C# ZipEntry.IsCompressionMethodSupported方法代码示例

		void ExtractEntry(ZipEntry entry)
		{
			bool doExtraction = entry.IsCompressionMethodSupported();
			string targetName = entry.Name;
			
			if ( doExtraction ) {
				if ( entry.IsFile ) {
					targetName = extractNameTransform_.TransformFile(targetName);
				}
				else if ( entry.IsDirectory ) {
					targetName = extractNameTransform_.TransformDirectory(targetName);
				}
				
				doExtraction = !((targetName == null) || (targetName.Length == 0));
			}
			
			// TODO: Fire delegate/throw exception were compression method not supported, or name is invalid?

			string dirName = null;
			
			if ( doExtraction ) {
					if ( entry.IsDirectory ) {
						dirName = targetName;
					}
					else {
						dirName = Path.GetDirectoryName(Path.GetFullPath(targetName));
					}
			}
			
			if ( doExtraction && !Directory.Exists(dirName) ) {
				if ( !entry.IsDirectory || CreateEmptyDirectories ) {
					try {
						Directory.CreateDirectory(dirName);
					}
					catch (Exception ex) {
						doExtraction = false;
						if ( events_ != null ) {
							if ( entry.IsDirectory ) {
								continueRunning_ = events_.OnDirectoryFailure(targetName, ex);
							}
							else {
								continueRunning_ = events_.OnFileFailure(targetName, ex);
							}
						}
						else {
							continueRunning_ = false;
                            throw;
						}
					}
				}
			}
			
			if ( doExtraction && entry.IsFile ) {
				ExtractFileEntry(entry, targetName);
			}
		}

		/// <summary>
		/// Test a local header against that provided from the central directory
		/// </summary>
		/// <param name="entry">
		/// The entry to test against
		/// </param>
		/// <param name="tests">The type of <see cref="HeaderTest">tests</see> to carry out.</param>
		/// <returns>The offset of the entries data in the file</returns>
		long TestLocalHeader(ZipEntry entry, HeaderTest tests)
		{
			lock(baseStream_) 
			{
				bool testHeader = (tests & HeaderTest.Header) != 0;
				bool testData = (tests & HeaderTest.Extract) != 0;

				baseStream_.Seek(offsetOfFirstEntry + entry.Offset, SeekOrigin.Begin);
				if ((int)ReadLEUint() != ZipConstants.LocalHeaderSignature) {
					throw new ZipException(string.Format("Wrong local header signature @{0:X}", offsetOfFirstEntry + entry.Offset));
				}

				short extractVersion = ( short )ReadLEUshort();
				short localFlags = ( short )ReadLEUshort();
				short compressionMethod = ( short )ReadLEUshort();
				short fileTime = ( short )ReadLEUshort();
				short fileDate = ( short )ReadLEUshort();
				uint crcValue = ReadLEUint();
				long compressedSize = ReadLEUint();
				long size = ReadLEUint();
				int storedNameLength = ReadLEUshort();
				int extraDataLength = ReadLEUshort();

				byte[] nameData = new byte[storedNameLength];
				StreamUtils.ReadFully(baseStream_, nameData);

				byte[] extraData = new byte[extraDataLength];
				StreamUtils.ReadFully(baseStream_, extraData);

				ZipExtraData localExtraData = new ZipExtraData(extraData);

				// Extra data / zip64 checks
				if (localExtraData.Find(1))
				{
					// 2010-03-04 Forum 10512: removed checks for version >= ZipConstants.VersionZip64
					// and size or compressedSize = MaxValue, due to rogue creators.

					size = localExtraData.ReadLong();
					compressedSize = localExtraData.ReadLong();

                    if ((localFlags & (int)GeneralBitFlags.Descriptor) != 0)
                    {
                        // These may be valid if patched later
                        if ( (size != -1) && (size != entry.Size)) {
                            throw new ZipException("Size invalid for descriptor");
                        }

                        if ((compressedSize != -1) && (compressedSize != entry.CompressedSize)) {
                            throw new ZipException("Compressed size invalid for descriptor");
                        }
                    }
                }
				else
				{
					// No zip64 extra data but entry requires it.
					if ((extractVersion >= ZipConstants.VersionZip64) &&
						(((uint)size == uint.MaxValue) || ((uint)compressedSize == uint.MaxValue)))
					{
						throw new ZipException("Required Zip64 extended information missing");
					}
				}

				if ( testData ) {
					if ( entry.IsFile ) {
						if ( !entry.IsCompressionMethodSupported() ) {
							throw new ZipException("Compression method not supported");
						}

						if ( (extractVersion > ZipConstants.VersionMadeBy)
							|| ((extractVersion > 20) && (extractVersion < ZipConstants.VersionZip64)) ) {
							throw new ZipException(string.Format("Version required to extract this entry not supported ({0})", extractVersion));
						}

						if ( (localFlags & ( int )(GeneralBitFlags.Patched | GeneralBitFlags.StrongEncryption | GeneralBitFlags.EnhancedCompress | GeneralBitFlags.HeaderMasked)) != 0 ) {
							throw new ZipException("The library does not support the zip version required to extract this entry");
						}
					}
				}

                if (testHeader)
                {
                    if ((extractVersion <= 63) &&	// Ignore later versions as we dont know about them..
                        (extractVersion != 10) &&
                        (extractVersion != 11) &&
                        (extractVersion != 20) &&
                        (extractVersion != 21) &&
                        (extractVersion != 25) &&
                        (extractVersion != 27) &&
                        (extractVersion != 45) &&
                        (extractVersion != 46) &&
                        (extractVersion != 50) &&
                        (extractVersion != 51) &&
//.........这里部分代码省略.........

