public static int GetBlockSize(LZ4BlockSize blockSizeType)
{
switch (blockSizeType)
{
case LZ4BlockSize.Max64Kb:
return(64 * KB);
case LZ4BlockSize.Max256Kb:
return(256 * KB);
case LZ4BlockSize.Max1Mb:
return(1 * MB);
case LZ4BlockSize.Max4Mb:
return(4 * MB);
}
return(-1);
}
public static int GetBlockSize(LZ4BlockSize blockSizeType)
{
switch (blockSizeType)
{
case LZ4BlockSize.Max64Kb:
return 64*KB;
case LZ4BlockSize.Max256Kb:
return 256*KB;
case LZ4BlockSize.Max1Mb:
return 1*MB;
case LZ4BlockSize.Max4Mb:
return 4*MB;
}
return -1;
}
//readonly unsafe LZ4Preferences* _prefs;
#endregion Private Members
#region Ctor
/// <summary>
/// Initializes a new instance of the <see cref="LZ4Stream"/> class.
/// </summary>
/// <param name="baseStream">The base stream.</param>
/// <param name="mode">The compression mode</param>
/// <param name="level">The compression level. Relevant for <see cref="CompressionMode.Compress"/></param>
/// <param name="blockSize">Size of the block.</param>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="LZ4Exception">
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">mode</exception>
/// <exception cref="OutOfMemoryException">There is insufficient memory to satisfy the request.</exception>
/// <exception cref="ArgumentException">Steam compression mode contradicts base-stream read/write availability</exception>
public unsafe LZ4Stream(Stream baseStream, CompressionMode mode, Lz4CompressionLevel level = Lz4CompressionLevel.Fastest, LZ4BlockSize blockSize = LZ4BlockSize.Max4Mb)
{
if (baseStream == null) throw new ArgumentNullException(nameof(baseStream));
if (mode == CompressionMode.Compress && !baseStream.CanWrite)
throw new ArgumentException("stream is set to compress, but base-stream cannot be written to", nameof(baseStream));
if (mode == CompressionMode.Decompress && !baseStream.CanRead)
throw new ArgumentException("stream is set to decompress, but base-stream cannot be read from", nameof(baseStream));
Contract.EndContractBlock();
_baseStream = baseStream;
_mode = mode;
void* ctx;
size_t rc;
switch (mode) {
case CompressionMode.Compress:
rc = LZ4F_createCompressionContext(&ctx, Lz4Version);
_ctx = ctx;
if (LZ4F_isError(rc))
throw new LZ4Exception(rc);
LZ4Preferences prefs;
prefs.AutoFlush = Lz4AutoFlush.Enabled;
prefs.CompressionLevel = level;
prefs.FrameInfo.BlockMode = LZ4BlockMode.Independent;
prefs.FrameInfo.BlockSize = blockSize;
prefs.FrameInfo.ContentChecksum = LZ4ContentChecksum.Enabled;
MaxInputBufferSize = GetBlockSize(blockSize);
_dstBuffer = new NativeBuffer(LZ4F_compressFrameBound((IntPtr) MaxInputBufferSize).ToInt32());
var headerSize = LZ4F_compressBegin(_ctx, _dstBuffer.Ptr, (IntPtr) _dstBuffer.Size, &prefs);
if (LZ4F_isError(headerSize))
throw new LZ4Exception(headerSize,
$"File header generation failed: {GetErrorName(headerSize)}");
_baseStream.Write(_dstBuffer.Buffer, 0, headerSize.ToInt32());
break;
case CompressionMode.Decompress:
rc = LZ4F_createDecompressionContext(&ctx, Lz4Version);
_ctx = ctx;
if (LZ4F_isError(rc))
throw new LZ4Exception(rc);
_srcBuffer = new NativeBuffer(DECOMPRESSION_BUFFER_SIZE);
baseStream.Read(_srcBuffer.Buffer, 0, sizeof (int));
var outSize = 0UL;
var inSize = (ulong) sizeof (int);
var frameHeader = stackalloc byte[MAX_FRAME_HEADER_SIZE];
rc = LZ4F_decompress(_ctx, frameHeader, (IntPtr*) &outSize, _srcBuffer.Ptr, (IntPtr*) &inSize);
if (LZ4F_isError(rc))
throw new LZ4Exception(rc);
_nextSizeToRead = (ulong) rc;
break;
default:
throw new ArgumentOutOfRangeException(nameof(mode), $"Unsupported mode: {mode}");
}
}
//readonly unsafe LZ4Preferences* _prefs;
#endregion Private Members
#region Ctor
/// <summary>
/// Initializes a new instance of the <see cref="LZ4Stream"/> class.
