C# ZipEntry.ProcessExtraField方法代码示例

//.........这里部分代码省略.........
            zde._commentLength = (short)(block[i++] + block[i++] * 256);
            zde._diskNumber = (UInt32)(block[i++] + block[i++] * 256);

            zde._InternalFileAttrs = (short)(block[i++] + block[i++] * 256);
            zde._ExternalFileAttrs = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;

            zde._RelativeOffsetOfLocalHeader = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);

            // workitem 7801
            zde.IsText = ((zde._InternalFileAttrs & 0x01) == 0x01);

            block = new byte[zde._filenameLength];
            n = s.Read(block, 0, block.Length);
            bytesRead += n;
            if ((zde._BitField & 0x0800) == 0x0800)
            {
                // UTF-8 is in use
                zde._FileNameInArchive = Ionic.Zip.SharedUtilities.Utf8StringFromBuffer(block);
            }
            else
            {
                zde._FileNameInArchive = Ionic.Zip.SharedUtilities.StringFromBuffer(block, expectedEncoding);
            }

            // Console.WriteLine("\nEntry : {0}", zde._LocalFileName);
            // Console.WriteLine("  V Madeby/Needed:      0x{0:X4} / 0x{1:X4}", zde._VersionMadeBy, zde._VersionNeeded);
            // Console.WriteLine("  BitField/Compression: 0x{0:X4} / 0x{1:X4}", zde._BitField, zde._CompressionMethod);
            // Console.WriteLine("  Lastmod:              {0}", zde._LastModified.ToString("u"));
            // Console.WriteLine("  CRC:                  0x{0:X8}", zde._Crc32);
            // Console.WriteLine("  Comp / Uncomp:        0x{0:X8} ({0})   0x{1:X8} ({1})", zde._CompressedSize, zde._UncompressedSize);

            //zde._FileNameInArchive = zde._LocalFileName;

            if (zde.AttributesIndicateDirectory) zde.MarkAsDirectory();  // may append a slash to filename if nec.
            // workitem 6898
            else if (zde._FileNameInArchive.EndsWith("/")) zde.MarkAsDirectory();

            zde._CompressedFileDataSize = zde._CompressedSize;
            if ((zde._BitField & 0x01) == 0x01)
            {
                zde._Encryption_FromZipFile = zde._Encryption = EncryptionAlgorithm.PkzipWeak; // this may change after processing the Extra field
                zde._sourceIsEncrypted = true;
            }

            if (zde._extraFieldLength > 0)
            {
                zde._InputUsesZip64 = (zde._CompressedSize == 0xFFFFFFFF ||
                      zde._UncompressedSize == 0xFFFFFFFF ||
                      zde._RelativeOffsetOfLocalHeader == 0xFFFFFFFF);

                // Console.WriteLine("  Input uses Z64?:      {0}", zde._InputUsesZip64);

                bytesRead += zde.ProcessExtraField(s, zde._extraFieldLength);
                zde._CompressedFileDataSize = zde._CompressedSize;
            }

            // we've processed the extra field, so we know the encryption method is set now.
            if (zde._Encryption == EncryptionAlgorithm.PkzipWeak)
            {
                // the "encryption header" of 12 bytes precedes the file data
                zde._CompressedFileDataSize -= 12;
            }
#if AESCRYPTO
            else if (zde.Encryption == EncryptionAlgorithm.WinZipAes128 ||
                        zde.Encryption == EncryptionAlgorithm.WinZipAes256)
            {
                zde._CompressedFileDataSize = zde.CompressedSize -
                    (ZipEntry.GetLengthOfCryptoHeaderBytes(zde.Encryption) + 10);
                zde._LengthOfTrailer = 10;
            }
#endif

            // tally the trailing descriptor
            if ((zde._BitField & 0x0008) == 0x0008)
            {
                // sig, CRC, Comp and Uncomp sizes
                if (zde._InputUsesZip64)
                    zde._LengthOfTrailer += 24;
                else
                    zde._LengthOfTrailer += 16;
            }

            if (zde._commentLength > 0)
            {
                block = new byte[zde._commentLength];
                n = s.Read(block, 0, block.Length);
                bytesRead += n;
                if ((zde._BitField & 0x0800) == 0x0800)
                {
                    // UTF-8 is in use
                    zde._Comment = Ionic.Zip.SharedUtilities.Utf8StringFromBuffer(block);
                }
                else
                {
                    zde._Comment = Ionic.Zip.SharedUtilities.StringFromBuffer(block, expectedEncoding);
                }
            }
            //zde._LengthOfDirEntry = bytesRead;
            return zde;
        }

        private static bool ReadHeader(ZipEntry ze, System.Text.Encoding defaultEncoding)
        {
            int bytesRead = 0;

