dnl A function to check for the existence and usability of GMP.
dnl Copyright (C) 2001-2004 Roberto Bagnara <bagnara@cs.unipr.it>
dnl
dnl This file is part of the Parma Polyhedra Library (PPL).
dnl
dnl The PPL is free software; you can redistribute it and/or modify it
dnl under the terms of the GNU General Public License as published by the
dnl Free Software Foundation; either version 2 of the License, or (at your
dnl option) any later version.
dnl
dnl The PPL is distributed in the hope that it will be useful, but WITHOUT
dnl ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
dnl FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
dnl for more details.
dnl
dnl You should have received a copy of the GNU General Public License
dnl along with this program; if not, write to the Free Software
dnl Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
dnl USA.
dnl
dnl For the most up-to-date information see the Parma Polyhedra Library
dnl site: http://www.cs.unipr.it/ppl/ .
dnl
AC_DEFUN([AC_CHECK_GMP],
[
dnl Since libgmp and libgmpxx are usually installed in the same location,
dnl let the prefixes default from each other.
if test -n "$with_libgmpxx_prefix" && test -z "$with_libgmp_prefix"; then
  with_libgmp_prefix="$with_libgmpxx_prefix"
else
  if test -n "$with_libgmp_prefix" && test -z "$with_libgmpxx_prefix"; then
    with_libgmpxx_prefix="$with_libgmp_prefix"
  fi
fi

dnl Check how to link with libgmp.
AC_LIB_LINKFLAGS([gmp])

dnl Check how to link with libgmpxx.
AC_LIB_LINKFLAGS([gmpxx], [gmp])

ac_save_LIBS="$LIBS"
LIBS="$LIBS $LIBGMPXX"
AC_LANG_PUSH(C++)

AC_MSG_CHECKING([for the GMP library])
AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <gmpxx.h>

using namespace std;

int main() {
  mpz_class n("3141592653589793238462643383279502884");
  exit(0);
}
]])],
  AC_MSG_RESULT(yes)
  ac_cv_have_gmp=yes,
  AC_MSG_RESULT(no)
  ac_cv_have_gmp=no,
  AC_MSG_RESULT(no)
  ac_cv_have_gmp=no)

have_gmp=${ac_cv_have_gmp}

if test x"$ac_cv_have_gmp" = xyes
then

AC_MSG_CHECKING([size of GMP mp_limb_t])
ac_cv_sizeof_mp_limb_t=none
for size in 2 4 8
do
  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
#include <gmp.h>

int main() {
  switch (0) {
  case 0:
  case (sizeof(mp_limb_t) == $size):
    ;
  }
  return 0;
}
]])],
    ac_cv_sizeof_mp_limb_t=$size; break)
done
AC_MSG_RESULT($size)
AC_DEFINE_UNQUOTED(SIZEOF_MP_LIMB_T, $size,
  [Size of GMP's mp_limb_t.])

AC_MSG_CHECKING([whether GMP has been compiled with support for exceptions])
AC_RUN_IFELSE([AC_LANG_SOURCE([[
#include <gmpxx.h>
#include <new>
#include <cstddef>
#include <cstdlib>

using namespace std;

static void*
x_malloc(size_t) {
  throw bad_alloc();
}

static void*
x_realloc(void*, size_t, size_t) {
  throw bad_alloc();
}

static void
x_free(void*, size_t) {
}

int main() {
  mp_set_memory_functions(x_malloc, x_realloc, x_free);
  try {
    mpz_class n("3141592653589793238462643383279502884");
  }
  catch (bad_alloc) {
    exit(0);
  }
  exit(1);
}
]])],
  AC_MSG_RESULT(yes)
  ac_cv_gmp_supports_exceptions=yes,
  AC_MSG_RESULT(no)
  ac_cv_gmp_supports_exceptions=no,
  AC_MSG_RESULT(no)
  ac_cv_gmp_supports_exceptions=no)

gmp_supports_exceptions=${ac_cv_gmp_supports_exceptions}
if test x"$gmp_supports_exceptions" = xyes
then
  value=1
else
  value=0
fi
AC_DEFINE_UNQUOTED(GMP_SUPPORTS_EXCEPTIONS, $value,
  [Not zero if GMP has been compiled with support for exceptions.])

fi

AC_LANG_POP(C++)
LIBS="$ac_save_LIBS"

dnl We use libtool, therefore we take $LTLIBGMPXX, not $LIBGMPXX.
gmp_library_option="$LTLIBGMPXX"
])