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-rw-r--r--media/libwebp/src/utils/color_cache_utils.h89
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
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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_