/**************************************************************************/
/* hashfuncs.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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. */
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#pragma once
#include "core/math/math_defs.h"
#include "core/math/math_funcs.h"
#include "core/typedefs.h"
#ifdef _MSC_VER
#include <intrin.h> // Needed for `__umulh` below.
#endif
template <typename F, typename S>
struct Pair;
/**
* Hashing functions
*/
/**
* DJB2 Hash function
* @param C String
* @return 32-bits hashcode
*/
_FORCE_INLINE_ uint32_t hash_djb2(const char *p_cstr) {
const unsigned char *chr = (const unsigned char *)p_cstr;
uint32_t hash = 5381;
uint32_t c = *chr++;
while (c) {
hash = ((hash << 5) + hash) ^ c; /* hash * 33 ^ c */
c = *chr++;
}
return hash;
}
_FORCE_INLINE_ uint32_t hash_djb2_buffer(const uint8_t *p_buff, int p_len, uint32_t p_prev = 5381) {
uint32_t hash = p_prev;
for (int i = 0; i < p_len; i++) {
hash = ((hash << 5) + hash) ^ p_buff[i]; /* hash * 33 + c */
}
return hash;
}
_FORCE_INLINE_ uint32_t hash_djb2_one_32(uint32_t p_in, uint32_t p_prev = 5381) {
return ((p_prev << 5) + p_prev) ^ p_in;
}
/**
* Thomas Wang's 64-bit to 32-bit Hash function:
* https://web.archive.org/web/20071223173210/https:/www.concentric.net/~Ttwang/tech/inthash.htm
*
* @param p_int - 64-bit unsigned integer key to be hashed
* @return unsigned 32-bit value representing hashcode
*/
_FORCE_INLINE_ uint32_t hash_one_uint64(const uint64_t p_int) {
uint64_t v = p_int;
v = (~v) + (v << 18); // v = (v << 18) - v - 1;
v = v ^ (v >> 31);
v = v * 21; // v = (v + (v << 2)) + (v << 4);
v = v ^ (v >> 11);
v = v + (v << 6);
v = v ^ (v >> 22);
return uint32_t(v);
}
_FORCE_INLINE_ uint64_t hash64_murmur3_64(uint64_t key, uint64_t seed) {
key ^= seed;
key ^= key >> 33;
key *= 0xff51afd7ed558ccd;
key ^= key >> 33;
key *= 0xc4ceb9fe1a85ec53;
key ^= key >> 33;
return key;
}
#define HASH_MURMUR3_SEED 0x7F07C65
// Murmurhash3 32-bit version.
// All MurmurHash versions are public domain software, and the author disclaims all copyright to their code.
_FORCE_INLINE_ uint32_t hash_murmur3_one_32(uint32_t p_in, uint32_t p_seed = HASH_MURMUR3_SEED) {
p_in *= 0xcc9e2d51;
p_in = (p_in << 15) | (p_in >> 17);
p_in *= 0x1b873593;
p_seed ^= p_in;
p_seed = (p_seed << 13) | (p_seed >> 19);
p_seed = p_seed * 5 + 0xe6546b64;
return p_seed;
}
_FORCE_INLINE_ uint32_t hash_murmur3_one_64(uint64_t p_in, uint32_t p_seed = HASH_MURMUR3_SEED) {
p_seed = hash_murmur3_one_32(p_in & 0xFFFFFFFF, p_seed);
return hash_murmur3_one_32(p_in >> 32, p_seed);
}
uint32_t hash_murmur3_one_float(float p_in, uint32_t p_seed = HASH_MURMUR3_SEED);
uint32_t hash_murmur3_one_double(double p_in, uint32_t p_seed = HASH_MURMUR3_SEED);
_FORCE_INLINE_ uint32_t hash_murmur3_one_real(real_t p_in, uint32_t p_seed = HASH_MURMUR3_SEED) {
#ifdef REAL_T_IS_DOUBLE
return hash_murmur3_one_double(p_in, p_seed);
#else
return hash_murmur3_one_float(p_in, p_seed);
#endif
}
_FORCE_INLINE_ uint32_t hash_rotl32(uint32_t x, int8_t r) {
return (x << r) | (x >> (32 - r));
}
_FORCE_INLINE_ uint32_t hash_fmix32(uint32_t h) {
h ^= h >> 16;
h *= 0x85ebca6b;
h ^= h >> 13;
h *= 0xc2b2ae35;
h ^= h >> 16;
return h;
}
uint32_t hash_murmur3_buffer(const void *key, int length, uint32_t seed = HASH_MURMUR3_SEED);
uint32_t hash_djb2_one_float(double p_in, uint32_t p_prev = 5381);
uint64_t hash_djb2_one_float_64(double p_in, uint64_t p_prev = 5381);
_FORCE_INLINE_ uint64_t hash_djb2_one_64(uint64_t p_in, uint64_t p_prev = 5381) {
return ((p_prev << 5) + p_prev) ^ p_in;
}
template <typename, typename = std::void_t<>>
struct has_hash_method : std::false_type {};
template <typename T>
struct has_hash_method<T, std::void_t<std::is_same<decltype(std::declval<const T>().hash()), uint32_t>>> : std::true_type {};
template <typename T>
constexpr bool has_hash_method_v = has_hash_method<T>::value;
template <typename T, typename = void>
struct HashMapHasherDefaultImpl {
};
struct HashMapHasherDefault {
template <typename T>
static _FORCE_INLINE_ uint32_t hash(const T &p_type) {
return HashMapHasherDefaultImpl<std::decay_t<T>>::hash(p_type);
}
};
template <typename T>
struct HashMapHasherDefaultImpl<T, std::enable_if_t<has_hash_method_v<T>>> {
// For self hashing types.
