// Copyright 2011 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.

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

//

// Speed-critical functions.

//

// Author: Skal (pascal.massimino@gmail.com)

#ifndef WEBP_DSP_DSP_H_

#define WEBP_DSP_DSP_H_

#ifdef HAVE_CONFIG_H

#include "src/webp/config.h"

#endif

#include "src/webp/types.h"

#ifdef __cplusplus

extern "C" {

#endif

#define BPS 32 // this is the common stride for enc/dec

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

// CPU detection

#if defined(__GNUC__)

# define LOCAL_GCC_VERSION ((__GNUC__ << 8) | __GNUC_MINOR__)

# define LOCAL_GCC_PREREQ(maj, min) \

(LOCAL_GCC_VERSION >= (((maj) << 8) | (min)))

#else

# define LOCAL_GCC_VERSION 0

# define LOCAL_GCC_PREREQ(maj, min) 0

#endif

#if defined(__clang__)

# define LOCAL_CLANG_VERSION ((__clang_major__ << 8) | __clang_minor__)

# define LOCAL_CLANG_PREREQ(maj, min) \

(LOCAL_CLANG_VERSION >= (((maj) << 8) | (min)))

#else

# define LOCAL_CLANG_VERSION 0

# define LOCAL_CLANG_PREREQ(maj, min) 0

#endif

#ifndef __has_builtin

# define __has_builtin(x) 0

#endif

// for now, none of the optimizations below are available in emscripten

#if !defined(EMSCRIPTEN)

#if defined(_MSC_VER) && _MSC_VER > 1310 && \

(defined(_M_X64) || defined(_M_IX86))

#define WEBP_MSC_SSE2 // Visual C++ SSE2 targets

#endif

#if defined(_MSC_VER) && _MSC_VER >= 1500 && \

(defined(_M_X64) || defined(_M_IX86))

#define WEBP_MSC_SSE41 // Visual C++ SSE4.1 targets

#endif

// WEBP_HAVE_* are used to indicate the presence of the instruction set in dsp

// files without intrinsics, allowing the corresponding Init() to be called.

// Files containing intrinsics will need to be built targeting the instruction

// set so should succeed on one of the earlier tests.

#if defined(__SSE2__) || defined(WEBP_MSC_SSE2) || defined(WEBP_HAVE_SSE2)

#define WEBP_USE_SSE2

#endif

#if defined(__SSE4_1__) || defined(WEBP_MSC_SSE41) || defined(WEBP_HAVE_SSE41)

#define WEBP_USE_SSE41

#endif

// The intrinsics currently cause compiler errors with arm-nacl-gcc and the

// inline assembly would need to be modified for use with Native Client.

#if (defined(__ARM_NEON__) || \

defined(__aarch64__) || defined(WEBP_HAVE_NEON)) && \

!defined(__native_client__)

#define WEBP_USE_NEON

#endif

#if !defined(WEBP_USE_NEON) && defined(__ANDROID__) && \

defined(__ARM_ARCH_7A__) && defined(HAVE_CPU_FEATURES_H)

#define WEBP_ANDROID_NEON // Android targets that may have NEON

#define WEBP_USE_NEON

#endif

#if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_M_ARM)

#define WEBP_USE_NEON

#define WEBP_USE_INTRINSICS

#endif

#if defined(__mips__) && !defined(__mips64) && \

defined(__mips_isa_rev) && (__mips_isa_rev >= 1) && (__mips_isa_rev < 6)

#define WEBP_USE_MIPS32

#if (__mips_isa_rev >= 2)

#define WEBP_USE_MIPS32_R2

#if defined(__mips_dspr2) || (defined(__mips_dsp_rev) && __mips_dsp_rev >= 2)

#define WEBP_USE_MIPS_DSP_R2

#endif

#endif

#endif

#if defined(__mips_msa) && defined(__mips_isa_rev) && (__mips_isa_rev >= 5)

#define WEBP_USE_MSA

#endif

#endif /* EMSCRIPTEN */

#ifndef WEBP_DSP_OMIT_C_CODE

#define WEBP_DSP_OMIT_C_CODE 1

#endif

#if (defined(__aarch64__) || defined(__ARM_NEON__)) && WEBP_DSP_OMIT_C_CODE

#define WEBP_NEON_OMIT_C_CODE 1

#else

#define WEBP_NEON_OMIT_C_CODE 0

#endif

#if !(LOCAL_CLANG_PREREQ(3,8) || LOCAL_GCC_PREREQ(4,8) || defined(__aarch64__))

#define WEBP_NEON_WORK_AROUND_GCC 1

#else

#define WEBP_NEON_WORK_AROUND_GCC 0

#endif

// This macro prevents thread_sanitizer from reporting known concurrent writes.

