godot/core/hashfuncs.h
2017-09-19 16:48:53 +02:00

166 lines
5.7 KiB
C++

/*************************************************************************/
/* hashfuncs.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2017 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 "math_defs.h"
#include "math_funcs.h"
#include "typedefs.h"
#include "ustring.h"
/**
* Hashing functions
*/
/**
* DJB2 Hash function
* @param C String
* @return 32-bits hashcode
*/
static 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 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 inline uint32_t hash_djb2_one_32(uint32_t p_in, uint32_t p_prev = 5381) {
return ((p_prev << 5) + p_prev) + p_in;
}
static 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 (int)v;
}
static 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 = Math_NAN;
else
u.d = p_in;
return ((p_prev << 5) + p_prev) + hash_one_uint64(u.i);
}
template <class T>
static 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 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 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;
}
struct HashMapHasherDefault {
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 uint64_t p_int) { return hash_one_uint64(p_int); }
static _FORCE_INLINE_ uint32_t hash(const int64_t p_int) { return hash(uint64_t(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 p_int; }
static _FORCE_INLINE_ uint32_t hash(const int32_t p_int) { return (uint32_t)p_int; }
static _FORCE_INLINE_ uint32_t hash(const uint16_t p_int) { return p_int; }
static _FORCE_INLINE_ uint32_t hash(const int16_t p_int) { return (uint32_t)p_int; }
static _FORCE_INLINE_ uint32_t hash(const uint8_t p_int) { return p_int; }
static _FORCE_INLINE_ uint32_t hash(const int8_t p_int) { return (uint32_t)p_int; }
static _FORCE_INLINE_ uint32_t hash(const wchar_t p_wchar) { return (uint32_t)p_wchar; }
//static _FORCE_INLINE_ uint32_t hash(const void* p_ptr) { return uint32_t(uint64_t(p_ptr))*(0x9e3779b1L); }
};
template <typename T>
struct HashMapComparatorDefault {
static bool compare(const T &p_lhs, const T &p_rhs) {
return p_lhs == p_rhs;
}
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));
}
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));
}
};
#endif