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Commit | Line | Data |
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0660626c JH |
1 | #include "cache.h" |
2 | ||
3 | #undef DEBUG_85 | |
4 | ||
5 | #ifdef DEBUG_85 | |
6 | #define say(a) fprintf(stderr, a) | |
7 | #define say1(a,b) fprintf(stderr, a, b) | |
8 | #define say2(a,b,c) fprintf(stderr, a, b, c) | |
9 | #else | |
10 | #define say(a) do {} while(0) | |
11 | #define say1(a,b) do {} while(0) | |
12 | #define say2(a,b,c) do {} while(0) | |
13 | #endif | |
14 | ||
15 | static const char en85[] = { | |
16 | '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', | |
17 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', | |
18 | 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', | |
19 | 'U', 'V', 'W', 'X', 'Y', 'Z', | |
20 | 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', | |
21 | 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', | |
22 | 'u', 'v', 'w', 'x', 'y', 'z', | |
23 | '!', '#', '$', '%', '&', '(', ')', '*', '+', '-', | |
24 | ';', '<', '=', '>', '?', '@', '^', '_', '`', '{', | |
25 | '|', '}', '~' | |
26 | }; | |
27 | ||
28 | static char de85[256]; | |
29 | static void prep_base85(void) | |
30 | { | |
31 | int i; | |
32 | if (de85['Z']) | |
33 | return; | |
34 | for (i = 0; i < ARRAY_SIZE(en85); i++) { | |
35 | int ch = en85[i]; | |
36 | de85[ch] = i + 1; | |
37 | } | |
38 | } | |
39 | ||
f9815772 | 40 | int decode_85(char *dst, const char *buffer, int len) |
0660626c JH |
41 | { |
42 | prep_base85(); | |
43 | ||
44 | say2("decode 85 <%.*s>", len/4*5, buffer); | |
45 | while (len) { | |
46 | unsigned acc = 0; | |
addaacab NP |
47 | int de, cnt = 4; |
48 | unsigned char ch; | |
49 | do { | |
50 | ch = *buffer++; | |
51 | de = de85[ch]; | |
52 | if (--de < 0) | |
0660626c | 53 | return error("invalid base85 alphabet %c", ch); |
0660626c | 54 | acc = acc * 85 + de; |
addaacab NP |
55 | } while (--cnt); |
56 | ch = *buffer++; | |
57 | de = de85[ch]; | |
58 | if (--de < 0) | |
59 | return error("invalid base85 alphabet %c", ch); | |
60 | /* | |
61 | * Detect overflow. The largest | |
62 | * 5-letter possible is "|NsC0" to | |
63 | * encode 0xffffffff, and "|NsC" gives | |
64 | * 0x03030303 at this point (i.e. | |
65 | * 0xffffffff = 0x03030303 * 85). | |
66 | */ | |
67 | if (0x03030303 < acc || | |
68 | 0xffffffff - de < (acc *= 85)) | |
69 | error("invalid base85 sequence %.5s", buffer-5); | |
70 | acc += de; | |
0660626c | 71 | say1(" %08x", acc); |
addaacab NP |
72 | |
73 | cnt = (len < 4) ? len : 4; | |
74 | len -= cnt; | |
75 | do { | |
76 | acc = (acc << 8) | (acc >> 24); | |
77 | *dst++ = acc; | |
78 | } while (--cnt); | |
0660626c JH |
79 | } |
80 | say("\n"); | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
f9815772 | 85 | void encode_85(char *buf, const unsigned char *data, int bytes) |
0660626c JH |
86 | { |
87 | prep_base85(); | |
88 | ||
89 | say("encode 85"); | |
90 | while (bytes) { | |
91 | unsigned acc = 0; | |
92 | int cnt; | |
addaacab | 93 | for (cnt = 24; cnt >= 0; cnt -= 8) { |
0660626c | 94 | int ch = *data++; |
addaacab NP |
95 | acc |= ch << cnt; |
96 | if (--bytes == 0) | |
97 | break; | |
0660626c JH |
98 | } |
99 | say1(" %08x", acc); | |
addaacab | 100 | for (cnt = 4; cnt >= 0; cnt--) { |
0660626c JH |
101 | int val = acc % 85; |
102 | acc /= 85; | |
addaacab | 103 | buf[cnt] = en85[val]; |
0660626c JH |
104 | } |
105 | buf += 5; | |
106 | } | |
107 | say("\n"); | |
108 | ||
109 | *buf = 0; | |
110 | } | |
111 | ||
112 | #ifdef DEBUG_85 | |
113 | int main(int ac, char **av) | |
114 | { | |
115 | char buf[1024]; | |
116 | ||
117 | if (!strcmp(av[1], "-e")) { | |
118 | int len = strlen(av[2]); | |
119 | encode_85(buf, av[2], len); | |
120 | if (len <= 26) len = len + 'A' - 1; | |
121 | else len = len + 'a' - 26 + 1; | |
122 | printf("encoded: %c%s\n", len, buf); | |
123 | return 0; | |
124 | } | |
125 | if (!strcmp(av[1], "-d")) { | |
126 | int len = *av[2]; | |
127 | if ('A' <= len && len <= 'Z') len = len - 'A' + 1; | |
128 | else len = len - 'a' + 26 + 1; | |
129 | decode_85(buf, av[2]+1, len); | |
130 | printf("decoded: %.*s\n", len, buf); | |
131 | return 0; | |
132 | } | |
133 | if (!strcmp(av[1], "-t")) { | |
134 | char t[4] = { -1,-1,-1,-1 }; | |
135 | encode_85(buf, t, 4); | |
136 | printf("encoded: D%s\n", buf); | |
137 | return 0; | |
138 | } | |
139 | } | |
140 | #endif |