/// <summary>
/// Reads the raw data from a specified stream.
/// </summary>
/// <param name="stream">The stream to read from.</param>
public void Read(Stream stream)
{
// Check for 'ID3' marker
byte[] identifier = stream.Read(3);
if (!(identifier[0] == 0x49 && identifier[1] == 0x44 && identifier[2] == 0x33))
{
return;
}
// Read the header
_id3v2Header = new ID3v2Header(stream, false);
TagReadingInfo tagReadingInfo = new TagReadingInfo(_id3v2Header.TagVersion);
if (_id3v2Header.UsesUnsynchronization)
{
tagReadingInfo.TagVersionOptions = TagVersionOptions.Unsynchronized;
}
else
{
tagReadingInfo.TagVersionOptions = TagVersionOptions.None;
}
if (_id3v2Header.HasExtendedHeader)
{
_id3v2ExtendedHeader = new ID3v2ExtendedHeader(tagReadingInfo, stream);
}
int frameIDSize = (tagReadingInfo.TagVersion == ID3v2TagVersion.ID3v22 ? 3 : 4);
int bytesRead;
int readUntil;
#region <<< ID3v2.4 - Guess if syncsafe frame size was used or not >>>
if (_id3v2Header.TagVersion == ID3v2TagVersion.ID3v24)
{
bool isID3v24SyncSafe = true;
bytesRead = 0;
readUntil = _id3v2Header.TagSize - _id3v2ExtendedHeader.SizeIncludingSizeBytes - frameIDSize;
long initialPosition = stream.Position;
while (bytesRead < readUntil)
{
byte[] frameIDBytes = stream.Read(frameIDSize);
// TODO: Noticed some tags contain 0x00 'E' 'N' as a FrameID. Frame is well structured
// and other frames follow. I believe the below (keep reading+looking) will cover this issue.
// If character is not a letter or number, padding reached, audio began,
// or otherwise the frame is not readable
if (frameIDBytes[0] < 0x30 || frameIDBytes[0] > 0x5A ||
frameIDBytes[1] < 0x30 || frameIDBytes[1] > 0x5A ||
frameIDBytes[2] < 0x30 || frameIDBytes[2] > 0x5A ||
frameIDBytes[3] < 0x30 || frameIDBytes[3] > 0x5A)
{
// TODO: Try to keep reading and look for a valid frame
if (frameIDBytes[0] != 0 && frameIDBytes[0] != 0xFF)
{
/*String msg = String.Format("Out of range FrameID - 0x{0:X}|0x{1:X}|0x{2:X}|0x{3:X}",
* tmpFrameIDBytes[0], tmpFrameIDBytes[1], tmpFrameIDBytes[2],
* tmpFrameIDBytes[3]);
* Trace.WriteLine(msg);*/
}
break;
}
int frameSize = stream.ReadInt32();
if (frameSize > 0xFF)
{
if ((frameSize & 0x80) == 0x80)
{
isID3v24SyncSafe = false; break;
}
if ((frameSize & 0x8000) == 0x8000)
{
isID3v24SyncSafe = false; break;
}
if ((frameSize & 0x800000) == 0x800000)
{
isID3v24SyncSafe = false; break;
}
if (bytesRead + frameSize + 10 == _id3v2Header.TagSize)
{
// Could give a false positive, but relatively unlikely (famous last words, huh?)
