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
|
#include "base64.h"
#include "str.h"
static char *b64alpha =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
#define B64PAD '='
/* returns 0 ok, 1 illegal, -1 problem */
int b64decode(const unsigned char *in,int l,stralloc *out)
/* stralloc *out => not null terminated */
{
int p = 0;
int n;
unsigned int x;
int i, j;
char *s;
unsigned char b[3];
if (l == 0) {
if (!stralloc_copys(out,"")) return -1;
return 0;
}
while (in[l-1] == B64PAD) {
p ++;
l--;
}
n = (l + p) / 4;
i = (n * 3) - p;
if (!stralloc_ready(out,i)) return -1;
out->len = i;
s = out->s;
for (i = 0; i < n - 1; i++) {
x = 0;
for (j = 0; j < 4; j++) {
if (in[j] >= 'A' && in[j] <= 'Z')
x = (x << 6) + (unsigned int)(in[j] - 'A' + 0);
else if (in[j] >= 'a' && in[j] <= 'z')
x = (x << 6) + (unsigned int)(in[j] - 'a' + 26);
else if (in[j] >= '0' && in[j] <= '9')
x = (x << 6) + (unsigned int)(in[j] - '0' + 52);
else if (in[j] == '+')
x = (x << 6) + 62;
else if (in[j] == '/')
x = (x << 6) + 63;
else if (in[j] == '=')
x = (x << 6);
else return 1;
}
s[2] = (unsigned char)(x & 255); x >>= 8;
s[1] = (unsigned char)(x & 255); x >>= 8;
s[0] = (unsigned char)(x & 255); x >>= 8;
s += 3; in += 4;
}
x = 0;
for (j = 0; j < 4; j++) {
if (in[j] >= 'A' && in[j] <= 'Z')
x = (x << 6) + (unsigned int)(in[j] - 'A' + 0);
else if (in[j] >= 'a' && in[j] <= 'z')
x = (x << 6) + (unsigned int)(in[j] - 'a' + 26);
else if (in[j] >= '0' && in[j] <= '9')
x = (x << 6) + (unsigned int)(in[j] - '0' + 52);
else if (in[j] == '+')
x = (x << 6) + 62;
else if (in[j] == '/')
x = (x << 6) + 63;
else if (in[j] == '=')
x = (x << 6);
else return 1;
}
b[2] = (unsigned char)(x & 255); x >>= 8;
b[1] = (unsigned char)(x & 255); x >>= 8;
b[0] = (unsigned char)(x & 255); x >>= 8;
for (i = 0; i < 3 - p; i++)
s[i] = b[i];
return 0;
}
int b64encode(stralloc *in,stralloc *out)
{
unsigned char a, b, c;
int i;
char *s;
if (in->len == 0)
{
if (!stralloc_copys(out,"")) return -1;
return 0;
}
i = in->len / 3 * 4 + 4;
if (!stralloc_ready(out,i)) return -1;
s = out->s;
for (i = 0; i < in->len; i += 3) {
a = in->s[i];
b = i + 1 < in->len ? in->s[i + 1] : 0;
c = i + 2 < in->len ? in->s[i + 2] : 0;
*s++ = b64alpha[a >> 2];
*s++ = b64alpha[((a & 3 ) << 4) | (b >> 4)];
if (i + 1 >= in->len) *s++ = B64PAD;
else *s++ = b64alpha[((b & 0x0f) << 2) | (c >> 6)];
if (i + 2 >= in->len) *s++ = B64PAD;
else *s++ = b64alpha[c & 0x3f];
}
out->len = s - out->s;
return 0;
}
|
