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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.
- // -----------------------------------------------------------------------------
- //
- // Image transforms and color space conversion methods for lossless decoder.
- //
- // Authors: Vikas Arora (vikaas.arora@gmail.com)
- // Jyrki Alakuijala (jyrki@google.com)
- #ifndef WEBP_DSP_LOSSLESS_H_
- #define WEBP_DSP_LOSSLESS_H_
- #include "../webp/types.h"
- #include "../webp/decode.h"
- #include "../enc/histogram.h"
- #include "../utils/utils.h"
- #ifdef __cplusplus
- extern "C" {
- #endif
- //------------------------------------------------------------------------------
- // Signatures and generic function-pointers
- typedef uint32_t (*VP8LPredictorFunc)(uint32_t left, const uint32_t* const top);
- extern VP8LPredictorFunc VP8LPredictors[16];
- typedef void (*VP8LProcessBlueAndRedFunc)(uint32_t* argb_data, int num_pixels);
- extern VP8LProcessBlueAndRedFunc VP8LSubtractGreenFromBlueAndRed;
- extern VP8LProcessBlueAndRedFunc VP8LAddGreenToBlueAndRed;
- typedef struct {
- // Note: the members are uint8_t, so that any negative values are
- // automatically converted to "mod 256" values.
- uint8_t green_to_red_;
- uint8_t green_to_blue_;
- uint8_t red_to_blue_;
- } VP8LMultipliers;
- typedef void (*VP8LTransformColorFunc)(const VP8LMultipliers* const m,
- uint32_t* argb_data, int num_pixels);
- extern VP8LTransformColorFunc VP8LTransformColor;
- extern VP8LTransformColorFunc VP8LTransformColorInverse;
- typedef void (*VP8LConvertFunc)(const uint32_t* src, int num_pixels,
- uint8_t* dst);
- extern VP8LConvertFunc VP8LConvertBGRAToRGB;
- extern VP8LConvertFunc VP8LConvertBGRAToRGBA;
- extern VP8LConvertFunc VP8LConvertBGRAToRGBA4444;
- extern VP8LConvertFunc VP8LConvertBGRAToRGB565;
- extern VP8LConvertFunc VP8LConvertBGRAToBGR;
- // Expose some C-only fallback functions
- void VP8LTransformColor_C(const VP8LMultipliers* const m,
- uint32_t* data, int num_pixels);
- void VP8LTransformColorInverse_C(const VP8LMultipliers* const m,
- uint32_t* data, int num_pixels);
- void VP8LConvertBGRAToRGB_C(const uint32_t* src, int num_pixels, uint8_t* dst);
- void VP8LConvertBGRAToRGBA_C(const uint32_t* src, int num_pixels, uint8_t* dst);
- void VP8LConvertBGRAToRGBA4444_C(const uint32_t* src,
- int num_pixels, uint8_t* dst);
- void VP8LConvertBGRAToRGB565_C(const uint32_t* src,
- int num_pixels, uint8_t* dst);
- void VP8LConvertBGRAToBGR_C(const uint32_t* src, int num_pixels, uint8_t* dst);
- void VP8LSubtractGreenFromBlueAndRed_C(uint32_t* argb_data, int num_pixels);
- void VP8LAddGreenToBlueAndRed_C(uint32_t* data, int num_pixels);
- // Must be called before calling any of the above methods.
- void VP8LDspInit(void);
- //------------------------------------------------------------------------------
- // Image transforms.
- struct VP8LTransform; // Defined in dec/vp8li.h.
- // Performs inverse transform of data given transform information, start and end
- // rows. Transform will be applied to rows [row_start, row_end[.
- // The *in and *out pointers refer to source and destination data respectively
- // corresponding to the intermediate row (row_start).
- void VP8LInverseTransform(const struct VP8LTransform* const transform,
- int row_start, int row_end,
- const uint32_t* const in, uint32_t* const out);
- // Similar to the static method ColorIndexInverseTransform() that is part of
- // lossless.c, but used only for alpha decoding. It takes uint8_t (rather than
- // uint32_t) arguments for 'src' and 'dst'.
- void VP8LColorIndexInverseTransformAlpha(
- const struct VP8LTransform* const transform, int y_start, int y_end,
- const uint8_t* src, uint8_t* dst);
- void VP8LResidualImage(int width, int height, int bits,
- uint32_t* const argb, uint32_t* const argb_scratch,
- uint32_t* const image);
- void VP8LColorSpaceTransform(int width, int height, int bits, int quality,
- uint32_t* const argb, uint32_t* image);
- //------------------------------------------------------------------------------
- // Color space conversion.
- // Converts from BGRA to other color spaces.
- void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels,
- WEBP_CSP_MODE out_colorspace, uint8_t* const rgba);
- //------------------------------------------------------------------------------
- // Misc methods.
- // Computes sampled size of 'size' when sampling using 'sampling bits'.
- static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size,
- uint32_t sampling_bits) {
- return (size + (1 << sampling_bits) - 1) >> sampling_bits;
- }
- // -----------------------------------------------------------------------------
- // Faster logarithm for integers. Small values use a look-up table.
