Zip压缩、解压缩方法(GZip)

        /**//// <summary>
        /// 以Zip格式压缩指定文件
        /// </summary>
        /// <param name="源文件">要压缩的文件路径</param>
        /// <param name="目标文件">压缩后保存的文件路径</param>
        public static void 压缩文件(string 源文件, string 目标文件)
        ...{
            if (!File.Exists(源文件)) throw new FileNotFoundException();
            using (FileStream sourceStream = new FileStream(源文件, FileMode.Open, FileAccess.Read, FileShare.Read))
            ...{
                byte[] buffer = new byte[sourceStream.Length];
                int checkCounter = sourceStream.Read(buffer, 0, buffer.Length);
                if (checkCounter != buffer.Length) throw new ApplicationException();
                using (FileStream destinationStream = new FileStream(目标文件, FileMode.OpenOrCreate, FileAccess.Write))
                ...{
                    using (GZipStream compressedStream = new GZipStream(destinationStream, CompressionMode.Compress, true))
                    ...{
                        compressedStream.Write(buffer, 0, buffer.Length);
                    }
                }
            }
        }

        /**//// <summary>
        /// 解压缩指定的Zip文件
        /// </summary>
        /// <param name="源文件">要解压缩的文件路径</param>
        /// <param name="目标文件">解压缩后保存的文件路径</param>
        public static void 解压缩文件(string 源文件, string 目标文件)
        ...{
            if (!File.Exists(源文件)) throw new FileNotFoundException();
            using (FileStream sourceStream = new FileStream(源文件, FileMode.Open))
            ...{
                byte[] quartetBuffer = new byte[4];
                int position = (int)sourceStream.Length - 4;
                sourceStream.Position = position;
                sourceStream.Read(quartetBuffer, 0, 4);
                sourceStream.Position = 0;
                int checkLength = BitConverter.ToInt32(quartetBuffer, 0);
                byte[] buffer = new byte[checkLength + 100];
                using (GZipStream decompressedStream = new GZipStream(sourceStream, CompressionMode.Decompress, true))
                ...{
                    int total = 0;
                    for (int offset = 0; ; )
                    ...{
                        int bytesRead = decompressedStream.Read(buffer, offset, 100);
                        if (bytesRead == 0) break;
                        offset += bytesRead;
                        total += bytesRead;
                    }
                    using (FileStream destinationStream = new FileStream(目标文件, FileMode.Create))
                    ...{
                        destinationStream.Write(buffer, 0, total);
                        destinationStream.Flush();
                    }
                }
            }
        }