color_cache_utils.c

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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

//

// Author: Jyrki Alakuijala (jyrki@google.com)

#include <assert.h>

#include <stdlib.h>

#include <string.h>

#include "src/utils/color_cache_utils.h"

#include "src/utils/utils.h"

//------------------------------------------------------------------------------

// VP8LColorCache.

int VP8LColorCacheInit(VP8LColorCache* const color_cache, int hash_bits) {

  const int hash_size = 1 << hash_bits;

  assert(color_cache != NULL);

  assert(hash_bits > 0);

  color_cache->colors_ = (uint32_t*)WebPSafeCalloc(

      (uint64_t)hash_size, sizeof(*color_cache->colors_));

  if (color_cache->colors_ == NULL) return 0;

  color_cache->hash_shift_ = 32 - hash_bits;

  color_cache->hash_bits_ = hash_bits;

  return 1;

void VP8LColorCacheClear(VP8LColorCache* const color_cache) {

  if (color_cache != NULL) {

    WebPSafeFree(color_cache->colors_);

    color_cache->colors_ = NULL;

void VP8LColorCacheCopy(const VP8LColorCache* const src,

                        VP8LColorCache* const dst) {

  assert(src != NULL);

  assert(dst != NULL);

  assert(src->hash_bits_ == dst->hash_bits_);

  memcpy(dst->colors_, src->colors_,

         ((size_t)1u << dst->hash_bits_) * sizeof(*dst->colors_));