static _FORCE_INLINE_ uint32_t hash(const T &p_value) {
return p_value.hash();
}
};
template <typename T>
struct HashMapHasherDefaultImpl<T *> {
// For pointer types.
static _FORCE_INLINE_ uint32_t hash(const T *p_pointer) { return hash_one_uint64((uint64_t)p_pointer); }
};
template <typename T>
struct HashMapHasherDefaultImpl<T, std::enable_if_t<std::is_enum_v<T>>> {
// For all enums.
static _FORCE_INLINE_ uint32_t hash(T p_value) {
return HashMapHasherDefaultImpl<std::underlying_type_t<T>>::hash(static_cast<std::underlying_type_t<T>>(p_value));
}
};
template <>
struct HashMapHasherDefaultImpl<char *> {
static _FORCE_INLINE_ uint32_t hash(const char *p_cstr) { return hash_djb2(p_cstr); }
};
template <>
struct HashMapHasherDefaultImpl<wchar_t> {
static _FORCE_INLINE_ uint32_t hash(const wchar_t p_wchar) { return hash_fmix32(uint32_t(p_wchar)); }
};
template <>
struct HashMapHasherDefaultImpl<char16_t> {
static _FORCE_INLINE_ uint32_t hash(const char16_t p_uchar) { return hash_fmix32(uint32_t(p_uchar)); }
};
template <>
struct HashMapHasherDefaultImpl<char32_t> {
static _FORCE_INLINE_ uint32_t hash(const char32_t p_uchar) { return hash_fmix32(uint32_t(p_uchar)); }
};
template <>
struct HashMapHasherDefaultImpl<uint64_t> {
static _FORCE_INLINE_ uint32_t hash(const uint64_t p_int) { return hash_one_uint64(p_int); }
};
template <>
struct HashMapHasherDefaultImpl<int64_t> {
static _FORCE_INLINE_ uint32_t hash(const int64_t p_int) { return hash_one_uint64(uint64_t(p_int)); }
};
template <>
struct HashMapHasherDefaultImpl<float> {
static _FORCE_INLINE_ uint32_t hash(const float p_float) { return hash_murmur3_one_float(p_float); }
};
template <>
struct HashMapHasherDefaultImpl<double> {
static _FORCE_INLINE_ uint32_t hash(const double p_double) { return hash_murmur3_one_double(p_double); }
};
template <>
struct HashMapHasherDefaultImpl<uint32_t> {
static _FORCE_INLINE_ uint32_t hash(const uint32_t p_int) { return hash_fmix32(p_int); }
};
template <>
struct HashMapHasherDefaultImpl<int32_t> {
static _FORCE_INLINE_ uint32_t hash(const int32_t p_int) { return hash_fmix32(uint32_t(p_int)); }
};
template <>
struct HashMapHasherDefaultImpl<uint16_t> {
static _FORCE_INLINE_ uint32_t hash(const uint16_t p_int) { return hash_fmix32(uint32_t(p_int)); }
};
template <>
struct HashMapHasherDefaultImpl<int16_t> {
static _FORCE_INLINE_ uint32_t hash(const int16_t p_int) { return hash_fmix32(uint32_t(p_int)); }
};
template <>
struct HashMapHasherDefaultImpl<uint8_t> {
static _FORCE_INLINE_ uint32_t hash(const uint8_t p_int) { return hash_fmix32(uint32_t(p_int)); }
};
template <>
struct HashMapHasherDefaultImpl<int8_t> {
static _FORCE_INLINE_ uint32_t hash(const int8_t p_int) { return hash_fmix32(uint32_t(p_int)); }
};
template <typename F, typename S>
struct HashMapHasherDefaultImpl<Pair<F, S>> {
static _FORCE_INLINE_ uint32_t hash(const Pair<F, S> &p_pair) {
uint64_t h1 = HashMapHasherDefault::hash(p_pair.first);
uint64_t h2 = HashMapHasherDefault::hash(p_pair.second);
return hash_one_uint64((h1 << 32) | h2);
}
};
template <typename, typename = std::void_t<>>
struct has_is_same_method : std::false_type {};
template <typename T>
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 {};
