Merge pull request #10318 from endragor/ordered-hash-map

Implement OrderedHashMap

1 files changed, 315 insertions, 0 deletions

diff --git a/core/ordered_hash_map.h b/core/ordered_hash_map.h
new file mode 100644
index 0000000000..3e619d2b2e
--- /dev/null
+++ b/core/ordered_hash_map.h
@@ -0,0 +1,315 @@
+/*************************************************************************/
+/*  ordered_hash_map.h                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                    http://www.godotengine.org                         */
+/*************************************************************************/
+/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* 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.                */
+/*************************************************************************/
+#ifndef ORDERED_HASH_MAP_H
+#define ORDERED_HASH_MAP_H
+
+#include "hash_map.h"
+#include "list.h"
+#include "pair.h"
+
+/**
+ * A hash map which allows to iterate elements in insertion order.
+ * Insertion, lookup, deletion have O(1) complexity.
+ * The API aims to be consistent with Map rather than HashMap, because the
+ * former is more frequently used and is more coherent with the rest of the
+ * codebase.
+ * Deletion during iteration is safe and will preserve the order.
+ */
+template <class K, class V, class Hasher = HashMapHasherDefault, class Comparator = HashMapComparatorDefault<K>, uint8_t MIN_HASH_TABLE_POWER = 3, uint8_t RELATIONSHIP = 8>
+class OrderedHashMap {
+	typedef List<Pair<const K *, V> > InternalList;
+	typedef HashMap<K, typename InternalList::Element *, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP> InternalMap;
+
+	InternalList list;
+	InternalMap map;
+
+public:
+	class Element {
+		friend class OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>;
+
+		typename InternalList::Element *list_element;
+		typename InternalList::Element *next_element;
+		typename InternalList::Element *prev_element;
+
+		Element(typename InternalList::Element *p_element) {
+			list_element = p_element;
+
+			if (list_element) {
+				next_element = list_element->next();
+				prev_element = list_element->prev();
+			}
+		}
+
+	public:
+		_FORCE_INLINE_ Element()
+			: list_element(NULL), next_element(NULL), prev_element(NULL) {
+		}
+
+		Element next() const {
+			return Element(next_element);
+		}
+
+		Element prev() const {
+			return Element(prev_element);
+		}
+
+		Element(const Element &other)
+			: list_element(other.list_element),
+			  prev_element(other.prev_element),
+			  next_element(other.next_element) {
+		}
+
+		Element &operator=(const Element &other) {
+			list_element = other.list_element;
+			next_element = other.next_element;
+			prev_element = other.prev_element;
+			return *this;
+		}
+
+		friend bool operator==(const Element &, const Element &);
+		friend bool operator!=(const Element &, const Element &);
+
+		operator bool() const {
+			return (list_element != NULL);
+		}
+
+		const K &key() const {
+			CRASH_COND(!list_element);
+			return *(list_element->get().first);
+		};
+
+		V &value() {
+			CRASH_COND(!list_element);
+			return list_element->get().second;
+		};
+
+		const V &value() const {
+			CRASH_COND(!list_element);
+			return list_element->get().second;
+		};
+
+		V &get() {
+			CRASH_COND(!list_element);
+			return list_element->get().second;
+		};
+
+		const V &get() const {
+			CRASH_COND(!list_element);
+			return list_element->get().second;
+		};
+	};
+
+	class ConstElement {
+		friend class OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>;
+
+		const typename InternalList::Element *list_element;
+
+		ConstElement(const typename InternalList::Element *p_element)
+			: list_element(p_element) {
+		}
+
+	public:
+		_FORCE_INLINE_ ConstElement()
+			: list_element(NULL) {
+		}
+
+		ConstElement(const ConstElement &other)
+			: list_element(other.list_element) {
+		}
+
+		ConstElement &operator=(const ConstElement &other) {
+			list_element = other.list_element;
+			return *this;
+		}
+
+		ConstElement next() const {
+			return ConstElement(list_element ? list_element->next() : NULL);
+		}
+
+		ConstElement prev() const {
+			return ConstElement(list_element ? list_element->prev() : NULL);
+		}
+
+		friend bool operator==(const ConstElement &, const ConstElement &);
+		friend bool operator!=(const ConstElement &, const ConstElement &);
