Method parseHeader

src/librawspeed/decoders/MrwDecoder.cpp:49–152

}

void MrwDecoder::parseHeader() {
  if (!isMRW(mFile))
    ThrowRDE("This isn't actually a MRW file, why are you calling me?");

  const DataBuffer db(*mFile, Endianness::big);
  ByteStream bs(db);

  // magic
  bs.skipBytes(4);

  // the size of the rest of the header, up to the image data
  const auto headerSize = bs.getU32();
  bs.check(headerSize);

  // ... and offset to the image data at the same time
  const auto dataOffset = bs.getPosition() + headerSize;
  assert(bs.getPosition() == 8);

  // now, let's parse rest of the header.
  bs = bs.getSubStream(0, dataOffset);
  bs.skipBytes(8);

  bool foundPRD = false;
  while (bs.getRemainSize() > 0) {
    uint32_t tag = bs.getU32();
    uint32_t len = bs.getU32();
    bs.check(len);
    if (!len)
      ThrowRDE("Found entry of zero length, MRW is corrupt.");

    const auto origPos = bs.getPosition();

    switch (tag) {
    case 0x505244: {            // PRD
      foundPRD = true;
      bs.skipBytes(8);          // Version Number
      raw_height = bs.getU16(); // CCD Size Y
      raw_width = bs.getU16();  // CCD Size X

      if (!raw_width || !raw_height || raw_width > 3280 || raw_height > 2456) {
        ThrowRDE("Unexpected image dimensions found: (%u; %u)", raw_width,
                 raw_height);
      }

      bs.skipBytes(2);          // Image Size Y
      bs.skipBytes(2);          // Image Size X

      bpp = bs.getByte(); // DataSize
      if (12 != bpp && 16 != bpp)
        ThrowRDE("Unknown data size");

      if ((raw_height * raw_width * bpp) % 8 != 0)
        ThrowRDE("Bad combination of image size and raw dimensions.");

      if (12 != bs.getByte()) // PixelSize
        ThrowRDE("Unexpected pixel size");

      const auto SM = bs.getByte(); // StorageMethod