using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.IO;
using Microsoft.Win32;
using System.IO.Compression;
using System.Runtime.Serialization.Formatters.Binary;
namespace AIMSCommon
{
/// <summary>
/// 压缩文本、字节或者文件的压缩辅助类
/// </summary>
public class GZipHelper
{
/// <summary>
/// 压缩字符串
/// </summary>
/// <param name="text"></param>
/// <returns></returns>
public static string Compress(string text)
{
// convert text to bytes
byte[] buffer = Encoding.UTF8.GetBytes(text);
// get a stream
MemoryStream ms = new MemoryStream();
// get ready to zip up our stream
using (GZipStream zip = new GZipStream(ms, CompressionMode.Compress, true))
{
// compress the data into our buffer
zip.Write(buffer, 0, buffer.Length);
}
// reset our position in compressed stream to the start
ms.Position = 0;
// get the compressed data
byte[] compressed = ms.ToArray();
ms.Read(compressed, 0, compressed.Length);
// prepare final data with header that indicates length
byte[] gzBuffer = new byte[compressed.Length + 4];
//copy compressed data 4 bytes from start of final header
System.Buffer.BlockCopy(compressed, 0, gzBuffer, 4, compressed.Length);
// copy header to first 4 bytes
System.Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gzBuffer, 0, 4);
// convert back to string and return
return Convert.ToBase64String(gzBuffer);
}
/// <summary>
/// 解压字符串
/// </summary>
/// <param name="compressedText"></param>
/// <returns></returns>
public static string Uncompress(string compressedText)
{
// get string as bytes
byte[] gzBuffer = Convert.FromBase64String(compressedText);
// prepare stream to do uncompression
MemoryStream ms = new MemoryStream();
// get the length of compressed data
int msgLength = BitConverter.ToInt32(gzBuffer, 0);
// uncompress everything besides the header
ms.Write(gzBuffer, 4, gzBuffer.Length - 4);
// prepare final buffer for just uncompressed data
byte[] buffer = new byte[msgLength];
// reset our position in stream since we're starting over
ms.Position = 0;
// unzip the data through stream
GZipStream zip = new GZipStream(ms, CompressionMode.Decompress);
// do the unzip
zip.Read(buffer, 0, buffer.Length);
// convert back to string and return
return Encoding.UTF8.GetString(buffer);
}
public static T GZip<T>(Stream stream, CompressionMode mode) where T : Stream
{
byte[] writeData = new byte[4096];
T ms = default(T);
using (Stream sg = new GZipStream(stream, mode))
{
while (true)
{
Array.Clear(writeData, 0, writeData.Length);
int size = sg.Read(writeData, 0, writeData.Length);
if (size > 0)
{
ms.Write(writeData, 0, size);
}
else
{
break;
}
}
return ms;
}
}
/// <summary>
/// 压缩字节
/// </summary>
/// <param name="bytData"></param>
/// <returns></returns>
public static byte[] Compress(byte[] bytData)
{
using (MemoryStream stream = GZip<MemoryStream>(new MemoryStream(bytData), CompressionMode.Compress))
{
return stream.ToArray();
}
}
/// <summary>
/// 解压字节
/// </summary>
/// <param name="bytData"></param>
/// <returns></returns>
public static byte[] Decompress(byte[] bytData)
{
using (MemoryStream stream = GZip<MemoryStream>(new MemoryStream(bytData), CompressionMode.Decompress))
{
return stream.ToArray();
}
}
/// <summary>
/// 压缩文件
/// </summary>
/// <param name="sourceFile">源文件</param>
/// <param name="destinationFile">目标文件</param>
public static void CompressFile(string sourceFile, string destinationFile)
{
if (File.Exists(sourceFile) == false) //判断文件是否存在
throw new FileNotFoundException();
if (File.Exists(destinationFile) == false) //判断目标文件文件是否存在
FileHelper.DeleteFile(destinationFile);
//创建文件流和字节数组
byte[] buffer = null;
FileStream sourceStream = null;
FileStream destinationStream = null;
GZipStream compressedStream = null;
try
{
sourceStream = new FileStream(sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read);
buffer = new byte[sourceStream.Length];
//把文件流存放到字节数组中
int checkCounter = sourceStream.Read(buffer, 0, buffer.Length);
if (checkCounter != buffer.Length)
{
throw new ApplicationException();
}
destinationStream = new FileStream(destinationFile, FileMode.OpenOrCreate, FileAccess.Write);
//创建GzipStream实例,写入压缩的文件流
compressedStream = new GZipStream(destinationStream, CompressionMode.Compress, true);
compressedStream.Write(buffer, 0, buffer.Length);
}
finally
{
// Make sure we allways close all streams
if (sourceStream != null)
{ sourceStream.Close(); }
if (compressedStream != null)
{ compressedStream.Close(); }
if (destinationStream != null)
{ destinationStream.Close(); }
}
}
/// <summary>
/// 解压文件
/// </summary>
/// <param name="sourceFile">源文件</param>
/// <param name="destinationFile">目标文件</param>
public static void DecompressFile(string sourceFile, string destinationFile)
{
if (!File.Exists(sourceFile))
{
throw new FileNotFoundException();
}
FileStream stream = null;
FileStream stream2 = null;
GZipStream stream3 = null;
byte[] buffer = null;
try
{
stream = new FileStream(sourceFile, FileMode.Open);
stream3 = new GZipStream(stream, CompressionMode.Decompress, true);
buffer = new byte[4];
int num = ((int)stream.Length) - 4;
stream.Position = num;
stream.Read(buffer, 0, 4);
stream.Position = 0L;
byte[] buffer2 = new byte[BitConverter.ToInt32(buffer, 0) + 100];
int offset = 0;
int count = 0;
while (true)
{
int num5 = stream3.Read(buffer2, offset, 100);
if (num5 == 0)
{
break;
}
offset += num5;
count += num5;
}
stream2 = new FileStream(destinationFile, FileMode.Create);
stream2.Write(buffer2, 0, count);
stream2.Flush();
}
finally
{
if (stream != null)
{
stream.Close();
}
if (stream3 != null)
{
stream3.Close();
}
if (stream2 != null)
{
stream2.Close();
}
}
}
}
}