public void processFlags()
{
switch (MajorVersion)
{
default:
case 2:
//ID3v2.2 = ExtendedHeader Not Supported
break;
case 3:
//ID3v2.3 = %x0000000 00000000 (x = CRCPresent)
CRCPresent = ((RawData[4] & 0x80) == 0x80);
PaddingSize = ID3Base.expand(RawData[6], RawData[7], RawData[8], RawData[9]);
if (CRCPresent)
{
CRCData = ID3Base.expand(RawData[10], RawData[11], RawData[12], RawData[13]);
}
break;
case 4:
//ID3v2.4 = %0bcd0000 (b = TagIsUpdate, c = CRCPresent, d = TagRestrictions)
int numOfFlags = (int)RawData[4];
for (int i = 0; i < numOfFlags; ++i)
{
TagIsUpdate = ((RawData[5 + i] & 0x40) == 0x40);
CRCPresent = ((RawData[5 + i] & 0x20) == 0x20);
TagRestrictions = ((RawData[5 + i] & 0x10) == 0x10);
}
int DataStartingPoint = 5 + numOfFlags;
if (TagIsUpdate)
{
//Flag Data Length is $00
DataStartingPoint++;
}
if (CRCPresent)
{
//Flag Data Length is $05
DataStartingPoint++;
CRCData = ID3Base.syncsafe(RawData[DataStartingPoint],
RawData[DataStartingPoint + 1],
RawData[DataStartingPoint + 2],
RawData[DataStartingPoint + 3],
RawData[DataStartingPoint + 4]);
DataStartingPoint += 5;
}
if (TagRestrictions)
{
//Flag data length is $01
DataStartingPoint++;
//Restrictions %ppqr rstt
//p - Tag Size Restrictions
byte p = (byte)(RawData[DataStartingPoint] & 0xC0);
switch (p)
{
case 0x00: //0000 0000 [00] - No more than 128 frames and 1 MB total tag size.
break;
case 0x40: //0100 0000 [01] - No more than 64 frames and 128 KB total tag size.
break;
case 0x80: //1000 0000 [10] - No more than 32 frames and 40 KB total tag size.
break;
case 0xC0: //1100 0000 [11] - No more than 32 frames and 4 KB total tag size.
break;
}
//q - Text encoding restrictions
byte q = (byte)(RawData[DataStartingPoint] & 0x20);
switch (q)
{
case 0x00: //0000 0000 [0] - No Restrictions
break;
case 0x20: //0010 0000 [1] - Strings are only encoded with ISO-8859-1 [ISO-8859-1] or UTF-8 [UTF-8].
break;
}
//r - Text fields size restrictions
byte r = (byte)(RawData[DataStartingPoint] & 0x18);
switch (r)
{
case 0x00: //0000 0000 [00] - No restrictions
break;
case 0x08: //0000 1000 [01] - No string is longer than 1024 characters.
break;
case 0x10: //0001 0000 [10] - No string is longer than 128 characters.
break;
case 0x18: //0001 1000 [11] - No string is longer than 30 characters.
break;
}
//s - Image encoding restrictions
byte s = (byte)(RawData[DataStartingPoint] & 0x04);
switch (s)
{
case 0x00: //0000 0000 [0] - No restrictions
break;
case 0x04: //0000 0100 [1] - Images are encoded only with PNG [PNG] or JPEG [JFIF].
break;
}
//t - Image size restrictions
byte t = (byte)(RawData[DataStartingPoint] & 0x03);
switch (t)
{
case 0x00: //0000 0000 [00] - No restrictions
break;
case 0x01: //0000 0001 [01] - All images are 256x256 pixels or smaller.
break;
case 0x02: //0000 0010 [10] - All images are 64x64 pixels or smaller.
break;
case 0x03: //0000 0011 [11] - All images are exactly 64x64 pixels, unless required otherwise.
break;
}
}
break;
}
}
public ID3v2Tag(FileStream fs, long lngStartOffset)
{
//Store FileStreams current position
long fsOriginalPosition = fs.Position;
setDefaultValues();
Regex ProperFrameNamePattern = new Regex("[A-Z0-9]");
byte[] bytHeaderID3 = new byte[10];
fs.Position = lngStartOffset;
fs.Read(bytHeaderID3, 0, 10);
//ID3v2.X should start with "ID3"
if ((char)bytHeaderID3[0] == 'I' && (char)bytHeaderID3[1] == 'D' && (char)bytHeaderID3[2] == '3')
{
Position = lngStartOffset;
//Major and Minor Versions should NOT be 0xFF
MajorVersion = (bytHeaderID3[3] != 0xFF) ? (int)bytHeaderID3[3] : 0;
MinorVersion = (bytHeaderID3[4] != 0xFF) ? (int)bytHeaderID3[4] : 0;
ProcessFlags(bytHeaderID3[5]);
/*
* ID3v2 Uses synchsafe integers, which skip the largest bit (farthest left) of each byte.
