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Diffstat (limited to 'src/3rdparty/libwebp/src/enc/backward_references.h')
-rw-r--r-- | src/3rdparty/libwebp/src/enc/backward_references.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/enc/backward_references.h b/src/3rdparty/libwebp/src/enc/backward_references.h new file mode 100644 index 0000000..e1c75f0 --- /dev/null +++ b/src/3rdparty/libwebp/src/enc/backward_references.h @@ -0,0 +1,152 @@ +// 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. +// ----------------------------------------------------------------------------- +// +// Author: Jyrki Alakuijala (jyrki@google.com) +// + +#ifndef WEBP_ENC_BACKWARD_REFERENCES_H_ +#define WEBP_ENC_BACKWARD_REFERENCES_H_ + +#include <assert.h> +#include <stdlib.h> +#include "../webp/types.h" +#include "../webp/format_constants.h" + +#ifdef __cplusplus +extern "C" { +#endif + +// The spec allows 11, we use 9 bits to reduce memory consumption in encoding. +// Having 9 instead of 11 only removes about 0.25 % of compression density. +#define MAX_COLOR_CACHE_BITS 9 + +// Max ever number of codes we'll use: +#define PIX_OR_COPY_CODES_MAX \ + (NUM_LITERAL_CODES + NUM_LENGTH_CODES + (1 << MAX_COLOR_CACHE_BITS)) + +// ----------------------------------------------------------------------------- +// PixOrCopy + +enum Mode { + kLiteral, + kCacheIdx, + kCopy, + kNone +}; + +typedef struct { + // mode as uint8_t to make the memory layout to be exactly 8 bytes. + uint8_t mode; + uint16_t len; + uint32_t argb_or_distance; +} PixOrCopy; + +static WEBP_INLINE PixOrCopy PixOrCopyCreateCopy(uint32_t distance, + uint16_t len) { + PixOrCopy retval; + retval.mode = kCopy; + retval.argb_or_distance = distance; + retval.len = len; + return retval; +} + +static WEBP_INLINE PixOrCopy PixOrCopyCreateCacheIdx(int idx) { + PixOrCopy retval; + assert(idx >= 0); + assert(idx < (1 << MAX_COLOR_CACHE_BITS)); + retval.mode = kCacheIdx; + retval.argb_or_distance = idx; + retval.len = 1; + return retval; +} + +static WEBP_INLINE PixOrCopy PixOrCopyCreateLiteral(uint32_t argb) { + PixOrCopy retval; + retval.mode = kLiteral; + retval.argb_or_distance = argb; + retval.len = 1; + return retval; +} + +static WEBP_INLINE int PixOrCopyIsLiteral(const PixOrCopy* const p) { + return (p->mode == kLiteral); +} + +static WEBP_INLINE int PixOrCopyIsCacheIdx(const PixOrCopy* const p) { + return (p->mode == kCacheIdx); +} + +static WEBP_INLINE int PixOrCopyIsCopy(const PixOrCopy* const p) { + return (p->mode == kCopy); +} + +static WEBP_INLINE uint32_t PixOrCopyLiteral(const PixOrCopy* const p, + int component) { + assert(p->mode == kLiteral); + return (p->argb_or_distance >> (component * 8)) & 0xff; +} + +static WEBP_INLINE uint32_t PixOrCopyLength(const PixOrCopy* const p) { + return p->len; +} + +static WEBP_INLINE uint32_t PixOrCopyArgb(const PixOrCopy* const p) { + assert(p->mode == kLiteral); + return p->argb_or_distance; +} + +static WEBP_INLINE uint32_t PixOrCopyCacheIdx(const PixOrCopy* const p) { + assert(p->mode == kCacheIdx); + assert(p->argb_or_distance < (1U << MAX_COLOR_CACHE_BITS)); + return p->argb_or_distance; +} + +static WEBP_INLINE uint32_t PixOrCopyDistance(const PixOrCopy* const p) { + assert(p->mode == kCopy); + return p->argb_or_distance; +} + +// ----------------------------------------------------------------------------- +// VP8LBackwardRefs + +typedef struct { + PixOrCopy* refs; + int size; // currently used + int max_size; // maximum capacity +} VP8LBackwardRefs; + +// Initialize the object. Must be called first. 'refs' can be NULL. +void VP8LInitBackwardRefs(VP8LBackwardRefs* const refs); + +// Release memory and re-initialize the object. 'refs' can be NULL. +void VP8LClearBackwardRefs(VP8LBackwardRefs* const refs); + +// Allocate 'max_size' references. Returns false in case of memory error. +int VP8LBackwardRefsAlloc(VP8LBackwardRefs* const refs, int max_size); + +// ----------------------------------------------------------------------------- +// Main entry points + +// Evaluates best possible backward references for specified quality. +// Further optimize for 2D locality if use_2d_locality flag is set. +int VP8LGetBackwardReferences(int width, int height, + const uint32_t* const argb, + int quality, int cache_bits, int use_2d_locality, + VP8LBackwardRefs* const best); + +// Produce an estimate for a good color cache size for the image. +int VP8LCalculateEstimateForCacheSize(const uint32_t* const argb, + int xsize, int ysize, + int* const best_cache_bits); + +#ifdef __cplusplus +} +#endif + +#endif // WEBP_ENC_BACKWARD_REFERENCES_H_ |