- #define LOG_LOOKUP_IDX_MAX 256
- extern const float kLog2Table[LOG_LOOKUP_IDX_MAX];
- extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX];
- typedef float (*VP8LFastLog2SlowFunc)(uint32_t v);
- extern VP8LFastLog2SlowFunc VP8LFastLog2Slow;
- extern VP8LFastLog2SlowFunc VP8LFastSLog2Slow;
- static WEBP_INLINE float VP8LFastLog2(uint32_t v) {
- return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v);
- }
- // Fast calculation of v * log2(v) for integer input.
- static WEBP_INLINE float VP8LFastSLog2(uint32_t v) {
- return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v);
- }
- // -----------------------------------------------------------------------------
- // Huffman-cost related functions.
- typedef double (*VP8LCostFunc)(const uint32_t* population, int length);
- typedef double (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y,
- int length);
- extern VP8LCostFunc VP8LExtraCost;
- extern VP8LCostCombinedFunc VP8LExtraCostCombined;
- typedef struct { // small struct to hold counters
- int counts[2]; // index: 0=zero steak, 1=non-zero streak
- int streaks[2][2]; // [zero/non-zero][streak<3 / streak>=3]
- } VP8LStreaks;
- typedef VP8LStreaks (*VP8LCostCountFunc)(const uint32_t* population,
- int length);
- typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X,
- const uint32_t* Y, int length);
- extern VP8LCostCountFunc VP8LHuffmanCostCount;
- extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
- typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a,
- const VP8LHistogram* const b,
- VP8LHistogram* const out);
- extern VP8LHistogramAddFunc VP8LHistogramAdd;
- // -----------------------------------------------------------------------------
- // PrefixEncode()
- static WEBP_INLINE int VP8LBitsLog2Ceiling(uint32_t n) {
- const int log_floor = BitsLog2Floor(n);
- if (n == (n & ~(n - 1))) // zero or a power of two.
- return log_floor;
- else
- return log_floor + 1;
- }
- // Splitting of distance and length codes into prefixes and
- // extra bits. The prefixes are encoded with an entropy code
- // while the extra bits are stored just as normal bits.
- static WEBP_INLINE void VP8LPrefixEncodeBitsNoLUT(int distance, int* const code,
- int* const extra_bits) {
- const int highest_bit = BitsLog2Floor(--distance);
- const int second_highest_bit = (distance >> (highest_bit - 1)) & 1;
- *extra_bits = highest_bit - 1;
- *code = 2 * highest_bit + second_highest_bit;
- }
- static WEBP_INLINE void VP8LPrefixEncodeNoLUT(int distance, int* const code,
- int* const extra_bits,
- int* const extra_bits_value) {
- const int highest_bit = BitsLog2Floor(--distance);
- const int second_highest_bit = (distance >> (highest_bit - 1)) & 1;
- *extra_bits = highest_bit - 1;
- *extra_bits_value = distance & ((1 << *extra_bits) - 1);
- *code = 2 * highest_bit + second_highest_bit;
- }
- #define PREFIX_LOOKUP_IDX_MAX 512
- typedef struct {
- int8_t code_;
- int8_t extra_bits_;
- } VP8LPrefixCode;
- // These tables are derived using VP8LPrefixEncodeNoLUT.
- extern const VP8LPrefixCode kPrefixEncodeCode[PREFIX_LOOKUP_IDX_MAX];
- extern const uint8_t kPrefixEncodeExtraBitsValue[PREFIX_LOOKUP_IDX_MAX];
- static WEBP_INLINE void VP8LPrefixEncodeBits(int distance, int* const code,
- int* const extra_bits) {
- if (distance < PREFIX_LOOKUP_IDX_MAX) {
- const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance];
- *code = prefix_code.code_;
- *extra_bits = prefix_code.extra_bits_;
- } else {
- VP8LPrefixEncodeBitsNoLUT(distance, code, extra_bits);
- }
- }
- static WEBP_INLINE void VP8LPrefixEncode(int distance, int* const code,
- int* const extra_bits,
- int* const extra_bits_value) {
- if (distance < PREFIX_LOOKUP_IDX_MAX) {
- const VP8LPrefixCode prefix_code = kPrefixEncodeCode[distance];
- *code = prefix_code.code_;
- *extra_bits = prefix_code.extra_bits_;
- *extra_bits_value = kPrefixEncodeExtraBitsValue[distance];
- } else {
- VP8LPrefixEncodeNoLUT(distance, code, extra_bits, extra_bits_value);
- }
- }
- // In-place difference of each component with mod 256.
- static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) {
- const uint32_t alpha_and_green =
- 0x00ff00ffu + (a & 0xff00ff00u) - (b & 0xff00ff00u);
- const uint32_t red_and_blue =
- 0xff00ff00u + (a & 0x00ff00ffu) - (b & 0x00ff00ffu);
- return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu);
- }
- void VP8LBundleColorMap(const uint8_t* const row, int width,
- int xbits, uint32_t* const dst);
- //------------------------------------------------------------------------------
- #ifdef __cplusplus
- } // extern "C"
- #endif
- #endif // WEBP_DSP_LOSSLESS_H_
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