virtualx-engine/core/templates/hashfuncs.h
2022-06-15 00:32:10 +02:00

340 lines
11 KiB
C++

/*************************************************************************/
/* hashfuncs.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 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 HASHFUNCS_H
#define HASHFUNCS_H
#include "core/math/aabb.h"
#include "core/math/math_defs.h"
#include "core/math/math_funcs.h"
#include "core/math/rect2.h"
#include "core/math/rect2i.h"
#include "core/math/vector2.h"
#include "core/math/vector2i.h"
#include "core/math/vector3.h"
#include "core/math/vector3i.h"
#include "core/object/object_id.h"
#include "core/string/node_path.h"
#include "core/string/string_name.h"
#include "core/string/ustring.h"
#include "core/templates/rid.h"
#include "core/typedefs.h"
/**
* Hashing functions
*/
/**
* DJB2 Hash function
* @param C String
* @return 32-bits hashcode
*/
static _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;
while ((c = *chr++)) {
hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
}
return hash;
}
static _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;
}
static _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
*/
static _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);
}
// Murmurhash3 32-bit version.
// All MurmurHash versions are public domain software, and the author disclaims all copyright to their code.
static _FORCE_INLINE_ uint32_t rotl32(uint32_t x, int8_t r) {
return (x << r) | (x >> (32 - r));
}
static _FORCE_INLINE_ uint32_t fmix32(uint32_t h) {
h ^= h >> 16;
h *= 0x85ebca6b;
h ^= h >> 13;
h *= 0xc2b2ae35;
h ^= h >> 16;
return h;
}
static _FORCE_INLINE_ uint32_t hash_murmur3_32(const void *key, int length, const uint32_t seed = 0x7F07C65) {
// Although not required, this is a random prime number.
const uint8_t *data = (const uint8_t *)key;
const int nblocks = length / 4;
uint32_t h1 = seed;
const uint32_t c1 = 0xcc9e2d51;
const uint32_t c2 = 0x1b873593;
const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
for (int i = -nblocks; i; i++) {
uint32_t k1 = blocks[i];
k1 *= c1;
k1 = rotl32(k1, 15);
k1 *= c2;
h1 ^= k1;
h1 = rotl32(h1, 13);
h1 = h1 * 5 + 0xe6546b64;
}
const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
uint32_t k1 = 0;
switch (length & 3) {
case 3:
k1 ^= tail[2] << 16;
[[fallthrough]];
case 2:
k1 ^= tail[1] << 8;
[[fallthrough]];
case 1:
k1 ^= tail[0];
k1 *= c1;
k1 = rotl32(k1, 15);
k1 *= c2;
h1 ^= k1;
};
// Finalize with additional bit mixing.
h1 ^= length;
return fmix32(h1);
}
static _FORCE_INLINE_ uint32_t hash_djb2_one_float(double p_in, uint32_t p_prev = 5381) {
union {
double d;
uint64_t i;
} u;
// Normalize +/- 0.0 and NaN values so they hash the same.
if (p_in == 0.0f) {
u.d = 0.0;
} else if (Math::is_nan(p_in)) {
u.d = NAN;
} else {
u.d = p_in;
}
return ((p_prev << 5) + p_prev) + hash_one_uint64(u.i);
}
template <class T>
static _FORCE_INLINE_ uint32_t make_uint32_t(T p_in) {
union {
T t;
uint32_t _u32;
} _u;
_u._u32 = 0;
_u.t = p_in;
return _u._u32;
}
static _FORCE_INLINE_ uint64_t hash_djb2_one_float_64(double p_in, uint64_t p_prev = 5381) {
union {
double d;
uint64_t i;
} u;
// Normalize +/- 0.0 and NaN values so they hash the same.
if (p_in == 0.0f) {
u.d = 0.0;
} else if (Math::is_nan(p_in)) {
u.d = NAN;
} else {
u.d = p_in;
}
return ((p_prev << 5) + p_prev) + u.i;
}
static _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 <class T>
static _FORCE_INLINE_ uint64_t make_uint64_t(T p_in) {
union {
T t;
uint64_t _u64;
} _u;
_u._u64 = 0; // in case p_in is smaller
_u.t = p_in;
return _u._u64;
}
template <class T>
class Ref;
struct HashMapHasherDefault {
// Generic hash function for any type.
