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| 1 // Copyright 2012 Google Inc. All Rights Reserved. | |
| 2 // | |
| 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. | |
| 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 | |
| 18 #include "../webp/types.h" | |
| 19 | |
| 20 #ifdef __cplusplus | |
| 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 int hash_bits_; | |
| 29 } VP8LColorCache; | |
| 30 | |
| 31 static const uint32_t kHashMul = 0x1e35a7bd; | |
| 32 | |
| 33 static WEBP_INLINE uint32_t VP8LColorCacheLookup( | |
| 34 const VP8LColorCache* const cc, uint32_t key) { | |
| 35 assert((key >> cc->hash_bits_) == 0u); | |
| 36 return cc->colors_[key]; | |
| 37 } | |
| 38 | |
| 39 static WEBP_INLINE void VP8LColorCacheSet(const VP8LColorCache* const cc, | |
| 40 uint32_t key, uint32_t argb) { | |
| 41 assert((key >> cc->hash_bits_) == 0u); | |
| 42 cc->colors_[key] = argb; | |
| 43 } | |
| 44 | |
| 45 static WEBP_INLINE void VP8LColorCacheInsert(const VP8LColorCache* const cc, | |
| 46 uint32_t argb) { | |
| 47 const uint32_t key = (kHashMul * argb) >> cc->hash_shift_; | |
| 48 cc->colors_[key] = argb; | |
| 49 } | |
| 50 | |
| 51 static WEBP_INLINE int VP8LColorCacheGetIndex(const VP8LColorCache* const cc, | |
| 52 uint32_t argb) { | |
| 53 return (kHashMul * argb) >> cc->hash_shift_; | |
| 54 } | |
| 55 | |
| 56 static WEBP_INLINE int VP8LColorCacheContains(const VP8LColorCache* const cc, | |
| 57 uint32_t argb) { | |
| 58 const uint32_t key = (kHashMul * argb) >> cc->hash_shift_; | |
| 59 return (cc->colors_[key] == argb); | |
| 60 } | |
| 61 | |
| 62 //------------------------------------------------------------------------------ | |
| 63 | |
| 64 // Initializes the color cache with 'hash_bits' bits for the keys. | |
| 65 // Returns false in case of memory error. | |
| 66 int VP8LColorCacheInit(VP8LColorCache* const color_cache, int hash_bits); | |
| 67 | |
| 68 void VP8LColorCacheCopy(const VP8LColorCache* const src, | |
| 69 VP8LColorCache* const dst); | |
| 70 | |
| 71 // Delete the memory associated to color cache. | |
| 72 void VP8LColorCacheClear(VP8LColorCache* const color_cache); | |
| 73 | |
| 74 //------------------------------------------------------------------------------ | |
| 75 | |
| 76 #ifdef __cplusplus | |
| 77 } | |
| 78 #endif | |
| 79 | |
| 80 #endif // WEBP_UTILS_COLOR_CACHE_H_ | |
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Chromium Code Reviews
Issue 2651883004:
libwebp-0.6.0-rc1 (Closed)
