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
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
// file : libbutl/base64.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef __cpp_modules
#include <libbutl/base64.mxx>
#endif
// C includes.
#ifndef __cpp_lib_modules
#include <string>
#include <vector>
#include <cstddef> // size_t
#include <istream>
#include <ostream>
#include <iterator> // {istreambuf, ostreambuf, back_insert}_iterator
#include <stdexcept> // invalid_argument
#endif
// Other includes.
#ifdef __cpp_modules
module butl.base64;
// Only imports additional to interface.
#ifdef __clang__
#ifdef __cpp_lib_modules
import std.core;
import std.io;
#endif
#endif
#endif
using namespace std;
namespace butl
{
static const char codes[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
// base64-encode the data in the iterator range [i, e). Write the encoded
// data starting at the iterator position o.
//
template <typename I, typename O>
static void
base64_encode (I& i, const I& e, O& o)
{
const size_t un (65); // Non-existing index of the codes string.
for (size_t n (0); i != e; ++n)
{
if (n && n % 19 == 0)
*o++ = '\n'; // Split into lines, like the base64 utility does.
auto next = [&i] () {return static_cast<unsigned char> (*i++);};
unsigned char c (next ());
size_t i1 ((c >> 2) & 0x3F);
size_t i2 ((c << 4) & 0x30);
size_t i3 (un);
if (i != e)
{
c = next ();
i2 |= (c >> 4) & 0xF;
i3 = (c << 2) & 0x3C;
}
size_t i4 (un);
if (i != e)
{
c = next ();
i3 |= (c >> 6) & 0x3;
i4 = c & 0x3F;
}
*o++ = codes[i1];
*o++ = codes[i2];
*o++ = i3 == un ? '=' : codes[i3];
*o++ = i4 == un ? '=' : codes[i4];
}
}
static char
index (char c)
{
switch (c)
{
case '/': return 63;
case '+': return 62;
default:
{
if (c >= 'A' && c <= 'Z')
return c - 'A';
else if (c >= 'a' && c <= 'z')
return c - 'a' + 26;
else if (c >= '0' && c <= '9')
return c - '0' + 52;
else
throw invalid_argument ("invalid input");
}
}
}
// base64-decode the data in the iterator range [i, e). Write the decoded
// data starting at the iterator position o. Throw invalid_argument if the
// input data is invalid.
//
template <typename I, typename O>
static void
base64_decode (I& i, const I& e, O& o)
{
auto bad = []() {throw invalid_argument ("invalid input");};
auto next = [&i, &e, &bad]() -> char
{
if (i == e)
bad ();
return *i++;
};
while (i != e)
{
char c (next ());
if (c == '\n') // @@ Should we check for '\r' as well ?
continue;
char i1 = index (c);
char i2 = index (next ());
*o++ = (i1 << 2) | (i2 >> 4);
c = next ();
if (c == '=')
{
if (next () != '=' || i != e)
bad ();
}
else
{
char i3 = index (c);
*o++ = (i2 << 4) | (i3 >> 2);
c = next ();
if (c == '=')
{
if (i != e)
bad ();
}
else
*o++ = (i3 << 6) | index (c);
}
}
}
string
base64_encode (istream& is)
{
if (!is.good ())
throw invalid_argument ("bad stream");
string r;
istreambuf_iterator<char> i (is);
back_insert_iterator<string> o (r);
base64_encode (i, istreambuf_iterator<char> (), o);
is.setstate (istream::eofbit);
return r;
}
void
base64_encode (ostream& os, istream& is)
{
if (!os.good () || !is.good ())
throw invalid_argument ("bad stream");
istreambuf_iterator<char> i (is);
ostreambuf_iterator<char> o (os);
base64_encode (i, istreambuf_iterator<char> (), o);
if (o.failed ())
os.setstate (istream::badbit);
is.setstate (istream::eofbit);
}
string
base64_encode (const vector<char>& v)
{
string r;
back_insert_iterator<string> o (r);
auto i (v.begin ());
base64_encode (i, v.end (), o);
return r;
}
void
base64_decode (ostream& os, istream& is)
{
if (!os.good () || !is.good ())
throw invalid_argument ("bad stream");
istreambuf_iterator<char> i (is);
ostreambuf_iterator<char> o (os);
base64_decode (i, istreambuf_iterator<char> (), o);
if (o.failed ())
os.setstate (istream::badbit);
is.setstate (istream::eofbit);
}
void
base64_decode (ostream& os, const string& s)
{
if (!os.good ())
throw invalid_argument ("bad stream");
ostreambuf_iterator<char> o (os);
auto i (s.cbegin ());
base64_decode (i, s.cend (), o);
if (o.failed ())
os.setstate (istream::badbit);
}
vector<char>
base64_decode (const string& s)
{
vector<char> r;
back_insert_iterator<vector<char>> o (r);
auto i (s.cbegin ());
base64_decode (i, s.cend (), o);
return r;
}
}
|
