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Diffstat (limited to 'thirdparty/libwebp/dec/io_dec.c')
| -rw-r--r-- | thirdparty/libwebp/dec/io_dec.c | 645 |
1 files changed, 645 insertions, 0 deletions
diff --git a/thirdparty/libwebp/dec/io_dec.c b/thirdparty/libwebp/dec/io_dec.c new file mode 100644 index 0000000000..8bfab86959 --- /dev/null +++ b/thirdparty/libwebp/dec/io_dec.c @@ -0,0 +1,645 @@ +// 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 "../dec/vp8i_dec.h" +#include "./webpi_dec.h" +#include "../dsp/dsp.h" +#include "../dsp/yuv.h" +#include "../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; +#ifdef WEBP_SWAP_16BIT_CSP + 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) + +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; +#ifdef WEBP_SWAP_16BIT_CSP + 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; +} + +//------------------------------------------------------------------------------ +// 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) { + const int ok = is_rgb ? InitRGBRescaler(io, p) : InitYUVRescaler(io, p); + if (!ok) { + return 0; // memory error + } + } 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(); + } + } + } + + if (is_rgb) { + VP8YUVInit(); + } + 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; +} + +//------------------------------------------------------------------------------ |