/// <summary>
/// learn from 02_decompress.c
/// </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)
{
if (buffer == null) throw new ArgumentNullException(nameof(buffer));
if (offset < 0) throw new ArgumentOutOfRangeException(nameof(offset));
if (count < 0) throw new ArgumentOutOfRangeException(nameof(count));
if (count + offset > buffer.Length) throw new ArgumentOutOfRangeException(nameof(count), "offset+count > buffer.length");
if (count == 0) return 0;
int cTotalRead = 0;
while (true)
{
// read from underlying stream
if (_lzma_stream.avail_in == UIntPtr.Zero && action == lzma_action.LZMA_RUN)
{
// read more data from underlying stream
var data = new byte[BUFSIZE];
var bytesRead = _stream.Read(data, 0, BUFSIZE);
if (bytesRead < BUFSIZE) action = lzma_action.LZMA_FINISH; // source stream has no more data
_lzma_stream.next_in = _inbuf;
_lzma_stream.avail_in = (UIntPtr)bytesRead;
Marshal.Copy(data, 0, _inbuf, bytesRead);
}
// try to read from existing outbuf
int cReadable = BUFSIZE - (int)(uint)_lzma_stream.avail_out - read_pos;
if (cReadable > 0)
{
var cCopy = Math.Min(cReadable, count - cTotalRead);
var p = Native.Is64Bit ? new IntPtr(_outbuf.ToInt64() + read_pos) : new IntPtr(_outbuf.ToInt32() + read_pos);
Marshal.Copy(p, buffer, offset + cTotalRead, cCopy);
cTotalRead += cCopy;
read_pos += cCopy;
Trace.Assert(cTotalRead <= count);
if (cTotalRead == count)
return cTotalRead;
}
// need to read more data from outbuf
// if previous decode returns LZMA_STREAM_END, there will be no more data
if (ret == lzma_ret.LZMA_STREAM_END)
return cTotalRead;
// otherwise, reset outbuf to recv more decompressed data from liblzma, or decompress is finished
Trace.Assert(read_pos + (uint)_lzma_stream.avail_out <= BUFSIZE);
if (_lzma_stream.avail_out == UIntPtr.Zero && read_pos + (uint)_lzma_stream.avail_out == BUFSIZE)
{
_lzma_stream.next_out = _outbuf;
_lzma_stream.avail_out = (UIntPtr)BUFSIZE;
read_pos = 0;
}
// do decompress
ret = Native.lzma_code(_lzma_stream, action);
if (ret != lzma_ret.LZMA_OK && ret != lzma_ret.LZMA_STREAM_END)
throw new Exception($"lzma_code returns {ret}");
}
}
/// <summary>
/// learn from 02_decompress.c
/// </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)
{
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException(nameof(offset));
}
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
if (count + offset > buffer.Length)
{
throw new ArgumentOutOfRangeException(nameof(count), "offset+count > buffer.length");
}
if (count == 0)
{
return(0);
}
int cTotalRead = 0;
while (true)
{
// read from underlying stream
if (_lzma_stream.avail_in == UIntPtr.Zero && action == lzma_action.LZMA_RUN)
{
// read more data from underlying stream
var data = new byte[BUFSIZE];
var bytesRead = _stream.Read(data, 0, BUFSIZE);
if (bytesRead == 0)
{
action = lzma_action.LZMA_FINISH; // source stream has no more data
}
_lzma_stream.next_in = _inbuf;
_lzma_stream.avail_in = (UIntPtr)bytesRead;
Marshal.Copy(data, 0, _inbuf, bytesRead);
}
// try to read from existing outbuf
int cReadable = BUFSIZE - (int)(uint)_lzma_stream.avail_out - read_pos;
if (cReadable > 0)
{
var cCopy = Math.Min(cReadable, count - cTotalRead);
var p = Native.Is64Bit ? new IntPtr(_outbuf.ToInt64() + read_pos) : new IntPtr(_outbuf.ToInt32() + read_pos);
Marshal.Copy(p, buffer, offset + cTotalRead, cCopy);
cTotalRead += cCopy;
read_pos += cCopy;
Trace.Assert(cTotalRead <= count);
if (cTotalRead == count)
{
return(cTotalRead);
}
}
// need to read more data from outbuf
// if previous decode returns LZMA_STREAM_END, there will be no more data
if (ret == lzma_ret.LZMA_STREAM_END)
{
return(cTotalRead);
}
// otherwise, reset outbuf to recv more decompressed data from liblzma, or decompress is finished
Trace.Assert(read_pos + (uint)_lzma_stream.avail_out <= BUFSIZE);
if (_lzma_stream.avail_out == UIntPtr.Zero && read_pos + (uint)_lzma_stream.avail_out == BUFSIZE)
{
_lzma_stream.next_out = _outbuf;
_lzma_stream.avail_out = (UIntPtr)BUFSIZE;
read_pos = 0;
}
// do decompress
ret = Native.lzma_code(_lzma_stream, action);
if (ret != lzma_ret.LZMA_OK && ret != lzma_ret.LZMA_STREAM_END)
{
throw new Exception($"lzma_code returns {ret}");
}
}
}
public static extern lzma_ret lzma_code(lzma_stream *strm, lzma_action action);
