C#文件的分割与合并

标签：c#   文件   分割   合并   

        //--------------------文件，分割与合并---------------------------------------- using System.IO
        /// <summary>
        /// 单个文件分割函数,
        /// 可将任意文件fileIn分割为若干个子文件， 单个子文件最大为 len KB
        /// delet标识文件分割完成后是否删除原文件, change为加密密匙
        /// fileIn = "D:\\file.rar", 子文件名形如"D:\\file.rar@_1.split"
        /// </summary>
        public void fileSplit(String fileIn, int KBlen, bool delet, int change)
        {
            //输入文件校验
            if (fileIn == null || !System.IO.File.Exists(fileIn))
            {
                MessageBox.Show("文件" + fileIn + "不存在！");
                return;
            }

            //加密初始化
            short sign = 1;
            int num = 0, tmp;
            if (change < 0) { sign = -1; change = -change; }

            //取文件名和后缀, fileIn = "D:\\1.rar"

            //从文件创建输入流
            FileStream FileIn = new FileStream(fileIn, FileMode.Open);
            byte[] data = new byte[1024];   //流读取,缓存空间
            int len = 0, I = 1;             //记录子文件累积读取的KB大小, 分割的子文件序号

            FileStream FileOut = null;      //输出流
            int readLen = 0;                //每次实际读取的字节大小
            while (readLen > 0 || (readLen = FileIn.Read(data, 0, data.Length)) > 0) //读取数据
            {
                //创建分割后的子文件，已有则覆盖，子文件"D:\\1.rar@_1.split"
                if (len == 0) FileOut = new FileStream(fileIn + "@_" + I++ + ".split", FileMode.Create);

                //加密逻辑,对data的首字节进行逻辑偏移加密
                if (num == 0) num = change;
                tmp = data[0] + sign * (num % 3 + 3);
                if (tmp > 255) tmp -= 255;
                else if (tmp < 0) tmp += 255;
                data[0] = (byte)tmp;
                num /= 3;

                //输出，缓存数据写入子文件
                FileOut.Write(data, 0, readLen);
                FileOut.Flush();

                //预读下一轮缓存数据
                readLen = FileIn.Read(data, 0, data.Length);
                if (++len >= KBlen || readLen == 0)     //子文件达到指定大小，或文件已读完
                {
                    FileOut.Close();                    //关闭当前输出流
                    len = 0;
                }
            }

            FileIn.Close();                             //关闭输入流
            if (delet) System.IO.File.Delete(fileIn);   //删除源文件
        }

        /// <summary>
        /// 对多个文件进行分割操作
        /// </summary>
        public void fileSplit(String[] fileIn, int KBlen, bool delet, int change)
        {
            if (fileIn == null || fileIn.Length == 0) return;

            for (int i = 0; i < fileIn.Length; i++)
                fileSplit(fileIn[i], KBlen, delet, change);
            MessageBox.Show("文件分割完成！");
        }

        /// <summary>
        /// 文件合并函数,
        /// 可将任意个子文件合并为一个,为fileSplit()的逆过程
        /// delet标识是否删除原文件, change对data的首字节进行解密
        /// </summary>
        public void fileCombine(String[] fileIn, bool delet, int change)
        {
            //输入文件名校验
            if (fileIn == null || fileIn.Length == 0) return;

            //加密初始化
            short sign = 1;
            int num = 0, tmp;
            if (change < 0) { sign = -1; change = -change; }

            //从首个子文件解析原文件名, fileIn[0] = "D:\\1.rar@_1.split"
            
            string name = fileIn[0];
            int i1 = name.LastIndexOf("@_"), i2 = name.LastIndexOf('.');
            name = name.Substring(0, i2);                                   //剔除子文件拓展名".split"
            string fileOut = (i1 == -1) ? name : name.Remove(i1, i2 - i1);  //剔除"@_1" -> "D:\\1.rar.split"                      

            //创建输出文件，已有则覆盖
            FileStream FileOut = new FileStream(fileOut, FileMode.Create);

            for (int i = 0; i < fileIn.Length; i++)
            {
                //输入文件校验
                if (fileIn[i] == null || !System.IO.File.Exists(fileIn[i])) continue;

                //从子文件创建输入流
                FileStream FileIn = new FileStream(fileIn[i], FileMode.Open);
                byte[] data = new byte[1024];   //流读取,缓存空间
                int readLen = 0;                //每次实际读取的字节大小

                while ((readLen = FileIn.Read(data, 0, data.Length)) > 0)       //读取数据
                {
                    //解密逻辑,对data的首字节进行逻辑偏移解密
                    if (num == 0) num = change;
                    tmp = data[0] + sign * (num % 3 + 3);
                    if (tmp > 255) tmp -= 255;
                    else if (tmp < 0) tmp += 255;
                    data[0] = (byte)tmp;
                    num /= 3;

                    //输出，缓存数据写入文件
                    FileOut.Write(data, 0, readLen);
                    FileOut.Flush();
                }

                //关闭输入流，删除源文件
                FileIn.Close();
                if (delet) System.IO.File.Delete(fileIn[i]);
            }

            FileOut.Close();    //关闭输出流
        }

        /// <summary>
        /// 对多组子文件进行合并
        /// </summary>
        public void fileCombine(String[][] fileIn, bool delet, int change)
        {
            for (int i = 0; i < fileIn.Length; i++)
                fileCombine(fileIn[i], delet, change);
            MessageBox.Show("文件合并完成！");
        }

C#文件的分割与合并

标签：c#   文件   分割   合并   

原文地址：http://blog.csdn.net/scimence/article/details/44827813