intl/eval-plural.h

   1 /* Plural expression evaluation.
   2    Copyright (C) 2000-2019 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as published by
   6    the Free Software Foundation; either version 2.1 of the License, or
   7    (at your option) 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
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #ifndef STATIC
  18 #define STATIC static
  19 #endif
  20
  21 /* Evaluate the plural expression and return an index value.  */
  22 STATIC
  23 unsigned long int
  24 plural_eval (const struct expression *pexp, unsigned long int n)
  25 {
  26   switch (pexp->nargs)
  27     {
  28     case 0:
  29       switch (pexp->operation)
  30         {
  31         case var:
  32           return n;
  33         case num:
  34           return pexp->val.num;
  35         default:
  36           break;
  37         }
  38       /* NOTREACHED */
  39       break;
  40     case 1:
  41       {
  42         /* pexp->operation must be lnot.  */
  43         unsigned long int arg = plural_eval (pexp->val.args[0], n);
  44         return ! arg;
  45       }
  46     case 2:
  47       {
  48         unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
  49         if (pexp->operation == lor)
  50           return leftarg || plural_eval (pexp->val.args[1], n);
  51         else if (pexp->operation == land)
  52           return leftarg && plural_eval (pexp->val.args[1], n);
  53         else
  54           {
  55             unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
  56
  57             switch (pexp->operation)
  58               {
  59               case mult:
  60                 return leftarg * rightarg;
  61               case divide:
  62 #if !INTDIV0_RAISES_SIGFPE
  63                 if (rightarg == 0)
  64                   raise (SIGFPE);
  65 #endif
  66                 return leftarg / rightarg;
  67               case module:
  68 #if !INTDIV0_RAISES_SIGFPE
  69                 if (rightarg == 0)
  70                   raise (SIGFPE);
  71 #endif
  72                 return leftarg % rightarg;
  73               case plus:
  74                 return leftarg + rightarg;
  75               case minus:
  76                 return leftarg - rightarg;
  77               case less_than:
  78                 return leftarg < rightarg;
  79               case greater_than:
  80                 return leftarg > rightarg;
  81               case less_or_equal:
  82                 return leftarg <= rightarg;
  83               case greater_or_equal:
  84                 return leftarg >= rightarg;
  85               case equal:
  86                 return leftarg == rightarg;
  87               case not_equal:
  88                 return leftarg != rightarg;
  89               default:
  90                 break;
  91               }
  92           }
  93         /* NOTREACHED */
  94         break;
  95       }
  96     case 3:
  97       {
  98         /* pexp->operation must be qmop.  */
  99         unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
 100         return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
 101       }
 102     }
 103   /* NOTREACHED */
 104   return 0;
 105 }