*
* See http://www.id3.org/id3v2.4.0-structure and http://id3lib.sourceforge.net/id3/id3v2.3.0.html#sec3.1
*/
//Console.WriteLine("ID3v2.{0:D}.{1:D} Exists", tag.MajorVersion, tag.MinorVersion);
//Max size for tag size = 2^28 = 268435456 bytes = 256MB; int.MaxValue = 2147483647 bytes = 2048MB
TagSize = (uint)ID3Base.syncsafe(bytHeaderID3[6], bytHeaderID3[7], bytHeaderID3[8], bytHeaderID3[9]); //(int)((bytHeaderID3[6] << 21) | (bytHeaderID3[7] << 14) | (bytHeaderID3[8] << 7) | bytHeaderID3[9]);
//Console.WriteLine("Len (Bytes): {0:D}", (ulong)( (bytHeaderID3[6] << 21) | (bytHeaderID3[7] << 14) | (bytHeaderID3[8] << 7) | bytHeaderID3[9] ));
//Console.WriteLine("NUMBER: {0:D}", (ulong)( (0x00<<21) | (0x00<<14) | (0x02<<7) | (0x01) ));
//Console.WriteLine("OUTPUT: {0:X}, {1:X}, {2:X}, {3:X}", bytHeaderID3[6], bytHeaderID3[7], bytHeaderID3[8], bytHeaderID3[9]);
Exists = true;
//Experimental - Extended Header Implementation
ExtendedHeader.setID3Version(MajorVersion);
if (ExtendedHeader.Exists && MajorVersion > 2)
{
byte[] EH_Size = new byte[4];
fs.Read(EH_Size, 0, 4);
if (MajorVersion == 3)
{
//Extended Header size, excluding itself; only 6 or 10 bytes (6 if no CRC Data, 10 if CRC Data [4 bytes for CRC])
ExtendedHeader.size = (int)ID3Base.expand(EH_Size[0], EH_Size[1], EH_Size[2], EH_Size[3]);
byte[] headerAndData = new byte[4 + ExtendedHeader.size];
fs.Position = lngStartOffset + 10;
fs.Read(headerAndData, 0, headerAndData.Length);
ExtendedHeader.setData(headerAndData);
}
else if (MajorVersion == 4)
{
//Whole Extended Header
ExtendedHeader.size = ID3Base.syncsafe(EH_Size[0], EH_Size[1], EH_Size[2], EH_Size[3]);
byte[] headerAndData = new byte[ExtendedHeader.size];
fs.Position = lngStartOffset + 10;
fs.Read(headerAndData, 0, headerAndData.Length);
ExtendedHeader.setData(headerAndData);
}
}
//ID3v2.2.X uses 3 letter identifiers versus the 4 letter identifiers in 2.3.X and 2.4.X
if (!Compression)
{
Console.WriteLine("ID3v2.{0:D} Detected...", MajorVersion);
int totalFrameSize = 0;
int AdditionalBytes = 10;
if (FooterExists)
{
AdditionalBytes = 20;
}
while (!PaddingExists && fs.Position < TagSize + AdditionalBytes) //(tag.TagSize + 10) == End Position (+10 for Original Header, +20 For Original Header and Footer [if present])
{
if (MajorVersion == 2)
{
byte[] TempHeader = new byte[6];
fs.Read(TempHeader, 0, 6);
if (TempHeader[0] == 0x00 && TempHeader[1] == 0x00 && TempHeader[2] == 0x00)
{
PaddingExists = true;
}
else
{
Console.WriteLine("HEADER[{0}{1}{2}]", (char)TempHeader[0], (char)TempHeader[1], (char)TempHeader[2]);
string FrameHeaderName = ((char)TempHeader[0]).ToString() +
((char)TempHeader[1]).ToString() +
((char)TempHeader[2]).ToString();
if (!ProperFrameNamePattern.IsMatch(FrameHeaderName))
{
Console.WriteLine("Invalid ID3v2 Header");
Valid = false;
break;
}
if (Frames.ContainsKey(FrameHeaderName))
{
Frames[FrameHeaderName].Add(new ID3v2Frame(FrameHeaderName, MajorVersion));
}
else
{
List <ID3v2Frame> FrameList = new List <ID3v2Frame>();
FrameList.Add(new ID3v2Frame(FrameHeaderName, MajorVersion));
