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
|
/*
* Copyright (C) 2017 "IoT.bzh"
* Author: José Bollo <jose.bollo@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
const char base64_variant_standard[] = "+/=";
const char base64_variant_url[] = "-_=";
const char base64_variant_trunc[] = "+/";
const char base64_variant_url_trunc[] = "-_";
static char eb64(int x, const char *variant)
{
if (x < 52)
return (char)(x + (x < 26 ? 'A' : 'a'-26));
else
return x < 62 ? (char)(x + '0' - 52) : variant[x - 62];
}
char *base64_encode_array_variant(const char * const *args, size_t count, const char *variant)
{
const char *v, *s;
char *buffer, c;
size_t i, j, n;
uint16_t x;
/* compute size and allocate */
i = n = 0;
while (n < count)
i += strlen(args[n++]);
buffer = malloc(5 + ((i / 3) << 2));
if (!buffer)
return NULL;
/* encode */
v = variant ? : base64_variant_standard;
n = 0;
j = 0;
x = 0;
while (n < count) {
s = args[n++];
c = s[i = 0];
while (c) {
x = (uint16_t)((uint16_t)(x << 8) | (uint16_t)(uint8_t)c);
switch (j & 3) {
case 0:
buffer[j++] = eb64((x >> 2) & 63, v);
break;
case 1:
buffer[j++] = eb64((x >> 4) & 63, v);
break;
case 2:
buffer[j++] = eb64((x >> 6) & 63, v);
buffer[j++] = eb64(x & 63, v);
break;
}
c = s[++i];
}
}
/* pad */
if (v[2]) {
switch (j & 3) {
case 1:
buffer[j++] = eb64((x << 4) & 63, v);
buffer[j++] = v[2];
buffer[j++] = v[2];
break;
case 2:
buffer[j++] = eb64((x << 2) & 63, v);
buffer[j++] = v[2];
break;
}
}
/* done */
buffer[j] = 0;
return buffer;
}
char *base64_encode_multi_variant(const char * const *args, const char *variant)
{
size_t count;
for (count = 0 ; args[count] ; count++);
return base64_encode_array_variant(args, count, variant);
}
char *base64_encode_variant(const char *arg, const char *variant)
{
return base64_encode_array_variant(&arg, !!arg, variant);
}
|
