intl/plural-eval.c

   1 /* Plural expression evaluation.
   2    Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 static unsigned long int plural_eval (struct expression *pexp,
  21                                       unsigned long int n)
  22      internal_function;
  23
  24 static unsigned long int
  25 internal_function
  26 plural_eval (pexp, n)
  27      struct expression *pexp;
  28      unsigned long int n;
  29 {
  30   switch (pexp->nargs)
  31     {
  32     case 0:
  33       switch (pexp->operation)
  34         {
  35         case var:
  36           return n;
  37         case num:
  38           return pexp->val.num;
  39         default:
  40           break;
  41         }
  42       /* NOTREACHED */
  43       break;
  44     case 1:
  45       {
  46         /* pexp->operation must be lnot.  */
  47         unsigned long int arg = plural_eval (pexp->val.args[0], n);
  48         return ! arg;
  49       }
  50     case 2:
  51       {
  52         unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
  53         if (pexp->operation == lor)
  54           return leftarg || plural_eval (pexp->val.args[1], n);
  55         else if (pexp->operation == land)
  56           return leftarg && plural_eval (pexp->val.args[1], n);
  57         else
  58           {
  59             unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
  60
  61             switch (pexp->operation)
  62               {
  63               case mult:
  64                 return leftarg * rightarg;
  65               case divide:
  66                 return leftarg / rightarg;
  67               case module:
  68                 return leftarg % rightarg;
  69               case plus:
  70                 return leftarg + rightarg;
  71               case minus:
  72                 return leftarg - rightarg;
  73               case less_than:
  74                 return leftarg < rightarg;
  75               case greater_than:
  76                 return leftarg > rightarg;
  77               case less_or_equal:
  78                 return leftarg <= rightarg;
  79               case greater_or_equal:
  80                 return leftarg >= rightarg;
  81               case equal:
  82                 return leftarg == rightarg;
  83               case not_equal:
  84                 return leftarg != rightarg;
  85               default:
  86                 break;
  87               }
  88           }
  89         /* NOTREACHED */
  90         break;
  91       }
  92     case 3:
  93       {
  94         /* pexp->operation must be qmop.  */
  95         unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
  96         return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
  97       }
  98     }
  99   /* NOTREACHED */
 100   return 0;
 101 }