218 lines
		
	
	
		
			6.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			218 lines
		
	
	
		
			6.9 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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| 
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| #include <stdlib.h>
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| 
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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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| #if defined(__cplusplus) || defined(c_plusplus)
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| extern "C" {
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| #endif
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| 
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| //------------------------------------------------------------------------------
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| // WebPDecBuffer
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| 
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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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| 
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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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| 
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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 uint64_t y_size = (uint64_t)buf->y_stride * height;
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|     const uint64_t u_size = (uint64_t)buf->u_stride * ((height + 1) / 2);
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|     const uint64_t v_size = (uint64_t)buf->v_stride * ((height + 1) / 2);
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|     const uint64_t a_size = (uint64_t)buf->a_stride * height;
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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 &= (buf->y_stride >= width);
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|     ok &= (buf->u_stride >= (width + 1) / 2);
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|     ok &= (buf->v_stride >= (width + 1) / 2);
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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 &= (buf->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 uint64_t size = (uint64_t)buf->stride * height;
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|     ok &= (size <= buf->size);
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|     ok &= (buf->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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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|   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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|       if (options->scaled_width <= 0 || options->scaled_height <= 0) {
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|         return VP8_STATUS_INVALID_PARAM;
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|       }
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|       w = options->scaled_width;
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|       h = options->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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| 
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|   // Then, allocate buffer for real
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|   return AllocateBuffer(out);
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| }
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| 
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| //------------------------------------------------------------------------------
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| // constructors / destructors
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| 
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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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| 
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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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|       free(buffer->private_memory);
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|     buffer->private_memory = NULL;
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|   }
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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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| 
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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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| //------------------------------------------------------------------------------
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| 
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| #if defined(__cplusplus) || defined(c_plusplus)
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| }    // extern "C"
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| #endif
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