Windows ANSI - hook write()
[git/mingw/4msysgit/peterh.git] / interpolate.c
blob7f03bd99c5b66afa6cc7fa11a2430301a3042656
1 /*
2 * Copyright 2006 Jon Loeliger
3 */
5 #include "git-compat-util.h"
6 #include "interpolate.h"
9 void interp_set_entry(struct interp *table, int slot, const char *value)
11 char *oldval = table[slot].value;
12 char *newval = NULL;
14 free(oldval);
16 if (value)
17 newval = xstrdup(value);
19 table[slot].value = newval;
23 void interp_clear_table(struct interp *table, int ninterps)
25 int i;
27 for (i = 0; i < ninterps; i++) {
28 interp_set_entry(table, i, NULL);
34 * Convert a NUL-terminated string in buffer orig
35 * into the supplied buffer, result, whose length is reslen,
36 * performing substitutions on %-named sub-strings from
37 * the table, interps, with ninterps entries.
39 * Example interps:
40 * {
41 * { "%H", "example.org"},
42 * { "%port", "123"},
43 * { "%%", "%"},
44 * }
46 * Returns the length of the substituted string (not including the final \0).
47 * Like with snprintf, if the result is >= reslen, then it overflowed.
50 unsigned long interpolate(char *result, unsigned long reslen,
51 const char *orig,
52 const struct interp *interps, int ninterps)
54 const char *src = orig;
55 char *dest = result;
56 unsigned long newlen = 0;
57 const char *name, *value;
58 unsigned long namelen, valuelen;
59 int i;
60 char c;
62 while ((c = *src)) {
63 if (c == '%') {
64 /* Try to match an interpolation string. */
65 for (i = 0; i < ninterps; i++) {
66 name = interps[i].name;
67 namelen = strlen(name);
68 if (strncmp(src, name, namelen) == 0)
69 break;
72 /* Check for valid interpolation. */
73 if (i < ninterps) {
74 value = interps[i].value;
75 if (!value) {
76 src += namelen;
77 continue;
80 valuelen = strlen(value);
81 if (newlen + valuelen < reslen) {
82 /* Substitute. */
83 memcpy(dest, value, valuelen);
84 dest += valuelen;
86 newlen += valuelen;
87 src += namelen;
88 continue;
91 /* Straight copy one non-interpolation character. */
92 if (newlen + 1 < reslen)
93 *dest++ = *src;
94 src++;
95 newlen++;
98 /* XXX: the previous loop always keep room for the ending NUL,
99 we just need to check if there was room for a NUL in the first place */
100 if (reslen > 0)
101 *dest = '\0';
102 return newlen;