// Main flow
static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
                                WebPDecParams* const params) {
  VP8StatusCode status;
  VP8Io io;
  WebPHeaderStructure headers;

  headers.data = data;
  headers.data_size = data_size;
  status = WebPParseHeaders(&headers);   // Process Pre-VP8 chunks.
  if (status != VP8_STATUS_OK) {
    return status;
  }

  assert(params != NULL);
  VP8InitIo(&io);
  io.data = headers.data + headers.offset;
  io.data_size = headers.data_size - headers.offset;
  WebPInitCustomIo(params, &io);  // Plug the I/O functions.

  if (!headers.is_lossless) {
    VP8Decoder* const dec = VP8New();
    if (dec == NULL) {
      return VP8_STATUS_OUT_OF_MEMORY;
    }
#ifdef WEBP_USE_THREAD
    dec->use_threads_ = params->options && (params->options->use_threads > 0);
#else
    dec->use_threads_ = 0;
#endif
    dec->alpha_data_ = headers.alpha_data;
    dec->alpha_data_size_ = headers.alpha_data_size;

    // Decode bitstream header, update io->width/io->height.
    if (!VP8GetHeaders(dec, &io)) {
      status = dec->status_;   // An error occurred. Grab error status.
    } else {
      // Allocate/check output buffers.
      status = WebPAllocateDecBuffer(io.width, io.height, params->options,
                                     params->output);
      if (status == VP8_STATUS_OK) {  // Decode
        if (!VP8Decode(dec, &io)) {
          status = dec->status_;
        }
      }
    }
    VP8Delete(dec);
  } else {
    VP8LDecoder* const dec = VP8LNew();
    if (dec == NULL) {
      return VP8_STATUS_OUT_OF_MEMORY;
    }
    if (!VP8LDecodeHeader(dec, &io)) {
      status = dec->status_;   // An error occurred. Grab error status.
    } else {
      // Allocate/check output buffers.
      status = WebPAllocateDecBuffer(io.width, io.height, params->options,
                                     params->output);
      if (status == VP8_STATUS_OK) {  // Decode
        if (!VP8LDecodeImage(dec)) {
          status = dec->status_;
        }
      }
    }
    VP8LDelete(dec);
  }

  if (status != VP8_STATUS_OK) {
    WebPFreeDecBuffer(params->output);
  }
  return status;
}
示例#2
0
文件: webp.c 项目: ZW19911104/libwebp
// Main flow
static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
                                WebPDecParams* const params) {
  VP8StatusCode status;
  VP8Io io;
  WebPHeaderStructure headers;

  headers.data = data;
  headers.data_size = data_size;
  headers.have_all_data = 1;
  status = WebPParseHeaders(&headers);   // Process Pre-VP8 chunks.
  if (status != VP8_STATUS_OK) {
    return status;
  }

  assert(params != NULL);
  VP8InitIo(&io);
  io.data = headers.data + headers.offset;
  io.data_size = headers.data_size - headers.offset;
  WebPInitCustomIo(params, &io);  // Plug the I/O functions.

  if (!headers.is_lossless) {
    VP8Decoder* const dec = VP8New();
    if (dec == NULL) {
      return VP8_STATUS_OUT_OF_MEMORY;
    }
    dec->alpha_data_ = headers.alpha_data;
    dec->alpha_data_size_ = headers.alpha_data_size;

    // Decode bitstream header, update io->width/io->height.
    if (!VP8GetHeaders(dec, &io)) {
      status = dec->status_;   // An error occurred. Grab error status.
    } else {
      // Allocate/check output buffers.
      status = WebPAllocateDecBuffer(io.width, io.height, params->options,
                                     params->output);
      if (status == VP8_STATUS_OK) {  // Decode
        // This change must be done before calling VP8Decode()
        dec->mt_method_ = VP8GetThreadMethod(params->options, &headers,
                                             io.width, io.height);
        VP8InitDithering(params->options, dec);
        if (!VP8Decode(dec, &io)) {
          status = dec->status_;
        }
      }
    }
    VP8Delete(dec);
  } else {
    VP8LDecoder* const dec = VP8LNew();
    if (dec == NULL) {
      return VP8_STATUS_OUT_OF_MEMORY;
    }
    if (!VP8LDecodeHeader(dec, &io)) {
      status = dec->status_;   // An error occurred. Grab error status.
    } else {
      // Allocate/check output buffers.
      status = WebPAllocateDecBuffer(io.width, io.height, params->options,
                                     params->output);
      if (status == VP8_STATUS_OK) {  // Decode
        if (!VP8LDecodeImage(dec)) {
          status = dec->status_;
        }
      }
    }
    VP8LDelete(dec);
  }

  if (status != VP8_STATUS_OK) {
    WebPFreeDecBuffer(params->output);
  } else {
    if (params->options != NULL && params->options->flip) {
      // This restores the original stride values if options->flip was used
      // during the call to WebPAllocateDecBuffer above.
      status = WebPFlipBuffer(params->output);
    }
  }
  return status;
}
示例#3
0
static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
                                WebPDecParams* const params) {
  VP8StatusCode status;
  VP8Io io;
  WebPHeaderStructure headers;

  headers.data = data;
  headers.data_size = data_size;
  status = WebPParseHeaders(&headers);   
  if (status != VP8_STATUS_OK) {
    return status;
  }

  assert(params != NULL);
  VP8InitIo(&io);
  io.data = headers.data + headers.offset;
  io.data_size = headers.data_size - headers.offset;
  WebPInitCustomIo(params, &io);  

  if (!headers.is_lossless) {
    VP8Decoder* const dec = VP8New();
    if (dec == NULL) {
      return VP8_STATUS_OUT_OF_MEMORY;
    }
#ifdef WEBP_USE_THREAD
    dec->use_threads_ = params->options && (params->options->use_threads > 0);
#else
    dec->use_threads_ = 0;
#endif
    dec->alpha_data_ = headers.alpha_data;
    dec->alpha_data_size_ = headers.alpha_data_size;

    
    if (!VP8GetHeaders(dec, &io)) {
      status = dec->status_;   
    } else {
      
      status = WebPAllocateDecBuffer(io.width, io.height, params->options,
                                     params->output);
      if (status == VP8_STATUS_OK) {  
        if (!VP8Decode(dec, &io)) {
          status = dec->status_;
        }
      }
    }
    VP8Delete(dec);
  } else {
    VP8LDecoder* const dec = VP8LNew();
    if (dec == NULL) {
      return VP8_STATUS_OUT_OF_MEMORY;
    }
    if (!VP8LDecodeHeader(dec, &io)) {
      status = dec->status_;   
    } else {
      
      status = WebPAllocateDecBuffer(io.width, io.height, params->options,
                                     params->output);
      if (status == VP8_STATUS_OK) {  
        if (!VP8LDecodeImage(dec)) {
          status = dec->status_;
        }
      }
    }
    VP8LDelete(dec);
  }

  if (status != VP8_STATUS_OK) {
    WebPFreeDecBuffer(params->output);
  }
  return status;
}