1 /* -*- buffer-read-only: t -*- vi: set ro: */ 2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */ 3 /* xalloc-oversized.h -- memory allocation size checking 4 5 Copyright (C) 1990-2000, 2003-2004, 2006-2019 Free Software Foundation, Inc. 6 7 This program is free software: you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 19 20 #ifndef XALLOC_OVERSIZED_H_ 21 #define XALLOC_OVERSIZED_H_ 22 23 #include <stddef.h> 24 #include <stdint.h> 25 26 /* True if N * S would overflow in a size_t calculation, 27 or would generate a value larger than PTRDIFF_MAX. 28 This expands to a constant expression if N and S are both constants. 29 By gnulib convention, SIZE_MAX represents overflow in size 30 calculations, so the conservative size_t-based dividend to use here 31 is SIZE_MAX - 1. */ 32 #define __xalloc_oversized(n, s) \ 33 ((size_t) (PTRDIFF_MAX < SIZE_MAX ? PTRDIFF_MAX : SIZE_MAX - 1) / (s) < (n)) 34 35 #if PTRDIFF_MAX < SIZE_MAX 36 typedef ptrdiff_t __xalloc_count_type; 37 #else 38 typedef size_t __xalloc_count_type; 39 #endif 40 41 /* Return 1 if an array of N objects, each of size S, cannot exist 42 reliably due to size or ptrdiff_t arithmetic overflow. S must be 43 positive and N must be nonnegative. This is a macro, not a 44 function, so that it works correctly even when SIZE_MAX < N. */ 45 46 #if 7 <= __GNUC__ 47 # define xalloc_oversized(n, s) \ 48 __builtin_mul_overflow_p (n, s, (__xalloc_count_type) 1) 49 #elif 5 <= __GNUC__ && !defined __ICC && !__STRICT_ANSI__ 50 # define xalloc_oversized(n, s) \ 51 (__builtin_constant_p (n) && __builtin_constant_p (s) \ 52 ? __xalloc_oversized (n, s) \ 53 : ({ __xalloc_count_type __xalloc_count; \ 54 __builtin_mul_overflow (n, s, &__xalloc_count); })) 55 56 /* Other compilers use integer division; this may be slower but is 57 more portable. */ 58 #else 59 # define xalloc_oversized(n, s) __xalloc_oversized (n, s) 60 #endif 61 62 #endif /* !XALLOC_OVERSIZED_H_ */ 63