回复 #1 yizidendai 的帖子

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using System;using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace base64_
{
   public partial class Form1 : Form
   {
         public Form1()
         {
            InitializeComponent();
         }
         string base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";//编码后的字符集
         int[] base64DecodeChars = new int[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };//对应ASICC字符的位置
         string base64encode(string str)
         { //加密
            string Out = "";
            int i = 0, len = str.Length;
            char c1, c2, c3;
            while (i < len)
            {
               c1 = Convert.ToChar(str[i++] & 0xff);
               if (i == len)
               {
                     Out += base64EncodeChars[c1 >> 2];
                     Out += base64EncodeChars[(c1 & 0x3) << 4];
                     Out += "==";
                     break;
               }
               c2 = str[i++];
               if (i == len)
               {
                     Out += base64EncodeChars[c1 >> 2];
                     Out += base64EncodeChars[((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)];
                     Out += base64EncodeChars[(c2 & 0xF) << 2];
                     Out += "=";
                     break;
               }
               c3 = str[i++];
               Out += base64EncodeChars[c1 >> 2];
               Out += base64EncodeChars[((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)];
               Out += base64EncodeChars[((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6)];
               Out += base64EncodeChars[c3 & 0x3F];
            }
            return Out;
         }
         string utf16to8(string str)
         {
            string Out = "";
            int i, len;
            char c;//char为16位Unicode字符,范围0~0xffff,感谢vczh提醒
            len = str.Length;
            for (i = 0; i < len; i++)
            {//根据字符的不同范围分别转化
               c = str;
               if ((c >= 0x0001) && (c <= 0x007F))
               {
                     Out += str;
               }
               else if (c > 0x07FF)
               {
                     Out += (char)(0xE0 | ((c >> 12) & 0x0F));
                     Out += (char)(0x80 | ((c >> 6) & 0x3F));
                     Out += (char)(0x80 | ((c >> 0) & 0x3F));
               }
               else
               {
                     Out += (char)(0xC0 | ((c >> 6) & 0x1F));
                     Out += (char)(0x80 | ((c >> 0) & 0x3F));
               }
            }
            return Out;
         }

         string base64decode(string str)
         {//解密
            int c1, c2, c3, c4;
            int i, len;
            string Out;
            len = str.Length;
            i = 0; Out = "";
            while (i < len)
            {
               do
               {
                     c1 = base64DecodeChars[str[i++] & 0xff];
               } while (i < len && c1 == -1);
               if (c1 == -1) break;
               do
               {
                     c2 = base64DecodeChars[str[i++] & 0xff];
               } while (i < len && c2 == -1);
               if (c2 == -1) break;
               Out += (char)((c1 << 2) | ((c2 & 0x30) >> 4));
               do
               {
                     c3 = str[i++] & 0xff;
                     if (c3 == 61) return Out;
                     c3 = base64DecodeChars[c3];
               } while (i < len && c3 == -1);
               if (c3 == -1) break;
               Out += (char)(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
               do
               {
                     c4 = str[i++] & 0xff;
                     if (c4 == 61) return Out;
                     c4 = base64DecodeChars[c4];
               } while (i < len && c4 == -1);
               if (c4 == -1) break;
               Out += (char)(((c3 & 0x03) << 6) | c4);
            }
            return Out;
         }

         string utf8to16(string str)
         {
            string Out = "";
            int i, len;
            char c, char2, char3;
            len = str.Length;
            i = 0; while (i < len)
            {
               c = str[i++];
               switch (c >> 4)
               {
                     case 0:
                     case 1:
                     case 2:
                     case 3:
                     case 4:
                     case 5:
                     case 6:
                     case 7: Out += str[i - 1]; break;
                     case 12:
                     case 13: char2 = str[i++];
                     Out += (char)(((c & 0x1F) << 6) | (char2 & 0x3F)); break;
                     case 14: char2 = str[i++];
                     char3 = str[i++];
                     Out += (char)(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)); break;
               }
            }
            return Out;
         }

         private void button1_Click(object sender, EventArgs e)
         {
            textBox2.Text = base64encode(utf16to8(textBox1.Text));
         }

         private void button2_Click(object sender, EventArgs e)
         {
            textBox1.Text = utf8to16(base64decode(textBox2.Text));
         }

         private void button3_Click(object sender, EventArgs e)
         {
            textBox1.Clear();
            textBox2.Clear();
         }

         private void button4_Click(object sender, EventArgs e)
         {
            Application.Exit();
         }
   }
}