Пример #1
0
        /// <summary>
        /// Advances to the next entry in the archive
        /// </summary>
        /// <returns>
        /// The next <see cref="ZipEntry">entry</see> in the archive or null if there are no more entries.
        /// </returns>
        /// <remarks>
        /// If the previous entry is still open <see cref="CloseEntry">CloseEntry</see> is called.
        /// </remarks>
        /// <exception cref="InvalidOperationException">
        /// Input stream is closed
        /// </exception>
        /// <exception cref="ZipException">
        /// Password is not set, password is invalid, compression method is invalid,
        /// version required to extract is not supported
        /// </exception>
        public ZipEntry GetNextEntry()
        {
            if (crc == null)
            {
                throw new InvalidOperationException("Closed.");
            }

            if (entry != null)
            {
                CloseEntry();
            }

            int header = inputBuffer.ReadLeInt();

            if (header == ZipConstants.CentralHeaderSignature ||
                header == ZipConstants.EndOfCentralDirectorySignature ||
                header == ZipConstants.CentralHeaderDigitalSignature ||
                header == ZipConstants.ArchiveExtraDataSignature ||
                header == ZipConstants.Zip64CentralFileHeaderSignature)
            {
                // No more individual entries exist
                Dispose();
                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));
            }

            var versionRequiredToExtract = (short)inputBuffer.ReadLeShort();

            flags  = inputBuffer.ReadLeShort();
            method = inputBuffer.ReadLeShort();
            var 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);
        }