mirror of https://github.com/dsoprea/go-exif.git
ifd_enumerate.go: Rename IfdTagEnumerator to byteParser
It's more accurate, and no longer exported.dustin/add_skipped_tags_tracking
Dustin Oprea
parent
5fdad87477
commit
416fd86ecd
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@ -65,56 +65,60 @@ var (
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}
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)
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// IfdTagEnumerator knows how to decode an IFD and all of the tags it
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// byteParser knows how to decode an IFD and all of the tags it
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// describes.
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//
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// The IFDs and the actual values can float throughout the EXIF block, but the
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// IFD itself is just a minor header followed by a set of repeating,
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// statically-sized records. So, the tags (though notnecessarily their values)
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// are fairly simple to enumerate.
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type IfdTagEnumerator struct {
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type byteParser struct {
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byteOrder binary.ByteOrder
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addressableData []byte
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ifdOffset uint32
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buffer *bytes.Buffer
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}
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func NewIfdTagEnumerator(addressableData []byte, byteOrder binary.ByteOrder, ifdOffset uint32) (enumerator *IfdTagEnumerator, err error) {
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func newByteParser(addressableData []byte, byteOrder binary.ByteOrder, ifdOffset uint32) (bp *byteParser, err error) {
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if ifdOffset >= uint32(len(addressableData)) {
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return nil, ErrOffsetInvalid
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}
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enumerator = &IfdTagEnumerator{
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// TODO(dustin): Add test
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bp = &byteParser{
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addressableData: addressableData,
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byteOrder: byteOrder,
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buffer: bytes.NewBuffer(addressableData[ifdOffset:]),
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}
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return enumerator, nil
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return bp, nil
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}
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// getUint16 reads a uint16 and advances both our current and our current
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// accumulator (which allows us to know how far to seek to the beginning of the
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// next IFD when it's time to jump).
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func (ife *IfdTagEnumerator) getUint16() (value uint16, raw []byte, err error) {
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func (bp *byteParser) getUint16() (value uint16, raw []byte, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(error))
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}
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}()
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// TODO(dustin): Add test
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needBytes := 2
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offset := 0
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raw = make([]byte, needBytes)
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for offset < needBytes {
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n, err := ife.buffer.Read(raw[offset:])
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n, err := bp.buffer.Read(raw[offset:])
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log.PanicIf(err)
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offset += n
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}
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value = ife.byteOrder.Uint16(raw)
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value = bp.byteOrder.Uint16(raw)
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return value, raw, nil
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}
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@ -122,25 +126,27 @@ func (ife *IfdTagEnumerator) getUint16() (value uint16, raw []byte, err error) {
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// getUint32 reads a uint32 and advances both our current and our current
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// accumulator (which allows us to know how far to seek to the beginning of the
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// next IFD when it's time to jump).
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func (ife *IfdTagEnumerator) getUint32() (value uint32, raw []byte, err error) {
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func (bp *byteParser) getUint32() (value uint32, raw []byte, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(error))
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}
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}()
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// TODO(dustin): Add test
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needBytes := 4
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offset := 0
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raw = make([]byte, needBytes)
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for offset < needBytes {
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n, err := ife.buffer.Read(raw[offset:])
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n, err := bp.buffer.Read(raw[offset:])
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log.PanicIf(err)
