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
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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
|
/* <!-- copyright */
/*
* aria2 - a simple utility for downloading files faster
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* copyright --> */
#include "Base64.h"
string Base64::part_encode(const string& subplain)
{
static char base64_table[64] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/',
};
int shift = 2;
char carry = 0;
bool ignore_flag = false;
string crypted;
for(unsigned int index = 0; index < subplain.size(); ++index) {
if(ignore_flag) {
crypted += '=';
} else {
char cur = subplain.at(index) >> shift | carry;
if(subplain.at(index) == 0) ignore_flag = true;
carry = (subplain.at(index) << (6-shift)) & 0x3F;
shift += 2;
crypted += base64_table[(unsigned int)cur];
}
}
if(subplain.at(subplain.size()-1) == 0) {
crypted += '=';
} else {
char cur = subplain.at(subplain.size()-1) & 0x3F;
crypted += base64_table[(unsigned int)cur];
}
return crypted;
}
string Base64::encode(string plain)
{
int remainder = plain.size() % 3;
if( remainder ) remainder = 3-remainder;
for(int i = 0; i < remainder; ++i) plain += (char)0;
string crypted;
int start_pos = 0;
for(unsigned int index = 0; plain.size() > index; index += 3) {
string subplain = plain.substr(start_pos, 3);
string subcrypted = part_encode(subplain);
start_pos += 3;
crypted += subcrypted;
}
return crypted;
}
char Base64::getValue(char ch)
{
char retch;
if(ch >= 'A' && ch <= 'Z') {
retch = ch-'A';
} else if(ch >= 'a' && ch <= 'z') {
retch = ch-'a'+26;
} else if(ch >= '0' && ch <= '9') {
retch = ch-'0'+52;
} else if(ch == '+') {
retch = 62;
} else if(ch == '/') {
retch = 63;
} else {
retch = 0;
}
return retch;
}
string Base64::part_decode(const string& subCrypted)
{
int shift = 2;
string plain;
for(unsigned int index = 0; index < subCrypted.size()-1; ++index) {
if(subCrypted.at(index) == '=') break;
char cur = getValue(subCrypted.at(index)) << shift;
char carry = getValue(subCrypted.at(index+1)) >> (6-shift);
shift += 2;
plain += cur | carry;
}
return plain;
}
string Base64::decode(string crypted)
{
string plain;
int sIndex = 0;
for(int index = 0; crypted.size() > (unsigned int)index; index +=4) {
string subCrypted = crypted.substr(sIndex, 4);
string subPlain = part_decode(subCrypted);
sIndex += 4;
plain += subPlain;
}
return plain;
}
|