#define WEBP_TSAN_IGNORE_FUNCTION

#if defined(__has_feature)

#if __has_feature(thread_sanitizer)

#undef WEBP_TSAN_IGNORE_FUNCTION

#define WEBP_TSAN_IGNORE_FUNCTION __attribute__((no_sanitize_thread))

#endif

#endif

#if defined(WEBP_USE_THREAD) && !defined(_WIN32)

#include <pthread.h> // NOLINT

#define WEBP_DSP_INIT(func) do { \

static volatile VP8CPUInfo func ## _last_cpuinfo_used = \

(VP8CPUInfo)&func ## _last_cpuinfo_used; \

static pthread_mutex_t func ## _lock = PTHREAD_MUTEX_INITIALIZER; \

if (pthread_mutex_lock(&func ## _lock)) break; \

if (func ## _last_cpuinfo_used != VP8GetCPUInfo) func(); \

func ## _last_cpuinfo_used = VP8GetCPUInfo; \

(void)pthread_mutex_unlock(&func ## _lock); \

} while (0)

#else // !(defined(WEBP_USE_THREAD) && !defined(_WIN32))

#define WEBP_DSP_INIT(func) do { \

static volatile VP8CPUInfo func ## _last_cpuinfo_used = \

(VP8CPUInfo)&func ## _last_cpuinfo_used; \

if (func ## _last_cpuinfo_used == VP8GetCPUInfo) break; \

func(); \

func ## _last_cpuinfo_used = VP8GetCPUInfo; \

} while (0)

#endif // defined(WEBP_USE_THREAD) && !defined(_WIN32)

// Defines an Init + helper function that control multiple initialization of

// function pointers / tables.

/* Usage:

WEBP_DSP_INIT_FUNC(InitFunc) {

...function body

}

*/

#define WEBP_DSP_INIT_FUNC(name) \

static WEBP_TSAN_IGNORE_FUNCTION void name ## _body(void); \

WEBP_TSAN_IGNORE_FUNCTION void name(void) { \

WEBP_DSP_INIT(name ## _body); \

} \

static WEBP_TSAN_IGNORE_FUNCTION void name ## _body(void)

#define WEBP_UBSAN_IGNORE_UNDEF

#define WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW

#if defined(__clang__) && defined(__has_attribute)

#if __has_attribute(no_sanitize)

// This macro prevents the undefined behavior sanitizer from reporting

// failures. This is only meant to silence unaligned loads on platforms that

// are known to support them.

#undef WEBP_UBSAN_IGNORE_UNDEF

#define WEBP_UBSAN_IGNORE_UNDEF \

__attribute__((no_sanitize("undefined")))

// This macro prevents the undefined behavior sanitizer from reporting

// failures related to unsigned integer overflows. This is only meant to

// silence cases where this well defined behavior is expected.

#undef WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW

#define WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW \

__attribute__((no_sanitize("unsigned-integer-overflow")))

#endif

#endif

// Regularize the definition of WEBP_SWAP_16BIT_CSP (backward compatibility)

#if !defined(WEBP_SWAP_16BIT_CSP)

#define WEBP_SWAP_16BIT_CSP 0

#endif

// some endian fix (e.g.: mips-gcc doesn't define __BIG_ENDIAN__)

#if !defined(WORDS_BIGENDIAN) && \

(defined(__BIG_ENDIAN__) || defined(_M_PPC) || \

(defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)))

#define WORDS_BIGENDIAN

#endif

typedef enum {

kSSE2,

kSSE3,

kSlowSSSE3, // special feature for slow SSSE3 architectures

kSSE4_1,

kAVX,

kAVX2,

kNEON,

kMIPS32,

kMIPSdspR2,

kMSA

} CPUFeature;

// returns true if the CPU supports the feature.

typedef int (*VP8CPUInfo)(CPUFeature feature);

WEBP_EXTERN VP8CPUInfo VP8GetCPUInfo;

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

// Init stub generator

// Defines an init function stub to ensure each module exposes a symbol,

// avoiding a compiler warning.

