Joe Buck writes:
> inline size_t __compute_size(size_t num, size_t size) {
> size_t product = num * size;
> return product >= num ? product : ~size_t(0);
> }
Florian Weimer writes:
>I don't think this check is correct. Consider num = 0x33333334 and
>size = 6. It seems that the check is difficult to perform efficiently
>unless the architecture provides unsigned multiplication with overflow
>detection, or an instruction to implement __builtin_clz.
This should work instead:
inline size_t __compute_size(size_t num, size_t size) {
if (num > ~size_t(0) / size)
return ~size_t(0);
return num * size;
}
Ross Ridge
