前面介紹了六種.NET組件，其中有一種組件是寫文件的壓縮和解壓，現在介紹另一種文件的解壓縮組件SharpZipLib。在這個組件介紹系列中，只為簡單的介紹組件的背景和簡單的應用，讀者在閱讀時可以結合官網的相關介紹和在本地實際操作。
相關的組件功能非常強大，在筆者的介紹中只是提及到簡單的應用，需要了解更多的操作和特性，可以根據官網介紹，或者查看DLL文件的相關類和方法，以此來擴展相關的業務需要。
SharpZipLib是一個完全在C＃中為.NET平台編寫的Zip，GZip，Tar和BZip2庫。
一.SharpZipLib組件概述：
ziplib（SharpZipLib，以前的NZipLib）是一個完全在C＃為.NET平台編寫的Zip，GZip，Tar和BZip2庫。它實現為一個程序集（可安裝在GAC中），因此可以輕松地集成到其他項目（任何.NET語言）中。 #ziplib的創建者這樣說：“我已經將zip庫移植到C＃，因為我需要gzip / zip壓縮，我不想使用libzip.dll或類似的東西我想要的所有在純C＃“。
SharpZipLib官網提供的下載操作：.NET 1.1，.NET 2.0（3.5，4.0），.NET CF 1.0，.NET CF 2.0的裝配：下載237 KB，源代碼和示例下載708 KB；源代碼和示例下載708 KB；幫助文件下載1208 KB；
SharpZipLib是在GPL下發布，遵守開源協議。
二.SharpZipLib核心類和方法介紹：
以上簡單的介紹了SharpZipLib組件的相關背景，現在具體看一下該組件的相關核心類和方法：
1.ZipOutputStream類PutNextEntry()：
public void PutNextEntry(ZipEntry entry)
{
bool hasCrc;
if (entry == null)
{
throw new ArgumentNullException("entry");
}
if (this.entries == null)
{
throw new InvalidOperationException("ZipOutputStream was finished");
}
if (this.curEntry != null)
{
this.CloseEntry();
}
if (this.entries.Count == 0x7fffffff)
{
throw new ZipException("Too many entries for Zip file");
}
CompressionMethod compressionMethod = entry.CompressionMethod;
int defaultCompressionLevel = this.defaultCompressionLevel;
entry.Flags &= 0x800;
this.patchEntryHeader = false;
if (entry.Size == 0L)
{
entry.CompressedSize = entry.Size;
entry.Crc = 0L;
compressionMethod = CompressionMethod.Stored;
hasCrc = true;
}
else
{
hasCrc = (entry.Size >= 0L) && entry.HasCrc;
if (compressionMethod == CompressionMethod.Stored)
{
if (!hasCrc)
{
if (!base.CanPatchEntries)
{
compressionMethod = CompressionMethod.Deflated;
defaultCompressionLevel = 0;
}
}
else
{
entry.CompressedSize = entry.Size;
hasCrc = entry.HasCrc;
}
}
}
if (!hasCrc)
{
if (!base.CanPatchEntries)
{
entry.Flags |= 8;
}
else
{
this.patchEntryHeader = true;
}
}
if (base.Password != null)
{
entry.IsCrypted = true;
if (entry.Crc < 0L)
{
entry.Flags |= 8;
}
}
entry.Offset = this.offset;
entry.CompressionMethod = compressionMethod;
this.curMethod = compressionMethod;
this.sizePatchPos = -1L;
if ((this.useZip64_ == UseZip64.On) || ((entry.Size < 0L) && (this.useZip64_ == UseZip64.Dynamic)))
{
entry.ForceZip64();
}
this.WriteLeInt(0x4034b50);
this.WriteLeShort(entry.Version);
this.WriteLeShort(entry.Flags);
this.WriteLeShort((byte) entry.CompressionMethodForHeader);
this.WriteLeInt((int) entry.DosTime);
if (hasCrc)
{
this.WriteLeInt((int) entry.Crc);
if (entry.LocalHeaderRequiresZip64)
{
this.WriteLeInt(-1);
this.WriteLeInt(-1);
}
else
{
this.WriteLeInt(entry.IsCrypted ? (((int) entry.CompressedSize) + 12) : ((int) entry.CompressedSize));
this.WriteLeInt((int) entry.Size);
}
}
else
{
if (this.patchEntryHeader)
{
this.crcPatchPos = base.baseOutputStream_.Position;
}
this.WriteLeInt(0);
if (this.patchEntryHeader)
{
this.sizePatchPos = base.baseOutputStream_.Position;
}
if (entry.LocalHeaderRequiresZip64 || this.patchEntryHeader)
{
this.WriteLeInt(-1);
