| using Lucene.Net.Util; |
| using System.IO; |
| using System.IO.Compression; |
| |
| namespace Lucene.Net.Documents |
| { |
| /* |
| * 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 |
| * |
| * http://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. |
| */ |
| |
| /// <summary> |
| /// Simple utility class providing static methods to |
| /// compress and decompress binary data for stored fields. |
| /// this class uses the <see cref="DeflateStream"/> |
| /// class to compress and decompress. |
| /// </summary> |
| public class CompressionTools |
| { |
| // Export only static methods |
| private CompressionTools() |
| { |
| } |
| |
| /// <summary> |
| /// Compresses the specified <see cref="byte"/> range using the |
| /// specified <paramref name="compressionLevel"/>. |
| /// </summary> |
| public static byte[] Compress(byte[] value, int offset, int length, CompressionLevel compressionLevel) |
| { |
| byte[] resultArray = null; |
| using (MemoryStream compressionMemoryStream = new MemoryStream()) |
| { |
| using (DeflateStream deflateStream = new DeflateStream(compressionMemoryStream, compressionLevel)) |
| { |
| |
| deflateStream.Write(value, offset, length); |
| } |
| resultArray = compressionMemoryStream.ToArray(); |
| } |
| return resultArray; |
| } |
| |
| /// <summary> |
| /// Compresses the specified <see cref="byte"/> range, with default <see cref="CompressionLevel.Optimal"/> level |
| /// </summary> |
| public static byte[] Compress(byte[] value, int offset, int length) |
| { |
| return Compress(value, offset, length, CompressionLevel.Optimal); |
| } |
| |
| /// <summary> |
| /// Compresses all <see cref="byte"/>s in the array, with default <see cref="CompressionLevel.Optimal"/> level </summary> |
| public static byte[] Compress(byte[] value) |
| { |
| return Compress(value, 0, value.Length, CompressionLevel.Optimal); |
| } |
| |
| /// <summary> |
| /// Compresses the <see cref="string"/> value, with default <see cref="CompressionLevel.Optimal"/> level </summary> |
| public static byte[] CompressString(string value) |
| { |
| return CompressString(value, CompressionLevel.Optimal); |
| } |
| |
| /// <summary> |
| /// Compresses the <see cref="string"/> value using the specified |
| /// <paramref name="compressionLevel"/>. |
| /// </summary> |
| public static byte[] CompressString(string value, CompressionLevel compressionLevel) |
| { |
| var result = new BytesRef(); |
| UnicodeUtil.UTF16toUTF8(value.ToCharArray(), 0, value.Length, result); |
| return Compress(result.Bytes, 0, result.Length, compressionLevel); |
| } |
| |
| /// <summary> |
| /// Decompress the <see cref="byte"/> array previously returned by |
| /// compress (referenced by the provided <see cref="BytesRef"/>) |
| /// </summary> |
| public static byte[] Decompress(BytesRef bytes) |
| { |
| return Decompress(bytes.Bytes, bytes.Offset, bytes.Length); |
| } |
| |
| /// <summary> |
| /// Decompress the <see cref="byte"/> array previously returned by |
| /// compress |
| /// </summary> |
| public static byte[] Decompress(byte[] value) |
| { |
| return Decompress(value, 0, value.Length); |
| } |
| |
| /// <summary> |
| /// Decompress the <see cref="byte"/> array previously returned by |
| /// compress |
| /// </summary> |
| public static byte[] Decompress(byte[] value, int offset, int length) |
| { |
| byte[] decompressedBytes = null; |
| |
| using (MemoryStream decompressedStream = new MemoryStream()) |
| { |
| using (MemoryStream compressedStream = new MemoryStream(value)) |
| { |
| using (DeflateStream dStream = new DeflateStream(compressedStream, CompressionMode.Decompress)) |
| { |
| dStream.CopyTo(decompressedStream); |
| } |
| } |
| decompressedBytes = decompressedStream.ToArray(); |
| } |
| |
| return decompressedBytes; |
| } |
| |
| /// <summary> |
| /// Decompress the <see cref="byte"/> array previously returned by |
| /// <see cref="CompressString(string)"/> back into a <see cref="string"/> |
| /// </summary> |
| public static string DecompressString(byte[] value) |
| { |
| return DecompressString(value, 0, value.Length); |
| } |
| |
| /// <summary> |
| /// Decompress the <see cref="byte"/> array previously returned by |
| /// <see cref="CompressString(string)"/> back into a <see cref="string"/> |
| /// </summary> |
| public static string DecompressString(byte[] value, int offset, int length) |
| { |
| byte[] bytes = Decompress(value, offset, length); |
| CharsRef result = new CharsRef(bytes.Length); |
| UnicodeUtil.UTF8toUTF16(bytes, 0, bytes.Length, result); |
| return new string(result.Chars, 0, result.Length); |
| } |
| |
| /// <summary> |
| /// Decompress the <see cref="byte"/> array (referenced by the provided <see cref="BytesRef"/>) |
| /// previously returned by <see cref="CompressString(string)"/> back into a <see cref="string"/> |
| /// </summary> |
| public static string DecompressString(BytesRef bytes) |
| { |
| return DecompressString(bytes.Bytes, bytes.Offset, bytes.Length); |
| } |
| } |
| } |