#define WEBP_DSP_INIT_STUB(func) \

extern void func(void); \

void func(void) {}

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

// Encoding

// Transforms

// VP8Idct: Does one of two inverse transforms. If do_two is set, the transforms

// will be done for (ref, in, dst) and (ref + 4, in + 16, dst + 4).

typedef void (*VP8Idct)(const uint8_t* ref, const int16_t* in, uint8_t* dst,

int do_two);

typedef void (*VP8Fdct)(const uint8_t* src, const uint8_t* ref, int16_t* out);

typedef void (*VP8WHT)(const int16_t* in, int16_t* out);

extern VP8Idct VP8ITransform;

extern VP8Fdct VP8FTransform;

extern VP8Fdct VP8FTransform2; // performs two transforms at a time

extern VP8WHT VP8FTransformWHT;

// Predictions

// *dst is the destination block. *top and *left can be NULL.

typedef void (*VP8IntraPreds)(uint8_t *dst, const uint8_t* left,

const uint8_t* top);

typedef void (*VP8Intra4Preds)(uint8_t *dst, const uint8_t* top);

extern VP8Intra4Preds VP8EncPredLuma4;

extern VP8IntraPreds VP8EncPredLuma16;

extern VP8IntraPreds VP8EncPredChroma8;

typedef int (*VP8Metric)(const uint8_t* pix, const uint8_t* ref);

extern VP8Metric VP8SSE16x16, VP8SSE16x8, VP8SSE8x8, VP8SSE4x4;

typedef int (*VP8WMetric)(const uint8_t* pix, const uint8_t* ref,

const uint16_t* const weights);

// The weights for VP8TDisto4x4 and VP8TDisto16x16 contain a row-major

// 4 by 4 symmetric matrix.

extern VP8WMetric VP8TDisto4x4, VP8TDisto16x16;

// Compute the average (DC) of four 4x4 blocks.

// Each sub-4x4 block #i sum is stored in dc[i].

typedef void (*VP8MeanMetric)(const uint8_t* ref, uint32_t dc[4]);

extern VP8MeanMetric VP8Mean16x4;

typedef void (*VP8BlockCopy)(const uint8_t* src, uint8_t* dst);

extern VP8BlockCopy VP8Copy4x4;

extern VP8BlockCopy VP8Copy16x8;

// Quantization

struct VP8Matrix; // forward declaration

typedef int (*VP8QuantizeBlock)(int16_t in[16], int16_t out[16],

const struct VP8Matrix* const mtx);

// Same as VP8QuantizeBlock, but quantizes two consecutive blocks.

typedef int (*VP8Quantize2Blocks)(int16_t in[32], int16_t out[32],

const struct VP8Matrix* const mtx);

extern VP8QuantizeBlock VP8EncQuantizeBlock;

extern VP8Quantize2Blocks VP8EncQuantize2Blocks;

// specific to 2nd transform:

typedef int (*VP8QuantizeBlockWHT)(int16_t in[16], int16_t out[16],

const struct VP8Matrix* const mtx);

extern VP8QuantizeBlockWHT VP8EncQuantizeBlockWHT;

extern const int VP8DspScan[16 + 4 + 4];

// Collect histogram for susceptibility calculation.

#define MAX_COEFF_THRESH 31 // size of histogram used by CollectHistogram.

typedef struct {

// We only need to store max_value and last_non_zero, not the distribution.

int max_value;

int last_non_zero;

} VP8Histogram;

typedef void (*VP8CHisto)(const uint8_t* ref, const uint8_t* pred,

int start_block, int end_block,

VP8Histogram* const histo);

extern VP8CHisto VP8CollectHistogram;

// General-purpose util function to help VP8CollectHistogram().

void VP8SetHistogramData(const int distribution[MAX_COEFF_THRESH + 1],

VP8Histogram* const histo);

// must be called before using any of the above

void VP8EncDspInit(void);

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

// cost functions (encoding)

extern const uint16_t VP8EntropyCost[256]; // 8bit fixed-point log(p)