template <class T>
static _FORCE_INLINE_ uint32_t hash(const T *p_pointer) { return hash_one_uint64((uint64_t)p_pointer); }
template <class T>
static _FORCE_INLINE_ uint32_t hash(const Ref<T> &p_ref) { return hash_one_uint64((uint64_t)p_ref.operator->()); }
static _FORCE_INLINE_ uint32_t hash(const String &p_string) { return p_string.hash(); }
static _FORCE_INLINE_ uint32_t hash(const char *p_cstr) { return hash_djb2(p_cstr); }
static _FORCE_INLINE_ uint32_t hash(const wchar_t p_wchar) { return fmix32(p_wchar); }
static _FORCE_INLINE_ uint32_t hash(const char16_t p_uchar) { return fmix32(p_uchar); }
static _FORCE_INLINE_ uint32_t hash(const char32_t p_uchar) { return fmix32(p_uchar); }
static _FORCE_INLINE_ uint32_t hash(const RID &p_rid) { return hash_one_uint64(p_rid.get_id()); }
static _FORCE_INLINE_ uint32_t hash(const StringName &p_string_name) { return p_string_name.hash(); }
static _FORCE_INLINE_ uint32_t hash(const NodePath &p_path) { return p_path.hash(); }
static _FORCE_INLINE_ uint32_t hash(const ObjectID &p_id) { return hash_one_uint64(p_id); }
static _FORCE_INLINE_ uint32_t hash(const uint64_t p_int) { return hash_one_uint64(p_int); }
static _FORCE_INLINE_ uint32_t hash(const int64_t p_int) { return hash_one_uint64(p_int); }
static _FORCE_INLINE_ uint32_t hash(const float p_float) { return hash_djb2_one_float(p_float); }
static _FORCE_INLINE_ uint32_t hash(const double p_double) { return hash_djb2_one_float(p_double); }
static _FORCE_INLINE_ uint32_t hash(const uint32_t p_int) { return fmix32(p_int); }
static _FORCE_INLINE_ uint32_t hash(const int32_t p_int) { return fmix32(p_int); }
static _FORCE_INLINE_ uint32_t hash(const uint16_t p_int) { return fmix32(p_int); }
static _FORCE_INLINE_ uint32_t hash(const int16_t p_int) { return fmix32(p_int); }
static _FORCE_INLINE_ uint32_t hash(const uint8_t p_int) { return fmix32(p_int); }
static _FORCE_INLINE_ uint32_t hash(const int8_t p_int) { return fmix32(p_int); }
static _FORCE_INLINE_ uint32_t hash(const Vector2i &p_vec) { return hash_murmur3_32(&p_vec, sizeof(Vector2i)); }
static _FORCE_INLINE_ uint32_t hash(const Vector3i &p_vec) { return hash_murmur3_32(&p_vec, sizeof(Vector3i)); }
static _FORCE_INLINE_ uint32_t hash(const Vector2 &p_vec) { return hash_murmur3_32(&p_vec, sizeof(Vector2)); }
static _FORCE_INLINE_ uint32_t hash(const Vector3 &p_vec) { return hash_murmur3_32(&p_vec, sizeof(Vector3)); }
static _FORCE_INLINE_ uint32_t hash(const Rect2i &p_rect) { return hash_murmur3_32(&p_rect, sizeof(Rect2i)); }
static _FORCE_INLINE_ uint32_t hash(const Rect2 &p_rect) { return hash_murmur3_32(&p_rect, sizeof(Rect2)); }
static _FORCE_INLINE_ uint32_t hash(const AABB &p_aabb) { return hash_murmur3_32(&p_aabb, sizeof(AABB)); }
};
template <typename T>
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 (p_lhs == p_rhs) || (Math::is_nan(p_lhs) && Math::is_nan(p_rhs));
}
};
template <>
struct HashMapComparatorDefault<double> {
static bool compare(const double &p_lhs, const double &p_rhs) {
return (p_lhs == p_rhs) || (Math::is_nan(p_lhs) && Math::is_nan(p_rhs));
}
};
template <>
struct HashMapComparatorDefault<Vector2> {
static bool compare(const Vector2 &p_lhs, const Vector2 &p_rhs) {
return ((p_lhs.x == p_rhs.x) || (Math::is_nan(p_lhs.x) && Math::is_nan(p_rhs.x))) && ((p_lhs.y == p_rhs.y) || (Math::is_nan(p_lhs.y) && Math::is_nan(p_rhs.y)));
}
};
template <>
struct HashMapComparatorDefault<Vector3> {
static bool compare(const Vector3 &p_lhs, const Vector3 &p_rhs) {
return ((p_lhs.x == p_rhs.x) || (Math::is_nan(p_lhs.x) && Math::is_nan(p_rhs.x))) && ((p_lhs.y == p_rhs.y) || (Math::is_nan(p_lhs.y) && Math::is_nan(p_rhs.y))) && ((p_lhs.z == p_rhs.z) || (Math::is_nan(p_lhs.z) && Math::is_nan(p_rhs.z)));
}
};
constexpr uint32_t HASH_TABLE_SIZE_MAX = 29;
const 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,
};
#endif // HASHFUNCS_H