/* mpq expression evaluation

Copyright 2000, 2001, 2004 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP 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 3 of the License, or (at your
option) any later version.

The GNU MP 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 MP Library.  If not, see http://www.gnu.org/licenses/.  */


#include <stdio.h>
#include "gmp.h"
#include "expr-impl.h"


static int
e_mpq_ulong_p (mpq_srcptr q)
{
  return mpz_fits_ulong_p (mpq_numref (q))
    && mpz_cmp_ui (mpq_denref (q), 1L) == 0;
}

/* get value as a ui, on the assumption it fits */
static int
e_mpq_get_ui_fits (mpq_srcptr q)
{
  return mpz_get_ui (mpq_numref (q));
}

static void
e_mpq_set_si1 (mpq_ptr q, long num)
{
  mpq_set_si (q, num, 1L);
}

/* The same as mpz, but putting the result in the numerator.  Negatives and
   fractions aren't parsed here because '-' and '/' are operators. */
static size_t
e_mpq_number (mpq_ptr res, const char *e, size_t elen, int base)
{
  mpz_set_ui (mpq_denref (res), 1L);
  return mpexpr_mpz_number (mpq_numref (res), e, elen, base);
}


/* ignoring prec */
static void
e_mpq_init (mpq_ptr q, unsigned long prec)
{
  mpq_init (q);
}

int
mpq_expr_a (const struct mpexpr_operator_t *table,
            mpq_ptr res, int base,
            const char *e, size_t elen,
            mpq_srcptr var[26])
{
  struct mpexpr_parse_t  p;

  p.table = table;
  p.res = (mpX_ptr) res;
  p.base = base;
  p.e = e;
  p.elen = elen;
  p.var = (mpX_srcptr *) var;

  p.mpX_clear       = (mpexpr_fun_one_t)      mpq_clear;
  p.mpX_ulong_p     = (mpexpr_fun_i_unary_t)  e_mpq_ulong_p;
  p.mpX_get_ui      = (mpexpr_fun_get_ui_t)   e_mpq_get_ui_fits;
  p.mpX_init        = (mpexpr_fun_unary_ui_t) e_mpq_init;
  p.mpX_number      = (mpexpr_fun_number_t)   e_mpq_number;
  p.mpX_set         = (mpexpr_fun_unary_t)    mpq_set;
  p.mpX_set_or_swap = (mpexpr_fun_unary_t)    mpq_swap;
  p.mpX_set_si      = (mpexpr_fun_set_si_t)   e_mpq_set_si1;
  p.mpX_swap        = (mpexpr_fun_swap_t)     mpq_swap;

  return mpexpr_evaluate (&p);
}