source: vendor/glibc/current/intl/plural-eval.c

/* Plural expression evaluation.
   Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

static unsigned long int plural_eval (struct expression *pexp,
                                      unsigned long int n)
     internal_function;

static unsigned long int
internal_function
plural_eval (pexp, n)
     struct expression *pexp;
     unsigned long int n;
{
  switch (pexp->nargs)
    {
    case 0:
      switch (pexp->operation)
        {
        case var:
          return n;
        case num:
          return pexp->val.num;
        default:
          break;
        }
      /* NOTREACHED */
      break;
    case 1:
      {
        /* pexp->operation must be lnot.  */
        unsigned long int arg = plural_eval (pexp->val.args[0], n);
        return ! arg;
      }
    case 2:
      {
        unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
        if (pexp->operation == lor)
          return leftarg || plural_eval (pexp->val.args[1], n);
        else if (pexp->operation == land)
          return leftarg && plural_eval (pexp->val.args[1], n);
        else
          {
            unsigned long int rightarg = plural_eval (pexp->val.args[1], n);

            switch (pexp->operation)
              {
              case mult:
                return leftarg * rightarg;
              case divide:
                return leftarg / rightarg;
              case module:
                return leftarg % rightarg;
              case plus:
                return leftarg + rightarg;
              case minus:
                return leftarg - rightarg;
              case less_than:
                return leftarg < rightarg;
              case greater_than:
                return leftarg > rightarg;
              case less_or_equal:
                return leftarg <= rightarg;
              case greater_or_equal:
                return leftarg >= rightarg;
              case equal:
                return leftarg == rightarg;
              case not_equal:
                return leftarg != rightarg;
              default:
                break;
              }
          }
        /* NOTREACHED */
        break;
      }
    case 3:
      {
        /* pexp->operation must be qmop.  */
        unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
        return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
      }
    }
  /* NOTREACHED */
  return 0;
}