From bbe35a6e1b54ef5cd7c1c471886c30ba85c0804e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 19:47:50 +0200 Subject: Adding upstream version 1.21. Signed-off-by: Daniel Baumann --- lib/xalloc-oversized.h | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 lib/xalloc-oversized.h (limited to 'lib/xalloc-oversized.h') diff --git a/lib/xalloc-oversized.h b/lib/xalloc-oversized.h new file mode 100644 index 0000000..7cd4a74 --- /dev/null +++ b/lib/xalloc-oversized.h @@ -0,0 +1,60 @@ +/* xalloc-oversized.h -- memory allocation size checking + + Copyright (C) 1990-2000, 2003-2004, 2006-2020 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 . */ + +#ifndef XALLOC_OVERSIZED_H_ +#define XALLOC_OVERSIZED_H_ + +#include +#include + +/* 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__ && !defined __clang__ +# 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_ */ -- cgit v1.2.3