使用 SharpZipLib 进行压缩的辅助类，简化压缩字节数组和字符串的操作。
using System;
using System.Text;
using System.IO;
using ICSharpCode.SharpZipLib.BZip2;
using ICSharpCode.SharpZipLib.GZip;
using ICSharpCode.SharpZipLib.Zip;
namespace Compression
{
/// <summary>
/// 压缩方式。
/// </summary>
public enum CompressionType
{
GZip,
BZip2,
Zip
}
/// <summary>
/// 使用 SharpZipLib 进行压缩的辅助类，简化压缩字节数组和字符串的操作。
/// </summary>
public class CompressionHelper
{
/// <summary>
/// 压缩供应者，默认为 GZip。
/// </summary>
public static CompressionType CompressionProvider = CompressionType.GZip;
#region Public methods
/// <summary>
/// 从原始字节数组生成已压缩的字节数组。
/// </summary>
/// <param name="bytesToCompress">原始字节数组。</param>
/// <returns>返回已压缩的字节数组</returns>
public static byte[] Compress( byte[] bytesToCompress )
{
MemoryStream ms = new MemoryStream();
Stream s = OutputStream( ms );
s.Write( bytesToCompress, 0, bytesToCompress.Length );
s.Close();
return ms.ToArray();
}
/// <summary>
/// 从原始字符串生成已压缩的字符串。
/// </summary>
/// <param name="stringToCompress">原始字符串。</param>
/// <returns>返回已压缩的字符串。</returns>
public static string Compress( string stringToCompress )
{
byte[] compressedData = CompressToByte( stringToCompress );
string strOut = Convert.ToBase64String( compressedData );
return strOut;
}
/// <summary>
/// 从原始字符串生成已压缩的字节数组。
/// </summary>
/// <param name="stringToCompress">原始字符串。</param>
/// <returns>返回已压缩的字节数组。</returns>
public static byte[] CompressToByte( string stringToCompress )
{
byte[] bytData = Encoding.Unicode.GetBytes( stringToCompress );
return Compress( bytData );
}
/// <summary>
/// 从已压缩的字符串生成原始字符串。
/// </summary>
/// <param name="stringToDecompress">已压缩的字符串。</param>
/// <returns>返回原始字符串。</returns>
public string DeCompress( string stringToDecompress )
{
string outString = string.Empty;
if ( stringToDecompress == null )
{
throw new ArgumentNullException("stringToDecompress", "You tried to use an empty string");
}
try
{
byte[] inArr = Convert.FromBase64String(stringToDecompress.Trim());
outString = Encoding.Unicode.GetString(DeCompress(inArr));
}
catch (NullReferenceException nEx)
{
return nEx.Message;
}
return outString;
}
/// <summary>
/// 从已压缩的字节数组生成原始字节数组。
/// </summary>
/// <param name="bytesToDecompress">已压缩的字节数组。</param>
/// <returns>返回原始字节数组。</returns>
public static byte[] DeCompress( byte[] bytesToDecompress )
{
byte[] writeData = new byte[4096];
Stream s2 = InputStream( new MemoryStream( bytesToDecompress ) );
MemoryStream outStream = new MemoryStream();
while (true)
{
int size = s2.Read( writeData, 0, writeData.Length );
if ( size > 0 )
{
outStream.Write( writeData, 0, size );
}
else
{
break;
}
}
s2.Close();
byte[] outArr = outStream.ToArray();
outStream.Close();
return outArr;
}
#endregion
#region Private methods
/// <summary>
/// 从给定的流生成压缩输出流。
/// </summary>
/// <param name="inputStream">原始流。</param>
/// <returns>返回压缩输出流。</returns>
private static Stream OutputStream( Stream inputStream )
{
switch ( CompressionProvider )
{
case CompressionType.BZip2:
return new BZip2OutputStream( inputStream );
case CompressionType.GZip:
return new GZipOutputStream( inputStream );
case CompressionType.Zip:
return new ZipOutputStream( inputStream );
default:
return new GZipOutputStream( inputStream );
}
}
/// <summary>
/// 从给定的流生成压缩输入流。
/// </summary>
/// <param name="inputStream">原始流。</param>
/// <returns>返回压缩输入流。</returns>
private static Stream InputStream( Stream inputStream )
{
switch (CompressionProvider)
{
case CompressionType.BZip2:
return new BZip2InputStream(inputStream);
case CompressionType.GZip:
return new GZipInputStream(inputStream);
case CompressionType.Zip:
return new ZipInputStream(inputStream);
default:
return new GZipInputStream(inputStream);
}
}
#endregion
}
}
