124 lines
4.6 KiB
C#
124 lines
4.6 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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//字符串编码
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namespace rySafe
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{
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/// <summary>
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/// Base64编码类
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/// </summary>
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public class Base64
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{
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/// <summary>
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/// 编码
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/// </summary>
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/// <param name="Message"></param>
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/// <returns></returns>
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public static string Encode(string Message)
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{
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return Encode(Message, System.Text.Encoding.Default);
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}
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/// <summary>
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/// 把字符串编码成Base64字符串
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/// </summary>
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/// <param name="Message"></param>
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/// <param name="encoding"></param>
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/// <returns></returns>
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public static string Encode(string Message, Encoding encoding)
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{
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char[] Base64Code = new char[]
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{
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
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'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b',
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'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p',
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'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3',
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'4', '5', '6', '7', '8', '9', '+', '/', '='
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};
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byte empty = (byte)0;
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System.Collections.ArrayList byteMessage = new
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System.Collections.ArrayList(encoding.GetBytes
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(Message));
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System.Text.StringBuilder outmessage;
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int messageLen = byteMessage.Count;
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int page = messageLen / 3;
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int use = 0;
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if ((use = messageLen % 3) > 0)
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{
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for (int i = 0; i < 3 - use; i++)
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byteMessage.Add(empty);
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page++;
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}
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outmessage = new System.Text.StringBuilder(page * 4);
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for (int i = 0; i < page; i++)
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{
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byte[] instr = new byte[3];
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instr[0] = (byte)byteMessage[i * 3];
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instr[1] = (byte)byteMessage[i * 3 + 1];
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instr[2] = (byte)byteMessage[i * 3 + 2];
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int[] outstr = new int[4];
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outstr[0] = instr[0] >> 2;
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outstr[1] = ((instr[0] & 0x03) << 4) ^ (instr[1] >> 4);
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if (!instr[1].Equals(empty))
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outstr[2] = ((instr[1] & 0x0f) << 2) ^ (instr[2] >> 6);
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else
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outstr[2] = 64;
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if (!instr[2].Equals(empty))
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outstr[3] = (instr[2] & 0x3f);
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else
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outstr[3] = 64;
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outmessage.Append(Base64Code[outstr[0]]);
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outmessage.Append(Base64Code[outstr[1]]);
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outmessage.Append(Base64Code[outstr[2]]);
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outmessage.Append(Base64Code[outstr[3]]);
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}
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return outmessage.ToString();
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}
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/// <summary>
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/// 解码
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/// </summary>
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/// <param name="Message"></param>
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/// <returns></returns>
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public static string Decode(string Message)
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{
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string Base64Code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
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int page = Message.Length / 4;
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System.Collections.ArrayList outMessage = new System.Collections.ArrayList(page * 3);
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char[] message = Message.ToCharArray();
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for (int i = 0; i < page; i++)
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{
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byte[] instr = new byte[4];
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instr[0] = (byte)Base64Code.IndexOf(message[i * 4]);
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instr[1] = (byte)Base64Code.IndexOf(message[i * 4 + 1]);
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instr[2] = (byte)Base64Code.IndexOf(message[i * 4 + 2]);
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instr[3] = (byte)Base64Code.IndexOf(message[i * 4 + 3]);
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byte[] outstr = new byte[3];
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outstr[0] = (byte)((instr[0] << 2) ^ ((instr[1] & 0x30) >> 4));
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if (instr[2] != 64)
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{
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outstr[1] = (byte)((instr[1] << 4) ^ ((instr[2] & 0x3c) >> 2));
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}
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else
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{
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outstr[2] = 0;
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}
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if (instr[3] != 64)
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{
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outstr[2] = (byte)((instr[2] << 6) ^ instr[3]);
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}
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else
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{
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outstr[2] = 0;
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}
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outMessage.Add(outstr[0]);
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if (outstr[1] != 0)
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outMessage.Add(outstr[1]);
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if (outstr[2] != 0)
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outMessage.Add(outstr[2]);
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}
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byte[] outbyte = (byte[])outMessage.ToArray(Type.GetType("System.Byte"));
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return System.Text.Encoding.Default.GetString(outbyte);
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}
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}
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}
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