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Packages/com.tivadar.best.http/Runtime/HTTP/Response/Decompression/DeflateDecompressor.cs

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+using System;
+
+using Best.HTTP.Shared.Compression.Zlib;
+using Best.HTTP.Shared.Logger;
+using Best.HTTP.Shared.PlatformSupport.Memory;
+using Best.HTTP.Shared.Streams;
+
+namespace Best.HTTP.Response.Decompression
+{
+    public sealed class DeflateDecompressor : IDecompressor
+    {
+        private BufferPoolMemoryStream decompressorInputStream;
+        private BufferPoolMemoryStream decompressorOutputStream;
+        private DeflateStream decompressorStream;
+
+        private int MinLengthToDecompress = 256;
+
+        public static bool IsSupported = true;
+
+        public DeflateDecompressor(int minLengthToDecompress)
+        {
+            this.MinLengthToDecompress = minLengthToDecompress;
+        }
+
+        public (BufferSegment decompressed, bool releaseTheOld) Decompress(BufferSegment segment, bool forceDecompress, bool dataCanBeLarger, LoggingContext context)
+        {
+            if (decompressorInputStream == null)
+                decompressorInputStream = new BufferPoolMemoryStream(segment.Count);
+
+            if (segment.Data != null)
+                decompressorInputStream.Write(segment.Data, segment.Offset, segment.Count);
+
+            if (!forceDecompress && decompressorInputStream.Length < MinLengthToDecompress)
+                return (BufferSegment.Empty, true);
+
+            decompressorInputStream.Position = 0;
+
+            if (decompressorStream == null)
+            {
+                // Had to change from this
+                // _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.DEFLATE, leaveOpen);
+                // this this:
+                // _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.ZLIB, leaveOpen);
+                // Because there are two bytes in the header additionally to what the deflate flavor expects that the zlib one handles fine.
+                decompressorStream = new DeflateStream(decompressorInputStream,
+                                                    CompressionMode.Decompress,
+                                                    CompressionLevel.Default,
+                                                    true);
+                decompressorStream.FlushMode = FlushType.Sync;
+            }
+
+            if (decompressorOutputStream == null)
+                decompressorOutputStream = new BufferPoolMemoryStream();
+            decompressorOutputStream.SetLength(0);
+
+            byte[] copyBuffer = BufferPool.Get(1024, true);
+
+            int readCount;
+            int sumReadCount = 0;
+            while ((readCount = decompressorStream.Read(copyBuffer, 0, copyBuffer.Length)) != 0)
+            {
+                decompressorOutputStream.Write(copyBuffer, 0, readCount);
+                sumReadCount += readCount;
+            }
+
+            BufferPool.Release(copyBuffer);
+
+            // If no read is done (returned with any data) don't zero out the input stream, as it would delete any not yet used data.
+            if (sumReadCount > 0)
+                decompressorStream.SetLength(0);
+
+            byte[] result = decompressorOutputStream.ToArray(dataCanBeLarger, context);
+
+            return (new BufferSegment(result, 0, dataCanBeLarger ? (int)decompressorOutputStream.Length : result.Length), true);
+        }
+
+        ~DeflateDecompressor()
+        {
+            Dispose();
+        }
+
+        public void Dispose()
+        {
+            if (decompressorInputStream != null)
+                decompressorInputStream.Dispose();
+            decompressorInputStream = null;
+
+            if (decompressorOutputStream != null)
+                decompressorOutputStream.Dispose();
+            decompressorOutputStream = null;
+
+            if (decompressorStream != null)
+            {
+                // If the decompressor closed before receiving data, or it's incomplete, disposing (eg. closing) it
+                // throws an execption like this:
+                // "Missing or incomplete GZIP trailer. Expected 8 bytes, got 0."
+                try
+                {
+                    decompressorStream.Dispose();
+                }
+                catch
+                { }
+            }
+            decompressorStream = null;
+
+            GC.SuppressFinalize(this);
+        }
+    }
+}