictRoot_{false};
+
+  /// \c true if dropped null placeholders are allowed. Default: \c false.
+  bool allowDroppedNullPlaceholders_{false};
+
+  /// \c true if numeric object key are allowed. Default: \c false.
+  bool allowNumericKeys_{false};
+};
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#endif // JSON_FEATURES_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/reader.h b/thirdparty/openxr/src/external/jsoncpp/include/json/reader.h
new file mode 100644
index 0000000000..be0d7676ab
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/reader.h
@@ -0,0 +1,405 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_READER_H_INCLUDED
+#define JSON_READER_H_INCLUDED
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "json_features.h"
+#include "value.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+#include <deque>
+#include <iosfwd>
+#include <istream>
+#include <stack>
+#include <string>
+
+// Disable warning C4251: <data member>: <type> needs to have dll-interface to
+// be used by...
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+#pragma warning(push)
+#pragma warning(disable : 4251)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+#pragma pack(push, 8)
+
+namespace Json {
+
+/** \brief Unserialize a <a HREF="http://www.json.org">JSON</a> document into a
+ * Value.
+ *
+ * \deprecated Use CharReader and CharReaderBuilder.
+ */
+
+class JSON_API Reader {
+public:
+  using Char = char;
+  using Location = const Char*;
+
+  /** \brief An error tagged with where in the JSON text it was encountered.
+   *
+   * The offsets give the [start, limit) range of bytes within the text. Note
+   * that this is bytes, not codepoints.
+   */
+  struct StructuredError {
+    ptrdiff_t offset_start;
+    ptrdiff_t offset_limit;
+    String message;
+  };
+
+  /** \brief Constructs a Reader allowing all features for parsing.
+    * \deprecated Use CharReader and CharReaderBuilder.
+   */
+  Reader();
+
+  /** \brief Constructs a Reader allowing the specified feature set for parsing.
+    * \deprecated Use CharReader and CharReaderBuilder.
+   */
+  Reader(const Features& features);
+
+  /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
+   * document.
+   *
+   * \param      document        UTF-8 encoded string containing the document
+   *                             to read.
+   * \param[out] root            Contains the root value of the document if it
+   *                             was successfully parsed.
+   * \param      collectComments \c true to collect comment and allow writing
+   *                             them back during serialization, \c false to
+   *                             discard comments.  This parameter is ignored
+   *                             if Features::allowComments_ is \c false.
+   * \return \c true if the document was successfully parsed, \c false if an
+   * error occurred.
+   */
+  bool parse(const std::string& document, Value& root,
+             bool collectComments = true);
+
+  /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
+   * document.
+   *
+   * \param      beginDoc        Pointer on the beginning of the UTF-8 encoded
+   *                             string of the document to read.
+   * \param      endDoc          Pointer on the end of the UTF-8 encoded string
+   *                             of the document to read.  Must be >= beginDoc.
+   * \param[out] root            Contains the root value of the document if it
+   *                             was successfully parsed.
+   * \param      collectComments \c true to collect comment and allow writing
+   *                             them back during serialization, \c false to
+   *                             discard comments.  This parameter is ignored
+   *                             if Features::allowComments_ is \c false.
+   * \return \c true if the document was successfully parsed, \c false if an
+   * error occurred.
+   */
+  bool parse(const char* beginDoc, const char* endDoc, Value& root,
+             bool collectComments = true);
+
+  /// \brief Parse from input stream.
+  /// \see Json::operator>>(std::istream&, Json::Value&).
+  bool parse(IStream& is, Value& root, bool collectComments = true);
+
+  /** \brief Returns a user friendly string that list errors in the parsed
+   * document.
+   *
+   * \return Formatted error message with the list of errors with their
+   * location in the parsed document. An empty string is returned if no error
+   * occurred during parsing.
+   * \deprecated Use getFormattedErrorMessages() instead (typo fix).
+   */
+  JSONCPP_DEPRECATED("Use getFormattedErrorMessages() instead.")
+  String getFormatedErrorMessages() const;
+
+  /** \brief Returns a user friendly string that list errors in the parsed
+   * document.
+   *
+   * \return Formatted error message with the list of errors with their
+   * location in the parsed document. An empty string is returned if no error
+   * occurred during parsing.
+   */
+  String getFormattedErrorMessages() const;
+
+  /** \brief Returns a vector of structured errors encountered while parsing.
+   *
+   * \return A (possibly empty) vector of StructuredError objects. Currently
+   * only one error can be returned, but the caller should tolerate multiple
+   * errors.  This can occur if the parser recovers from a non-fatal parse
+   * error and then encounters additional errors.
+   */
+  std::vector<StructuredError> getStructuredErrors() const;
+
+  /** \brief Add a semantic error message.
+   *
+   * \param value   JSON Value location associated with the error
+   * \param message The error message.
+   * \return \c true if the error was successfully added, \c false if the Value
+   * offset exceeds the document size.
+   */
+  bool pushError(const Value& value, const String& message);
+
+  /** \brief Add a semantic error message with extra context.
+   *
+   * \param value   JSON Value location associated with the error
+   * \param message The error message.
+   * \param extra   Additional JSON Value location to contextualize the error
+   * \return \c true if the error was successfully added, \c false if either
+   * Value offset exceeds the document size.
+   */
+  bool pushError(const Value& value, const String& message, const Value& extra);
+
+  /** \brief Return whether there are any errors.
+   *
+   * \return \c true if there are no errors to report \c false if errors have
+   * occurred.
+   */
+  bool good() const;
+
+private:
+  enum TokenType {
+    tokenEndOfStream = 0,
+    tokenObjectBegin,
+    tokenObjectEnd,
+    tokenArrayBegin,
+    tokenArrayEnd,
+    tokenString,
+    tokenNumber,
+    tokenTrue,
+    tokenFalse,
+    tokenNull,
+    tokenArraySeparator,
+    tokenMemberSeparator,
+    tokenComment,
+    tokenError
+  };
+
+  class Token {
+  public:
+    TokenType type_;
+    Location start_;
+    Location end_;
+  };
+
+  class ErrorInfo {
+  public:
+    Token token_;
+    String message_;
+    Location extra_;
+  };
+
+  using Errors = std::deque<ErrorInfo>;
+
+  bool readToken(Token& token);
+  void skipSpaces();
+  bool match(const Char* pattern, int patternLength);
+  bool readComment();
+  bool readCStyleComment();
+  bool readCppStyleComment();
+  bool readString();
+  void readNumber();
+  bool readValue();
+  bool readObject(Token& token);
+  bool readArray(Token& token);
+  bool decodeNumber(Token& token);
+  bool decodeNumber(Token& token, Value& decoded);
+  bool decodeString(Token& token);
+  bool decodeString(Token& token, String& decoded);
+  bool decodeDouble(Token& token);
+  bool decodeDouble(Token& token, Value& decoded);
+  bool decodeUnicodeCodePoint(Token& token, Location& current, Location end,
+                              unsigned int& unicode);
+  bool decodeUnicodeEscapeSequence(Token& token, Location& current,
+                                   Location end, unsigned int& unicode);
+  bool addError(const String& message, Token& token, Location extra = nullptr);
+  bool recoverFromError(TokenType skipUntilToken);
+  bool addErrorAndRecover(const String& message, Token& token,
+                          TokenType skipUntilToken);
+  void skipUntilSpace();
+  Value& currentValue();
+  Char getNextChar();
+  void getLocationLineAndColumn(Location location, int& line,
+                                int& column) const;
+  String getLocationLineAndColumn(Location location) const;
+  void addComment(Location begin, Location end, CommentPlacement placement);
+  void skipCommentTokens(Token& token);
+
+  static bool containsNewLine(Location begin, Location end);
+  static String normalizeEOL(Location begin, Location end);
+
+  using Nodes = std::stack<Value*>;
+  Nodes nodes_;
+  Errors errors_;
+  String document_;
+  Location begin_{};
+  Location end_{};
+  Location current_{};
+  Location lastValueEnd_{};
+  Value* lastValue_{};
+  String commentsBefore_;
+  Features features_;
+  bool collectComments_{};
+}; // Reader
+
+/** Interface for reading JSON from a char array.
+ */
+class JSON_API CharReader {
+public:
+  virtual ~CharReader() = default;
+  /** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
+   * document. The document must be a UTF-8 encoded string containing the
+   * document to read.
+   *
+   * \param      beginDoc Pointer on the beginning of the UTF-8 encoded string
+   *                      of the document to read.
+   * \param      endDoc   Pointer on the end of the UTF-8 encoded string of the
+   *                      document to read. Must be >= beginDoc.
+   * \param[out] root     Contains the root value of the document if it was
+   *                      successfully parsed.
+   * \param[out] errs     Formatted error messages (if not NULL) a user
+   *                      friendly string that lists errors in the parsed
+   *                      document.
+   * \return \c true if the document was successfully parsed, \c false if an
+   * error occurred.
+   */
+  virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
+                     String* errs) = 0;
+
+  class JSON_API Factory {
+  public:
+    virtual ~Factory() = default;
+    /** \brief Allocate a CharReader via operator new().
+     * \throw std::exception if something goes wrong (e.g. invalid settings)
+     */
+    virtual CharReader* newCharReader() const = 0;
+  }; // Factory
+};   // CharReader
+
+/** \brief Build a CharReader implementation.
+ *
+ * Usage:
+ *   \code
+ *   using namespace Json;
+ *   CharReaderBuilder builder;
+ *   builder["collectComments"] = false;
+ *   Value value;
+ *   String errs;
+ *   bool ok = parseFromStream(builder, std::cin, &value, &errs);
+ *   \endcode
+ */
+class JSON_API CharReaderBuilder : public CharReader::Factory {
+public:
+  // Note: We use a Json::Value so that we can add data-members to this class
+  // without a major version bump.
+  /** Configuration of this builder.
+   * These are case-sensitive.
+   * Available settings (case-sensitive):
+   * - `"collectComments": false or true`
+   *   - true to collect comment and allow writing them back during
+   *     serialization, false to discard comments.  This parameter is ignored
+   *     if allowComments is false.
+   * - `"allowComments": false or true`
+   *   - true if comments are allowed.
+   * - `"allowTrailingCommas": false or true`
+   *   - true if trailing commas in objects and arrays are allowed.
+   * - `"strictRoot": false or true`
+   *   - true if root must be either an array or an object value
+   * - `"allowDroppedNullPlaceholders": false or true`
+   *   - true if dropped null placeholders are allowed. (See
+   *     StreamWriterBuilder.)
+   * - `"allowNumericKeys": false or true`
+   *   - true if numeric object keys are allowed.
+   * - `"allowSingleQuotes": false or true`
+   *   - true if '' are allowed for strings (both keys and values)
+   * - `"stackLimit": integer`
+   *   - Exceeding stackLimit (recursive depth of `readValue()`) will cause an
+   *     exception.
+   *   - This is a security issue (seg-faults caused by deeply nested JSON), so
+   *     the default is low.
+   * - `"failIfExtra": false or true`
+   *   - If true, `parse()` returns false when extra non-whitespace trails the
+   *     JSON value in the input string.
+   * - `"rejectDupKeys": false or true`
+   *   - If true, `parse()` returns false when a key is duplicated within an
+   *     object.
+   * - `"allowSpecialFloats": false or true`
+   *   - If true, special float values (NaNs and infinities) are allowed and
+   *     their values are lossfree restorable.
+   * - `"skipBom": false or true`
+   *   - If true, if the input starts with the Unicode byte order mark (BOM),
+   *     it is skipped.
+   *
+   * You can examine 'settings_` yourself to see the defaults. You can also
+   * write and read them just like any JSON Value.
+   * \sa setDefaults()
+   */
+  Json::Value settings_;
+
+  CharReaderBuilder();
+  ~CharReaderBuilder() override;
+
+  CharReader* newCharReader() const override;
+
+  /** \return true if 'settings' are legal and consistent;
+   *   otherwise, indicate bad settings via 'invalid'.
+   */
+  bool validate(Json::Value* invalid) const;
+
+  /** A simple way to update a specific setting.
+   */
+  Value& operator[](const String& key);
+
+  /** Called by ctor, but you can use this to reset settings_.
+   * \pre 'settings' != NULL (but Json::null is fine)
+   * \remark Defaults:
+   * \snippet src/lib_json/json_reader.cpp CharReaderBuilderDefaults
+   */
+  static void setDefaults(Json::Value* settings);
+  /** Same as old Features::strictMode().
+   * \pre 'settings' != NULL (but Json::null is fine)
+   * \remark Defaults:
+   * \snippet src/lib_json/json_reader.cpp CharReaderBuilderStrictMode
+   */
+  static void strictMode(Json::Value* settings);
+};
+
+/** Consume entire stream and use its begin/end.
+ * Someday we might have a real StreamReader, but for now this
+ * is convenient.
+ */
+bool JSON_API parseFromStream(CharReader::Factory const&, IStream&, Value* root,
+                              String* errs);
+
+/** \brief Read from 'sin' into 'root'.
+ *
+ * Always keep comments from the input JSON.
+ *
+ * This can be used to read a file into a particular sub-object.
+ * For example:
+ *   \code
+ *   Json::Value root;
+ *   cin >> root["dir"]["file"];
+ *   cout << root;
+ *   \endcode
+ * Result:
+ * \verbatim
+ * {
+ * "dir": {
+ *    "file": {
+ *    // The input stream JSON would be nested here.
+ *    }
+ * }
+ * }
+ * \endverbatim
+ * \throw std::exception on parse error.
+ * \see Json::operator<<()
+ */
+JSON_API IStream& operator>>(IStream&, Value&);
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+#pragma warning(pop)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+#endif // JSON_READER_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/value.h b/thirdparty/openxr/src/external/jsoncpp/include/json/value.h
new file mode 100644
index 0000000000..0edeb050ca
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/value.h
@@ -0,0 +1,935 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_H_INCLUDED
+#define JSON_H_INCLUDED
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "forwards.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+
+// Conditional NORETURN attribute on the throw functions would:
+// a) suppress false positives from static code analysis
+// b) possibly improve optimization opportunities.
+#if !defined(JSONCPP_NORETURN)
+#if defined(_MSC_VER) && _MSC_VER == 1800
+#define JSONCPP_NORETURN __declspec(noreturn)
+#else
+#define JSONCPP_NORETURN [[noreturn]]
+#endif
+#endif
+
+// Support for '= delete' with template declarations was a late addition
+// to the c++11 standard and is rejected by clang 3.8 and Apple clang 8.2
+// even though these declare themselves to be c++11 compilers.
+#if !defined(JSONCPP_TEMPLATE_DELETE)
+#if defined(__clang__) && defined(__apple_build_version__)
+#if __apple_build_version__ <= 8000042
+#define JSONCPP_TEMPLATE_DELETE
+#endif
+#elif defined(__clang__)
+#if __clang_major__ == 3 && __clang_minor__ <= 8
+#define JSONCPP_TEMPLATE_DELETE
+#endif
+#endif
+#if !defined(JSONCPP_TEMPLATE_DELETE)
+#define JSONCPP_TEMPLATE_DELETE = delete
+#endif
+#endif
+
+#include <array>
+#include <exception>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+// Disable warning C4251: <data member>: <type> needs to have dll-interface to
+// be used by...
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+#pragma warning(push)
+#pragma warning(disable : 4251 4275)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+#pragma pack(push, 8)
+
+/** \brief JSON (JavaScript Object Notation).
+ */
+namespace Json {
+
+#if JSON_USE_EXCEPTION
+/** Base class for all exceptions we throw.
+ *
+ * We use nothing but these internally. Of course, STL can throw others.
+ */
+class JSON_API Exception : public std::exception {
+public:
+  Exception(String msg);
+  ~Exception() noexcept override;
+  char const* what() const noexcept override;
+
+protected:
+  String msg_;
+};
+
+/** Exceptions which the user cannot easily avoid.
+ *
+ * E.g. out-of-memory (when we use malloc), stack-overflow, malicious input
+ *
+ * \remark derived from Json::Exception
+ */
+class JSON_API RuntimeError : public Exception {
+public:
+  RuntimeError(String const& msg);
+};
+
+/** Exceptions thrown by JSON_ASSERT/JSON_FAIL macros.
+ *
+ * These are precondition-violations (user bugs) and internal errors (our bugs).
+ *
+ * \remark derived from Json::Exception
+ */
+class JSON_API LogicError : public Exception {
+public:
+  LogicError(String const& msg);
+};
+#endif
+
+/// used internally
+JSONCPP_NORETURN void throwRuntimeError(String const& msg);
+/// used internally
+JSONCPP_NORETURN void throwLogicError(String const& msg);
+
+/** \brief Type of the value held by a Value object.
+ */
+enum ValueType {
+  nullValue = 0, ///< 'null' value
+  intValue,      ///< signed integer value
+  uintValue,     ///< unsigned integer value
+  realValue,     ///< double value
+  stringValue,   ///< UTF-8 string value
+  booleanValue,  ///< bool value
+  arrayValue,    ///< array value (ordered list)
+  objectValue    ///< object value (collection of name/value pairs).
+};
+
+enum CommentPlacement {
+  commentBefore = 0,      ///< a comment placed on the line before a value
+  commentAfterOnSameLine, ///< a comment just after a value on the same line
+  commentAfter, ///< a comment on the line after a value (only make sense for
+  /// root value)
+  numberOfCommentPlacement
+};
+
+/** \brief Type of precision for formatting of real values.
+ */
+enum PrecisionType {
+  significantDigits = 0, ///< we set max number of significant digits in string
+  decimalPlaces          ///< we set max number of digits after "." in string
+};
+
+/** \brief Lightweight wrapper to tag static string.
+ *
+ * Value constructor and objectValue member assignment takes advantage of the
+ * StaticString and avoid the cost of string duplication when storing the
+ * string or the member name.
+ *
+ * Example of usage:
+ * \code
+ * Json::Value aValue( StaticString("some text") );
+ * Json::Value object;
+ * static const StaticString code("code");
+ * object[code] = 1234;
+ * \endcode
+ */
+class JSON_API StaticString {
+public:
+  explicit StaticString(const char* czstring) : c_str_(czstring) {}
+
+  operator const char*() const { return c_str_; }
+
+  const char* c_str() const { return c_str_; }
+
+private:
+  const char* c_str_;
+};
+
+/** \brief Represents a <a HREF="http://www.json.org">JSON</a> value.
+ *
+ * This class is a discriminated union wrapper that can represents a:
+ * - signed integer [range: Value::minInt - Value::maxInt]
+ * - unsigned integer (range: 0 - Value::maxUInt)
+ * - double
+ * - UTF-8 string
+ * - boolean
+ * - 'null'
+ * - an ordered list of Value
+ * - collection of name/value pairs (javascript object)
+ *
+ * The type of the held value is represented by a #ValueType and
+ * can be obtained using type().
+ *
+ * Values of an #objectValue or #arrayValue can be accessed using operator[]()
+ * methods.
+ * Non-const methods will automatically create the a #nullValue element
+ * if it does not exist.
+ * The sequence of an #arrayValue will be automatically resized and initialized
+ * with #nullValue. resize() can be used to enlarge or truncate an #arrayValue.
+ *
+ * The get() methods can be used to obtain default value in the case the
+ * required element does not exist.
+ *
+ * It is possible to iterate over the list of member keys of an object using
+ * the getMemberNames() method.
+ *
+ * \note #Value string-length fit in size_t, but keys must be < 2^30.
+ * (The reason is an implementation detail.) A #CharReader will raise an
+ * exception if a bound is exceeded to avoid security holes in your app,
+ * but the Value API does *not* check bounds. That is the responsibility
+ * of the caller.
+ */
+class JSON_API Value {
+  friend class ValueIteratorBase;
+
+public:
+  using Members = std::vector<String>;
+  using iterator = ValueIterator;
+  using const_iterator = ValueConstIterator;
+  using UInt = Json::UInt;
+  using Int = Json::Int;
+#if defined(JSON_HAS_INT64)
+  using UInt64 = Json::UInt64;
+  using Int64 = Json::Int64;
+#endif // defined(JSON_HAS_INT64)
+  using LargestInt = Json::LargestInt;
+  using LargestUInt = Json::LargestUInt;
+  using ArrayIndex = Json::ArrayIndex;
+
+  // Required for boost integration, e. g. BOOST_TEST
+  using value_type = std::string;
+
+#if JSON_USE_NULLREF
+  // Binary compatibility kludges, do not use.
+  static const Value& null;
+  static const Value& nullRef;
+#endif
+
+  // null and nullRef are deprecated, use this instead.
+  static Value const& nullSingleton();
+
+  /// Minimum signed integer value that can be stored in a Json::Value.
+  static constexpr LargestInt minLargestInt =
+      LargestInt(~(LargestUInt(-1) / 2));
+  /// Maximum signed integer value that can be stored in a Json::Value.
+  static constexpr LargestInt maxLargestInt = LargestInt(LargestUInt(-1) / 2);
+  /// Maximum unsigned integer value that can be stored in a Json::Value.
+  static constexpr LargestUInt maxLargestUInt = LargestUInt(-1);
+
+  /// Minimum signed int value that can be stored in a Json::Value.
+  static constexpr Int minInt = Int(~(UInt(-1) / 2));
+  /// Maximum signed int value that can be stored in a Json::Value.
+  static constexpr Int maxInt = Int(UInt(-1) / 2);
+  /// Maximum unsigned int value that can be stored in a Json::Value.
+  static constexpr UInt maxUInt = UInt(-1);
+
+#if defined(JSON_HAS_INT64)
+  /// Minimum signed 64 bits int value that can be stored in a Json::Value.
+  static constexpr Int64 minInt64 = Int64(~(UInt64(-1) / 2));
+  /// Maximum signed 64 bits int value that can be stored in a Json::Value.
+  static constexpr Int64 maxInt64 = Int64(UInt64(-1) / 2);
+  /// Maximum unsigned 64 bits int value that can be stored in a Json::Value.
+  static constexpr UInt64 maxUInt64 = UInt64(-1);
+#endif // defined(JSON_HAS_INT64)
+  /// Default precision for real value for string representation.
+  static constexpr UInt defaultRealPrecision = 17;
+  // The constant is hard-coded because some compiler have trouble
+  // converting Value::maxUInt64 to a double correctly (AIX/xlC).
+  // Assumes that UInt64 is a 64 bits integer.
+  static constexpr double maxUInt64AsDouble = 18446744073709551615.0;
+// Workaround for bug in the NVIDIAs CUDA 9.1 nvcc compiler
+// when using gcc and clang backend compilers.  CZString
+// cannot be defined as private.  See issue #486
+#ifdef __NVCC__
+public:
+#else
+private:
+#endif
+#ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
+  class CZString {
+  public:
+    enum DuplicationPolicy { noDuplication = 0, duplicate, duplicateOnCopy };
+    CZString(ArrayIndex index);
+    CZString(char const* str, unsigned length, DuplicationPolicy allocate);
+    CZString(CZString const& other);
+    CZString(CZString&& other) noexcept;
+    ~CZString();
+    CZString& operator=(const CZString& other);
+    CZString& operator=(CZString&& other) noexcept;
+
+    bool operator<(CZString const& other) const;
+    bool operator==(CZString const& other) const;
+    ArrayIndex index() const;
+    // const char* c_str() const; ///< \deprecated
+    char const* data() const;
+    unsigned length() const;
+    bool isStaticString() const;
+
+  private:
+    void swap(CZString& other);
+
+    struct StringStorage {
+      unsigned policy_ : 2;
+      unsigned length_ : 30; // 1GB max
+    };
+
+    char const* cstr_; // actually, a prefixed string, unless policy is noDup
+    union {
+      ArrayIndex index_;
+      StringStorage storage_;
+    };
+  };
+
+public:
+  typedef std::map<CZString, Value> ObjectValues;
+#endif // ifndef JSONCPP_DOC_EXCLUDE_IMPLEMENTATION
+
+public:
+  /**
+   * \brief Create a default Value of the given type.
+   *
+   * This is a very useful constructor.
+   * To create an empty array, pass arrayValue.
+   * To create an empty object, pass objectValue.
+   * Another Value can then be set to this one by assignment.
+   * This is useful since clear() and resize() will not alter types.
+   *
+   * Examples:
+   *   \code
+   *   Json::Value null_value; // null
+   *   Json::Value arr_value(Json::arrayValue); // []
+   *   Json::Value obj_value(Json::objectValue); // {}
+   *   \endcode
+   */
+  Value(ValueType type = nullValue);
+  Value(Int value);
+  Value(UInt value);
+#if defined(JSON_HAS_INT64)
+  Value(Int64 value);
+  Value(UInt64 value);
+#endif // if defined(JSON_HAS_INT64)
+  Value(double value);
+  Value(const char* value); ///< Copy til first 0. (NULL causes to seg-fault.)
+  Value(const char* begin, const char* end); ///< Copy all, incl zeroes.
+  /**
+   * \brief Constructs a value from a static string.
+   *
+   * Like other value string constructor but do not duplicate the string for
+   * internal storage. The given string must remain alive after the call to
+   * this constructor.
+   *
+   * \note This works only for null-terminated strings. (We cannot change the
+   * size of this class, so we have nowhere to store the length, which might be
+   * computed later for various operations.)
+   *
+   * Example of usage:
+   *   \code
+   *   static StaticString foo("some text");
+   *   Json::Value aValue(foo);
+   *   \endcode
+   */
+  Value(const StaticString& value);
+  Value(const String& value);
+  Value(bool value);
+  Value(std::nullptr_t ptr) = delete;
+  Value(const Value& other);
+  Value(Value&& other) noexcept;
+  ~Value();
+
+  /// \note Overwrite existing comments. To preserve comments, use
+  /// #swapPayload().
+  Value& operator=(const Value& other);
+  Value& operator=(Value&& other) noexcept;
+
+  /// Swap everything.
+  void swap(Value& other);
+  /// Swap values but leave comments and source offsets in place.
+  void swapPayload(Value& other);
+
+  /// copy everything.
+  void copy(const Value& other);
+  /// copy values but leave comments and source offsets in place.
+  void copyPayload(const Value& other);
+
+  ValueType type() const;
+
+  /// Compare payload only, not comments etc.
+  bool operator<(const Value& other) const;
+  bool operator<=(const Value& other) const;
+  bool operator>=(const Value& other) const;
+  bool operator>(const Value& other) const;
+  bool operator==(const Value& other) const;
+  bool operator!=(const Value& other) const;
+  int compare(const Value& other) const;
+
+  const char* asCString() const; ///< Embedded zeroes could cause you trouble!
+#if JSONCPP_USING_SECURE_MEMORY
+  unsigned getCStringLength() const; // Allows you to understand the length of
+                                     // the CString
+#endif
+  String asString() const; ///< Embedded zeroes are possible.
+  /** Get raw char* of string-value.
+   *  \return false if !string. (Seg-fault if str or end are NULL.)
+   */
+  bool getString(char const** begin, char const** end) const;
+  Int asInt() const;
+  UInt asUInt() const;
+#if defined(JSON_HAS_INT64)
+  Int64 asInt64() const;
+  UInt64 asUInt64() const;
+#endif // if defined(JSON_HAS_INT64)
+  LargestInt asLargestInt() const;
+  LargestUInt asLargestUInt() const;
+  float asFloat() const;
+  double asDouble() const;
+  bool asBool() const;
+
+  bool isNull() const;
+  bool isBool() const;
+  bool isInt() const;
+  bool isInt64() const;
+  bool isUInt() const;
+  bool isUInt64() const;
+  bool isIntegral() const;
+  bool isDouble() const;
+  bool isNumeric() const;
+  bool isString() const;
+  bool isArray() const;
+  bool isObject() const;
+
+  /// The `as<T>` and `is<T>` member function templates and specializations.