// approximate cost per level:

extern const uint16_t VP8LevelFixedCosts[2047 /*MAX_LEVEL*/ + 1];

extern const uint8_t VP8EncBands[16 + 1];

struct VP8Residual;

typedef void (*VP8SetResidualCoeffsFunc)(const int16_t* const coeffs,

struct VP8Residual* const res);

extern VP8SetResidualCoeffsFunc VP8SetResidualCoeffs;

// Cost calculation function.

typedef int (*VP8GetResidualCostFunc)(int ctx0,

const struct VP8Residual* const res);

extern VP8GetResidualCostFunc VP8GetResidualCost;

// must be called before anything using the above

void VP8EncDspCostInit(void);

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

// SSIM / PSNR utils

// struct for accumulating statistical moments

typedef struct {

uint32_t w; // sum(w_i) : sum of weights

uint32_t xm, ym; // sum(w_i * x_i), sum(w_i * y_i)

uint32_t xxm, xym, yym; // sum(w_i * x_i * x_i), etc.

} VP8DistoStats;

// Compute the final SSIM value

// The non-clipped version assumes stats->w = (2 * VP8_SSIM_KERNEL + 1)^2.

double VP8SSIMFromStats(const VP8DistoStats* const stats);

double VP8SSIMFromStatsClipped(const VP8DistoStats* const stats);

#define VP8_SSIM_KERNEL 3 // total size of the kernel: 2 * VP8_SSIM_KERNEL + 1

typedef double (*VP8SSIMGetClippedFunc)(const uint8_t* src1, int stride1,

const uint8_t* src2, int stride2,

int xo, int yo, // center position

int W, int H); // plane dimension

#if !defined(WEBP_REDUCE_SIZE)

// This version is called with the guarantee that you can load 8 bytes and

// 8 rows at offset src1 and src2

typedef double (*VP8SSIMGetFunc)(const uint8_t* src1, int stride1,

const uint8_t* src2, int stride2);

extern VP8SSIMGetFunc VP8SSIMGet; // unclipped / unchecked

extern VP8SSIMGetClippedFunc VP8SSIMGetClipped; // with clipping

#endif

#if !defined(WEBP_DISABLE_STATS)

typedef uint32_t (*VP8AccumulateSSEFunc)(const uint8_t* src1,

const uint8_t* src2, int len);

extern VP8AccumulateSSEFunc VP8AccumulateSSE;

#endif

// must be called before using any of the above directly

void VP8SSIMDspInit(void);

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

// Decoding

typedef void (*VP8DecIdct)(const int16_t* coeffs, uint8_t* dst);

// when doing two transforms, coeffs is actually int16_t[2][16].

typedef void (*VP8DecIdct2)(const int16_t* coeffs, uint8_t* dst, int do_two);

extern VP8DecIdct2 VP8Transform;

extern VP8DecIdct VP8TransformAC3;

extern VP8DecIdct VP8TransformUV;

extern VP8DecIdct VP8TransformDC;

extern VP8DecIdct VP8TransformDCUV;

extern VP8WHT VP8TransformWHT;

// *dst is the destination block, with stride BPS. Boundary samples are

// assumed accessible when needed.

typedef void (*VP8PredFunc)(uint8_t* dst);

extern VP8PredFunc VP8PredLuma16[/* NUM_B_DC_MODES */];

extern VP8PredFunc VP8PredChroma8[/* NUM_B_DC_MODES */];

extern VP8PredFunc VP8PredLuma4[/* NUM_BMODES */];

// clipping tables (for filtering)

extern const int8_t* const VP8ksclip1; // clips [-1020, 1020] to [-128, 127]

extern const int8_t* const VP8ksclip2; // clips [-112, 112] to [-16, 15]

extern const uint8_t* const VP8kclip1; // clips [-255,511] to [0,255]

extern const uint8_t* const VP8kabs0; // abs(x) for x in [-255,255]

// must be called first

void VP8InitClipTables(void);

// simple filter (only for luma)

typedef void (*VP8SimpleFilterFunc)(uint8_t* p, int stride, int thresh);

extern VP8SimpleFilterFunc VP8SimpleVFilter16;

extern VP8SimpleFilterFunc VP8SimpleHFilter16;

extern VP8SimpleFilterFunc VP8SimpleVFilter16i; // filter 3 inner edges

extern VP8SimpleFilterFunc VP8SimpleHFilter16i;

