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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
}
}
来源：http://www.mostlylucid.co.uk/archive/2004/04/06/958.aspx
