zipfile.cs

Microsoft Mobile Development Handbook的代码,有C#,VB,C++的

		
		/// <summary>
		/// Returns an enumerator for the Zip entries in this Zip file.
		/// </summary>
		/// <exception cref="InvalidOperationException">
		/// The Zip file has been closed.
		/// </exception>
		public IEnumerator GetEnumerator()
		{
			if (entries == null) {
				throw new InvalidOperationException("ZipFile has closed");
			}
			
			return new ZipEntryEnumeration(entries);
		}
		
		/// <summary>
		/// Return the index of the entry with a matching name
		/// </summary>
		/// <param name="name">Entry name to find</param>
		/// <param name="ignoreCase">If true the comparison is case insensitive</param>
		/// <returns>The index position of the matching entry or -1 if not found</returns>
		/// <exception cref="InvalidOperationException">
		/// The Zip file has been closed.
		/// </exception>
		public int FindEntry(string name, bool ignoreCase)
		{
			if (entries == null) {
				throw new InvalidOperationException("ZipFile has been closed");
			}
			
			for (int i = 0; i < entries.Length; i++) {
				if (string.Compare(name, entries[i].Name, ignoreCase) == 0) {
					return i;
				}
			}
			return -1;
		}
		
		/// <summary>
		/// Indexer property for ZipEntries
		/// </summary>
		[System.Runtime.CompilerServices.IndexerNameAttribute("EntryByIndex")]
		public ZipEntry this[int index] {
			get {
				return (ZipEntry) entries[index].Clone();	
			}
		}
		
		/// <summary>
		/// Searches for a zip entry in this archive with the given name.
		/// String comparisons are case insensitive
		/// </summary>
		/// <param name="name">
		/// The name to find. May contain directory components separated by slashes ('/').
		/// </param>
		/// <returns>
		/// The zip entry, or null if no entry with that name exists.
		/// </returns>
		/// <exception cref="InvalidOperationException">
		/// The Zip file has been closed.
		/// </exception>
		public ZipEntry GetEntry(string name)
		{
			if (entries == null) {
				throw new InvalidOperationException("ZipFile has been closed");
			}
			
			int index = FindEntry(name, true);
			return index >= 0 ? (ZipEntry) entries[index].Clone() : null;
		}
		
		/// <summary>
		/// Checks, if the local header of the entry at index i matches the
		/// central directory, and returns the offset to the data.
		/// </summary>
		/// <returns>
		/// The start offset of the (compressed) data.
		/// </returns>
		/// <exception cref="System.IO.EndOfStreamException">
		/// The stream ends prematurely
		/// </exception>
		/// <exception cref="ICSharpCode.SharpZipLib.Zip.ZipException">
		/// The local header signature is invalid, the entry and central header file name lengths are different
		/// or the local and entry compression methods dont match
		/// </exception>
		long CheckLocalHeader(ZipEntry entry)
		{
			lock(baseStream) {
				baseStream.Seek(entry.Offset, SeekOrigin.Begin);
				if (ReadLeInt() != ZipConstants.LOCSIG) {
					throw new ZipException("Wrong Local header signature");
				}
				
				short shortValue = (short)ReadLeShort();     // version required to extract
				if (shortValue > ZipConstants.VERSION_MADE_BY) {
					throw new ZipException(string.Format("Version required to extract this entry not supported ({0})", shortValue));
				}
				
				shortValue = (short)ReadLeShort();                  // general purpose bit flags.
				if ((shortValue & 0x30) != 0) {
					throw new ZipException("The library doesnt support the zip version required to extract this entry");
				}
				
				if (entry.CompressionMethod != (CompressionMethod)ReadLeShort()) {
					throw new ZipException("Compression method mismatch");
				}
				
				// Skip time, crc, size and csize
				long oldPos = baseStream.Position;
				baseStream.Position += ZipConstants.LOCNAM - ZipConstants.LOCTIM;
				
				if (baseStream.Position - oldPos != ZipConstants.LOCNAM - ZipConstants.LOCTIM) {
					throw new ZipException("End of stream");
				}
				
				// TODO make test more correct...  cant compare lengths as was done originally as this can fail for MBCS strings
				int storedNameLength = ReadLeShort();
				if (entry.Name.Length > storedNameLength) {
					throw new ZipException("file name length mismatch");
				}
				
				int extraLen = storedNameLength + ReadLeShort();
				return entry.Offset + ZipConstants.LOCHDR + extraLen;
			}
		}
		
