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Giac_maj/giac-1.4.9/intl/eval-plural.h 2.71 KB
6663b6c9   adorian   projet complet av...
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  /* Plural expression evaluation.
     Copyright (C) 2000-2003 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify it
     under the terms of the GNU Library General Public License as published
     by the Free Software Foundation; either version 2, or (at your option)
     any later version.
  
     This program 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
     Library General Public License for more details.
  
     You should have received a copy of the GNU Library General Public
     License along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
     USA.  */
  
  #ifndef STATIC
  #define STATIC static
  #endif
  
  /* Evaluate the plural expression and return an index value.  */
  STATIC
  unsigned long int
  internal_function
  plural_eval (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:
  #if !INTDIV0_RAISES_SIGFPE
  		if (rightarg == 0)
  		  raise (SIGFPE);
  #endif
  		return leftarg / rightarg;
  	      case module:
  #if !INTDIV0_RAISES_SIGFPE
  		if (rightarg == 0)
  		  raise (SIGFPE);
  #endif
  		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;
  }