1 files changed, 416 insertions, 0 deletions
diff --git a/vendor/github.com/superseriousbusiness/go-jpeg-image-structure/v2/segment_list.go b/vendor/github.com/superseriousbusiness/go-jpeg-image-structure/v2/segment_list.go
new file mode 100644
index 000000000..b4f4d5810
--- /dev/null
+++ b/vendor/github.com/superseriousbusiness/go-jpeg-image-structure/v2/segment_list.go
@@ -0,0 +1,416 @@
+package jpegstructure
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	"crypto/sha1"
+	"encoding/binary"
+
+	"github.com/dsoprea/go-exif/v3"
+	"github.com/dsoprea/go-exif/v3/common"
+	"github.com/dsoprea/go-iptc"
+	"github.com/dsoprea/go-logging"
+)
+
+// SegmentList contains a slice of segments.
+type SegmentList struct {
+	segments []*Segment
+}
+
+// NewSegmentList returns a new SegmentList struct.
+func NewSegmentList(segments []*Segment) (sl *SegmentList) {
+	if segments == nil {
+		segments = make([]*Segment, 0)
+	}
+
+	return &SegmentList{
+		segments: segments,
+	}
+}
+
+// OffsetsEqual returns true is all segments have the same marker-IDs and were
+// found at the same offsets.
+func (sl *SegmentList) OffsetsEqual(o *SegmentList) bool {
+	if len(o.segments) != len(sl.segments) {
+		return false
+	}
+
+	for i, s := range o.segments {
+		if s.MarkerId != sl.segments[i].MarkerId || s.Offset != sl.segments[i].Offset {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Segments returns the underlying slice of segments.
+func (sl *SegmentList) Segments() []*Segment {
+	return sl.segments
+}
+
+// Add adds another segment.
+func (sl *SegmentList) Add(s *Segment) {
+	sl.segments = append(sl.segments, s)
+}
+
+// Print prints segment info.
+func (sl *SegmentList) Print() {
+	if len(sl.segments) == 0 {
+		fmt.Printf("No segments.\n")
+	} else {
+		exifIndex, _, err := sl.FindExif()
+		if err != nil {
+			if err == exif.ErrNoExif {
+				exifIndex = -1
+			} else {
+				log.Panic(err)
+			}
+		}
+
+		xmpIndex, _, err := sl.FindXmp()
+		if err != nil {
+			if err == ErrNoXmp {
+				xmpIndex = -1
+			} else {
+				log.Panic(err)
+			}
+		}
+
+		iptcIndex, _, err := sl.FindIptc()
+		if err != nil {
+			if err == ErrNoIptc {
+				iptcIndex = -1
+			} else {
+				log.Panic(err)
+			}
+		}
+
+		for i, s := range sl.segments {
+			fmt.Printf("%2d: %s", i, s.EmbeddedString())
+
+			if i == exifIndex {
+				fmt.Printf(" [EXIF]")
+			} else if i == xmpIndex {
+				fmt.Printf(" [XMP]")
+			} else if i == iptcIndex {
+				fmt.Printf(" [IPTC]")
+			}
+
+			fmt.Printf("\n")
+		}
+	}
+}
+
+// Validate checks that all of the markers are actually located at all of the
+// recorded offsets.
+func (sl *SegmentList) Validate(data []byte) (err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	if len(sl.segments) < 2 {
+		log.Panicf("minimum segments not found")
+	}
+
+	if sl.segments[0].MarkerId != MARKER_SOI {
+		log.Panicf("first segment not SOI")
+	} else if sl.segments[len(sl.segments)-1].MarkerId != MARKER_EOI {
+		log.Panicf("last segment not EOI")
+	}
+
+	lastOffset := 0
+	for i, s := range sl.segments {
+		if lastOffset != 0 && s.Offset <= lastOffset {
+			log.Panicf("segment offset not greater than the last: SEGMENT=(%d) (0x%08x) <= (0x%08x)", i, s.Offset, lastOffset)
+		}
+
+		// The scan-data doesn't start with a marker.
+		if s.MarkerId == 0x0 {
+			continue
+		}
+
+		o := s.Offset
+		if bytes.Compare(data[o:o+2], []byte{0xff, s.MarkerId}) != 0 {
+			log.Panicf("segment offset does not point to the start of a segment: SEGMENT=(%d) (0x%08x)", i, s.Offset)
+		}
+
+		lastOffset = o
+	}
+
+	return nil
+}
+
+// FindExif returns the the segment that hosts the EXIF data (if present).
+func (sl *SegmentList) FindExif() (index int, segment *Segment, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	for i, s := range sl.segments {
+		if s.IsExif() == true {
+			return i, s, nil
+		}
+	}
+
+	return -1, nil, exif.ErrNoExif
+}
+
+// FindXmp returns the the segment that hosts the XMP data (if present).
+func (sl *SegmentList) FindXmp() (index int, segment *Segment, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	for i, s := range sl.segments {
+		if s.IsXmp() == true {
+			return i, s, nil
+		}
+	}
+
+	return -1, nil, ErrNoXmp
+}
+
+// FindIptc returns the the segment that hosts the IPTC data (if present).
+func (sl *SegmentList) FindIptc() (index int, segment *Segment, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	for i, s := range sl.segments {
+		if s.IsIptc() == true {
+			return i, s, nil
+		}
+	}
+
+	return -1, nil, ErrNoIptc
+}
+
+// Exif returns an `exif.Ifd` instance for the EXIF data we currently have.
