src/specifier.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <string.h>
  23
  24 #include "macro.h"
  25 #include "util.h"
  26 #include "specifier.h"
  27
  28 /*
  29  * Generic infrastructure for replacing %x style specifiers in
  30  * strings. Will call a callback for each replacement.
  31  *
  32  */
  33
  34 char *specifier_printf(const char *text, const Specifier table[], void *userdata) {
  35         char *r, *t;
  36         const char *f;
  37         bool percent = false;
  38         size_t l;
  39
  40         assert(text);
  41         assert(table);
  42
  43         l = strlen(text);
  44         if (!(r = new(char, l+1)))
  45                 return NULL;
  46
  47         t = r;
  48
  49         for (f = text; *f; f++, l--) {
  50
  51                 if (percent) {
  52                         if (*f == '%')
  53                                 *(t++) = '%';
  54                         else {
  55                                 const Specifier *i;
  56
  57                                 for (i = table; i->specifier; i++)
  58                                         if (i->specifier == *f)
  59                                                 break;
  60
  61                                 if (i->lookup) {
  62                                         char *n, *w;
  63                                         size_t k, j;
  64
  65                                         if (!(w = i->lookup(i->specifier, i->data, userdata))) {
  66                                                 free(r);
  67                                                 return NULL;
  68                                         }
  69
  70                                         j = t - r;
  71                                         k = strlen(w);
  72
  73                                         if (!(n = new(char, j + k + l + 1))) {
  74                                                 free(r);
  75                                                 free(w);
  76                                                 return NULL;
  77                                         }
  78
  79                                         memcpy(n, r, j);
  80                                         memcpy(n + j, w, k);
  81
  82                                         free(r);
  83                                         free(w);
  84
  85                                         r = n;
  86                                         t = n + j + k;
  87                                 } else {
  88                                         *(t++) = '%';
  89                                         *(t++) = *f;
  90                                 }
  91                         }
  92
  93                         percent = false;
  94                 } else if (*f == '%')
  95                         percent = true;
  96                 else
  97                         *(t++) = *f;
  98         }
  99
 100         *t = 0;
 101         return r;
 102 }
 103
 104 /* Generic handler for simple string replacements */
 105
 106 char* specifier_string(char specifier, void *data, void *userdata) {
 107         assert(data);
 108
 109         return strdup(strempty(data));
 110 }