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offset += n
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}
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value = ife.byteOrder.Uint32(raw)
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value = bp.byteOrder.Uint32(raw)
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return value, raw, nil
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}
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@ -163,15 +169,15 @@ func NewIfdEnumerate(ifdMapping *IfdMapping, tagIndex *TagIndex, exifData []byte
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}
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}
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func (ie *IfdEnumerate) getTagEnumerator(ifdOffset uint32) (enumerator *IfdTagEnumerator, err error) {
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func (ie *IfdEnumerate) getByteParser(ifdOffset uint32) (bp *byteParser, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(error))
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}
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}()
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enumerator, err =
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NewIfdTagEnumerator(
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bp, err =
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newByteParser(
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ie.exifData[ExifAddressableAreaStart:],
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ie.byteOrder,
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ifdOffset)
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@ -184,28 +190,28 @@ func (ie *IfdEnumerate) getTagEnumerator(ifdOffset uint32) (enumerator *IfdTagEn
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log.Panic(err)
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}
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return enumerator, nil
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return bp, nil
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}
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func (ie *IfdEnumerate) parseTag(fqIfdPath string, tagPosition int, enumerator *IfdTagEnumerator) (ite *IfdTagEntry, err error) {
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func (ie *IfdEnumerate) parseTag(fqIfdPath string, tagPosition int, bp *byteParser) (ite *IfdTagEntry, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(error))
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}
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}()
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tagId, _, err := enumerator.getUint16()
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tagId, _, err := bp.getUint16()
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log.PanicIf(err)
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tagTypeRaw, _, err := enumerator.getUint16()
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tagTypeRaw, _, err := bp.getUint16()
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log.PanicIf(err)
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tagType := exifcommon.TagTypePrimitive(tagTypeRaw)
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unitCount, _, err := enumerator.getUint32()
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unitCount, _, err := bp.getUint32()
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log.PanicIf(err)
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valueOffset, rawValueOffset, err := enumerator.getUint32()
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valueOffset, rawValueOffset, err := bp.getUint32()
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log.PanicIf(err)
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if tagType.IsValid() == false {
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@ -254,14 +260,14 @@ type TagVisitorFn func(fqIfdPath string, ifdIndex int, ite *IfdTagEntry) (err er
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// ParseIfd decodes the IFD block that we're currently sitting on the first
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// byte of.
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func (ie *IfdEnumerate) ParseIfd(fqIfdPath string, ifdIndex int, enumerator *IfdTagEnumerator, visitor TagVisitorFn, doDescend bool) (nextIfdOffset uint32, entries []*IfdTagEntry, thumbnailData []byte, err error) {
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func (ie *IfdEnumerate) ParseIfd(fqIfdPath string, ifdIndex int, bp *byteParser, visitor TagVisitorFn, doDescend bool) (nextIfdOffset uint32, entries []*IfdTagEntry, thumbnailData []byte, err error) {
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defer func() {
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if state := recover(); state != nil {
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err = log.Wrap(state.(error))
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}
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}()
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tagCount, _, err := enumerator.getUint16()
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tagCount, _, err := bp.getUint16()
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log.PanicIf(err)
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ifdEnumerateLogger.Debugf(nil, "Current IFD tag-count: (%d)", tagCount)
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@ -272,7 +278,7 @@ func (ie *IfdEnumerate) ParseIfd(fqIfdPath string, ifdIndex int, enumerator *Ifd
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var enumeratorThumbnailSize *IfdTagEntry
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for i := 0; i < int(tagCount); i++ {
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ite, err := ie.parseTag(fqIfdPath, i, enumerator)
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ite, err := ie.parseTag(fqIfdPath, i, bp)
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if err != nil {
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if log.Is(err, ErrTagTypeNotValid) == true {
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ifdEnumerateLogger.Warningf(nil, "Tag in IFD [%s] at position (%d) has invalid type (%d) and will be skipped.", fqIfdPath, i, ite.tagType)
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@ -317,7 +323,7 @@ func (ie *IfdEnumerate) ParseIfd(fqIfdPath string, ifdIndex int, enumerator *Ifd
