|
// FUNCTION TEMPLATE _Trim_matching_suffixes
|
|
template <class _FwdIt1, class _FwdIt2, class _Pr>
|
|
void _Trim_matching_suffixes(_FwdIt1&, _FwdIt2&, _Pr, forward_iterator_tag, forward_iterator_tag) {
|
|
// trim matching suffixes, forward iterators (do nothing)
|
|
}
|
|
|
|
template <class _FwdIt1, class _FwdIt2, class _Pr>
|
|
void _Trim_matching_suffixes(
|
|
_FwdIt1& _Last1, _FwdIt2& _Last2, _Pr _Pred, bidirectional_iterator_tag, bidirectional_iterator_tag) {
|
|
// trim matching suffixes, bidirectional iterators
|
|
// assumptions: same lengths, non-empty, !_Pred(*_First1, *_First2)
|
|
do { // find last inequality
|
|
--_Last1;
|
|
--_Last2;
|
|
} while (_Pred(*_Last1, *_Last2));
|
|
++_Last1;
|
|
++_Last2;
|
|
}
|
|
|
|
// FUNCTION TEMPLATE _Check_match_counts
|
|
template <class _FwdIt1, class _FwdIt2, class _Pr>
|
|
bool _Check_match_counts(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred) {
|
|
// test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred, same lengths
|
|
_Trim_matching_suffixes(_Last1, _Last2, _Pred, _Iter_cat_t<_FwdIt1>(), _Iter_cat_t<_FwdIt2>());
|
|
for (_FwdIt1 _Next1 = _First1; _Next1 != _Last1; ++_Next1) {
|
|
if (_Next1 == _Find_pr(_First1, _Next1, *_Next1, _Pred)) { // new value, compare match counts
|
|
_Iter_diff_t<_FwdIt2> _Count2 = _Count_pr(_First2, _Last2, *_Next1, _Pred);
|
|
if (_Count2 == 0) {
|
|
return false; // second range lacks value, fail
|
|
}
|
|
|
|
_FwdIt1 _Skip1 = _Next_iter(_Next1);
|
|
_Iter_diff_t<_FwdIt1> _Count1 = _Count_pr(_Skip1, _Last1, *_Next1, _Pred) + 1;
|
|
if (_Count2 != _Count1) {
|
|
return false; // match counts differ, fail
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// FUNCTION TEMPLATE is_permutation
|
|
template <class _FwdIt1, class _FwdIt2, class _Pr>
|
|
bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _Pr _Pred) {
|
|
// test if [_First1, _Last1) == permuted [_First2, ...), using _Pred
|
|
for (; _First1 != _Last1; ++_First1, (void) ++_First2) {
|
|
if (!_Pred(*_First1, *_First2)) {
|
|
// found first inequality, check match counts in suffix narrowing _Iter_diff_t<_FwdIt1> to
|
|
// _Iter_diff_t<_FwdIt2> is OK because if the 2nd range is shorter than the 1st, the user already
|
|
// triggered UB
|
|
auto _Last2 = _STD next(_First2, static_cast<_Iter_diff_t<_FwdIt2>>(_STD distance(_First1, _Last1)));
|
|
return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
template <class _FwdIt1, class _FwdIt2, class _Pr>
|
|
_NODISCARD bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _Pr _Pred) {
|