public ByteVector Render()
{
ByteVector vector = new ByteVector();
// add the file identifier -- "3DI"
vector.Add(FileIdentifier);
// add the version number -- we always render a 2.4.0 tag regardless of what
// the tag originally was.
vector.Add((byte)4);
vector.Add((byte)0);
// render and add the flags
byte flags = 0;
if (Desynchronization)
{
flags |= 128;
}
if (ExtendedHeader)
{
flags |= 64;
}
if (ExperimentalIndicator)
{
flags |= 32;
}
flags |= 16;
vector.Add(flags);
// add the size
vector.Add(Id3v2SynchData.FromUInt(TagSize));
return(vector);
}
protected void Parse(ByteVector data)
{
if (data != null)
{
size = Id3v2SynchData.ToUInt(data.Mid(0, 4));
}
else
{
throw new ArgumentNullException("data");
}
}
protected void Parse(ByteVector data)
{
if (data.Count < Size)
{
return;
}
// do some sanity checking -- even in ID3v2.3.0 and less the tag size is a
// synch-safe integer, so all buffer must be less than 128. If this is not
// true then this is an invalid tag.
// note that we're doing things a little out of order here -- the size is
// later in the bytestream than the version
ByteVector sizeData = data.Mid(6, 4);
if (sizeData.Count != 4)
{
tagSize = 0;
TagLibDebugger.Debug("ID3v2.Header.Parse () - The tag size as read was 0 bytes!");
return;
}
foreach (byte b in sizeData)
{
if (b >= 128)
{
tagSize = 0;
TagLibDebugger.Debug("ID3v2.Header.Parse () - One of the size bytes in the id3v2 header was greater than the allowed 128.");
return;
}
}
// The first three buffer, data[0..2], are the File Identifier, "ID3". (structure 3.1 "file identifier")
// Read the version number from the fourth and fifth buffer.
majorVersion = data[3]; // (structure 3.1 "major version")
revisionNumber = data[4]; // (structure 3.1 "revision number")
// Read the flags, the first four bits of the sixth byte.
byte flags = data[5];
desynchronization = ((flags >> 7) & 1) == 1; // (structure 3.1.a)
extendedHeader = ((flags >> 6) & 1) == 1; // (structure 3.1.b)
experimentalIndicator = ((flags >> 5) & 1) == 1; // (structure 3.1.channelMode)
footerPresent = ((flags >> 4) & 1) == 1; // (structure 3.1.d)
// Get the size from the remaining four buffer (read above)
tagSize = Id3v2SynchData.ToUInt(sizeData); // (structure 3.1 "size")
}
public ByteVector Render()
{
ByteVector flags = new ByteVector(2, (byte)0); // just blank for the moment
return(frameId + Id3v2SynchData.FromUInt(frameSize) + flags);
}
public void SetData(ByteVector data, uint version)
{
if (data != null)
{
this.version = version;
if (version < 3)
{
// ID3v2.2
if (data.Count < 3)
{
TagLibDebugger.Debug("You must at least specify a frame ID.");
return;
}
// Set the frame ID -- the first three buffer
frameId = data.Mid(0, 3);
// If the full header information was not passed in, do not continue to the
// steps to parse the frame size and flags.
if (data.Count < 6)
{
frameSize = 0;
return;
}
frameSize = data.Mid(3, 3).ToUInt();
}
else if (version == 3)
{
// ID3v2.3
if (data.Count < 4)
{
TagLibDebugger.Debug("You must at least specify a frame ID.");
return;
}
// Set the frame ID -- the first four buffer
frameId = data.Mid(0, 4);
// If the full header information was not passed in, do not continue to the
// steps to parse the frame size and flags.
if (data.Count < 10)
{
frameSize = 0;
return;
}
// Set the size -- the frame size is the four buffer starting at byte four in
// the frame header (structure 4)
frameSize = data.Mid(4, 4).ToUInt();
// read the first byte of flags
tagAlterPreservation = ((data[8] >> 7) & 1) == 1; // (structure 3.3.1.a)
fileAlterPreservation = ((data[8] >> 6) & 1) == 1; // (structure 3.3.1.b)
readOnly = ((data[8] >> 5) & 1) == 1; // (structure 3.3.1.channelMode)
// read the second byte of flags
compression = ((data[9] >> 7) & 1) == 1; // (structure 3.3.1.index)
encryption = ((data[9] >> 6) & 1) == 1; // (structure 3.3.1.j)
groupingIdentity = ((data[9] >> 5) & 1) == 1; // (structure 3.3.1.k)
}
else
{
// ID3v2.4
if (data.Count < 4)
{
TagLibDebugger.Debug("You must at least specify a frame ID.");
return;
}
// Set the frame ID -- the first four buffer
frameId = data.Mid(0, 4);
// If the full header information was not passed in, do not continue to the
// steps to parse the frame size and flags.
if (data.Count < 10)
{
frameSize = 0;
return;
}
// Set the size -- the frame size is the four buffer starting at byte four in
// the frame header (structure 4)
frameSize = Id3v2SynchData.ToUInt(data.Mid(4, 4));
// read the first byte of flags
tagAlterPreservation = ((data[8] >> 6) & 1) == 1; // (structure 4.1.1.a)
fileAlterPreservation = ((data[8] >> 5) & 1) == 1; // (structure 4.1.1.b)
readOnly = ((data[8] >> 4) & 1) == 1; // (structure 4.1.1.channelMode)
// read the second byte of flags
groupingIdentity = ((data[9] >> 6) & 1) == 1; // (structure 4.1.2.header)
compression = ((data[9] >> 3) & 1) == 1; // (structure 4.1.2.k)
encryption = ((data[9] >> 2) & 1) == 1; // (structure 4.1.2.m)
desynchronization = ((data[9] >> 1) & 1) == 1; // (structure 4.1.2.n)
dataLengthIndicator = (data[9] & 1) == 1; // (structure 4.1.2.position)
}
}
else
{
throw new ArgumentNullException("data");
}
}
