Line | Count | Source |
1 | | #include "git-compat-util.h" |
2 | | #include "base85.h" |
3 | | |
4 | | #undef DEBUG_85 |
5 | | |
6 | | #ifdef DEBUG_85 |
7 | | #define say(a) fprintf(stderr, a) |
8 | | #define say1(a,b) fprintf(stderr, a, b) |
9 | | #define say2(a,b,c) fprintf(stderr, a, b, c) |
10 | | #else |
11 | 0 | #define say(a) do { /* nothing */ } while (0) |
12 | 0 | #define say1(a,b) do { /* nothing */ } while (0) |
13 | 0 | #define say2(a,b,c) do { /* nothing */ } while (0) |
14 | | #endif |
15 | | |
16 | | static const char en85[] = { |
17 | | '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', |
18 | | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', |
19 | | 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', |
20 | | 'U', 'V', 'W', 'X', 'Y', 'Z', |
21 | | 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', |
22 | | 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', |
23 | | 'u', 'v', 'w', 'x', 'y', 'z', |
24 | | '!', '#', '$', '%', '&', '(', ')', '*', '+', '-', |
25 | | ';', '<', '=', '>', '?', '@', '^', '_', '`', '{', |
26 | | '|', '}', '~' |
27 | | }; |
28 | | |
29 | | static char de85[256]; |
30 | | static void prep_base85(void) |
31 | 0 | { |
32 | 0 | if (de85['Z']) |
33 | 0 | return; |
34 | 0 | for (size_t i = 0; i < ARRAY_SIZE(en85); i++) { |
35 | 0 | int ch = en85[i]; |
36 | 0 | de85[ch] = i + 1; |
37 | 0 | } |
38 | 0 | } |
39 | | |
40 | | int decode_85(char *dst, const char *buffer, int len) |
41 | 0 | { |
42 | 0 | prep_base85(); |
43 | |
|
44 | 0 | say2("decode 85 <%.*s>", len / 4 * 5, buffer); |
45 | 0 | while (len) { |
46 | 0 | unsigned acc = 0; |
47 | 0 | int de, cnt = 4; |
48 | 0 | unsigned char ch; |
49 | 0 | do { |
50 | 0 | ch = *buffer++; |
51 | 0 | de = de85[ch]; |
52 | 0 | if (--de < 0) |
53 | 0 | return error("invalid base85 alphabet %c", ch); |
54 | 0 | acc = acc * 85 + de; |
55 | 0 | } while (--cnt); |
56 | 0 | ch = *buffer++; |
57 | 0 | de = de85[ch]; |
58 | 0 | if (--de < 0) |
59 | 0 | return error("invalid base85 alphabet %c", ch); |
60 | | /* Detect overflow. */ |
61 | 0 | if (0xffffffff / 85 < acc || |
62 | 0 | 0xffffffff - de < (acc *= 85)) |
63 | 0 | return error("invalid base85 sequence %.5s", buffer-5); |
64 | 0 | acc += de; |
65 | 0 | say1(" %08x", acc); |
66 | |
|
67 | 0 | cnt = (len < 4) ? len : 4; |
68 | 0 | len -= cnt; |
69 | 0 | do { |
70 | 0 | acc = (acc << 8) | (acc >> 24); |
71 | 0 | *dst++ = acc; |
72 | 0 | } while (--cnt); |
73 | 0 | } |
74 | 0 | say("\n"); |
75 | |
|
76 | 0 | return 0; |
77 | 0 | } |
78 | | |
79 | | void encode_85(char *buf, const unsigned char *data, int bytes) |
80 | 0 | { |
81 | 0 | say("encode 85"); |
82 | 0 | while (bytes) { |
83 | 0 | unsigned acc = 0; |
84 | 0 | int cnt; |
85 | 0 | for (cnt = 24; cnt >= 0; cnt -= 8) { |
86 | 0 | unsigned ch = *data++; |
87 | 0 | acc |= ch << cnt; |
88 | 0 | if (--bytes == 0) |
89 | 0 | break; |
90 | 0 | } |
91 | 0 | say1(" %08x", acc); |
92 | 0 | for (cnt = 4; cnt >= 0; cnt--) { |
93 | 0 | int val = acc % 85; |
94 | 0 | acc /= 85; |
95 | 0 | buf[cnt] = en85[val]; |
96 | 0 | } |
97 | 0 | buf += 5; |
98 | 0 | } |
99 | 0 | say("\n"); |
100 | |
|
101 | 0 | *buf = 0; |
102 | 0 | } |
103 | | |
104 | | #ifdef DEBUG_85 |
105 | | int main(int ac, char **av) |
106 | | { |
107 | | char buf[1024]; |
108 | | |
109 | | if (!strcmp(av[1], "-e")) { |
110 | | int len = strlen(av[2]); |
111 | | encode_85(buf, av[2], len); |
112 | | if (len <= 26) len = len + 'A' - 1; |
113 | | else len = len + 'a' - 26 - 1; |
114 | | printf("encoded: %c%s\n", len, buf); |
115 | | return 0; |
116 | | } |
117 | | if (!strcmp(av[1], "-d")) { |
118 | | int len = *av[2]; |
119 | | if ('A' <= len && len <= 'Z') len = len - 'A' + 1; |
120 | | else len = len - 'a' + 26 + 1; |
121 | | decode_85(buf, av[2]+1, len); |
122 | | printf("decoded: %.*s\n", len, buf); |
123 | | return 0; |
124 | | } |
125 | | if (!strcmp(av[1], "-t")) { |
126 | | char t[4] = { -1,-1,-1,-1 }; |
127 | | encode_85(buf, t, 4); |
128 | | printf("encoded: D%s\n", buf); |
129 | | return 0; |
130 | | } |
131 | | } |
132 | | #endif |