        void ExtractEntry(ZipEntry entry)
        {
            bool doExtraction = false;
			
            string nameText = entry.Name;
			
            if ( entry.IsFile ) {
                // TODO: Translate invalid names allowing extraction still.
                doExtraction = NameIsValid(nameText) && entry.IsCompressionMethodSupported();
            }
            else if ( entry.IsDirectory ) {
                doExtraction = NameIsValid(nameText);
            }
			
            // TODO: Fire delegate were compression method not supported, or name is invalid?

            string dirName = null;
            string targetName = null;
			
            if ( doExtraction ) {
                // Handle invalid entry names by chopping of path root.
                if (Path.IsPathRooted(nameText)) {
                    string workName = Path.GetPathRoot(nameText);
                    nameText = nameText.Substring(workName.Length);
                }
				
                if ( nameText.Length > 0 )
                {
                    targetName = Path.Combine(targetDirectory_, nameText);
                    dirName = entry.IsDirectory ? targetName : Path.GetDirectoryName(Path.GetFullPath(targetName));
                }
                else {
                    doExtraction = false;
                }
            }
			
            if ( doExtraction && !Directory.Exists(dirName) ) {
                if ( !entry.IsDirectory || CreateEmptyDirectories ) {
                    try {
                        Directory.CreateDirectory(dirName);
                    }
                    catch (Exception ex) {
                        doExtraction = false;
                        if ( events_ != null ) {
                            continueRunning_ = entry.IsDirectory ? events_.OnDirectoryFailure(targetName, ex) : events_.OnFileFailure(targetName, ex);
                        }
                        else {
                            continueRunning_ = false;
                        }
                    }
                }
            }
			
            if ( doExtraction && entry.IsFile ) {
                ExtractFileEntry(entry, targetName);
            }
        }

//.........这里部分代码省略.........
				header == ZipConstants.ArchiveExtraDataSignature ||
				header == ZipConstants.Zip64CentralFileHeaderSignature) {
				// No more individual entries exist
				Close();
				return null;
			}
			
			// -jr- 07-Dec-2003 Ignore spanning temporary signatures if found
			// Spanning signature is same as descriptor signature and is untested as yet.
			if ( (header == ZipConstants.SpanningTempSignature) || (header == ZipConstants.SpanningSignature) ) {
				header = inputBuffer.ReadLeInt();
			}
			
			if (header != ZipConstants.LocalHeaderSignature) {
				throw new ZipException("Wrong Local header signature: 0x" + String.Format("{0:X}", header));
			}
			
			short versionRequiredToExtract = (short)inputBuffer.ReadLeShort();
			
			flags          = inputBuffer.ReadLeShort();
			method         = inputBuffer.ReadLeShort();
			uint dostime   = (uint)inputBuffer.ReadLeInt();
			int crc2       = inputBuffer.ReadLeInt();
			csize          = inputBuffer.ReadLeInt();
			size           = inputBuffer.ReadLeInt();
			int nameLen    = inputBuffer.ReadLeShort();
			int extraLen   = inputBuffer.ReadLeShort();
			
			bool isCrypted = (flags & 1) == 1;
			
			byte[] buffer = new byte[nameLen];
			inputBuffer.ReadRawBuffer(buffer);
			
			string name = ZipConstants.ConvertToStringExt(flags, buffer);
			
			entry = new ZipEntry(name, versionRequiredToExtract);
			entry.Flags = flags;
			
			entry.CompressionMethod = (CompressionMethod)method;
			
			if ((flags & 8) == 0) {
				entry.Crc  = crc2 & 0xFFFFFFFFL;
				entry.Size = size & 0xFFFFFFFFL;
				entry.CompressedSize = csize & 0xFFFFFFFFL;

				entry.CryptoCheckValue = (byte)((crc2 >> 24) & 0xff);

			} else {
				
				// This allows for GNU, WinZip and possibly other archives, the PKZIP spec
				// says these values are zero under these circumstances.
				if (crc2 != 0) {
					entry.Crc = crc2 & 0xFFFFFFFFL;
				}
				
				if (size != 0) {
					entry.Size = size & 0xFFFFFFFFL;
				}

				if (csize != 0) {
					entry.CompressedSize = csize & 0xFFFFFFFFL;
				}

				entry.CryptoCheckValue = (byte)((dostime >> 8) & 0xff);
			}
			
			entry.DosTime = dostime;

			// If local header requires Zip64 is true then the extended header should contain
			// both values.

			// Handle extra data if present.  This can set/alter some fields of the entry.
			if (extraLen > 0) {
				byte[] extra = new byte[extraLen];
				inputBuffer.ReadRawBuffer(extra);
				entry.ExtraData = extra;
			}

			entry.ProcessExtraData(true);
			if ( entry.CompressedSize >= 0 ) {
				csize = entry.CompressedSize;
			}

			if ( entry.Size >= 0 ) {
				size = entry.Size;
			}
			
			if (method == (int)CompressionMethod.Stored && (!isCrypted && csize != size || (isCrypted && csize - ZipConstants.CryptoHeaderSize != size))) {
				throw new ZipException("Stored, but compressed != uncompressed");
			}

			// Determine how to handle reading of data if this is attempted.
			if (entry.IsCompressionMethodSupported()) {
				internalReader = new ReadDataHandler(InitialRead);
			} else {
				internalReader = new ReadDataHandler(ReadingNotSupported);
			}
			
			return entry;
		}