// regular filter (on both macroblock edges and inner edges)

typedef void (*VP8LumaFilterFunc)(uint8_t* luma, int stride,

int thresh, int ithresh, int hev_t);

typedef void (*VP8ChromaFilterFunc)(uint8_t* u, uint8_t* v, int stride,

int thresh, int ithresh, int hev_t);

// on outer edge

extern VP8LumaFilterFunc VP8VFilter16;

extern VP8LumaFilterFunc VP8HFilter16;

extern VP8ChromaFilterFunc VP8VFilter8;

extern VP8ChromaFilterFunc VP8HFilter8;

// on inner edge

extern VP8LumaFilterFunc VP8VFilter16i; // filtering 3 inner edges altogether

extern VP8LumaFilterFunc VP8HFilter16i;

extern VP8ChromaFilterFunc VP8VFilter8i; // filtering u and v altogether

extern VP8ChromaFilterFunc VP8HFilter8i;

// Dithering. Combines dithering values (centered around 128) with dst[],

// according to: dst[] = clip(dst[] + (((dither[]-128) + 8) >> 4)

#define VP8_DITHER_DESCALE 4

#define VP8_DITHER_DESCALE_ROUNDER (1 << (VP8_DITHER_DESCALE - 1))

#define VP8_DITHER_AMP_BITS 7

#define VP8_DITHER_AMP_CENTER (1 << VP8_DITHER_AMP_BITS)

extern void (*VP8DitherCombine8x8)(const uint8_t* dither, uint8_t* dst,

int dst_stride);

// must be called before anything using the above

void VP8DspInit(void);

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

// WebP I/O

#define FANCY_UPSAMPLING // undefined to remove fancy upsampling support

// Convert a pair of y/u/v lines together to the output rgb/a colorspace.

// bottom_y can be NULL if only one line of output is needed (at top/bottom).

typedef void (*WebPUpsampleLinePairFunc)(

const uint8_t* top_y, const uint8_t* bottom_y,

const uint8_t* top_u, const uint8_t* top_v,

const uint8_t* cur_u, const uint8_t* cur_v,

uint8_t* top_dst, uint8_t* bottom_dst, int len);

#ifdef FANCY_UPSAMPLING

// Fancy upsampling functions to convert YUV to RGB(A) modes

extern WebPUpsampleLinePairFunc WebPUpsamplers[/* MODE_LAST */];

#endif // FANCY_UPSAMPLING

// Per-row point-sampling methods.

typedef void (*WebPSamplerRowFunc)(const uint8_t* y,

const uint8_t* u, const uint8_t* v,

uint8_t* dst, int len);

// Generic function to apply 'WebPSamplerRowFunc' to the whole plane:

void WebPSamplerProcessPlane(const uint8_t* y, int y_stride,

const uint8_t* u, const uint8_t* v, int uv_stride,

uint8_t* dst, int dst_stride,

int width, int height, WebPSamplerRowFunc func);

// Sampling functions to convert rows of YUV to RGB(A)

extern WebPSamplerRowFunc WebPSamplers[/* MODE_LAST */];

// General function for converting two lines of ARGB or RGBA.

// 'alpha_is_last' should be true if 0xff000000 is stored in memory as

// as 0x00, 0x00, 0x00, 0xff (little endian).

WebPUpsampleLinePairFunc WebPGetLinePairConverter(int alpha_is_last);

// YUV444->RGB converters

typedef void (*WebPYUV444Converter)(const uint8_t* y,

const uint8_t* u, const uint8_t* v,

uint8_t* dst, int len);

extern WebPYUV444Converter WebPYUV444Converters[/* MODE_LAST */];

// Must be called before using the WebPUpsamplers[] (and for premultiplied

// colorspaces like rgbA, rgbA4444, etc)

void WebPInitUpsamplers(void);

// Must be called before using WebPSamplers[]

void WebPInitSamplers(void);

// Must be called before using WebPYUV444Converters[]

void WebPInitYUV444Converters(void);

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

// ARGB -> YUV converters

// Convert ARGB samples to luma Y.

extern void (*WebPConvertARGBToY)(const uint32_t* argb, uint8_t* y, int width);

// Convert ARGB samples to U/V with downsampling. do_store should be '1' for

// even lines and '0' for odd ones. 'src_width' is the original width, not

// the U/V one.

