public static byte[] Reader(DataFrameReader reader, int start, int unsyncedLength)
{
var result = new byte[unsyncedLength];
var n = start;
for (var i = 0; i < result.Length; i++)
{
var b = reader.ReadByte(n++);
if (b != 0xFF)
{
result[i] = b;
}
else
{
result[i] = reader.ReadByte(n++);
}
}
return(result);
}
/// <summary>
/// Reads a frame (check <see cref="State"/> before usage).
/// </summary>
/// <returns>Returns a frame if one left or null otherwise.</returns>
public bool ReadFrame(out ID3v2Frame frame)
{
if (State != ID3v2ReaderState.ReadFrames)
{
throw new InvalidOperationException(string.Format("Cannot read frame at state {0}", State));
}
frame = null;
if (m_Reader.BufferStartPosition >= m_BodyBytes)
{
if ((m_Header.Flags & ID3v2HeaderFlags.Footer) == 0)
{
// no footer, end of tag
State = ID3v2ReaderState.ReadEnd;
return(true);
}
State = ID3v2ReaderState.ReadFooter;
return(true);
}
if (m_Reader.ReadByte(0) == 0)
{
// check padding with zero bytes
byte[] data;
switch (m_Header.Version)
{
case 2:
{
var read = m_BodyBytes - m_Reader.BufferStartPosition;
data = m_Reader.GetBuffer((int)read);
State = ID3v2ReaderState.ReadEnd;
frame = null;
break;
}
case 3:
case 4:
{
// null frame, used by some encoders to implement padding, this is not allowed if footer present
if ((m_Header.Flags & ID3v2HeaderFlags.Footer) != 0)
{
throw new InvalidDataException(string.Format("Invalid padding frames inside of tag with footer!"));
}
// load padding bytes
var read = m_BodyBytes - m_Reader.BufferStartPosition;
data = m_Reader.GetBuffer((int)read);
State = ID3v2ReaderState.ReadEnd;
frame = null;
}
break;
default: return(false);
}
for (var i = 0; i < data.Length; i++)
{
if (data[i] != 0)
{
Trace.TraceError("Additional garbage in padding of ID3v2 tag!");
break;
}
}
return(false);
}
try
{
frame = new ID3v2Frame(m_Header, m_Reader);
}
catch (Exception ex)
{
Trace.TraceError("Error parsing id3 frame.");
Trace.TraceError(ex.ToString());
return(false);
}
return(true);
}
