diff options
Diffstat (limited to 'media/libwebp/src/utils/color_cache_utils.h')
-rw-r--r-- | media/libwebp/src/utils/color_cache_utils.h | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/media/libwebp/src/utils/color_cache_utils.h b/media/libwebp/src/utils/color_cache_utils.h new file mode 100644 index 0000000000..b45d47c2d5 --- /dev/null +++ b/media/libwebp/src/utils/color_cache_utils.h @@ -0,0 +1,89 @@ +// Copyright 2012 Google Inc. All Rights Reserved. +// +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. +// ----------------------------------------------------------------------------- +// +// Color Cache for WebP Lossless +// +// Authors: Jyrki Alakuijala (jyrki@google.com) +// Urvang Joshi (urvang@google.com) + +#ifndef WEBP_UTILS_COLOR_CACHE_UTILS_H_ +#define WEBP_UTILS_COLOR_CACHE_UTILS_H_ + +#include <assert.h> + +#include "src/dsp/dsp.h" +#include "src/webp/types.h" + +#ifdef __cplusplus +extern "C" { +#endif + +// Main color cache struct. +typedef struct { + uint32_t* colors_; // color entries + int hash_shift_; // Hash shift: 32 - hash_bits_. + int hash_bits_; +} VP8LColorCache; + +static const uint32_t kHashMul = 0x1e35a7bdu; + +static WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW WEBP_INLINE +int VP8LHashPix(uint32_t argb, int shift) { + return (int)((argb * kHashMul) >> shift); +} + +static WEBP_INLINE uint32_t VP8LColorCacheLookup( + const VP8LColorCache* const cc, uint32_t key) { + assert((key >> cc->hash_bits_) == 0u); + return cc->colors_[key]; +} + +static WEBP_INLINE void VP8LColorCacheSet(const VP8LColorCache* const cc, + uint32_t key, uint32_t argb) { + assert((key >> cc->hash_bits_) == 0u); + cc->colors_[key] = argb; +} + +static WEBP_INLINE void VP8LColorCacheInsert(const VP8LColorCache* const cc, + uint32_t argb) { + const int key = VP8LHashPix(argb, cc->hash_shift_); + cc->colors_[key] = argb; +} + +static WEBP_INLINE int VP8LColorCacheGetIndex(const VP8LColorCache* const cc, + uint32_t argb) { + return VP8LHashPix(argb, cc->hash_shift_); +} + +// Return the key if cc contains argb, and -1 otherwise. +static WEBP_INLINE int VP8LColorCacheContains(const VP8LColorCache* const cc, + uint32_t argb) { + const int key = VP8LHashPix(argb, cc->hash_shift_); + return (cc->colors_[key] == argb) ? key : -1; +} + +//------------------------------------------------------------------------------ + +// Initializes the color cache with 'hash_bits' bits for the keys. +// Returns false in case of memory error. +int VP8LColorCacheInit(VP8LColorCache* const color_cache, int hash_bits); + +void VP8LColorCacheCopy(const VP8LColorCache* const src, + VP8LColorCache* const dst); + +// Delete the memory associated to color cache. +void VP8LColorCacheClear(VP8LColorCache* const color_cache); + +//------------------------------------------------------------------------------ + +#ifdef __cplusplus +} +#endif + +#endif // WEBP_UTILS_COLOR_CACHE_UTILS_H_ |