diff options
Diffstat (limited to 'gl/xalloc.h')
| -rw-r--r-- | gl/xalloc.h | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/gl/xalloc.h b/gl/xalloc.h index 17ab5142..40dcf4bd 100644 --- a/gl/xalloc.h +++ b/gl/xalloc.h @@ -1,12 +1,12 @@ /* 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, 2008 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 @@ -14,8 +14,7 @@ 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_ @@ -29,7 +28,7 @@ extern "C" { # ifndef __attribute__ -# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__ +# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) # define __attribute__(x) # endif # endif @@ -139,10 +138,10 @@ xnrealloc (void *p, size_t n, size_t s) 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: @@ -204,9 +203,13 @@ x2nrealloc (void *p, size_t *pn, size_t s) } 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; |