+  template <typename T> T as() const JSONCPP_TEMPLATE_DELETE;
+  template <typename T> bool is() const JSONCPP_TEMPLATE_DELETE;
+
+  bool isConvertibleTo(ValueType other) const;
+
+  /// Number of values in array or object
+  ArrayIndex size() const;
+
+  /// \brief Return true if empty array, empty object, or null;
+  /// otherwise, false.
+  bool empty() const;
+
+  /// Return !isNull()
+  explicit operator bool() const;
+
+  /// Remove all object members and array elements.
+  /// \pre type() is arrayValue, objectValue, or nullValue
+  /// \post type() is unchanged
+  void clear();
+
+  /// Resize the array to newSize elements.
+  /// New elements are initialized to null.
+  /// May only be called on nullValue or arrayValue.
+  /// \pre type() is arrayValue or nullValue
+  /// \post type() is arrayValue
+  void resize(ArrayIndex newSize);
+
+  //@{
+  /// Access an array element (zero based index). If the array contains less
+  /// than index element, then null value are inserted in the array so that
+  /// its size is index+1.
+  /// (You may need to say 'value[0u]' to get your compiler to distinguish
+  /// this from the operator[] which takes a string.)
+  Value& operator[](ArrayIndex index);
+  Value& operator[](int index);
+  //@}
+
+  //@{
+  /// Access an array element (zero based index).
+  /// (You may need to say 'value[0u]' to get your compiler to distinguish
+  /// this from the operator[] which takes a string.)
+  const Value& operator[](ArrayIndex index) const;
+  const Value& operator[](int index) const;
+  //@}
+
+  /// If the array contains at least index+1 elements, returns the element
+  /// value, otherwise returns defaultValue.
+  Value get(ArrayIndex index, const Value& defaultValue) const;
+  /// Return true if index < size().
+  bool isValidIndex(ArrayIndex index) const;
+  /// \brief Append value to array at the end.
+  ///
+  /// Equivalent to jsonvalue[jsonvalue.size()] = value;
+  Value& append(const Value& value);
+  Value& append(Value&& value);
+
+  /// \brief Insert value in array at specific index
+  bool insert(ArrayIndex index, const Value& newValue);
+  bool insert(ArrayIndex index, Value&& newValue);
+
+  /// Access an object value by name, create a null member if it does not exist.
+  /// \note Because of our implementation, keys are limited to 2^30 -1 chars.
+  /// Exceeding that will cause an exception.
+  Value& operator[](const char* key);
+  /// Access an object value by name, returns null if there is no member with
+  /// that name.
+  const Value& operator[](const char* key) const;
+  /// Access an object value by name, create a null member if it does not exist.
+  /// \param key may contain embedded nulls.
+  Value& operator[](const String& key);
+  /// Access an object value by name, returns null if there is no member with
+  /// that name.
+  /// \param key may contain embedded nulls.
+  const Value& operator[](const String& key) const;
+  /** \brief Access an object value by name, create a null member if it does not
+   * exist.
+   *
+   * If the object has no entry for that name, then the member name used to
+   * store the new entry is not duplicated.
+   * Example of use:
+   *   \code
+   *   Json::Value object;
+   *   static const StaticString code("code");
+   *   object[code] = 1234;
+   *   \endcode
+   */
+  Value& operator[](const StaticString& key);
+  /// Return the member named key if it exist, defaultValue otherwise.
+  /// \note deep copy
+  Value get(const char* key, const Value& defaultValue) const;
+  /// Return the member named key if it exist, defaultValue otherwise.
+  /// \note deep copy
+  /// \note key may contain embedded nulls.
+  Value get(const char* begin, const char* end,
+            const Value& defaultValue) const;
+  /// Return the member named key if it exist, defaultValue otherwise.
+  /// \note deep copy
+  /// \param key may contain embedded nulls.
+  Value get(const String& key, const Value& defaultValue) const;
+  /// Most general and efficient version of isMember()const, get()const,
+  /// and operator[]const
+  /// \note As stated elsewhere, behavior is undefined if (end-begin) >= 2^30
+  Value const* find(char const* begin, char const* end) const;
+  /// Most general and efficient version of object-mutators.
+  /// \note As stated elsewhere, behavior is undefined if (end-begin) >= 2^30
+  /// \return non-zero, but JSON_ASSERT if this is neither object nor nullValue.
+  Value* demand(char const* begin, char const* end);
+  /// \brief Remove and return the named member.
+  ///
+  /// Do nothing if it did not exist.
+  /// \pre type() is objectValue or nullValue
+  /// \post type() is unchanged
+  void removeMember(const char* key);
+  /// Same as removeMember(const char*)
+  /// \param key may contain embedded nulls.
+  void removeMember(const String& key);
+  /// Same as removeMember(const char* begin, const char* end, Value* removed),
+  /// but 'key' is null-terminated.
+  bool removeMember(const char* key, Value* removed);
+  /** \brief Remove the named map member.
+   *
+   *  Update 'removed' iff removed.
+   *  \param key may contain embedded nulls.
+   *  \return true iff removed (no exceptions)
+   */
+  bool removeMember(String const& key, Value* removed);
+  /// Same as removeMember(String const& key, Value* removed)
+  bool removeMember(const char* begin, const char* end, Value* removed);
+  /** \brief Remove the indexed array element.
+   *
+   *  O(n) expensive operations.
+   *  Update 'removed' iff removed.
+   *  \return true if removed (no exceptions)
+   */
+  bool removeIndex(ArrayIndex index, Value* removed);
+
+  /// Return true if the object has a member named key.
+  /// \note 'key' must be null-terminated.
+  bool isMember(const char* key) const;
+  /// Return true if the object has a member named key.
+  /// \param key may contain embedded nulls.
+  bool isMember(const String& key) const;
+  /// Same as isMember(String const& key)const
+  bool isMember(const char* begin, const char* end) const;
+
+  /// \brief Return a list of the member names.
+  ///
+  /// If null, return an empty list.
+  /// \pre type() is objectValue or nullValue
+  /// \post if type() was nullValue, it remains nullValue
+  Members getMemberNames() const;
+
+  /// \deprecated Always pass len.
+  JSONCPP_DEPRECATED("Use setComment(String const&) instead.")
+  void setComment(const char* comment, CommentPlacement placement) {
+    setComment(String(comment, strlen(comment)), placement);
+  }
+  /// Comments must be //... or /* ... */
+  void setComment(const char* comment, size_t len, CommentPlacement placement) {
+    setComment(String(comment, len), placement);
+  }
+  /// Comments must be //... or /* ... */
+  void setComment(String comment, CommentPlacement placement);
+  bool hasComment(CommentPlacement placement) const;
+  /// Include delimiters and embedded newlines.
+  String getComment(CommentPlacement placement) const;
+
+  String toStyledString() const;
+
+  const_iterator begin() const;
+  const_iterator end() const;
+
+  iterator begin();
+  iterator end();
+
+  // Accessors for the [start, limit) range of bytes within the JSON text from
+  // which this value was parsed, if any.
+  void setOffsetStart(ptrdiff_t start);
+  void setOffsetLimit(ptrdiff_t limit);
+  ptrdiff_t getOffsetStart() const;
+  ptrdiff_t getOffsetLimit() const;
+
+private:
+  void setType(ValueType v) {
+    bits_.value_type_ = static_cast<unsigned char>(v);
+  }
+  bool isAllocated() const { return bits_.allocated_; }
+  void setIsAllocated(bool v) { bits_.allocated_ = v; }
+
+  void initBasic(ValueType type, bool allocated = false);
+  void dupPayload(const Value& other);
+  void releasePayload();
+  void dupMeta(const Value& other);
+
+  Value& resolveReference(const char* key);
+  Value& resolveReference(const char* key, const char* end);
+
+  // struct MemberNamesTransform
+  //{
+  //   typedef const char *result_type;
+  //   const char *operator()( const CZString &name ) const
+  //   {
+  //      return name.c_str();
+  //   }
+  //};
+
+  union ValueHolder {
+    LargestInt int_;
+    LargestUInt uint_;
+    double real_;
+    bool bool_;
+    char* string_; // if allocated_, ptr to { unsigned, char[] }.
+    ObjectValues* map_;
+  } value_;
+
+  struct {
+    // Really a ValueType, but types should agree for bitfield packing.
+    unsigned int value_type_ : 8;
+    // Unless allocated_, string_ must be null-terminated.
+    unsigned int allocated_ : 1;
+  } bits_;
+
+  class Comments {
+  public:
+    Comments() = default;
+    Comments(const Comments& that);
+    Comments(Comments&& that) noexcept;
+    Comments& operator=(const Comments& that);
+    Comments& operator=(Comments&& that) noexcept;
+    bool has(CommentPlacement slot) const;
+    String get(CommentPlacement slot) const;
+    void set(CommentPlacement slot, String comment);
+
+  private:
+    using Array = std::array<String, numberOfCommentPlacement>;
+    std::unique_ptr<Array> ptr_;
+  };
+  Comments comments_;
+
+  // [start, limit) byte offsets in the source JSON text from which this Value
+  // was extracted.
+  ptrdiff_t start_;
+  ptrdiff_t limit_;
+};
+
+template <> inline bool Value::as<bool>() const { return asBool(); }
+template <> inline bool Value::is<bool>() const { return isBool(); }
+
+template <> inline Int Value::as<Int>() const { return asInt(); }
+template <> inline bool Value::is<Int>() const { return isInt(); }
+
+template <> inline UInt Value::as<UInt>() const { return asUInt(); }
+template <> inline bool Value::is<UInt>() const { return isUInt(); }
+
+#if defined(JSON_HAS_INT64)
+template <> inline Int64 Value::as<Int64>() const { return asInt64(); }
+template <> inline bool Value::is<Int64>() const { return isInt64(); }
+
+template <> inline UInt64 Value::as<UInt64>() const { return asUInt64(); }
+template <> inline bool Value::is<UInt64>() const { return isUInt64(); }
+#endif
+
+template <> inline double Value::as<double>() const { return asDouble(); }
+template <> inline bool Value::is<double>() const { return isDouble(); }
+
+template <> inline String Value::as<String>() const { return asString(); }
+template <> inline bool Value::is<String>() const { return isString(); }
+
+/// These `as` specializations are type conversions, and do not have a
+/// corresponding `is`.
+template <> inline float Value::as<float>() const { return asFloat(); }
+template <> inline const char* Value::as<const char*>() const {
+  return asCString();
+}
+
+/** \brief Experimental and untested: represents an element of the "path" to
+ * access a node.
+ */
+class JSON_API PathArgument {
+public:
+  friend class Path;
+
+  PathArgument();
+  PathArgument(ArrayIndex index);
+  PathArgument(const char* key);
+  PathArgument(String key);
+
+private:
+  enum Kind { kindNone = 0, kindIndex, kindKey };
+  String key_;
+  ArrayIndex index_{};
+  Kind kind_{kindNone};
+};
+
+/** \brief Experimental and untested: represents a "path" to access a node.
+ *
+ * Syntax:
+ * - "." => root node
+ * - ".[n]" => elements at index 'n' of root node (an array value)
+ * - ".name" => member named 'name' of root node (an object value)
+ * - ".name1.name2.name3"
+ * - ".[0][1][2].name1[3]"
+ * - ".%" => member name is provided as parameter
+ * - ".[%]" => index is provided as parameter
+ */
+class JSON_API Path {
+public:
+  Path(const String& path, const PathArgument& a1 = PathArgument(),
+       const PathArgument& a2 = PathArgument(),
+       const PathArgument& a3 = PathArgument(),
+       const PathArgument& a4 = PathArgument(),
+       const PathArgument& a5 = PathArgument());
+
+  const Value& resolve(const Value& root) const;
+  Value resolve(const Value& root, const Value& defaultValue) const;
+  /// Creates the "path" to access the specified node and returns a reference on
+  /// the node.
+  Value& make(Value& root) const;
+
+private:
+  using InArgs = std::vector<const PathArgument*>;
+  using Args = std::vector<PathArgument>;
+
+  void makePath(const String& path, const InArgs& in);
+  void addPathInArg(const String& path, const InArgs& in,
+                    InArgs::const_iterator& itInArg, PathArgument::Kind kind);
+  static void invalidPath(const String& path, int location);
+
+  Args args_;
+};
+
+/** \brief base class for Value iterators.
+ *
+ */
+class JSON_API ValueIteratorBase {
+public:
+  using iterator_category = std::bidirectional_iterator_tag;
+  using size_t = unsigned int;
+  using difference_type = int;
+  using SelfType = ValueIteratorBase;
+
+  bool operator==(const SelfType& other) const { return isEqual(other); }
+
+  bool operator!=(const SelfType& other) const { return !isEqual(other); }
+
+  difference_type operator-(const SelfType& other) const {
+    return other.computeDistance(*this);
+  }
+
+  /// Return either the index or the member name of the referenced value as a
+  /// Value.
+  Value key() const;
+
+  /// Return the index of the referenced Value, or -1 if it is not an
+  /// arrayValue.
+  UInt index() const;
+
+  /// Return the member name of the referenced Value, or "" if it is not an
+  /// objectValue.
+  /// \note Avoid `c_str()` on result, as embedded zeroes are possible.
+  String name() const;
+
+  /// Return the member name of the referenced Value. "" if it is not an
+  /// objectValue.
+  /// \deprecated This cannot be used for UTF-8 strings, since there can be
+  /// embedded nulls.
+  JSONCPP_DEPRECATED("Use `key = name();` instead.")
+  char const* memberName() const;
+  /// Return the member name of the referenced Value, or NULL if it is not an
+  /// objectValue.
+  /// \note Better version than memberName(). Allows embedded nulls.
+  char const* memberName(char const** end) const;
+
+protected:
+  /*! Internal utility functions to assist with implementing
+   *   other iterator functions. The const and non-const versions
+   *   of the "deref" protected methods expose the protected
+   *   current_ member variable in a way that can often be
+   *   optimized away by the compiler.
+   */
+  const Value& deref() const;
+  Value& deref();
+
+  void increment();
+
+  void decrement();
+
+  difference_type computeDistance(const SelfType& other) const;
+
+  bool isEqual(const SelfType& other) const;
+
+  void copy(const SelfType& other);
+
+private:
+  Value::ObjectValues::iterator current_;
+  // Indicates that iterator is for a null value.
+  bool isNull_{true};
+
+public:
+  // For some reason, BORLAND needs these at the end, rather
+  // than earlier. No idea why.
+  ValueIteratorBase();
+  explicit ValueIteratorBase(const Value::ObjectValues::iterator& current);
+};
+
+/** \brief const iterator for object and array value.
+ *
+ */
+class JSON_API ValueConstIterator : public ValueIteratorBase {
+  friend class Value;
+
+public:
+  using value_type = const Value;
+  // typedef unsigned int size_t;
+  // typedef int difference_type;
+  using reference = const Value&;
+  using pointer = const Value*;
+  using SelfType = ValueConstIterator;
+
+  ValueConstIterator();
+  ValueConstIterator(ValueIterator const& other);
+
+private:
+  /*! \internal Use by Value to create an iterator.
+   */
+  explicit ValueConstIterator(const Value::ObjectValues::iterator& current);
+
+public:
+  SelfType& operator=(const ValueIteratorBase& other);
+
+  SelfType operator++(int) {
+    SelfType temp(*this);
+    ++*this;
+    return temp;
+  }
+
+  SelfType operator--(int) {
+    SelfType temp(*this);
+    --*this;
+    return temp;
+  }
+
+  SelfType& operator--() {
+    decrement();
+    return *this;
+  }
+
+  SelfType& operator++() {
+    increment();
+    return *this;
+  }
+
+  reference operator*() const { return deref(); }
+
+  pointer operator->() const { return &deref(); }
+};
+
+/** \brief Iterator for object and array value.
+ */
+class JSON_API ValueIterator : public ValueIteratorBase {
+  friend class Value;
+
+public:
+  using value_type = Value;
+  using size_t = unsigned int;
+  using difference_type = int;
+  using reference = Value&;
+  using pointer = Value*;
+  using SelfType = ValueIterator;
+
+  ValueIterator();
+  explicit ValueIterator(const ValueConstIterator& other);
+  ValueIterator(const ValueIterator& other);
+
+private:
+  /*! \internal Use by Value to create an iterator.
+   */
+  explicit ValueIterator(const Value::ObjectValues::iterator& current);
+
+public:
+  SelfType& operator=(const SelfType& other);
+
+  SelfType operator++(int) {
+    SelfType temp(*this);
+    ++*this;
+    return temp;
+  }
+
+  SelfType operator--(int) {
+    SelfType temp(*this);
+    --*this;
+    return temp;
+  }
+
+  SelfType& operator--() {
+    decrement();
+    return *this;
+  }
+
+  SelfType& operator++() {
+    increment();
+    return *this;
+  }
+
+  /*! The return value of non-const iterators can be
+   *  changed, so the these functions are not const
+   *  because the returned references/pointers can be used
+   *  to change state of the base class.
+   */
+  reference operator*() const { return const_cast<reference>(deref()); }
+  pointer operator->() const { return const_cast<pointer>(&deref()); }
+};
+
+inline void swap(Value& a, Value& b) { a.swap(b); }
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+#pragma warning(pop)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+#endif // JSON_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/version.h b/thirdparty/openxr/src/external/jsoncpp/include/json/version.h
new file mode 100644
index 0000000000..e931d0383e
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/version.h
@@ -0,0 +1,28 @@
+#ifndef JSON_VERSION_H_INCLUDED
+#define JSON_VERSION_H_INCLUDED
+
+// Note: version must be updated in three places when doing a release. This
+// annoying process ensures that amalgamate, CMake, and meson all report the
+// correct version.
+// 1. /meson.build
+// 2. /include/json/version.h
+// 3. /CMakeLists.txt
+// IMPORTANT: also update the SOVERSION!!
+
+#define JSONCPP_VERSION_STRING "1.9.5"
+#define JSONCPP_VERSION_MAJOR 1
+#define JSONCPP_VERSION_MINOR 9
+#define JSONCPP_VERSION_PATCH 5
+#define JSONCPP_VERSION_QUALIFIER
+#define JSONCPP_VERSION_HEXA                                                   \
+  ((JSONCPP_VERSION_MAJOR << 24) | (JSONCPP_VERSION_MINOR << 16) |             \
+   (JSONCPP_VERSION_PATCH << 8))
+
+#ifdef JSONCPP_USING_SECURE_MEMORY
+#undef JSONCPP_USING_SECURE_MEMORY
+#endif
+#define JSONCPP_USING_SECURE_MEMORY 0
+// If non-zero, the library zeroes any memory that it has allocated before
+// it frees its memory.
+
+#endif // JSON_VERSION_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/include/json/writer.h b/thirdparty/openxr/src/external/jsoncpp/include/json/writer.h
new file mode 100644
index 0000000000..88a3b12e9d
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/include/json/writer.h
@@ -0,0 +1,369 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef JSON_WRITER_H_INCLUDED
+#define JSON_WRITER_H_INCLUDED
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "value.h"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+#include <ostream>
+#include <string>
+#include <vector>
+
+// Disable warning C4251: <data member>: <type> needs to have dll-interface to
+// be used by...
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING) && defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4251)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+#pragma pack(push, 8)
+
+namespace Json {
+
+class Value;
+
+/**
+ *
+ * Usage:
+ *  \code
+ *  using namespace Json;
+ *  void writeToStdout(StreamWriter::Factory const& factory, Value const& value)
+ * { std::unique_ptr<StreamWriter> const writer( factory.newStreamWriter());
+ *    writer->write(value, &std::cout);
+ *    std::cout << std::endl;  // add lf and flush
+ *  }
+ *  \endcode
+ */
+class JSON_API StreamWriter {
+protected:
+  OStream* sout_; // not owned; will not delete
+public:
+  StreamWriter();
+  virtual ~StreamWriter();
+  /** Write Value into document as configured in sub-class.
+   *   Do not take ownership of sout, but maintain a reference during function.
+   *   \pre sout != NULL
+   *   \return zero on success (For now, we always return zero, so check the
+   *   stream instead.) \throw std::exception possibly, depending on
+   * configuration
+   */
+  virtual int write(Value const& root, OStream* sout) = 0;
+
+  /** \brief A simple abstract factory.
+   */
+  class JSON_API Factory {
+  public:
+    virtual ~Factory();
+    /** \brief Allocate a CharReader via operator new().
+     * \throw std::exception if something goes wrong (e.g. invalid settings)
+     */
+    virtual StreamWriter* newStreamWriter() const = 0;
+  }; // Factory
+};   // StreamWriter
+
+/** \brief Write into stringstream, then return string, for convenience.
+ * A StreamWriter will be created from the factory, used, and then deleted.
+ */
+String JSON_API writeString(StreamWriter::Factory const& factory,
+                            Value const& root);
+
+/** \brief Build a StreamWriter implementation.
+
+* Usage:
+*   \code
+*   using namespace Json;
+*   Value value = ...;
+*   StreamWriterBuilder builder;
+*   builder["commentStyle"] = "None";
+*   builder["indentation"] = "   ";  // or whatever you like
+*   std::unique_ptr<Json::StreamWriter> writer(
+*      builder.newStreamWriter());
+*   writer->write(value, &std::cout);
+*   std::cout << std::endl;  // add lf and flush
+*   \endcode
+*/
+class JSON_API StreamWriterBuilder : public StreamWriter::Factory {
+public:
+  // Note: We use a Json::Value so that we can add data-members to this class
+  // without a major version bump.
+  /** Configuration of this builder.
+   *  Available settings (case-sensitive):
+   *  - "commentStyle": "None" or "All"
+   *  - "indentation":  "<anything>".
+   *  - Setting this to an empty string also omits newline characters.
+   *  - "enableYAMLCompatibility": false or true
+   *  - slightly change the whitespace around colons
+   *  - "dropNullPlaceholders": false or true
+   *  - Drop the "null" string from the writer's output for nullValues.
+   *    Strictly speaking, this is not valid JSON. But when the output is being
+   *    fed to a browser's JavaScript, it makes for smaller output and the
+   *    browser can handle the output just fine.
+   *  - "useSpecialFloats": false or true
+   *  - If true, outputs non-finite floating point values in the following way:
+   *    NaN values as "NaN", positive infinity as "Infinity", and negative
+   *  infinity as "-Infinity".
+   *  - "precision": int
+   *  - Number of precision digits for formatting of real values.
+   *  - "precisionType": "significant"(default) or "decimal"
+   *  - Type of precision for formatting of real values.
+   *  - "emitUTF8": false or true
+   *  - If true, outputs raw UTF8 strings instead of escaping them.
+
+   *  You can examine 'settings_` yourself
+   *  to see the defaults. You can also write and read them just like any
+   *  JSON Value.
+   *  \sa setDefaults()
+   */
+  Json::Value settings_;
+
+  StreamWriterBuilder();
+  ~StreamWriterBuilder() override;
+
+  /**
+   * \throw std::exception if something goes wrong (e.g. invalid settings)
+   */
+  StreamWriter* newStreamWriter() const override;
+
+  /** \return true if 'settings' are legal and consistent;
+   *   otherwise, indicate bad settings via 'invalid'.
+   */
+  bool validate(Json::Value* invalid) const;
+  /** A simple way to update a specific setting.
+   */
+  Value& operator[](const String& key);
+
+  /** Called by ctor, but you can use this to reset settings_.
+   * \pre 'settings' != NULL (but Json::null is fine)
+   * \remark Defaults:
+   * \snippet src/lib_json/json_writer.cpp StreamWriterBuilderDefaults
+   */
+  static void setDefaults(Json::Value* settings);
+};
+
+/** \brief Abstract class for writers.
+ * \deprecated Use StreamWriter. (And really, this is an implementation detail.)
+ */
+class JSON_API Writer {
+public:
+  virtual ~Writer();
+
+  virtual String write(const Value& root) = 0;
+};
+
+/** \brief Outputs a Value in <a HREF="http://www.json.org">JSON</a> format
+ *without formatting (not human friendly).
+ *
+ * The JSON document is written in a single line. It is not intended for 'human'
+ *consumption,
+ * but may be useful to support feature such as RPC where bandwidth is limited.
+ * \sa Reader, Value
+ * \deprecated Use StreamWriterBuilder.
+ */
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4996) // Deriving from deprecated class
+#endif
+class JSON_API FastWriter
+    : public Writer {
+public:
+  FastWriter();
+  ~FastWriter() override = default;
+
+  void enableYAMLCompatibility();
+
+  /** \brief Drop the "null" string from the writer's output for nullValues.
+   * Strictly speaking, this is not valid JSON. But when the output is being
+   * fed to a browser's JavaScript, it makes for smaller output and the
+   * browser can handle the output just fine.
+   */
+  void dropNullPlaceholders();
+
+  void omitEndingLineFeed();
+
+public: // overridden from Writer
+  String write(const Value& root) override;
+
+private:
+  void writeValue(const Value& value);
+
+  String document_;
+  bool yamlCompatibilityEnabled_{false};
+  bool dropNullPlaceholders_{false};
+  bool omitEndingLineFeed_{false};
+};
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
+/** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
+ *human friendly way.
+ *
+ * The rules for line break and indent are as follow:
+ * - Object value:
+ *     - if empty then print {} without indent and line break
+ *     - if not empty the print '{', line break & indent, print one value per
+ *line
+ *       and then unindent and line break and print '}'.
+ * - Array value:
+ *     - if empty then print [] without indent and line break
+ *     - if the array contains no object value, empty array or some other value
+ *types,
+ *       and all the values fit on one lines, then print the array on a single
+ *line.
+ *     - otherwise, it the values do not fit on one line, or the array contains
+ *       object or non empty array, then print one value per line.
+ *
+ * If the Value have comments then they are outputed according to their
+ *#CommentPlacement.
+ *
+ * \sa Reader, Value, Value::setComment()
+ * \deprecated Use StreamWriterBuilder.
+ */
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4996) // Deriving from deprecated class
+#endif
+class JSON_API
+    StyledWriter : public Writer {
+public:
+  StyledWriter();
+  ~StyledWriter() override = default;
+
+public: // overridden from Writer
+  /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
+   * \param root Value to serialize.
+   * \return String containing the JSON document that represents the root value.
+   */
+  String write(const Value& root) override;
+
+private:
+  void writeValue(const Value& value);
+  void writeArrayValue(const Value& value);
+  bool isMultilineArray(const Value& value);
+  void pushValue(const String& value);
+  void writeIndent();
+  void writeWithIndent(const String& value);
+  void indent();
+  void unindent();
+  void writeCommentBeforeValue(const Value& root);
+  void writeCommentAfterValueOnSameLine(const Value& root);
+  static bool hasCommentForValue(const Value& value);
+  static String normalizeEOL(const String& text);
+
+  using ChildValues = std::vector<String>;
+
+  ChildValues childValues_;
+  String document_;
+  String indentString_;
+  unsigned int rightMargin_{74};
+  unsigned int indentSize_{3};
+  bool addChildValues_{false};
+};
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
+/** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a
+ human friendly way,
+     to a stream rather than to a string.
+ *
+ * The rules for line break and indent are as follow:
+ * - Object value:
+ *     - if empty then print {} without indent and line break
+ *     - if not empty the print '{', line break & indent, print one value per
+ line
+ *       and then unindent and line break and print '}'.