extern void (*WebPConvertARGBToUV)(const uint32_t* argb, uint8_t* u, uint8_t* v,

int src_width, int do_store);

// Convert a row of accumulated (four-values) of rgba32 toward U/V

extern void (*WebPConvertRGBA32ToUV)(const uint16_t* rgb,

uint8_t* u, uint8_t* v, int width);

// Convert RGB or BGR to Y

extern void (*WebPConvertRGB24ToY)(const uint8_t* rgb, uint8_t* y, int width);

extern void (*WebPConvertBGR24ToY)(const uint8_t* bgr, uint8_t* y, int width);

// used for plain-C fallback.

extern void WebPConvertARGBToUV_C(const uint32_t* argb, uint8_t* u, uint8_t* v,

int src_width, int do_store);

extern void WebPConvertRGBA32ToUV_C(const uint16_t* rgb,

uint8_t* u, uint8_t* v, int width);

// utilities for accurate RGB->YUV conversion

extern uint64_t (*WebPSharpYUVUpdateY)(const uint16_t* src, const uint16_t* ref,

uint16_t* dst, int len);

extern void (*WebPSharpYUVUpdateRGB)(const int16_t* src, const int16_t* ref,

int16_t* dst, int len);

extern void (*WebPSharpYUVFilterRow)(const int16_t* A, const int16_t* B,

int len,

const uint16_t* best_y, uint16_t* out);

// Must be called before using the above.

void WebPInitConvertARGBToYUV(void);

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

// Rescaler

struct WebPRescaler;

// Import a row of data and save its contribution in the rescaler.

// 'channel' denotes the channel number to be imported. 'Expand' corresponds to

// the wrk->x_expand case. Otherwise, 'Shrink' is to be used.

typedef void (*WebPRescalerImportRowFunc)(struct WebPRescaler* const wrk,

const uint8_t* src);

extern WebPRescalerImportRowFunc WebPRescalerImportRowExpand;

extern WebPRescalerImportRowFunc WebPRescalerImportRowShrink;

// Export one row (starting at x_out position) from rescaler.

// 'Expand' corresponds to the wrk->y_expand case.

// Otherwise 'Shrink' is to be used

typedef void (*WebPRescalerExportRowFunc)(struct WebPRescaler* const wrk);

extern WebPRescalerExportRowFunc WebPRescalerExportRowExpand;

extern WebPRescalerExportRowFunc WebPRescalerExportRowShrink;

// Plain-C implementation, as fall-back.

extern void WebPRescalerImportRowExpand_C(struct WebPRescaler* const wrk,

const uint8_t* src);

extern void WebPRescalerImportRowShrink_C(struct WebPRescaler* const wrk,

const uint8_t* src);

extern void WebPRescalerExportRowExpand_C(struct WebPRescaler* const wrk);

extern void WebPRescalerExportRowShrink_C(struct WebPRescaler* const wrk);

// Main entry calls:

extern void WebPRescalerImportRow(struct WebPRescaler* const wrk,

const uint8_t* src);

// Export one row (starting at x_out position) from rescaler.

extern void WebPRescalerExportRow(struct WebPRescaler* const wrk);

// Must be called first before using the above.

void WebPRescalerDspInit(void);

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

// Utilities for processing transparent channel.

// Apply alpha pre-multiply on an rgba, bgra or argb plane of size w * h.

// alpha_first should be 0 for argb, 1 for rgba or bgra (where alpha is last).

extern void (*WebPApplyAlphaMultiply)(

uint8_t* rgba, int alpha_first, int w, int h, int stride);

// Same, buf specifically for RGBA4444 format

extern void (*WebPApplyAlphaMultiply4444)(

uint8_t* rgba4444, int w, int h, int stride);

// Dispatch the values from alpha[] plane to the ARGB destination 'dst'.

// Returns true if alpha[] plane has non-trivial values different from 0xff.

extern int (*WebPDispatchAlpha)(const uint8_t* alpha, int alpha_stride,

int width, int height,

uint8_t* dst, int dst_stride);

// Transfer packed 8b alpha[] values to green channel in dst[], zero'ing the

// A/R/B values. 'dst_stride' is the stride for dst[] in uint32_t units.

extern void (*WebPDispatchAlphaToGreen)(const uint8_t* alpha, int alpha_stride,

int width, int height,

uint32_t* dst, int dst_stride);

// Extract the alpha values from 32b values in argb[] and pack them into alpha[]

// (this is the opposite of WebPDispatchAlpha).

