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// <copyright>
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
namespace System.ServiceModel.Channels
{
using System;
using System.IO;
using System.IO.Compression;
internal static class MessageEncoderCompressionHandler
{
internal const string GZipContentEncoding = "gzip";
internal const string DeflateContentEncoding = "deflate";
private const int DecompressBlockSize = 1024;
internal static void DecompressBuffer(ref ArraySegment<byte> buffer, BufferManager bufferManager, CompressionFormat compressionFormat, long maxReceivedMessageSize)
{
MemoryStream memoryStream = new MemoryStream(buffer.Array, buffer.Offset, buffer.Count);
int maxDecompressedSize = (int)Math.Min(maxReceivedMessageSize, int.MaxValue);
using (BufferManagerOutputStream bufferedOutStream = new BufferManagerOutputStream(SR.MaxReceivedMessageSizeExceeded, 1024, maxDecompressedSize, bufferManager))
{
bufferedOutStream.Write(buffer.Array, 0, buffer.Offset);
byte[] tempBuffer = bufferManager.TakeBuffer(DecompressBlockSize);
try
{
using (Stream ds = compressionFormat == CompressionFormat.GZip ?
(Stream)new GZipStream(memoryStream, CompressionMode.Decompress) :
(Stream)new DeflateStream(memoryStream, CompressionMode.Decompress))
{
while (true)
{
int bytesRead = ds.Read(tempBuffer, 0, DecompressBlockSize);
if (bytesRead > 0)
{
bufferedOutStream.Write(tempBuffer, 0, bytesRead);
}
else
{
break;
}
}
}
}
finally
{
bufferManager.ReturnBuffer(tempBuffer);
}
int length = 0;
byte[] decompressedBytes = bufferedOutStream.ToArray(out length);
bufferManager.ReturnBuffer(buffer.Array);
buffer = new ArraySegment<byte>(decompressedBytes, buffer.Offset, length - buffer.Offset);
}
}
internal static void CompressBuffer(ref ArraySegment<byte> buffer, BufferManager bufferManager, CompressionFormat compressionFormat)
{
using (BufferManagerOutputStream bufferedOutStream = new BufferManagerOutputStream(SR.MaxSentMessageSizeExceeded, 1024, int.MaxValue, bufferManager))
{
bufferedOutStream.Write(buffer.Array, 0, buffer.Offset);
using (Stream ds = compressionFormat == CompressionFormat.GZip ?
(Stream)new GZipStream(bufferedOutStream, CompressionMode.Compress, true) :
(Stream)new DeflateStream(bufferedOutStream, CompressionMode.Compress, true))
{
ds.Write(buffer.Array, buffer.Offset, buffer.Count);
}
int length = 0;
byte[] compressedBytes = bufferedOutStream.ToArray(out length);
bufferManager.ReturnBuffer(buffer.Array);
buffer = new ArraySegment<byte>(compressedBytes, buffer.Offset, length - buffer.Offset);
}
}
internal static Stream GetDecompressStream(Stream compressedStream, CompressionFormat compressionFormat)
{
return compressionFormat == CompressionFormat.GZip ?
(Stream)new GZipStream(compressedStream, CompressionMode.Decompress, false) :
(Stream)new DeflateStream(compressedStream, CompressionMode.Decompress, false);
}
internal static Stream GetCompressStream(Stream uncompressedStream, CompressionFormat compressionFormat)
{
return compressionFormat == CompressionFormat.GZip ?
(Stream)new GZipStream(uncompressedStream, CompressionMode.Compress, true) :
(Stream)new DeflateStream(uncompressedStream, CompressionMode.Compress, true);
}
}
}
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