[libcxx-commits] [PATCH] D61771: Comparing Unordered Containers (P0809)

[Zoe Carver via Phabricator via libcxx-commits]

zoecarver marked an inline comment as done.
zoecarver added inline comments.


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Comment at: include/unordered_map:2274
         return false;
-    typedef typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator
-                                                                 const_iterator;
-    typedef pair<const_iterator, const_iterator> _EqRng;
-    for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;)
-    {
-        _EqRng __xeq = __x.equal_range(__i->first);
-        _EqRng __yeq = __y.equal_range(__i->first);
-        if (_VSTD::distance(__xeq.first, __xeq.second) !=
-            _VSTD::distance(__yeq.first, __yeq.second) ||
-                  !_VSTD::is_permutation(__xeq.first, __xeq.second, __yeq.first))
-            return false;
-        __i = __xeq.second;
-    }
-    return true;
+    return _VSTD::is_permutation(__x.begin(), __x.end(), __y.begin());
 }
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>From my tests, simply using `is_permutation` here is quite a bit faster than the previous method of comparison. I think that both bits of code are functionally equivalent (but let me know if that is not the case).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D61771/new/

https://reviews.llvm.org/D61771