PIPS
|
#include <stddef.h>
#include <limits.h>
Go to the source code of this file.
Macros | |
#define | XSIZE_INLINE _GL_INLINE |
xsize.h – Checked size_t computations. More... | |
#define | xcast_size_t(N) ((N) <= SIZE_MAX ? (size_t) (N) : SIZE_MAX) |
The size of memory objects is often computed through expressions of type size_t. More... | |
#define | xtimes(N, ELSIZE) ((N) <= SIZE_MAX / (ELSIZE) ? (size_t) (N) * (ELSIZE) : SIZE_MAX) |
Multiplication of a count with an element size, with overflow check. More... | |
#define | size_overflow_p(SIZE) ((SIZE) == SIZE_MAX) |
Check for overflow. More... | |
#define | size_in_bounds_p(SIZE) ((SIZE) != SIZE_MAX) |
Check against overflow. More... | |
Functions | |
XSIZE_INLINE size_t | xsum (size_t size1, size_t size2) |
Sum of two sizes, with overflow check. More... | |
XSIZE_INLINE size_t | xsum3 (size_t size1, size_t size2, size_t size3) |
Sum of three sizes, with overflow check. More... | |
XSIZE_INLINE size_t | xsum4 (size_t size1, size_t size2, size_t size3, size_t size4) |
Sum of four sizes, with overflow check. More... | |
XSIZE_INLINE size_t | xmax (size_t size1, size_t size2) |
Maximum of two sizes, with overflow check. More... | |
The size of memory objects is often computed through expressions of type size_t.
Example: void* p = malloc (header_size + n * element_size). These computations can lead to overflow. When this happens, malloc() returns a piece of memory that is way too small, and the program then crashes while attempting to fill the memory. To avoid this, the functions and macros in this file check for overflow. The convention is that SIZE_MAX represents overflow. malloc (SIZE_MAX) is not guaranteed to fail – think of a malloc implementation that uses mmap –, it's recommended to use size_overflow_p() or size_in_bounds_p() before invoking malloc(). The example thus becomes: size_t size = xsum (header_size, xtimes (n, element_size)); void *p = (size_in_bounds_p (size) ? malloc (size) : NULL); Convert an arbitrary value >= 0 to type size_t.
#define XSIZE_INLINE _GL_INLINE |
xsize.h – Checked size_t computations.
Copyright (C) 2003, 2008-2014 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, 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/.
Get size_t.
Get SIZE_MAX.
XSIZE_INLINE size_t xmax | ( | size_t | size1, |
size_t | size2 | ||
) |
Maximum of two sizes, with overflow check.
No explicit check is needed here, because for any n: max (SIZE_MAX, n) == SIZE_MAX and max (n, SIZE_MAX) == SIZE_MAX.
Definition at line 94 of file xsize.h.
Referenced by VASNPRINTF().
XSIZE_INLINE size_t xsum | ( | size_t | size1, |
size_t | size2 | ||
) |
Sum of two sizes, with overflow check.
Definition at line 63 of file xsize.h.
References SIZE_MAX, and sum().
Referenced by MAX_ROOM_NEEDED(), PRINTF_PARSE(), VASNPRINTF(), xsum3(), and xsum4().
XSIZE_INLINE size_t xsum3 | ( | size_t | size1, |
size_t | size2, | ||
size_t | size3 | ||
) |
Sum of three sizes, with overflow check.
Definition at line 74 of file xsize.h.
References xsum().
Referenced by VASNPRINTF().