Fix the BinaryPredicate form of std::is_permutation to not rely on operator==

According to [1], forms 2 and 4 of std::is_permutation should use the passed in
binary predicate to compare elements. operator== should only be used for forms
1 and 3 which do not take a binary predicate.

This CL fixes forms 2 and 4 which relied on operator== for some comparisons.

[1] http://en.cppreference.com/w/cpp/algorithm/is_permutation

Patch by Thomas Anderson!

Differential Revision: https://reviews.llvm.org/D42518

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@323563 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Peter Collingbourne
2018-01-26 21:23:27 +00:00
parent 44aacb7850
commit 27c341db41
2 changed files with 34 additions and 2 deletions

View File

@@ -1418,7 +1418,11 @@ is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
{
// Have we already counted the number of *__i in [f1, l1)?
if (find(__first1, __i, *__i) == __i) {
_ForwardIterator1 __match = __first1;
for (; __match != __i; ++__match)
if (__pred(*__match, *__i))
break;
if (__match == __i) {
// Count number of *__i in [f2, l2)
_D1 __c2 = 0;
for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
@@ -1479,7 +1483,11 @@ __is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
{
// Have we already counted the number of *__i in [f1, l1)?
if (find(__first1, __i, *__i) == __i) {
_ForwardIterator1 __match = __first1;
for (; __match != __i; ++__match)
if (__pred(*__match, *__i))
break;
if (__match == __i) {
// Count number of *__i in [f2, l2)
_D1 __c2 = 0;
for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)