83 lines
2.5 KiB
C
83 lines
2.5 KiB
C
/*
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* Cogl
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*
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* A Low Level GPU Graphics and Utilities API
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*
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* Copyright (C) 2007,2008,2009,2010 Intel Corporation.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to 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
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*
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*/
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#pragma once
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#include <glib.h>
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#include <math.h>
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#include "cogl/cogl-pixel-format.h"
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#include "cogl/cogl-types.h"
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#include <stdio.h>
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/* This is a replacement for the nearbyint function which always
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rounds to the nearest integer. nearbyint is apparently a C99
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function so it might not always be available but also it seems in
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glibc it is defined as a function call so this macro could end up
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faster anyway. We can't just add 0.5f because it will break for
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negative numbers. */
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#define COGL_UTIL_NEARBYINT(x) ((int) ((x) < 0.0f ? (x) - 0.5f : (x) + 0.5f))
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/* Split Bob Jenkins' One-at-a-Time hash
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*
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* This uses the One-at-a-Time hash algorithm designed by Bob Jenkins
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* but the mixing step is split out so the function can be used in a
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* more incremental fashion.
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*/
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static inline unsigned int
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_cogl_util_one_at_a_time_hash (unsigned int hash,
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const void *key,
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size_t bytes)
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{
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const unsigned char *p = key;
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size_t i;
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for (i = 0; i < bytes; i++)
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{
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hash += p[i];
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hash += (hash << 10);
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hash ^= (hash >> 6);
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}
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return hash;
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}
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static inline unsigned int
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_cogl_util_one_at_a_time_mix (unsigned int hash)
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{
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hash += ( hash << 3 );
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hash ^= ( hash >> 11 );
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hash += ( hash << 15 );
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return hash;
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}
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