template <typename T>
constexpr bool has_is_same_method_v = has_is_same_method<T>::value;
struct HashHasher {
static _FORCE_INLINE_ uint32_t hash(const int32_t hash) { return hash; }
static _FORCE_INLINE_ uint32_t hash(const uint32_t hash) { return hash; }
static _FORCE_INLINE_ uint64_t hash(const int64_t hash) { return hash; }
static _FORCE_INLINE_ uint64_t hash(const uint64_t hash) { return hash; }
};
template <typename T, typename = void>
struct HashMapComparatorDefault {
static bool compare(const T &p_lhs, const T &p_rhs) {
return p_lhs == p_rhs;
}
};
template <>
struct HashMapComparatorDefault<float> {
static bool compare(const float &p_lhs, const float &p_rhs) {
return Math::is_same(p_lhs, p_rhs);
}
};
template <>
struct HashMapComparatorDefault<double> {
static bool compare(const double &p_lhs, const double &p_rhs) {
return Math::is_same(p_lhs, p_rhs);
}
};
template <typename T>
struct HashMapComparatorDefault<T, std::enable_if_t<has_is_same_method_v<T>>> {
// For self comparing types.
static bool compare(const T &p_lhs, const T &p_rhs) {
return p_lhs.is_same(p_rhs);
}
};
constexpr uint32_t HASH_TABLE_SIZE_MAX = 29;
inline constexpr uint32_t hash_table_size_primes[HASH_TABLE_SIZE_MAX] = {
5,
13,
23,
47,
97,
193,
389,
769,
1543,
3079,
6151,
12289,
24593,
49157,
98317,
196613,
393241,
786433,
1572869,
3145739,
6291469,
12582917,
25165843,
50331653,
100663319,
201326611,
402653189,
805306457,
1610612741,
};
// 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.
inline constexpr uint64_t hash_table_size_primes_inv[HASH_TABLE_SIZE_MAX] = {
3689348814741910324,
1418980313362273202,
802032351030850071,
392483916461905354,
190172619316593316,
95578984837873325,
47420935922132524,
23987963684927896,
11955116055547344,
5991147799191151,
2998982941588287,
1501077717772769,
750081082979285,
375261795343686,
187625172388393,
93822606204624,
46909513691883,
23456218233098,
11728086747027,
5864041509391,
2932024948977,
1466014921160,
733007198436,
366503839517,
183251896093,
91625960335,
45812983922,
22906489714,
11453246088
};
/**
* Fastmod computes ( n mod d ) given the precomputed c much faster than n % d.
* The implementation of fastmod is based on the following paper by Daniel Lemire et al.
* Faster Remainder by Direct Computation: Applications to Compilers and Software Libraries
* https://arxiv.org/abs/1902.01961
*/
static _FORCE_INLINE_ uint32_t fastmod(const uint32_t n, const uint64_t c, const uint32_t d) {
#if defined(_MSC_VER)
// Returns the upper 64 bits of the product of two 64-bit unsigned integers.
// This intrinsic function is required since MSVC does not support unsigned 128-bit integers.
#if defined(_M_X64) || defined(_M_ARM64)
return __umulh(c * n, d);
#else
// Fallback to the slower method for 32-bit platforms.
return n % d;
#endif // _M_X64 || _M_ARM64
#else
#ifdef __SIZEOF_INT128__
// Prevent compiler warning, because we know what we are doing.
uint64_t lowbits = c * n;
__extension__ typedef unsigned __int128 uint128;
return static_cast<uint64_t>(((uint128)lowbits * d) >> 64);
#else
// Fallback to the slower method if no 128-bit unsigned integer type is available.
return n % d;
#endif // __SIZEOF_INT128__
#endif // _MSC_VER
}