/// <summary>
/// Reads data from this stream
/// </summary>
/// <param name="buffer"></param>
/// <param name="offset"></param>
/// <param name="count"></param>
/// <returns></returns>
public override int Read(byte[] buffer, int offset, int count)
{
lock (this)
{
// 1. attempt to fill the circular buffer with enough data to meet our request
while (BufferEndPosition < position + count)
{
int sourceReadCount = count;
if (sourceReadCount % sourceStream.BlockAlign != 0)
{
sourceReadCount = (count + sourceStream.BlockAlign) - (count % sourceStream.BlockAlign);
}
int sourceRead = sourceStream.Read(GetSourceBuffer(sourceReadCount), 0, sourceReadCount);
circularBuffer.Write(GetSourceBuffer(sourceReadCount), 0, sourceRead);
if (sourceRead == 0)
{
// assume we have run out of data
break;
}
}
// 2. discard any unnecessary stuff from the start
if (bufferStartPosition < position)
{
circularBuffer.Advance((int)(position - bufferStartPosition));
bufferStartPosition = position;
}
// 3. now whatever is in the buffer we can return
int bytesRead = circularBuffer.Read(buffer, offset, count);
position += bytesRead;
// anything left in buffer is at start position
bufferStartPosition = position;
return(bytesRead);
}
}