// 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.

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

//

// functions for sample output.

//

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

#include <assert.h>

#include <stdlib.h>

#include "src/dec/vp8i_dec.h"

#include "src/dec/webpi_dec.h"

#include "src/dsp/dsp.h"

#include "src/dsp/yuv.h"

#include "src/utils/utils.h"

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

// Main YUV<->RGB conversion functions

static int EmitYUV(const VP8Io* const io, WebPDecParams* const p) {

WebPDecBuffer* output = p->output;

const WebPYUVABuffer* const buf = &output->u.YUVA;

uint8_t* const y_dst = buf->y + io->mb_y * buf->y_stride;

uint8_t* const u_dst = buf->u + (io->mb_y >> 1) * buf->u_stride;

uint8_t* const v_dst = buf->v + (io->mb_y >> 1) * buf->v_stride;

const int mb_w = io->mb_w;

const int mb_h = io->mb_h;

const int uv_w = (mb_w + 1) / 2;

const int uv_h = (mb_h + 1) / 2;

int j;

for (j = 0; j < mb_h; ++j) {

memcpy(y_dst + j * buf->y_stride, io->y + j * io->y_stride, mb_w);

}

for (j = 0; j < uv_h; ++j) {

memcpy(u_dst + j * buf->u_stride, io->u + j * io->uv_stride, uv_w);

memcpy(v_dst + j * buf->v_stride, io->v + j * io->uv_stride, uv_w);

}

return io->mb_h;

}

// Point-sampling U/V sampler.

static int EmitSampledRGB(const VP8Io* const io, WebPDecParams* const p) {

WebPDecBuffer* const output = p->output;

WebPRGBABuffer* const buf = &output->u.RGBA;

uint8_t* const dst = buf->rgba + io->mb_y * buf->stride;

WebPSamplerProcessPlane(io->y, io->y_stride,

io->u, io->v, io->uv_stride,

dst, buf->stride, io->mb_w, io->mb_h,

WebPSamplers[output->colorspace]);

return io->mb_h;

}

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

// Fancy upsampling

#ifdef FANCY_UPSAMPLING

static int EmitFancyRGB(const VP8Io* const io, WebPDecParams* const p) {

int num_lines_out = io->mb_h; // a priori guess

const WebPRGBABuffer* const buf = &p->output->u.RGBA;

uint8_t* dst = buf->rgba + io->mb_y * buf->stride;

WebPUpsampleLinePairFunc upsample = WebPUpsamplers[p->output->colorspace];

const uint8_t* cur_y = io->y;

const uint8_t* cur_u = io->u;

const uint8_t* cur_v = io->v;

const uint8_t* top_u = p->tmp_u;

const uint8_t* top_v = p->tmp_v;

int y = io->mb_y;

const int y_end = io->mb_y + io->mb_h;

const int mb_w = io->mb_w;

const int uv_w = (mb_w + 1) / 2;

if (y == 0) {

// First line is special cased. We mirror the u/v samples at boundary.

upsample(cur_y, NULL, cur_u, cur_v, cur_u, cur_v, dst, NULL, mb_w);

} else {

// We can finish the left-over line from previous call.

upsample(p->tmp_y, cur_y, top_u, top_v, cur_u, cur_v,

dst - buf->stride, dst, mb_w);

++num_lines_out;

}

// Loop over each output pairs of row.

for (; y + 2 < y_end; y += 2) {

top_u = cur_u;

top_v = cur_v;

cur_u += io->uv_stride;

cur_v += io->uv_stride;

dst += 2 * buf->stride;

cur_y += 2 * io->y_stride;

upsample(cur_y - io->y_stride, cur_y,

top_u, top_v, cur_u, cur_v,

dst - buf->stride, dst, mb_w);

}

// move to last row

cur_y += io->y_stride;

if (io->crop_top + y_end < io->crop_bottom) {

// Save the unfinished samples for next call (as we're not done yet).

memcpy(p->tmp_y, cur_y, mb_w * sizeof(*p->tmp_y));

memcpy(p->tmp_u, cur_u, uv_w * sizeof(*p->tmp_u));

memcpy(p->tmp_v, cur_v, uv_w * sizeof(*p->tmp_v));

// The fancy upsampler leaves a row unfinished behind

// (except for the very last row)

num_lines_out--;

