utility/capability.c

   1 /**********************************************************************
   2  Freeciv - Copyright (C) 1996 - A Kjeldberg, L Gregersen, P Unold
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; either version 2, or (at your option)
   6    any later version.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12 ***********************************************************************/
  13
  14 #ifdef HAVE_CONFIG_H
  15 #include <fc_config.h>
  16 #endif
  17
  18 #include "fc_prehdrs.h"
  19
  20 #include <string.h>
  21
  22 /* utility */
  23 #include "shared.h"             /* TRUE, FALSE */
  24 #include "support.h"            /* fc_is* */
  25
  26 #include "capability.h"
  27
  28 #define GET_TOKEN(start, end)                                               \
  29   {                                                                         \
  30     /* skip leading whitespace */                                           \
  31     while (fc_isspace(*start)) {                                            \
  32       start++;                                                              \
  33     }                                                                       \
  34     /* skip to end of token */                                              \
  35     for (end = start; *end != '\0' && !fc_isspace(*end) && *end != ',';     \
  36          end++) {                                                           \
  37       /* nothing */                                                         \
  38     }                                                                       \
  39   }
  40
  41 /***************************************************************************
  42   This routine returns true if the capability in cap appears
  43   in the capability list in capstr.  The capabilities in capstr
  44   are allowed to start with a "+", but the capability in cap must not.
  45 ***************************************************************************/
  46 static bool fc_has_capability(const char *cap, const char *capstr,
  47                               const size_t cap_len)
  48 {
  49   const char *next;
  50
  51   fc_assert_ret_val(capstr != NULL, FALSE);
  52
  53   for (;;) {
  54     GET_TOKEN(capstr, next);
  55
  56     if (*capstr == '+') {
  57       capstr++;
  58     }
  59     if ((next-capstr == cap_len) && strncmp(cap, capstr, cap_len)==0) {
  60       return TRUE;
  61     }
  62     if (*next == '\0') {
  63       return FALSE;
  64     }
  65
  66     capstr = next+1;
  67   }
  68 }
  69
  70 /***************************************************************************
  71   Wrapper for fc_has_capability() for NULL terminated strings.
  72 ***************************************************************************/
  73 bool has_capability(const char *cap, const char *capstr)
  74 {
  75   return fc_has_capability(cap, capstr, strlen(cap));
  76 }
  77
  78 /***************************************************************************
  79   This routine returns true if all the mandatory capabilities in
  80   us appear in them.
  81 ***************************************************************************/
  82 bool has_capabilities(const char *us, const char *them)
  83 {
  84   const char *next;
  85
  86   for (;;) {
  87     GET_TOKEN(us, next);
  88
  89     if (*us == '+' && !fc_has_capability(us+1, them, next-(us+1))) {
  90       return FALSE;
  91     }
  92     if (*next == '\0') {
  93       return TRUE;
  94     }
  95
  96     us = next+1;
  97   }
  98 }