152 lines
4.5 KiB
C
152 lines
4.5 KiB
C
// 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_
|