FillInValue(Ice.OutputStream os, int pos, int value) => os.RewriteInt(value, pos);
public static Ice.OutputStream?Compress(Ice.OutputStream stream, int headerSize, int compressionLevel)
{
Debug.Assert(Supported());
// Compress the message body, but not the header.
int uncompressedLen = stream.Size - headerSize;
byte[] compressed = new byte[(int)((uncompressedLen * 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);
try
{
_compressInit(ref bzStream, compressionLevel, 0, 0);
System.Collections.Generic.IList <ArraySegment <byte> > data = stream.GetUnderlyingBuffer();
Debug.Assert(data[0].Offset == 0);
data[0] = data[0].Slice(headerSize);
int rc = BzRunOk;
for (int i = 0; rc == BzRunOk && 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 = _compress(ref bzStream, BzRun);
}while (rc == BzRunOk && bzStream.AvailIn > 0);
segmentHandle.Free();
}
if (rc != BzRunOk)
{
throw new Ice.CompressionException($"Bzip2 compress run failed {GetBZ2Error(rc)}");
}
do
{
rc = _compress(ref bzStream, BzFinish);
}while (rc == BzFinishOk);
if (rc != BzStreamEnd)
{
throw new Ice.CompressionException($"Bzip2 compress finish failed {GetBZ2Error(rc)}");
}
int compressedLen = compressed.Length - (int)bzStream.AvailOut;
// Don't bother if the compressed data is larger than the uncompressed data.
if (compressedLen >= uncompressedLen)
{
return(null);
}
// Copy the header from the uncompressed stream to the compressed one,
// we use headerSize + 4 to ensure there is room for the size of the
// uncompressed stream in the first segment.
Debug.Assert(data.Count > 0 && data[0].Count > headerSize + 4);
var r = new Ice.OutputStream(stream.Communicator, stream.Encoding,
data[0].Array.AsSpan(0, headerSize + 4).ToArray());
// Add the size of the uncompressed stream before the message body.
r.RewriteInt(stream.Size, new Ice.OutputStream.Position(0, headerSize));
r.WritePayload(new ArraySegment <byte>(compressed, 0, compressedLen));
return(r);
}
finally
{
_compressEnd(ref bzStream);
compressedHandle.Free();
}
}