/* xalloc.h -- malloc with out-of-memory checking
Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2003, 2004, 2006 Free Software Foundation, Inc.
+ 1999, 2000, 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef XALLOC_H_
# define XALLOC_H_
allocating an initial block with a nonzero size, or by allocating a
larger block.
- In the following implementation, nonzero sizes are doubled so that
- repeated reallocations have O(N log N) overall cost rather than
- O(N**2) cost, but the specification for this function does not
- guarantee that sizes are doubled.
+ In the following implementation, nonzero sizes are increased by a
+ factor of approximately 1.5 so that repeated reallocations have
+ O(N) overall cost rather than O(N**2) cost, but the
+ specification for this function does not guarantee that rate.
Here is an example of use:
}
else
{
- if (((size_t) -1) / 2 / s < n)
+ /* Set N = ceil (1.5 * N) so that progress is made if N == 1.
+ Check for overflow, so that N * S stays in size_t range.
+ The check is slightly conservative, but an exact check isn't
+ worth the trouble. */
+ if ((size_t) -1 / 3 * 2 / s <= n)
xalloc_die ();
- n *= 2;
+ n += (n + 1) / 2;
}
*pn = n;