| public SlurpBlock ( byte block, int offset, int count ) : void | ||
| block | byte | block of bytes to slurp |
| offset | int | starting point in the block |
| count | int | how many bytes within the block to slurp |
| return | void | |
public void SlurpBlock(byte[] block, int offset, int count)
{
if (block == null)
throw new Exception("The data buffer must not be null.");
// bzip algorithm
for (int i = 0; i < count; i++)
{
int x = offset + i;
byte b = block[x];
if (this.reverseBits)
{
UInt32 temp = (_register >> 24) ^ b;
_register = (_register << 8) ^ crc32Table[temp];
}
else
{
UInt32 temp = (_register & 0x000000FF) ^ b;
_register = (_register >> 8) ^ crc32Table[temp];
}
}
_TotalBytesRead += count;
}
/// <summary>
/// Read from the stream
/// </summary>
/// <param name="buffer">the buffer to read</param>
/// <param name="offset">the offset at which to start</param>
/// <param name="count">the number of bytes to read</param>
/// <returns>the number of bytes actually read</returns>
public override int Read(byte[] buffer, int offset, int count)
{
int bytesToRead = count;
// Need to limit the # of bytes returned, if the stream is intended to have
// a definite length. This is especially useful when returning a stream for
// the uncompressed data directly to the application. The app won't
// necessarily read only the UncompressedSize number of bytes. For example
// wrapping the stream returned from OpenReader() into a StreadReader() and
// calling ReadToEnd() on it, We can "over-read" the zip data and get a
// corrupt string. The length limits that, prevents that problem.
if (_lengthLimit != UnsetLengthLimit)
{
if (_Crc32.TotalBytesRead >= _lengthLimit)
{
return(0); // EOF
}
var bytesRemaining = _lengthLimit - _Crc32.TotalBytesRead;
if (bytesRemaining < count)
{
bytesToRead = (int)bytesRemaining;
}
}
int n = _innerStream.Read(buffer, offset, bytesToRead);
if (n > 0)
{
_Crc32.SlurpBlock(buffer, offset, n);
}
return(n);
}