+ * - Array value:
+ *     - if empty then print [] without indent and line break
+ *     - if the array contains no object value, empty array or some other value
+ types,
+ *       and all the values fit on one lines, then print the array on a single
+ line.
+ *     - otherwise, it the values do not fit on one line, or the array contains
+ *       object or non empty array, then print one value per line.
+ *
+ * If the Value have comments then they are outputed according to their
+ #CommentPlacement.
+ *
+ * \sa Reader, Value, Value::setComment()
+ * \deprecated Use StreamWriterBuilder.
+ */
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4996) // Deriving from deprecated class
+#endif
+class JSON_API
+    StyledStreamWriter {
+public:
+  /**
+   * \param indentation Each level will be indented by this amount extra.
+   */
+  StyledStreamWriter(String indentation = "\t");
+  ~StyledStreamWriter() = default;
+
+public:
+  /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
+   * \param out Stream to write to. (Can be ostringstream, e.g.)
+   * \param root Value to serialize.
+   * \note There is no point in deriving from Writer, since write() should not
+   * return a value.
+   */
+  void write(OStream& out, const Value& root);
+
+private:
+  void writeValue(const Value& value);
+  void writeArrayValue(const Value& value);
+  bool isMultilineArray(const Value& value);
+  void pushValue(const String& value);
+  void writeIndent();
+  void writeWithIndent(const String& value);
+  void indent();
+  void unindent();
+  void writeCommentBeforeValue(const Value& root);
+  void writeCommentAfterValueOnSameLine(const Value& root);
+  static bool hasCommentForValue(const Value& value);
+  static String normalizeEOL(const String& text);
+
+  using ChildValues = std::vector<String>;
+
+  ChildValues childValues_;
+  OStream* document_;
+  String indentString_;
+  unsigned int rightMargin_{74};
+  String indentation_;
+  bool addChildValues_ : 1;
+  bool indented_ : 1;
+};
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
+#if defined(JSON_HAS_INT64)
+String JSON_API valueToString(Int value);
+String JSON_API valueToString(UInt value);
+#endif // if defined(JSON_HAS_INT64)
+String JSON_API valueToString(LargestInt value);
+String JSON_API valueToString(LargestUInt value);
+String JSON_API valueToString(
+    double value, unsigned int precision = Value::defaultRealPrecision,
+    PrecisionType precisionType = PrecisionType::significantDigits);
+String JSON_API valueToString(bool value);
+String JSON_API valueToQuotedString(const char* value);
+
+/// \brief Output using the StyledStreamWriter.
+/// \see Json::operator>>()
+JSON_API OStream& operator<<(OStream&, const Value& root);
+
+} // namespace Json
+
+#pragma pack(pop)
+
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+#pragma warning(pop)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+#endif // JSON_WRITER_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_reader.cpp b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_reader.cpp
new file mode 100644
index 0000000000..a6a3f4e30d
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_reader.cpp
@@ -0,0 +1,1992 @@
+// Copyright 2007-2011 Baptiste Lepilleur and The JsonCpp Authors
+// Copyright (C) 2016 InfoTeCS JSC. All rights reserved.
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "json_tool.h"
+#include <json/assertions.h>
+#include <json/reader.h>
+#include <json/value.h>
+#endif // if !defined(JSON_IS_AMALGAMATION)
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+#include <iostream>
+#include <istream>
+#include <limits>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <utility>
+
+#include <cstdio>
+#if __cplusplus >= 201103L
+
+#if !defined(sscanf)
+#define sscanf std::sscanf
+#endif
+
+#endif //__cplusplus
+
+#if defined(_MSC_VER)
+#if !defined(_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES)
+#define _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES 1
+#endif //_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES
+#endif //_MSC_VER
+
+#if defined(_MSC_VER)
+// Disable warning about strdup being deprecated.
+#pragma warning(disable : 4996)
+#endif
+
+// Define JSONCPP_DEPRECATED_STACK_LIMIT as an appropriate integer at compile
+// time to change the stack limit
+#if !defined(JSONCPP_DEPRECATED_STACK_LIMIT)
+#define JSONCPP_DEPRECATED_STACK_LIMIT 1000
+#endif
+
+static size_t const stackLimit_g =
+    JSONCPP_DEPRECATED_STACK_LIMIT; // see readValue()
+
+namespace Json {
+
+#if __cplusplus >= 201103L || (defined(_CPPLIB_VER) && _CPPLIB_VER >= 520)
+using CharReaderPtr = std::unique_ptr<CharReader>;
+#else
+using CharReaderPtr = std::auto_ptr<CharReader>;
+#endif
+
+// Implementation of class Features
+// ////////////////////////////////
+
+Features::Features() = default;
+
+Features Features::all() { return {}; }
+
+Features Features::strictMode() {
+  Features features;
+  features.allowComments_ = false;
+  features.strictRoot_ = true;
+  features.allowDroppedNullPlaceholders_ = false;
+  features.allowNumericKeys_ = false;
+  return features;
+}
+
+// Implementation of class Reader
+// ////////////////////////////////
+
+bool Reader::containsNewLine(Reader::Location begin, Reader::Location end) {
+  return std::any_of(begin, end, [](char b) { return b == '\n' || b == '\r'; });
+}
+
+// Class Reader
+// //////////////////////////////////////////////////////////////////
+
+Reader::Reader() : features_(Features::all()) {}
+
+Reader::Reader(const Features& features) : features_(features) {}
+
+bool Reader::parse(const std::string& document, Value& root,
+                   bool collectComments) {
+  document_.assign(document.begin(), document.end());
+  const char* begin = document_.c_str();
+  const char* end = begin + document_.length();
+  return parse(begin, end, root, collectComments);
+}
+
+bool Reader::parse(std::istream& is, Value& root, bool collectComments) {
+  // std::istream_iterator<char> begin(is);
+  // std::istream_iterator<char> end;
+  // Those would allow streamed input from a file, if parse() were a
+  // template function.
+
+  // Since String is reference-counted, this at least does not
+  // create an extra copy.
+  String doc(std::istreambuf_iterator<char>(is), {});
+  return parse(doc.data(), doc.data() + doc.size(), root, collectComments);
+}
+
+bool Reader::parse(const char* beginDoc, const char* endDoc, Value& root,
+                   bool collectComments) {
+  if (!features_.allowComments_) {
+    collectComments = false;
+  }
+
+  begin_ = beginDoc;
+  end_ = endDoc;
+  collectComments_ = collectComments;
+  current_ = begin_;
+  lastValueEnd_ = nullptr;
+  lastValue_ = nullptr;
+  commentsBefore_.clear();
+  errors_.clear();
+  while (!nodes_.empty())
+    nodes_.pop();
+  nodes_.push(&root);
+
+  bool successful = readValue();
+  Token token;
+  skipCommentTokens(token);
+  if (collectComments_ && !commentsBefore_.empty())
+    root.setComment(commentsBefore_, commentAfter);
+  if (features_.strictRoot_) {
+    if (!root.isArray() && !root.isObject()) {
+      // Set error location to start of doc, ideally should be first token found
+      // in doc
+      token.type_ = tokenError;
+      token.start_ = beginDoc;
+      token.end_ = endDoc;
+      addError(
+          "A valid JSON document must be either an array or an object value.",
+          token);
+      return false;
+    }
+  }
+  return successful;
+}
+
+bool Reader::readValue() {
+  // readValue() may call itself only if it calls readObject() or ReadArray().
+  // These methods execute nodes_.push() just before and nodes_.pop)() just
+  // after calling readValue(). parse() executes one nodes_.push(), so > instead
+  // of >=.
+  if (nodes_.size() > stackLimit_g)
+    throwRuntimeError("Exceeded stackLimit in readValue().");
+
+  Token token;
+  skipCommentTokens(token);
+  bool successful = true;
+
+  if (collectComments_ && !commentsBefore_.empty()) {
+    currentValue().setComment(commentsBefore_, commentBefore);
+    commentsBefore_.clear();
+  }
+
+  switch (token.type_) {
+  case tokenObjectBegin:
+    successful = readObject(token);
+    currentValue().setOffsetLimit(current_ - begin_);
+    break;
+  case tokenArrayBegin:
+    successful = readArray(token);
+    currentValue().setOffsetLimit(current_ - begin_);
+    break;
+  case tokenNumber:
+    successful = decodeNumber(token);
+    break;
+  case tokenString:
+    successful = decodeString(token);
+    break;
+  case tokenTrue: {
+    Value v(true);
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenFalse: {
+    Value v(false);
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenNull: {
+    Value v;
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenArraySeparator:
+  case tokenObjectEnd:
+  case tokenArrayEnd:
+    if (features_.allowDroppedNullPlaceholders_) {
+      // "Un-read" the current token and mark the current value as a null
+      // token.
+      current_--;
+      Value v;
+      currentValue().swapPayload(v);
+      currentValue().setOffsetStart(current_ - begin_ - 1);
+      currentValue().setOffsetLimit(current_ - begin_);
+      break;
+    } // Else, fall through...
+  default:
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+    return addError("Syntax error: value, object or array expected.", token);
+  }
+
+  if (collectComments_) {
+    lastValueEnd_ = current_;
+    lastValue_ = &currentValue();
+  }
+
+  return successful;
+}
+
+void Reader::skipCommentTokens(Token& token) {
+  if (features_.allowComments_) {
+    do {
+      readToken(token);
+    } while (token.type_ == tokenComment);
+  } else {
+    readToken(token);
+  }
+}
+
+bool Reader::readToken(Token& token) {
+  skipSpaces();
+  token.start_ = current_;
+  Char c = getNextChar();
+  bool ok = true;
+  switch (c) {
+  case '{':
+    token.type_ = tokenObjectBegin;
+    break;
+  case '}':
+    token.type_ = tokenObjectEnd;
+    break;
+  case '[':
+    token.type_ = tokenArrayBegin;
+    break;
+  case ']':
+    token.type_ = tokenArrayEnd;
+    break;
+  case '"':
+    token.type_ = tokenString;
+    ok = readString();
+    break;
+  case '/':
+    token.type_ = tokenComment;
+    ok = readComment();
+    break;
+  case '0':
+  case '1':
+  case '2':
+  case '3':
+  case '4':
+  case '5':
+  case '6':
+  case '7':
+  case '8':
+  case '9':
+  case '-':
+    token.type_ = tokenNumber;
+    readNumber();
+    break;
+  case 't':
+    token.type_ = tokenTrue;
+    ok = match("rue", 3);
+    break;
+  case 'f':
+    token.type_ = tokenFalse;
+    ok = match("alse", 4);
+    break;
+  case 'n':
+    token.type_ = tokenNull;
+    ok = match("ull", 3);
+    break;
+  case ',':
+    token.type_ = tokenArraySeparator;
+    break;
+  case ':':
+    token.type_ = tokenMemberSeparator;
+    break;
+  case 0:
+    token.type_ = tokenEndOfStream;
+    break;
+  default:
+    ok = false;
+    break;
+  }
+  if (!ok)
+    token.type_ = tokenError;
+  token.end_ = current_;
+  return ok;
+}
+
+void Reader::skipSpaces() {
+  while (current_ != end_) {
+    Char c = *current_;
+    if (c == ' ' || c == '\t' || c == '\r' || c == '\n')
+      ++current_;
+    else
+      break;
+  }
+}
+
+bool Reader::match(const Char* pattern, int patternLength) {
+  if (end_ - current_ < patternLength)
+    return false;
+  int index = patternLength;
+  while (index--)
+    if (current_[index] != pattern[index])
+      return false;
+  current_ += patternLength;
+  return true;
+}
+
+bool Reader::readComment() {
+  Location commentBegin = current_ - 1;
+  Char c = getNextChar();
+  bool successful = false;
+  if (c == '*')
+    successful = readCStyleComment();
+  else if (c == '/')
+    successful = readCppStyleComment();
+  if (!successful)
+    return false;
+
+  if (collectComments_) {
+    CommentPlacement placement = commentBefore;
+    if (lastValueEnd_ && !containsNewLine(lastValueEnd_, commentBegin)) {
+      if (c != '*' || !containsNewLine(commentBegin, current_))
+        placement = commentAfterOnSameLine;
+    }
+
+    addComment(commentBegin, current_, placement);
+  }
+  return true;
+}
+
+String Reader::normalizeEOL(Reader::Location begin, Reader::Location end) {
+  String normalized;
+  normalized.reserve(static_cast<size_t>(end - begin));
+  Reader::Location current = begin;
+  while (current != end) {
+    char c = *current++;
+    if (c == '\r') {
+      if (current != end && *current == '\n')
+        // convert dos EOL
+        ++current;
+      // convert Mac EOL
+      normalized += '\n';
+    } else {
+      normalized += c;
+    }
+  }
+  return normalized;
+}
+
+void Reader::addComment(Location begin, Location end,
+                        CommentPlacement placement) {
+  assert(collectComments_);
+  const String& normalized = normalizeEOL(begin, end);
+  if (placement == commentAfterOnSameLine) {
+    assert(lastValue_ != nullptr);
+    lastValue_->setComment(normalized, placement);
+  } else {
+    commentsBefore_ += normalized;
+  }
+}
+
+bool Reader::readCStyleComment() {
+  while ((current_ + 1) < end_) {
+    Char c = getNextChar();
+    if (c == '*' && *current_ == '/')
+      break;
+  }
+  return getNextChar() == '/';
+}
+
+bool Reader::readCppStyleComment() {
+  while (current_ != end_) {
+    Char c = getNextChar();
+    if (c == '\n')
+      break;
+    if (c == '\r') {
+      // Consume DOS EOL. It will be normalized in addComment.
+      if (current_ != end_ && *current_ == '\n')
+        getNextChar();
+      // Break on Moc OS 9 EOL.
+      break;
+    }
+  }
+  return true;
+}
+
+void Reader::readNumber() {
+  Location p = current_;
+  char c = '0'; // stopgap for already consumed character
+  // integral part
+  while (c >= '0' && c <= '9')
+    c = (current_ = p) < end_ ? *p++ : '\0';
+  // fractional part
+  if (c == '.') {
+    c = (current_ = p) < end_ ? *p++ : '\0';
+    while (c >= '0' && c <= '9')
+      c = (current_ = p) < end_ ? *p++ : '\0';
+  }
+  // exponential part
+  if (c == 'e' || c == 'E') {
+    c = (current_ = p) < end_ ? *p++ : '\0';
+    if (c == '+' || c == '-')
+      c = (current_ = p) < end_ ? *p++ : '\0';
+    while (c >= '0' && c <= '9')
+      c = (current_ = p) < end_ ? *p++ : '\0';
+  }
+}
+
+bool Reader::readString() {
+  Char c = '\0';
+  while (current_ != end_) {
+    c = getNextChar();
+    if (c == '\\')
+      getNextChar();
+    else if (c == '"')
+      break;
+  }
+  return c == '"';
+}
+
+bool Reader::readObject(Token& token) {
+  Token tokenName;
+  String name;
+  Value init(objectValue);
+  currentValue().swapPayload(init);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  while (readToken(tokenName)) {
+    bool initialTokenOk = true;
+    while (tokenName.type_ == tokenComment && initialTokenOk)
+      initialTokenOk = readToken(tokenName);
+    if (!initialTokenOk)
+      break;
+    if (tokenName.type_ == tokenObjectEnd && name.empty()) // empty object
+      return true;
+    name.clear();
+    if (tokenName.type_ == tokenString) {
+      if (!decodeString(tokenName, name))
+        return recoverFromError(tokenObjectEnd);
+    } else if (tokenName.type_ == tokenNumber && features_.allowNumericKeys_) {
+      Value numberName;
+      if (!decodeNumber(tokenName, numberName))
+        return recoverFromError(tokenObjectEnd);
+      name = numberName.asString();
+    } else {
+      break;
+    }
+
+    Token colon;
+    if (!readToken(colon) || colon.type_ != tokenMemberSeparator) {
+      return addErrorAndRecover("Missing ':' after object member name", colon,
+                                tokenObjectEnd);
+    }
+    Value& value = currentValue()[name];
+    nodes_.push(&value);
+    bool ok = readValue();
+    nodes_.pop();
+    if (!ok) // error already set
+      return recoverFromError(tokenObjectEnd);
+
+    Token comma;
+    if (!readToken(comma) ||
+        (comma.type_ != tokenObjectEnd && comma.type_ != tokenArraySeparator &&
+         comma.type_ != tokenComment)) {
+      return addErrorAndRecover("Missing ',' or '}' in object declaration",
+                                comma, tokenObjectEnd);
+    }
+    bool finalizeTokenOk = true;
+    while (comma.type_ == tokenComment && finalizeTokenOk)
+      finalizeTokenOk = readToken(comma);
+    if (comma.type_ == tokenObjectEnd)
+      return true;
+  }
+  return addErrorAndRecover("Missing '}' or object member name", tokenName,
+                            tokenObjectEnd);
+}
+
+bool Reader::readArray(Token& token) {
+  Value init(arrayValue);
+  currentValue().swapPayload(init);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  skipSpaces();
+  if (current_ != end_ && *current_ == ']') // empty array
+  {
+    Token endArray;
+    readToken(endArray);
+    return true;
+  }
+  int index = 0;
+  for (;;) {
+    Value& value = currentValue()[index++];
+    nodes_.push(&value);
+    bool ok = readValue();
+    nodes_.pop();
+    if (!ok) // error already set
+      return recoverFromError(tokenArrayEnd);
+
+    Token currentToken;
+    // Accept Comment after last item in the array.
+    ok = readToken(currentToken);
+    while (currentToken.type_ == tokenComment && ok) {
+      ok = readToken(currentToken);
+    }
+    bool badTokenType = (currentToken.type_ != tokenArraySeparator &&
+                         currentToken.type_ != tokenArrayEnd);
+    if (!ok || badTokenType) {
+      return addErrorAndRecover("Missing ',' or ']' in array declaration",
+                                currentToken, tokenArrayEnd);
+    }
+    if (currentToken.type_ == tokenArrayEnd)
+      break;
+  }
+  return true;
+}
+
+bool Reader::decodeNumber(Token& token) {
+  Value decoded;
+  if (!decodeNumber(token, decoded))
+    return false;
+  currentValue().swapPayload(decoded);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  currentValue().setOffsetLimit(token.end_ - begin_);
+  return true;
+}
+
+bool Reader::decodeNumber(Token& token, Value& decoded) {
+  // Attempts to parse the number as an integer. If the number is
+  // larger than the maximum supported value of an integer then
+  // we decode the number as a double.
+  Location current = token.start_;
+  bool isNegative = *current == '-';
+  if (isNegative)
+    ++current;
+  // TODO: Help the compiler do the div and mod at compile time or get rid of
+  // them.
+  Value::LargestUInt maxIntegerValue =
+      isNegative ? Value::LargestUInt(Value::maxLargestInt) + 1
+                 : Value::maxLargestUInt;
+  Value::LargestUInt threshold = maxIntegerValue / 10;
+  Value::LargestUInt value = 0;
+  while (current < token.end_) {
+    Char c = *current++;
+    if (c < '0' || c > '9')
+      return decodeDouble(token, decoded);
+    auto digit(static_cast<Value::UInt>(c - '0'));
+    if (value >= threshold) {
+      // We've hit or exceeded the max value divided by 10 (rounded down). If
+      // a) we've only just touched the limit, b) this is the last digit, and
+      // c) it's small enough to fit in that rounding delta, we're okay.
+      // Otherwise treat this number as a double to avoid overflow.
+      if (value > threshold || current != token.end_ ||
+          digit > maxIntegerValue % 10) {
+        return decodeDouble(token, decoded);
+      }
+    }
+    value = value * 10 + digit;
+  }
+  if (isNegative && value == maxIntegerValue)
+    decoded = Value::minLargestInt;
+  else if (isNegative)
+    decoded = -Value::LargestInt(value);
+  else if (value <= Value::LargestUInt(Value::maxInt))
+    decoded = Value::LargestInt(value);
+  else
+    decoded = value;
+  return true;
+}
+
+bool Reader::decodeDouble(Token& token) {
+  Value decoded;
+  if (!decodeDouble(token, decoded))
+    return false;
+  currentValue().swapPayload(decoded);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  currentValue().setOffsetLimit(token.end_ - begin_);
+  return true;
+}
+
+bool Reader::decodeDouble(Token& token, Value& decoded) {
+  double value = 0;
+  String buffer(token.start_, token.end_);
+  IStringStream is(buffer);
+  if (!(is >> value))
+    return addError(
+        "'" + String(token.start_, token.end_) + "' is not a number.", token);
+  decoded = value;
+  return true;
+}
+
+bool Reader::decodeString(Token& token) {
+  String decoded_string;
+  if (!decodeString(token, decoded_string))
+    return false;
+  Value decoded(decoded_string);
+  currentValue().swapPayload(decoded);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  currentValue().setOffsetLimit(token.end_ - begin_);
+  return true;
+}
+
+bool Reader::decodeString(Token& token, String& decoded) {
+  decoded.reserve(static_cast<size_t>(token.end_ - token.start_ - 2));
+  Location current = token.start_ + 1; // skip '"'
+  Location end = token.end_ - 1;       // do not include '"'
+  while (current != end) {
+    Char c = *current++;
+    if (c == '"')
+      break;
+    if (c == '\\') {
+      if (current == end)
+        return addError("Empty escape sequence in string", token, current);
+      Char escape = *current++;
+      switch (escape) {
+      case '"':
+        decoded += '"';
+        break;
+      case '/':
+        decoded += '/';
+        break;
+      case '\\':
+        decoded += '\\';
+        break;
+      case 'b':
+        decoded += '\b';
+        break;
+      case 'f':
+        decoded += '\f';
+        break;
+      case 'n':
+        decoded += '\n';
+        break;
+      case 'r':
+        decoded += '\r';
+        break;
+      case 't':
+        decoded += '\t';
+        break;
+      case 'u': {
+        unsigned int unicode;
+        if (!decodeUnicodeCodePoint(token, current, end, unicode))
+          return false;
+        decoded += codePointToUTF8(unicode);
+      } break;
+      default:
+        return addError("Bad escape sequence in string", token, current);
+      }
+    } else {
+      decoded += c;
+    }
+  }
+  return true;
+}
+
+bool Reader::decodeUnicodeCodePoint(Token& token, Location& current,
+                                    Location end, unsigned int& unicode) {
+
+  if (!decodeUnicodeEscapeSequence(token, current, end, unicode))
+    return false;
+  if (unicode >= 0xD800 && unicode <= 0xDBFF) {
+    // surrogate pairs
+    if (end - current < 6)
+      return addError(
+          "additional six characters expected to parse unicode surrogate pair.",
+          token, current);
+    if (*(current++) == '\\' && *(current++) == 'u') {
+      unsigned int surrogatePair;
+      if (decodeUnicodeEscapeSequence(token, current, end, surrogatePair)) {
+        unicode = 0x10000 + ((unicode & 0x3FF) << 10) + (surrogatePair & 0x3FF);
+      } else
+        return false;
+    } else
+      return addError("expecting another \\u token to begin the second half of "
+                      "a unicode surrogate pair",
+                      token, current);
+  }
+  return true;
+}
+
+bool Reader::decodeUnicodeEscapeSequence(Token& token, Location& current,
+                                         Location end,
+                                         unsigned int& ret_unicode) {
+  if (end - current < 4)
+    return addError(
+        "Bad unicode escape sequence in string: four digits expected.", token,
+        current);
+  int unicode = 0;
+  for (int index = 0; index < 4; ++index) {
+    Char c = *current++;
+    unicode *= 16;
+    if (c >= '0' && c <= '9')
+      unicode += c - '0';
+    else if (c >= 'a' && c <= 'f')
+      unicode += c - 'a' + 10;
+    else if (c >= 'A' && c <= 'F')
+      unicode += c - 'A' + 10;
+    else
+      return addError(
+          "Bad unicode escape sequence in string: hexadecimal digit expected.",
+          token, current);
+  }
+  ret_unicode = static_cast<unsigned int>(unicode);
+  return true;
+}
+
+bool Reader::addError(const String& message, Token& token, Location extra) {
+  ErrorInfo info;
+  info.token_ = token;
+  info.message_ = message;
+  info.extra_ = extra;
+  errors_.push_back(info);
+  return false;
+}
+
+bool Reader::recoverFromError(TokenType skipUntilToken) {
+  size_t const errorCount = errors_.size();
+  Token skip;
+  for (;;) {
+    if (!readToken(skip))
+      errors_.resize(errorCount); // discard errors caused by recovery
+    if (skip.type_ == skipUntilToken || skip.type_ == tokenEndOfStream)
+      break;
+  }
+  errors_.resize(errorCount);
+  return false;
+}
+
+bool Reader::addErrorAndRecover(const String& message, Token& token,
+                                TokenType skipUntilToken) {
+  addError(message, token);
+  return recoverFromError(skipUntilToken);
+}
+
+Value& Reader::currentValue() { return *(nodes_.top()); }
+
+Reader::Char Reader::getNextChar() {
+  if (current_ == end_)
+    return 0;
+  return *current_++;
+}
+
+void Reader::getLocationLineAndColumn(Location location, int& line,
+                                      int& column) const {
+  Location current = begin_;
+  Location lastLineStart = current;
+  line = 0;
+  while (current < location && current != end_) {
+    Char c = *current++;
+    if (c == '\r') {
+      if (*current == '\n')
+        ++current;
+      lastLineStart = current;
+      ++line;
+    } else if (c == '\n') {
+      lastLineStart = current;
+      ++line;
+    }
+  }
+  // column & line start at 1
+  column = int(location - lastLineStart) + 1;
+  ++line;
+}
+
+String Reader::getLocationLineAndColumn(Location location) const {
+  int line, column;
+  getLocationLineAndColumn(location, line, column);
+  char buffer[18 + 16 + 16 + 1];
+  jsoncpp_snprintf(buffer, sizeof(buffer), "Line %d, Column %d", line, column);
+  return buffer;
+}
+
+// Deprecated. Preserved for backward compatibility
+String Reader::getFormatedErrorMessages() const {
+  return getFormattedErrorMessages();
+}
+
+String Reader::getFormattedErrorMessages() const {
+  String formattedMessage;
+  for (const auto& error : errors_) {
+    formattedMessage +=
+        "* " + getLocationLineAndColumn(error.token_.start_) + "\n";
+    formattedMessage += "  " + error.message_ + "\n";
+    if (error.extra_)
+      formattedMessage +=
+          "See " + getLocationLineAndColumn(error.extra_) + " for detail.\n";
+  }
+  return formattedMessage;
+}
+
+std::vector<Reader::StructuredError> Reader::getStructuredErrors() const {
+  std::vector<Reader::StructuredError> allErrors;
+  for (const auto& error : errors_) {
+    Reader::StructuredError structured;
+    structured.offset_start = error.token_.start_ - begin_;
+    structured.offset_limit = error.token_.end_ - begin_;
+    structured.message = error.message_;
+    allErrors.push_back(structured);
+  }
+  return allErrors;
+}
+
+bool Reader::pushError(const Value& value, const String& message) {
+  ptrdiff_t const length = end_ - begin_;
+  if (value.getOffsetStart() > length || value.getOffsetLimit() > length)
+    return false;
+  Token token;
+  token.type_ = tokenError;
+  token.start_ = begin_ + value.getOffsetStart();
+  token.end_ = begin_ + value.getOffsetLimit();
+  ErrorInfo info;
+  info.token_ = token;
+  info.message_ = message;
+  info.extra_ = nullptr;
+  errors_.push_back(info);
+  return true;
+}
+
+bool Reader::pushError(const Value& value, const String& message,
+                       const Value& extra) {
+  ptrdiff_t const length = end_ - begin_;
+  if (value.getOffsetStart() > length || value.getOffsetLimit() > length ||
+      extra.getOffsetLimit() > length)
+    return false;
+  Token token;
+  token.type_ = tokenError;
+  token.start_ = begin_ + value.getOffsetStart();
+  token.end_ = begin_ + value.getOffsetLimit();
+  ErrorInfo info;
+  info.token_ = token;
+  info.message_ = message;
+  info.extra_ = begin_ + extra.getOffsetStart();
+  errors_.push_back(info);
+  return true;
+}
+
+bool Reader::good() const { return errors_.empty(); }
+
+// Originally copied from the Features class (now deprecated), used internally
+// for features implementation.
