C# ZipFile.OnReadStarted方法代码示例

        // build the TOC by reading each entry in the file.
        private static void ReadIntoInstance_Orig(ZipFile zf)
        {
            zf.OnReadStarted();
            //zf._entries = new System.Collections.Generic.List<ZipEntry>();
            zf._entries = new System.Collections.Generic.Dictionary<String,ZipEntry>();

            ZipEntry e;
            if (zf.Verbose)
                if (zf.Name == null)
                    zf.StatusMessageTextWriter.WriteLine("Reading zip from stream...");
                else
                    zf.StatusMessageTextWriter.WriteLine("Reading zip {0}...", zf.Name);

            // work item 6647:  PK00 (packed to removable disk)
            bool firstEntry = true;
            ZipContainer zc = new ZipContainer(zf);
            while ((e = ZipEntry.ReadEntry(zc, firstEntry)) != null)
            {
                if (zf.Verbose)
                    zf.StatusMessageTextWriter.WriteLine("  {0}", e.FileName);

                zf._entries.Add(e.FileName,e);
                firstEntry = false;
            }

            // read the zipfile's central directory structure here.
            // workitem 9912
            // But, because it may be corrupted, ignore errors.
            try
            {
                ZipEntry de;
                // in lieu of hashset, use a dictionary
                var previouslySeen = new Dictionary<String,Object>();
                while ((de = ZipEntry.ReadDirEntry(zf, previouslySeen)) != null)
                {
                    // Housekeeping: Since ZipFile exposes ZipEntry elements in the enumerator,
                    // we need to copy the comment that we grab from the ZipDirEntry
                    // into the ZipEntry, so the application can access the comment.
                    // Also since ZipEntry is used to Write zip files, we need to copy the
                    // file attributes to the ZipEntry as appropriate.
                    ZipEntry e1 = zf._entries[de.FileName];
                    if (e1 != null)
                    {
                        e1._Comment = de.Comment;
                        if (de.IsDirectory) e1.MarkAsDirectory();
                    }
                    previouslySeen.Add(de.FileName,null); // to prevent dupes
                }

                // workitem 8299
                if (zf._locEndOfCDS > 0)
                    zf.ReadStream.Seek(zf._locEndOfCDS, SeekOrigin.Begin);

                ReadCentralDirectoryFooter(zf);

                if (zf.Verbose && !String.IsNullOrEmpty(zf.Comment))
                    zf.StatusMessageTextWriter.WriteLine("Zip file Comment: {0}", zf.Comment);
            }
            catch (ZipException) { }
            catch (IOException) { }

            zf.OnReadCompleted();
        }

        private static void ReadIntoInstance(ZipFile zf)
        {
            Stream s = zf.ReadStream;
            try
            {
                zf._readName = zf._name; // workitem 13915
                if (!s.CanSeek)
                {
                    ReadIntoInstance_Orig(zf);
                    return;
                }

                zf.OnReadStarted();

                // change for workitem 8098
                //zf._originPosition = s.Position;

                // Try reading the central directory, rather than scanning the file.

                uint datum = ReadFirstFourBytes(s);

                if (datum == ZipConstants.EndOfCentralDirectorySignature)
                    return;


                // start at the end of the file...
                // seek backwards a bit, then look for the EoCD signature.
                int nTries = 0;
                bool success = false;

                // The size of the end-of-central-directory-footer plus 2 bytes is 18.
                // This implies an archive comment length of 0.  We'll add a margin of
                // safety and start "in front" of that, when looking for the
                // EndOfCentralDirectorySignature
                long posn = s.Length - 64;
                long maxSeekback = Math.Max(s.Length - 0x4000, 10);
                do
                {
                    if (posn < 0) posn = 0;  // BOF
                    s.Seek(posn, SeekOrigin.Begin);
                    long bytesRead = SharedUtilities.FindSignature(s, (int)ZipConstants.EndOfCentralDirectorySignature);
                    if (bytesRead != -1)
                        success = true;
                    else
                    {
                        if (posn==0) break; // started at the BOF and found nothing
                        nTries++;
                        // Weird: with NETCF, negative offsets from SeekOrigin.End DO
                        // NOT WORK. So rather than seek a negative offset, we seek
                        // from SeekOrigin.Begin using a smaller number.
                        posn -= (32 * (nTries + 1) * nTries);
                    }
                }
                while (!success && posn > maxSeekback);

                if (success)
                {
                    // workitem 8299
                    zf._locEndOfCDS = s.Position - 4;

                    byte[] block = new byte[16];
                    s.Read(block, 0, block.Length);

                    zf._diskNumberWithCd = BitConverter.ToUInt16(block, 2);

                    if (zf._diskNumberWithCd == 0xFFFF)
                        throw new ZipException("Spanned archives with more than 65534 segments are not supported at this time.");

                    zf._diskNumberWithCd++; // I think the number in the file differs from reality by 1

                    int i = 12;

                    uint offset32 = (uint) BitConverter.ToUInt32(block, i);
                    if (offset32 == 0xFFFFFFFF)
                    {
                        Zip64SeekToCentralDirectory(zf);
                    }
                    else
                    {
                        zf._OffsetOfCentralDirectory = offset32;
                        // change for workitem 8098
                        s.Seek(offset32, SeekOrigin.Begin);
                    }

                    ReadCentralDirectory(zf);
                }
                else
                {
                    // Could not find the central directory.
                    // Fallback to the old method.
                    // workitem 8098: ok
                    //s.Seek(zf._originPosition, SeekOrigin.Begin);
                    s.Seek(0L, SeekOrigin.Begin);
                    ReadIntoInstance_Orig(zf);
                }
            }
            catch (Exception ex1)
            {
                if (zf._ReadStreamIsOurs && zf._readstream != null)
                {
//.........这里部分代码省略.........