/// <exception cref="Mp3net.InvalidDataException"></exception>
private int ScanBlock(byte[] bytes, int bytesRead, int absoluteOffset, int offset
)
{
while (offset < bytesRead - MINIMUM_BUFFER_LENGTH)
{
MpegFrame frame = new MpegFrame(bytes[offset], bytes[offset + 1], bytes[offset +
2], bytes[offset + 3]);
SanityCheckFrame(frame, absoluteOffset + offset);
int newEndOffset = absoluteOffset + offset + frame.GetLengthInBytes() - 1;
if (newEndOffset < GetMaxEndOffset())
{
endOffset = absoluteOffset + offset + frame.GetLengthInBytes() - 1;
frameCount++;
AddBitrate(frame.GetBitrate());
offset += frame.GetLengthInBytes();
}
else
{
break;
}
}
return offset;
}
private int ScanBlockForStart(byte[] bytes, int bytesRead, int absoluteOffset, int
offset)
{
while (offset < bytesRead - MINIMUM_BUFFER_LENGTH)
{
if (bytes[offset] == unchecked((byte)unchecked((int)(0xFF))) && (bytes[offset + 1
] & unchecked((byte)unchecked((int)(0xE0)))) == unchecked((byte)unchecked((int)(
0xE0))))
{
try
{
MpegFrame frame = new MpegFrame(bytes[offset], bytes[offset + 1], bytes[offset +
2], bytes[offset + 3]);
if (xingOffset < 0 && IsXingFrame(bytes, offset))
{
xingOffset = absoluteOffset + offset;
xingBitrate = frame.GetBitrate();
offset += frame.GetLengthInBytes();
}
else
{
startOffset = absoluteOffset + offset;
channelMode = frame.GetChannelMode();
emphasis = frame.GetEmphasis();
layer = frame.GetLayer();
modeExtension = frame.GetModeExtension();
sampleRate = frame.GetSampleRate();
version = frame.GetVersion();
copyright = frame.IsCopyright();
original = frame.IsOriginal();
frameCount++;
AddBitrate(frame.GetBitrate());
offset += frame.GetLengthInBytes();
return offset;
}
}
catch (InvalidDataException)
{
offset++;
}
}
else
{
offset++;
}
}
return offset;
}
/// <exception cref="Mp3net.InvalidDataException"></exception>
private void SanityCheckFrame(MpegFrame frame, int offset)
{
if (sampleRate != frame.GetSampleRate())
{
throw new InvalidDataException("Inconsistent frame header");
}
if (!layer.Equals(frame.GetLayer()))
{
throw new InvalidDataException("Inconsistent frame header");
}
if (!version.Equals(frame.GetVersion()))
{
throw new InvalidDataException("Inconsistent frame header");
}
if (offset + frame.GetLengthInBytes() > GetLength())
{
throw new InvalidDataException("Frame would extend beyond end of file");
}
}
