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423 lines
13 KiB
C++
423 lines
13 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) 2014-present Godot Engine contributors (see AUTHORS.md). */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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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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#pragma once
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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/typedefs.h"
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#ifdef _MSC_VER
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#include <intrin.h> // Needed for `__umulh` below.
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#endif
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template <typename F, typename S>
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struct Pair;
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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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_FORCE_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 = *chr++;
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while (c) {
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hash = ((hash << 5) + hash) ^ c; /* hash * 33 ^ c */
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c = *chr++;
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}
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return hash;
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}
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_FORCE_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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_FORCE_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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_FORCE_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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_FORCE_INLINE_ uint64_t hash64_murmur3_64(uint64_t key, uint64_t seed) {
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key ^= seed;
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key ^= key >> 33;
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key *= 0xff51afd7ed558ccd;
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key ^= key >> 33;
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key *= 0xc4ceb9fe1a85ec53;
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key ^= key >> 33;
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return key;
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}
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#define HASH_MURMUR3_SEED 0x7F07C65
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// Murmurhash3 32-bit version.
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// All MurmurHash versions are public domain software, and the author disclaims all copyright to their code.
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_FORCE_INLINE_ uint32_t hash_murmur3_one_32(uint32_t p_in, uint32_t p_seed = HASH_MURMUR3_SEED) {
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p_in *= 0xcc9e2d51;
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p_in = (p_in << 15) | (p_in >> 17);
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p_in *= 0x1b873593;
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p_seed ^= p_in;
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p_seed = (p_seed << 13) | (p_seed >> 19);
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p_seed = p_seed * 5 + 0xe6546b64;
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return p_seed;
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}
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_FORCE_INLINE_ uint32_t hash_murmur3_one_64(uint64_t p_in, uint32_t p_seed = HASH_MURMUR3_SEED) {
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p_seed = hash_murmur3_one_32(p_in & 0xFFFFFFFF, p_seed);
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return hash_murmur3_one_32(p_in >> 32, p_seed);
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}
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uint32_t hash_murmur3_one_float(float p_in, uint32_t p_seed = HASH_MURMUR3_SEED);
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uint32_t hash_murmur3_one_double(double p_in, uint32_t p_seed = HASH_MURMUR3_SEED);
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_FORCE_INLINE_ uint32_t hash_murmur3_one_real(real_t p_in, uint32_t p_seed = HASH_MURMUR3_SEED) {
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#ifdef REAL_T_IS_DOUBLE
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return hash_murmur3_one_double(p_in, p_seed);
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#else
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return hash_murmur3_one_float(p_in, p_seed);
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#endif
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}
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_FORCE_INLINE_ uint32_t hash_rotl32(uint32_t x, int8_t r) {
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return (x << r) | (x >> (32 - r));
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}
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_FORCE_INLINE_ uint32_t hash_fmix32(uint32_t h) {
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h ^= h >> 16;
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h *= 0x85ebca6b;
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h ^= h >> 13;
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h *= 0xc2b2ae35;
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h ^= h >> 16;
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return h;
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}
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uint32_t hash_murmur3_buffer(const void *key, int length, uint32_t seed = HASH_MURMUR3_SEED);
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uint32_t hash_djb2_one_float(double p_in, uint32_t p_prev = 5381);
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uint64_t hash_djb2_one_float_64(double p_in, uint64_t p_prev = 5381);
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_FORCE_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 <typename, typename = std::void_t<>>
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struct has_hash_method : std::false_type {};
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template <typename T>
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struct has_hash_method<T, std::void_t<std::is_same<decltype(std::declval<const T>().hash()), uint32_t>>> : std::true_type {};
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template <typename T>
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constexpr bool has_hash_method_v = has_hash_method<T>::value;
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template <typename T, typename = void>
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struct HashMapHasherDefaultImpl {
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};
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struct HashMapHasherDefault {
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template <typename T>
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static _FORCE_INLINE_ uint32_t hash(const T &p_type) {
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return HashMapHasherDefaultImpl<std::decay_t<T>>::hash(p_type);
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}
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};
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template <typename T>
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struct HashMapHasherDefaultImpl<T, std::enable_if_t<has_hash_method_v<T>>> {
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// For self hashing types.
