internal static ArraySegment <byte> Decompress(ArraySegment <byte> compressed, int headerSize, int messageSizeMax)
{
Debug.Assert(IsLoaded);
int decompressedSize = InputStream.ReadInt(compressed.AsSpan(headerSize, 4));
if (decompressedSize <= headerSize)
{
throw new InvalidDataException(
$"received compressed ice1 frame with a decompressed size of only {decompressedSize} bytes");
}
if (decompressedSize > messageSizeMax)
{
throw new InvalidDataException(
$"decompressed size of {decompressedSize} bytes is greater than Ice.MessageSizeMax value");
}
byte[] decompressed = new byte[decompressedSize];
// Prevent GC from moving the byte array, this allow to take the object address
// and pass it to bzip2 calls.
var decompressedHandle = GCHandle.Alloc(decompressed, GCHandleType.Pinned);
var compressedHandle = GCHandle.Alloc(compressed.Array, GCHandleType.Pinned);
var bzStream = new BZStream(decompressedHandle.AddrOfPinnedObject() + headerSize,
(uint)(decompressedSize - headerSize));
BzStatus rc;
try
{
rc = (BzStatus)BZ2_bzDecompressInit(ref bzStream, 0, 0);
if (rc != BzStatus.Ok)
{
throw new TransportException($"bzip2 decompression failed: {rc}");
}
bzStream.NextIn = compressedHandle.AddrOfPinnedObject() + compressed.Offset + headerSize + 4;
bzStream.AvailIn = (uint)(compressed.Count - headerSize - 4);
rc = (BzStatus)BZ2_bzDecompress(ref bzStream);
if (rc != BzStatus.StreamEnd)
{
throw new TransportException($"bzip2 decompression failed: {rc}");
}
}
finally
{
rc = (BzStatus)BZ2_bzDecompressEnd(ref bzStream);
Debug.Assert(rc == BzStatus.Ok);
decompressedHandle.Free();
compressedHandle.Free();
}
compressed.AsSpan(0, headerSize).CopyTo(decompressed);
return(decompressed);
}
private static extern int BZ2_bzDecompressEnd(ref BZStream stream);
private static extern int BZ2_bzDecompressInit(ref BZStream stream, int verbosity, int small);
private static extern int BZ2_bzCompress(ref BZStream stream, int action);
private static extern int BZ2_bzCompressInit(ref BZStream stream, int blockSize100k, int verbosity,
int workFactor);
internal static List <ArraySegment <byte> >?Compress(
List <ArraySegment <byte> > data, int size, int headerSize, int compressionLevel)
{
Debug.Assert(IsLoaded);
// Compress the frame body, but not the header.
int decompressedLen = size - headerSize;
// Compress the frame body, but not the header.
byte[] compressed = new byte[(int)((decompressedLen * 1.01) + 600)];
// Prevent GC from moving the byte array, this allow to take the object address and pass it to bzip2 calls.
var compressedHandle = GCHandle.Alloc(compressed, GCHandleType.Pinned);
var bzStream = new BZStream(compressedHandle.AddrOfPinnedObject(), (uint)compressed.Length);
ArraySegment <byte> headerSegment = data[0];
BzStatus rc;
try
{
rc = (BzStatus)BZ2_bzCompressInit(ref bzStream, compressionLevel, 0, 0);
if (rc != BzStatus.Ok)
{
throw new TransportException($"bzip2 compression failed: {rc}");
}
// Slice the first segment to skip the header, the header is never compressed
Debug.Assert(headerSegment.Offset == 0);
data[0] = headerSegment.Slice(headerSize);
rc = BzStatus.RunOk;
for (int i = 0; rc == BzStatus.RunOk && i < data.Count; i++)
{
ArraySegment <byte> segment = data[i];
var segmentHandle = GCHandle.Alloc(segment.Array, GCHandleType.Pinned);
bzStream.NextIn = segmentHandle.AddrOfPinnedObject() + segment.Offset;
bzStream.AvailIn = (uint)segment.Count;
Debug.Assert(bzStream.AvailIn > 0);
do
{
rc = (BzStatus)BZ2_bzCompress(ref bzStream, (int)BzAction.Run);
}while (rc == BzStatus.RunOk && bzStream.AvailIn > 0);
segmentHandle.Free();
}
if (rc != BzStatus.RunOk)
{
throw new TransportException($"bzip2 compression failed: {rc}");
}
do
{
rc = (BzStatus)BZ2_bzCompress(ref bzStream, (int)BzAction.Finish);
}while (rc == BzStatus.FinishOk);
if (rc != BzStatus.StreamEnd)
{
throw new TransportException($"bzip2 compression failed: {rc}");
}
int compressedLen = compressed.Length - (int)bzStream.AvailOut;
// Don't bother if the compressed data is larger than the decompressed data.
if (compressedLen >= decompressedLen)
{
return(null);
}
// Copy the header from the decompressed stream to the compressed one, we use headerSize + 4 to ensure
// there is room for the size of the decompressed stream in the first segment.
ArraySegment <byte> compressedHeader = new byte[headerSize + 4];
headerSegment.AsSpan(0, headerSize).CopyTo(compressedHeader);
int compressedSize = compressedLen + compressedHeader.Count;
// Write the compression status and the size of the compressed stream into the header.
compressedHeader[9] = 2;
OutputStream.WriteInt(compressedSize, compressedHeader.AsSpan(10, 4));
// Write the compression status and size of the compressed stream into the header of the decompressed
// stream -- we need this to trace requests correctly.
headerSegment[9] = 2;
OutputStream.WriteInt(compressedSize, headerSegment.AsSpan(10, 4));
// Add the size of the decompressed stream before the frame body.
OutputStream.WriteInt(size, compressedHeader.AsSpan(headerSize, 4));
return(new List <ArraySegment <byte> >(2)
{
compressedHeader,
new ArraySegment <byte>(compressed, 0, compressedLen)
});
}
finally
{
// Restore the first segment that was Sliced above to skip the header
data[0] = headerSegment;
rc = (BzStatus)BZ2_bzCompressEnd(ref bzStream);
Debug.Assert(rc == BzStatus.Ok);
compressedHandle.Free();
}
}