this.WriteLeInt(-1);
}
else
{
this.WriteLeInt(0);
this.WriteLeInt(0);
}
}
byte[] buffer = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if (buffer.Length > 0xffff)
{
throw new ZipException("Entry name too long.");
}
ZipExtraData extraData = new ZipExtraData(entry.ExtraData);
if (entry.LocalHeaderRequiresZip64)
{
extraData.StartNewEntry();
if (hasCrc)
{
extraData.AddLeLong(entry.Size);
extraData.AddLeLong(entry.CompressedSize);
}
else
{
extraData.AddLeLong(-1L);
extraData.AddLeLong(-1L);
}
extraData.AddNewEntry(1);
if (!extraData.Find(1))
{
throw new ZipException("Internal error cant find extra data");
}
if (this.patchEntryHeader)
{
this.sizePatchPos = extraData.CurrentReadIndex;
}
}
else
{
extraData.Delete(1);
}
if (entry.AESKeySize > 0)
{
AddExtraDataAES(entry, extraData);
}
byte[] entryData = extraData.GetEntryData();
this.WriteLeShort(buffer.Length);
this.WriteLeShort(entryData.Length);
if (buffer.Length > 0)
{
base.baseOutputStream_.Write(buffer, 0, buffer.Length);
}
if (entry.LocalHeaderRequiresZip64 && this.patchEntryHeader)
{
this.sizePatchPos += base.baseOutputStream_.Position;
}
if (entryData.Length > 0)
{
base.baseOutputStream_.Write(entryData, 0, entryData.Length);
}
this.offset += (30 + buffer.Length) + entryData.Length;
if (entry.AESKeySize > 0)
{
this.offset += entry.AESOverheadSize;
}
this.curEntry = entry;
this.crc.Reset();
if (compressionMethod == CompressionMethod.Deflated)
{
base.deflater_.Reset();
base.deflater_.SetLevel(defaultCompressionLevel);
}
this.size = 0L;
if (entry.IsCrypted)
{
if (entry.AESKeySize > 0)
{
this.WriteAESHeader(entry);
}
else if (entry.Crc < 0L)
{
this.WriteEncryptionHeader(entry.DosTime << 0x10);
}
else
{
this.WriteEncryptionHeader(entry.Crc);
}
}
}
2.ZipOutputStream類Finish()：
public override void Finish()
{
if (this.entries != null)
{
if (this.curEntry != null)
{
this.CloseEntry();
}
long count = this.entries.Count;
long sizeEntries = 0L;
foreach (ZipEntry entry in this.entries)
{
this.WriteLeInt(0x2014b50);
this.WriteLeShort(0x33);
this.WriteLeShort(entry.Version);
this.WriteLeShort(entry.Flags);
this.WriteLeShort((short) entry.CompressionMethodForHeader);
this.WriteLeInt((int) entry.DosTime);
this.WriteLeInt((int) entry.Crc);
if (entry.IsZip64Forced() || (entry.CompressedSize >= 0xffffffffL))
{
this.WriteLeInt(-1);
}
else
{
this.WriteLeInt((int) entry.CompressedSize);
}
if (entry.IsZip64Forced() || (entry.Size >= 0xffffffffL))
{
this.WriteLeInt(-1);
}
else
{
this.WriteLeInt((int) entry.Size);
}
byte[] buffer = ZipConstants.ConvertToArray(entry.Flags, entry.Name);
if (buffer.Length > 0xffff)
{
throw new ZipException("Name too long.");
}
ZipExtraData extraData = new ZipExtraData(entry.ExtraData);
if (entry.CentralHeaderRequiresZip64)
{
extraData.StartNewEntry();
if (entry.IsZip64Forced() || (entry.Size >= 0xffffffffL))
{
extraData.AddLeLong(entry.Size);
}
if (entry.IsZip64Forced() || (entry.CompressedSize >= 0xffffffffL))
{