+
+		operator bool() const {
+			return (list_element != NULL);
+		}
+
+		const K &key() const {
+			CRASH_COND(!list_element);
+			return *(list_element->get().first);
+		};
+
+		const V &value() const {
+			CRASH_COND(!list_element);
+			return list_element->get().second;
+		};
+
+		const V &get() const {
+			CRASH_COND(!list_element);
+			return list_element->get().second;
+		};
+	};
+
+	ConstElement find(const K &p_key) const {
+		typename InternalList::Element **list_element = map.getptr(p_key);
+		if (list_element) {
+			return ConstElement(*list_element);
+		}
+		return ConstElement(NULL);
+	}
+
+	Element find(const K &p_key) {
+		typename InternalList::Element **list_element = map.getptr(p_key);
+		if (list_element) {
+			return Element(*list_element);
+		}
+		return Element(NULL);
+	}
+
+	Element insert(const K &p_key, const V &p_value) {
+		typename InternalList::Element **list_element = map.getptr(p_key);
+		if (list_element) {
+			(*list_element)->get().second = p_value;
+			return Element(*list_element);
+		}
+		typename InternalList::Element *new_element = list.push_back(Pair<const K *, V>(NULL, p_value));
+		typename InternalMap::Element *e = map.set(p_key, new_element);
+		new_element->get().first = &e->key();
+
+		return Element(new_element);
+	}
+
+	void erase(Element &p_element) {
+		map.erase(p_element.key());
+		list.erase(p_element.list_element);
+		p_element.list_element = NULL;
+	}
+
+	bool erase(const K &p_key) {
+		typename InternalList::Element **list_element = map.getptr(p_key);
+		if (list_element) {
+			list.erase(*list_element);
+			map.erase(p_key);
+			return true;
+		}
+		return false;
+	}
+
+	inline bool has(const K &p_key) const {
+		return map.has(p_key);
+	}
+
+	const V &operator[](const K &p_key) const {
+		ConstElement e = find(p_key);
+		CRASH_COND(!e);
+		return e.value();
+	}
+
+	V &operator[](const K &p_key) {
+		Element e = find(p_key);
+		if (!e) {
+			// consistent with Map behaviour
+			e = insert(p_key, V());
+		}
+		return e.value();
+	}
+
+	inline Element front() {
+		return Element(list.front());
+	}
+
+	inline Element back() {
+		return Element(list.back());
+	}
+
+	inline ConstElement front() const {
+		return ConstElement(list.front());
+	}
+
+	inline ConstElement back() const {
+		return ConstElement(list.back());
+	}
+
+	inline bool empty() const { return list.empty(); }
+	inline int size() const { return list.size(); }
+
+	void clear() {
+		map.clear();
+		list.clear();
+	}
+
+private:
+	void _copy_from(const OrderedHashMap &p_map) {
+		for (ConstElement E = p_map.front(); E; E = E.next()) {
+			insert(E.key(), E.value());
+		}
+	}
+
+public:
+	void operator=(const OrderedHashMap &p_map) {
+		_copy_from(p_map);
+	}
+
+	OrderedHashMap(const OrderedHashMap &p_map) {
+		_copy_from(p_map);
+	}
+
+	_FORCE_INLINE_ OrderedHashMap() {
+	}
+};
+
+template <class K, class V, class Hasher, class Comparator, uint8_t MIN_HASH_TABLE_POWER, uint8_t RELATIONSHIP>
+bool operator==(const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::Element &first,
+		const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::Element &second) {
+	return (first.list_element == second.list_element);
+}
+
+template <class K, class V, class Hasher, class Comparator, uint8_t MIN_HASH_TABLE_POWER, uint8_t RELATIONSHIP>
+bool operator!=(const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::Element &first,
+		const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::Element &second) {
+	return (first.list_element != second.list_element);
+}
+
+template <class K, class V, class Hasher, class Comparator, uint8_t MIN_HASH_TABLE_POWER, uint8_t RELATIONSHIP>
+bool operator==(const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::ConstElement &first,
+		const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::ConstElement &second) {
+	return (first.list_element == second.list_element);
+}
+
+template <class K, class V, class Hasher, class Comparator, uint8_t MIN_HASH_TABLE_POWER, uint8_t RELATIONSHIP>
+bool operator!=(const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::ConstElement &first,
+		const typename OrderedHashMap<K, V, Hasher, Comparator, MIN_HASH_TABLE_POWER, RELATIONSHIP>::ConstElement &second) {
+	return (first.list_element != second.list_element);
+}
+
+#endif // ORDERED_HASH_MAP_H
\ No newline at end of file