Base64.cs
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上传日期:2019-05-16
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- /*
- Copyright (c) 2005 Poderosa Project, All Rights Reserved.
- This file is a part of the Granados SSH Client Library that is subject to
- the license included in the distributed package.
- You may not use this file except in compliance with the license.
- $Id: Base64.cs,v 1.2 2005/04/20 08:58:56 okajima Exp $
- */
- using System;
- namespace Granados.Toolkit {
- public class Base64 {
- private static readonly int[] _fromBase64 = 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
- };
- private static readonly byte[] _toBase64 = new byte[] {
- // 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
- 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
- // 'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
- 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 97, 98, 99,100,101,102,
- // 'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
- 103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,
- // 'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
- 119,120,121,122, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 43, 47, (byte)'='
- };
- private const int PAD = 64;
- public static byte[] Encode(byte[] data) {
- return Encode(data, 0, data.Length);
- }
- public static byte[] Decode(byte[] data) {
- return Decode(data, 0, data.Length);
- }
- public static byte[] Decode(byte[] encoded, int offset, int length) {
- int j, c, v;
- int bits = 0;
- int n = offset + length;
- byte[] data = new byte[(length * 3) / 4];
- v = 0;
- j = 0;
- for(int i = offset; i < n; i++) {
- c = _fromBase64[encoded[i]];
- if(c < 0) {
- if(encoded[i] == _toBase64[PAD])
- break;
- continue;
- }
- v = (v << 6) | c;
- bits += 6;
- if(bits >= 8) {
- bits -= 8;
- data[j++] = (byte) ((v >> bits) & 0xff);
- }
- }
- if(data.Length > j) {
- byte[] temp = new byte[j];
- Array.Copy(data, 0, temp, 0, j);
- data = temp;
- }
- return data;
- }
- public static byte[] Encode(byte[] data, int offset, int length) {
- byte[] encoded;
- int x1, x2, x3, x4;
- int i, j, r, n;
- r = length % 3;
- n = offset + (length - r);
- encoded = new byte[((length / 3) * 4) + (r != 0 ? 4 : 0)];
- for(i = offset, j = 0; i < n; i += 3, j += 4) {
- x1 = (data[i] & 0xfc) >> 2;
- x2 = (((data[i ] & 0x03) << 4) | ((data[i + 1] & 0xf0) >> 4));
- x3 = (((data[i + 1] & 0x0f) << 2) | ((data[i + 2] & 0xc0) >> 6));
- x4 = (data[i + 2] & 0x3f);
- encoded[j ] = _toBase64[x1];
- encoded[j + 1] = _toBase64[x2];
- encoded[j + 2] = _toBase64[x3];
- encoded[j + 3] = _toBase64[x4];
- }
- if(r != 0) {
- x1 = (data[i] & 0xfc) >> 2;
- x2 = (data[i] & 0x03) << 4;
- x3 = PAD;
- x4 = PAD;
- if(r == 2) {
- x2 |= ((data[i + 1] & 0xf0) >> 4);
- x3 = (data[i + 1] & 0x0f) << 2;
- }
- encoded[j++] = _toBase64[x1];
- encoded[j++] = _toBase64[x2];
- encoded[j++] = _toBase64[x3];
- encoded[j++] = _toBase64[x4];
- }
- return encoded;
- }
- //for test
- public static void test() {
- string t = "hernan crespo";
- string s = System.Text.Encoding.ASCII.GetString(Decode(Encode(System.Text.Encoding.ASCII.GetBytes(t))));
-
- }
- }
- }