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 "match.h"
  39 #include "substitution.h"
  40
  41 /*
  42  * Simple mappings for $foo -> 'bar'.
  43  * Everything is a string, so typing doesn't really matter too
  44  * horribly much right now.
  45  */
  46 struct substitution_variable
  47 {
  48         char *name;
  49         char *value;
  50 };
  51
  52 /*
  53  * substitution_append_var
  54  *
  55  * Inputs       - A variable list (rb_dlink_list), name -> value for mapping to make
  56  * Output       - none
  57  * Side Effects - Adds a name->value mapping to a list.
  58  */
  59 void substitution_append_var(rb_dlink_list *varlist, const char *name, const char *value)
  60 {
  61         struct substitution_variable *tmp = rb_malloc(sizeof(struct substitution_variable));
  62
  63         tmp->name = rb_strdup(name);
  64         tmp->value = rb_strdup(value);
  65
  66         rb_dlinkAddAlloc(tmp, varlist);
  67 }
  68
  69 /*
  70  * substitution_free
  71  *
  72  * Inputs       - A rb_dlink_list of markup variables to free.
  73  * Outputs      - none
  74  * Side Effects - Empties a list of markup variables.
  75  */
  76 void substitution_free(rb_dlink_list *varlist)
  77 {
  78         rb_dlink_node *nptr, *nptr2;
  79
  80         RB_DLINK_FOREACH_SAFE(nptr, nptr2, varlist->head)
  81         {
  82                 struct substitution_variable *tmp = (struct substitution_variable *) nptr->data;
  83
  84                 rb_dlinkDelete(nptr, varlist);
  85                 rb_free(tmp->name);
  86                 rb_free(tmp->value);
  87                 rb_free(tmp);
  88         }
  89 }
  90
  91 /*
  92  * substitution_parse
  93  *
  94  * Inputs       - A markup string, rb_dlink-list of markup values
  95  * Output       - A string which has been markup-replaced.
  96  * Side Effects - Strings larger than BUFSIZE are terminated.
  97  */
  98 char *substitution_parse(const char *fmt, rb_dlink_list *varlist)
  99 {
 100         static char buf[BUFSIZE];
 101         const char *ptr;
 102         char *bptr = buf;
 103
 104         for (ptr = fmt; *ptr != '\0' && bptr - buf < BUFSIZE; ptr++)
 105                 if (*ptr != '$')
 106                         *bptr++ = *ptr;
 107                 else if (*(ptr + 1) == '{')
 108                 {
 109                         static char varname[BUFSIZE];
 110                         char *vptr = varname;
 111                         const char *pptr;
 112                         rb_dlink_node *nptr;
 113
 114                         *vptr = '\0';
 115
 116                         /* break out ${var} */
 117                         for (pptr = ptr + 2; *pptr != '\0'; pptr++)
 118                         {
 119                                 if (*pptr != '}')
 120                                         *vptr++ = *pptr;
 121                                 else
 122                                 {
 123                                         *vptr++ = '\0';
 124                                         break;
 125                                 }
 126                         }
 127
 128                         s_assert(*varname != '\0');
 129                         s_assert(*pptr != '\0');
 130
 131                         /* advance ptr by length of variable */
 132                         ptr += (pptr - ptr);
 133
 134                         RB_DLINK_FOREACH(nptr, varlist->head)
 135                         {
 136                                 struct substitution_variable *val = (struct substitution_variable *) nptr->data;
 137
 138                                 if (!strcasecmp(varname, val->name))
 139                                 {
 140                                         rb_strlcpy(bptr, val->value, BUFSIZE - (bptr - buf));
 141                                         bptr += strlen(val->value);
 142                                         break;
 143                                 }
 144                         }
 145                 }
 146
 147         *bptr = '\0';
 148         return buf;
 149 }