builtin-apply: stronger indent-with-on-tab fixing
[git/jbf-maint.git] / interpolate.c
blob6ef53f246511a1943e375d5d5913a4ec52e2c663
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 if (oldval)
15 free(oldval);
17 if (value)
18 newval = xstrdup(value);
20 table[slot].value = newval;
24 void interp_clear_table(struct interp *table, int ninterps)
26 int i;
28 for (i = 0; i < ninterps; i++) {
29 interp_set_entry(table, i, NULL);
35 * Convert a NUL-terminated string in buffer orig
36 * into the supplied buffer, result, whose length is reslen,
37 * performing substitutions on %-named sub-strings from
38 * the table, interps, with ninterps entries.
40 * Example interps:
41 * {
42 * { "%H", "example.org"},
43 * { "%port", "123"},
44 * { "%%", "%"},
45 * }
47 * Returns the length of the substituted string (not including the final \0).
48 * Like with snprintf, if the result is >= reslen, then it overflowed.
51 unsigned long interpolate(char *result, unsigned long reslen,
52 const char *orig,
53 const struct interp *interps, int ninterps)
55 const char *src = orig;
56 char *dest = result;
57 unsigned long newlen = 0;
58 const char *name, *value;
59 unsigned long namelen, valuelen;
60 int i;
61 char c;
63 while ((c = *src)) {
64 if (c == '%') {
65 /* Try to match an interpolation string. */
66 for (i = 0; i < ninterps; i++) {
67 name = interps[i].name;
68 namelen = strlen(name);
69 if (strncmp(src, name, namelen) == 0)
70 break;
73 /* Check for valid interpolation. */
74 if (i < ninterps) {
75 value = interps[i].value;
76 if (!value) {
77 src += namelen;
78 continue;
81 valuelen = strlen(value);
82 if (newlen + valuelen < reslen) {
83 /* Substitute. */
84 memcpy(dest, value, valuelen);
85 dest += valuelen;
87 newlen += valuelen;
88 src += namelen;
89 continue;
92 /* Straight copy one non-interpolation character. */
93 if (newlen + 1 < reslen)
94 *dest++ = *src;
95 src++;
96 newlen++;
99 /* XXX: the previous loop always keep room for the ending NUL,
100 we just need to check if there was room for a NUL in the first place */
101 if (reslen > 0)
102 *dest = '\0';
103 return newlen;