} else {

// Process the very last row of even-sized picture

if (!(y_end & 1)) {

upsample(cur_y, NULL, cur_u, cur_v, cur_u, cur_v,

dst + buf->stride, NULL, mb_w);

}

}

return num_lines_out;

}

#endif /* FANCY_UPSAMPLING */

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

static void FillAlphaPlane(uint8_t* dst, int w, int h, int stride) {

int j;

for (j = 0; j < h; ++j) {

memset(dst, 0xff, w * sizeof(*dst));

dst += stride;

}

}

static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,

int expected_num_lines_out) {

const uint8_t* alpha = io->a;

const WebPYUVABuffer* const buf = &p->output->u.YUVA;

const int mb_w = io->mb_w;

const int mb_h = io->mb_h;

uint8_t* dst = buf->a + io->mb_y * buf->a_stride;

int j;

(void)expected_num_lines_out;

assert(expected_num_lines_out == mb_h);

if (alpha != NULL) {

for (j = 0; j < mb_h; ++j) {

memcpy(dst, alpha, mb_w * sizeof(*dst));

alpha += io->width;

dst += buf->a_stride;

}

} else if (buf->a != NULL) {

// the user requested alpha, but there is none, set it to opaque.

FillAlphaPlane(dst, mb_w, mb_h, buf->a_stride);

}

return 0;

}

static int GetAlphaSourceRow(const VP8Io* const io,

const uint8_t** alpha, int* const num_rows) {

int start_y = io->mb_y;

*num_rows = io->mb_h;

// Compensate for the 1-line delay of the fancy upscaler.

// This is similar to EmitFancyRGB().

if (io->fancy_upsampling) {

if (start_y == 0) {

// We don't process the last row yet. It'll be done during the next call.

--*num_rows;

} else {

--start_y;

// Fortunately, *alpha data is persistent, so we can go back

// one row and finish alpha blending, now that the fancy upscaler

// completed the YUV->RGB interpolation.

*alpha -= io->width;

}

if (io->crop_top + io->mb_y + io->mb_h == io->crop_bottom) {

// If it's the very last call, we process all the remaining rows!

*num_rows = io->crop_bottom - io->crop_top - start_y;

}

}

return start_y;

}

static int EmitAlphaRGB(const VP8Io* const io, WebPDecParams* const p,

int expected_num_lines_out) {

const uint8_t* alpha = io->a;

if (alpha != NULL) {

const int mb_w = io->mb_w;

const WEBP_CSP_MODE colorspace = p->output->colorspace;

const int alpha_first =

(colorspace == MODE_ARGB || colorspace == MODE_Argb);

const WebPRGBABuffer* const buf = &p->output->u.RGBA;

int num_rows;

const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);

uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;

uint8_t* const dst = base_rgba + (alpha_first ? 0 : 3);

const int has_alpha = WebPDispatchAlpha(alpha, io->width, mb_w,

num_rows, dst, buf->stride);

(void)expected_num_lines_out;

assert(expected_num_lines_out == num_rows);

// has_alpha is true if there's non-trivial alpha to premultiply with.

if (has_alpha && WebPIsPremultipliedMode(colorspace)) {

WebPApplyAlphaMultiply(base_rgba, alpha_first,

mb_w, num_rows, buf->stride);

}

}

return 0;

}

static int EmitAlphaRGBA4444(const VP8Io* const io, WebPDecParams* const p,

int expected_num_lines_out) {

const uint8_t* alpha = io->a;

if (alpha != NULL) {

const int mb_w = io->mb_w;

const WEBP_CSP_MODE colorspace = p->output->colorspace;

const WebPRGBABuffer* const buf = &p->output->u.RGBA;

int num_rows;

const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);

uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;

#if (WEBP_SWAP_16BIT_CSP == 1)

uint8_t* alpha_dst = base_rgba;

#else

uint8_t* alpha_dst = base_rgba + 1;

#endif

uint32_t alpha_mask = 0x0f;

int i, j;

for (j = 0; j < num_rows; ++j) {

for (i = 0; i < mb_w; ++i) {

// Fill in the alpha value (converted to 4 bits).

const uint32_t alpha_value = alpha[i] >> 4;

alpha_dst[2 * i] = (alpha_dst[2 * i] & 0xf0) | alpha_value;

alpha_mask &= alpha_value;

