200 lines
7.1 KiB
C++
200 lines
7.1 KiB
C++
/*************************************************************************/
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/* hashfuncs.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef HASHFUNCS_H
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#define HASHFUNCS_H
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#include "core/math/math_defs.h"
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#include "core/math/math_funcs.h"
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#include "core/object/object_id.h"
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#include "core/string/node_path.h"
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#include "core/string/string_name.h"
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#include "core/string/ustring.h"
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#include "core/templates/rid.h"
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#include "core/typedefs.h"
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/**
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* Hashing functions
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*/
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/**
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* DJB2 Hash function
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* @param C String
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* @return 32-bits hashcode
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*/
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static inline uint32_t hash_djb2(const char *p_cstr) {
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const unsigned char *chr = (const unsigned char *)p_cstr;
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uint32_t hash = 5381;
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uint32_t c;
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while ((c = *chr++)) {
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hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
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}
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return hash;
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}
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static inline uint32_t hash_djb2_buffer(const uint8_t *p_buff, int p_len, uint32_t p_prev = 5381) {
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uint32_t hash = p_prev;
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for (int i = 0; i < p_len; i++) {
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hash = ((hash << 5) + hash) + p_buff[i]; /* hash * 33 + c */
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}
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return hash;
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}
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static inline uint32_t hash_djb2_one_32(uint32_t p_in, uint32_t p_prev = 5381) {
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return ((p_prev << 5) + p_prev) + p_in;
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}
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/**
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* Thomas Wang's 64-bit to 32-bit Hash function:
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* https://web.archive.org/web/20071223173210/https:/www.concentric.net/~Ttwang/tech/inthash.htm
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*
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* @param p_int - 64-bit unsigned integer key to be hashed
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* @return unsigned 32-bit value representing hashcode
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*/
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static inline uint32_t hash_one_uint64(const uint64_t p_int) {
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uint64_t v = p_int;
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v = (~v) + (v << 18); // v = (v << 18) - v - 1;
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v = v ^ (v >> 31);
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v = v * 21; // v = (v + (v << 2)) + (v << 4);
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v = v ^ (v >> 11);
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v = v + (v << 6);
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v = v ^ (v >> 22);
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return uint32_t(v);
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}
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static inline uint32_t hash_djb2_one_float(double p_in, uint32_t p_prev = 5381) {
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union {
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double d;
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uint64_t i;
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} u;
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// Normalize +/- 0.0 and NaN values so they hash the same.
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if (p_in == 0.0f) {
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u.d = 0.0;
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} else if (Math::is_nan(p_in)) {
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u.d = NAN;
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} else {
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u.d = p_in;
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}
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return ((p_prev << 5) + p_prev) + hash_one_uint64(u.i);
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}
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template <class T>
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static inline uint32_t make_uint32_t(T p_in) {
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union {
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T t;
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uint32_t _u32;
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} _u;
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_u._u32 = 0;
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_u.t = p_in;
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return _u._u32;
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}
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static inline uint64_t hash_djb2_one_float_64(double p_in, uint64_t p_prev = 5381) {
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union {
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double d;
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uint64_t i;
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} u;
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// Normalize +/- 0.0 and NaN values so they hash the same.
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if (p_in == 0.0f) {
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u.d = 0.0;
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} else if (Math::is_nan(p_in)) {
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u.d = NAN;
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} else {
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u.d = p_in;
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}
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return ((p_prev << 5) + p_prev) + u.i;
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}
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static inline uint64_t hash_djb2_one_64(uint64_t p_in, uint64_t p_prev = 5381) {
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return ((p_prev << 5) + p_prev) + p_in;
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}
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template <class T>
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static inline uint64_t make_uint64_t(T p_in) {
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union {
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T t;
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uint64_t _u64;
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} _u;
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_u._u64 = 0; // in case p_in is smaller
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_u.t = p_in;
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return _u._u64;
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}
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struct HashMapHasherDefault {
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static _FORCE_INLINE_ uint32_t hash(const String &p_string) { return p_string.hash(); }
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static _FORCE_INLINE_ uint32_t hash(const char *p_cstr) { return hash_djb2(p_cstr); }
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static _FORCE_INLINE_ uint32_t hash(const uint64_t p_int) { return hash_one_uint64(p_int); }
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static _FORCE_INLINE_ uint32_t hash(const ObjectID &p_id) { return hash_one_uint64(p_id); }
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static _FORCE_INLINE_ uint32_t hash(const int64_t p_int) { return hash(uint64_t(p_int)); }
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static _FORCE_INLINE_ uint32_t hash(const float p_float) { return hash_djb2_one_float(p_float); }
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static _FORCE_INLINE_ uint32_t hash(const double p_double) { return hash_djb2_one_float(p_double); }
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static _FORCE_INLINE_ uint32_t hash(const uint32_t p_int) { return p_int; }
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static _FORCE_INLINE_ uint32_t hash(const int32_t p_int) { return (uint32_t)p_int; }
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static _FORCE_INLINE_ uint32_t hash(const uint16_t p_int) { return p_int; }
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static _FORCE_INLINE_ uint32_t hash(const int16_t p_int) { return (uint32_t)p_int; }
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static _FORCE_INLINE_ uint32_t hash(const uint8_t p_int) { return p_int; }
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static _FORCE_INLINE_ uint32_t hash(const int8_t p_int) { return (uint32_t)p_int; }
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static _FORCE_INLINE_ uint32_t hash(const wchar_t p_wchar) { return (uint32_t)p_wchar; }
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static _FORCE_INLINE_ uint32_t hash(const char16_t p_uchar) { return (uint32_t)p_uchar; }
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static _FORCE_INLINE_ uint32_t hash(const char32_t p_uchar) { return (uint32_t)p_uchar; }
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static _FORCE_INLINE_ uint32_t hash(const RID &p_rid) { return hash_one_uint64(p_rid.get_id()); }
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static _FORCE_INLINE_ uint32_t hash(const StringName &p_string_name) { return p_string_name.hash(); }
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static _FORCE_INLINE_ uint32_t hash(const NodePath &p_path) { return p_path.hash(); }
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//static _FORCE_INLINE_ uint32_t hash(const void* p_ptr) { return uint32_t(uint64_t(p_ptr))*(0x9e3779b1L); }
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};
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template <typename T>
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struct HashMapComparatorDefault {
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static bool compare(const T &p_lhs, const T &p_rhs) {
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return p_lhs == p_rhs;
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}
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bool compare(const float &p_lhs, const float &p_rhs) {
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return (p_lhs == p_rhs) || (Math::is_nan(p_lhs) && Math::is_nan(p_rhs));
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}
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bool compare(const double &p_lhs, const double &p_rhs) {
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return (p_lhs == p_rhs) || (Math::is_nan(p_lhs) && Math::is_nan(p_rhs));
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}
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};
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#endif // HASHFUNCS_H
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