init2.c revision 1.1.1.1 
1/* mpz_init2 -- initialize mpz, with requested size in bits.
2
3Copyright 2001, 2002, 2008 Free Software Foundation, Inc.
4
5This file is part of the GNU MP Library.
6
7The GNU MP Library is free software; you can redistribute it and/or modify
8it under the terms of the GNU Lesser General Public License as published by
9the Free Software Foundation; either version 3 of the License, or (at your
10option) any later version.
11
12The GNU MP Library is distributed in the hope that it will be useful, but
13WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
15License for more details.
16
17You should have received a copy of the GNU Lesser General Public License
18along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
19
20#include <stdlib.h>
21#include <stdio.h>
22#include "gmp.h"
23#include "gmp-impl.h"
24
25void
26mpz_init2 (mpz_ptr x, mp_bitcnt_t bits)
27{
28  mp_size_t  new_alloc;
29
30  bits -= (bits != 0);		/* Round down, except if 0 */
31  new_alloc = 1 + bits / GMP_NUMB_BITS;
32
33  if (sizeof (unsigned long) > sizeof (int)) /* param vs _mp_size field */
34    {
35      if (UNLIKELY (new_alloc > INT_MAX))
36	{
37	  fprintf (stderr, "gmp: overflow in mpz type\n");
38	  abort ();
39	}
40    }
41
42  PTR(x) = __GMP_ALLOCATE_FUNC_LIMBS (new_alloc);
43  ALLOC(x) = new_alloc;
44  SIZ(x) = 0;
45
46#ifdef __CHECKER__
47  /* let the low limb look initialized, for the benefit of mpz_get_ui etc */
48  PTR(x)[0] = 0;
49#endif
50}
51