core-lightning/common/overflows.h
practicalswift 8df29d169c The overflow check mul_overflows_s64(int64_t, int64_t) overflows and triggers UB :-) Remove it
The overflow check `mul_overflows_s64(int64_t, int64_t)` overflows.
Since this is an signed integer overflow this triggers UB, which
in turn means that we cannot trust the check.

Luckily mul_overflows_s64(int64_t, int64_t) is unused. Removing it.
2018-03-27 23:18:48 +00:00

25 lines
506 B
C

#ifndef LIGHTNING_COMMON_OVERFLOWS_H
#define LIGHTNING_COMMON_OVERFLOWS_H
#include "config.h"
static inline bool add_overflows_size_t(uint64_t a, uint64_t b)
{
return (size_t)a != a || (size_t)b != b || (a + b) < (size_t)a;
}
static inline bool add_overflows_u64(uint64_t a, uint64_t b)
{
return (a + b) < a;
}
static inline bool mul_overflows_u64(uint64_t a, uint64_t b)
{
uint64_t ret;
if (a == 0)
return false;
ret = a * b;
return (ret / a != b);
}
#endif /* LIGHTNING_COMMON_OVERFLOWS_H */