[壓縮]C#下使用SevenZipSharp壓縮解壓文本

using SevenZip;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SLibrary
{
  public  class SevenZipUtil
    {
        /// <summary>
        /// 壓縮字符串
        /// </summary>
        /// <param name="input">源字符串</param>
        /// <returns>壓縮后字節數組</returns>
        public static byte[] Compress(string input)
        {
            byte[] compressed = null;
            SevenZipCompressor compressor = new SevenZipCompressor();
            compressor.CompressionMethod = CompressionMethod.Ppmd;
            compressor.CompressionLevel = CompressionLevel.High;
            using (MemoryStream msin = GetUTF8MemorySteam(input))
            {
                using (MemoryStream msout = new MemoryStream())
                {
                    compressor.CompressStream(msin, msout);

                    msout.Position = 0;
                    compressed = new byte[msout.Length];
                    msout.Read(compressed, 0, compressed.Length);
                    /*
                    Console.WriteLine("compressed: ");
                    foreach (byte b in compressed)
                    {
                        Console.Write(b);
                        Console.Write(" ");
                    }
                    Console.WriteLine();
                     */
                }
            }
            return compressed;
        }

        /// <summary>
        /// 獲取輸入字符串的UTF8編碼
        /// </summary>
        /// <param name="input">源字符串</param>
        /// <returns>內存數據流</returns>
        private static MemoryStream GetUTF8MemorySteam(string input)
        {
            MemoryStream ms = new MemoryStream();
            byte[] bytes = Encoding.UTF8.GetBytes(input);
            ms.Write(bytes, 0, bytes.Length);
            return ms;
        }

        /// <summary>
        /// 解壓字節數組
        /// </summary>
        /// <param name="input">源字節數組</param>
        /// <returns>解壓后字符串</returns>
        public static string Decompress(byte[] input)
        {
            /*
            Console.WriteLine("input:");
            foreach (byte b in input)
            {
                Console.Write(b);
                Console.Write(" ");
            }
            Console.WriteLine();
            */
            byte[] uncompressedbuffer = null;
            using (MemoryStream msin = new MemoryStream())
            {
                msin.Write(input, 0, input.Length);
                uncompressedbuffer = new byte[input.Length];
                msin.Position = 0;
                using (SevenZipExtractor extractor = new SevenZipExtractor(msin))
                {
                    using (MemoryStream msout = new MemoryStream())
                    {
                        extractor.ExtractFile(0, msout);
                        msout.Position = 0;
                        uncompressedbuffer = new byte[msout.Length];
                        msout.Read(uncompressedbuffer, 0, uncompressedbuffer.Length);
                    }
                }
            }
            return Encoding.UTF8.GetString(uncompressedbuffer);
        }

    }
}