/// <summary>Compresses input buffer into self-contained package.</summary>
/// <param name="source">Input buffer.</param>
/// <param name="sourceLength">Length of input data.</param>
/// <param name="level">Compression level.</param>
/// <returns>Output buffer.</returns>
public static unsafe byte[] Pickle(
byte *source, int sourceLength, LZ4Level level = LZ4Level.L00_FAST)
{
if (sourceLength <= 0)
{
return(Mem.Empty);
}
var targetLength = sourceLength - 1;
var target = (byte *)Mem.Alloc(sourceLength);
try
{
var encodedLength = LZ4Codec.Encode(
source, sourceLength, target, targetLength, level);
return(encodedLength <= 0
? PickleV0(source, sourceLength, sourceLength)
: PickleV0(target, encodedLength, sourceLength));
}
finally
{
Mem.Free(target);
}
}
private void WriteFrame()
{
Stash32(0x184D2204);
FlushStash();
const int versionCode = 0x01;
var blockChaining = _descriptor.Chaining;
var blockChecksum = _descriptor.BlockChecksum;
var contentChecksum = _descriptor.ContentChecksum;
var hasContentSize = _descriptor.ContentLength.HasValue;
var hasDictionary = _descriptor.Dictionary.HasValue;
var FLG =
(versionCode << 6) |
((blockChaining ? 0 : 1) << 5) |
((blockChecksum ? 1 : 0) << 4) |
((hasContentSize ? 1 : 0) << 3) |
((contentChecksum ? 1 : 0) << 2) |
(hasDictionary ? 1 : 0);
var blockSize = _descriptor.BlockSize;
var BD = MaxBlockSizeCode(blockSize) << 4;
Stash16((ushort)((FLG & 0xFF) | (BD & 0xFF) << 8));
if (hasContentSize)
{
throw NotImplemented(
"ContentSize feature is not implemented"); // Write64(contentSize);
}
if (hasDictionary)
{
throw NotImplemented(
"Predefined dictionaries feature is not implemented"); // Write32(dictionaryId);
}
var HC = (byte)(XXH32.DigestOf(_buffer16, 0, _index16) >> 8);
Stash8(HC);
FlushStash();
_encoder = CreateEncoder();
_buffer = new byte[LZ4Codec.MaximumOutputSize(blockSize)];
}
/// <inheritdoc />
public int Decode(byte *source, int length, int blockSize = 0)
{
ThrowIfDisposed();
if (blockSize <= 0)
{
blockSize = _blockSize;
}
if (blockSize > _blockSize)
{
throw new InvalidOperationException();
}
var decoded = LZ4Codec.Decode(source, length, _outputBuffer, _outputLength);
if (decoded < 0)
{
throw new InvalidOperationException();
}
_outputIndex = decoded;
return(_outputIndex);
}