+class OurFeatures {
+public:
+  static OurFeatures all();
+  bool allowComments_;
+  bool allowTrailingCommas_;
+  bool strictRoot_;
+  bool allowDroppedNullPlaceholders_;
+  bool allowNumericKeys_;
+  bool allowSingleQuotes_;
+  bool failIfExtra_;
+  bool rejectDupKeys_;
+  bool allowSpecialFloats_;
+  bool skipBom_;
+  size_t stackLimit_;
+}; // OurFeatures
+
+OurFeatures OurFeatures::all() { return {}; }
+
+// Implementation of class Reader
+// ////////////////////////////////
+
+// Originally copied from the Reader class (now deprecated), used internally
+// for implementing JSON reading.
+class OurReader {
+public:
+  using Char = char;
+  using Location = const Char*;
+  struct StructuredError {
+    ptrdiff_t offset_start;
+    ptrdiff_t offset_limit;
+    String message;
+  };
+
+  explicit OurReader(OurFeatures const& features);
+  bool parse(const char* beginDoc, const char* endDoc, Value& root,
+             bool collectComments = true);
+  String getFormattedErrorMessages() const;
+  std::vector<StructuredError> getStructuredErrors() const;
+
+private:
+  OurReader(OurReader const&);      // no impl
+  void operator=(OurReader const&); // no impl
+
+  enum TokenType {
+    tokenEndOfStream = 0,
+    tokenObjectBegin,
+    tokenObjectEnd,
+    tokenArrayBegin,
+    tokenArrayEnd,
+    tokenString,
+    tokenNumber,
+    tokenTrue,
+    tokenFalse,
+    tokenNull,
+    tokenNaN,
+    tokenPosInf,
+    tokenNegInf,
+    tokenArraySeparator,
+    tokenMemberSeparator,
+    tokenComment,
+    tokenError
+  };
+
+  class Token {
+  public:
+    TokenType type_;
+    Location start_;
+    Location end_;
+  };
+
+  class ErrorInfo {
+  public:
+    Token token_;
+    String message_;
+    Location extra_;
+  };
+
+  using Errors = std::deque<ErrorInfo>;
+
+  bool readToken(Token& token);
+  void skipSpaces();
+  void skipBom(bool skipBom);
+  bool match(const Char* pattern, int patternLength);
+  bool readComment();
+  bool readCStyleComment(bool* containsNewLineResult);
+  bool readCppStyleComment();
+  bool readString();
+  bool readStringSingleQuote();
+  bool readNumber(bool checkInf);
+  bool readValue();
+  bool readObject(Token& token);
+  bool readArray(Token& token);
+  bool decodeNumber(Token& token);
+  bool decodeNumber(Token& token, Value& decoded);
+  bool decodeString(Token& token);
+  bool decodeString(Token& token, String& decoded);
+  bool decodeDouble(Token& token);
+  bool decodeDouble(Token& token, Value& decoded);
+  bool decodeUnicodeCodePoint(Token& token, Location& current, Location end,
+                              unsigned int& unicode);
+  bool decodeUnicodeEscapeSequence(Token& token, Location& current,
+                                   Location end, unsigned int& unicode);
+  bool addError(const String& message, Token& token, Location extra = nullptr);
+  bool recoverFromError(TokenType skipUntilToken);
+  bool addErrorAndRecover(const String& message, Token& token,
+                          TokenType skipUntilToken);
+  void skipUntilSpace();
+  Value& currentValue();
+  Char getNextChar();
+  void getLocationLineAndColumn(Location location, int& line,
+                                int& column) const;
+  String getLocationLineAndColumn(Location location) const;
+  void addComment(Location begin, Location end, CommentPlacement placement);
+  void skipCommentTokens(Token& token);
+
+  static String normalizeEOL(Location begin, Location end);
+  static bool containsNewLine(Location begin, Location end);
+
+  using Nodes = std::stack<Value*>;
+
+  Nodes nodes_{};
+  Errors errors_{};
+  String document_{};
+  Location begin_ = nullptr;
+  Location end_ = nullptr;
+  Location current_ = nullptr;
+  Location lastValueEnd_ = nullptr;
+  Value* lastValue_ = nullptr;
+  bool lastValueHasAComment_ = false;
+  String commentsBefore_{};
+
+  OurFeatures const features_;
+  bool collectComments_ = false;
+}; // OurReader
+
+// complete copy of Read impl, for OurReader
+
+bool OurReader::containsNewLine(OurReader::Location begin,
+                                OurReader::Location end) {
+  return std::any_of(begin, end, [](char b) { return b == '\n' || b == '\r'; });
+}
+
+OurReader::OurReader(OurFeatures const& features) : features_(features) {}
+
+bool OurReader::parse(const char* beginDoc, const char* endDoc, Value& root,
+                      bool collectComments) {
+  if (!features_.allowComments_) {
+    collectComments = false;
+  }
+
+  begin_ = beginDoc;
+  end_ = endDoc;
+  collectComments_ = collectComments;
+  current_ = begin_;
+  lastValueEnd_ = nullptr;
+  lastValue_ = nullptr;
+  commentsBefore_.clear();
+  errors_.clear();
+  while (!nodes_.empty())
+    nodes_.pop();
+  nodes_.push(&root);
+
+  // skip byte order mark if it exists at the beginning of the UTF-8 text.
+  skipBom(features_.skipBom_);
+  bool successful = readValue();
+  nodes_.pop();
+  Token token;
+  skipCommentTokens(token);
+  if (features_.failIfExtra_ && (token.type_ != tokenEndOfStream)) {
+    addError("Extra non-whitespace after JSON value.", token);
+    return false;
+  }
+  if (collectComments_ && !commentsBefore_.empty())
+    root.setComment(commentsBefore_, commentAfter);
+  if (features_.strictRoot_) {
+    if (!root.isArray() && !root.isObject()) {
+      // Set error location to start of doc, ideally should be first token found
+      // in doc
+      token.type_ = tokenError;
+      token.start_ = beginDoc;
+      token.end_ = endDoc;
+      addError(
+          "A valid JSON document must be either an array or an object value.",
+          token);
+      return false;
+    }
+  }
+  return successful;
+}
+
+bool OurReader::readValue() {
+  //  To preserve the old behaviour we cast size_t to int.
+  if (nodes_.size() > features_.stackLimit_)
+    throwRuntimeError("Exceeded stackLimit in readValue().");
+  Token token;
+  skipCommentTokens(token);
+  bool successful = true;
+
+  if (collectComments_ && !commentsBefore_.empty()) {
+    currentValue().setComment(commentsBefore_, commentBefore);
+    commentsBefore_.clear();
+  }
+
+  switch (token.type_) {
+  case tokenObjectBegin:
+    successful = readObject(token);
+    currentValue().setOffsetLimit(current_ - begin_);
+    break;
+  case tokenArrayBegin:
+    successful = readArray(token);
+    currentValue().setOffsetLimit(current_ - begin_);
+    break;
+  case tokenNumber:
+    successful = decodeNumber(token);
+    break;
+  case tokenString:
+    successful = decodeString(token);
+    break;
+  case tokenTrue: {
+    Value v(true);
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenFalse: {
+    Value v(false);
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenNull: {
+    Value v;
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenNaN: {
+    Value v(std::numeric_limits<double>::quiet_NaN());
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenPosInf: {
+    Value v(std::numeric_limits<double>::infinity());
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenNegInf: {
+    Value v(-std::numeric_limits<double>::infinity());
+    currentValue().swapPayload(v);
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+  } break;
+  case tokenArraySeparator:
+  case tokenObjectEnd:
+  case tokenArrayEnd:
+    if (features_.allowDroppedNullPlaceholders_) {
+      // "Un-read" the current token and mark the current value as a null
+      // token.
+      current_--;
+      Value v;
+      currentValue().swapPayload(v);
+      currentValue().setOffsetStart(current_ - begin_ - 1);
+      currentValue().setOffsetLimit(current_ - begin_);
+      break;
+    } // else, fall through ...
+  default:
+    currentValue().setOffsetStart(token.start_ - begin_);
+    currentValue().setOffsetLimit(token.end_ - begin_);
+    return addError("Syntax error: value, object or array expected.", token);
+  }
+
+  if (collectComments_) {
+    lastValueEnd_ = current_;
+    lastValueHasAComment_ = false;
+    lastValue_ = &currentValue();
+  }
+
+  return successful;
+}
+
+void OurReader::skipCommentTokens(Token& token) {
+  if (features_.allowComments_) {
+    do {
+      readToken(token);
+    } while (token.type_ == tokenComment);
+  } else {
+    readToken(token);
+  }
+}
+
+bool OurReader::readToken(Token& token) {
+  skipSpaces();
+  token.start_ = current_;
+  Char c = getNextChar();
+  bool ok = true;
+  switch (c) {
+  case '{':
+    token.type_ = tokenObjectBegin;
+    break;
+  case '}':
+    token.type_ = tokenObjectEnd;
+    break;
+  case '[':
+    token.type_ = tokenArrayBegin;
+    break;
+  case ']':
+    token.type_ = tokenArrayEnd;
+    break;
+  case '"':
+    token.type_ = tokenString;
+    ok = readString();
+    break;
+  case '\'':
+    if (features_.allowSingleQuotes_) {
+      token.type_ = tokenString;
+      ok = readStringSingleQuote();
+    } else {
+      // If we don't allow single quotes, this is a failure case.
+      ok = false;
+    }
+    break;
+  case '/':
+    token.type_ = tokenComment;
+    ok = readComment();
+    break;
+  case '0':
+  case '1':
+  case '2':
+  case '3':
+  case '4':
+  case '5':
+  case '6':
+  case '7':
+  case '8':
+  case '9':
+    token.type_ = tokenNumber;
+    readNumber(false);
+    break;
+  case '-':
+    if (readNumber(true)) {
+      token.type_ = tokenNumber;
+    } else {
+      token.type_ = tokenNegInf;
+      ok = features_.allowSpecialFloats_ && match("nfinity", 7);
+    }
+    break;
+  case '+':
+    if (readNumber(true)) {
+      token.type_ = tokenNumber;
+    } else {
+      token.type_ = tokenPosInf;
+      ok = features_.allowSpecialFloats_ && match("nfinity", 7);
+    }
+    break;
+  case 't':
+    token.type_ = tokenTrue;
+    ok = match("rue", 3);
+    break;
+  case 'f':
+    token.type_ = tokenFalse;
+    ok = match("alse", 4);
+    break;
+  case 'n':
+    token.type_ = tokenNull;
+    ok = match("ull", 3);
+    break;
+  case 'N':
+    if (features_.allowSpecialFloats_) {
+      token.type_ = tokenNaN;
+      ok = match("aN", 2);
+    } else {
+      ok = false;
+    }
+    break;
+  case 'I':
+    if (features_.allowSpecialFloats_) {
+      token.type_ = tokenPosInf;
+      ok = match("nfinity", 7);
+    } else {
+      ok = false;
+    }
+    break;
+  case ',':
+    token.type_ = tokenArraySeparator;
+    break;
+  case ':':
+    token.type_ = tokenMemberSeparator;
+    break;
+  case 0:
+    token.type_ = tokenEndOfStream;
+    break;
+  default:
+    ok = false;
+    break;
+  }
+  if (!ok)
+    token.type_ = tokenError;
+  token.end_ = current_;
+  return ok;
+}
+
+void OurReader::skipSpaces() {
+  while (current_ != end_) {
+    Char c = *current_;
+    if (c == ' ' || c == '\t' || c == '\r' || c == '\n')
+      ++current_;
+    else
+      break;
+  }
+}
+
+void OurReader::skipBom(bool skipBom) {
+  // The default behavior is to skip BOM.
+  if (skipBom) {
+    if ((end_ - begin_) >= 3 && strncmp(begin_, "\xEF\xBB\xBF", 3) == 0) {
+      begin_ += 3;
+      current_ = begin_;
+    }
+  }
+}
+
+bool OurReader::match(const Char* pattern, int patternLength) {
+  if (end_ - current_ < patternLength)
+    return false;
+  int index = patternLength;
+  while (index--)
+    if (current_[index] != pattern[index])
+      return false;
+  current_ += patternLength;
+  return true;
+}
+
+bool OurReader::readComment() {
+  const Location commentBegin = current_ - 1;
+  const Char c = getNextChar();
+  bool successful = false;
+  bool cStyleWithEmbeddedNewline = false;
+
+  const bool isCStyleComment = (c == '*');
+  const bool isCppStyleComment = (c == '/');
+  if (isCStyleComment) {
+    successful = readCStyleComment(&cStyleWithEmbeddedNewline);
+  } else if (isCppStyleComment) {
+    successful = readCppStyleComment();
+  }
+
+  if (!successful)
+    return false;
+
+  if (collectComments_) {
+    CommentPlacement placement = commentBefore;
+
+    if (!lastValueHasAComment_) {
+      if (lastValueEnd_ && !containsNewLine(lastValueEnd_, commentBegin)) {
+        if (isCppStyleComment || !cStyleWithEmbeddedNewline) {
+          placement = commentAfterOnSameLine;
+          lastValueHasAComment_ = true;
+        }
+      }
+    }
+
+    addComment(commentBegin, current_, placement);
+  }
+  return true;
+}
+
+String OurReader::normalizeEOL(OurReader::Location begin,
+                               OurReader::Location end) {
+  String normalized;
+  normalized.reserve(static_cast<size_t>(end - begin));
+  OurReader::Location current = begin;
+  while (current != end) {
+    char c = *current++;
+    if (c == '\r') {
+      if (current != end && *current == '\n')
+        // convert dos EOL
+        ++current;
+      // convert Mac EOL
+      normalized += '\n';
+    } else {
+      normalized += c;
+    }
+  }
+  return normalized;
+}
+
+void OurReader::addComment(Location begin, Location end,
+                           CommentPlacement placement) {
+  assert(collectComments_);
+  const String& normalized = normalizeEOL(begin, end);
+  if (placement == commentAfterOnSameLine) {
+    assert(lastValue_ != nullptr);
+    lastValue_->setComment(normalized, placement);
+  } else {
+    commentsBefore_ += normalized;
+  }
+}
+
+bool OurReader::readCStyleComment(bool* containsNewLineResult) {
+  *containsNewLineResult = false;
+
+  while ((current_ + 1) < end_) {
+    Char c = getNextChar();
+    if (c == '*' && *current_ == '/')
+      break;
+    if (c == '\n')
+      *containsNewLineResult = true;
+  }
+
+  return getNextChar() == '/';
+}
+
+bool OurReader::readCppStyleComment() {
+  while (current_ != end_) {
+    Char c = getNextChar();
+    if (c == '\n')
+      break;
+    if (c == '\r') {
+      // Consume DOS EOL. It will be normalized in addComment.
+      if (current_ != end_ && *current_ == '\n')
+        getNextChar();
+      // Break on Moc OS 9 EOL.
+      break;
+    }
+  }
+  return true;
+}
+
+bool OurReader::readNumber(bool checkInf) {
+  Location p = current_;
+  if (checkInf && p != end_ && *p == 'I') {
+    current_ = ++p;
+    return false;
+  }
+  char c = '0'; // stopgap for already consumed character
+  // integral part
+  while (c >= '0' && c <= '9')
+    c = (current_ = p) < end_ ? *p++ : '\0';
+  // fractional part
+  if (c == '.') {
+    c = (current_ = p) < end_ ? *p++ : '\0';
+    while (c >= '0' && c <= '9')
+      c = (current_ = p) < end_ ? *p++ : '\0';
+  }
+  // exponential part
+  if (c == 'e' || c == 'E') {
+    c = (current_ = p) < end_ ? *p++ : '\0';
+    if (c == '+' || c == '-')
+      c = (current_ = p) < end_ ? *p++ : '\0';
+    while (c >= '0' && c <= '9')
+      c = (current_ = p) < end_ ? *p++ : '\0';
+  }
+  return true;
+}
+bool OurReader::readString() {
+  Char c = 0;
+  while (current_ != end_) {
+    c = getNextChar();
+    if (c == '\\')
+      getNextChar();
+    else if (c == '"')
+      break;
+  }
+  return c == '"';
+}
+
+bool OurReader::readStringSingleQuote() {
+  Char c = 0;
+  while (current_ != end_) {
+    c = getNextChar();
+    if (c == '\\')
+      getNextChar();
+    else if (c == '\'')
+      break;
+  }
+  return c == '\'';
+}
+
+bool OurReader::readObject(Token& token) {
+  Token tokenName;
+  String name;
+  Value init(objectValue);
+  currentValue().swapPayload(init);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  while (readToken(tokenName)) {
+    bool initialTokenOk = true;
+    while (tokenName.type_ == tokenComment && initialTokenOk)
+      initialTokenOk = readToken(tokenName);
+    if (!initialTokenOk)
+      break;
+    if (tokenName.type_ == tokenObjectEnd &&
+        (name.empty() ||
+         features_.allowTrailingCommas_)) // empty object or trailing comma
+      return true;
+    name.clear();
+    if (tokenName.type_ == tokenString) {
+      if (!decodeString(tokenName, name))
+        return recoverFromError(tokenObjectEnd);
+    } else if (tokenName.type_ == tokenNumber && features_.allowNumericKeys_) {
+      Value numberName;
+      if (!decodeNumber(tokenName, numberName))
+        return recoverFromError(tokenObjectEnd);
+      name = numberName.asString();
+    } else {
+      break;
+    }
+    if (name.length() >= (1U << 30))
+      throwRuntimeError("keylength >= 2^30");
+    if (features_.rejectDupKeys_ && currentValue().isMember(name)) {
+      String msg = "Duplicate key: '" + name + "'";
+      return addErrorAndRecover(msg, tokenName, tokenObjectEnd);
+    }
+
+    Token colon;
+    if (!readToken(colon) || colon.type_ != tokenMemberSeparator) {
+      return addErrorAndRecover("Missing ':' after object member name", colon,
+                                tokenObjectEnd);
+    }
+    Value& value = currentValue()[name];
+    nodes_.push(&value);
+    bool ok = readValue();
+    nodes_.pop();
+    if (!ok) // error already set
+      return recoverFromError(tokenObjectEnd);
+
+    Token comma;
+    if (!readToken(comma) ||
+        (comma.type_ != tokenObjectEnd && comma.type_ != tokenArraySeparator &&
+         comma.type_ != tokenComment)) {
+      return addErrorAndRecover("Missing ',' or '}' in object declaration",
+                                comma, tokenObjectEnd);
+    }
+    bool finalizeTokenOk = true;
+    while (comma.type_ == tokenComment && finalizeTokenOk)
+      finalizeTokenOk = readToken(comma);
+    if (comma.type_ == tokenObjectEnd)
+      return true;
+  }
+  return addErrorAndRecover("Missing '}' or object member name", tokenName,
+                            tokenObjectEnd);
+}
+
+bool OurReader::readArray(Token& token) {
+  Value init(arrayValue);
+  currentValue().swapPayload(init);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  int index = 0;
+  for (;;) {
+    skipSpaces();
+    if (current_ != end_ && *current_ == ']' &&
+        (index == 0 ||
+         (features_.allowTrailingCommas_ &&
+          !features_.allowDroppedNullPlaceholders_))) // empty array or trailing
+                                                      // comma
+    {
+      Token endArray;
+      readToken(endArray);
+      return true;
+    }
+    Value& value = currentValue()[index++];
+    nodes_.push(&value);
+    bool ok = readValue();
+    nodes_.pop();
+    if (!ok) // error already set
+      return recoverFromError(tokenArrayEnd);
+
+    Token currentToken;
+    // Accept Comment after last item in the array.
+    ok = readToken(currentToken);
+    while (currentToken.type_ == tokenComment && ok) {
+      ok = readToken(currentToken);
+    }
+    bool badTokenType = (currentToken.type_ != tokenArraySeparator &&
+                         currentToken.type_ != tokenArrayEnd);
+    if (!ok || badTokenType) {
+      return addErrorAndRecover("Missing ',' or ']' in array declaration",
+                                currentToken, tokenArrayEnd);
+    }
+    if (currentToken.type_ == tokenArrayEnd)
+      break;
+  }
+  return true;
+}
+
+bool OurReader::decodeNumber(Token& token) {
+  Value decoded;
+  if (!decodeNumber(token, decoded))
+    return false;
+  currentValue().swapPayload(decoded);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  currentValue().setOffsetLimit(token.end_ - begin_);
+  return true;
+}
+
+bool OurReader::decodeNumber(Token& token, Value& decoded) {
+  // Attempts to parse the number as an integer. If the number is
+  // larger than the maximum supported value of an integer then
+  // we decode the number as a double.
+  Location current = token.start_;
+  const bool isNegative = *current == '-';
+  if (isNegative) {
+    ++current;
+  }
+
+  // We assume we can represent the largest and smallest integer types as
+  // unsigned integers with separate sign. This is only true if they can fit
+  // into an unsigned integer.
+  static_assert(Value::maxLargestInt <= Value::maxLargestUInt,
+                "Int must be smaller than UInt");
+
+  // We need to convert minLargestInt into a positive number. The easiest way
+  // to do this conversion is to assume our "threshold" value of minLargestInt
+  // divided by 10 can fit in maxLargestInt when absolute valued. This should
+  // be a safe assumption.
+  static_assert(Value::minLargestInt <= -Value::maxLargestInt,
+                "The absolute value of minLargestInt must be greater than or "
+                "equal to maxLargestInt");
+  static_assert(Value::minLargestInt / 10 >= -Value::maxLargestInt,
+                "The absolute value of minLargestInt must be only 1 magnitude "
+                "larger than maxLargest Int");
+
+  static constexpr Value::LargestUInt positive_threshold =
+      Value::maxLargestUInt / 10;
+  static constexpr Value::UInt positive_last_digit = Value::maxLargestUInt % 10;
+
+  // For the negative values, we have to be more careful. Since typically
+  // -Value::minLargestInt will cause an overflow, we first divide by 10 and
+  // then take the inverse. This assumes that minLargestInt is only a single
+  // power of 10 different in magnitude, which we check above. For the last
+  // digit, we take the modulus before negating for the same reason.
+  static constexpr auto negative_threshold =
+      Value::LargestUInt(-(Value::minLargestInt / 10));
+  static constexpr auto negative_last_digit =
+      Value::UInt(-(Value::minLargestInt % 10));
+
+  const Value::LargestUInt threshold =
+      isNegative ? negative_threshold : positive_threshold;
+  const Value::UInt max_last_digit =
+      isNegative ? negative_last_digit : positive_last_digit;
+
+  Value::LargestUInt value = 0;
+  while (current < token.end_) {
+    Char c = *current++;
+    if (c < '0' || c > '9')
+      return decodeDouble(token, decoded);
+
+    const auto digit(static_cast<Value::UInt>(c - '0'));
+    if (value >= threshold) {
+      // We've hit or exceeded the max value divided by 10 (rounded down). If
+      // a) we've only just touched the limit, meaing value == threshold,
+      // b) this is the last digit, or
+      // c) it's small enough to fit in that rounding delta, we're okay.
+      // Otherwise treat this number as a double to avoid overflow.
+      if (value > threshold || current != token.end_ ||
+          digit > max_last_digit) {
+        return decodeDouble(token, decoded);
+      }
+    }
+    value = value * 10 + digit;
+  }
+
+  if (isNegative) {
+    // We use the same magnitude assumption here, just in case.
