func ParseIFD(br tiff.BReader, offset uint64, tsp tiff.TagSpace, ftsp tiff.FieldTypeSpace) (out tiff.IFD, err error) { if br == nil { return nil, errors.New("tiff: no BReader supplied") } if ftsp == nil { ftsp = tiff.DefaultFieldTypeSpace } if tsp == nil { tsp = tiff.DefaultTagSpace } ifd := &imageFileDirectory{ fieldMap: make(map[uint16]tiff.Field, 1), } br.Seek(int64(offset), 0) if err = br.BRead(&ifd.numEntries); err != nil { err = fmt.Errorf("bigtiff: unable to read the number of entries for the IFD at offset %#08x: %v", offset, err) return } for i := uint64(0); i < ifd.numEntries; i++ { var f tiff.Field if f, err = ParseField(br, tsp, ftsp); err != nil { return } ifd.fields = append(ifd.fields, f) ifd.fieldMap[f.Tag().ID()] = f } if err = br.BRead(&ifd.nextOffset); err != nil { err = fmt.Errorf("bigtiff: unable to read the offset for the next ifd: %v", err) return } return ifd, nil }