1 files changed, 155 insertions, 0 deletions
diff --git a/vendor/github.com/abema/go-mp4/box_info.go b/vendor/github.com/abema/go-mp4/box_info.go
new file mode 100644
index 000000000..b5c587fd9
--- /dev/null
+++ b/vendor/github.com/abema/go-mp4/box_info.go
@@ -0,0 +1,155 @@
+package mp4
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"math"
+)
+
+type Context struct {
+	// IsQuickTimeCompatible represents whether ftyp.compatible_brands contains "qt  ".
+	IsQuickTimeCompatible bool
+
+	// UnderWave represents whether current box is under the wave box.
+	UnderWave bool
+
+	// UnderIlst represents whether current box is under the ilst box.
+	UnderIlst bool
+
+	// UnderIlstMeta represents whether current box is under the metadata box under the ilst box.
+	UnderIlstMeta bool
+
+	// UnderIlstFreeMeta represents whether current box is under "----" box.
+	UnderIlstFreeMeta bool
+
+	// UnderUdta represents whether current box is under the udta box.
+	UnderUdta bool
+}
+
+// BoxInfo has common infomations of box
+type BoxInfo struct {
+	// Offset specifies an offset of the box in a file.
+	Offset uint64
+
+	// Size specifies size(bytes) of box.
+	Size uint64
+
+	// HeaderSize specifies size(bytes) of common fields which are defined as "Box" class member at ISO/IEC 14496-12.
+	HeaderSize uint64
+
+	// Type specifies box type which is represented by 4 characters.
+	Type BoxType
+
+	// ExtendToEOF is set true when Box.size is zero. It means that end of box equals to end of file.
+	ExtendToEOF bool
+
+	// Context would be set by ReadBoxStructure, not ReadBoxInfo.
+	Context
+}
+
+func (bi *BoxInfo) IsSupportedType() bool {
+	return bi.Type.IsSupported(bi.Context)
+}
+
+const (
+	SmallHeaderSize = 8
+	LargeHeaderSize = 16
+)
+
+// WriteBoxInfo writes common fields which are defined as "Box" class member at ISO/IEC 14496-12.
+// This function ignores bi.Offset and returns BoxInfo which contains real Offset and recalculated Size/HeaderSize.
+func WriteBoxInfo(w io.WriteSeeker, bi *BoxInfo) (*BoxInfo, error) {
+	offset, err := w.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return nil, err
+	}
+
+	var data []byte
+	if bi.ExtendToEOF {
+		data = make([]byte, SmallHeaderSize)
+	} else if bi.Size <= math.MaxUint32 && bi.HeaderSize != LargeHeaderSize {
+		data = make([]byte, SmallHeaderSize)
+		binary.BigEndian.PutUint32(data, uint32(bi.Size))
+	} else {
+		data = make([]byte, LargeHeaderSize)
+		binary.BigEndian.PutUint32(data, 1)
+		binary.BigEndian.PutUint64(data[SmallHeaderSize:], bi.Size)
+	}
+	data[4] = bi.Type[0]
+	data[5] = bi.Type[1]
+	data[6] = bi.Type[2]
+	data[7] = bi.Type[3]
+
+	if _, err := w.Write(data); err != nil {
+		return nil, err
+	}
+
+	return &BoxInfo{
+		Offset:      uint64(offset),
+		Size:        bi.Size - bi.HeaderSize + uint64(len(data)),
+		HeaderSize:  uint64(len(data)),
+		Type:        bi.Type,
+		ExtendToEOF: bi.ExtendToEOF,
+	}, nil
+}
+
+// ReadBoxInfo reads common fields which are defined as "Box" class member at ISO/IEC 14496-12.
+func ReadBoxInfo(r io.ReadSeeker) (*BoxInfo, error) {
+	offset, err := r.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return nil, err
+	}
+
+	bi := &BoxInfo{
+		Offset: uint64(offset),
+	}
+
+	// read 8 bytes
+	buf := bytes.NewBuffer(make([]byte, 0, SmallHeaderSize))
+	if _, err := io.CopyN(buf, r, SmallHeaderSize); err != nil {
+		return nil, err
+	}
+	bi.HeaderSize += SmallHeaderSize
+
+	// pick size and type
+	data := buf.Bytes()
+	bi.Size = uint64(binary.BigEndian.Uint32(data))
+	bi.Type = BoxType{data[4], data[5], data[6], data[7]}
+
+	if bi.Size == 0 {
+		// box extends to end of file
+		offsetEOF, err := r.Seek(0, io.SeekEnd)
+		if err != nil {
+			return nil, err
+		}
+		bi.Size = uint64(offsetEOF) - bi.Offset
+		bi.ExtendToEOF = true
+		if _, err := bi.SeekToPayload(r); err != nil {
+			return nil, err
+		}
+
+	} else if bi.Size == 1 {
+		// read more 8 bytes
+		buf.Reset()
+		if _, err := io.CopyN(buf, r, LargeHeaderSize-SmallHeaderSize); err != nil {
+			return nil, err
+		}
+		bi.HeaderSize += LargeHeaderSize - SmallHeaderSize
+		bi.Size = binary.BigEndian.Uint64(buf.Bytes())
+	}
+
+	return bi, nil
+}
+
+func (bi *BoxInfo) SeekToStart(s io.Seeker) (int64, error) {
+	return s.Seek(int64(bi.Offset), io.SeekStart)
+}
+
+func (bi *BoxInfo) SeekToPayload(s io.Seeker) (int64, error) {
+	return s.Seek(int64(bi.Offset+bi.HeaderSize), io.SeekStart)
+}
+
+func (bi *BoxInfo) SeekToEnd(s io.Seeker) (int64, error) {
+	return s.Seek(int64(bi.Offset+bi.Size), io.SeekStart)
+}