+    const auto last_digit = static_cast<Value::UInt>(value % 10);
+    decoded = -Value::LargestInt(value / 10) * 10 - last_digit;
+  } else if (value <= Value::LargestUInt(Value::maxLargestInt)) {
+    decoded = Value::LargestInt(value);
+  } else {
+    decoded = value;
+  }
+
+  return true;
+}
+
+bool OurReader::decodeDouble(Token& token) {
+  Value decoded;
+  if (!decodeDouble(token, decoded))
+    return false;
+  currentValue().swapPayload(decoded);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  currentValue().setOffsetLimit(token.end_ - begin_);
+  return true;
+}
+
+bool OurReader::decodeDouble(Token& token, Value& decoded) {
+  double value = 0;
+  const String buffer(token.start_, token.end_);
+  IStringStream is(buffer);
+  if (!(is >> value)) {
+    return addError(
+        "'" + String(token.start_, token.end_) + "' is not a number.", token);
+  }
+  decoded = value;
+  return true;
+}
+
+bool OurReader::decodeString(Token& token) {
+  String decoded_string;
+  if (!decodeString(token, decoded_string))
+    return false;
+  Value decoded(decoded_string);
+  currentValue().swapPayload(decoded);
+  currentValue().setOffsetStart(token.start_ - begin_);
+  currentValue().setOffsetLimit(token.end_ - begin_);
+  return true;
+}
+
+bool OurReader::decodeString(Token& token, String& decoded) {
+  decoded.reserve(static_cast<size_t>(token.end_ - token.start_ - 2));
+  Location current = token.start_ + 1; // skip '"'
+  Location end = token.end_ - 1;       // do not include '"'
+  while (current != end) {
+    Char c = *current++;
+    if (c == '"')
+      break;
+    if (c == '\\') {
+      if (current == end)
+        return addError("Empty escape sequence in string", token, current);
+      Char escape = *current++;
+      switch (escape) {
+      case '"':
+        decoded += '"';
+        break;
+      case '/':
+        decoded += '/';
+        break;
+      case '\\':
+        decoded += '\\';
+        break;
+      case 'b':
+        decoded += '\b';
+        break;
+      case 'f':
+        decoded += '\f';
+        break;
+      case 'n':
+        decoded += '\n';
+        break;
+      case 'r':
+        decoded += '\r';
+        break;
+      case 't':
+        decoded += '\t';
+        break;
+      case 'u': {
+        unsigned int unicode;
+        if (!decodeUnicodeCodePoint(token, current, end, unicode))
+          return false;
+        decoded += codePointToUTF8(unicode);
+      } break;
+      default:
+        return addError("Bad escape sequence in string", token, current);
+      }
+    } else {
+      decoded += c;
+    }
+  }
+  return true;
+}
+
+bool OurReader::decodeUnicodeCodePoint(Token& token, Location& current,
+                                       Location end, unsigned int& unicode) {
+
+  if (!decodeUnicodeEscapeSequence(token, current, end, unicode))
+    return false;
+  if (unicode >= 0xD800 && unicode <= 0xDBFF) {
+    // surrogate pairs
+    if (end - current < 6)
+      return addError(
+          "additional six characters expected to parse unicode surrogate pair.",
+          token, current);
+    if (*(current++) == '\\' && *(current++) == 'u') {
+      unsigned int surrogatePair;
+      if (decodeUnicodeEscapeSequence(token, current, end, surrogatePair)) {
+        unicode = 0x10000 + ((unicode & 0x3FF) << 10) + (surrogatePair & 0x3FF);
+      } else
+        return false;
+    } else
+      return addError("expecting another \\u token to begin the second half of "
+                      "a unicode surrogate pair",
+                      token, current);
+  }
+  return true;
+}
+
+bool OurReader::decodeUnicodeEscapeSequence(Token& token, Location& current,
+                                            Location end,
+                                            unsigned int& ret_unicode) {
+  if (end - current < 4)
+    return addError(
+        "Bad unicode escape sequence in string: four digits expected.", token,
+        current);
+  int unicode = 0;
+  for (int index = 0; index < 4; ++index) {
+    Char c = *current++;
+    unicode *= 16;
+    if (c >= '0' && c <= '9')
+      unicode += c - '0';
+    else if (c >= 'a' && c <= 'f')
+      unicode += c - 'a' + 10;
+    else if (c >= 'A' && c <= 'F')
+      unicode += c - 'A' + 10;
+    else
+      return addError(
+          "Bad unicode escape sequence in string: hexadecimal digit expected.",
+          token, current);
+  }
+  ret_unicode = static_cast<unsigned int>(unicode);
+  return true;
+}
+
+bool OurReader::addError(const String& message, Token& token, Location extra) {
+  ErrorInfo info;
+  info.token_ = token;
+  info.message_ = message;
+  info.extra_ = extra;
+  errors_.push_back(info);
+  return false;
+}
+
+bool OurReader::recoverFromError(TokenType skipUntilToken) {
+  size_t errorCount = errors_.size();
+  Token skip;
+  for (;;) {
+    if (!readToken(skip))
+      errors_.resize(errorCount); // discard errors caused by recovery
+    if (skip.type_ == skipUntilToken || skip.type_ == tokenEndOfStream)
+      break;
+  }
+  errors_.resize(errorCount);
+  return false;
+}
+
+bool OurReader::addErrorAndRecover(const String& message, Token& token,
+                                   TokenType skipUntilToken) {
+  addError(message, token);
+  return recoverFromError(skipUntilToken);
+}
+
+Value& OurReader::currentValue() { return *(nodes_.top()); }
+
+OurReader::Char OurReader::getNextChar() {
+  if (current_ == end_)
+    return 0;
+  return *current_++;
+}
+
+void OurReader::getLocationLineAndColumn(Location location, int& line,
+                                         int& column) const {
+  Location current = begin_;
+  Location lastLineStart = current;
+  line = 0;
+  while (current < location && current != end_) {
+    Char c = *current++;
+    if (c == '\r') {
+      if (*current == '\n')
+        ++current;
+      lastLineStart = current;
+      ++line;
+    } else if (c == '\n') {
+      lastLineStart = current;
+      ++line;
+    }
+  }
+  // column & line start at 1
+  column = int(location - lastLineStart) + 1;
+  ++line;
+}
+
+String OurReader::getLocationLineAndColumn(Location location) const {
+  int line, column;
+  getLocationLineAndColumn(location, line, column);
+  char buffer[18 + 16 + 16 + 1];
+  jsoncpp_snprintf(buffer, sizeof(buffer), "Line %d, Column %d", line, column);
+  return buffer;
+}
+
+String OurReader::getFormattedErrorMessages() const {
+  String formattedMessage;
+  for (const auto& error : errors_) {
+    formattedMessage +=
+        "* " + getLocationLineAndColumn(error.token_.start_) + "\n";
+    formattedMessage += "  " + error.message_ + "\n";
+    if (error.extra_)
+      formattedMessage +=
+          "See " + getLocationLineAndColumn(error.extra_) + " for detail.\n";
+  }
+  return formattedMessage;
+}
+
+std::vector<OurReader::StructuredError> OurReader::getStructuredErrors() const {
+  std::vector<OurReader::StructuredError> allErrors;
+  for (const auto& error : errors_) {
+    OurReader::StructuredError structured;
+    structured.offset_start = error.token_.start_ - begin_;
+    structured.offset_limit = error.token_.end_ - begin_;
+    structured.message = error.message_;
+    allErrors.push_back(structured);
+  }
+  return allErrors;
+}
+
+class OurCharReader : public CharReader {
+  bool const collectComments_;
+  OurReader reader_;
+
+public:
+  OurCharReader(bool collectComments, OurFeatures const& features)
+      : collectComments_(collectComments), reader_(features) {}
+  bool parse(char const* beginDoc, char const* endDoc, Value* root,
+             String* errs) override {
+    bool ok = reader_.parse(beginDoc, endDoc, *root, collectComments_);
+    if (errs) {
+      *errs = reader_.getFormattedErrorMessages();
+    }
+    return ok;
+  }
+};
+
+CharReaderBuilder::CharReaderBuilder() { setDefaults(&settings_); }
+CharReaderBuilder::~CharReaderBuilder() = default;
+CharReader* CharReaderBuilder::newCharReader() const {
+  bool collectComments = settings_["collectComments"].asBool();
+  OurFeatures features = OurFeatures::all();
+  features.allowComments_ = settings_["allowComments"].asBool();
+  features.allowTrailingCommas_ = settings_["allowTrailingCommas"].asBool();
+  features.strictRoot_ = settings_["strictRoot"].asBool();
+  features.allowDroppedNullPlaceholders_ =
+      settings_["allowDroppedNullPlaceholders"].asBool();
+  features.allowNumericKeys_ = settings_["allowNumericKeys"].asBool();
+  features.allowSingleQuotes_ = settings_["allowSingleQuotes"].asBool();
+
+  // Stack limit is always a size_t, so we get this as an unsigned int
+  // regardless of it we have 64-bit integer support enabled.
+  features.stackLimit_ = static_cast<size_t>(settings_["stackLimit"].asUInt());
+  features.failIfExtra_ = settings_["failIfExtra"].asBool();
+  features.rejectDupKeys_ = settings_["rejectDupKeys"].asBool();
+  features.allowSpecialFloats_ = settings_["allowSpecialFloats"].asBool();
+  features.skipBom_ = settings_["skipBom"].asBool();
+  return new OurCharReader(collectComments, features);
+}
+
+bool CharReaderBuilder::validate(Json::Value* invalid) const {
+  static const auto& valid_keys = *new std::set<String>{
+      "collectComments",
+      "allowComments",
+      "allowTrailingCommas",
+      "strictRoot",
+      "allowDroppedNullPlaceholders",
+      "allowNumericKeys",
+      "allowSingleQuotes",
+      "stackLimit",
+      "failIfExtra",
+      "rejectDupKeys",
+      "allowSpecialFloats",
+      "skipBom",
+  };
+  for (auto si = settings_.begin(); si != settings_.end(); ++si) {
+    auto key = si.name();
+    if (valid_keys.count(key))
+      continue;
+    if (invalid)
+      (*invalid)[key] = *si;
+    else
+      return false;
+  }
+  return invalid ? invalid->empty() : true;
+}
+
+Value& CharReaderBuilder::operator[](const String& key) {
+  return settings_[key];
+}
+// static
+void CharReaderBuilder::strictMode(Json::Value* settings) {
+  //! [CharReaderBuilderStrictMode]
+  (*settings)["allowComments"] = false;
+  (*settings)["allowTrailingCommas"] = false;
+  (*settings)["strictRoot"] = true;
+  (*settings)["allowDroppedNullPlaceholders"] = false;
+  (*settings)["allowNumericKeys"] = false;
+  (*settings)["allowSingleQuotes"] = false;
+  (*settings)["stackLimit"] = 1000;
+  (*settings)["failIfExtra"] = true;
+  (*settings)["rejectDupKeys"] = true;
+  (*settings)["allowSpecialFloats"] = false;
+  (*settings)["skipBom"] = true;
+  //! [CharReaderBuilderStrictMode]
+}
+// static
+void CharReaderBuilder::setDefaults(Json::Value* settings) {
+  //! [CharReaderBuilderDefaults]
+  (*settings)["collectComments"] = true;
+  (*settings)["allowComments"] = true;
+  (*settings)["allowTrailingCommas"] = true;
+  (*settings)["strictRoot"] = false;
+  (*settings)["allowDroppedNullPlaceholders"] = false;
+  (*settings)["allowNumericKeys"] = false;
+  (*settings)["allowSingleQuotes"] = false;
+  (*settings)["stackLimit"] = 1000;
+  (*settings)["failIfExtra"] = false;
+  (*settings)["rejectDupKeys"] = false;
+  (*settings)["allowSpecialFloats"] = false;
+  (*settings)["skipBom"] = true;
+  //! [CharReaderBuilderDefaults]
+}
+
+//////////////////////////////////
+// global functions
+
+bool parseFromStream(CharReader::Factory const& fact, IStream& sin, Value* root,
+                     String* errs) {
+  OStringStream ssin;
+  ssin << sin.rdbuf();
+  String doc = ssin.str();
+  char const* begin = doc.data();
+  char const* end = begin + doc.size();
+  // Note that we do not actually need a null-terminator.
+  CharReaderPtr const reader(fact.newCharReader());
+  return reader->parse(begin, end, root, errs);
+}
+
+IStream& operator>>(IStream& sin, Value& root) {
+  CharReaderBuilder b;
+  String errs;
+  bool ok = parseFromStream(b, sin, &root, &errs);
+  if (!ok) {
+    throwRuntimeError(errs);
+  }
+  return sin;
+}
+
+} // namespace Json
diff --git a/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_tool.h b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_tool.h
new file mode 100644
index 0000000000..b952c19167
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_tool.h
@@ -0,0 +1,138 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#ifndef LIB_JSONCPP_JSON_TOOL_H_INCLUDED
+#define LIB_JSONCPP_JSON_TOOL_H_INCLUDED
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include <json/config.h>
+#endif
+
+// Also support old flag NO_LOCALE_SUPPORT
+#ifdef NO_LOCALE_SUPPORT
+#define JSONCPP_NO_LOCALE_SUPPORT
+#endif
+
+#ifndef JSONCPP_NO_LOCALE_SUPPORT
+#include <clocale>
+#endif
+
+/* This header provides common string manipulation support, such as UTF-8,
+ * portable conversion from/to string...
+ *
+ * It is an internal header that must not be exposed.
+ */
+
+namespace Json {
+static inline char getDecimalPoint() {
+#ifdef JSONCPP_NO_LOCALE_SUPPORT
+  return '\0';
+#else
+  struct lconv* lc = localeconv();
+  return lc ? *(lc->decimal_point) : '\0';
+#endif
+}
+
+/// Converts a unicode code-point to UTF-8.
+static inline String codePointToUTF8(unsigned int cp) {
+  String result;
+
+  // based on description from http://en.wikipedia.org/wiki/UTF-8
+
+  if (cp <= 0x7f) {
+    result.resize(1);
+    result[0] = static_cast<char>(cp);
+  } else if (cp <= 0x7FF) {
+    result.resize(2);
+    result[1] = static_cast<char>(0x80 | (0x3f & cp));
+    result[0] = static_cast<char>(0xC0 | (0x1f & (cp >> 6)));
+  } else if (cp <= 0xFFFF) {
+    result.resize(3);
+    result[2] = static_cast<char>(0x80 | (0x3f & cp));
+    result[1] = static_cast<char>(0x80 | (0x3f & (cp >> 6)));
+    result[0] = static_cast<char>(0xE0 | (0xf & (cp >> 12)));
+  } else if (cp <= 0x10FFFF) {
+    result.resize(4);
+    result[3] = static_cast<char>(0x80 | (0x3f & cp));
+    result[2] = static_cast<char>(0x80 | (0x3f & (cp >> 6)));
+    result[1] = static_cast<char>(0x80 | (0x3f & (cp >> 12)));
+    result[0] = static_cast<char>(0xF0 | (0x7 & (cp >> 18)));
+  }
+
+  return result;
+}
+
+enum {
+  /// Constant that specify the size of the buffer that must be passed to
+  /// uintToString.
+  uintToStringBufferSize = 3 * sizeof(LargestUInt) + 1
+};
+
+// Defines a char buffer for use with uintToString().
+using UIntToStringBuffer = char[uintToStringBufferSize];
+
+/** Converts an unsigned integer to string.
+ * @param value Unsigned integer to convert to string
+ * @param current Input/Output string buffer.
+ *        Must have at least uintToStringBufferSize chars free.
+ */
+static inline void uintToString(LargestUInt value, char*& current) {
+  *--current = 0;
+  do {
+    *--current = static_cast<char>(value % 10U + static_cast<unsigned>('0'));
+    value /= 10;
+  } while (value != 0);
+}
+
+/** Change ',' to '.' everywhere in buffer.
+ *
+ * We had a sophisticated way, but it did not work in WinCE.
+ * @see https://github.com/open-source-parsers/jsoncpp/pull/9
+ */
+template <typename Iter> Iter fixNumericLocale(Iter begin, Iter end) {
+  for (; begin != end; ++begin) {
+    if (*begin == ',') {
+      *begin = '.';
+    }
+  }
+  return begin;
+}
+
+template <typename Iter> void fixNumericLocaleInput(Iter begin, Iter end) {
+  char decimalPoint = getDecimalPoint();
+  if (decimalPoint == '\0' || decimalPoint == '.') {
+    return;
+  }
+  for (; begin != end; ++begin) {
+    if (*begin == '.') {
+      *begin = decimalPoint;
+    }
+  }
+}
+
+/**
+ * Return iterator that would be the new end of the range [begin,end), if we
+ * were to delete zeros in the end of string, but not the last zero before '.'.
+ */
+template <typename Iter>
+Iter fixZerosInTheEnd(Iter begin, Iter end, unsigned int precision) {
+  for (; begin != end; --end) {
+    if (*(end - 1) != '0') {
+      return end;
+    }
+    // Don't delete the last zero before the decimal point.
+    if (begin != (end - 1) && begin != (end - 2) && *(end - 2) == '.') {
+      if (precision) {
+        return end;
+      }
+      return end - 2;
+    }
+  }
+  return end;
+}
+
+} // namespace Json
+
+#endif // LIB_JSONCPP_JSON_TOOL_H_INCLUDED
diff --git a/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_value.cpp b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_value.cpp
new file mode 100644
index 0000000000..aa2b744ca8
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_value.cpp
@@ -0,0 +1,1634 @@
+// Copyright 2011 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include <json/assertions.h>
+#include <json/value.h>
+#include <json/writer.h>
+#endif // if !defined(JSON_IS_AMALGAMATION)
+#include <algorithm>
+#include <cassert>
+#include <cmath>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+#include <sstream>
+#include <utility>
+
+// Provide implementation equivalent of std::snprintf for older _MSC compilers
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#include <stdarg.h>
+static int msvc_pre1900_c99_vsnprintf(char* outBuf, size_t size,
+                                      const char* format, va_list ap) {
+  int count = -1;
+  if (size != 0)
+    count = _vsnprintf_s(outBuf, size, _TRUNCATE, format, ap);
+  if (count == -1)
+    count = _vscprintf(format, ap);
+  return count;
+}
+
+int JSON_API msvc_pre1900_c99_snprintf(char* outBuf, size_t size,
+                                       const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  const int count = msvc_pre1900_c99_vsnprintf(outBuf, size, format, ap);
+  va_end(ap);
+  return count;
+}
+#endif
+
+// Disable warning C4702 : unreachable code
+#if defined(_MSC_VER)
+#pragma warning(disable : 4702)
+#endif
+
+#define JSON_ASSERT_UNREACHABLE assert(false)
+
+namespace Json {
+template <typename T>
+static std::unique_ptr<T> cloneUnique(const std::unique_ptr<T>& p) {
+  std::unique_ptr<T> r;
+  if (p) {
+    r = std::unique_ptr<T>(new T(*p));
+  }
+  return r;
+}
+
+// This is a walkaround to avoid the static initialization of Value::null.
+// kNull must be word-aligned to avoid crashing on ARM.  We use an alignment of
+// 8 (instead of 4) as a bit of future-proofing.
+#if defined(__ARMEL__)
+#define ALIGNAS(byte_alignment) __attribute__((aligned(byte_alignment)))
+#else
+#define ALIGNAS(byte_alignment)
+#endif
+
+// static
+Value const& Value::nullSingleton() {
+  static Value const nullStatic;
+  return nullStatic;
+}
+
+#if JSON_USE_NULLREF
+// for backwards compatibility, we'll leave these global references around, but
+// DO NOT use them in JSONCPP library code any more!
+// static
+Value const& Value::null = Value::nullSingleton();
+
+// static
+Value const& Value::nullRef = Value::nullSingleton();
+#endif
+
+#if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+template <typename T, typename U>
+static inline bool InRange(double d, T min, U max) {
+  // The casts can lose precision, but we are looking only for
+  // an approximate range. Might fail on edge cases though. ~cdunn
+  return d >= static_cast<double>(min) && d <= static_cast<double>(max);
+}
+#else  // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+static inline double integerToDouble(Json::UInt64 value) {
+  return static_cast<double>(Int64(value / 2)) * 2.0 +
+         static_cast<double>(Int64(value & 1));
+}
+
+template <typename T> static inline double integerToDouble(T value) {
+  return static_cast<double>(value);
+}
+
+template <typename T, typename U>
+static inline bool InRange(double d, T min, U max) {
+  return d >= integerToDouble(min) && d <= integerToDouble(max);
+}
+#endif // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+
+/** Duplicates the specified string value.
+ * @param value Pointer to the string to duplicate. Must be zero-terminated if
+ *              length is "unknown".
+ * @param length Length of the value. if equals to unknown, then it will be
+ *               computed using strlen(value).
+ * @return Pointer on the duplicate instance of string.
+ */
+static inline char* duplicateStringValue(const char* value, size_t length) {
+  // Avoid an integer overflow in the call to malloc below by limiting length
+  // to a sane value.
+  if (length >= static_cast<size_t>(Value::maxInt))
+    length = Value::maxInt - 1;
+
+  auto newString = static_cast<char*>(malloc(length + 1));
+  if (newString == nullptr) {
+    throwRuntimeError("in Json::Value::duplicateStringValue(): "
+                      "Failed to allocate string value buffer");
+  }
+  memcpy(newString, value, length);
+  newString[length] = 0;
+  return newString;
+}
+
+/* Record the length as a prefix.
+ */
+static inline char* duplicateAndPrefixStringValue(const char* value,
+                                                  unsigned int length) {
+  // Avoid an integer overflow in the call to malloc below by limiting length
+  // to a sane value.
+  JSON_ASSERT_MESSAGE(length <= static_cast<unsigned>(Value::maxInt) -
+                                    sizeof(unsigned) - 1U,
+                      "in Json::Value::duplicateAndPrefixStringValue(): "
+                      "length too big for prefixing");
+  size_t actualLength = sizeof(length) + length + 1;
+  auto newString = static_cast<char*>(malloc(actualLength));
+  if (newString == nullptr) {
+    throwRuntimeError("in Json::Value::duplicateAndPrefixStringValue(): "
+                      "Failed to allocate string value buffer");
+  }
+  *reinterpret_cast<unsigned*>(newString) = length;
+  memcpy(newString + sizeof(unsigned), value, length);
+  newString[actualLength - 1U] =
+      0; // to avoid buffer over-run accidents by users later
+  return newString;
+}
+inline static void decodePrefixedString(bool isPrefixed, char const* prefixed,
+                                        unsigned* length, char const** value) {
+  if (!isPrefixed) {
+    *length = static_cast<unsigned>(strlen(prefixed));
+    *value = prefixed;
+  } else {
+    *length = *reinterpret_cast<unsigned const*>(prefixed);
+    *value = prefixed + sizeof(unsigned);
+  }
+}
+/** Free the string duplicated by
+ * duplicateStringValue()/duplicateAndPrefixStringValue().
+ */
+#if JSONCPP_USING_SECURE_MEMORY
+static inline void releasePrefixedStringValue(char* value) {
+  unsigned length = 0;
+  char const* valueDecoded;
+  decodePrefixedString(true, value, &length, &valueDecoded);
+  size_t const size = sizeof(unsigned) + length + 1U;
+  memset(value, 0, size);
+  free(value);
+}
+static inline void releaseStringValue(char* value, unsigned length) {
+  // length==0 => we allocated the strings memory
+  size_t size = (length == 0) ? strlen(value) : length;
+  memset(value, 0, size);
+  free(value);
+}
+#else  // !JSONCPP_USING_SECURE_MEMORY
+static inline void releasePrefixedStringValue(char* value) { free(value); }
+static inline void releaseStringValue(char* value, unsigned) { free(value); }
+#endif // JSONCPP_USING_SECURE_MEMORY
+
+} // namespace Json
+
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// ValueInternals...
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+#if !defined(JSON_IS_AMALGAMATION)
+
+#include "json_valueiterator.inl"
+#endif // if !defined(JSON_IS_AMALGAMATION)
+
+namespace Json {
+
+#if JSON_USE_EXCEPTION
+Exception::Exception(String msg) : msg_(std::move(msg)) {}
+Exception::~Exception() noexcept = default;
+char const* Exception::what() const noexcept { return msg_.c_str(); }
+RuntimeError::RuntimeError(String const& msg) : Exception(msg) {}
+LogicError::LogicError(String const& msg) : Exception(msg) {}
+JSONCPP_NORETURN void throwRuntimeError(String const& msg) {
+  throw RuntimeError(msg);
+}
+JSONCPP_NORETURN void throwLogicError(String const& msg) {
+  throw LogicError(msg);
+}
+#else // !JSON_USE_EXCEPTION
+JSONCPP_NORETURN void throwRuntimeError(String const& msg) {
+  std::cerr << msg << std::endl;
+  abort();
+}
+JSONCPP_NORETURN void throwLogicError(String const& msg) {
+  std::cerr << msg << std::endl;
+  abort();
+}
+#endif
+
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// class Value::CZString
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+
+// Notes: policy_ indicates if the string was allocated when
+// a string is stored.
+
+Value::CZString::CZString(ArrayIndex index) : cstr_(nullptr), index_(index) {}
+
+Value::CZString::CZString(char const* str, unsigned length,
+                          DuplicationPolicy allocate)
+    : cstr_(str) {
+  // allocate != duplicate
+  storage_.policy_ = allocate & 0x3;
+  storage_.length_ = length & 0x3FFFFFFF;
+}
+
+Value::CZString::CZString(const CZString& other) {
+  cstr_ = (other.storage_.policy_ != noDuplication && other.cstr_ != nullptr
+               ? duplicateStringValue(other.cstr_, other.storage_.length_)
+               : other.cstr_);
+  storage_.policy_ =
+      static_cast<unsigned>(
+          other.cstr_
+              ? (static_cast<DuplicationPolicy>(other.storage_.policy_) ==
+                         noDuplication
+                     ? noDuplication
+                     : duplicate)
+              : static_cast<DuplicationPolicy>(other.storage_.policy_)) &
+      3U;
+  storage_.length_ = other.storage_.length_;
+}
+
+Value::CZString::CZString(CZString&& other) noexcept
+    : cstr_(other.cstr_), index_(other.index_) {
+  other.cstr_ = nullptr;
+}
+
+Value::CZString::~CZString() {
+  if (cstr_ && storage_.policy_ == duplicate) {
+    releaseStringValue(const_cast<char*>(cstr_),
+                       storage_.length_ + 1U); // +1 for null terminating
+                                               // character for sake of
+                                               // completeness but not actually
+                                               // necessary
+  }
+}
+
+void Value::CZString::swap(CZString& other) {
+  std::swap(cstr_, other.cstr_);
+  std::swap(index_, other.index_);
+}
+
+Value::CZString& Value::CZString::operator=(const CZString& other) {
+  cstr_ = other.cstr_;
+  index_ = other.index_;
+  return *this;
+}
+
+Value::CZString& Value::CZString::operator=(CZString&& other) noexcept {
+  cstr_ = other.cstr_;
+  index_ = other.index_;
+  other.cstr_ = nullptr;
+  return *this;
+}
+
+bool Value::CZString::operator<(const CZString& other) const {
+  if (!cstr_)
+    return index_ < other.index_;
+  // return strcmp(cstr_, other.cstr_) < 0;
+  // Assume both are strings.
+  unsigned this_len = this->storage_.length_;
+  unsigned other_len = other.storage_.length_;
+  unsigned min_len = std::min<unsigned>(this_len, other_len);
+  JSON_ASSERT(this->cstr_ && other.cstr_);
+  int comp = memcmp(this->cstr_, other.cstr_, min_len);
+  if (comp < 0)
+    return true;
+  if (comp > 0)
+    return false;
+  return (this_len < other_len);
+}
+
+bool Value::CZString::operator==(const CZString& other) const {
+  if (!cstr_)
+    return index_ == other.index_;
+  // return strcmp(cstr_, other.cstr_) == 0;
+  // Assume both are strings.
+  unsigned this_len = this->storage_.length_;
+  unsigned other_len = other.storage_.length_;
+  if (this_len != other_len)
+    return false;
+  JSON_ASSERT(this->cstr_ && other.cstr_);
+  int comp = memcmp(this->cstr_, other.cstr_, this_len);
+  return comp == 0;
+}
+
+ArrayIndex Value::CZString::index() const { return index_; }
+
+// const char* Value::CZString::c_str() const { return cstr_; }
+const char* Value::CZString::data() const { return cstr_; }
+unsigned Value::CZString::length() const { return storage_.length_; }
+bool Value::CZString::isStaticString() const {
+  return storage_.policy_ == noDuplication;
+}
+
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// class Value::Value
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+
+/*! \internal Default constructor initialization must be equivalent to:
+ * memset( this, 0, sizeof(Value) )
+ * This optimization is used in ValueInternalMap fast allocator.
+ */
+Value::Value(ValueType type) {
+  static char const emptyString[] = "";
+  initBasic(type);
+  switch (type) {
+  case nullValue:
+    break;
+  case intValue:
+  case uintValue:
+    value_.int_ = 0;
+    break;
+  case realValue:
+    value_.real_ = 0.0;
+    break;
+  case stringValue:
+    // allocated_ == false, so this is safe.