+func (sl *SegmentList) Exif() (rootIfd *exif.Ifd, rawExif []byte, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	_, s, err := sl.FindExif()
+	log.PanicIf(err)
+
+	rootIfd, rawExif, err = s.Exif()
+	log.PanicIf(err)
+
+	return rootIfd, rawExif, nil
+}
+
+// Iptc returns embedded IPTC data if present.
+func (sl *SegmentList) Iptc() (tags map[iptc.StreamTagKey][]iptc.TagData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	// TODO(dustin): Add comment and return data.
+
+	_, s, err := sl.FindIptc()
+	log.PanicIf(err)
+
+	tags, err = s.Iptc()
+	log.PanicIf(err)
+
+	return tags, nil
+}
+
+// ConstructExifBuilder returns an `exif.IfdBuilder` instance (needed for
+// modifying) preloaded with all existing tags.
+func (sl *SegmentList) ConstructExifBuilder() (rootIb *exif.IfdBuilder, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	rootIfd, _, err := sl.Exif()
+	if log.Is(err, exif.ErrNoExif) == true {
+		// No EXIF. Just create a boilerplate builder.
+
+		im := exifcommon.NewIfdMapping()
+
+		err := exifcommon.LoadStandardIfds(im)
+		log.PanicIf(err)
+
+		ti := exif.NewTagIndex()
+
+		rootIb :=
+			exif.NewIfdBuilder(
+				im,
+				ti,
+				exifcommon.IfdStandardIfdIdentity,
+				exifcommon.EncodeDefaultByteOrder)
+
+		return rootIb, nil
+	} else if err != nil {
+		log.Panic(err)
+	}
+
+	rootIb = exif.NewIfdBuilderFromExistingChain(rootIfd)
+
+	return rootIb, nil
+}
+
+// DumpExif returns an unstructured list of tags (useful when just reviewing).
+func (sl *SegmentList) DumpExif() (segmentIndex int, segment *Segment, exifTags []exif.ExifTag, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	segmentIndex, s, err := sl.FindExif()
+	if err != nil {
+		if err == exif.ErrNoExif {
+			return 0, nil, nil, err
+		}
+
+		log.Panic(err)
+	}
+
+	exifTags, err = s.FlatExif()
+	log.PanicIf(err)
+
+	return segmentIndex, s, exifTags, nil
+}
+
+func makeEmptyExifSegment() (s *Segment) {
+
+	// TODO(dustin): Add test
+
+	return &Segment{
+		MarkerId: MARKER_APP1,
+	}
+}
+
+// SetExif encodes and sets EXIF data into the given segment. If `index` is -1,
+// append a new segment.
+func (sl *SegmentList) SetExif(ib *exif.IfdBuilder) (err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	_, s, err := sl.FindExif()
+	if err != nil {
+		if log.Is(err, exif.ErrNoExif) == false {
+			log.Panic(err)
+		}
+
+		s = makeEmptyExifSegment()
+
+		prefix := sl.segments[:1]
+
+		// Install it near the beginning where we know it's safe. We can't
+		// insert it after the EOI segment, and there might be more than one
+		// depending on implementation and/or lax adherence to the standard.
+		tail := append([]*Segment{s}, sl.segments[1:]...)
+
+		sl.segments = append(prefix, tail...)
+	}
+
+	err = s.SetExif(ib)
+	log.PanicIf(err)
+
+	return nil
+}
+
+// DropExif will drop the EXIF data if present.
+func (sl *SegmentList) DropExif() (wasDropped bool, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	// TODO(dustin): Add test
+
+	i, _, err := sl.FindExif()
+	if err == nil {
+		// Found.
+		sl.segments = append(sl.segments[:i], sl.segments[i+1:]...)
+
+		return true, nil
+	} else if log.Is(err, exif.ErrNoExif) == false {
+		log.Panic(err)
+	}
+
+	// Not found.
+	return false, nil
+}
+
+// Write writes the segment data to the given `io.Writer`.
+func (sl *SegmentList) Write(w io.Writer) (err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	offset := 0
+
+	for i, s := range sl.segments {
+		h := sha1.New()
+		h.Write(s.Data)
+
+		// The scan-data will have a marker-ID of (0) because it doesn't have a
+		// marker-ID or length.
+		if s.MarkerId != 0 {
+			_, err := w.Write([]byte{0xff})
+			log.PanicIf(err)
+
+			offset++
+
+			_, err = w.Write([]byte{s.MarkerId})
+			log.PanicIf(err)
+
+			offset++
+
+			sizeLen, found := markerLen[s.MarkerId]
+			if found == false || sizeLen == 2 {
+				sizeLen = 2
+				l := uint16(len(s.Data) + sizeLen)
+
+				err = binary.Write(w, binary.BigEndian, &l)
+				log.PanicIf(err)
+
+				offset += 2
+			} else if sizeLen == 4 {
+				l := uint32(len(s.Data) + sizeLen)
+
+				err = binary.Write(w, binary.BigEndian, &l)
+				log.PanicIf(err)
+
+				offset += 4
+			} else if sizeLen != 0 {
+				log.Panicf("not a supported marker-size: SEGMENT-INDEX=(%d) MARKER-ID=(0x%02x) MARKER-SIZE-LEN=(%d)", i, s.MarkerId, sizeLen)
+			}
+		}
+
+		_, err := w.Write(s.Data)
+		log.PanicIf(err)
+
+		offset += len(s.Data)
+	}
+
+	return nil
+}