/// </summary>
/// <param name="baseStream">The base stream.</param>
/// <param name="mode">The compression mode</param>
/// <param name="level">The compression level. Relevant for <see cref="CompressionMode.Compress"/></param>
/// <param name="blockSize">Size of the block.</param>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="LZ4Exception">
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">mode</exception>
/// <exception cref="OutOfMemoryException">There is insufficient memory to satisfy the request.</exception>
/// <exception cref="ArgumentException">Steam compression mode contradicts base-stream read/write availability</exception>
public unsafe LZ4Stream(Stream baseStream, CompressionMode mode, Lz4CompressionLevel level = Lz4CompressionLevel.Fastest, LZ4BlockSize blockSize = LZ4BlockSize.Max4Mb)
{
if (baseStream == null)
{
throw new ArgumentNullException(nameof(baseStream));
}
if (mode == CompressionMode.Compress && !baseStream.CanWrite)
{
throw new ArgumentException("stream is set to compress, but base-stream cannot be written to", nameof(baseStream));
}
if (mode == CompressionMode.Decompress && !baseStream.CanRead)
{
throw new ArgumentException("stream is set to decompress, but base-stream cannot be read from", nameof(baseStream));
}
Contract.EndContractBlock();
_baseStream = baseStream;
_mode = mode;
void * ctx;
size_t rc;
switch (mode)
{
case CompressionMode.Compress:
rc = LZ4F_createCompressionContext(&ctx, Lz4Version);
_ctx = ctx;
if (LZ4F_isError(rc))
{
throw new LZ4Exception(rc);
}
LZ4Preferences prefs;
prefs.AutoFlush = Lz4AutoFlush.Enabled;
prefs.CompressionLevel = level;
prefs.FrameInfo.BlockMode = LZ4BlockMode.Independent;
prefs.FrameInfo.BlockSize = blockSize;
prefs.FrameInfo.ContentChecksum = LZ4ContentChecksum.Enabled;
MaxInputBufferSize = GetBlockSize(blockSize);
_dstBuffer = new NativeBuffer(LZ4F_compressFrameBound((IntPtr)MaxInputBufferSize).ToInt32());
var headerSize = LZ4F_compressBegin(_ctx, _dstBuffer.Ptr, (IntPtr)_dstBuffer.Size, &prefs);
if (LZ4F_isError(headerSize))
{
throw new LZ4Exception(headerSize,
$"File header generation failed: {GetErrorName(headerSize)}");
}
_baseStream.Write(_dstBuffer.Buffer, 0, headerSize.ToInt32());
break;
case CompressionMode.Decompress:
rc = LZ4F_createDecompressionContext(&ctx, Lz4Version);
_ctx = ctx;
if (LZ4F_isError(rc))
{
throw new LZ4Exception(rc);
}
_srcBuffer = new NativeBuffer(DECOMPRESSION_BUFFER_SIZE);
baseStream.Read(_srcBuffer.Buffer, 0, sizeof(int));
var outSize = 0UL;
var inSize = (ulong)sizeof(int);
var frameHeader = stackalloc byte[MAX_FRAME_HEADER_SIZE];
rc = LZ4F_decompress(_ctx, frameHeader, (IntPtr *)&outSize, _srcBuffer.Ptr, (IntPtr *)&inSize);
if (LZ4F_isError(rc))
{
throw new LZ4Exception(rc);
}
_nextSizeToRead = (ulong)rc;
break;
default:
throw new ArgumentOutOfRangeException(nameof(mode), $"Unsupported mode: {mode}");
}
}