+    value_.string_ = const_cast<char*>(static_cast<char const*>(emptyString));
+    break;
+  case arrayValue:
+  case objectValue:
+    value_.map_ = new ObjectValues();
+    break;
+  case booleanValue:
+    value_.bool_ = false;
+    break;
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+}
+
+Value::Value(Int value) {
+  initBasic(intValue);
+  value_.int_ = value;
+}
+
+Value::Value(UInt value) {
+  initBasic(uintValue);
+  value_.uint_ = value;
+}
+#if defined(JSON_HAS_INT64)
+Value::Value(Int64 value) {
+  initBasic(intValue);
+  value_.int_ = value;
+}
+Value::Value(UInt64 value) {
+  initBasic(uintValue);
+  value_.uint_ = value;
+}
+#endif // defined(JSON_HAS_INT64)
+
+Value::Value(double value) {
+  initBasic(realValue);
+  value_.real_ = value;
+}
+
+Value::Value(const char* value) {
+  initBasic(stringValue, true);
+  JSON_ASSERT_MESSAGE(value != nullptr,
+                      "Null Value Passed to Value Constructor");
+  value_.string_ = duplicateAndPrefixStringValue(
+      value, static_cast<unsigned>(strlen(value)));
+}
+
+Value::Value(const char* begin, const char* end) {
+  initBasic(stringValue, true);
+  value_.string_ =
+      duplicateAndPrefixStringValue(begin, static_cast<unsigned>(end - begin));
+}
+
+Value::Value(const String& value) {
+  initBasic(stringValue, true);
+  value_.string_ = duplicateAndPrefixStringValue(
+      value.data(), static_cast<unsigned>(value.length()));
+}
+
+Value::Value(const StaticString& value) {
+  initBasic(stringValue);
+  value_.string_ = const_cast<char*>(value.c_str());
+}
+
+Value::Value(bool value) {
+  initBasic(booleanValue);
+  value_.bool_ = value;
+}
+
+Value::Value(const Value& other) {
+  dupPayload(other);
+  dupMeta(other);
+}
+
+Value::Value(Value&& other) noexcept {
+  initBasic(nullValue);
+  swap(other);
+}
+
+Value::~Value() {
+  releasePayload();
+  value_.uint_ = 0;
+}
+
+Value& Value::operator=(const Value& other) {
+  Value(other).swap(*this);
+  return *this;
+}
+
+Value& Value::operator=(Value&& other) noexcept {
+  other.swap(*this);
+  return *this;
+}
+
+void Value::swapPayload(Value& other) {
+  std::swap(bits_, other.bits_);
+  std::swap(value_, other.value_);
+}
+
+void Value::copyPayload(const Value& other) {
+  releasePayload();
+  dupPayload(other);
+}
+
+void Value::swap(Value& other) {
+  swapPayload(other);
+  std::swap(comments_, other.comments_);
+  std::swap(start_, other.start_);
+  std::swap(limit_, other.limit_);
+}
+
+void Value::copy(const Value& other) {
+  copyPayload(other);
+  dupMeta(other);
+}
+
+ValueType Value::type() const {
+  return static_cast<ValueType>(bits_.value_type_);
+}
+
+int Value::compare(const Value& other) const {
+  if (*this < other)
+    return -1;
+  if (*this > other)
+    return 1;
+  return 0;
+}
+
+bool Value::operator<(const Value& other) const {
+  int typeDelta = type() - other.type();
+  if (typeDelta)
+    return typeDelta < 0;
+  switch (type()) {
+  case nullValue:
+    return false;
+  case intValue:
+    return value_.int_ < other.value_.int_;
+  case uintValue:
+    return value_.uint_ < other.value_.uint_;
+  case realValue:
+    return value_.real_ < other.value_.real_;
+  case booleanValue:
+    return value_.bool_ < other.value_.bool_;
+  case stringValue: {
+    if ((value_.string_ == nullptr) || (other.value_.string_ == nullptr)) {
+      return other.value_.string_ != nullptr;
+    }
+    unsigned this_len;
+    unsigned other_len;
+    char const* this_str;
+    char const* other_str;
+    decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                         &this_str);
+    decodePrefixedString(other.isAllocated(), other.value_.string_, &other_len,
+                         &other_str);
+    unsigned min_len = std::min<unsigned>(this_len, other_len);
+    JSON_ASSERT(this_str && other_str);
+    int comp = memcmp(this_str, other_str, min_len);
+    if (comp < 0)
+      return true;
+    if (comp > 0)
+      return false;
+    return (this_len < other_len);
+  }
+  case arrayValue:
+  case objectValue: {
+    auto thisSize = value_.map_->size();
+    auto otherSize = other.value_.map_->size();
+    if (thisSize != otherSize)
+      return thisSize < otherSize;
+    return (*value_.map_) < (*other.value_.map_);
+  }
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+  return false; // unreachable
+}
+
+bool Value::operator<=(const Value& other) const { return !(other < *this); }
+
+bool Value::operator>=(const Value& other) const { return !(*this < other); }
+
+bool Value::operator>(const Value& other) const { return other < *this; }
+
+bool Value::operator==(const Value& other) const {
+  if (type() != other.type())
+    return false;
+  switch (type()) {
+  case nullValue:
+    return true;
+  case intValue:
+    return value_.int_ == other.value_.int_;
+  case uintValue:
+    return value_.uint_ == other.value_.uint_;
+  case realValue:
+    return value_.real_ == other.value_.real_;
+  case booleanValue:
+    return value_.bool_ == other.value_.bool_;
+  case stringValue: {
+    if ((value_.string_ == nullptr) || (other.value_.string_ == nullptr)) {
+      return (value_.string_ == other.value_.string_);
+    }
+    unsigned this_len;
+    unsigned other_len;
+    char const* this_str;
+    char const* other_str;
+    decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                         &this_str);
+    decodePrefixedString(other.isAllocated(), other.value_.string_, &other_len,
+                         &other_str);
+    if (this_len != other_len)
+      return false;
+    JSON_ASSERT(this_str && other_str);
+    int comp = memcmp(this_str, other_str, this_len);
+    return comp == 0;
+  }
+  case arrayValue:
+  case objectValue:
+    return value_.map_->size() == other.value_.map_->size() &&
+           (*value_.map_) == (*other.value_.map_);
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+  return false; // unreachable
+}
+
+bool Value::operator!=(const Value& other) const { return !(*this == other); }
+
+const char* Value::asCString() const {
+  JSON_ASSERT_MESSAGE(type() == stringValue,
+                      "in Json::Value::asCString(): requires stringValue");
+  if (value_.string_ == nullptr)
+    return nullptr;
+  unsigned this_len;
+  char const* this_str;
+  decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                       &this_str);
+  return this_str;
+}
+
+#if JSONCPP_USING_SECURE_MEMORY
+unsigned Value::getCStringLength() const {
+  JSON_ASSERT_MESSAGE(type() == stringValue,
+                      "in Json::Value::asCString(): requires stringValue");
+  if (value_.string_ == 0)
+    return 0;
+  unsigned this_len;
+  char const* this_str;
+  decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                       &this_str);
+  return this_len;
+}
+#endif
+
+bool Value::getString(char const** begin, char const** end) const {
+  if (type() != stringValue)
+    return false;
+  if (value_.string_ == nullptr)
+    return false;
+  unsigned length;
+  decodePrefixedString(this->isAllocated(), this->value_.string_, &length,
+                       begin);
+  *end = *begin + length;
+  return true;
+}
+
+String Value::asString() const {
+  switch (type()) {
+  case nullValue:
+    return "";
+  case stringValue: {
+    if (value_.string_ == nullptr)
+      return "";
+    unsigned this_len;
+    char const* this_str;
+    decodePrefixedString(this->isAllocated(), this->value_.string_, &this_len,
+                         &this_str);
+    return String(this_str, this_len);
+  }
+  case booleanValue:
+    return value_.bool_ ? "true" : "false";
+  case intValue:
+    return valueToString(value_.int_);
+  case uintValue:
+    return valueToString(value_.uint_);
+  case realValue:
+    return valueToString(value_.real_);
+  default:
+    JSON_FAIL_MESSAGE("Type is not convertible to string");
+  }
+}
+
+Value::Int Value::asInt() const {
+  switch (type()) {
+  case intValue:
+    JSON_ASSERT_MESSAGE(isInt(), "LargestInt out of Int range");
+    return Int(value_.int_);
+  case uintValue:
+    JSON_ASSERT_MESSAGE(isInt(), "LargestUInt out of Int range");
+    return Int(value_.uint_);
+  case realValue:
+    JSON_ASSERT_MESSAGE(InRange(value_.real_, minInt, maxInt),
+                        "double out of Int range");
+    return Int(value_.real_);
+  case nullValue:
+    return 0;
+  case booleanValue:
+    return value_.bool_ ? 1 : 0;
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to Int.");
+}
+
+Value::UInt Value::asUInt() const {
+  switch (type()) {
+  case intValue:
+    JSON_ASSERT_MESSAGE(isUInt(), "LargestInt out of UInt range");
+    return UInt(value_.int_);
+  case uintValue:
+    JSON_ASSERT_MESSAGE(isUInt(), "LargestUInt out of UInt range");
+    return UInt(value_.uint_);
+  case realValue:
+    JSON_ASSERT_MESSAGE(InRange(value_.real_, 0, maxUInt),
+                        "double out of UInt range");
+    return UInt(value_.real_);
+  case nullValue:
+    return 0;
+  case booleanValue:
+    return value_.bool_ ? 1 : 0;
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to UInt.");
+}
+
+#if defined(JSON_HAS_INT64)
+
+Value::Int64 Value::asInt64() const {
+  switch (type()) {
+  case intValue:
+    return Int64(value_.int_);
+  case uintValue:
+    JSON_ASSERT_MESSAGE(isInt64(), "LargestUInt out of Int64 range");
+    return Int64(value_.uint_);
+  case realValue:
+    JSON_ASSERT_MESSAGE(InRange(value_.real_, minInt64, maxInt64),
+                        "double out of Int64 range");
+    return Int64(value_.real_);
+  case nullValue:
+    return 0;
+  case booleanValue:
+    return value_.bool_ ? 1 : 0;
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to Int64.");
+}
+
+Value::UInt64 Value::asUInt64() const {
+  switch (type()) {
+  case intValue:
+    JSON_ASSERT_MESSAGE(isUInt64(), "LargestInt out of UInt64 range");
+    return UInt64(value_.int_);
+  case uintValue:
+    return UInt64(value_.uint_);
+  case realValue:
+    JSON_ASSERT_MESSAGE(InRange(value_.real_, 0, maxUInt64),
+                        "double out of UInt64 range");
+    return UInt64(value_.real_);
+  case nullValue:
+    return 0;
+  case booleanValue:
+    return value_.bool_ ? 1 : 0;
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to UInt64.");
+}
+#endif // if defined(JSON_HAS_INT64)
+
+LargestInt Value::asLargestInt() const {
+#if defined(JSON_NO_INT64)
+  return asInt();
+#else
+  return asInt64();
+#endif
+}
+
+LargestUInt Value::asLargestUInt() const {
+#if defined(JSON_NO_INT64)
+  return asUInt();
+#else
+  return asUInt64();
+#endif
+}
+
+double Value::asDouble() const {
+  switch (type()) {
+  case intValue:
+    return static_cast<double>(value_.int_);
+  case uintValue:
+#if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+    return static_cast<double>(value_.uint_);
+#else  // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+    return integerToDouble(value_.uint_);
+#endif // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+  case realValue:
+    return value_.real_;
+  case nullValue:
+    return 0.0;
+  case booleanValue:
+    return value_.bool_ ? 1.0 : 0.0;
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to double.");
+}
+
+float Value::asFloat() const {
+  switch (type()) {
+  case intValue:
+    return static_cast<float>(value_.int_);
+  case uintValue:
+#if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+    return static_cast<float>(value_.uint_);
+#else  // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+    // This can fail (silently?) if the value is bigger than MAX_FLOAT.
+    return static_cast<float>(integerToDouble(value_.uint_));
+#endif // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
+  case realValue:
+    return static_cast<float>(value_.real_);
+  case nullValue:
+    return 0.0;
+  case booleanValue:
+    return value_.bool_ ? 1.0F : 0.0F;
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to float.");
+}
+
+bool Value::asBool() const {
+  switch (type()) {
+  case booleanValue:
+    return value_.bool_;
+  case nullValue:
+    return false;
+  case intValue:
+    return value_.int_ != 0;
+  case uintValue:
+    return value_.uint_ != 0;
+  case realValue: {
+    // According to JavaScript language zero or NaN is regarded as false
+    const auto value_classification = std::fpclassify(value_.real_);
+    return value_classification != FP_ZERO && value_classification != FP_NAN;
+  }
+  default:
+    break;
+  }
+  JSON_FAIL_MESSAGE("Value is not convertible to bool.");
+}
+
+bool Value::isConvertibleTo(ValueType other) const {
+  switch (other) {
+  case nullValue:
+    return (isNumeric() && asDouble() == 0.0) ||
+           (type() == booleanValue && !value_.bool_) ||
+           (type() == stringValue && asString().empty()) ||
+           (type() == arrayValue && value_.map_->empty()) ||
+           (type() == objectValue && value_.map_->empty()) ||
+           type() == nullValue;
+  case intValue:
+    return isInt() ||
+           (type() == realValue && InRange(value_.real_, minInt, maxInt)) ||
+           type() == booleanValue || type() == nullValue;
+  case uintValue:
+    return isUInt() ||
+           (type() == realValue && InRange(value_.real_, 0, maxUInt)) ||
+           type() == booleanValue || type() == nullValue;
+  case realValue:
+    return isNumeric() || type() == booleanValue || type() == nullValue;
+  case booleanValue:
+    return isNumeric() || type() == booleanValue || type() == nullValue;
+  case stringValue:
+    return isNumeric() || type() == booleanValue || type() == stringValue ||
+           type() == nullValue;
+  case arrayValue:
+    return type() == arrayValue || type() == nullValue;
+  case objectValue:
+    return type() == objectValue || type() == nullValue;
+  }
+  JSON_ASSERT_UNREACHABLE;
+  return false;
+}
+
+/// Number of values in array or object
+ArrayIndex Value::size() const {
+  switch (type()) {
+  case nullValue:
+  case intValue:
+  case uintValue:
+  case realValue:
+  case booleanValue:
+  case stringValue:
+    return 0;
+  case arrayValue: // size of the array is highest index + 1
+    if (!value_.map_->empty()) {
+      ObjectValues::const_iterator itLast = value_.map_->end();
+      --itLast;
+      return (*itLast).first.index() + 1;
+    }
+    return 0;
+  case objectValue:
+    return ArrayIndex(value_.map_->size());
+  }
+  JSON_ASSERT_UNREACHABLE;
+  return 0; // unreachable;
+}
+
+bool Value::empty() const {
+  if (isNull() || isArray() || isObject())
+    return size() == 0U;
+  return false;
+}
+
+Value::operator bool() const { return !isNull(); }
+
+void Value::clear() {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue ||
+                          type() == objectValue,
+                      "in Json::Value::clear(): requires complex value");
+  start_ = 0;
+  limit_ = 0;
+  switch (type()) {
+  case arrayValue:
+  case objectValue:
+    value_.map_->clear();
+    break;
+  default:
+    break;
+  }
+}
+
+void Value::resize(ArrayIndex newSize) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue,
+                      "in Json::Value::resize(): requires arrayValue");
+  if (type() == nullValue)
+    *this = Value(arrayValue);
+  ArrayIndex oldSize = size();
+  if (newSize == 0)
+    clear();
+  else if (newSize > oldSize)
+    for (ArrayIndex i = oldSize; i < newSize; ++i)
+      (*this)[i];
+  else {
+    for (ArrayIndex index = newSize; index < oldSize; ++index) {
+      value_.map_->erase(index);
+    }
+    JSON_ASSERT(size() == newSize);
+  }
+}
+
+Value& Value::operator[](ArrayIndex index) {
+  JSON_ASSERT_MESSAGE(
+      type() == nullValue || type() == arrayValue,
+      "in Json::Value::operator[](ArrayIndex): requires arrayValue");
+  if (type() == nullValue)
+    *this = Value(arrayValue);
+  CZString key(index);
+  auto it = value_.map_->lower_bound(key);
+  if (it != value_.map_->end() && (*it).first == key)
+    return (*it).second;
+
+  ObjectValues::value_type defaultValue(key, nullSingleton());
+  it = value_.map_->insert(it, defaultValue);
+  return (*it).second;
+}
+
+Value& Value::operator[](int index) {
+  JSON_ASSERT_MESSAGE(
+      index >= 0,
+      "in Json::Value::operator[](int index): index cannot be negative");
+  return (*this)[ArrayIndex(index)];
+}
+
+const Value& Value::operator[](ArrayIndex index) const {
+  JSON_ASSERT_MESSAGE(
+      type() == nullValue || type() == arrayValue,
+      "in Json::Value::operator[](ArrayIndex)const: requires arrayValue");
+  if (type() == nullValue)
+    return nullSingleton();
+  CZString key(index);
+  ObjectValues::const_iterator it = value_.map_->find(key);
+  if (it == value_.map_->end())
+    return nullSingleton();
+  return (*it).second;
+}
+
+const Value& Value::operator[](int index) const {
+  JSON_ASSERT_MESSAGE(
+      index >= 0,
+      "in Json::Value::operator[](int index) const: index cannot be negative");
+  return (*this)[ArrayIndex(index)];
+}
+
+void Value::initBasic(ValueType type, bool allocated) {
+  setType(type);
+  setIsAllocated(allocated);
+  comments_ = Comments{};
+  start_ = 0;
+  limit_ = 0;
+}
+
+void Value::dupPayload(const Value& other) {
+  setType(other.type());
+  setIsAllocated(false);
+  switch (type()) {
+  case nullValue:
+  case intValue:
+  case uintValue:
+  case realValue:
+  case booleanValue:
+    value_ = other.value_;
+    break;
+  case stringValue:
+    if (other.value_.string_ && other.isAllocated()) {
+      unsigned len;
+      char const* str;
+      decodePrefixedString(other.isAllocated(), other.value_.string_, &len,
+                           &str);
+      value_.string_ = duplicateAndPrefixStringValue(str, len);
+      setIsAllocated(true);
+    } else {
+      value_.string_ = other.value_.string_;
+    }
+    break;
+  case arrayValue:
+  case objectValue:
+    value_.map_ = new ObjectValues(*other.value_.map_);
+    break;
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+}
+
+void Value::releasePayload() {
+  switch (type()) {
+  case nullValue:
+  case intValue:
+  case uintValue:
+  case realValue:
+  case booleanValue:
+    break;
+  case stringValue:
+    if (isAllocated())
+      releasePrefixedStringValue(value_.string_);
+    break;
+  case arrayValue:
+  case objectValue:
+    delete value_.map_;
+    break;
+  default:
+    JSON_ASSERT_UNREACHABLE;
+  }
+}
+
+void Value::dupMeta(const Value& other) {
+  comments_ = other.comments_;
+  start_ = other.start_;
+  limit_ = other.limit_;
+}
+
+// Access an object value by name, create a null member if it does not exist.
+// @pre Type of '*this' is object or null.
+// @param key is null-terminated.
+Value& Value::resolveReference(const char* key) {
+  JSON_ASSERT_MESSAGE(
+      type() == nullValue || type() == objectValue,
+      "in Json::Value::resolveReference(): requires objectValue");
+  if (type() == nullValue)
+    *this = Value(objectValue);
+  CZString actualKey(key, static_cast<unsigned>(strlen(key)),
+                     CZString::noDuplication); // NOTE!
+  auto it = value_.map_->lower_bound(actualKey);
+  if (it != value_.map_->end() && (*it).first == actualKey)
+    return (*it).second;
+
+  ObjectValues::value_type defaultValue(actualKey, nullSingleton());
+  it = value_.map_->insert(it, defaultValue);
+  Value& value = (*it).second;
+  return value;
+}
+
+// @param key is not null-terminated.
+Value& Value::resolveReference(char const* key, char const* end) {
+  JSON_ASSERT_MESSAGE(
+      type() == nullValue || type() == objectValue,
+      "in Json::Value::resolveReference(key, end): requires objectValue");
+  if (type() == nullValue)
+    *this = Value(objectValue);
+  CZString actualKey(key, static_cast<unsigned>(end - key),
+                     CZString::duplicateOnCopy);
+  auto it = value_.map_->lower_bound(actualKey);
+  if (it != value_.map_->end() && (*it).first == actualKey)
+    return (*it).second;
+
+  ObjectValues::value_type defaultValue(actualKey, nullSingleton());
+  it = value_.map_->insert(it, defaultValue);
+  Value& value = (*it).second;
+  return value;
+}
+
+Value Value::get(ArrayIndex index, const Value& defaultValue) const {
+  const Value* value = &((*this)[index]);
+  return value == &nullSingleton() ? defaultValue : *value;
+}
+
+bool Value::isValidIndex(ArrayIndex index) const { return index < size(); }
+
+Value const* Value::find(char const* begin, char const* end) const {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == objectValue,
+                      "in Json::Value::find(begin, end): requires "
+                      "objectValue or nullValue");
+  if (type() == nullValue)
+    return nullptr;
+  CZString actualKey(begin, static_cast<unsigned>(end - begin),
+                     CZString::noDuplication);
+  ObjectValues::const_iterator it = value_.map_->find(actualKey);
+  if (it == value_.map_->end())
+    return nullptr;
+  return &(*it).second;
+}
+Value* Value::demand(char const* begin, char const* end) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == objectValue,
+                      "in Json::Value::demand(begin, end): requires "
+                      "objectValue or nullValue");
+  return &resolveReference(begin, end);
+}
+const Value& Value::operator[](const char* key) const {
+  Value const* found = find(key, key + strlen(key));
+  if (!found)
+    return nullSingleton();
+  return *found;
+}
+Value const& Value::operator[](const String& key) const {
+  Value const* found = find(key.data(), key.data() + key.length());
+  if (!found)
+    return nullSingleton();
+  return *found;
+}
+
+Value& Value::operator[](const char* key) {
+  return resolveReference(key, key + strlen(key));
+}
+
+Value& Value::operator[](const String& key) {
+  return resolveReference(key.data(), key.data() + key.length());
+}
+
+Value& Value::operator[](const StaticString& key) {
+  return resolveReference(key.c_str());
+}
+
+Value& Value::append(const Value& value) { return append(Value(value)); }
+
+Value& Value::append(Value&& value) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue,
+                      "in Json::Value::append: requires arrayValue");
+  if (type() == nullValue) {
+    *this = Value(arrayValue);
+  }
+  return this->value_.map_->emplace(size(), std::move(value)).first->second;
+}
+
+bool Value::insert(ArrayIndex index, const Value& newValue) {
+  return insert(index, Value(newValue));
+}
+
+bool Value::insert(ArrayIndex index, Value&& newValue) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == arrayValue,
+                      "in Json::Value::insert: requires arrayValue");
+  ArrayIndex length = size();
+  if (index > length) {
+    return false;
+  }
+  for (ArrayIndex i = length; i > index; i--) {
+    (*this)[i] = std::move((*this)[i - 1]);
+  }
+  (*this)[index] = std::move(newValue);
+  return true;
+}
+
+Value Value::get(char const* begin, char const* end,
+                 Value const& defaultValue) const {
+  Value const* found = find(begin, end);
+  return !found ? defaultValue : *found;
+}
+Value Value::get(char const* key, Value const& defaultValue) const {
+  return get(key, key + strlen(key), defaultValue);
+}
+Value Value::get(String const& key, Value const& defaultValue) const {
+  return get(key.data(), key.data() + key.length(), defaultValue);
+}
+
+bool Value::removeMember(const char* begin, const char* end, Value* removed) {
+  if (type() != objectValue) {
+    return false;
+  }
+  CZString actualKey(begin, static_cast<unsigned>(end - begin),
+                     CZString::noDuplication);
+  auto it = value_.map_->find(actualKey);
+  if (it == value_.map_->end())
+    return false;
+  if (removed)
+    *removed = std::move(it->second);
+  value_.map_->erase(it);
+  return true;
+}
+bool Value::removeMember(const char* key, Value* removed) {
+  return removeMember(key, key + strlen(key), removed);
+}
+bool Value::removeMember(String const& key, Value* removed) {
+  return removeMember(key.data(), key.data() + key.length(), removed);
+}
+void Value::removeMember(const char* key) {
+  JSON_ASSERT_MESSAGE(type() == nullValue || type() == objectValue,
+                      "in Json::Value::removeMember(): requires objectValue");
+  if (type() == nullValue)
+    return;
+
+  CZString actualKey(key, unsigned(strlen(key)), CZString::noDuplication);
+  value_.map_->erase(actualKey);
+}
+void Value::removeMember(const String& key) { removeMember(key.c_str()); }
+
+bool Value::removeIndex(ArrayIndex index, Value* removed) {
+  if (type() != arrayValue) {
+    return false;
+  }
+  CZString key(index);
+  auto it = value_.map_->find(key);
+  if (it == value_.map_->end()) {
+    return false;
+  }
+  if (removed)
+    *removed = it->second;
+  ArrayIndex oldSize = size();
+  // shift left all items left, into the place of the "removed"
+  for (ArrayIndex i = index; i < (oldSize - 1); ++i) {
+    CZString keey(i);
+    (*value_.map_)[keey] = (*this)[i + 1];
+  }
+  // erase the last one ("leftover")
+  CZString keyLast(oldSize - 1);
+  auto itLast = value_.map_->find(keyLast);
+  value_.map_->erase(itLast);
+  return true;
+}
+
+bool Value::isMember(char const* begin, char const* end) const {
+  Value const* value = find(begin, end);
+  return nullptr != value;
+}
+bool Value::isMember(char const* key) const {
+  return isMember(key, key + strlen(key));
+}
+bool Value::isMember(String const& key) const {
+  return isMember(key.data(), key.data() + key.length());
+}
+
+Value::Members Value::getMemberNames() const {
+  JSON_ASSERT_MESSAGE(
+      type() == nullValue || type() == objectValue,
+      "in Json::Value::getMemberNames(), value must be objectValue");
+  if (type() == nullValue)
+    return Value::Members();
+  Members members;
+  members.reserve(value_.map_->size());
+  ObjectValues::const_iterator it = value_.map_->begin();
+  ObjectValues::const_iterator itEnd = value_.map_->end();
+  for (; it != itEnd; ++it) {
+    members.push_back(String((*it).first.data(), (*it).first.length()));
+  }
+  return members;
+}
+
+static bool IsIntegral(double d) {
+  double integral_part;
+  return modf(d, &integral_part) == 0.0;
+}
+
+bool Value::isNull() const { return type() == nullValue; }
+
+bool Value::isBool() const { return type() == booleanValue; }
+
+bool Value::isInt() const {
+  switch (type()) {
+  case intValue:
+#if defined(JSON_HAS_INT64)
+    return value_.int_ >= minInt && value_.int_ <= maxInt;
+#else
+    return true;
+#endif
+  case uintValue:
+    return value_.uint_ <= UInt(maxInt);
+  case realValue:
+    return value_.real_ >= minInt && value_.real_ <= maxInt &&
+           IsIntegral(value_.real_);
+  default:
+    break;
+  }
+  return false;
+}
+
+bool Value::isUInt() const {
+  switch (type()) {
+  case intValue:
+#if defined(JSON_HAS_INT64)
+    return value_.int_ >= 0 && LargestUInt(value_.int_) <= LargestUInt(maxUInt);
+#else
+    return value_.int_ >= 0;
+#endif
+  case uintValue:
+#if defined(JSON_HAS_INT64)
+    return value_.uint_ <= maxUInt;
+#else
+    return true;
+#endif
+  case realValue:
+    return value_.real_ >= 0 && value_.real_ <= maxUInt &&
+           IsIntegral(value_.real_);
+  default:
+    break;
+  }
+  return false;
+}
+
+bool Value::isInt64() const {
+#if defined(JSON_HAS_INT64)
+  switch (type()) {
+  case intValue:
+    return true;
+  case uintValue:
+    return value_.uint_ <= UInt64(maxInt64);
+  case realValue:
+    // Note that maxInt64 (= 2^63 - 1) is not exactly representable as a
+    // double, so double(maxInt64) will be rounded up to 2^63. Therefore we
+    // require the value to be strictly less than the limit.
+    return value_.real_ >= double(minInt64) &&
+           value_.real_ < double(maxInt64) && IsIntegral(value_.real_);
+  default:
+    break;
+  }
+#endif // JSON_HAS_INT64
+  return false;
+}
+
+bool Value::isUInt64() const {
+#if defined(JSON_HAS_INT64)
+  switch (type()) {
+  case intValue:
+    return value_.int_ >= 0;
+  case uintValue:
+    return true;
+  case realValue:
+    // Note that maxUInt64 (= 2^64 - 1) is not exactly representable as a
+    // double, so double(maxUInt64) will be rounded up to 2^64. Therefore we
+    // require the value to be strictly less than the limit.
