|
|
base64.c - ics2txt - convert icalendar .ics file to plain text |
|
|
 |
git clone git://bitreich.org/ics2txt git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/ics2txt (git://bitreich.org) |
|
|
 |
Log |
|
|
|
Files |
|
|
|
Refs |
|
|
|
Tags |
|
|
|
README |
|
|
|
--- |
|
|
|
base64.c (3039B) |
|
|
|
--- |
|
|
|
1 #include "base64.h" |
|
|
|
2 #include <assert.h> |
|
|
|
3 #include <stddef.h> |
|
|
|
4 #include <stdint.h> |
|
|
|
5 #include <string.h> |
|
|
|
6 |
|
|
|
7 static char encode_map[64] = |
|
|
|
8 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
|
|
|
9 |
|
|
|
10 void |
|
|
|
11 base64_encode(char const *s, size_t slen, char *d, size_t *dlen) |
|
|
|
12 { |
|
|
|
13 char const *sbeg = s, *send = s + slen, *dbeg = d; |
|
|
|
14 unsigned char x; |
|
|
|
15 |
|
|
|
16 while (s < send) { |
|
|
|
17 switch ((s - sbeg) % 3) { |
|
|
|
18 case 0: /* AAAAAABB bbbbcccc ccdddddd */ |
|
|
|
19 assert((size_t)(d - dbeg) + 1 < *dlen); |
|
|
|
20 *d++ = encode_map[*s >> 2]; |
|
|
|
21 x = *s << 4 & 0x3f; |
|
|
|
22 break; |
|
|
|
23 case 1: /* aaaaaabb BBBBCCCC ccdddddd */ |
|
|
|
24 assert((size_t)(d - dbeg) + 1 < *dlen); |
|
|
|
25 *d++ = encode_map[x | (*s >> 4)]; |
|
|
|
26 x = (*s << 2) & 0x3f; |
|
|
|
27 break; |
|
|
|
28 case 2: /* aaaaaabb bbbbcccc CCDDDDDD */ |
|
|
|
29 assert((size_t)(d - dbeg) + 2 < *dlen); |
|
|
|
30 *d++ = encode_map[x | (*s >> 6)]; |
|
|
|
31 *d++ = encode_map[*s & 0x3f]; |
|
|
|
32 break; |
|
|
|
33 } |
|
|
|
34 s++; |
|
|
|
35 } |
|
|
|
36 |
|
|
|
37 /* flush extra content in 'x' */ |
|
|
|
38 assert((size_t)(d - dbeg) + 1 < *dlen); |
|
|
|
39 if ((s - sbeg) % 3 != 2) |
|
|
|
40 *d++ = encode_map[x]; |
|
|
|
41 |
|
|
|
42 /* pad the end with '=' */ |
|
|
|
43 while ((d - dbeg) % 4 != 0) { |
|
|
|
44 assert((size_t)(d - dbeg) + 1 < *dlen); |
|
|
|
45 *d++ = '='; |
|
|
|
46 } |
|
|
|
47 |
|
|
|
48 *dlen = d - dbeg; |
|
|
|
49 } |
|
|
|
50 |
|
|
|
51 static int8_t decode_map[256] = { |
|
|
|
52 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
53 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
54 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, |
|
|
|
55 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 0, -1, -1, |
|
|
|
56 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, |
|
|
|
57 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, |
|
|
|
58 -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, |
|
|
|
59 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, |
|
|
|
60 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
61 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
62 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
63 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
64 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
65 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
66 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
67 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
|
|
|
68 }; |
|
|
|
69 |
|
|
|
70 int |
|
|
|
71 base64_decode(char const *s, size_t *slen, char *d, size_t *dlen) |
|
|
|
72 { |
|
|
|
73 char const *sbeg = s, *send = sbeg + *slen, *dbeg = d; |
|
|
|
74 |
|
|
|
75 for (; s + 3 < send; s += 4) { |
|
|
|
76 int8_t x0 = decode_map[(unsigned)s[0]]; |
|
|
|
77 int8_t x1 = decode_map[(unsigned)s[1]]; |
|
|
|
78 int8_t x2 = decode_map[(unsigned)s[2]]; |
|
|
|
79 int8_t x3 = decode_map[(unsigned)s[3]]; |
|
|
|
80 uint32_t x = (x0 << 18) | (x1 << 12) | (x2 << 6) | (x3 << 0); |
|
|
|
81 |
|
|
|
82 assert((size_t)(d - dbeg) + 3 < *dlen); |
|
|
|
83 *d++ = x >> 16; |
|
|
|
84 *d++ = x >> 8 & 0xff; |
|
|
|
85 *d++ = x & 0xff; |
|
|
|
86 |
|
|
|
87 /* only "xxxx" or "xxx=" or "xx==" allowed */ |
|
|
|
88 if (s[0] == '=' || s[1] == '=' || (s[2] == '=' && s[3] != '=')) |
|
|
|
89 return -2; |
|
|
|
90 if (s[2] == '=') |
|
|
|
91 d--; |
|
|
|
92 if (s[3] == '=') { |
|
|
|
93 d--; |
|
|
|
94 break; |
|
|
|
95 } |
|
|
|
96 |
|
|
|
97 if (x0 < 0 || x1 < 0 || x2 < 0 || x3 < 0) |
|
|
|
98 return -1; |
|
|
|
99 } |
|
|
|
100 |
|
|
|
101 *slen = s - sbeg; |
|
|
|
102 *dlen = d - dbeg; |
|
|
|
103 return 0; |
|
|
|
104 } |
|