extraData.AddLeLong(entry.CompressedSize);
}
if (entry.Offset >= 0xffffffffL)
{
extraData.AddLeLong(entry.Offset);
}
extraData.AddNewEntry(1);
}
else
{
extraData.Delete(1);
}
if (entry.AESKeySize > 0)
{
AddExtraDataAES(entry, extraData);
}
byte[] entryData = extraData.GetEntryData();
byte[] buffer3 = (entry.Comment != null) ? ZipConstants.ConvertToArray(entry.Flags, entry.Comment) : new byte[0];
if (buffer3.Length > 0xffff)
{
throw new ZipException("Comment too long.");
}
this.WriteLeShort(buffer.Length);
this.WriteLeShort(entryData.Length);
this.WriteLeShort(buffer3.Length);
this.WriteLeShort(0);
this.WriteLeShort(0);
if (entry.ExternalFileAttributes != -1)
{
this.WriteLeInt(entry.ExternalFileAttributes);
}
else if (entry.IsDirectory)
{
this.WriteLeInt(0x10);
}
else
{
this.WriteLeInt(0);
}
if (entry.Offset >= 0xffffffffL)
{
this.WriteLeInt(-1);
}
else
{
this.WriteLeInt((int) entry.Offset);
}
if (buffer.Length > 0)
{
base.baseOutputStream_.Write(buffer, 0, buffer.Length);
}
if (entryData.Length > 0)
{
base.baseOutputStream_.Write(entryData, 0, entryData.Length);
}
if (buffer3.Length > 0)
{
base.baseOutputStream_.Write(buffer3, 0, buffer3.Length);
}
sizeEntries += ((0x2e + buffer.Length) + entryData.Length) + buffer3.Length;
}
using (ZipHelperStream stream = new ZipHelperStream(base.baseOutputStream_))
{
stream.WriteEndOfCentralDirectory(count, sizeEntries, this.offset, this.zipComment);
}
this.entries = null;
}
}
3.ZipEntry類Clone()：
public object Clone()
{
ZipEntry entry = (ZipEntry) base.MemberwiseClone();
if (this.extra != null)
{
entry.extra = new byte[this.extra.Length];
Array.Copy(this.extra, 0, entry.extra, 0, this.extra.Length);
}
return entry;
}
4.ZipOutputStream類Write()：
public override void Write(byte[] buffer, int offset, int count)
{
if (this.curEntry == null)
{
throw new InvalidOperationException("No open entry.");
}
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset", "Cannot be negative");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count", "Cannot be negative");
}
if ((buffer.Length - offset) < count)
{
throw new ArgumentException("Invalid offset/count combination");
}
this.crc.Update(buffer, offset, count);
this.size += count;
switch (this.curMethod)
{
case CompressionMethod.Stored:
if (base.Password != null)
{
this.CopyAndEncrypt(buffer, offset, count);
}
else
{
base.baseOutputStream_.Write(buffer, offset, count);
}
break;
case CompressionMethod.Deflated:
base.Write(buffer, offset, count);
break;
}
}
三.SharpZipLib實例：
1.壓縮單個文件：
/// <summary>
/// 壓縮單個文件
/// </summary>
/// <param name="fileToZip">要壓縮的文件</param>
/// <param name="zipedFile">壓縮後的文件</param>
/// <param name="compressionLevel">壓縮等級</param>
/// <param name="blockSize">每次寫入大小</param>
public static void ZipFile(string fileToZip, string zipedFile, int compressionLevel, int blockSize)
{
if (string.IsNullOrEmpty(fileToZip))
{
throw new ArgumentNullException(fileToZip);
}
if (string.IsNullOrEmpty(zipedFile))
