/usr/include/guacamole/hash.h is in libguac-dev 0.9.9-2build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | /*
* Copyright (C) 2013 Glyptodon LLC
*
* 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 _GUAC_HASH_H
#define _GUAC_HASH_H
/**
* Provides functions and structures for producing likely-to-be-unique hash
* values for images.
*
* @file hash.h
*/
#include <cairo/cairo.h>
/**
* Produces a 24-bit hash value from all pixels of the given surface. The
* surface provided must be RGB or ARGB with each pixel stored in 32 bits.
* The hashing algorithm used is a variant of the cyclic polynomial rolling
* hash.
*
* @param surface The Cairo surface to hash.
* @return An arbitrary 24-bit unsigned integer value intended to be well
* distributed across different images.
*/
unsigned int guac_hash_surface(cairo_surface_t* surface);
/**
* Given two Cairo surfaces, returns zero if the data contained within each
* is identical, and a positive or negative value if the value of the first
* is found to be lexically greater or less than the second respectively.
*
* @param a The first Cairo surface to compare.
* @param b The Cairo surface to compare the first surface against.
* @return Zero if the data contained within each is identical, and a positive
* or negative value if the value of the first is found to be lexically
* greater or less than the second respectively.
*/
int guac_surface_cmp(cairo_surface_t* a, cairo_surface_t* b);
#endif
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