1  /* mpz_realloc2 -- change allocated data size.
       2  
       3  Copyright 2001, 2002, 2008, 2015, 2021, 2022 Free Software Foundation,
       4  Inc.
       5  
       6  This file is part of the GNU MP Library.
       7  
       8  The GNU MP Library is free software; you can redistribute it and/or modify
       9  it under the terms of either:
      10  
      11    * the GNU Lesser General Public License as published by the Free
      12      Software Foundation; either version 3 of the License, or (at your
      13      option) any later version.
      14  
      15  or
      16  
      17    * the GNU General Public License as published by the Free Software
      18      Foundation; either version 2 of the License, or (at your option) any
      19      later version.
      20  
      21  or both in parallel, as here.
      22  
      23  The GNU MP Library is distributed in the hope that it will be useful, but
      24  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      25  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      26  for more details.
      27  
      28  You should have received copies of the GNU General Public License and the
      29  GNU Lesser General Public License along with the GNU MP Library.  If not,
      30  see https://www.gnu.org/licenses/.  */
      31  
      32  #include "gmp-impl.h"
      33  
      34  void
      35  mpz_realloc2 (mpz_ptr m, mp_bitcnt_t bits)
      36  {
      37    mp_size_t new_alloc;
      38  
      39    bits -= (bits != 0);		/* Round down, except if 0 */
      40    new_alloc = 1 + bits / GMP_NUMB_BITS;
      41  
      42    if (sizeof (unsigned long) > sizeof (int)) /* param vs _mp_size field */
      43      {
      44        if (UNLIKELY (new_alloc > INT_MAX))
      45  	MPZ_OVERFLOW;
      46      }
      47  
      48    if (ALLOC (m) == 0)
      49      {
      50        PTR (m) = __GMP_ALLOCATE_FUNC_LIMBS (new_alloc);
      51      }
      52    else
      53      {
      54        PTR (m) = __GMP_REALLOCATE_FUNC_LIMBS (PTR(m), ALLOC(m), new_alloc);
      55  
      56        /* Don't create an invalid number; if the current value doesn't fit after
      57  	 reallocation, clear it to 0.  */
      58        if (ABSIZ(m) > new_alloc)
      59  	SIZ(m) = 0;
      60      }
      61  
      62    ALLOC(m) = new_alloc;
      63  }