ICSharpCode.SharpZipLib.Zip.ZipInputStream.InitialRead C# (CSharp) Method

        int InitialRead(byte[] destination, int offset, int count)
        {
            if (!CanDecompressEntry) {
                throw new ZipException("Library cannot extract this entry. Version required is (" + entry.Version + ")");
            }

            // Handle encryption if required.
            if (entry.IsCrypted) {
                if (password == null) {
                    throw new ZipException("No password set.");
                }

                // Generate and set crypto transform...
                var managed = new PkzipClassicManaged();
                byte[] key = PkzipClassic.GenerateKeys(ZipConstants.ConvertToArray(password));

                inputBuffer.CryptoTransform = managed.CreateDecryptor(key, null);

                byte[] cryptbuffer = new byte[ZipConstants.CryptoHeaderSize];
                inputBuffer.ReadClearTextBuffer(cryptbuffer, 0, ZipConstants.CryptoHeaderSize);

                if (cryptbuffer[ZipConstants.CryptoHeaderSize - 1] != entry.CryptoCheckValue) {
                    throw new ZipException("Invalid password");
                }

                if (csize >= ZipConstants.CryptoHeaderSize) {
                    csize -= ZipConstants.CryptoHeaderSize;
                } else if ((entry.Flags & (int)GeneralBitFlags.Descriptor) == 0) {
                    throw new ZipException(string.Format("Entry compressed size {0} too small for encryption", csize));
                }
            } else {
                inputBuffer.CryptoTransform = null;
            }

            if ((csize > 0) || ((flags & (int)GeneralBitFlags.Descriptor) != 0)) {
                if ((method == (int)CompressionMethod.Deflated) && (inputBuffer.Available > 0)) {
                    inputBuffer.SetInflaterInput(inf);
                }

                internalReader = new ReadDataHandler(BodyRead);
                return BodyRead(destination, offset, count);
            } else {
                internalReader = new ReadDataHandler(ReadingNotAvailable);
                return 0;
            }
        }