mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-23 10:34:07 +00:00
fa0a2b4e7c
This incorporates: 2017-01-09 maint: time stamp -> timestamp 2017-01-07 stdioext: Port to Minix 3.2 and newer 2017-01-06 glob, intprops, xalloc: work around Clang bug 2017-01-02 revert copyright-year change to synced files * doc/misc/texinfo.tex, lib/fpending.c, lib/intprops.h, lib/mktime.c: * lib/stat-time.h, lib/stdio-impl.h, lib/time.in.h, lib/timespec.h: * lib/utimens.c, lib/xalloc-oversized.h: Copy from gnulib.
61 lines
2.3 KiB
C
61 lines
2.3 KiB
C
/* xalloc-oversized.h -- memory allocation size checking
|
|
|
|
Copyright (C) 1990-2000, 2003-2004, 2006-2017 Free Software Foundation, Inc.
|
|
|
|
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 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
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
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, see <http://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef XALLOC_OVERSIZED_H_
|
|
#define XALLOC_OVERSIZED_H_
|
|
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
|
|
/* True if N * S would overflow in a size_t calculation,
|
|
or would generate a value larger than PTRDIFF_MAX.
|
|
This expands to a constant expression if N and S are both constants.
|
|
By gnulib convention, SIZE_MAX represents overflow in size
|
|
calculations, so the conservative size_t-based dividend to use here
|
|
is SIZE_MAX - 1. */
|
|
#define __xalloc_oversized(n, s) \
|
|
((size_t) (PTRDIFF_MAX < SIZE_MAX ? PTRDIFF_MAX : SIZE_MAX - 1) / (s) < (n))
|
|
|
|
#if PTRDIFF_MAX < SIZE_MAX
|
|
typedef ptrdiff_t __xalloc_count_type;
|
|
#else
|
|
typedef size_t __xalloc_count_type;
|
|
#endif
|
|
|
|
/* Return 1 if an array of N objects, each of size S, cannot exist
|
|
reliably due to size or ptrdiff_t arithmetic overflow. S must be
|
|
positive and N must be nonnegative. This is a macro, not a
|
|
function, so that it works correctly even when SIZE_MAX < N. */
|
|
|
|
#if 7 <= __GNUC__
|
|
# define xalloc_oversized(n, s) \
|
|
__builtin_mul_overflow_p (n, s, (__xalloc_count_type) 1)
|
|
#elif 5 <= __GNUC__ && !__STRICT_ANSI__
|
|
# define xalloc_oversized(n, s) \
|
|
(__builtin_constant_p (n) && __builtin_constant_p (s) \
|
|
? __xalloc_oversized (n, s) \
|
|
: ({ __xalloc_count_type __xalloc_count; \
|
|
__builtin_mul_overflow (n, s, &__xalloc_count); }))
|
|
|
|
/* Other compilers use integer division; this may be slower but is
|
|
more portable. */
|
|
#else
|
|
# define xalloc_oversized(n, s) __xalloc_oversized (n, s)
|
|
#endif
|
|
|
|
#endif /* !XALLOC_OVERSIZED_H_ */
|