spot/lib/xalloc-oversized.h
Alexandre Duret-Lutz 80d50c5665 gnulib: upgrade to today's version
* tools/snippet/_Noreturn.h, tools/snippet/c++defs.h,
tools/snippet/arg-nonnull.h, tools/snippet/warn-on-use.h: Rename to...
* lib/_Noreturn.h, lib/c++defs.h, lib/arg-nonnull.h,
lib/warn-on-use.h: ... these.
* lib/filename.h, lib/getopt-cdefs.in.h, lib/getopt-core.h,
lib/getopt-ext.h, lib/getopt-pfx-core.h, lib/getopt-pfx-ext.h,
lib/localtime-buffer.c, lib/localtime-buffer.h, lib/malloca.c,
lib/malloca.h, lib/malloca.valgrind, lib/stat-w32.c, lib/stat-w32.h,
m4/eealloc.m4, m4/localtime-buffer.m4, m4/malloca.m4: New files.
* lib/argp-help.c, lib/argp-parse.c, lib/error.c, lib/float.in.h,
lib/getopt1.c, lib/getopt.c, lib/getopt.in.h, lib/getopt_int.h,
lib/gettext.h, lib/gettimeofday.c, lib/intprops.h, lib/isatty.c,
lib/limits.in.h, lib/localcharset.c, lib/Makefile.am, lib/mbrtowc.c,
lib/mbsinit.c, lib/msvc-nothrow.c, lib/quotearg.c, lib/stat.c,
lib/stdalign.in.h, lib/stdint.in.h, lib/string.in.h,
lib/sys_stat.in.h, lib/sys_types.in.h, lib/tempname.c, lib/time.in.h,
lib/unistd.in.h, lib/vasnprintf.c, lib/wchar.in.h, lib/wctype.in.h,
lib/xalloc.h, lib/xalloc-oversized.h, m4/fcntl-o.m4, m4/float_h.m4,
m4/getopt.m4, m4/gettimeofday.m4, m4/gnulib-common.m4,
m4/gnulib-comp.m4, m4/include_next.m4, m4/largefile.m4, m4/lstat.m4,
m4/mbrtowc.m4, m4/memchr.m4, m4/mkstemp.m4, m4/printf.m4, m4/sleep.m4,
m4/stat.m4, m4/stdalign.m4, m4/stdint.m4, m4/strerror.m4,
m4/string_h.m4, m4/sys_stat_h.m4, m4/sys_time_h.m4, m4/sys_types_h.m4,
m4/time_h.m4, m4/unistd_h.m4, m4/wchar_h.m4, m4/wctype_h.m4,
m4/wint_t.m4: Update.
2017-08-08 15:00:11 +02:00

60 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__ && !defined __ICC && !__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_ */