isID3v24SyncSafe = false;
break;
}
else
{
stream.Seek(-4, SeekOrigin.Current); // go back to read sync-safe version
int syncSafeFrameSize = ID3v2Utils.ReadInt32SyncSafe(stream);
long currentPosition = stream.Position;
bool isValidAtSyncSafe = true;
bool isValidAtNonSyncSafe = true;
// TODO - if it's the last frame and there is padding, both would indicate false
// Use the one that returns some padding bytes opposed to bytes with non-zero values (could be frame data)
// If non sync-safe reads past the end of the tag, then it's sync safe
// Testing non-sync safe since it will always be bigger than the sync safe integer
if (currentPosition + frameSize + 2 >= readUntil)
{
isID3v24SyncSafe = true; break;
}
// Test non-sync safe
stream.Seek(currentPosition + frameSize + 2, SeekOrigin.Begin);
frameIDBytes = stream.Read(frameIDSize);
if (frameIDBytes[0] < 0x30 || frameIDBytes[0] > 0x5A ||
frameIDBytes[1] < 0x30 || frameIDBytes[1] > 0x5A ||
frameIDBytes[2] < 0x30 || frameIDBytes[2] > 0x5A ||
frameIDBytes[3] < 0x30 || frameIDBytes[3] > 0x5A)
{
isValidAtNonSyncSafe = false;
}
// Test sync-safe
stream.Seek(currentPosition + syncSafeFrameSize + 2, SeekOrigin.Begin);
frameIDBytes = stream.Read(frameIDSize);
if (frameIDBytes[0] < 0x30 || frameIDBytes[0] > 0x5A ||
frameIDBytes[1] < 0x30 || frameIDBytes[1] > 0x5A ||
frameIDBytes[2] < 0x30 || frameIDBytes[2] > 0x5A ||
frameIDBytes[3] < 0x30 || frameIDBytes[3] > 0x5A)
{
isValidAtSyncSafe = false;
}
// if they're equal, we'll just have to go with syncsafe, since that's the spec
if (isValidAtNonSyncSafe != isValidAtSyncSafe)
{
isID3v24SyncSafe = isValidAtSyncSafe;
}
break;
}
}
stream.Seek(frameSize + 2, SeekOrigin.Current);
bytesRead += frameSize + 10;
}
stream.Position = initialPosition;
if (isID3v24SyncSafe == false)
{
tagReadingInfo.TagVersionOptions |= TagVersionOptions.UseNonSyncSafeFrameSizeID3v24;
}
}
else if (_id3v2Header.TagVersion == ID3v2TagVersion.ID3v22)
{
bool isID3v22CorrectSize = true;
bytesRead = 0;
readUntil = _id3v2Header.TagSize - _id3v2ExtendedHeader.SizeIncludingSizeBytes - frameIDSize;
long initialPosition = stream.Position;
stream.Read(frameIDSize);
UnknownFrame unknownFrame = new UnknownFrame(null, tagReadingInfo, stream);
bytesRead += unknownFrame.FrameHeader.FrameSizeTotal;
if (bytesRead < readUntil)
{
byte[] frameIDBytes = stream.Read(frameIDSize);
// TODO: Noticed some tags contain 0x00 'E' 'N' as a FrameID. Frame is well structured
// and other frames follow. I believe the below (keep reading+looking) will cover this issue.
// If character is not a letter or number, padding reached, audio began,
// or otherwise the frame is not readable
if (frameIDBytes[0] < 0x30 || frameIDBytes[0] > 0x5A)
{
if (frameIDBytes[1] >= 0x30 && frameIDBytes[1] <= 0x5A &&
frameIDBytes[2] >= 0x30 && frameIDBytes[2] <= 0x5A)
{
Trace.WriteLine("ID3v2.2 frame size off by 1 byte");
isID3v22CorrectSize = false;
}
}
}
stream.Position = initialPosition;
if (isID3v22CorrectSize == false)
{
tagReadingInfo.TagVersionOptions |= TagVersionOptions.AddOneByteToSize;
}
}
#endregion <<< ID3v2.4 - Guess if syncsafe frame size was used or not >>>
readUntil = _id3v2Header.TagSize - _id3v2ExtendedHeader.SizeIncludingSizeBytes - frameIDSize;
Read(stream, _id3v2Header.TagVersion, tagReadingInfo, readUntil, frameIDSize);
}
/// <summary>
/// Initializes a new instance of the <see cref="ID3v2Tag"/> class.
/// </summary>
public ID3v2Tag()
{
_id3v2Header = new ID3v2Header();
_id3v2ExtendedHeader = new ID3v2ExtendedHeader();
}