/// <summary> /// Decompress a byte array. /// </summary> /// <param name="source">The <see cref="Byte"/> array to decompress.</param> /// <param name="length">The number of bytes to read into the byte array for compression.</param> /// <param name="startIndex">An <see cref="Int32"/> representing the start index of the byte array.</param> /// <returns>A decompressed <see cref="Byte"/> array.</returns> public static byte[] Decompress(this byte[] source, int startIndex, int length) { const byte CompressionStrengthMask = (byte)(Bits.Bit00 | Bits.Bit01); // Unmask compression strength from first buffer byte CompressionStrength strength = (CompressionStrength)(source[startIndex] & CompressionStrengthMask); if (strength == CompressionStrength.NoCompression) { // No compression was applied to original buffer, return specified portion of the buffer return source.BlockCopy(startIndex + 1, length - 1); } else { // Create a new decompression deflater MemoryStream compressedData = new MemoryStream(source, startIndex + 1, length - 1); DeflateStream inflater = new DeflateStream(compressedData, CompressionMode.Decompress); int compressionDepth = (source[startIndex] & ~CompressionStrengthMask) >> 2; // Read uncompressed data byte[] destination = inflater.ReadStream(); // When user requests muli-pass compression, there may be multiple compression passes on a buffer, // so we cycle through the needed uncompressions to get back to the original data if (strength == CompressionStrength.MultiPass && compressionDepth > 0) return destination.Decompress(); else return destination; } }