+    return value_.real_ >= 0 && value_.real_ < maxUInt64AsDouble &&
+           IsIntegral(value_.real_);
+  default:
+    break;
+  }
+#endif // JSON_HAS_INT64
+  return false;
+}
+
+bool Value::isIntegral() const {
+  switch (type()) {
+  case intValue:
+  case uintValue:
+    return true;
+  case realValue:
+#if defined(JSON_HAS_INT64)
+    // Note that maxUInt64 (= 2^64 - 1) is not exactly representable as a
+    // double, so double(maxUInt64) will be rounded up to 2^64. Therefore we
+    // require the value to be strictly less than the limit.
+    return value_.real_ >= double(minInt64) &&
+           value_.real_ < maxUInt64AsDouble && IsIntegral(value_.real_);
+#else
+    return value_.real_ >= minInt && value_.real_ <= maxUInt &&
+           IsIntegral(value_.real_);
+#endif // JSON_HAS_INT64
+  default:
+    break;
+  }
+  return false;
+}
+
+bool Value::isDouble() const {
+  return type() == intValue || type() == uintValue || type() == realValue;
+}
+
+bool Value::isNumeric() const { return isDouble(); }
+
+bool Value::isString() const { return type() == stringValue; }
+
+bool Value::isArray() const { return type() == arrayValue; }
+
+bool Value::isObject() const { return type() == objectValue; }
+
+Value::Comments::Comments(const Comments& that)
+    : ptr_{cloneUnique(that.ptr_)} {}
+
+Value::Comments::Comments(Comments&& that) noexcept
+    : ptr_{std::move(that.ptr_)} {}
+
+Value::Comments& Value::Comments::operator=(const Comments& that) {
+  ptr_ = cloneUnique(that.ptr_);
+  return *this;
+}
+
+Value::Comments& Value::Comments::operator=(Comments&& that) noexcept {
+  ptr_ = std::move(that.ptr_);
+  return *this;
+}
+
+bool Value::Comments::has(CommentPlacement slot) const {
+  return ptr_ && !(*ptr_)[slot].empty();
+}
+
+String Value::Comments::get(CommentPlacement slot) const {
+  if (!ptr_)
+    return {};
+  return (*ptr_)[slot];
+}
+
+void Value::Comments::set(CommentPlacement slot, String comment) {
+  if (slot >= CommentPlacement::numberOfCommentPlacement)
+    return;
+  if (!ptr_)
+    ptr_ = std::unique_ptr<Array>(new Array());
+  (*ptr_)[slot] = std::move(comment);
+}
+
+void Value::setComment(String comment, CommentPlacement placement) {
+  if (!comment.empty() && (comment.back() == '\n')) {
+    // Always discard trailing newline, to aid indentation.
+    comment.pop_back();
+  }
+  JSON_ASSERT(!comment.empty());
+  JSON_ASSERT_MESSAGE(
+      comment[0] == '\0' || comment[0] == '/',
+      "in Json::Value::setComment(): Comments must start with /");
+  comments_.set(placement, std::move(comment));
+}
+
+bool Value::hasComment(CommentPlacement placement) const {
+  return comments_.has(placement);
+}
+
+String Value::getComment(CommentPlacement placement) const {
+  return comments_.get(placement);
+}
+
+void Value::setOffsetStart(ptrdiff_t start) { start_ = start; }
+
+void Value::setOffsetLimit(ptrdiff_t limit) { limit_ = limit; }
+
+ptrdiff_t Value::getOffsetStart() const { return start_; }
+
+ptrdiff_t Value::getOffsetLimit() const { return limit_; }
+
+String Value::toStyledString() const {
+  StreamWriterBuilder builder;
+
+  String out = this->hasComment(commentBefore) ? "\n" : "";
+  out += Json::writeString(builder, *this);
+  out += '\n';
+
+  return out;
+}
+
+Value::const_iterator Value::begin() const {
+  switch (type()) {
+  case arrayValue:
+  case objectValue:
+    if (value_.map_)
+      return const_iterator(value_.map_->begin());
+    break;
+  default:
+    break;
+  }
+  return {};
+}
+
+Value::const_iterator Value::end() const {
+  switch (type()) {
+  case arrayValue:
+  case objectValue:
+    if (value_.map_)
+      return const_iterator(value_.map_->end());
+    break;
+  default:
+    break;
+  }
+  return {};
+}
+
+Value::iterator Value::begin() {
+  switch (type()) {
+  case arrayValue:
+  case objectValue:
+    if (value_.map_)
+      return iterator(value_.map_->begin());
+    break;
+  default:
+    break;
+  }
+  return iterator();
+}
+
+Value::iterator Value::end() {
+  switch (type()) {
+  case arrayValue:
+  case objectValue:
+    if (value_.map_)
+      return iterator(value_.map_->end());
+    break;
+  default:
+    break;
+  }
+  return iterator();
+}
+
+// class PathArgument
+// //////////////////////////////////////////////////////////////////
+
+PathArgument::PathArgument() = default;
+
+PathArgument::PathArgument(ArrayIndex index)
+    : index_(index), kind_(kindIndex) {}
+
+PathArgument::PathArgument(const char* key) : key_(key), kind_(kindKey) {}
+
+PathArgument::PathArgument(String key) : key_(std::move(key)), kind_(kindKey) {}
+
+// class Path
+// //////////////////////////////////////////////////////////////////
+
+Path::Path(const String& path, const PathArgument& a1, const PathArgument& a2,
+           const PathArgument& a3, const PathArgument& a4,
+           const PathArgument& a5) {
+  InArgs in;
+  in.reserve(5);
+  in.push_back(&a1);
+  in.push_back(&a2);
+  in.push_back(&a3);
+  in.push_back(&a4);
+  in.push_back(&a5);
+  makePath(path, in);
+}
+
+void Path::makePath(const String& path, const InArgs& in) {
+  const char* current = path.c_str();
+  const char* end = current + path.length();
+  auto itInArg = in.begin();
+  while (current != end) {
+    if (*current == '[') {
+      ++current;
+      if (*current == '%')
+        addPathInArg(path, in, itInArg, PathArgument::kindIndex);
+      else {
+        ArrayIndex index = 0;
+        for (; current != end && *current >= '0' && *current <= '9'; ++current)
+          index = index * 10 + ArrayIndex(*current - '0');
+        args_.push_back(index);
+      }
+      if (current == end || *++current != ']')
+        invalidPath(path, int(current - path.c_str()));
+    } else if (*current == '%') {
+      addPathInArg(path, in, itInArg, PathArgument::kindKey);
+      ++current;
+    } else if (*current == '.' || *current == ']') {
+      ++current;
+    } else {
+      const char* beginName = current;
+      while (current != end && !strchr("[.", *current))
+        ++current;
+      args_.push_back(String(beginName, current));
+    }
+  }
+}
+
+void Path::addPathInArg(const String& /*path*/, const InArgs& in,
+                        InArgs::const_iterator& itInArg,
+                        PathArgument::Kind kind) {
+  if (itInArg == in.end()) {
+    // Error: missing argument %d
+  } else if ((*itInArg)->kind_ != kind) {
+    // Error: bad argument type
+  } else {
+    args_.push_back(**itInArg++);
+  }
+}
+
+void Path::invalidPath(const String& /*path*/, int /*location*/) {
+  // Error: invalid path.
+}
+
+const Value& Path::resolve(const Value& root) const {
+  const Value* node = &root;
+  for (const auto& arg : args_) {
+    if (arg.kind_ == PathArgument::kindIndex) {
+      if (!node->isArray() || !node->isValidIndex(arg.index_)) {
+        // Error: unable to resolve path (array value expected at position... )
+        return Value::nullSingleton();
+      }
+      node = &((*node)[arg.index_]);
+    } else if (arg.kind_ == PathArgument::kindKey) {
+      if (!node->isObject()) {
+        // Error: unable to resolve path (object value expected at position...)
+        return Value::nullSingleton();
+      }
+      node = &((*node)[arg.key_]);
+      if (node == &Value::nullSingleton()) {
+        // Error: unable to resolve path (object has no member named '' at
+        // position...)
+        return Value::nullSingleton();
+      }
+    }
+  }
+  return *node;
+}
+
+Value Path::resolve(const Value& root, const Value& defaultValue) const {
+  const Value* node = &root;
+  for (const auto& arg : args_) {
+    if (arg.kind_ == PathArgument::kindIndex) {
+      if (!node->isArray() || !node->isValidIndex(arg.index_))
+        return defaultValue;
+      node = &((*node)[arg.index_]);
+    } else if (arg.kind_ == PathArgument::kindKey) {
+      if (!node->isObject())
+        return defaultValue;
+      node = &((*node)[arg.key_]);
+      if (node == &Value::nullSingleton())
+        return defaultValue;
+    }
+  }
+  return *node;
+}
+
+Value& Path::make(Value& root) const {
+  Value* node = &root;
+  for (const auto& arg : args_) {
+    if (arg.kind_ == PathArgument::kindIndex) {
+      if (!node->isArray()) {
+        // Error: node is not an array at position ...
+      }
+      node = &((*node)[arg.index_]);
+    } else if (arg.kind_ == PathArgument::kindKey) {
+      if (!node->isObject()) {
+        // Error: node is not an object at position...
+      }
+      node = &((*node)[arg.key_]);
+    }
+  }
+  return *node;
+}
+
+} // namespace Json
diff --git a/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_valueiterator.inl b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_valueiterator.inl
new file mode 100644
index 0000000000..d6128b8edf
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_valueiterator.inl
@@ -0,0 +1,156 @@
+// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+// included by json_value.cpp
+
+namespace Json {
+
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// class ValueIteratorBase
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+
+ValueIteratorBase::ValueIteratorBase() : current_() {}
+
+ValueIteratorBase::ValueIteratorBase(
+    const Value::ObjectValues::iterator& current)
+    : current_(current), isNull_(false) {}
+
+Value& ValueIteratorBase::deref() { return current_->second; }
+const Value& ValueIteratorBase::deref() const { return current_->second; }
+
+void ValueIteratorBase::increment() { ++current_; }
+
+void ValueIteratorBase::decrement() { --current_; }
+
+ValueIteratorBase::difference_type
+ValueIteratorBase::computeDistance(const SelfType& other) const {
+  // Iterator for null value are initialized using the default
+  // constructor, which initialize current_ to the default
+  // std::map::iterator. As begin() and end() are two instance
+  // of the default std::map::iterator, they can not be compared.
+  // To allow this, we handle this comparison specifically.
+  if (isNull_ && other.isNull_) {
+    return 0;
+  }
+
+  // Usage of std::distance is not portable (does not compile with Sun Studio 12
+  // RogueWave STL,
+  // which is the one used by default).
+  // Using a portable hand-made version for non random iterator instead:
+  //   return difference_type( std::distance( current_, other.current_ ) );
+  difference_type myDistance = 0;
+  for (Value::ObjectValues::iterator it = current_; it != other.current_;
+       ++it) {
+    ++myDistance;
+  }
+  return myDistance;
+}
+
+bool ValueIteratorBase::isEqual(const SelfType& other) const {
+  if (isNull_) {
+    return other.isNull_;
+  }
+  return current_ == other.current_;
+}
+
+void ValueIteratorBase::copy(const SelfType& other) {
+  current_ = other.current_;
+  isNull_ = other.isNull_;
+}
+
+Value ValueIteratorBase::key() const {
+  const Value::CZString czstring = (*current_).first;
+  if (czstring.data()) {
+    if (czstring.isStaticString())
+      return Value(StaticString(czstring.data()));
+    return Value(czstring.data(), czstring.data() + czstring.length());
+  }
+  return Value(czstring.index());
+}
+
+UInt ValueIteratorBase::index() const {
+  const Value::CZString czstring = (*current_).first;
+  if (!czstring.data())
+    return czstring.index();
+  return Value::UInt(-1);
+}
+
+String ValueIteratorBase::name() const {
+  char const* keey;
+  char const* end;
+  keey = memberName(&end);
+  if (!keey)
+    return String();
+  return String(keey, end);
+}
+
+char const* ValueIteratorBase::memberName() const {
+  const char* cname = (*current_).first.data();
+  return cname ? cname : "";
+}
+
+char const* ValueIteratorBase::memberName(char const** end) const {
+  const char* cname = (*current_).first.data();
+  if (!cname) {
+    *end = nullptr;
+    return nullptr;
+  }
+  *end = cname + (*current_).first.length();
+  return cname;
+}
+
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// class ValueConstIterator
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+
+ValueConstIterator::ValueConstIterator() = default;
+
+ValueConstIterator::ValueConstIterator(
+    const Value::ObjectValues::iterator& current)
+    : ValueIteratorBase(current) {}
+
+ValueConstIterator::ValueConstIterator(ValueIterator const& other)
+    : ValueIteratorBase(other) {}
+
+ValueConstIterator& ValueConstIterator::
+operator=(const ValueIteratorBase& other) {
+  copy(other);
+  return *this;
+}
+
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// class ValueIterator
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+// //////////////////////////////////////////////////////////////////
+
+ValueIterator::ValueIterator() = default;
+
+ValueIterator::ValueIterator(const Value::ObjectValues::iterator& current)
+    : ValueIteratorBase(current) {}
+
+ValueIterator::ValueIterator(const ValueConstIterator& other)
+    : ValueIteratorBase(other) {
+  throwRuntimeError("ConstIterator to Iterator should never be allowed.");
+}
+
+ValueIterator::ValueIterator(const ValueIterator& other) = default;
+
+ValueIterator& ValueIterator::operator=(const SelfType& other) {
+  copy(other);
+  return *this;
+}
+
+} // namespace Json
diff --git a/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_writer.cpp b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_writer.cpp
new file mode 100644
index 0000000000..0dd160e452
--- /dev/null
+++ b/thirdparty/openxr/src/external/jsoncpp/src/lib_json/json_writer.cpp
@@ -0,0 +1,1259 @@
+// Copyright 2011 Baptiste Lepilleur and The JsonCpp Authors
+// Distributed under MIT license, or public domain if desired and
+// recognized in your jurisdiction.
+// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
+
+#if !defined(JSON_IS_AMALGAMATION)
+#include "json_tool.h"
+#include <json/writer.h>
+#endif // if !defined(JSON_IS_AMALGAMATION)
+#include <algorithm>
+#include <cassert>
+#include <cctype>
+#include <cstring>
+#include <iomanip>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <utility>
+
+#if __cplusplus >= 201103L
+#include <cmath>
+#include <cstdio>
+
+#if !defined(isnan)
+#define isnan std::isnan
+#endif
+
+#if !defined(isfinite)
+#define isfinite std::isfinite
+#endif
+
+#else
+#include <cmath>
+#include <cstdio>
+
+#if defined(_MSC_VER)
+#if !defined(isnan)
+#include <float.h>
+#define isnan _isnan
+#endif
+
+#if !defined(isfinite)
+#include <float.h>
+#define isfinite _finite
+#endif
+
+#if !defined(_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES)
+#define _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES 1
+#endif //_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES
+
+#endif //_MSC_VER
+
+#if defined(__sun) && defined(__SVR4) // Solaris
+#if !defined(isfinite)
+#include <ieeefp.h>
+#define isfinite finite
+#endif
+#endif
+
+#if defined(__hpux)
+#if !defined(isfinite)
+#if defined(__ia64) && !defined(finite)
+#define isfinite(x)                                                            \
+  ((sizeof(x) == sizeof(float) ? _Isfinitef(x) : _IsFinite(x)))
+#endif
+#endif
+#endif
+
+#if !defined(isnan)
+// IEEE standard states that NaN values will not compare to themselves
+#define isnan(x) ((x) != (x))
+#endif
+
+#if !defined(__APPLE__)
+#if !defined(isfinite)
+#define isfinite finite
+#endif
+#endif
+#endif
+
+#if defined(_MSC_VER)
+// Disable warning about strdup being deprecated.
+#pragma warning(disable : 4996)
+#endif
+
+namespace Json {
+
+#if __cplusplus >= 201103L || (defined(_CPPLIB_VER) && _CPPLIB_VER >= 520)
+using StreamWriterPtr = std::unique_ptr<StreamWriter>;
+#else
+using StreamWriterPtr = std::auto_ptr<StreamWriter>;
+#endif
+
+String valueToString(LargestInt value) {
+  UIntToStringBuffer buffer;
+  char* current = buffer + sizeof(buffer);
+  if (value == Value::minLargestInt) {
+    uintToString(LargestUInt(Value::maxLargestInt) + 1, current);
+    *--current = '-';
+  } else if (value < 0) {
+    uintToString(LargestUInt(-value), current);
+    *--current = '-';
+  } else {
+    uintToString(LargestUInt(value), current);
+  }
+  assert(current >= buffer);
+  return current;
+}
+
+String valueToString(LargestUInt value) {
+  UIntToStringBuffer buffer;
+  char* current = buffer + sizeof(buffer);
+  uintToString(value, current);
+  assert(current >= buffer);
+  return current;
+}
+
+#if defined(JSON_HAS_INT64)
+
+String valueToString(Int value) { return valueToString(LargestInt(value)); }
+
+String valueToString(UInt value) { return valueToString(LargestUInt(value)); }
+
+#endif // # if defined(JSON_HAS_INT64)
+
+namespace {
+String valueToString(double value, bool useSpecialFloats,
+                     unsigned int precision, PrecisionType precisionType) {
+  // Print into the buffer. We need not request the alternative representation
+  // that always has a decimal point because JSON doesn't distinguish the
+  // concepts of reals and integers.
+  if (!isfinite(value)) {
+    static const char* const reps[2][3] = {{"NaN", "-Infinity", "Infinity"},
+                                           {"null", "-1e+9999", "1e+9999"}};
+    return reps[useSpecialFloats ? 0 : 1]
+               [isnan(value) ? 0 : (value < 0) ? 1 : 2];
+  }
+
+  String buffer(size_t(36), '\0');
+  while (true) {
+    int len = jsoncpp_snprintf(
+        &*buffer.begin(), buffer.size(),
+        (precisionType == PrecisionType::significantDigits) ? "%.*g" : "%.*f",
+        precision, value);
+    assert(len >= 0);
+    auto wouldPrint = static_cast<size_t>(len);
+    if (wouldPrint >= buffer.size()) {
+      buffer.resize(wouldPrint + 1);
+      continue;
+    }
+    buffer.resize(wouldPrint);
+    break;
+  }
+
+  buffer.erase(fixNumericLocale(buffer.begin(), buffer.end()), buffer.end());
+
+  // try to ensure we preserve the fact that this was given to us as a double on
+  // input
+  if (buffer.find('.') == buffer.npos && buffer.find('e') == buffer.npos) {
+    buffer += ".0";
+  }
+
+  // strip the zero padding from the right
+  if (precisionType == PrecisionType::decimalPlaces) {
+    buffer.erase(fixZerosInTheEnd(buffer.begin(), buffer.end(), precision),
+                 buffer.end());
+  }
+
+  return buffer;
+}
+} // namespace
+
+String valueToString(double value, unsigned int precision,
+                     PrecisionType precisionType) {
+  return valueToString(value, false, precision, precisionType);
+}
+
+String valueToString(bool value) { return value ? "true" : "false"; }
+
+static bool doesAnyCharRequireEscaping(char const* s, size_t n) {
+  assert(s || !n);
+
+  return std::any_of(s, s + n, [](unsigned char c) {
+    return c == '\\' || c == '"' || c < 0x20 || c > 0x7F;
+  });
+}
+
+static unsigned int utf8ToCodepoint(const char*& s, const char* e) {
+  const unsigned int REPLACEMENT_CHARACTER = 0xFFFD;
+
+  unsigned int firstByte = static_cast<unsigned char>(*s);
+
+  if (firstByte < 0x80)
+    return firstByte;
+
+  if (firstByte < 0xE0) {
+    if (e - s < 2)
+      return REPLACEMENT_CHARACTER;
+
+    unsigned int calculated =
+        ((firstByte & 0x1F) << 6) | (static_cast<unsigned int>(s[1]) & 0x3F);
+    s += 1;
+    // oversized encoded characters are invalid
+    return calculated < 0x80 ? REPLACEMENT_CHARACTER : calculated;
+  }
+
+  if (firstByte < 0xF0) {
+    if (e - s < 3)
+      return REPLACEMENT_CHARACTER;
+
+    unsigned int calculated = ((firstByte & 0x0F) << 12) |
+                              ((static_cast<unsigned int>(s[1]) & 0x3F) << 6) |
+                              (static_cast<unsigned int>(s[2]) & 0x3F);
+    s += 2;
+    // surrogates aren't valid codepoints itself
+    // shouldn't be UTF-8 encoded
+    if (calculated >= 0xD800 && calculated <= 0xDFFF)
+      return REPLACEMENT_CHARACTER;
+    // oversized encoded characters are invalid
+    return calculated < 0x800 ? REPLACEMENT_CHARACTER : calculated;
+  }
+
+  if (firstByte < 0xF8) {
+    if (e - s < 4)
+      return REPLACEMENT_CHARACTER;
+
+    unsigned int calculated = ((firstByte & 0x07) << 18) |
+                              ((static_cast<unsigned int>(s[1]) & 0x3F) << 12) |
+                              ((static_cast<unsigned int>(s[2]) & 0x3F) << 6) |
+                              (static_cast<unsigned int>(s[3]) & 0x3F);
+    s += 3;
+    // oversized encoded characters are invalid
+    return calculated < 0x10000 ? REPLACEMENT_CHARACTER : calculated;
+  }
+
+  return REPLACEMENT_CHARACTER;
+}
+
+static const char hex2[] = "000102030405060708090a0b0c0d0e0f"
+                           "101112131415161718191a1b1c1d1e1f"
+                           "202122232425262728292a2b2c2d2e2f"
+                           "303132333435363738393a3b3c3d3e3f"
+                           "404142434445464748494a4b4c4d4e4f"
+                           "505152535455565758595a5b5c5d5e5f"
+                           "606162636465666768696a6b6c6d6e6f"
+                           "707172737475767778797a7b7c7d7e7f"
+                           "808182838485868788898a8b8c8d8e8f"
+                           "909192939495969798999a9b9c9d9e9f"
+                           "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf"
+                           "b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
+                           "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
+                           "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
+                           "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
+                           "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff";
+
+static String toHex16Bit(unsigned int x) {
+  const unsigned int hi = (x >> 8) & 0xff;
+  const unsigned int lo = x & 0xff;
+  String result(4, ' ');
+  result[0] = hex2[2 * hi];
+  result[1] = hex2[2 * hi + 1];
+  result[2] = hex2[2 * lo];
+  result[3] = hex2[2 * lo + 1];
+  return result;
+}
+
+static void appendRaw(String& result, unsigned ch) {
+  result += static_cast<char>(ch);
+}
+
+static void appendHex(String& result, unsigned ch) {
+  result.append("\\u").append(toHex16Bit(ch));
+}
+
+static String valueToQuotedStringN(const char* value, size_t length,
+                                   bool emitUTF8 = false) {
+  if (value == nullptr)
+    return "";
+
+  if (!doesAnyCharRequireEscaping(value, length))
+    return String("\"") + value + "\"";
+  // We have to walk value and escape any special characters.
+  // Appending to String is not efficient, but this should be rare.
+  // (Note: forward slashes are *not* rare, but I am not escaping them.)
+  String::size_type maxsize = length * 2 + 3; // allescaped+quotes+NULL
+  String result;
+  result.reserve(maxsize); // to avoid lots of mallocs
+  result += "\"";
+  char const* end = value + length;
+  for (const char* c = value; c != end; ++c) {
+    switch (*c) {
+    case '\"':
+      result += "\\\"";
+      break;
+    case '\\':
+      result += "\\\\";
+      break;
+    case '\b':
+      result += "\\b";
+      break;
+    case '\f':
+      result += "\\f";
+      break;
+    case '\n':
+      result += "\\n";
+      break;
+    case '\r':
+      result += "\\r";
+      break;
+    case '\t':
+      result += "\\t";
+      break;
+    // case '/':
+    // Even though \/ is considered a legal escape in JSON, a bare
+    // slash is also legal, so I see no reason to escape it.
+    // (I hope I am not misunderstanding something.)
+    // blep notes: actually escaping \/ may be useful in javascript to avoid </
+    // sequence.
+    // Should add a flag to allow this compatibility mode and prevent this
+    // sequence from occurring.
+    default: {
+      if (emitUTF8) {
+        unsigned codepoint = static_cast<unsigned char>(*c);
+        if (codepoint < 0x20) {
+          appendHex(result, codepoint);
+        } else {
+          appendRaw(result, codepoint);
+        }
+      } else {
+        unsigned codepoint = utf8ToCodepoint(c, end); // modifies `c`
+        if (codepoint < 0x20) {
+          appendHex(result, codepoint);
+        } else if (codepoint < 0x80) {
+          appendRaw(result, codepoint);
+        } else if (codepoint < 0x10000) {
+          // Basic Multilingual Plane
+          appendHex(result, codepoint);
+        } else {
+          // Extended Unicode. Encode 20 bits as a surrogate pair.
+          codepoint -= 0x10000;
+          appendHex(result, 0xd800 + ((codepoint >> 10) & 0x3ff));
+          appendHex(result, 0xdc00 + (codepoint & 0x3ff));
+        }
+      }
+    } break;
+    }
+  }
+  result += "\"";
+  return result;
+}
+
+String valueToQuotedString(const char* value) {
+  return valueToQuotedStringN(value, strlen(value));
+}
+
+// Class Writer
+// //////////////////////////////////////////////////////////////////
+Writer::~Writer() = default;
+
+// Class FastWriter
+// //////////////////////////////////////////////////////////////////
+
+FastWriter::FastWriter()
+
+    = default;
+
+void FastWriter::enableYAMLCompatibility() { yamlCompatibilityEnabled_ = true; }
+
+void FastWriter::dropNullPlaceholders() { dropNullPlaceholders_ = true; }
+
+void FastWriter::omitEndingLineFeed() { omitEndingLineFeed_ = true; }
+
+String FastWriter::write(const Value& root) {
+  document_.clear();
+  writeValue(root);
+  if (!omitEndingLineFeed_)
+    document_ += '\n';
+  return document_;
+}
+
+void FastWriter::writeValue(const Value& value) {
+  switch (value.type()) {
+  case nullValue:
+    if (!dropNullPlaceholders_)
+      document_ += "null";
+    break;
+  case intValue:
+    document_ += valueToString(value.asLargestInt());
+    break;
+  case uintValue:
+    document_ += valueToString(value.asLargestUInt());
+    break;
+  case realValue:
+    document_ += valueToString(value.asDouble());
+    break;
+  case stringValue: {
+    // Is NULL possible for value.string_? No.