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static _FORCE_INLINE_ uint32_t hash(const T &p_value) {
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return p_value.hash();
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}
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};
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template <typename T>
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struct HashMapHasherDefaultImpl<T *> {
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// For pointer types.
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static _FORCE_INLINE_ uint32_t hash(const T *p_pointer) { return hash_one_uint64((uint64_t)p_pointer); }
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};
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template <typename T>
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struct HashMapHasherDefaultImpl<T, std::enable_if_t<std::is_enum_v<T>>> {
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// For all enums.
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static _FORCE_INLINE_ uint32_t hash(T p_value) {
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return HashMapHasherDefaultImpl<std::underlying_type_t<T>>::hash(static_cast<std::underlying_type_t<T>>(p_value));
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}
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};
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template <>
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struct HashMapHasherDefaultImpl<char *> {
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static _FORCE_INLINE_ uint32_t hash(const char *p_cstr) { return hash_djb2(p_cstr); }
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};
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template <>
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struct HashMapHasherDefaultImpl<wchar_t> {
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static _FORCE_INLINE_ uint32_t hash(const wchar_t p_wchar) { return hash_fmix32(uint32_t(p_wchar)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<char16_t> {
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static _FORCE_INLINE_ uint32_t hash(const char16_t p_uchar) { return hash_fmix32(uint32_t(p_uchar)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<char32_t> {
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static _FORCE_INLINE_ uint32_t hash(const char32_t p_uchar) { return hash_fmix32(uint32_t(p_uchar)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<uint64_t> {
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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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};
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template <>
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struct HashMapHasherDefaultImpl<int64_t> {
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static _FORCE_INLINE_ uint32_t hash(const int64_t p_int) { return hash_one_uint64(uint64_t(p_int)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<float> {
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static _FORCE_INLINE_ uint32_t hash(const float p_float) { return hash_murmur3_one_float(p_float); }
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};
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template <>
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struct HashMapHasherDefaultImpl<double> {
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static _FORCE_INLINE_ uint32_t hash(const double p_double) { return hash_murmur3_one_double(p_double); }
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};
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template <>
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struct HashMapHasherDefaultImpl<uint32_t> {
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static _FORCE_INLINE_ uint32_t hash(const uint32_t p_int) { return hash_fmix32(p_int); }
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};
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template <>
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struct HashMapHasherDefaultImpl<int32_t> {
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static _FORCE_INLINE_ uint32_t hash(const int32_t p_int) { return hash_fmix32(uint32_t(p_int)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<uint16_t> {
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static _FORCE_INLINE_ uint32_t hash(const uint16_t p_int) { return hash_fmix32(uint32_t(p_int)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<int16_t> {
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static _FORCE_INLINE_ uint32_t hash(const int16_t p_int) { return hash_fmix32(uint32_t(p_int)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<uint8_t> {
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static _FORCE_INLINE_ uint32_t hash(const uint8_t p_int) { return hash_fmix32(uint32_t(p_int)); }
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};
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template <>
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struct HashMapHasherDefaultImpl<int8_t> {
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static _FORCE_INLINE_ uint32_t hash(const int8_t p_int) { return hash_fmix32(uint32_t(p_int)); }
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};
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template <typename F, typename S>
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struct HashMapHasherDefaultImpl<Pair<F, S>> {
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static _FORCE_INLINE_ uint32_t hash(const Pair<F, S> &p_pair) {
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uint64_t h1 = HashMapHasherDefault::hash(p_pair.first);
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uint64_t h2 = HashMapHasherDefault::hash(p_pair.second);
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return hash_one_uint64((h1 << 32) | h2);
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}
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};
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template <typename, typename = std::void_t<>>
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struct has_is_same_method : std::false_type {};
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template <typename T>
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struct has_is_same_method<T, std::void_t<std::is_same<decltype(std::declval<const T>().is_same(std::declval<const T>())), uint32_t>>> : std::true_type {};
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template <typename T>
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constexpr bool has_is_same_method_v = has_is_same_method<T>::value;
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struct HashHasher {
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static _FORCE_INLINE_ uint32_t hash(const int32_t hash) { return hash; }
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static _FORCE_INLINE_ uint32_t hash(const uint32_t hash) { return hash; }
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static _FORCE_INLINE_ uint64_t hash(const int64_t hash) { return hash; }
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static _FORCE_INLINE_ uint64_t hash(const uint64_t hash) { return hash; }
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};
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template <typename T, typename = void>
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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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};
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template <>
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struct HashMapComparatorDefault<float> {
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static bool compare(const float &p_lhs, const float &p_rhs) {
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return Math::is_same(p_lhs, p_rhs);
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}
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};
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template <>
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struct HashMapComparatorDefault<double> {
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static bool compare(const double &p_lhs, const double &p_rhs) {
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return Math::is_same(p_lhs, p_rhs);
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}
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};
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template <typename T>
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struct HashMapComparatorDefault<T, std::enable_if_t<has_is_same_method_v<T>>> {
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// For self comparing types.
