Vikas Arora | a241572 | 2012-08-09 16:18:58 -0700 | [diff] [blame] | 1 | // Copyright 2012 Google Inc. All Rights Reserved. |
| 2 | // |
Vikas Arora | 0406ce1 | 2013-08-09 15:57:12 -0700 | [diff] [blame] | 3 | // Use of this source code is governed by a BSD-style license |
| 4 | // that can be found in the COPYING file in the root of the source |
| 5 | // tree. An additional intellectual property rights grant can be found |
| 6 | // in the file PATENTS. All contributing project authors may |
| 7 | // be found in the AUTHORS file in the root of the source tree. |
Vikas Arora | a241572 | 2012-08-09 16:18:58 -0700 | [diff] [blame] | 8 | // ----------------------------------------------------------------------------- |
| 9 | // |
| 10 | // Color Cache for WebP Lossless |
| 11 | // |
| 12 | // Authors: Jyrki Alakuijala (jyrki@google.com) |
| 13 | // Urvang Joshi (urvang@google.com) |
| 14 | |
| 15 | #ifndef WEBP_UTILS_COLOR_CACHE_H_ |
| 16 | #define WEBP_UTILS_COLOR_CACHE_H_ |
| 17 | |
James Zern | 9e80ee9 | 2015-03-17 18:54:21 -0700 | [diff] [blame] | 18 | #include "../webp/types.h" |
Vikas Arora | a241572 | 2012-08-09 16:18:58 -0700 | [diff] [blame] | 19 | |
Vikas Arora | 8b72022 | 2014-01-02 16:48:02 -0800 | [diff] [blame] | 20 | #ifdef __cplusplus |
Vikas Arora | a241572 | 2012-08-09 16:18:58 -0700 | [diff] [blame] | 21 | extern "C" { |
| 22 | #endif |
| 23 | |
| 24 | // Main color cache struct. |
| 25 | typedef struct { |
| 26 | uint32_t *colors_; // color entries |
| 27 | int hash_shift_; // Hash shift: 32 - hash_bits. |
| 28 | } VP8LColorCache; |
| 29 | |
| 30 | static const uint32_t kHashMul = 0x1e35a7bd; |
| 31 | |
| 32 | static WEBP_INLINE uint32_t VP8LColorCacheLookup( |
| 33 | const VP8LColorCache* const cc, uint32_t key) { |
| 34 | assert(key <= (~0U >> cc->hash_shift_)); |
| 35 | return cc->colors_[key]; |
| 36 | } |
| 37 | |
| 38 | static WEBP_INLINE void VP8LColorCacheInsert(const VP8LColorCache* const cc, |
| 39 | uint32_t argb) { |
| 40 | const uint32_t key = (kHashMul * argb) >> cc->hash_shift_; |
| 41 | cc->colors_[key] = argb; |
| 42 | } |
| 43 | |
| 44 | static WEBP_INLINE int VP8LColorCacheGetIndex(const VP8LColorCache* const cc, |
| 45 | uint32_t argb) { |
| 46 | return (kHashMul * argb) >> cc->hash_shift_; |
| 47 | } |
| 48 | |
| 49 | static WEBP_INLINE int VP8LColorCacheContains(const VP8LColorCache* const cc, |
| 50 | uint32_t argb) { |
| 51 | const uint32_t key = (kHashMul * argb) >> cc->hash_shift_; |
| 52 | return cc->colors_[key] == argb; |
| 53 | } |
| 54 | |
| 55 | //------------------------------------------------------------------------------ |
| 56 | |
| 57 | // Initializes the color cache with 'hash_bits' bits for the keys. |
| 58 | // Returns false in case of memory error. |
| 59 | int VP8LColorCacheInit(VP8LColorCache* const color_cache, int hash_bits); |
| 60 | |
| 61 | // Delete the memory associated to color cache. |
| 62 | void VP8LColorCacheClear(VP8LColorCache* const color_cache); |
| 63 | |
| 64 | //------------------------------------------------------------------------------ |
| 65 | |
Vikas Arora | 8b72022 | 2014-01-02 16:48:02 -0800 | [diff] [blame] | 66 | #ifdef __cplusplus |
Vikas Arora | a241572 | 2012-08-09 16:18:58 -0700 | [diff] [blame] | 67 | } |
| 68 | #endif |
| 69 | |
| 70 | #endif // WEBP_UTILS_COLOR_CACHE_H_ |