}

alpha += io->width;

alpha_dst += buf->stride;

}

(void)expected_num_lines_out;

assert(expected_num_lines_out == num_rows);

if (alpha_mask != 0x0f && WebPIsPremultipliedMode(colorspace)) {

WebPApplyAlphaMultiply4444(base_rgba, mb_w, num_rows, buf->stride);

}

}

return 0;

}

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

// YUV rescaling (no final RGB conversion needed)

#if !defined(WEBP_REDUCE_SIZE)

static int Rescale(const uint8_t* src, int src_stride,

int new_lines, WebPRescaler* const wrk) {

int num_lines_out = 0;

while (new_lines > 0) { // import new contributions of source rows.

const int lines_in = WebPRescalerImport(wrk, new_lines, src, src_stride);

src += lines_in * src_stride;

new_lines -= lines_in;

num_lines_out += WebPRescalerExport(wrk); // emit output row(s)

}

return num_lines_out;

}

static int EmitRescaledYUV(const VP8Io* const io, WebPDecParams* const p) {

const int mb_h = io->mb_h;

const int uv_mb_h = (mb_h + 1) >> 1;

WebPRescaler* const scaler = p->scaler_y;

int num_lines_out = 0;

if (WebPIsAlphaMode(p->output->colorspace) && io->a != NULL) {

// Before rescaling, we premultiply the luma directly into the io->y

// internal buffer. This is OK since these samples are not used for

// intra-prediction (the top samples are saved in cache_y_/u_/v_).

// But we need to cast the const away, though.

WebPMultRows((uint8_t*)io->y, io->y_stride,

io->a, io->width, io->mb_w, mb_h, 0);

}

num_lines_out = Rescale(io->y, io->y_stride, mb_h, scaler);

Rescale(io->u, io->uv_stride, uv_mb_h, p->scaler_u);

Rescale(io->v, io->uv_stride, uv_mb_h, p->scaler_v);

return num_lines_out;

}

static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p,

int expected_num_lines_out) {

const WebPYUVABuffer* const buf = &p->output->u.YUVA;

uint8_t* const dst_a = buf->a + p->last_y * buf->a_stride;

if (io->a != NULL) {

uint8_t* const dst_y = buf->y + p->last_y * buf->y_stride;

const int num_lines_out = Rescale(io->a, io->width, io->mb_h, p->scaler_a);

assert(expected_num_lines_out == num_lines_out);

if (num_lines_out > 0) { // unmultiply the Y

WebPMultRows(dst_y, buf->y_stride, dst_a, buf->a_stride,

p->scaler_a->dst_width, num_lines_out, 1);

}

} else if (buf->a != NULL) {

// the user requested alpha, but there is none, set it to opaque.

assert(p->last_y + expected_num_lines_out <= io->scaled_height);

FillAlphaPlane(dst_a, io->scaled_width, expected_num_lines_out,

buf->a_stride);

}

return 0;

}

static int InitYUVRescaler(const VP8Io* const io, WebPDecParams* const p) {

const int has_alpha = WebPIsAlphaMode(p->output->colorspace);

const WebPYUVABuffer* const buf = &p->output->u.YUVA;

const int out_width = io->scaled_width;

const int out_height = io->scaled_height;

const int uv_out_width = (out_width + 1) >> 1;

const int uv_out_height = (out_height + 1) >> 1;

const int uv_in_width = (io->mb_w + 1) >> 1;

const int uv_in_height = (io->mb_h + 1) >> 1;

const size_t work_size = 2 * out_width; // scratch memory for luma rescaler

const size_t uv_work_size = 2 * uv_out_width; // and for each u/v ones

size_t tmp_size, rescaler_size;

rescaler_t* work;

WebPRescaler* scalers;

const int num_rescalers = has_alpha ? 4 : 3;

tmp_size = (work_size + 2 * uv_work_size) * sizeof(*work);

if (has_alpha) {

tmp_size += work_size * sizeof(*work);

}

rescaler_size = num_rescalers * sizeof(*p->scaler_y) + WEBP_ALIGN_CST;

p->memory = WebPSafeMalloc(1ULL, tmp_size + rescaler_size);

if (p->memory == NULL) {

return 0; // memory error

}

work = (rescaler_t*)p->memory;

scalers = (WebPRescaler*)WEBP_ALIGN((const uint8_t*)work + tmp_size);

p->scaler_y = &scalers[0];

p->scaler_u = &scalers[1];

p->scaler_v = &scalers[2];

p->scaler_a = has_alpha ? &scalers[3] : NULL;

