intl/eval-plural.h

   1 /* Plural expression evaluation.
   2    Copyright (C) 2000-2002 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU Library General Public License as published
   6    by the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with this program; if not, write to the Free Software
  16    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17    USA.  */
  18
  19 #ifndef STATIC
  20 #define STATIC static
  21 #endif
  22
  23 /* Evaluate the plural expression and return an index value.  */
  24 STATIC unsigned long int plural_eval PARAMS ((struct expression *pexp,
  25                                               unsigned long int n))
  26      internal_function;
  27
  28 STATIC
  29 unsigned long int
  30 internal_function
  31 plural_eval (pexp, n)
  32      struct expression *pexp;
  33      unsigned long int n;
  34 {
  35   switch (pexp->nargs)
  36     {
  37     case 0:
  38       switch (pexp->operation)
  39         {
  40         case var:
  41           return n;
  42         case num:
  43           return pexp->val.num;
  44         default:
  45           break;
  46         }
  47       /* NOTREACHED */
  48       break;
  49     case 1:
  50       {
  51         /* pexp->operation must be lnot.  */
  52         unsigned long int arg = plural_eval (pexp->val.args[0], n);
  53         return ! arg;
  54       }
  55     case 2:
  56       {
  57         unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
  58         if (pexp->operation == lor)
  59           return leftarg || plural_eval (pexp->val.args[1], n);
  60         else if (pexp->operation == land)
  61           return leftarg && plural_eval (pexp->val.args[1], n);
  62         else
  63           {
  64             unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
  65
  66             switch (pexp->operation)
  67               {
  68               case mult:
  69                 return leftarg * rightarg;
  70               case divide:
  71 #if !INTDIV0_RAISES_SIGFPE
  72                 if (rightarg == 0)
  73                   raise (SIGFPE);
  74 #endif
  75                 return leftarg / rightarg;
  76               case module:
  77 #if !INTDIV0_RAISES_SIGFPE
  78                 if (rightarg == 0)
  79                   raise (SIGFPE);
  80 #endif
  81                 return leftarg % rightarg;
  82               case plus:
  83                 return leftarg + rightarg;
  84               case minus:
  85                 return leftarg - rightarg;
  86               case less_than:
  87                 return leftarg < rightarg;
  88               case greater_than:
  89                 return leftarg > rightarg;
  90               case less_or_equal:
  91                 return leftarg <= rightarg;
  92               case greater_or_equal:
  93                 return leftarg >= rightarg;
  94               case equal:
  95                 return leftarg == rightarg;
  96               case not_equal:
  97                 return leftarg != rightarg;
  98               default:
  99                 break;
 100               }
 101           }
 102         /* NOTREACHED */
 103         break;
 104       }
 105     case 3:
 106       {
 107         /* pexp->operation must be qmop.  */
 108         unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
 109         return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
 110       }
 111     }
 112   /* NOTREACHED */
 113   return 0;
 114 }