private byte[] GetTagBytes(Id3Tag tag)
{
var bytes = new List <byte>();
bytes.AddRange(AsciiEncoding.GetBytes("ID3"));
bytes.AddRange(new byte[] { 3, 0, 0 });
foreach (Id3Frame frame in tag.Frames)
{
if (frame.IsAssigned)
{
FrameHandler mapping = FrameHandlers[frame.GetType()];
if (mapping != null)
{
byte[] frameBytes = mapping.Encoder(frame);
bytes.AddRange(AsciiEncoding.GetBytes(GetFrameIdFromFrame(frame)));
bytes.AddRange(SyncSafeNumber.EncodeNormal(frameBytes.Length));
bytes.AddRange(new byte[] { 0, 0 });
bytes.AddRange(frameBytes);
}
}
}
int framesSize = bytes.Count - 6;
bytes.InsertRange(6, SyncSafeNumber.EncodeSafe(framesSize));
return(bytes.ToArray());
}
private static int GetTagSize(Stream stream)
{
stream.Seek(6, SeekOrigin.Begin);
var sizeBytes = new byte[4];
stream.Read(sizeBytes, 0, 4);
int tagSize = SyncSafeNumber.DecodeSafe(sizeBytes, 0, 4) + 10;
return(tagSize);
}
internal override byte[] GetTagBytes(Stream stream)
{
if (!HasTag(stream))
{
return(null);
}
var sizeBytes = new byte[4];
stream.Seek(6, SeekOrigin.Begin);
stream.Read(sizeBytes, 0, 4);
int tagSize = SyncSafeNumber.DecodeSafe(sizeBytes, 0, 4);
var tagBytes = new byte[tagSize + 10];
stream.Seek(0, SeekOrigin.Begin);
stream.Read(tagBytes, 0, tagBytes.Length);
return(tagBytes);
}
internal override Id3Tag ReadTag(Stream stream)
{
if (!HasTag(stream))
{
return(null);
}
var tag = new Id3Tag {
MajorVersion = 2,
MinorVersion = 3,
Family = Id3TagFamily.Version2x,
IsSupported = true,
};
stream.Seek(4, SeekOrigin.Begin);
var headerBytes = new byte[6];
stream.Read(headerBytes, 0, 6);
var headerContainer = new Id3v2Header();
tag.AdditionalData = headerContainer;
byte flags = headerBytes[1];
var header = new Id3v2StandardHeader {
Revision = headerBytes[0],
Unsyncronization = (flags & 0x80) > 0,
ExtendedHeader = (flags & 0x40) > 0,
Experimental = (flags & 0x20) > 0
};
headerContainer.Header = header;
int tagSize = SyncSafeNumber.DecodeSafe(headerBytes, 2, 4);
var tagData = new byte[tagSize];
stream.Read(tagData, 0, tagSize);
int currentPos = 0;
if (header.ExtendedHeader)
{
SyncSafeNumber.DecodeSafe(tagData, currentPos, 4);
currentPos += 4;
var extendedHeader = new Id3v2ExtendedHeader {
PaddingSize = SyncSafeNumber.DecodeNormal(tagData, currentPos + 2, 4)
};
if ((tagData[currentPos] & 0x80) > 0)
{
extendedHeader.Crc32 = SyncSafeNumber.DecodeNormal(tagData, currentPos + 6, 4);
currentPos += 10;
}
else
{
currentPos += 6;
}
headerContainer.ExtendedHeader = extendedHeader;
}
while (currentPos < tagSize && tagData[currentPos] != 0x00)
{
string frameId = AsciiEncoding.GetString(tagData, currentPos, 4);
currentPos += 4;
int frameSize = SyncSafeNumber.DecodeNormal(tagData, currentPos, 4);
currentPos += 4;
var frameFlags = (ushort)((tagData[currentPos] << 0x08) + tagData[currentPos + 1]);
currentPos += 2;
var frameData = new byte[frameSize];
Array.Copy(tagData, currentPos, frameData, 0, frameSize);
FrameHandler mapping = FrameHandlers[frameId];
if (mapping != null && mapping.Decoder != null)
{
Id3Frame frame = mapping.Decoder(frameData);
tag.Frames.Add(frame);
}
currentPos += frameSize;
}
return(tag);
}
internal override Id3Tag ReadTag(Stream stream, out object additionalData)
{
if (!HasTag(stream))
{
additionalData = null;
return(null);
}
Id3Tag tag = CreateTag();
stream.Seek(4, SeekOrigin.Begin);
var headerBytes = new byte[6];
stream.Read(headerBytes, 0, 6);
var headerContainer = new Id3V2Header();
additionalData = headerContainer;
byte flags = headerBytes[1];
var header = new Id3V2StandardHeader {
Revision = headerBytes[0],
Unsyncronization = (flags & 0x80) > 0,
ExtendedHeader = (flags & 0x40) > 0,
Experimental = (flags & 0x20) > 0
};
headerContainer.Header = header;
int tagSize = SyncSafeNumber.DecodeSafe(headerBytes, 2, 4);
var tagData = new byte[tagSize];
stream.Read(tagData, 0, tagSize);
var currentPos = 0;
if (header.ExtendedHeader)
{
SyncSafeNumber.DecodeSafe(tagData, currentPos, 4);
currentPos += 4;
var extendedHeader = new Id3V2ExtendedHeader {
PaddingSize = SyncSafeNumber.DecodeNormal(tagData, currentPos + 2, 4)
};
if ((tagData[currentPos] & 0x80) > 0)
{
extendedHeader.Crc32 = SyncSafeNumber.DecodeNormal(tagData, currentPos + 6, 4);
currentPos += 10;
}
else
{
currentPos += 6;
}
headerContainer.ExtendedHeader = extendedHeader;
}
while (currentPos < tagSize && tagData[currentPos] != 0x00)
{
string frameId = Encoding.ASCII.GetString(tagData, currentPos, 4);
currentPos += 4;
int frameSize = SyncSafeNumber.DecodeNormal(tagData, currentPos, 4);
currentPos += 4;
var frameFlags = (ushort)((tagData[currentPos] << 0x08) + tagData[currentPos + 1]);
currentPos += 2;
var frameData = new byte[frameSize];
Array.Copy(tagData, currentPos, frameData, 0, frameSize);
FrameHandler mapping = FrameHandlers[frameId];
if (mapping != null)
{
Id3Frame frame = mapping.Decoder(frameData);
tag.AddUntypedFrame(frame);
}
currentPos += frameSize;
}
return(tag);
}