WebPRescalerInit(p->scaler_y, io->mb_w, io->mb_h,

buf->y, out_width, out_height, buf->y_stride, 1,

work);

WebPRescalerInit(p->scaler_u, uv_in_width, uv_in_height,

buf->u, uv_out_width, uv_out_height, buf->u_stride, 1,

work + work_size);

WebPRescalerInit(p->scaler_v, uv_in_width, uv_in_height,

buf->v, uv_out_width, uv_out_height, buf->v_stride, 1,

work + work_size + uv_work_size);

p->emit = EmitRescaledYUV;

if (has_alpha) {

WebPRescalerInit(p->scaler_a, io->mb_w, io->mb_h,

buf->a, out_width, out_height, buf->a_stride, 1,

work + work_size + 2 * uv_work_size);

p->emit_alpha = EmitRescaledAlphaYUV;

WebPInitAlphaProcessing();

}

return 1;

}

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

// RGBA rescaling

static int ExportRGB(WebPDecParams* const p, int y_pos) {

const WebPYUV444Converter convert =

WebPYUV444Converters[p->output->colorspace];

const WebPRGBABuffer* const buf = &p->output->u.RGBA;

uint8_t* dst = buf->rgba + y_pos * buf->stride;

int num_lines_out = 0;

// For RGB rescaling, because of the YUV420, current scan position

// U/V can be +1/-1 line from the Y one. Hence the double test.

while (WebPRescalerHasPendingOutput(p->scaler_y) &&

WebPRescalerHasPendingOutput(p->scaler_u)) {

assert(y_pos + num_lines_out < p->output->height);

assert(p->scaler_u->y_accum == p->scaler_v->y_accum);

WebPRescalerExportRow(p->scaler_y);

WebPRescalerExportRow(p->scaler_u);

WebPRescalerExportRow(p->scaler_v);

convert(p->scaler_y->dst, p->scaler_u->dst, p->scaler_v->dst,

dst, p->scaler_y->dst_width);

dst += buf->stride;

++num_lines_out;

}

return num_lines_out;

}

static int EmitRescaledRGB(const VP8Io* const io, WebPDecParams* const p) {

const int mb_h = io->mb_h;

const int uv_mb_h = (mb_h + 1) >> 1;

int j = 0, uv_j = 0;

int num_lines_out = 0;

while (j < mb_h) {

const int y_lines_in =

WebPRescalerImport(p->scaler_y, mb_h - j,

io->y + j * io->y_stride, io->y_stride);

j += y_lines_in;

if (WebPRescaleNeededLines(p->scaler_u, uv_mb_h - uv_j)) {

const int u_lines_in =

WebPRescalerImport(p->scaler_u, uv_mb_h - uv_j,

io->u + uv_j * io->uv_stride, io->uv_stride);

const int v_lines_in =

WebPRescalerImport(p->scaler_v, uv_mb_h - uv_j,

io->v + uv_j * io->uv_stride, io->uv_stride);

(void)v_lines_in; // remove a gcc warning

assert(u_lines_in == v_lines_in);

uv_j += u_lines_in;

}

num_lines_out += ExportRGB(p, p->last_y + num_lines_out);

}

return num_lines_out;

}

static int ExportAlpha(WebPDecParams* const p, int y_pos, int max_lines_out) {

const WebPRGBABuffer* const buf = &p->output->u.RGBA;

uint8_t* const base_rgba = buf->rgba + y_pos * buf->stride;

const WEBP_CSP_MODE colorspace = p->output->colorspace;

const int alpha_first =

(colorspace == MODE_ARGB || colorspace == MODE_Argb);

uint8_t* dst = base_rgba + (alpha_first ? 0 : 3);

int num_lines_out = 0;

const int is_premult_alpha = WebPIsPremultipliedMode(colorspace);

uint32_t non_opaque = 0;

const int width = p->scaler_a->dst_width;

while (WebPRescalerHasPendingOutput(p->scaler_a) &&

num_lines_out < max_lines_out) {

assert(y_pos + num_lines_out < p->output->height);

