| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * https://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| using System; |
| using System.IO; |
| |
| namespace Avro.File.Snappy |
| { |
| /// <summary> |
| /// Implements Snappy compression and decompression. |
| /// </summary> |
| public class SnappyCodec : Codec |
| { |
| /// <inheritdoc/> |
| /// <inheritdoc/> |
| public override byte[] Compress(byte[] uncompressedData) |
| { |
| using (MemoryStream outputStream = new MemoryStream()) |
| { |
| byte[] compressedData = IronSnappy.Snappy.Encode(uncompressedData); |
| outputStream.Write(compressedData, 0, compressedData.Length); |
| |
| var crc = ByteSwap(Crc32.Compute(uncompressedData)); |
| outputStream.Write(BitConverter.GetBytes(crc), 0, 4); |
| |
| return outputStream.ToArray(); |
| } |
| } |
| |
| /// <inheritdoc/> |
| public override void Compress(MemoryStream inputStream, MemoryStream outputStream) |
| { |
| inputStream.Position = 0; |
| |
| byte[] uncompressedData = inputStream.ToArray(); |
| byte[] compressedData = IronSnappy.Snappy.Encode(uncompressedData); |
| |
| outputStream.SetLength(0); |
| |
| outputStream.Write(compressedData, 0, compressedData.Length); |
| |
| var crc = ByteSwap(Crc32.Compute(uncompressedData)); |
| outputStream.Write(BitConverter.GetBytes(crc), 0, 4); |
| } |
| |
| /// <inheritdoc/> |
| public override byte[] Decompress(byte[] compressedData, int blockLength) |
| { |
| byte[] uncompressedData = IronSnappy.Snappy.Decode(compressedData.AsSpan(0, blockLength - 4)); |
| |
| return ByteSwap(Crc32.Compute(uncompressedData)) == BitConverter.ToUInt32(compressedData, blockLength - 4) ? |
| uncompressedData : |
| throw new IOException("Checksum failure"); |
| } |
| |
| private static uint ByteSwap(uint word) |
| { |
| return ((word >> 24) & 0x000000FF) | ((word >> 8) & 0x0000FF00) | ((word << 8) & 0x00FF0000) | ((word << 24) & 0xFF000000); |
| } |
| |
| /// <inheritdoc/> |
| public override string GetName() |
| { |
| return DataFileConstants.SnappyCodec; |
| } |
| |
| /// <inheritdoc/> |
| public override bool Equals(object other) |
| { |
| return this == other || GetType().Name == other.GetType().Name; |
| } |
| |
| /// <inheritdoc/> |
| public override int GetHashCode() |
| { |
| return GetName().GetHashCode(); |
| } |
| } |
| } |