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// 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_