Update libwebp to 0.6.1

* lossless performance and compression improvements + a new 'cruncher' mode (-m 6 -q 100)
* ARM performance improvements with clang (15-20% w/ndk r15c)
* webp-js: emscripten/webassembly based javascript decoder
* miscellaneous bug & build fixes

1 files changed, 125 insertions, 0 deletions

diff --git a/thirdparty/libwebp/src/enc/histogram_enc.h b/thirdparty/libwebp/src/enc/histogram_enc.h
new file mode 100644
index 0000000000..15b1fbda34
--- /dev/null
+++ b/thirdparty/libwebp/src/enc/histogram_enc.h
@@ -0,0 +1,125 @@
+// Copyright 2012 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Author: Jyrki Alakuijala (jyrki@google.com)
+//
+// Models the histograms of literal and distance codes.
+
+#ifndef WEBP_ENC_HISTOGRAM_ENC_H_
+#define WEBP_ENC_HISTOGRAM_ENC_H_
+
+#include <string.h>
+
+#include "src/enc/backward_references_enc.h"
+#include "src/webp/format_constants.h"
+#include "src/webp/types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Not a trivial literal symbol.
+#define VP8L_NON_TRIVIAL_SYM (0xffffffff)
+
+// A simple container for histograms of data.
+typedef struct {
+  // literal_ contains green literal, palette-code and
+  // copy-length-prefix histogram
+  uint32_t* literal_;         // Pointer to the allocated buffer for literal.
+  uint32_t red_[NUM_LITERAL_CODES];
+  uint32_t blue_[NUM_LITERAL_CODES];
+  uint32_t alpha_[NUM_LITERAL_CODES];
+  // Backward reference prefix-code histogram.
+  uint32_t distance_[NUM_DISTANCE_CODES];
+  int palette_code_bits_;
+  uint32_t trivial_symbol_;  // True, if histograms for Red, Blue & Alpha
+                             // literal symbols are single valued.
+  double bit_cost_;          // cached value of bit cost.
+  double literal_cost_;      // Cached values of dominant entropy costs:
+  double red_cost_;          // literal, red & blue.
+  double blue_cost_;
+} VP8LHistogram;
+
+// Collection of histograms with fixed capacity, allocated as one
+// big memory chunk. Can be destroyed by calling WebPSafeFree().
+typedef struct {
+  int size;         // number of slots currently in use
+  int max_size;     // maximum capacity
+  VP8LHistogram** histograms;
+} VP8LHistogramSet;
+
+// Create the histogram.
+//
+// The input data is the PixOrCopy data, which models the literals, stop
+// codes and backward references (both distances and lengths).  Also: if
+// palette_code_bits is >= 0, initialize the histogram with this value.
+void VP8LHistogramCreate(VP8LHistogram* const p,
+                         const VP8LBackwardRefs* const refs,
+                         int palette_code_bits);
+
+// Return the size of the histogram for a given palette_code_bits.
+int VP8LGetHistogramSize(int palette_code_bits);
+
+// Set the palette_code_bits and reset the stats.
+void VP8LHistogramInit(VP8LHistogram* const p, int palette_code_bits);
+
+// Collect all the references into a histogram (without reset)
+void VP8LHistogramStoreRefs(const VP8LBackwardRefs* const refs,
+                            VP8LHistogram* const histo);
+
+// Free the memory allocated for the histogram.
+void VP8LFreeHistogram(VP8LHistogram* const histo);
+
+// Free the memory allocated for the histogram set.
+void VP8LFreeHistogramSet(VP8LHistogramSet* const histo);
+
+// Allocate an array of pointer to histograms, allocated and initialized
+// using 'cache_bits'. Return NULL in case of memory error.
+VP8LHistogramSet* VP8LAllocateHistogramSet(int size, int cache_bits);
+
+// Allocate and initialize histogram object with specified 'cache_bits'.
+// Returns NULL in case of memory error.
+// Special case of VP8LAllocateHistogramSet, with size equals 1.
+VP8LHistogram* VP8LAllocateHistogram(int cache_bits);
+
+// Accumulate a token 'v' into a histogram.
+void VP8LHistogramAddSinglePixOrCopy(VP8LHistogram* const histo,
+                                     const PixOrCopy* const v,
+                                     int (*const distance_modifier)(int, int),
+                                     int distance_modifier_arg0);
+
+static WEBP_INLINE int VP8LHistogramNumCodes(int palette_code_bits) {
+  return NUM_LITERAL_CODES + NUM_LENGTH_CODES +
+      ((palette_code_bits > 0) ? (1 << palette_code_bits) : 0);
+}
+
+// Builds the histogram image.
+int VP8LGetHistoImageSymbols(int xsize, int ysize,
+                             const VP8LBackwardRefs* const refs,
+                             int quality, int low_effort,
+                             int histogram_bits, int cache_bits,
+                             VP8LHistogramSet* const image_in,
+                             VP8LHistogram* const tmp_histo,
+                             uint16_t* const histogram_symbols);
+
+// Returns the entropy for the symbols in the input array.
+// Also sets trivial_symbol to the code value, if the array has only one code
+// value. Otherwise, set it to VP8L_NON_TRIVIAL_SYM.
+double VP8LBitsEntropy(const uint32_t* const array, int n,
+                       uint32_t* const trivial_symbol);
+
+// Estimate how many bits the combined entropy of literals and distance
+// approximately maps to.
+double VP8LHistogramEstimateBits(const VP8LHistogram* const p);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // WEBP_ENC_HISTOGRAM_ENC_H_