diff --git a/id3v2.go b/id3v2.go index 47ae02c..fe19570 100644 --- a/id3v2.go +++ b/id3v2.go @@ -57,20 +57,40 @@ func readID3v2Header(r io.Reader) (*ID3v2Header, error) { // ID3v2FrameFlags is a type which represents the flags which can be set on an ID3v2 frame. type ID3v2FrameFlags struct { - // Message + // Message (ID3 2.3.0 and 2.4.0) TagAlterPreservation bool FileAlterPreservation bool ReadOnly bool - // Format - GroupIdentity bool - Compression bool - Encryption bool + // Format (ID3 2.3.0 and 2.4.0) + Compression bool + Encryption bool + GroupIdentity bool + // ID3 2.4.0 only (see http://id3.org/id3v2.4.0-structure sec 4.1) Unsynchronisation bool DataLengthIndicator bool } -func readID3v2FrameFlags(r io.Reader) (*ID3v2FrameFlags, error) { +func readID3v23FrameFlags(r io.Reader) (*ID3v2FrameFlags, error) { + b, err := readBytes(r, 2) + if err != nil { + return nil, err + } + + msg := b[0] + fmt := b[1] + + return &ID3v2FrameFlags{ + TagAlterPreservation: getBit(msg, 7), + FileAlterPreservation: getBit(msg, 6), + ReadOnly: getBit(msg, 5), + Compression: getBit(fmt, 7), + Encryption: getBit(fmt, 6), + GroupIdentity: getBit(fmt, 5), + }, nil +} + +func readID3v24FrameFlags(r io.Reader) (*ID3v2FrameFlags, error) { b, err := readBytes(r, 2) if err != nil { return nil, err @@ -83,12 +103,13 @@ func readID3v2FrameFlags(r io.Reader) (*ID3v2FrameFlags, error) { TagAlterPreservation: getBit(msg, 6), FileAlterPreservation: getBit(msg, 5), ReadOnly: getBit(msg, 4), - GroupIdentity: getBit(fmt, 7), + GroupIdentity: getBit(fmt, 6), Compression: getBit(fmt, 3), Encryption: getBit(fmt, 2), Unsynchronisation: getBit(fmt, 1), DataLengthIndicator: getBit(fmt, 0), }, nil + } func readID3v2_2FrameHeader(r io.Reader) (name string, size int, headerSize int, err error) { @@ -150,7 +171,7 @@ func readID3v2Frames(r io.Reader, h *ID3v2Header) (map[string]interface{}, error if err != nil { return nil, err } - flags, err = readID3v2FrameFlags(r) + flags, err = readID3v23FrameFlags(r) headerSize += 2 case ID3v2_4: @@ -158,7 +179,7 @@ func readID3v2Frames(r io.Reader, h *ID3v2Header) (map[string]interface{}, error if err != nil { return nil, err } - flags, err = readID3v2FrameFlags(r) + flags, err = readID3v24FrameFlags(r) headerSize += 2 } @@ -180,18 +201,22 @@ func readID3v2Frames(r io.Reader, h *ID3v2Header) (map[string]interface{}, error offset += headerSize + size - // Check this stuff out... - if flags != nil && flags.DataLengthIndicator { - _, err = read7BitChunkedInt(r, 4) // read 4 - if err != nil { - return nil, err + if flags != nil { + if flags.Compression { + _, err = read7BitChunkedInt(r, 4) // read 4 + if err != nil { + return nil, err + } + size -= 4 } - size -= 4 - } - if flags != nil && flags.Unsynchronisation { - // FIXME: Implement this. - continue + if flags.Encryption { + _, err = readBytes(r, 1) // read 1 byte of encryption method + if err != nil { + return nil, err + } + size -= 1 + } } b, err := readBytes(r, size)