This makes to_string approximately twice as fast at any optimization
level. Instead of iterating through every bit, jump straight to the next
bit that is set, by using _Find_first and _Find_next.
libstdc++-v3/ChangeLog:
* include/std/bitset (bitset::_M_copy_to_string): Find set bits
instead of iterating over individual bits.
_CharT __zero, _CharT __one) const
{
__s.assign(_Nb, __zero);
- for (size_t __i = _Nb; __i > 0; --__i)
- if (_Unchecked_test(__i - 1))
- _Traits::assign(__s[_Nb - __i], __one);
+ size_t __n = this->_Find_first();
+ while (__n < _Nb)
+ {
+ __s[_Nb - __n - 1] = __one;
+ __n = _Find_next(__n);
+ }
}
#endif // HOSTED