前面介绍了六种.NET组件,其中有一种组件是写文件的压缩和解压,现在介绍另一种文件的解压缩组件SharpZipLib。在这个组件介绍系列中,只为简单的介绍组件的背景和简单的应用,读者在阅读时可以结合官网的相关介绍和在本地实际操作。
相关的组件功能非常强大,在笔者的介绍中只是提及到简单的应用,需要了解更多的操作和特性,可以根据官网介绍,或者查看DLL文件的相关类和方法,以此来扩展相关的业务需要。
SharpZipLib是一个完全在C#中为.NET平台编写的Zip,GZip,Tar和BZip2库。
一.SharpZipLib组件概述:
ziplib(SharpZipLib,以前的NZipLib)是一个完全在C#为.NET平台编写的Zip,GZip,Tar和BZip2库。它实现为一个程序集(可安装在GAC中),因此可以轻松地集成到其他项目(任何.NET语言)中。 #ziplib的创建者这样说:“我已经将zip库移植到C#,因为我需要gzip / zip压缩,我不想使用libzip.dll或类似的东西我想要的所有在纯C#“。
SharpZipLib官网提供的下载操作:.NET 1.1,.NET 2.0(3.5,4.0),.NET CF 1.0,.NET CF 2.0的装配:下载237 KB,源代码和示例下载708 KB;源代码和示例下载708 KB;帮助文件下载1208 KB;
SharpZipLib是在GPL下发布,遵守开源协议。
二.SharpZipLib核心类和方法介绍:
以上简单的介绍了SharpZipLib组件的相关背景,现在具体看一下该组件的相关核心类和方法:
1.ZipOutputStream类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类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类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类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实例:
1.压缩单个文件:
///2. 压缩单个文件:
///3.压缩多层目录:
///4.递归遍历目录:
///5.解压缩一个 zip 文件:
///四.总结:
以上是对SharpZipLib组件的相关介绍,本文的讲解上比较的浅显,如果需要深入的学习可以进入官网进行详细的学习。组件的功能是很强大的,如何在项目中使用组件,完成我们在项目中需要实现的功能,这就是对每个开发者提出了要求,需要我们仔细的去考虑。
任何学习都需要我们自己去探索和思考,对于一个开发者来说,最重要的就是思考,因为在我们的职业生涯中,没有什么的重要性能够超过思考。如果有不足之处还望各位读者包含,并留言指正。
你看看http://blog.csdn.net/wjverson/article/details/6226160这里的解压文件是如何含路径的。