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49ba83fb JL |
1 | /* |
2 | * Copyright 2006 Jon Loeliger | |
3 | */ | |
4 | ||
5 | #include <string.h> | |
6 | ||
7 | #include "interpolate.h" | |
8 | ||
9 | ||
10 | /* | |
11 | * Convert a NUL-terminated string in buffer orig | |
12 | * into the supplied buffer, result, whose length is reslen, | |
13 | * performing substitutions on %-named sub-strings from | |
14 | * the table, interps, with ninterps entries. | |
15 | * | |
16 | * Example interps: | |
17 | * { | |
18 | * { "%H", "example.org"}, | |
19 | * { "%port", "123"}, | |
20 | * { "%%", "%"}, | |
21 | * } | |
22 | * | |
23 | * Returns 1 on a successful substitution pass that fits in result, | |
24 | * Returns 0 on a failed or overflowing substitution pass. | |
25 | */ | |
26 | ||
27 | int interpolate(char *result, int reslen, | |
28 | char *orig, | |
29 | struct interp *interps, int ninterps) | |
30 | { | |
31 | char *src = orig; | |
32 | char *dest = result; | |
33 | int newlen = 0; | |
34 | char *name, *value; | |
35 | int namelen, valuelen; | |
36 | int i; | |
37 | char c; | |
38 | ||
39 | memset(result, 0, reslen); | |
40 | ||
41 | while ((c = *src) && newlen < reslen - 1) { | |
42 | if (c == '%') { | |
43 | /* Try to match an interpolation string. */ | |
44 | for (i = 0; i < ninterps; i++) { | |
45 | name = interps[i].name; | |
46 | namelen = strlen(name); | |
47 | if (strncmp(src, name, namelen) == 0) { | |
48 | break; | |
49 | } | |
50 | } | |
51 | ||
52 | /* Check for valid interpolation. */ | |
53 | if (i < ninterps) { | |
54 | value = interps[i].value; | |
55 | valuelen = strlen(value); | |
56 | ||
57 | if (newlen + valuelen < reslen - 1) { | |
58 | /* Substitute. */ | |
59 | strncpy(dest, value, valuelen); | |
60 | newlen += valuelen; | |
61 | dest += valuelen; | |
62 | src += namelen; | |
63 | } else { | |
64 | /* Something's not fitting. */ | |
65 | return 0; | |
66 | } | |
67 | ||
68 | } else { | |
69 | /* Skip bogus interpolation. */ | |
70 | *dest++ = *src++; | |
71 | newlen++; | |
72 | } | |
73 | ||
74 | } else { | |
75 | /* Straight copy one non-interpolation character. */ | |
76 | *dest++ = *src++; | |
77 | newlen++; | |
78 | } | |
79 | } | |
80 | ||
81 | return newlen < reslen - 1; | |
82 | } |