public id3v2Frame ReadFrame(BinaryReader br, int version)
{
char[] tagSize; // I use this to read the bytes in from the file
int[] bytes; // for bit shifting
ulong newSize = 0; // for the final number
int nameSize = 4;
if (version == 2)
{
nameSize = 3;
}
else if ((version == 3) || (version == 4))
{
nameSize = 4;
}
id3v2Frame f1 = new id3v2Frame();
f1.frameName = new string (br.ReadChars(nameSize));
f1.MajorVersion = version;
// in order to check for padding I have to build a string of 4 (or 3 if v2.2) null bytes
// there must be a better way to do this
char nullChar = System.Convert.ToChar(0);
StringBuilder sb = new StringBuilder(0,nameSize);
sb.Append(nullChar);
sb.Append(nullChar);
sb.Append(nullChar);
if (nameSize == 4)
{
sb.Append(nullChar);
}
if (f1.frameName == sb.ToString())
{
f1.padding = true;
return f1;
}
if (version == 2)
{
// only have 3 bytes for size ;
tagSize = br.ReadChars(3); // I use this to read the bytes in from the file
bytes = new int[3]; // for bit shifting
newSize = 0; // for the final number
// The ID3v2 tag size is encoded with four bytes
// where the most significant bit (bit 7)
// is set to zero in every byte,
// making a total of 28 bits.
// The zeroed bits are ignored
//
// Some bit grinding is necessary. Hang on.
bytes[3] = tagSize[2] | ((tagSize[1] & 1) << 7) ;
bytes[2] = ((tagSize[1] >> 1) & 63) | ((tagSize[0] & 3) << 6) ;
bytes[1] = ((tagSize[0] >> 2) & 31) ;
newSize = ((UInt64)bytes[3] |
((UInt64)bytes[2] << 8) |
((UInt64)bytes[1] << 16));
//End Dan Code
}
else if (version == 3 || version == 4)
{
// version 2.4
tagSize = br.ReadChars(4); // I use this to read the bytes in from the file
bytes = new int[4]; // for bit shifting
newSize = 0; // for the final number
// The ID3v2 tag size is encoded with four bytes
// where the most significant bit (bit 7)
// is set to zero in every byte,
// making a total of 28 bits.
// The zeroed bits are ignored
//
// Some bit grinding is necessary. Hang on.
bytes[3] = tagSize[3] | ((tagSize[2] & 1) << 7) ;
bytes[2] = ((tagSize[2] >> 1) & 63) | ((tagSize[1] & 3) << 6) ;
bytes[1] = ((tagSize[1] >> 2) & 31) | ((tagSize[0] & 7) << 5) ;
bytes[0] = ((tagSize[0] >> 3) & 15) ;
newSize = ((UInt64)bytes[3] |
((UInt64)bytes[2] << 8) |
((UInt64)bytes[1] << 16) |
((UInt64)bytes[0] << 24)) ;
//End Dan Code
}
f1.frameSize = newSize;
if (version > 2)
{
// versions 3+ have frame tags.
if (version == 3)
{
bool [] c;
// read teh tags
c = BitReader.ToBitBool(br.ReadByte());
f1.F_TagAlterPreservation = c[0];
f1.F_FileAlterPreservation= c[1];
f1.F_ReadOnly= c[2];
c = BitReader.ToBitBool(br.ReadByte());
f1.F_Compression= c[0];
f1.F_Encryption= c[1];
f1.F_GroupingIdentity= c[2];
}
else if (version == 4)
{
//%0abc0000 %0h00kmnp
//a - Tag alter preservation
// 0 Frame should be preserved.
// 1 Frame should be discarded.
// b - File alter preservation
// 0 Frame should be preserved.
//1 Frame should be discarded.
// c - Read only
// h - Grouping identity
// 0 Frame does not contain group information
// 1 Frame contains group information
// k - Compression
// 0 Frame is not compressed.
// 1 Frame is compressed using zlib [zlib] deflate method.
// If set, this requires the 'Data Length Indicator' bit
// to be set as well.
// m - Encryption
// 0 Frame is not encrypted.
// 1 Frame is encrypted.
// n - Unsynchronisation
// 0 Frame has not been unsynchronised.
// 1 Frame has been unsyrchronised.
// p - Data length indicator
// 0 There is no Data Length Indicator.
// 1 A data length Indicator has been added to the frame.
bool [] c;
// read teh tags
c = BitReader.ToBitBool(br.ReadByte());
f1.F_TagAlterPreservation = c[1];
f1.F_FileAlterPreservation= c[2];
f1.F_ReadOnly= c[3];
c = BitReader.ToBitBool(br.ReadByte());
f1.F_GroupingIdentity= c[1];
f1.F_Compression= c[4];
f1.F_Encryption= c[5];
f1.F_Unsynchronisation = c[6];
f1.F_DataLengthIndicator = c[7];
}
if (f1.frameSize > 0)
{
f1.frameContents = br.ReadBytes((int)f1.frameSize);
}
}
return f1;
}
private void ReadFrames()
{
id3v2Frame f = new id3v2Frame();
do
{
f = f.ReadFrame(br, this.MajorVersion);
// check if we have hit the padding.
if (f.padding == true)
{
//we hit padding. lets advance to end and stop reading.
br.BaseStream.Position = System.Convert.ToInt64(headerSize);
break;
}
this.frames.Add(f);
this.framesHash.Add(f.frameName, f);
#region frameprocessing
/*
else
{
// figure out which type it is
if (f.frameName.StartsWith("T"))
{
if (f.frameName.Equals("TXXX"))
{
ProcessTXXX(f);
}
else
{
ProcessTTYPE(f);
}
}
else
{
if (f.frameName.StartsWith("W"))
{
if (f.frameName.Equals("WXXX"))
{
ProcessWXXX(f);
}
else
{
ProcessWTYPE(f);
}
}
else
{
// if it isn't a muliple reader case (above) then throw it into the switch to process
switch (f.frameName)
{
case "IPLS":
ProcessIPLS(f);
break;
case "MCDI":
ProcessMCDI(f);
break;
case "UFID":
ProcessUFID(f);
break;
case "COMM":
ProcessCOMM(f);
break;
default:
frames.Add(f.frameName, f.frameContents);
AddItemToList(f.frameName, "non text");
break;
}
}
}
}*/
#endregion
} while (br.BaseStream.Position <= System.Convert.ToInt64(this.headerSize));
}
