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
|
/*
* Output a base64 string.
*
* Options include:
* - Character 62 and 63;
* - To pad or not to pad.
*/
#include <inttypes.h>
#include <base64.h>
size_t genbase64(char *output, const void *input, size_t size, int flags)
{
static char charz[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+_";
uint8_t buf[3];
int j;
const uint8_t *p;
char *q;
uint32_t bv;
int left = size;
charz[62] = (char)flags;
charz[63] = (char)(flags >> 8);
p = input;
q = output;
while (left > 0) {
if (left < 3) {
buf[0] = p[0];
buf[1] = (left > 1) ? p[1] : 0;
buf[2] = 0;
p = buf;
}
bv = (p[0] << 16) | (p[1] << 8) | p[2];
p += 3;
left -= 3;
for (j = 0; j < 4; j++) {
*q++ = charz[(bv >> 18) & 0x3f];
bv <<= 6;
}
}
switch (left) {
case -1:
if (flags & BASE64_PAD)
q[-1] = '=';
else
q--;
break;
case -2:
if (flags & BASE64_PAD)
q[-2] = q[-1] = '=';
else
q -= 2;
break;
default:
break;
}
*q = '\0';
return q - output;
}
#ifdef TEST
#include <stdio.h>
#include <string.h>
int main(int argc, char *argv[])
{
int i;
char buf[4096];
int len, bytes;
for (i = 1; i < argc; i++) {
printf("Original: \"%s\"\n", argv[i]);
len = strlen(argv[i]);
bytes = genbase64(buf, argv[i], len, BASE64_MIME | BASE64_PAD);
printf(" MIME: \"%s\" (%d)\n", buf, bytes);
bytes = genbase64(buf, argv[i], len, BASE64_SAFE);
printf(" Safe: \"%s\" (%d)\n", buf, bytes);
}
return 0;
}
#endif
|