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log.PanicIf(err)
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}
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nextIfdOffset, _, err = enumerator.getUint32()
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nextIfdOffset, _, err = bp.getUint32()
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log.PanicIf(err)
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ifdEnumerateLogger.Debugf(nil, "Next IFD at offset: (%08x)", nextIfdOffset)
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@ -365,7 +371,7 @@ func (ie *IfdEnumerate) scan(fqIfdName string, ifdOffset uint32, visitor TagVisi
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for ifdIndex := 0; ; ifdIndex++ {
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ifdEnumerateLogger.Debugf(nil, "Parsing IFD [%s] (%d) at offset (0x%04x) (scan).", fqIfdName, ifdIndex, ifdOffset)
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enumerator, err := ie.getTagEnumerator(ifdOffset)
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bp, err := ie.getByteParser(ifdOffset)
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if err != nil {
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if err == ErrOffsetInvalid {
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ifdEnumerateLogger.Errorf(nil, nil, "IFD [%s] (%d) at offset (0x%04x) is unreachable. Terminating scan.", fqIfdName, ifdIndex, ifdOffset)
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@ -375,7 +381,7 @@ func (ie *IfdEnumerate) scan(fqIfdName string, ifdOffset uint32, visitor TagVisi
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log.Panic(err)
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}
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nextIfdOffset, _, _, err := ie.ParseIfd(fqIfdName, ifdIndex, enumerator, visitor, true)
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nextIfdOffset, _, _, err := ie.ParseIfd(fqIfdName, ifdIndex, bp, visitor, true)
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log.PanicIf(err)
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if nextIfdOffset == 0 {
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@ -994,7 +1000,7 @@ func (ie *IfdEnumerate) Collect(rootIfdOffset uint32) (index IfdIndex, err error
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ifdEnumerateLogger.Debugf(nil, "Parsing IFD [%s] (%d) at offset (0x%04x) (Collect).", ifdPath, currentIndex, offset)
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enumerator, err := ie.getTagEnumerator(offset)
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bp, err := ie.getByteParser(offset)
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if err != nil {
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if err == ErrOffsetInvalid {
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return index, err
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@ -1003,7 +1009,7 @@ func (ie *IfdEnumerate) Collect(rootIfdOffset uint32) (index IfdIndex, err error
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log.Panic(err)
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}
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nextIfdOffset, entries, thumbnailData, err := ie.ParseIfd(fqIfdPath, currentIndex, enumerator, nil, false)
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nextIfdOffset, entries, thumbnailData, err := ie.ParseIfd(fqIfdPath, currentIndex, bp, nil, false)
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log.PanicIf(err)
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id := len(ifds)
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@ -1169,7 +1175,7 @@ func ParseOneIfd(ifdMapping *IfdMapping, tagIndex *TagIndex, fqIfdPath, ifdPath
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ie := NewIfdEnumerate(ifdMapping, tagIndex, make([]byte, 0), byteOrder)
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enumerator, err := NewIfdTagEnumerator(ifdBlock, byteOrder, 0)
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bp, err := newByteParser(ifdBlock, byteOrder, 0)
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if err != nil {
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if err == ErrOffsetInvalid {
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return 0, nil, err
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@ -1178,7 +1184,7 @@ func ParseOneIfd(ifdMapping *IfdMapping, tagIndex *TagIndex, fqIfdPath, ifdPath
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log.Panic(err)
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}
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nextIfdOffset, entries, _, err = ie.ParseIfd(fqIfdPath, 0, enumerator, visitor, true)
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nextIfdOffset, entries, _, err = ie.ParseIfd(fqIfdPath, 0, bp, visitor, true)
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log.PanicIf(err)
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return nextIfdOffset, entries, nil
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@ -1194,7 +1200,7 @@ func ParseOneTag(ifdMapping *IfdMapping, tagIndex *TagIndex, fqIfdPath, ifdPath
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ie := NewIfdEnumerate(ifdMapping, tagIndex, make([]byte, 0), byteOrder)
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enumerator, err := NewIfdTagEnumerator(tagBlock, byteOrder, 0)
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bp, err := newByteParser(tagBlock, byteOrder, 0)
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if err != nil {
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if err == ErrOffsetInvalid {
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return nil, err
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@ -1203,7 +1209,7 @@ func ParseOneTag(ifdMapping *IfdMapping, tagIndex *TagIndex, fqIfdPath, ifdPath
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log.Panic(err)
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}
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tag, err = ie.parseTag(fqIfdPath, 0, enumerator)
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tag, err = ie.parseTag(fqIfdPath, 0, bp)
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log.PanicIf(err)
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return tag, nil
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