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static bool compare(const T &p_lhs, const T &p_rhs) {
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return p_lhs.is_same(p_rhs);
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}
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};
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constexpr uint32_t HASH_TABLE_SIZE_MAX = 29;
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inline constexpr uint32_t hash_table_size_primes[HASH_TABLE_SIZE_MAX] = {
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5,
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13,
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23,
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47,
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97,
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193,
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389,
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769,
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1543,
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3079,
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6151,
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12289,
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24593,
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49157,
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98317,
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196613,
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393241,
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786433,
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1572869,
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3145739,
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6291469,
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12582917,
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25165843,
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50331653,
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100663319,
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201326611,
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402653189,
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805306457,
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1610612741,
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};
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// Computed with elem_i = UINT64_C (0 x FFFFFFFF FFFFFFFF ) / d_i + 1, where d_i is the i-th element of the above array.
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inline constexpr uint64_t hash_table_size_primes_inv[HASH_TABLE_SIZE_MAX] = {
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3689348814741910324,
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1418980313362273202,
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802032351030850071,
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392483916461905354,
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190172619316593316,
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95578984837873325,
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47420935922132524,
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23987963684927896,
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11955116055547344,
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5991147799191151,
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2998982941588287,
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1501077717772769,
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750081082979285,
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375261795343686,
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187625172388393,
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93822606204624,
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46909513691883,
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23456218233098,
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11728086747027,
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5864041509391,
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2932024948977,
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1466014921160,
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733007198436,
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366503839517,
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183251896093,
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91625960335,
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45812983922,
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22906489714,
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11453246088
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};
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/**
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* Fastmod computes ( n mod d ) given the precomputed c much faster than n % d.
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* The implementation of fastmod is based on the following paper by Daniel Lemire et al.
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* Faster Remainder by Direct Computation: Applications to Compilers and Software Libraries
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* https://arxiv.org/abs/1902.01961
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*/
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static _FORCE_INLINE_ uint32_t fastmod(const uint32_t n, const uint64_t c, const uint32_t d) {
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#if defined(_MSC_VER)
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// Returns the upper 64 bits of the product of two 64-bit unsigned integers.
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// This intrinsic function is required since MSVC does not support unsigned 128-bit integers.
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#if defined(_M_X64) || defined(_M_ARM64)
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return __umulh(c * n, d);
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#else
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// Fallback to the slower method for 32-bit platforms.
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return n % d;
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#endif // _M_X64 || _M_ARM64
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#else
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#ifdef __SIZEOF_INT128__
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// Prevent compiler warning, because we know what we are doing.
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uint64_t lowbits = c * n;
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__extension__ typedef unsigned __int128 uint128;
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return static_cast<uint64_t>(((uint128)lowbits * d) >> 64);
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#else
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// Fallback to the slower method if no 128-bit unsigned integer type is available.
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return n % d;
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#endif // __SIZEOF_INT128__
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#endif // _MSC_VER
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}
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