func ParseBigTIFF(ordr [2]byte, vers uint16, br tiff.BReader, tsp tiff.TagSpace, ftsp tiff.FieldTypeSpace) (out tiff.TIFF, err error) { if tsp == nil { tsp = tiff.DefaultTagSpace } if ftsp == nil { ftsp = tiff.DefaultFieldTypeSpace } var restOfHdr [12]byte if _, err = io.ReadFull(br, restOfHdr[:]); err != nil { return nil, fmt.Errorf("bigtiff: unable to read the rest of the header: %v", err) } offsetSize := br.ByteOrder().Uint16(restOfHdr[:2]) if offsetSize > 8 { return nil, fmt.Errorf("bigtiff: unsupported offset size %d", offsetSize) } // Skip restOfHdr[2:4] since it is a constant that is normally always 0x0000 and has no use yet. firstOffset := br.ByteOrder().Uint64(restOfHdr[4:]) // Check the offset to the first IFD (ensure it is past the end of the header) if firstOffset < 16 { return nil, fmt.Errorf("bigtiff: invalid offset to first IFD, %d < 16", firstOffset) } t := &BigTIFF{ordr: ordr, vers: vers, offsetSize: offsetSize, firstOff: firstOffset, r: br} // Locate and decode IFDs for nextOffset := firstOffset; nextOffset != 0; { var ifd tiff.IFD if ifd, err = ParseIFD(br, nextOffset, tsp, ftsp); err != nil { return nil, err } t.ifds = append(t.ifds, ifd) nextOffset = ifd.NextOffset() } return t, nil }