WebPRescalerExportRow(p->scaler_a);

non_opaque |= WebPDispatchAlpha(p->scaler_a->dst, 0, width, 1, dst, 0);

dst += buf->stride;

++num_lines_out;

}

if (is_premult_alpha && non_opaque) {

WebPApplyAlphaMultiply(base_rgba, alpha_first,

width, num_lines_out, buf->stride);

}

return num_lines_out;

}

static int ExportAlphaRGBA4444(WebPDecParams* const p, int y_pos,

int max_lines_out) {

const WebPRGBABuffer* const buf = &p->output->u.RGBA;

uint8_t* const base_rgba = buf->rgba + y_pos * buf->stride;

#if (WEBP_SWAP_16BIT_CSP == 1)

uint8_t* alpha_dst = base_rgba;

#else

uint8_t* alpha_dst = base_rgba + 1;

#endif

int num_lines_out = 0;

const WEBP_CSP_MODE colorspace = p->output->colorspace;

const int width = p->scaler_a->dst_width;

const int is_premult_alpha = WebPIsPremultipliedMode(colorspace);

uint32_t alpha_mask = 0x0f;

while (WebPRescalerHasPendingOutput(p->scaler_a) &&

num_lines_out < max_lines_out) {

int i;

assert(y_pos + num_lines_out < p->output->height);

WebPRescalerExportRow(p->scaler_a);

for (i = 0; i < width; ++i) {

// Fill in the alpha value (converted to 4 bits).

const uint32_t alpha_value = p->scaler_a->dst[i] >> 4;

alpha_dst[2 * i] = (alpha_dst[2 * i] & 0xf0) | alpha_value;

alpha_mask &= alpha_value;

}

alpha_dst += buf->stride;

++num_lines_out;

}

if (is_premult_alpha && alpha_mask != 0x0f) {

WebPApplyAlphaMultiply4444(base_rgba, width, num_lines_out, buf->stride);

}

return num_lines_out;

}

static int EmitRescaledAlphaRGB(const VP8Io* const io, WebPDecParams* const p,

int expected_num_out_lines) {

if (io->a != NULL) {

WebPRescaler* const scaler = p->scaler_a;

int lines_left = expected_num_out_lines;

const int y_end = p->last_y + lines_left;

while (lines_left > 0) {

const int row_offset = scaler->src_y - io->mb_y;

WebPRescalerImport(scaler, io->mb_h + io->mb_y - scaler->src_y,

io->a + row_offset * io->width, io->width);

lines_left -= p->emit_alpha_row(p, y_end - lines_left, lines_left);

}

}

return 0;

}

static int InitRGBRescaler(const VP8Io* const io, WebPDecParams* const p) {

const int has_alpha = WebPIsAlphaMode(p->output->colorspace);

const int out_width = io->scaled_width;

const int out_height = io->scaled_height;

const int uv_in_width = (io->mb_w + 1) >> 1;

const int uv_in_height = (io->mb_h + 1) >> 1;

const size_t work_size = 2 * out_width; // scratch memory for one rescaler

rescaler_t* work; // rescalers work area

uint8_t* tmp; // tmp storage for scaled YUV444 samples before RGB conversion

size_t tmp_size1, tmp_size2, total_size, rescaler_size;

WebPRescaler* scalers;

const int num_rescalers = has_alpha ? 4 : 3;

tmp_size1 = 3 * work_size;

tmp_size2 = 3 * out_width;

if (has_alpha) {

tmp_size1 += work_size;

tmp_size2 += out_width;

}

total_size = tmp_size1 * sizeof(*work) + tmp_size2 * sizeof(*tmp);

rescaler_size = num_rescalers * sizeof(*p->scaler_y) + WEBP_ALIGN_CST;

p->memory = WebPSafeMalloc(1ULL, total_size + rescaler_size);

if (p->memory == NULL) {

return 0; // memory error

}

work = (rescaler_t*)p->memory;

tmp = (uint8_t*)(work + tmp_size1);

scalers = (WebPRescaler*)WEBP_ALIGN((const uint8_t*)work + total_size);

p->scaler_y = &scalers[0];

p->scaler_u = &scalers[1];

p->scaler_v = &scalers[2];

p->scaler_a = has_alpha ? &scalers[3] : NULL;