+    char const* str;
+    char const* end;
+    bool ok = value.getString(&str, &end);
+    if (ok)
+      document_ += valueToQuotedStringN(str, static_cast<size_t>(end - str));
+    break;
+  }
+  case booleanValue:
+    document_ += valueToString(value.asBool());
+    break;
+  case arrayValue: {
+    document_ += '[';
+    ArrayIndex size = value.size();
+    for (ArrayIndex index = 0; index < size; ++index) {
+      if (index > 0)
+        document_ += ',';
+      writeValue(value[index]);
+    }
+    document_ += ']';
+  } break;
+  case objectValue: {
+    Value::Members members(value.getMemberNames());
+    document_ += '{';
+    for (auto it = members.begin(); it != members.end(); ++it) {
+      const String& name = *it;
+      if (it != members.begin())
+        document_ += ',';
+      document_ += valueToQuotedStringN(name.data(), name.length());
+      document_ += yamlCompatibilityEnabled_ ? ": " : ":";
+      writeValue(value[name]);
+    }
+    document_ += '}';
+  } break;
+  }
+}
+
+// Class StyledWriter
+// //////////////////////////////////////////////////////////////////
+
+StyledWriter::StyledWriter() = default;
+
+String StyledWriter::write(const Value& root) {
+  document_.clear();
+  addChildValues_ = false;
+  indentString_.clear();
+  writeCommentBeforeValue(root);
+  writeValue(root);
+  writeCommentAfterValueOnSameLine(root);
+  document_ += '\n';
+  return document_;
+}
+
+void StyledWriter::writeValue(const Value& value) {
+  switch (value.type()) {
+  case nullValue:
+    pushValue("null");
+    break;
+  case intValue:
+    pushValue(valueToString(value.asLargestInt()));
+    break;
+  case uintValue:
+    pushValue(valueToString(value.asLargestUInt()));
+    break;
+  case realValue:
+    pushValue(valueToString(value.asDouble()));
+    break;
+  case stringValue: {
+    // Is NULL possible for value.string_? No.
+    char const* str;
+    char const* end;
+    bool ok = value.getString(&str, &end);
+    if (ok)
+      pushValue(valueToQuotedStringN(str, static_cast<size_t>(end - str)));
+    else
+      pushValue("");
+    break;
+  }
+  case booleanValue:
+    pushValue(valueToString(value.asBool()));
+    break;
+  case arrayValue:
+    writeArrayValue(value);
+    break;
+  case objectValue: {
+    Value::Members members(value.getMemberNames());
+    if (members.empty())
+      pushValue("{}");
+    else {
+      writeWithIndent("{");
+      indent();
+      auto it = members.begin();
+      for (;;) {
+        const String& name = *it;
+        const Value& childValue = value[name];
+        writeCommentBeforeValue(childValue);
+        writeWithIndent(valueToQuotedString(name.c_str()));
+        document_ += " : ";
+        writeValue(childValue);
+        if (++it == members.end()) {
+          writeCommentAfterValueOnSameLine(childValue);
+          break;
+        }
+        document_ += ',';
+        writeCommentAfterValueOnSameLine(childValue);
+      }
+      unindent();
+      writeWithIndent("}");
+    }
+  } break;
+  }
+}
+
+void StyledWriter::writeArrayValue(const Value& value) {
+  size_t size = value.size();
+  if (size == 0)
+    pushValue("[]");
+  else {
+    bool isArrayMultiLine = isMultilineArray(value);
+    if (isArrayMultiLine) {
+      writeWithIndent("[");
+      indent();
+      bool hasChildValue = !childValues_.empty();
+      ArrayIndex index = 0;
+      for (;;) {
+        const Value& childValue = value[index];
+        writeCommentBeforeValue(childValue);
+        if (hasChildValue)
+          writeWithIndent(childValues_[index]);
+        else {
+          writeIndent();
+          writeValue(childValue);
+        }
+        if (++index == size) {
+          writeCommentAfterValueOnSameLine(childValue);
+          break;
+        }
+        document_ += ',';
+        writeCommentAfterValueOnSameLine(childValue);
+      }
+      unindent();
+      writeWithIndent("]");
+    } else // output on a single line
+    {
+      assert(childValues_.size() == size);
+      document_ += "[ ";
+      for (size_t index = 0; index < size; ++index) {
+        if (index > 0)
+          document_ += ", ";
+        document_ += childValues_[index];
+      }
+      document_ += " ]";
+    }
+  }
+}
+
+bool StyledWriter::isMultilineArray(const Value& value) {
+  ArrayIndex const size = value.size();
+  bool isMultiLine = size * 3 >= rightMargin_;
+  childValues_.clear();
+  for (ArrayIndex index = 0; index < size && !isMultiLine; ++index) {
+    const Value& childValue = value[index];
+    isMultiLine = ((childValue.isArray() || childValue.isObject()) &&
+                   !childValue.empty());
+  }
+  if (!isMultiLine) // check if line length > max line length
+  {
+    childValues_.reserve(size);
+    addChildValues_ = true;
+    ArrayIndex lineLength = 4 + (size - 1) * 2; // '[ ' + ', '*n + ' ]'
+    for (ArrayIndex index = 0; index < size; ++index) {
+      if (hasCommentForValue(value[index])) {
+        isMultiLine = true;
+      }
+      writeValue(value[index]);
+      lineLength += static_cast<ArrayIndex>(childValues_[index].length());
+    }
+    addChildValues_ = false;
+    isMultiLine = isMultiLine || lineLength >= rightMargin_;
+  }
+  return isMultiLine;
+}
+
+void StyledWriter::pushValue(const String& value) {
+  if (addChildValues_)
+    childValues_.push_back(value);
+  else
+    document_ += value;
+}
+
+void StyledWriter::writeIndent() {
+  if (!document_.empty()) {
+    char last = document_[document_.length() - 1];
+    if (last == ' ') // already indented
+      return;
+    if (last != '\n') // Comments may add new-line
+      document_ += '\n';
+  }
+  document_ += indentString_;
+}
+
+void StyledWriter::writeWithIndent(const String& value) {
+  writeIndent();
+  document_ += value;
+}
+
+void StyledWriter::indent() { indentString_ += String(indentSize_, ' '); }
+
+void StyledWriter::unindent() {
+  assert(indentString_.size() >= indentSize_);
+  indentString_.resize(indentString_.size() - indentSize_);
+}
+
+void StyledWriter::writeCommentBeforeValue(const Value& root) {
+  if (!root.hasComment(commentBefore))
+    return;
+
+  document_ += '\n';
+  writeIndent();
+  const String& comment = root.getComment(commentBefore);
+  String::const_iterator iter = comment.begin();
+  while (iter != comment.end()) {
+    document_ += *iter;
+    if (*iter == '\n' && ((iter + 1) != comment.end() && *(iter + 1) == '/'))
+      writeIndent();
+    ++iter;
+  }
+
+  // Comments are stripped of trailing newlines, so add one here
+  document_ += '\n';
+}
+
+void StyledWriter::writeCommentAfterValueOnSameLine(const Value& root) {
+  if (root.hasComment(commentAfterOnSameLine))
+    document_ += " " + root.getComment(commentAfterOnSameLine);
+
+  if (root.hasComment(commentAfter)) {
+    document_ += '\n';
+    document_ += root.getComment(commentAfter);
+    document_ += '\n';
+  }
+}
+
+bool StyledWriter::hasCommentForValue(const Value& value) {
+  return value.hasComment(commentBefore) ||
+         value.hasComment(commentAfterOnSameLine) ||
+         value.hasComment(commentAfter);
+}
+
+// Class StyledStreamWriter
+// //////////////////////////////////////////////////////////////////
+
+StyledStreamWriter::StyledStreamWriter(String indentation)
+    : document_(nullptr), indentation_(std::move(indentation)),
+      addChildValues_(), indented_(false) {}
+
+void StyledStreamWriter::write(OStream& out, const Value& root) {
+  document_ = &out;
+  addChildValues_ = false;
+  indentString_.clear();
+  indented_ = true;
+  writeCommentBeforeValue(root);
+  if (!indented_)
+    writeIndent();
+  indented_ = true;
+  writeValue(root);
+  writeCommentAfterValueOnSameLine(root);
+  *document_ << "\n";
+  document_ = nullptr; // Forget the stream, for safety.
+}
+
+void StyledStreamWriter::writeValue(const Value& value) {
+  switch (value.type()) {
+  case nullValue:
+    pushValue("null");
+    break;
+  case intValue:
+    pushValue(valueToString(value.asLargestInt()));
+    break;
+  case uintValue:
+    pushValue(valueToString(value.asLargestUInt()));
+    break;
+  case realValue:
+    pushValue(valueToString(value.asDouble()));
+    break;
+  case stringValue: {
+    // Is NULL possible for value.string_? No.
+    char const* str;
+    char const* end;
+    bool ok = value.getString(&str, &end);
+    if (ok)
+      pushValue(valueToQuotedStringN(str, static_cast<size_t>(end - str)));
+    else
+      pushValue("");
+    break;
+  }
+  case booleanValue:
+    pushValue(valueToString(value.asBool()));
+    break;
+  case arrayValue:
+    writeArrayValue(value);
+    break;
+  case objectValue: {
+    Value::Members members(value.getMemberNames());
+    if (members.empty())
+      pushValue("{}");
+    else {
+      writeWithIndent("{");
+      indent();
+      auto it = members.begin();
+      for (;;) {
+        const String& name = *it;
+        const Value& childValue = value[name];
+        writeCommentBeforeValue(childValue);
+        writeWithIndent(valueToQuotedString(name.c_str()));
+        *document_ << " : ";
+        writeValue(childValue);
+        if (++it == members.end()) {
+          writeCommentAfterValueOnSameLine(childValue);
+          break;
+        }
+        *document_ << ",";
+        writeCommentAfterValueOnSameLine(childValue);
+      }
+      unindent();
+      writeWithIndent("}");
+    }
+  } break;
+  }
+}
+
+void StyledStreamWriter::writeArrayValue(const Value& value) {
+  unsigned size = value.size();
+  if (size == 0)
+    pushValue("[]");
+  else {
+    bool isArrayMultiLine = isMultilineArray(value);
+    if (isArrayMultiLine) {
+      writeWithIndent("[");
+      indent();
+      bool hasChildValue = !childValues_.empty();
+      unsigned index = 0;
+      for (;;) {
+        const Value& childValue = value[index];
+        writeCommentBeforeValue(childValue);
+        if (hasChildValue)
+          writeWithIndent(childValues_[index]);
+        else {
+          if (!indented_)
+            writeIndent();
+          indented_ = true;
+          writeValue(childValue);
+          indented_ = false;
+        }
+        if (++index == size) {
+          writeCommentAfterValueOnSameLine(childValue);
+          break;
+        }
+        *document_ << ",";
+        writeCommentAfterValueOnSameLine(childValue);
+      }
+      unindent();
+      writeWithIndent("]");
+    } else // output on a single line
+    {
+      assert(childValues_.size() == size);
+      *document_ << "[ ";
+      for (unsigned index = 0; index < size; ++index) {
+        if (index > 0)
+          *document_ << ", ";
+        *document_ << childValues_[index];
+      }
+      *document_ << " ]";
+    }
+  }
+}
+
+bool StyledStreamWriter::isMultilineArray(const Value& value) {
+  ArrayIndex const size = value.size();
+  bool isMultiLine = size * 3 >= rightMargin_;
+  childValues_.clear();
+  for (ArrayIndex index = 0; index < size && !isMultiLine; ++index) {
+    const Value& childValue = value[index];
+    isMultiLine = ((childValue.isArray() || childValue.isObject()) &&
+                   !childValue.empty());
+  }
+  if (!isMultiLine) // check if line length > max line length
+  {
+    childValues_.reserve(size);
+    addChildValues_ = true;
+    ArrayIndex lineLength = 4 + (size - 1) * 2; // '[ ' + ', '*n + ' ]'
+    for (ArrayIndex index = 0; index < size; ++index) {
+      if (hasCommentForValue(value[index])) {
+        isMultiLine = true;
+      }
+      writeValue(value[index]);
+      lineLength += static_cast<ArrayIndex>(childValues_[index].length());
+    }
+    addChildValues_ = false;
+    isMultiLine = isMultiLine || lineLength >= rightMargin_;
+  }
+  return isMultiLine;
+}
+
+void StyledStreamWriter::pushValue(const String& value) {
+  if (addChildValues_)
+    childValues_.push_back(value);
+  else
+    *document_ << value;
+}
+
+void StyledStreamWriter::writeIndent() {
+  // blep intended this to look at the so-far-written string
+  // to determine whether we are already indented, but
+  // with a stream we cannot do that. So we rely on some saved state.
+  // The caller checks indented_.
+  *document_ << '\n' << indentString_;
+}
+
+void StyledStreamWriter::writeWithIndent(const String& value) {
+  if (!indented_)
+    writeIndent();
+  *document_ << value;
+  indented_ = false;
+}
+
+void StyledStreamWriter::indent() { indentString_ += indentation_; }
+
+void StyledStreamWriter::unindent() {
+  assert(indentString_.size() >= indentation_.size());
+  indentString_.resize(indentString_.size() - indentation_.size());
+}
+
+void StyledStreamWriter::writeCommentBeforeValue(const Value& root) {
+  if (!root.hasComment(commentBefore))
+    return;
+
+  if (!indented_)
+    writeIndent();
+  const String& comment = root.getComment(commentBefore);
+  String::const_iterator iter = comment.begin();
+  while (iter != comment.end()) {
+    *document_ << *iter;
+    if (*iter == '\n' && ((iter + 1) != comment.end() && *(iter + 1) == '/'))
+      // writeIndent();  // would include newline
+      *document_ << indentString_;
+    ++iter;
+  }
+  indented_ = false;
+}
+
+void StyledStreamWriter::writeCommentAfterValueOnSameLine(const Value& root) {
+  if (root.hasComment(commentAfterOnSameLine))
+    *document_ << ' ' << root.getComment(commentAfterOnSameLine);
+
+  if (root.hasComment(commentAfter)) {
+    writeIndent();
+    *document_ << root.getComment(commentAfter);
+  }
+  indented_ = false;
+}
+
+bool StyledStreamWriter::hasCommentForValue(const Value& value) {
+  return value.hasComment(commentBefore) ||
+         value.hasComment(commentAfterOnSameLine) ||
+         value.hasComment(commentAfter);
+}
+
+//////////////////////////
+// BuiltStyledStreamWriter
+
+/// Scoped enums are not available until C++11.
+struct CommentStyle {
+  /// Decide whether to write comments.
+  enum Enum {
+    None, ///< Drop all comments.
+    Most, ///< Recover odd behavior of previous versions (not implemented yet).
+    All   ///< Keep all comments.
+  };
+};
+
+struct BuiltStyledStreamWriter : public StreamWriter {
+  BuiltStyledStreamWriter(String indentation, CommentStyle::Enum cs,
+                          String colonSymbol, String nullSymbol,
+                          String endingLineFeedSymbol, bool useSpecialFloats,
+                          bool emitUTF8, unsigned int precision,
+                          PrecisionType precisionType);
+  int write(Value const& root, OStream* sout) override;
+
+private:
+  void writeValue(Value const& value);
+  void writeArrayValue(Value const& value);
+  bool isMultilineArray(Value const& value);
+  void pushValue(String const& value);
+  void writeIndent();
+  void writeWithIndent(String const& value);
+  void indent();
+  void unindent();
+  void writeCommentBeforeValue(Value const& root);
+  void writeCommentAfterValueOnSameLine(Value const& root);
+  static bool hasCommentForValue(const Value& value);
+
+  using ChildValues = std::vector<String>;
+
+  ChildValues childValues_;
+  String indentString_;
+  unsigned int rightMargin_;
+  String indentation_;
+  CommentStyle::Enum cs_;
+  String colonSymbol_;
+  String nullSymbol_;
+  String endingLineFeedSymbol_;
+  bool addChildValues_ : 1;
+  bool indented_ : 1;
+  bool useSpecialFloats_ : 1;
+  bool emitUTF8_ : 1;
+  unsigned int precision_;
+  PrecisionType precisionType_;
+};
+BuiltStyledStreamWriter::BuiltStyledStreamWriter(
+    String indentation, CommentStyle::Enum cs, String colonSymbol,
+    String nullSymbol, String endingLineFeedSymbol, bool useSpecialFloats,
+    bool emitUTF8, unsigned int precision, PrecisionType precisionType)
+    : rightMargin_(74), indentation_(std::move(indentation)), cs_(cs),
+      colonSymbol_(std::move(colonSymbol)), nullSymbol_(std::move(nullSymbol)),
+      endingLineFeedSymbol_(std::move(endingLineFeedSymbol)),
+      addChildValues_(false), indented_(false),
+      useSpecialFloats_(useSpecialFloats), emitUTF8_(emitUTF8),
+      precision_(precision), precisionType_(precisionType) {}
+int BuiltStyledStreamWriter::write(Value const& root, OStream* sout) {
+  sout_ = sout;
+  addChildValues_ = false;
+  indented_ = true;
+  indentString_.clear();
+  writeCommentBeforeValue(root);
+  if (!indented_)
+    writeIndent();
+  indented_ = true;
+  writeValue(root);
+  writeCommentAfterValueOnSameLine(root);
+  *sout_ << endingLineFeedSymbol_;
+  sout_ = nullptr;
+  return 0;
+}
+void BuiltStyledStreamWriter::writeValue(Value const& value) {
+  switch (value.type()) {
+  case nullValue:
+    pushValue(nullSymbol_);
+    break;
+  case intValue:
+    pushValue(valueToString(value.asLargestInt()));
+    break;
+  case uintValue:
+    pushValue(valueToString(value.asLargestUInt()));
+    break;
+  case realValue:
+    pushValue(valueToString(value.asDouble(), useSpecialFloats_, precision_,
+                            precisionType_));
+    break;
+  case stringValue: {
+    // Is NULL is possible for value.string_? No.
+    char const* str;
+    char const* end;
+    bool ok = value.getString(&str, &end);
+    if (ok)
+      pushValue(
+          valueToQuotedStringN(str, static_cast<size_t>(end - str), emitUTF8_));
+    else
+      pushValue("");
+    break;
+  }
+  case booleanValue:
+    pushValue(valueToString(value.asBool()));
+    break;
+  case arrayValue:
+    writeArrayValue(value);
+    break;
+  case objectValue: {
+    Value::Members members(value.getMemberNames());
+    if (members.empty())
+      pushValue("{}");
+    else {
+      writeWithIndent("{");
+      indent();
+      auto it = members.begin();
+      for (;;) {
+        String const& name = *it;
+        Value const& childValue = value[name];
+        writeCommentBeforeValue(childValue);
+        writeWithIndent(
+            valueToQuotedStringN(name.data(), name.length(), emitUTF8_));
+        *sout_ << colonSymbol_;
+        writeValue(childValue);
+        if (++it == members.end()) {
+          writeCommentAfterValueOnSameLine(childValue);
+          break;
+        }
+        *sout_ << ",";
+        writeCommentAfterValueOnSameLine(childValue);
+      }
+      unindent();
+      writeWithIndent("}");
+    }
+  } break;
+  }
+}
+
+void BuiltStyledStreamWriter::writeArrayValue(Value const& value) {
+  unsigned size = value.size();
+  if (size == 0)
+    pushValue("[]");
+  else {
+    bool isMultiLine = (cs_ == CommentStyle::All) || isMultilineArray(value);
+    if (isMultiLine) {
+      writeWithIndent("[");
+      indent();
+      bool hasChildValue = !childValues_.empty();
+      unsigned index = 0;
+      for (;;) {
+        Value const& childValue = value[index];
+        writeCommentBeforeValue(childValue);
+        if (hasChildValue)
+          writeWithIndent(childValues_[index]);
+        else {
+          if (!indented_)
+            writeIndent();
+          indented_ = true;
+          writeValue(childValue);
+          indented_ = false;
+        }
+        if (++index == size) {
+          writeCommentAfterValueOnSameLine(childValue);
+          break;
+        }
+        *sout_ << ",";
+        writeCommentAfterValueOnSameLine(childValue);
+      }
+      unindent();
+      writeWithIndent("]");
+    } else // output on a single line
+    {
+      assert(childValues_.size() == size);
+      *sout_ << "[";
+      if (!indentation_.empty())
+        *sout_ << " ";
+      for (unsigned index = 0; index < size; ++index) {
+        if (index > 0)
+          *sout_ << ((!indentation_.empty()) ? ", " : ",");
+        *sout_ << childValues_[index];
+      }
+      if (!indentation_.empty())
+        *sout_ << " ";
+      *sout_ << "]";
+    }
+  }
+}
+
+bool BuiltStyledStreamWriter::isMultilineArray(Value const& value) {
+  ArrayIndex const size = value.size();
+  bool isMultiLine = size * 3 >= rightMargin_;
+  childValues_.clear();
+  for (ArrayIndex index = 0; index < size && !isMultiLine; ++index) {
+    Value const& childValue = value[index];
+    isMultiLine = ((childValue.isArray() || childValue.isObject()) &&
+                   !childValue.empty());
+  }
+  if (!isMultiLine) // check if line length > max line length
+  {
+    childValues_.reserve(size);
+    addChildValues_ = true;
+    ArrayIndex lineLength = 4 + (size - 1) * 2; // '[ ' + ', '*n + ' ]'
+    for (ArrayIndex index = 0; index < size; ++index) {
+      if (hasCommentForValue(value[index])) {
+        isMultiLine = true;
+      }
+      writeValue(value[index]);
+      lineLength += static_cast<ArrayIndex>(childValues_[index].length());
+    }
+    addChildValues_ = false;
+    isMultiLine = isMultiLine || lineLength >= rightMargin_;
+  }
+  return isMultiLine;
+}
+
+void BuiltStyledStreamWriter::pushValue(String const& value) {
+  if (addChildValues_)
+    childValues_.push_back(value);
+  else
+    *sout_ << value;
+}
+
+void BuiltStyledStreamWriter::writeIndent() {
+  // blep intended this to look at the so-far-written string
+  // to determine whether we are already indented, but
+  // with a stream we cannot do that. So we rely on some saved state.
+  // The caller checks indented_.
+
+  if (!indentation_.empty()) {
+    // In this case, drop newlines too.
+    *sout_ << '\n' << indentString_;
+  }
+}
+
+void BuiltStyledStreamWriter::writeWithIndent(String const& value) {
+  if (!indented_)
+    writeIndent();
+  *sout_ << value;
+  indented_ = false;
+}
+
+void BuiltStyledStreamWriter::indent() { indentString_ += indentation_; }
+
+void BuiltStyledStreamWriter::unindent() {
+  assert(indentString_.size() >= indentation_.size());
+  indentString_.resize(indentString_.size() - indentation_.size());
+}
+
+void BuiltStyledStreamWriter::writeCommentBeforeValue(Value const& root) {
+  if (cs_ == CommentStyle::None)
+    return;
+  if (!root.hasComment(commentBefore))
+    return;
+
+  if (!indented_)
+    writeIndent();
+  const String& comment = root.getComment(commentBefore);
+  String::const_iterator iter = comment.begin();
+  while (iter != comment.end()) {
+    *sout_ << *iter;
+    if (*iter == '\n' && ((iter + 1) != comment.end() && *(iter + 1) == '/'))
+      // writeIndent();  // would write extra newline
+      *sout_ << indentString_;
+    ++iter;
+  }
+  indented_ = false;
+}
+
+void BuiltStyledStreamWriter::writeCommentAfterValueOnSameLine(
+    Value const& root) {
+  if (cs_ == CommentStyle::None)
+    return;
+  if (root.hasComment(commentAfterOnSameLine))
+    *sout_ << " " + root.getComment(commentAfterOnSameLine);
+
+  if (root.hasComment(commentAfter)) {
+    writeIndent();
+    *sout_ << root.getComment(commentAfter);
+  }
+}
+
+// static
+bool BuiltStyledStreamWriter::hasCommentForValue(const Value& value) {
+  return value.hasComment(commentBefore) ||
+         value.hasComment(commentAfterOnSameLine) ||
+         value.hasComment(commentAfter);
+}
+
+///////////////
+// StreamWriter
+
+StreamWriter::StreamWriter() : sout_(nullptr) {}
+StreamWriter::~StreamWriter() = default;
+StreamWriter::Factory::~Factory() = default;
+StreamWriterBuilder::StreamWriterBuilder() { setDefaults(&settings_); }
+StreamWriterBuilder::~StreamWriterBuilder() = default;
+StreamWriter* StreamWriterBuilder::newStreamWriter() const {
+  const String indentation = settings_["indentation"].asString();
+  const String cs_str = settings_["commentStyle"].asString();
+  const String pt_str = settings_["precisionType"].asString();
+  const bool eyc = settings_["enableYAMLCompatibility"].asBool();
+  const bool dnp = settings_["dropNullPlaceholders"].asBool();
+  const bool usf = settings_["useSpecialFloats"].asBool();
+  const bool emitUTF8 = settings_["emitUTF8"].asBool();
+  unsigned int pre = settings_["precision"].asUInt();
+  CommentStyle::Enum cs = CommentStyle::All;
+  if (cs_str == "All") {
+    cs = CommentStyle::All;
+  } else if (cs_str == "None") {
+    cs = CommentStyle::None;
+  } else {
+    throwRuntimeError("commentStyle must be 'All' or 'None'");
+  }
+  PrecisionType precisionType(significantDigits);
+  if (pt_str == "significant") {
+    precisionType = PrecisionType::significantDigits;
+  } else if (pt_str == "decimal") {
+    precisionType = PrecisionType::decimalPlaces;
+  } else {
+    throwRuntimeError("precisionType must be 'significant' or 'decimal'");
+  }
+  String colonSymbol = " : ";
+  if (eyc) {
+    colonSymbol = ": ";
+  } else if (indentation.empty()) {
+    colonSymbol = ":";
+  }
+  String nullSymbol = "null";
+  if (dnp) {
+    nullSymbol.clear();
+  }
+  if (pre > 17)
+    pre = 17;
+  String endingLineFeedSymbol;
+  return new BuiltStyledStreamWriter(indentation, cs, colonSymbol, nullSymbol,
+                                     endingLineFeedSymbol, usf, emitUTF8, pre,
+                                     precisionType);
+}
+
+bool StreamWriterBuilder::validate(Json::Value* invalid) const {
+  static const auto& valid_keys = *new std::set<String>{
+      "indentation",
+      "commentStyle",
+      "enableYAMLCompatibility",
+      "dropNullPlaceholders",
+      "useSpecialFloats",
+      "emitUTF8",
+      "precision",
+      "precisionType",
+  };
+  for (auto si = settings_.begin(); si != settings_.end(); ++si) {
+    auto key = si.name();
+    if (valid_keys.count(key))
+      continue;
+    if (invalid)
+      (*invalid)[key] = *si;
+    else
+      return false;
+  }
+  return invalid ? invalid->empty() : true;
+}
+
+Value& StreamWriterBuilder::operator[](const String& key) {
+  return settings_[key];
+}
+// static
+void StreamWriterBuilder::setDefaults(Json::Value* settings) {
+  //! [StreamWriterBuilderDefaults]
+  (*settings)["commentStyle"] = "All";
+  (*settings)["indentation"] = "\t";
+  (*settings)["enableYAMLCompatibility"] = false;
+  (*settings)["dropNullPlaceholders"] = false;
+  (*settings)["useSpecialFloats"] = false;
+  (*settings)["emitUTF8"] = false;
+  (*settings)["precision"] = 17;
+  (*settings)["precisionType"] = "significant";
+  //! [StreamWriterBuilderDefaults]
+}
+
+String writeString(StreamWriter::Factory const& factory, Value const& root) {
+  OStringStream sout;
+  StreamWriterPtr const writer(factory.newStreamWriter());
+  writer->write(root, &sout);
+  return sout.str();
+}
+
+OStream& operator<<(OStream& sout, Value const& root) {
+  StreamWriterBuilder builder;
+  StreamWriterPtr const writer(builder.newStreamWriter());
+  writer->write(root, &sout);
+  return sout;
+}
+
+} // namespace Json