go*: one go module for the repo, no more nested

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

vendor/github.com/rwcarlsen/goexif/mknote/mknote.go

@@ -0,0 +1,70 @@
+// Package mknote provides makernote parsers that can be used with goexif/exif.
+package mknote
+
+import (
+	"bytes"
+
+	"github.com/rwcarlsen/goexif/exif"
+	"github.com/rwcarlsen/goexif/tiff"
+)
+
+var (
+	// Canon is an exif.Parser for canon makernote data.
+	Canon = &canon{}
+	// NikonV3 is an exif.Parser for nikon makernote data.
+	NikonV3 = &nikonV3{}
+	// All is a list of all available makernote parsers
+	All = []exif.Parser{Canon, NikonV3}
+)
+
+type canon struct{}
+
+// Parse decodes all Canon makernote data found in x and adds it to x.
+func (_ *canon) Parse(x *exif.Exif) error {
+	m, err := x.Get(exif.MakerNote)
+	if err != nil {
+		return nil
+	}
+
+	mk, err := x.Get(exif.Make)
+	if err != nil {
+		return nil
+	}
+
+	if val, err := mk.StringVal(); err != nil || val != "Canon" {
+		return nil
+	}
+
+	// Canon notes are a single IFD directory with no header.
+	// Reader offsets need to be w.r.t. the original tiff structure.
+	buf := bytes.NewReader(append(make([]byte, m.ValOffset), m.Val...))
+	buf.Seek(int64(m.ValOffset), 0)
+
+	mkNotesDir, _, err := tiff.DecodeDir(buf, x.Tiff.Order)
+	if err != nil {
+		return err
+	}
+	x.LoadTags(mkNotesDir, makerNoteCanonFields, false)
+	return nil
+}
+
+type nikonV3 struct{}
+
+// Parse decodes all Nikon makernote data found in x and adds it to x.
+func (_ *nikonV3) Parse(x *exif.Exif) error {
+	m, err := x.Get(exif.MakerNote)
+	if err != nil {
+		return nil
+	} else if bytes.Compare(m.Val[:6], []byte("Nikon\000")) != 0 {
+		return nil
+	}
+
+	// Nikon v3 maker note is a self-contained IFD (offsets are relative
+	// to the start of the maker note)
+	mkNotes, err := tiff.Decode(bytes.NewReader(m.Val[10:]))
+	if err != nil {
+		return err
+	}
+	x.LoadTags(mkNotes.Dirs[0], makerNoteNikon3Fields, false)
+	return nil
+}