stash: end commit log with a newline
[git] / interpolate.c
1 /*
2  * Copyright 2006 Jon Loeliger
3  */
4
5 #include "git-compat-util.h"
6 #include "interpolate.h"
7
8
9 void interp_set_entry(struct interp *table, int slot, const char *value)
10 {
11         char *oldval = table[slot].value;
12         char *newval = NULL;
13
14         if (oldval)
15                 free(oldval);
16
17         if (value)
18                 newval = xstrdup(value);
19
20         table[slot].value = newval;
21 }
22
23
24 void interp_clear_table(struct interp *table, int ninterps)
25 {
26         int i;
27
28         for (i = 0; i < ninterps; i++) {
29                 interp_set_entry(table, i, NULL);
30         }
31 }
32
33
34 /*
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.
39  *
40  * Example interps:
41  *    {
42  *        { "%H", "example.org"},
43  *        { "%port", "123"},
44  *        { "%%", "%"},
45  *    }
46  *
47  * Returns 0 on a successful substitution pass that fits in result,
48  * Returns a number of bytes needed to hold the full substituted
49  * string otherwise.
50  */
51
52 unsigned long interpolate(char *result, unsigned long reslen,
53                 const char *orig,
54                 const struct interp *interps, int ninterps)
55 {
56         const char *src = orig;
57         char *dest = result;
58         unsigned long newlen = 0;
59         const char *name, *value;
60         unsigned long namelen, valuelen;
61         int i;
62         char c;
63
64         memset(result, 0, reslen);
65
66         while ((c = *src)) {
67                 if (c == '%') {
68                         /* Try to match an interpolation string. */
69                         for (i = 0; i < ninterps; i++) {
70                                 name = interps[i].name;
71                                 namelen = strlen(name);
72                                 if (strncmp(src, name, namelen) == 0)
73                                         break;
74                         }
75
76                         /* Check for valid interpolation. */
77                         if (i < ninterps) {
78                                 value = interps[i].value;
79                                 valuelen = strlen(value);
80
81                                 if (newlen + valuelen + 1 < reslen) {
82                                         /* Substitute. */
83                                         strncpy(dest, value, valuelen);
84                                         dest += valuelen;
85                                 }
86                                 newlen += valuelen;
87                                 src += namelen;
88                                 continue;
89                         }
90                 }
91                 /* Straight copy one non-interpolation character. */
92                 if (newlen + 1 < reslen)
93                         *dest++ = *src;
94                 src++;
95                 newlen++;
96         }
97
98         if (newlen + 1 < reslen)
99                 return 0;
100         else
101                 return newlen + 2;
102 }