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Diffstat (limited to '')
| -rw-r--r-- | lib/adds.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/lib/adds.h b/lib/adds.h new file mode 100644 index 0000000..6544ce5 --- /dev/null +++ b/lib/adds.h @@ -0,0 +1,86 @@ +// 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 <stddef.h> +#include <stdlib.h> + +#include "sizeof.h" + + +#define addsl(a, b, ...) \ +({ \ + long addend_[] = {a, b, __VA_ARGS__}; \ + \ + addslN(NITEMS(addend_), addend_); \ +}) + + +inline long addsl2(long a, long b); +inline long addslN(size_t n, long addend[n]); + +inline int cmpl(const void *p1, const void *p2); + + +inline long +addsl2(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 +addslN(size_t n, long addend[n]) +{ + int e; + + if (n == 0) { + errno = EDOM; + return 0; + } + + e = errno; + while (n > 1) { + qsort(addend, n, sizeof(addend[0]), cmpl); + + errno = 0; + addend[0] = addsl2(addend[0], addend[--n]); + if (errno == EOVERFLOW) + return addend[0]; + } + errno = e; + return addend[0]; +} + + +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 |