154 lines
4.2 KiB
C++
154 lines
4.2 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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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2017 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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#ifndef HASHFUNCS_H
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#define HASHFUNCS_H
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#include "math_funcs.h"
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#include "math_defs.h"
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#include "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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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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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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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 (int) v;
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}
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static inline uint32_t hash_djb2_one_float(float p_in,uint32_t p_prev=5381) {
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union {
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float f;
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uint32_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.f=0.0;
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else if (Math::is_nan(p_in))
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u.f=Math_NAN;
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else
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u.f=p_in;
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return ((p_prev<<5)+p_prev)+u.i;
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}
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// Overload for real_t size changes
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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=Math_NAN;
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else
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u.d=p_in;
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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_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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#endif
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