protected override void Dispose(bool disposing)
{
if (_stream == null)
{
return;
}
try
{
// compress all remaining data
while (true)
{
// do compress, LZMA_FINISH action should return LZMA_OK or LZMA_STREAM_END on success
var ret = Native.lzma_code(_lzma_stream, lzma_action.LZMA_FINISH);
if (ret != lzma_ret.LZMA_STREAM_END && ret != lzma_ret.LZMA_OK)
{
throw new Exception($"lzma_code returns {ret}");
}
// write output buffer to underlying stream
if (_lzma_stream.avail_out == UIntPtr.Zero || ret == lzma_ret.LZMA_STREAM_END)
{
int size = (int)(BUFSIZE - (uint)_lzma_stream.avail_out);
var data = ArrayPool <byte> .Shared.Rent(size);
Marshal.Copy(_outbuf, data, 0, size);
_stream.Write(data, 0, size);
ArrayPool <byte> .Shared.Return(data);
// Reset next_out and avail_out.
_lzma_stream.next_out = _outbuf;
_lzma_stream.avail_out = (UIntPtr)BUFSIZE;
}
if (ret == lzma_ret.LZMA_STREAM_END)
{
break;
}
}
}
finally
{
Native.lzma_end(_lzma_stream);
Marshal.FreeHGlobal(_inbuf);
Marshal.FreeHGlobal(_outbuf);
_stream.Close();
_stream = null;
}
}
/// <summary>
/// learn from 01_compress_easy.c
/// </summary>
/// <param name="buffer"></param>
/// <param name="offset"></param>
/// <param name="count"></param>
public override void Write(byte[] buffer, int offset, int count)
{
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException(nameof(offset));
}
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
if (count + offset > buffer.Length)
{
throw new ArgumentOutOfRangeException(nameof(count), "offset+count > buffer.length");
}
if (count == 0)
{
return;
}
int bytesProcessed = 0;
while (true)
{
// Fill the input buffer if it is empty.
if (_lzma_stream.avail_in == UIntPtr.Zero)
{
int bytesToProcess = Math.Min(count - bytesProcessed, BUFSIZE);
if (bytesToProcess == 0)
{
break; // no more data to compress
}
_lzma_stream.next_in = _inbuf;
_lzma_stream.avail_in = (UIntPtr)bytesToProcess;
Marshal.Copy(buffer, offset + bytesProcessed, _inbuf, bytesToProcess);
bytesProcessed += bytesToProcess;
}
// do compress, RUN action should return LZMA_OK on success
var ret = Native.lzma_code(_lzma_stream, lzma_action.LZMA_RUN);
if (ret != lzma_ret.LZMA_OK)
{
throw new Exception($"lzma_code returns {ret}");
}
// check output buffer
if (_lzma_stream.avail_out == UIntPtr.Zero)
{
byte[] data = new byte[BUFSIZE];
Marshal.Copy(_outbuf, data, 0, data.Length);
_stream.Write(data, 0, data.Length);
// Reset next_out and avail_out.
_lzma_stream.next_out = _outbuf;
_lzma_stream.avail_out = (UIntPtr)BUFSIZE;
}
}
}
/// <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($"lzma_code returns {ret}");
}
}
}
/// <summary>
/// liblzma has provided lzma_stream_buffer_encode and lzma_stream_buffer_decode, but here I re-invent the wheel again...
/// </summary>
/// <param name="_lzma_stream"></param>
/// <param name="data"></param>
/// <param name="offset"></param>
/// <param name="count"></param>
/// <returns></returns>
private static byte[] CodeBuffer(lzma_stream _lzma_stream, byte[] data, int offset, int count)
{
const int BUFSIZE = 4096;
var outStream = new MemoryStream(BUFSIZE);
var inbuf = Marshal.AllocHGlobal(BUFSIZE);
var outbuf = Marshal.AllocHGlobal(BUFSIZE);
try
{
var action = lzma_action.LZMA_RUN;
_lzma_stream.next_in = inbuf;
_lzma_stream.avail_in = UIntPtr.Zero;
_lzma_stream.next_out = outbuf;
_lzma_stream.avail_out = (UIntPtr)BUFSIZE;
int read_pos = offset;
while (true)
{
if (_lzma_stream.avail_in == UIntPtr.Zero)
{
if (read_pos < offset + count)
{
int bytesToProcess = Math.Min(BUFSIZE, offset + count - read_pos);
_lzma_stream.next_in = inbuf;
_lzma_stream.avail_in = (UIntPtr)bytesToProcess;
Marshal.Copy(data, read_pos, inbuf, bytesToProcess);
read_pos += bytesToProcess;
Trace.Assert(read_pos <= offset + count);
}
if (read_pos == offset + count)
{
action = lzma_action.LZMA_FINISH;
}
}
var ret = Native.lzma_code(_lzma_stream, action);
if (_lzma_stream.avail_out == UIntPtr.Zero || ret == lzma_ret.LZMA_STREAM_END)
{
int write_size = BUFSIZE - (int)(uint)_lzma_stream.avail_out;
var tmp = new byte[write_size];
Marshal.Copy(outbuf, tmp, 0, write_size);
outStream.Write(tmp, 0, write_size);
_lzma_stream.next_out = outbuf;
_lzma_stream.avail_out = (UIntPtr)BUFSIZE;
}
if (ret != lzma_ret.LZMA_OK)
{
if (ret == lzma_ret.LZMA_STREAM_END)
{
break;
}
throw new Exception($"lzma_code returns {ret}");
}
}
}
finally
{
Marshal.FreeHGlobal(inbuf);
Marshal.FreeHGlobal(outbuf);
}
return(outStream.ToArray());
}