            // change for workitem 8098
            ze._RelativeOffsetOfLocalHeader = ze.ArchiveStream.Position;

            int signature = Ionic.Zip.SharedUtilities.ReadEntrySignature(ze.ArchiveStream);
            bytesRead += 4;

            // Return false if this is not a local file header signature.
            if (ZipEntry.IsNotValidSig(signature))
            {
                // Getting "not a ZipEntry signature" is not always wrong or an error.
                // This will happen after the last entry in a zipfile.  In that case, we
                // expect to read :
                //    a ZipDirEntry signature (if a non-empty zip file) or
                //    a ZipConstants.EndOfCentralDirectorySignature.
                //
                // Anything else is a surprise.

                ze.ArchiveStream.Seek(-4, SeekOrigin.Current); // unread the signature
                // workitem 10178
                Ionic.Zip.SharedUtilities.Workaround_Ladybug318918(ze.ArchiveStream);
                if (ZipEntry.IsNotValidZipDirEntrySig(signature) && (signature != ZipConstants.EndOfCentralDirectorySignature))
                {
                    throw new BadReadException(String.Format("  ZipEntry::ReadHeader(): Bad signature (0x{0:X8}) at position  0x{1:X8}", signature, ze.ArchiveStream.Position));
                }
                return false;
            }

            byte[] block = new byte[26];
            int n = ze.ArchiveStream.Read(block, 0, block.Length);
            if (n != block.Length) return false;
            bytesRead += n;

            int i = 0;
            ze._VersionNeeded = (Int16)(block[i++] + block[i++] * 256);
            ze._BitField = (Int16)(block[i++] + block[i++] * 256);
            ze._CompressionMethod_FromZipFile = ze._CompressionMethod = (Int16)(block[i++] + block[i++] * 256);
            ze._TimeBlob = block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256;
            // transform the time data into something usable (a DateTime)
            ze._LastModified = Ionic.Zip.SharedUtilities.PackedToDateTime(ze._TimeBlob);
            ze._timestamp |= ZipEntryTimestamp.DOS;

            if ((ze._BitField & 0x01) == 0x01)
            {
                ze._Encryption_FromZipFile = ze._Encryption = EncryptionAlgorithm.PkzipWeak; // this *may* change after processing the Extra field
                ze._sourceIsEncrypted = true;
            }

            // NB: if ((ze._BitField & 0x0008) != 0x0008), then the Compressed, uncompressed and
            // CRC values are not true values; the true values will follow the entry data.
            // But, regardless of the status of bit 3 in the bitfield, the slots for
            // the three amigos may contain marker values for ZIP64.  So we must read them.
            {
                ze._Crc32 = (Int32)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
                ze._CompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);
                ze._UncompressedSize = (uint)(block[i++] + block[i++] * 256 + block[i++] * 256 * 256 + block[i++] * 256 * 256 * 256);

                if ((uint)ze._CompressedSize == 0xFFFFFFFF ||
                    (uint)ze._UncompressedSize == 0xFFFFFFFF)

                    ze._InputUsesZip64 = true;
            }

            Int16 filenameLength = (short)(block[i++] + block[i++] * 256);
            Int16 extraFieldLength = (short)(block[i++] + block[i++] * 256);

            block = new byte[filenameLength];
            n = ze.ArchiveStream.Read(block, 0, block.Length);
            bytesRead += n;

            // if the UTF8 bit is set for this entry, override the encoding the application requested.
            ze._actualEncoding = ((ze._BitField & 0x0800) == 0x0800)
                ? System.Text.Encoding.UTF8
                : defaultEncoding;

            // need to use this form of GetString() for .NET CF
            ze._FileNameInArchive = ze._actualEncoding.GetString(block, 0, block.Length);

            // when creating an entry by reading, the LocalFileName is the same as the FileNameInArchive
            // No, on second thought, I think it should be empty (null).
            //ze._LocalFileName = ze._FileNameInArchive;

            // workitem 6898
            if (ze._FileNameInArchive.EndsWith("/")) ze.MarkAsDirectory();

            bytesRead += ze.ProcessExtraField(ze.ArchiveStream, extraFieldLength);

            ze._LengthOfTrailer = 0;

            // workitem 6607 - don't read for directories
            // actually get the compressed size and CRC if necessary
            if (!ze._FileNameInArchive.EndsWith("/") && (ze._BitField & 0x0008) == 0x0008)
            {
                // This descriptor exists only if bit 3 of the general
                // purpose bit flag is set (see below).  It is byte aligned
                // and immediately follows the last byte of compressed data,
                // as well as any encryption trailer, as with AES.
//.........这里部分代码省略.........