use exif-terminator

vendor/github.com/dsoprea/go-exif/v3/data_layer.go

@@ -0,0 +1,50 @@
+package exif
+
+import (
+	"io"
+
+	"github.com/dsoprea/go-logging"
+	"github.com/dsoprea/go-utility/v2/filesystem"
+)
+
+type ExifBlobSeeker interface {
+	GetReadSeeker(initialOffset int64) (rs io.ReadSeeker, err error)
+}
+
+// ExifReadSeeker knows how to retrieve data from the EXIF blob relative to the
+// beginning of the blob (so, absolute position (0) is the first byte of the
+// EXIF data).
+type ExifReadSeeker struct {
+	rs io.ReadSeeker
+}
+
+func NewExifReadSeeker(rs io.ReadSeeker) *ExifReadSeeker {
+	return &ExifReadSeeker{
+		rs: rs,
+	}
+}
+
+func NewExifReadSeekerWithBytes(exifData []byte) *ExifReadSeeker {
+	sb := rifs.NewSeekableBufferWithBytes(exifData)
+	edbs := NewExifReadSeeker(sb)
+
+	return edbs
+}
+
+// Fork creates a new ReadSeeker instead that wraps a BouncebackReader to
+// maintain its own position in the stream.
+func (edbs *ExifReadSeeker) GetReadSeeker(initialOffset int64) (rs io.ReadSeeker, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	br, err := rifs.NewBouncebackReader(edbs.rs)
+	log.PanicIf(err)
+
+	_, err = br.Seek(initialOffset, io.SeekStart)
+	log.PanicIf(err)
+
+	return br, nil
+}