{
throw new ArgumentNullException(zipedFile);
}
if (!File.Exists(fileToZip))
{
throw new FileNotFoundException("指定要壓縮的文件: " + fileToZip + " 不存在!");
}
try
{
using (var zipFile = File.Create(zipedFile))
{
using (var zipStream = new ZipOutputStream(zipFile))
{
using (var streamToZip = new FileStream(fileToZip, FileMode.Open, FileAccess.Read))
{
var fileName = fileToZip.Substring(fileToZip.LastIndexOf("\\", StringComparison.Ordinal) + 1);
var zipEntry = new ZipEntry(fileName);
zipStream.PutNextEntry(zipEntry);
zipStream.SetLevel(compressionLevel);
var buffer = new byte[blockSize];
try
{
int sizeRead;
do
{
sizeRead = streamToZip.Read(buffer, 0, buffer.Length);
zipStream.Write(buffer, 0, sizeRead);
}
while (sizeRead > 0);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
streamToZip.Close();
}
zipStream.Finish();
zipStream.Close();
}
zipFile.Close();
}
}
catch (IOException ioex)
{
throw new IOException(ioex.Message);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
2. 壓縮單個文件：
/// <summary>
/// 壓縮單個文件
/// </summary>
/// <param name="fileToZip">要進行壓縮的文件名</param>
/// <param name="zipedFile">壓縮後生成的壓縮文件名</param>
public static void ZipFile(string fileToZip, string zipedFile)
{
if (string.IsNullOrEmpty(fileToZip))
{
throw new ArgumentException(fileToZip);
}
if (string.IsNullOrEmpty(zipedFile))
{
throw new ArgumentException(zipedFile);
}
if (!File.Exists(fileToZip))
{
throw new FileNotFoundException("指定要壓縮的文件: " + fileToZip + " 不存在!");
}
try
{
using (var fs = File.OpenRead(fileToZip))
{
var buffer = new byte[fs.Length];
fs.Read(buffer, 0, buffer.Length);
fs.Close();
using (var zipFile = File.Create(zipedFile))
{
using (var zipStream = new ZipOutputStream(zipFile))
{
var fileName = fileToZip.Substring(fileToZip.LastIndexOf("\\", StringComparison.Ordinal) + 1);
var zipEntry = new ZipEntry(fileName);
zipStream.PutNextEntry(zipEntry);
zipStream.SetLevel(5);
zipStream.Write(buffer, 0, buffer.Length);
zipStream.Finish();
zipStream.Close();
}
}
}
}
catch (IOException ioex)
{
throw new IOException(ioex.Message);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
3.壓縮多層目錄：
/// <summary>
/// 壓縮多層目錄
/// </summary>
/// <param name="strDirectory">目錄</param>
/// <param name="zipedFile">壓縮文件</param>
public static void ZipFileDirectory(string strDirectory, string zipedFile)
{
if (string.IsNullOrEmpty(strDirectory))
{
throw new ArgumentException(strDirectory);
}
if (string.IsNullOrEmpty(zipedFile))
{
throw new ArgumentException(zipedFile);
}
using (var zipFile = File.Create(zipedFile))
{
using (var s = new ZipOutputStream(zipFile))
{
ZipSetp(strDirectory, s, "");
}
}
}
4.遞歸遍歷目錄：
/// <summary>
/// 遞歸遍歷目錄
/// </summary>
/// <param name="strDirectory">目錄</param>
/// <param name="s">ZipOutputStream對象</param>
/// <param name="parentPath">父路徑</param>
private static void ZipSetp(string strDirectory, ZipOutputStream s, string parentPath)
{
if (strDirectory[strDirectory.Length - 1] != Path.DirectorySeparatorChar)
