Method readMetadata

src/webpimage.cpp:472–495

/* =========================================== */

void WebPImage::readMetadata() {
  if (io_->open() != 0)
    throw Error(ErrorCode::kerDataSourceOpenFailed, io_->path(), strError());
  IoCloser closer(*io_);
  // Ensure that this is the correct image type
  if (!isWebPType(*io_, true)) {
    if (io_->error() || io_->eof())
      throw Error(ErrorCode::kerFailedToReadImageData);
    throw Error(ErrorCode::kerNotAJpeg);
  }
  clearMetadata();

  byte data[12];
  DataBuf chunkId(5);
  chunkId.write_uint8(4, '\0');

  io_->readOrThrow(data, WEBP_TAG_SIZE * 3, Exiv2::ErrorCode::kerCorruptedMetadata);

  const uint32_t filesize = Safe::add(Exiv2::getULong(data + WEBP_TAG_SIZE, littleEndian), 8U);
  Internal::enforce(filesize <= io_->size(), Exiv2::ErrorCode::kerCorruptedMetadata);

  WebPImage::decodeChunks(filesize);

}  // WebPImage::readMetadata

void WebPImage::decodeChunks(uint32_t filesize) {
  DataBuf chunkId(5);