/* Expression parsing and evaluation for plural form selection.
   Copyright (C) 2000-2013 Free Software Foundation, Inc.
   Written by Ulrich Drepper <drepper@cygnus.com>, 2000.
   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, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _PLURAL_EXP_H
#define _PLURAL_EXP_H

#ifdef IN_LIBINTL
#include "gettextP.h"
#endif

#ifdef __cplusplus
extern "C" {
#endif


enum expression_operator
{
  /* Without arguments:  */
  var,				/* The variable "n".  */
  num,				/* Decimal number.  */
  /* Unary operators:  */
  lnot,				/* Logical NOT.  */
  /* Binary operators:  */
  mult,				/* Multiplication.  */
  divide,			/* Division.  */
  module,			/* Modulo operation.  */
  plus,				/* Addition.  */
  minus,			/* Subtraction.  */
  less_than,			/* Comparison.  */
  greater_than,			/* Comparison.  */
  less_or_equal,		/* Comparison.  */
  greater_or_equal,		/* Comparison.  */
  equal,			/* Comparison for equality.  */
  not_equal,			/* Comparison for inequality.  */
  land,				/* Logical AND.  */
  lor,				/* Logical OR.  */
  /* Ternary operators:  */
  qmop				/* Question mark operator.  */
};

/* This is the representation of the expressions to determine the
   plural form.  */
struct expression
{
  int nargs;			/* Number of arguments.  */
  enum expression_operator operation;
  struct
  {
    struct expression *args[3];	/* Up to three arguments.  */
    unsigned long int num;	/* Number value for `num'.  */
  } val;
};

/* This is the data structure to pass information to the parser and get
   the result in a thread-safe way.  */
struct parse_args
{
  const char *cp;
  struct expression *res;
};


/* Names for the libintl functions are a problem.  This source code is used
   1. in the GNU C Library library,
   2. in the GNU libintl library,
   3. in the GNU gettext tools.
   The function names in each situation must be different, to allow for
   binary incompatible changes in 'struct expression'.  Furthermore,
   1. in the GNU C Library library, the names have a __ prefix,
   2.+3. in the GNU libintl library and in the GNU gettext tools, the names
         must follow ANSI C and not start with __.
   So we have to distinguish the three cases.  */
#define FREE_EXPRESSION free_plural_expression
#define PLURAL_PARSE parse_plural_expression
#define GERMANIC_PLURAL germanic_plural
#define EXTRACT_PLURAL_EXPRESSION extract_plural_expression

extern void FREE_EXPRESSION (struct expression *exp);
extern int PLURAL_PARSE (void *arg);
extern const struct expression GERMANIC_PLURAL;
extern void EXTRACT_PLURAL_EXPRESSION(const char *nullentry, const struct expression **pluralp, unsigned long int *npluralsp);

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


#ifdef __cplusplus
}
#endif

#endif /* _PLURAL_EXP_H */
