gmp-4.3.1/mpz/realloc2.c

/* mpz_realloc2 -- change allocated data size.

Copyright 2001, 2002, 2008 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 <stdlib.h>
#include <stdio.h>
#include "gmp.h"
#include "gmp-impl.h"

void
mpz_realloc2 (mpz_ptr m, unsigned long bits)
{
  mp_size_t new_alloc;

  bits -= (bits != 0);		/* Round down, except if 0 */
  new_alloc = 1 + bits / GMP_NUMB_BITS;

  if (sizeof (unsigned long) > sizeof (int)) /* param vs _mp_size field */
    {
      if (UNLIKELY (new_alloc > INT_MAX))
	{
	  fprintf (stderr, "gmp: overflow in mpz type\n");
	  abort ();
	}
    }

  PTR(m) = __GMP_REALLOCATE_FUNC_LIMBS (PTR(m), ALLOC(m), new_alloc);
  ALLOC(m) = new_alloc;

  /* Don't create an invalid number; if the current value doesn't fit after
     reallocation, clear it to 0.  */
  if (ABSIZ(m) > new_alloc)
    SIZ(m) = 0;
}