		/// <summary>
		/// Creates an input stream reading the given zip entry as
		/// uncompressed data.  Normally zip entry should be an entry
		/// returned by GetEntry().
		/// </summary>
		/// <returns>
		/// the input stream.
		/// </returns>
		/// <exception cref="InvalidOperationException">
		/// The ZipFile has already been closed
		/// </exception>
		/// <exception cref="ICSharpCode.SharpZipLib.Zip.ZipException">
		/// The compression method for the entry is unknown
		/// </exception>
		/// <exception cref="IndexOutOfRangeException">
		/// The entry is not found in the ZipFile
		/// </exception>
		public Stream GetInputStream(ZipEntry entry)
		{
			if (entries == null) {
				throw new InvalidOperationException("ZipFile has closed");
			}
			
			int index = entry.ZipFileIndex;
			if (index < 0 || index >= entries.Length || entries[index].Name != entry.Name) {
				index = FindEntry(entry.Name, true);
				if (index < 0) {
					throw new IndexOutOfRangeException();
				}
			}
			return GetInputStream(index);			
		}
		

		/// <summary>
		/// Creates an input stream reading the zip entry based on the index passed
		/// </summary>
		/// <returns>
		/// An input stream.
		/// </returns>
		/// <exception cref="InvalidOperationException">
		/// The ZipFile has already been closed
		/// </exception>
		/// <exception cref="ICSharpCode.SharpZipLib.Zip.ZipException">
		/// The compression method for the entry is unknown
		/// </exception>
		/// <exception cref="IndexOutOfRangeException">
		/// The entry is not found in the ZipFile
		/// </exception>
		public Stream GetInputStream(int entryIndex)
		{
			if (entries == null) {
				throw new InvalidOperationException("ZipFile has closed");
			}
			
			long start = CheckLocalHeader(entries[entryIndex]);
			CompressionMethod method = entries[entryIndex].CompressionMethod;
			Stream istr = new PartialInputStream(baseStream, start, entries[entryIndex].CompressedSize);
			
			switch (method) {
				case CompressionMethod.Stored:
					return istr;
				case CompressionMethod.Deflated:
					return new InflaterInputStream(istr, new Inflater(true));
				default:
					throw new ZipException("Unknown compression method " + method);
			}
		}
		
		/// <summary>
		/// Gets the comment for the zip file.
		/// </summary>
		public string ZipFileComment {
			get {
				return comment;
			}
		}
		
		/// <summary>
		/// Gets the name of this zip file.
		/// </summary>
		public string Name {
			get {
				return name;
			}
		}
		
		/// <summary>
		/// Gets the number of entries in this zip file.
		/// </summary>
		/// <exception cref="InvalidOperationException">
		/// The Zip file has been closed.
		/// </exception>
		public int Size {
			get {
				if (entries != null) {
					return entries.Length;
				} else {
					throw new InvalidOperationException("ZipFile is closed");
				}
			}
		}
		
		class ZipEntryEnumeration : IEnumerator
		{
			ZipEntry[] array;
			int ptr = -1;
			
			public ZipEntryEnumeration(ZipEntry[] arr)
			{
				array = arr;
			}
			
			public object Current {
				get {
					return array[ptr];
				}
			}
			
			public void Reset()
			{
				ptr = -1;
			}
			
			public bool MoveNext() 
			{
				return (++ptr < array.Length);
			}
		}
		
		class PartialInputStream : InflaterInputStream
		{
			Stream baseStream;
			long filepos, end;
			
			public PartialInputStream(Stream baseStream, long start, long len) : base(baseStream)
			{
				this.baseStream = baseStream;
				filepos = start;
				end = start + len;
			}
			
			public override int Available 
			{
				get {
					long amount = end - filepos;
					if (amount > Int32.MaxValue) {
						return Int32.MaxValue;
					}
					
					return (int) amount;
				}
			}
			
			public override int ReadByte()
			{
				if (filepos == end) {
					return -1; //ok
				}
				
				lock(baseStream) {
					baseStream.Seek(filepos++, SeekOrigin.Begin);
					return baseStream.ReadByte();
				}
			}
			

			/// <summary>
			/// Close this partial input stream.
			/// </summary>
			/// <remarks>
			/// The underlying stream is not closed.  Close the parent ZipFile class to do that.
			/// </remarks>
			public override void Close()
			{
				// Do nothing at all!
			}
			
			public override int Read(byte[] b, int off, int len)
			{
				if (len > end - filepos) {
					len = (int) (end - filepos);
					if (len == 0) {
						return 0;
					}
				}
				lock(baseStream) {
					baseStream.Seek(filepos, SeekOrigin.Begin);
					int count = baseStream.Read(b, off, len);
					if (count > 0) {
						filepos += len;
					}
					return count;
				}
			}
			
			public long SkipBytes(long amount)
			{
				if (amount < 0) {
					throw new ArgumentOutOfRangeException();
				}
				if (amount > end - filepos) {
					amount = end - filepos;
				}
				filepos += amount;
				return amount;
			}
		}
	}
}