89e5a32966
These functions add 2 or 3 longs, saturating to LONG_{MIN,MAX} instead
of overflowing.
Cc: Tobias Stoeckmann <tobias@stoeckmann.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
73 lines
1.1 KiB
C
73 lines
1.1 KiB
C
// SPDX-FileCopyrightText: 2023, Alejandro Colomar <alx@kernel.org>
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
|
|
|
|
|
#ifndef SHADOW_INCLUDE_LIB_ADDS_H_
|
|
#define SHADOW_INCLUDE_LIB_ADDS_H_
|
|
|
|
|
|
#include <config.h>
|
|
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "sizeof.h"
|
|
|
|
|
|
inline long addsl(long a, long b);
|
|
inline long addsl3(long a, long b, long c);
|
|
|
|
inline int cmpl(const void *p1, const void *p2);
|
|
|
|
|
|
inline long
|
|
addsl(long a, long b)
|
|
{
|
|
if (a > 0 && b > LONG_MAX - a) {
|
|
errno = EOVERFLOW;
|
|
return LONG_MAX;
|
|
}
|
|
if (a < 0 && b < LONG_MIN - a) {
|
|
errno = EOVERFLOW;
|
|
return LONG_MIN;
|
|
}
|
|
return a + b;
|
|
}
|
|
|
|
|
|
inline long
|
|
addsl3(long a, long b, long c)
|
|
{
|
|
int e;
|
|
long sum;
|
|
long n[3] = {a, b, c};
|
|
|
|
e = errno;
|
|
qsort(n, NITEMS(n), sizeof(n[0]), cmpl);
|
|
|
|
errno = 0;
|
|
sum = addsl(n[0], n[2]);
|
|
if (errno == EOVERFLOW)
|
|
return sum;
|
|
errno = e;
|
|
return addsl(sum, n[1]);
|
|
}
|
|
|
|
|
|
inline int
|
|
cmpl(const void *p1, const void *p2)
|
|
{
|
|
const long *l1 = p1;
|
|
const long *l2 = p2;
|
|
|
|
if (*l1 < *l2)
|
|
return -1;
|
|
if (*l1 > *l2)
|
|
return +1;
|
|
return 0;
|
|
}
|
|
|
|
|
|
#endif // include guard
|