{
strDirectory += Path.DirectorySeparatorChar;
}
var crc = new Crc32();
var filenames = Directory.GetFileSystemEntries(strDirectory);
try
{
// 遍歷所有的文件和目錄
foreach (var file in filenames)
{
// 先當作目錄處理如果存在這個目錄就遞歸Copy該目錄下面的文件
if (Directory.Exists(file))
{
var pPath = parentPath;
pPath += file.Substring(file.LastIndexOf("\\", StringComparison.Ordinal) + 1);
pPath += "\\";
ZipSetp(file, s, pPath);
}
// 否則直接壓縮文件
else
{
//打開壓縮文件
using (var fs = File.OpenRead(file))
{
var buffer = new byte[fs.Length];
fs.Read(buffer, 0, buffer.Length);
var fileName = parentPath + file.Substring(file.LastIndexOf("\\", StringComparison.Ordinal) + 1);
var entry = new ZipEntry(fileName)
{
DateTime = DateTime.Now,
Size = fs.Length
};
fs.Close();
crc.Reset();
crc.Update(buffer);
entry.Crc = crc.Value;
s.PutNextEntry(entry);
s.Write(buffer, 0, buffer.Length);
}
}
}
}
catch (IOException ioex)
{
throw new IOException(ioex.Message);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
5.解壓縮一個 zip 文件：
/// <summary>
/// 解壓縮一個 zip 文件。
/// </summary>
/// <param name="zipedFile">The ziped file.</param>
/// <param name="strDirectory">The STR directory.</param>
/// <param name="password">zip 文件的密碼。</param>
/// <param name="overWrite">是否覆蓋已存在的文件。</param>
public void UnZip(string zipedFile, string strDirectory, string password, bool overWrite)
{
if (string.IsNullOrEmpty(zipedFile))
{
throw new ArgumentException(zipedFile);
}
if (string.IsNullOrEmpty(strDirectory))
{
throw new ArgumentException(strDirectory);
}
if (string.IsNullOrEmpty(password))
{
throw new ArgumentException(password);
}
if (strDirectory == "")
{
strDirectory = Directory.GetCurrentDirectory();
}
if (!strDirectory.EndsWith("\\"))
{
strDirectory = strDirectory + "\\";
}
try
{
using (var s = new ZipInputStream(File.OpenRead(zipedFile)))
{
s.Password = password;
ZipEntry theEntry;
while ((theEntry = s.GetNextEntry()) != null)
{
var directoryName = string.Empty;
var pathToZip = theEntry.Name;
if (pathToZip != "")
{
directoryName = Path.GetDirectoryName(pathToZip) + "\\";
}
var fileName = Path.GetFileName(pathToZip);
Directory.CreateDirectory(strDirectory + directoryName);
if (fileName == "") continue;
if ((!File.Exists(strDirectory + directoryName + fileName) || !overWrite) &&
(File.Exists(strDirectory + directoryName + fileName))) continue;
using (var streamWriter = File.Create(strDirectory + directoryName + fileName))
{
var data = new byte[2048];
while (true)
{
var size = s.Read(data, 0, data.Length);
if (size > 0)
streamWriter.Write(data, 0, size);
else
break;
}
streamWriter.Close();
}
}
s.Close();
}
}
catch (IOException ioex)
{
throw new IOException(ioex.Message);
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
四.總結：
以上是對SharpZipLib組件的相關介紹，本文的講解上比較的淺顯，如果需要深入的學習可以進入官網進行詳細的學習。組件的功能是很強大的，如何在項目中使用組件，完成我們在項目中需要實現的功能，這就是對每個開發者提出了要求，需要我們仔細的去考慮。
任何學習都需要我們自己去探索和思考，對於一個開發者來說，最重要的就是思考，因為在我們的職業生涯中，沒有什麼的重要性能夠超過思考。如果有不足之處還望各位讀者包含，並留言指正。
