/* mpq expression evaluation

Copyright 2000, 2001, 2002 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 2.1 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; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */

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


/* Change this to "#define TRACE(x) x" to get some traces. */
#define TRACE(x)


static void
e_mpq_pow_ui (mpq_ptr r, mpq_srcptr b, unsigned long e)
{
  mpz_pow_ui (mpq_numref(r), mpq_numref(b), e);
  mpz_pow_ui (mpq_denref(r), mpq_denref(b), e);
}

/* Wrapped because mpq_sgn is a macro. */
static int
e_mpq_sgn (mpq_srcptr x)
{
  return mpq_sgn (x);
}

/* Wrapped because mpq_equal only guarantees a non-zero return, whereas we
   want 1 or 0 for == and !=. */
static int
e_mpq_equal (mpq_srcptr x, mpq_srcptr y)
{
  return mpq_equal (x, y) != 0;
}
static int
e_mpq_notequal (mpq_srcptr x, mpq_srcptr y)
{
  return ! mpq_equal (x, y);
}

static void
e_mpq_num (mpq_ptr w, mpq_srcptr x)
{
  if (w != x)
    mpz_set (mpq_numref(w), mpq_numref(x));
  mpz_set_ui (mpq_denref(w), 1L);
}
static void
e_mpq_den (mpq_ptr w, mpq_srcptr x)
{
  if (w == x)
    mpz_swap (mpq_numref(w), mpq_denref(w));
  else
    mpz_set (mpq_numref(w), mpq_denref(x));
  mpz_set_ui (mpq_denref(w), 1L);
}


static __gmp_const struct mpexpr_operator_t  _mpq_expr_standard_table[] = {

  { "**",  (mpexpr_fun_t) e_mpq_pow_ui,
    MPEXPR_TYPE_BINARY_UI | MPEXPR_TYPE_RIGHTASSOC,                   220 },
  
  { "!",   (mpexpr_fun_t) e_mpq_sgn,
    MPEXPR_TYPE_LOGICAL_NOT | MPEXPR_TYPE_PREFIX,                     210 },
  { "-",   (mpexpr_fun_t) mpq_neg,
    MPEXPR_TYPE_UNARY | MPEXPR_TYPE_PREFIX,                           210 },

  { "*",   (mpexpr_fun_t) mpq_mul,           MPEXPR_TYPE_BINARY,      200 },
  { "/",   (mpexpr_fun_t) mpq_div,           MPEXPR_TYPE_BINARY,      200 },

  { "+",   (mpexpr_fun_t) mpq_add,           MPEXPR_TYPE_BINARY,      190 },
  { "-",   (mpexpr_fun_t) mpq_sub,           MPEXPR_TYPE_BINARY,      190 },

  { "<<",  (mpexpr_fun_t) mpq_mul_2exp,      MPEXPR_TYPE_BINARY_UI,   180 },
  { ">>",  (mpexpr_fun_t) mpq_div_2exp,      MPEXPR_TYPE_BINARY_UI,   180 },

  { "<=",  (mpexpr_fun_t) mpq_cmp,           MPEXPR_TYPE_CMP_LE,      170 },
  { "<",   (mpexpr_fun_t) mpq_cmp,           MPEXPR_TYPE_CMP_LT,      170 },
  { ">=",  (mpexpr_fun_t) mpq_cmp,           MPEXPR_TYPE_CMP_GE,      170 },
  { ">",   (mpexpr_fun_t) mpq_cmp,           MPEXPR_TYPE_CMP_GT,      170 },

  { "==",  (mpexpr_fun_t) e_mpq_equal,       MPEXPR_TYPE_I_BINARY,    160 },
  { "!=",  (mpexpr_fun_t) e_mpq_notequal,    MPEXPR_TYPE_I_BINARY,    160 },

  { "&&",  (mpexpr_fun_t) e_mpq_sgn,         MPEXPR_TYPE_LOGICAL_AND, 120 },
  { "||",  (mpexpr_fun_t) e_mpq_sgn,         MPEXPR_TYPE_LOGICAL_OR,  110 },

  { ":",   NULL,                             MPEXPR_TYPE_COLON,       101 },
  { "?",   (mpexpr_fun_t) e_mpq_sgn,         MPEXPR_TYPE_QUESTION,    100 },

  { ")",   (mpexpr_fun_t) e_mpq_sgn,         MPEXPR_TYPE_CLOSEPAREN,    4 },
  { "(",   (mpexpr_fun_t) e_mpq_sgn,         MPEXPR_TYPE_OPENPAREN,     3 },
  { ",",   (mpexpr_fun_t) e_mpq_sgn,         MPEXPR_TYPE_ARGSEP,        2 },
  { "$",   NULL,                             MPEXPR_TYPE_VARIABLE,      1 },

  { "abs",  (mpexpr_fun_t) mpq_abs,          MPEXPR_TYPE_UNARY            },
  { "cmp",  (mpexpr_fun_t) mpq_cmp,          MPEXPR_TYPE_I_BINARY         },
  { "den",  (mpexpr_fun_t) e_mpq_den,        MPEXPR_TYPE_UNARY            },
  { "max",  (mpexpr_fun_t) mpq_cmp,  MPEXPR_TYPE_MAX | MPEXPR_TYPE_PAIRWISE },
  { "min",  (mpexpr_fun_t) mpq_cmp,  MPEXPR_TYPE_MIN | MPEXPR_TYPE_PAIRWISE },
  { "num",  (mpexpr_fun_t) e_mpq_num,        MPEXPR_TYPE_UNARY            },
  { "sgn",  (mpexpr_fun_t) e_mpq_sgn,        MPEXPR_TYPE_I_UNARY          },

  { NULL }
};

__gmp_const struct mpexpr_operator_t * __gmp_const mpq_expr_standard_table
= _mpq_expr_standard_table;


int
#if HAVE_STDARG
mpq_expr (mpq_ptr res, int base, __gmp_const char *e, ...)
#else
mpq_expr (va_alist)
     va_dcl
#endif
{
  mpq_srcptr  var[MPEXPR_VARIABLES];
  va_list     ap;
  int         ret;
#if HAVE_STDARG
  va_start (ap, e);
#else
  mpq_ptr           res;
  int               base;
  __gmp_const char  *e;
  va_start (ap);
  res  = va_arg (ap, mpq_ptr);
  base = va_arg (ap, int);
  e    = va_arg (ap, __gmp_const char *);
#endif

  TRACE (printf ("mpq_expr(): base %d, %s\n", base, e));
  ret = mpexpr_va_to_var ((void **) var, ap);
  va_end (ap);

  if (ret != MPEXPR_RESULT_OK)
    return ret;

  return mpq_expr_a (mpq_expr_standard_table, res, base, e, strlen(e), var);
}