src/substitution.c

   1 /*
   2  * charybdis: an advanced ircd
   3  * substitution.c: parses substitution-keyword expansions
   4  *
   5  * Copyright (c) 2006-2007 William Pitcock <nenolod@nenolod.net>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are
   9  * met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright notice,
  12  *    this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * 3. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  25  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  26  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  27  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  29  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31  * POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  * $Id$
  34  */
  35
  36 #include "stdinc.h"
  37 #include "s_user.h"
  38 #include "irc_string.h"
  39
  40 /*
  41  * Simple mappings for $foo -> 'bar'.
  42  * Everything is a string, so typing doesn't really matter too
  43  * horribly much right now.
  44  */
  45 struct substitution_variable
  46 {
  47         char *name;
  48         char *value;
  49 };
  50
  51 /*
  52  * substitution_append_var
  53  *
  54  * Inputs       - A variable list (rb_dlink_list), name -> value for mapping to make
  55  * Output       - none
  56  * Side Effects - Adds a name->value mapping to a list.
  57  */
  58 void substitution_append_var(rb_dlink_list *varlist, const char *name, const char *value)
  59 {
  60         struct substitution_variable *tmp = rb_malloc(sizeof(struct substitution_variable));
  61
  62         tmp->name = rb_strdup(name);
  63         tmp->value = rb_strdup(value);
  64
  65         rb_dlinkAddAlloc(tmp, varlist);
  66 }
  67
  68 /*
  69  * substitution_free
  70  *
  71  * Inputs       - A rb_dlink_list of markup variables to free.
  72  * Outputs      - none
  73  * Side Effects - Empties a list of markup variables.
  74  */
  75 void substitution_free(rb_dlink_list *varlist)
  76 {
  77         rb_dlink_node *nptr, *nptr2;
  78
  79         RB_DLINK_FOREACH_SAFE(nptr, nptr2, varlist->head)
  80         {
  81                 struct substitution_variable *tmp = (struct substitution_variable *) nptr->data;
  82
  83                 rb_dlinkDelete(nptr, varlist);
  84                 rb_free(tmp->name);
  85                 rb_free(tmp->value);
  86                 rb_free(tmp);
  87         }
  88 }
  89
  90 /*
  91  * substitution_parse
  92  *
  93  * Inputs       - A markup string, rb_dlink-list of markup values
  94  * Output       - A string which has been markup-replaced.
  95  * Side Effects - Strings larger than BUFSIZE are terminated.
  96  */
  97 char *substitution_parse(const char *fmt, rb_dlink_list *varlist)
  98 {
  99         static char buf[BUFSIZE];
 100         const char *ptr;
 101         char *bptr = buf;
 102
 103         for (ptr = fmt; *ptr != '\0' && bptr - buf < BUFSIZE; ptr++)
 104                 if (*ptr != '$')
 105                         *bptr++ = *ptr;
 106                 else if (*(ptr + 1) == '{')
 107                 {
 108                         static char varname[BUFSIZE];
 109                         char *vptr = varname;
 110                         const char *pptr;
 111                         rb_dlink_node *nptr;
 112
 113                         *vptr = '\0';
 114
 115                         /* break out ${var} */
 116                         for (pptr = ptr + 2; *pptr != '\0'; pptr++)
 117                         {
 118                                 if (*pptr != '}')
 119                                         *vptr++ = *pptr;
 120                                 else
 121                                 {
 122                                         *vptr++ = '\0';
 123                                         break;
 124                                 }
 125                         }
 126
 127                         s_assert(*varname != '\0');
 128                         s_assert(*pptr != '\0');
 129
 130                         /* advance ptr by length of variable */
 131                         ptr += (pptr - ptr);
 132
 133                         RB_DLINK_FOREACH(nptr, varlist->head)
 134                         {
 135                                 struct substitution_variable *val = (struct substitution_variable *) nptr->data;
 136
 137                                 if (!strcasecmp(varname, val->name))
 138                                 {
 139                                         strlcpy(bptr, val->value, BUFSIZE - (bptr - buf));
 140                                         bptr += strlen(val->value);
 141                                         break;
 142                                 }
 143                         }
 144                 }
 145
 146         *bptr = '\0';
 147         return buf;
 148 }