Frames.Add(FrameHeaderName, FrameList);
}
int currentFrameIndex = Frames[FrameHeaderName].Count - 1;
ID3v2Frame currentFrame = Frames[FrameHeaderName][currentFrameIndex];
currentFrame.getFrameFlags((byte)0x00, (byte)0x00, AllFramesUnsynced);
//Frame Size
currentFrame.FrameSize = (int)ID3Base.expand(TempHeader[3], TempHeader[4], TempHeader[5]); //(int)((TempHeader[3] << 16) | (TempHeader[4] << 8) | (TempHeader[5]));
totalFrameSize += currentFrame.FrameSize + 6; //+6 for Frame Header
//Set FrameData
byte[] tempData = new byte[currentFrame.FrameSize];
fs.Read(tempData, 0, currentFrame.FrameSize);
currentFrame.getFrameData(tempData);
}
}
else
{
byte[] TempHeader = new byte[10];
fs.Read(TempHeader, 0, 10);
//All Tags must be 4 Characters (characters capital A-Z and 0-9; not null)
if (!FooterExists && (TempHeader[0] == 0x00 || TempHeader[1] == 0x00 || TempHeader[2] == 0x00 || TempHeader[3] == 0x00))
{
//Nothing Here but Padding; Skip to the end of the tag
//Footer and Padding are Mutually Exclusive
PaddingExists = true;
}
else
{
Console.WriteLine("HEADER[{0}{1}{2}{3}]", (char)TempHeader[0], (char)TempHeader[1], (char)TempHeader[2], (char)TempHeader[3]);
//Get the Frame Name
string FrameHeaderName = ((char)TempHeader[0]).ToString() +
((char)TempHeader[1]).ToString() +
((char)TempHeader[2]).ToString() +
((char)TempHeader[3]).ToString();
if (!ProperFrameNamePattern.IsMatch(FrameHeaderName))
{
Console.WriteLine("Invalid ID3v2 Header");
Valid = false;
break;
}
if (Frames.ContainsKey(FrameHeaderName))
{
Frames[FrameHeaderName].Add(new ID3v2Frame(FrameHeaderName, MajorVersion));
}
else
{
List <ID3v2Frame> FrameList = new List <ID3v2Frame>();
FrameList.Add(new ID3v2Frame(FrameHeaderName, MajorVersion));
Frames.Add(FrameHeaderName, FrameList);
}
//Keep Track of which count of the Frame we are working on (some frames may be in the tag more than once)
int currentFrameIndex = Frames[FrameHeaderName].Count - 1;
ID3v2Frame currentFrame = Frames[FrameHeaderName][currentFrameIndex];
currentFrame.getFrameFlags(TempHeader[8], TempHeader[9], AllFramesUnsynced);
//ID3v2.3 does not appear to use syncsafe numbers for frame sizes (2.4 does)
bool unsync = currentFrame.FF_Unsynchronisation;
if (MajorVersion > 3)
{
currentFrame.FrameSize = ID3Base.syncsafe(TempHeader[4], TempHeader[5], TempHeader[6], TempHeader[7]);
}
else
{
currentFrame.FrameSize = (int)ID3Base.expand(TempHeader[4], TempHeader[5], TempHeader[6], TempHeader[7]);//(int)((TempHeader[4] << 24) | (TempHeader[5] << 16) | (TempHeader[6] << 8) | (TempHeader[7]));
}
totalFrameSize += currentFrame.FrameSize + 10; //+10 for Frame Header
//Set FrameData
byte[] tempData = new byte[currentFrame.FrameSize];
fs.Read(tempData, 0, currentFrame.FrameSize);
currentFrame.getFrameData(tempData);
}
}
}
Console.WriteLine("Padding Exsists: {0}", PaddingExists.ToString());
Console.WriteLine("TagSize: {0:D}, TotalFrameSize: {1:D}", TagSize, totalFrameSize);
Console.WriteLine();
}
}
ProcessFrames();
fs.Position = fsOriginalPosition;
}