1 files changed, 273 insertions, 0 deletions
diff --git a/vendor/github.com/dsoprea/go-exif/v3/common/value_encoder.go b/vendor/github.com/dsoprea/go-exif/v3/common/value_encoder.go
new file mode 100644
index 000000000..2cd26cc7b
--- /dev/null
+++ b/vendor/github.com/dsoprea/go-exif/v3/common/value_encoder.go
@@ -0,0 +1,273 @@
+package exifcommon
+
+import (
+	"bytes"
+	"math"
+	"reflect"
+	"time"
+
+	"encoding/binary"
+
+	"github.com/dsoprea/go-logging"
+)
+
+var (
+	typeEncodeLogger = log.NewLogger("exif.type_encode")
+)
+
+// EncodedData encapsulates the compound output of an encoding operation.
+type EncodedData struct {
+	Type    TagTypePrimitive
+	Encoded []byte
+
+	// TODO(dustin): Is this really necessary? We might have this just to correlate to the incoming stream format (raw bytes and a unit-count both for incoming and outgoing).
+	UnitCount uint32
+}
+
+// ValueEncoder knows how to encode values of every type to bytes.
+type ValueEncoder struct {
+	byteOrder binary.ByteOrder
+}
+
+// NewValueEncoder returns a new ValueEncoder.
+func NewValueEncoder(byteOrder binary.ByteOrder) *ValueEncoder {
+	return &ValueEncoder{
+		byteOrder: byteOrder,
+	}
+}
+
+func (ve *ValueEncoder) encodeBytes(value []uint8) (ed EncodedData, err error) {
+	ed.Type = TypeByte
+	ed.Encoded = []byte(value)
+	ed.UnitCount = uint32(len(value))
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeAscii(value string) (ed EncodedData, err error) {
+	ed.Type = TypeAscii
+
+	ed.Encoded = []byte(value)
+	ed.Encoded = append(ed.Encoded, 0)
+
+	ed.UnitCount = uint32(len(ed.Encoded))
+
+	return ed, nil
+}
+
+// encodeAsciiNoNul returns a string encoded as a byte-string without a trailing
+// NUL byte.
+//
+// Note that:
+//
+// 1. This type can not be automatically encoded using `Encode()`. The default
+//    mode is to encode *with* a trailing NUL byte using `encodeAscii`. Only
+//    certain undefined-type tags using an unterminated ASCII string and these
+//    are exceptional in nature.
+//
+// 2. The presence of this method allows us to completely test the complimentary
+//    no-nul parser.
+//
+func (ve *ValueEncoder) encodeAsciiNoNul(value string) (ed EncodedData, err error) {
+	ed.Type = TypeAsciiNoNul
+	ed.Encoded = []byte(value)
+	ed.UnitCount = uint32(len(ed.Encoded))
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeShorts(value []uint16) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+	ed.Encoded = make([]byte, ed.UnitCount*2)
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		ve.byteOrder.PutUint16(ed.Encoded[i*2:(i+1)*2], value[i])
+	}
+
+	ed.Type = TypeShort
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeLongs(value []uint32) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+	ed.Encoded = make([]byte, ed.UnitCount*4)
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		ve.byteOrder.PutUint32(ed.Encoded[i*4:(i+1)*4], value[i])
+	}
+
+	ed.Type = TypeLong
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeFloats(value []float32) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+	ed.Encoded = make([]byte, ed.UnitCount*4)
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		ve.byteOrder.PutUint32(ed.Encoded[i*4:(i+1)*4], math.Float32bits(value[i]))
+	}
+
+	ed.Type = TypeFloat
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeDoubles(value []float64) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+	ed.Encoded = make([]byte, ed.UnitCount*8)
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		ve.byteOrder.PutUint64(ed.Encoded[i*8:(i+1)*8], math.Float64bits(value[i]))
+	}
+
+	ed.Type = TypeDouble
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeRationals(value []Rational) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+	ed.Encoded = make([]byte, ed.UnitCount*8)
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		ve.byteOrder.PutUint32(ed.Encoded[i*8+0:i*8+4], value[i].Numerator)
+		ve.byteOrder.PutUint32(ed.Encoded[i*8+4:i*8+8], value[i].Denominator)
+	}
+
+	ed.Type = TypeRational
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeSignedLongs(value []int32) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+
+	b := bytes.NewBuffer(make([]byte, 0, 8*ed.UnitCount))
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		err := binary.Write(b, ve.byteOrder, value[i])
+		log.PanicIf(err)
+	}
+
+	ed.Type = TypeSignedLong
+	ed.Encoded = b.Bytes()
+
+	return ed, nil
+}
+
+func (ve *ValueEncoder) encodeSignedRationals(value []SignedRational) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	ed.UnitCount = uint32(len(value))
+
+	b := bytes.NewBuffer(make([]byte, 0, 8*ed.UnitCount))
+
+	for i := uint32(0); i < ed.UnitCount; i++ {
+		err := binary.Write(b, ve.byteOrder, value[i].Numerator)
+		log.PanicIf(err)
+
+		err = binary.Write(b, ve.byteOrder, value[i].Denominator)
+		log.PanicIf(err)
+	}
+
+	ed.Type = TypeSignedRational
+	ed.Encoded = b.Bytes()
+
+	return ed, nil
+}
+
+// Encode returns bytes for the given value, infering type from the actual
+// value. This does not support `TypeAsciiNoNull` (all strings are encoded as
+// `TypeAscii`).
+func (ve *ValueEncoder) Encode(value interface{}) (ed EncodedData, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+		}
+	}()
+
+	switch t := value.(type) {
+	case []byte:
+		ed, err = ve.encodeBytes(t)
+		log.PanicIf(err)
+	case string:
+		ed, err = ve.encodeAscii(t)
+		log.PanicIf(err)
+	case []uint16:
+		ed, err = ve.encodeShorts(t)
+		log.PanicIf(err)
+	case []uint32:
+		ed, err = ve.encodeLongs(t)
+		log.PanicIf(err)
+	case []float32:
+		ed, err = ve.encodeFloats(t)
+		log.PanicIf(err)
+	case []float64:
+		ed, err = ve.encodeDoubles(t)
+		log.PanicIf(err)
+	case []Rational:
+		ed, err = ve.encodeRationals(t)
+		log.PanicIf(err)
+	case []int32:
+		ed, err = ve.encodeSignedLongs(t)
+		log.PanicIf(err)
+	case []SignedRational:
+		ed, err = ve.encodeSignedRationals(t)
+		log.PanicIf(err)
+	case time.Time:
+		// For convenience, if the user doesn't want to deal with translation
+		// semantics with timestamps.
+
+		s := ExifFullTimestampString(t)
+
+		ed, err = ve.encodeAscii(s)
+		log.PanicIf(err)
+	default:
+		log.Panicf("value not encodable: [%s] [%v]", reflect.TypeOf(value), value)
+	}
+
+	return ed, nil
+}