// Returns true if there's only trivial 0xff alpha values.

extern int (*WebPExtractAlpha)(const uint8_t* argb, int argb_stride,

int width, int height,

uint8_t* alpha, int alpha_stride);

// Extract the green values from 32b values in argb[] and pack them into alpha[]

// (this is the opposite of WebPDispatchAlphaToGreen).

extern void (*WebPExtractGreen)(const uint32_t* argb, uint8_t* alpha, int size);

// Pre-Multiply operation transforms x into x * A / 255 (where x=Y,R,G or B).

// Un-Multiply operation transforms x into x * 255 / A.

// Pre-Multiply or Un-Multiply (if 'inverse' is true) argb values in a row.

extern void (*WebPMultARGBRow)(uint32_t* const ptr, int width, int inverse);

// Same a WebPMultARGBRow(), but for several rows.

void WebPMultARGBRows(uint8_t* ptr, int stride, int width, int num_rows,

int inverse);

// Same for a row of single values, with side alpha values.

extern void (*WebPMultRow)(uint8_t* const ptr, const uint8_t* const alpha,

int width, int inverse);

// Same a WebPMultRow(), but for several 'num_rows' rows.

void WebPMultRows(uint8_t* ptr, int stride,

const uint8_t* alpha, int alpha_stride,

int width, int num_rows, int inverse);

// Plain-C versions, used as fallback by some implementations.

void WebPMultRow_C(uint8_t* const ptr, const uint8_t* const alpha,

int width, int inverse);

void WebPMultARGBRow_C(uint32_t* const ptr, int width, int inverse);

#ifdef WORDS_BIGENDIAN

// ARGB packing function: a/r/g/b input is rgba or bgra order.

extern void (*WebPPackARGB)(const uint8_t* a, const uint8_t* r,

const uint8_t* g, const uint8_t* b, int len,

uint32_t* out);

#endif

// RGB packing function. 'step' can be 3 or 4. r/g/b input is rgb or bgr order.

extern void (*WebPPackRGB)(const uint8_t* r, const uint8_t* g, const uint8_t* b,

int len, int step, uint32_t* out);

// This function returns true if src[i] contains a value different from 0xff.

extern int (*WebPHasAlpha8b)(const uint8_t* src, int length);

// This function returns true if src[4*i] contains a value different from 0xff.

extern int (*WebPHasAlpha32b)(const uint8_t* src, int length);

// To be called first before using the above.

void WebPInitAlphaProcessing(void);

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

// Filter functions

typedef enum { // Filter types.

WEBP_FILTER_NONE = 0,

WEBP_FILTER_HORIZONTAL,

WEBP_FILTER_VERTICAL,

WEBP_FILTER_GRADIENT,

WEBP_FILTER_LAST = WEBP_FILTER_GRADIENT + 1, // end marker

WEBP_FILTER_BEST, // meta-types

WEBP_FILTER_FAST

} WEBP_FILTER_TYPE;

typedef void (*WebPFilterFunc)(const uint8_t* in, int width, int height,

int stride, uint8_t* out);

// In-place un-filtering.

// Warning! 'prev_line' pointer can be equal to 'cur_line' or 'preds'.

typedef void (*WebPUnfilterFunc)(const uint8_t* prev_line, const uint8_t* preds,

uint8_t* cur_line, int width);

// Filter the given data using the given predictor.

// 'in' corresponds to a 2-dimensional pixel array of size (stride * height)

// in raster order.

// 'stride' is number of bytes per scan line (with possible padding).

// 'out' should be pre-allocated.

extern WebPFilterFunc WebPFilters[WEBP_FILTER_LAST];

// In-place reconstruct the original data from the given filtered data.

// The reconstruction will be done for 'num_rows' rows starting from 'row'

// (assuming rows upto 'row - 1' are already reconstructed).

extern WebPUnfilterFunc WebPUnfilters[WEBP_FILTER_LAST];

// To be called first before using the above.

void VP8FiltersInit(void);

#ifdef __cplusplus

} // extern "C"

#endif

#endif // WEBP_DSP_DSP_H_