261 lines
8.4 KiB
C
261 lines
8.4 KiB
C
// Copyright 2011 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// Everything about WebPDecBuffer
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <stdlib.h>
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#include "./vp8i.h"
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#include "./webpi.h"
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#include "../utils/utils.h"
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//------------------------------------------------------------------------------
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// WebPDecBuffer
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// Number of bytes per pixel for the different color-spaces.
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static const int kModeBpp[MODE_LAST] = {
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3, 4, 3, 4, 4, 2, 2,
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4, 4, 4, 2, // pre-multiplied modes
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1, 1 };
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// Check that webp_csp_mode is within the bounds of WEBP_CSP_MODE.
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// Convert to an integer to handle both the unsigned/signed enum cases
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// without the need for casting to remove type limit warnings.
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static int IsValidColorspace(int webp_csp_mode) {
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return (webp_csp_mode >= MODE_RGB && webp_csp_mode < MODE_LAST);
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}
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// strictly speaking, the very last (or first, if flipped) row
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// doesn't require padding.
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#define MIN_BUFFER_SIZE(WIDTH, HEIGHT, STRIDE) \
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(uint64_t)(STRIDE) * ((HEIGHT) - 1) + (WIDTH)
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static VP8StatusCode CheckDecBuffer(const WebPDecBuffer* const buffer) {
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int ok = 1;
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const WEBP_CSP_MODE mode = buffer->colorspace;
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const int width = buffer->width;
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const int height = buffer->height;
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if (!IsValidColorspace(mode)) {
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ok = 0;
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} else if (!WebPIsRGBMode(mode)) { // YUV checks
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const WebPYUVABuffer* const buf = &buffer->u.YUVA;
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const int uv_width = (width + 1) / 2;
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const int uv_height = (height + 1) / 2;
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const int y_stride = abs(buf->y_stride);
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const int u_stride = abs(buf->u_stride);
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const int v_stride = abs(buf->v_stride);
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const int a_stride = abs(buf->a_stride);
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const uint64_t y_size = MIN_BUFFER_SIZE(width, height, y_stride);
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const uint64_t u_size = MIN_BUFFER_SIZE(uv_width, uv_height, u_stride);
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const uint64_t v_size = MIN_BUFFER_SIZE(uv_width, uv_height, v_stride);
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const uint64_t a_size = MIN_BUFFER_SIZE(width, height, a_stride);
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ok &= (y_size <= buf->y_size);
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ok &= (u_size <= buf->u_size);
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ok &= (v_size <= buf->v_size);
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ok &= (y_stride >= width);
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ok &= (u_stride >= uv_width);
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ok &= (v_stride >= uv_width);
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ok &= (buf->y != NULL);
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ok &= (buf->u != NULL);
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ok &= (buf->v != NULL);
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if (mode == MODE_YUVA) {
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ok &= (a_stride >= width);
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ok &= (a_size <= buf->a_size);
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ok &= (buf->a != NULL);
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}
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} else { // RGB checks
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const WebPRGBABuffer* const buf = &buffer->u.RGBA;
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const int stride = abs(buf->stride);
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const uint64_t size = MIN_BUFFER_SIZE(width, height, stride);
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ok &= (size <= buf->size);
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ok &= (stride >= width * kModeBpp[mode]);
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ok &= (buf->rgba != NULL);
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}
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return ok ? VP8_STATUS_OK : VP8_STATUS_INVALID_PARAM;
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}
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#undef MIN_BUFFER_SIZE
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static VP8StatusCode AllocateBuffer(WebPDecBuffer* const buffer) {
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const int w = buffer->width;
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const int h = buffer->height;
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const WEBP_CSP_MODE mode = buffer->colorspace;
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if (w <= 0 || h <= 0 || !IsValidColorspace(mode)) {
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return VP8_STATUS_INVALID_PARAM;
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}
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if (!buffer->is_external_memory && buffer->private_memory == NULL) {
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uint8_t* output;
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int uv_stride = 0, a_stride = 0;
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uint64_t uv_size = 0, a_size = 0, total_size;
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// We need memory and it hasn't been allocated yet.
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// => initialize output buffer, now that dimensions are known.