WebPRescalerInit(p->scaler_y, io->mb_w, io->mb_h,

tmp + 0 * out_width, out_width, out_height, 0, 1,

work + 0 * work_size);

WebPRescalerInit(p->scaler_u, uv_in_width, uv_in_height,

tmp + 1 * out_width, out_width, out_height, 0, 1,

work + 1 * work_size);

WebPRescalerInit(p->scaler_v, uv_in_width, uv_in_height,

tmp + 2 * out_width, out_width, out_height, 0, 1,

work + 2 * work_size);

p->emit = EmitRescaledRGB;

WebPInitYUV444Converters();

if (has_alpha) {

WebPRescalerInit(p->scaler_a, io->mb_w, io->mb_h,

tmp + 3 * out_width, out_width, out_height, 0, 1,

work + 3 * work_size);

p->emit_alpha = EmitRescaledAlphaRGB;

if (p->output->colorspace == MODE_RGBA_4444 ||

p->output->colorspace == MODE_rgbA_4444) {

p->emit_alpha_row = ExportAlphaRGBA4444;

} else {

p->emit_alpha_row = ExportAlpha;

}

WebPInitAlphaProcessing();

}

return 1;

}

#endif // WEBP_REDUCE_SIZE

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

// Default custom functions

static int CustomSetup(VP8Io* io) {

WebPDecParams* const p = (WebPDecParams*)io->opaque;

const WEBP_CSP_MODE colorspace = p->output->colorspace;

const int is_rgb = WebPIsRGBMode(colorspace);

const int is_alpha = WebPIsAlphaMode(colorspace);

p->memory = NULL;

p->emit = NULL;

p->emit_alpha = NULL;

p->emit_alpha_row = NULL;

if (!WebPIoInitFromOptions(p->options, io, is_alpha ? MODE_YUV : MODE_YUVA)) {

return 0;

}

if (is_alpha && WebPIsPremultipliedMode(colorspace)) {

WebPInitUpsamplers();

}

if (io->use_scaling) {

#if !defined(WEBP_REDUCE_SIZE)

const int ok = is_rgb ? InitRGBRescaler(io, p) : InitYUVRescaler(io, p);

if (!ok) {

return 0; // memory error

}

#else

return 0; // rescaling support not compiled

#endif

} else {

if (is_rgb) {

WebPInitSamplers();

p->emit = EmitSampledRGB; // default

if (io->fancy_upsampling) {

#ifdef FANCY_UPSAMPLING

const int uv_width = (io->mb_w + 1) >> 1;

p->memory = WebPSafeMalloc(1ULL, (size_t)(io->mb_w + 2 * uv_width));

if (p->memory == NULL) {

return 0; // memory error.

}

p->tmp_y = (uint8_t*)p->memory;

p->tmp_u = p->tmp_y + io->mb_w;

p->tmp_v = p->tmp_u + uv_width;

p->emit = EmitFancyRGB;

WebPInitUpsamplers();

#endif

}

} else {

p->emit = EmitYUV;

}

if (is_alpha) { // need transparency output

p->emit_alpha =

(colorspace == MODE_RGBA_4444 || colorspace == MODE_rgbA_4444) ?

EmitAlphaRGBA4444

: is_rgb ? EmitAlphaRGB

: EmitAlphaYUV;

if (is_rgb) {

WebPInitAlphaProcessing();

}

}

}

return 1;

}

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

static int CustomPut(const VP8Io* io) {

WebPDecParams* const p = (WebPDecParams*)io->opaque;

const int mb_w = io->mb_w;

const int mb_h = io->mb_h;

int num_lines_out;

assert(!(io->mb_y & 1));

if (mb_w <= 0 || mb_h <= 0) {

return 0;

}

num_lines_out = p->emit(io, p);

if (p->emit_alpha != NULL) {

p->emit_alpha(io, p, num_lines_out);

}

p->last_y += num_lines_out;

return 1;

}

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

static void CustomTeardown(const VP8Io* io) {

WebPDecParams* const p = (WebPDecParams*)io->opaque;

WebPSafeFree(p->memory);

p->memory = NULL;

}

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

// Main entry point

void WebPInitCustomIo(WebPDecParams* const params, VP8Io* const io) {

io->put = CustomPut;

io->setup = CustomSetup;

io->teardown = CustomTeardown;

io->opaque = params;

}

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