/*************************************************************************/
/*  vmap.h                                                               */
/*************************************************************************/
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/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#ifndef VMAP_H
#define VMAP_H

#include "core/templates/cowdata.h"
#include "core/typedefs.h"

template <class T, class V>
class VMap {
public:
	struct Pair {
		T key;
		V value;

		_FORCE_INLINE_ Pair() {}

		_FORCE_INLINE_ Pair(const T &p_key, const V &p_value) {
			key = p_key;
			value = p_value;
		}
	};

private:
	CowData<Pair> _cowdata;

	_FORCE_INLINE_ int _find(const T &p_val, bool &r_exact) const {
		r_exact = false;
		if (_cowdata.is_empty()) {
			return 0;
		}

		int low = 0;
		int high = _cowdata.size() - 1;
		const Pair *a = _cowdata.ptr();
		int middle = 0;

#ifdef DEBUG_ENABLED
		if (low > high) {
			ERR_PRINT("low > high, this may be a bug");
		}
#endif
		while (low <= high) {
			middle = (low + high) / 2;

			if (p_val < a[middle].key) {
				high = middle - 1; //search low end of array
			} else if (a[middle].key < p_val) {
				low = middle + 1; //search high end of array
			} else {
				r_exact = true;
				return middle;
			}
		}

		//return the position where this would be inserted
		if (a[middle].key < p_val) {
			middle++;
		}
		return middle;
	}

	_FORCE_INLINE_ int _find_exact(const T &p_val) const {
		if (_cowdata.is_empty()) {
			return -1;
		}

		int low = 0;
		int high = _cowdata.size() - 1;
		int middle;
		const Pair *a = _cowdata.ptr();

		while (low <= high) {
			middle = (low + high) / 2;

			if (p_val < a[middle].key) {
				high = middle - 1; //search low end of array
			} else if (a[middle].key < p_val) {
				low = middle + 1; //search high end of array
			} else {
				return middle;
			}
		}

		return -1;
	}

public:
	int insert(const T &p_key, const V &p_val) {
		bool exact;
		int pos = _find(p_key, exact);
		if (exact) {
			_cowdata.get_m(pos).value = p_val;
			return pos;
		}
		_cowdata.insert(pos, Pair(p_key, p_val));
		return pos;
	}

	bool has(const T &p_val) const {
		return _find_exact(p_val) != -1;
	}

	void erase(const T &p_val) {
		int pos = _find_exact(p_val);
		if (pos < 0) {
			return;
		}
		_cowdata.remove_at(pos);
	}

	int find(const T &p_val) const {
		return _find_exact(p_val);
	}

	int find_nearest(const T &p_val) const {
		bool exact;
		return _find(p_val, exact);
	}

	_FORCE_INLINE_ int size() const { return _cowdata.size(); }
	_FORCE_INLINE_ bool is_empty() const { return _cowdata.is_empty(); }

	const Pair *get_array() const {
		return _cowdata.ptr();
	}

	Pair *get_array() {
		return _cowdata.ptrw();
	}

	const V &getv(int p_index) const {
		return _cowdata.get(p_index).value;
	}

	V &getv(int p_index) {
		return _cowdata.get_m(p_index).value;
	}

	const T &getk(int p_index) const {
		return _cowdata.get(p_index).key;
	}

	T &getk(int p_index) {
		return _cowdata.get_m(p_index).key;
	}

	inline const V &operator[](const T &p_key) const {
		int pos = _find_exact(p_key);

		CRASH_COND(pos < 0);

		return _cowdata.get(pos).value;
	}

	inline V &operator[](const T &p_key) {
		int pos = _find_exact(p_key);
		if (pos < 0) {
			pos = insert(p_key, V());
		}

		return _cowdata.get_m(pos).value;
	}

	_FORCE_INLINE_ VMap() {}
	_FORCE_INLINE_ VMap(const VMap &p_from) { _cowdata._ref(p_from._cowdata); }

	inline VMap &operator=(const VMap &p_from) {
		_cowdata._ref(p_from._cowdata);
		return *this;
	}
};

#endif // VMAP_H