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const int stride = w * kModeBpp[mode];
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const uint64_t size = (uint64_t)stride * h;
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if (!WebPIsRGBMode(mode)) {
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uv_stride = (w + 1) / 2;
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uv_size = (uint64_t)uv_stride * ((h + 1) / 2);
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if (mode == MODE_YUVA) {
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a_stride = w;
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a_size = (uint64_t)a_stride * h;
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}
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}
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total_size = size + 2 * uv_size + a_size;
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// Security/sanity checks
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output = (uint8_t*)WebPSafeMalloc(total_size, sizeof(*output));
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if (output == NULL) {
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return VP8_STATUS_OUT_OF_MEMORY;
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}
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buffer->private_memory = output;
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if (!WebPIsRGBMode(mode)) { // YUVA initialization
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WebPYUVABuffer* const buf = &buffer->u.YUVA;
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buf->y = output;
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buf->y_stride = stride;
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buf->y_size = (size_t)size;
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buf->u = output + size;
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buf->u_stride = uv_stride;
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buf->u_size = (size_t)uv_size;
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buf->v = output + size + uv_size;
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buf->v_stride = uv_stride;
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buf->v_size = (size_t)uv_size;
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if (mode == MODE_YUVA) {
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buf->a = output + size + 2 * uv_size;
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}
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buf->a_size = (size_t)a_size;
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buf->a_stride = a_stride;
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} else { // RGBA initialization
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WebPRGBABuffer* const buf = &buffer->u.RGBA;
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buf->rgba = output;
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buf->stride = stride;
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buf->size = (size_t)size;
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}
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}
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return CheckDecBuffer(buffer);
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}
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VP8StatusCode WebPFlipBuffer(WebPDecBuffer* const buffer) {
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if (buffer == NULL) {
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return VP8_STATUS_INVALID_PARAM;
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}
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if (WebPIsRGBMode(buffer->colorspace)) {
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WebPRGBABuffer* const buf = &buffer->u.RGBA;
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buf->rgba += (buffer->height - 1) * buf->stride;
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buf->stride = -buf->stride;
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} else {
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WebPYUVABuffer* const buf = &buffer->u.YUVA;
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const int H = buffer->height;
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buf->y += (H - 1) * buf->y_stride;
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buf->y_stride = -buf->y_stride;
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buf->u += ((H - 1) >> 1) * buf->u_stride;
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buf->u_stride = -buf->u_stride;
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buf->v += ((H - 1) >> 1) * buf->v_stride;
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buf->v_stride = -buf->v_stride;
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if (buf->a != NULL) {
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buf->a += (H - 1) * buf->a_stride;
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buf->a_stride = -buf->a_stride;
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}
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}
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return VP8_STATUS_OK;
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}
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VP8StatusCode WebPAllocateDecBuffer(int w, int h,
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const WebPDecoderOptions* const options,
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WebPDecBuffer* const out) {
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VP8StatusCode status;
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if (out == NULL || w <= 0 || h <= 0) {
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return VP8_STATUS_INVALID_PARAM;
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}
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if (options != NULL) { // First, apply options if there is any.
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if (options->use_cropping) {
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const int cw = options->crop_width;
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const int ch = options->crop_height;
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const int x = options->crop_left & ~1;
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const int y = options->crop_top & ~1;
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if (x < 0 || y < 0 || cw <= 0 || ch <= 0 || x + cw > w || y + ch > h) {
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return VP8_STATUS_INVALID_PARAM; // out of frame boundary.
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}
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w = cw;
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h = ch;
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}
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if (options->use_scaling) {
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int scaled_width = options->scaled_width;
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int scaled_height = options->scaled_height;
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if (!WebPRescalerGetScaledDimensions(
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w, h, &scaled_width, &scaled_height)) {
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return VP8_STATUS_INVALID_PARAM;
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}
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w = scaled_width;
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h = scaled_height;
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}
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}
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out->width = w;
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out->height = h;
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// Then, allocate buffer for real.
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status = AllocateBuffer(out);
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if (status != VP8_STATUS_OK) return status;
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// Use the stride trick if vertical flip is needed.
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if (options != NULL && options->flip) {
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status = WebPFlipBuffer(out);
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}
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return status;
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}
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//------------------------------------------------------------------------------
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// constructors / destructors
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int WebPInitDecBufferInternal(WebPDecBuffer* buffer, int version) {
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if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) {
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return 0; // version mismatch
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}
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if (buffer == NULL) return 0;
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memset(buffer, 0, sizeof(*buffer));
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return 1;
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}
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void WebPFreeDecBuffer(WebPDecBuffer* buffer) {
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if (buffer != NULL) {
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if (!buffer->is_external_memory) {
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WebPSafeFree(buffer->private_memory);
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}
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buffer->private_memory = NULL;
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}
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}
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void WebPCopyDecBuffer(const WebPDecBuffer* const src,
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WebPDecBuffer* const dst) {
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if (src != NULL && dst != NULL) {
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*dst = *src;
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if (src->private_memory != NULL) {
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dst->is_external_memory = 1; // dst buffer doesn't own the memory.
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dst->private_memory = NULL;
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}
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}
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}
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// Copy and transfer ownership from src to dst (beware of parameter order!)
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void WebPGrabDecBuffer(WebPDecBuffer* const src, WebPDecBuffer* const dst) {
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if (src != NULL && dst != NULL) {
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*dst = *src;
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if (src->private_memory != NULL) {
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src->is_external_memory = 1; // src relinquishes ownership
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src->private_memory = NULL;
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}
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}
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}
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//------------------------------------------------------------------------------
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