From fcd69daaa14099e350e937ec4575445b78a72c6c Mon Sep 17 00:00:00 2001 From: "Duncan P. N. Exon Smith" Date: Tue, 7 Feb 2017 21:03:50 +0000 Subject: ADT: Add explicit conversions for reverse ilist iterators Add explicit conversions between forward and reverse ilist iterators. These follow the conversion conventions of std::reverse_iterator, which are off-by-one: the newly-constructed "reverse" iterator dereferences to the previous node of the one sent in. This has the benefit of converting reverse ranges in place: - If [I, E) is a valid range, - then [reverse(E), reverse(I)) gives the same range in reverse order. ilist_iterator::getReverse() is unchanged: it returns a reverse iterator to the *same* node. llvm-svn: 294349 --- llvm/unittests/ADT/IListIteratorTest.cpp | 40 ++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'llvm/unittests/ADT/IListIteratorTest.cpp') diff --git a/llvm/unittests/ADT/IListIteratorTest.cpp b/llvm/unittests/ADT/IListIteratorTest.cpp index ddcab781b9b..7e066c2373a 100644 --- a/llvm/unittests/ADT/IListIteratorTest.cpp +++ b/llvm/unittests/ADT/IListIteratorTest.cpp @@ -131,4 +131,44 @@ TEST(IListIteratorTest, CheckEraseReverse) { EXPECT_EQ(L.rend(), RI); } +TEST(IListIteratorTest, ReverseConstructor) { + simple_ilist L; + const simple_ilist &CL = L; + Node A, B; + L.insert(L.end(), A); + L.insert(L.end(), B); + + // Save typing. + typedef simple_ilist::iterator iterator; + typedef simple_ilist::reverse_iterator reverse_iterator; + typedef simple_ilist::const_iterator const_iterator; + typedef simple_ilist::const_reverse_iterator const_reverse_iterator; + + // Check conversion values. + EXPECT_EQ(L.begin(), iterator(L.rend())); + EXPECT_EQ(++L.begin(), iterator(++L.rbegin())); + EXPECT_EQ(L.end(), iterator(L.rbegin())); + EXPECT_EQ(L.rbegin(), reverse_iterator(L.end())); + EXPECT_EQ(++L.rbegin(), reverse_iterator(++L.begin())); + EXPECT_EQ(L.rend(), reverse_iterator(L.begin())); + + // Check const iterator constructors. + EXPECT_EQ(CL.begin(), const_iterator(L.rend())); + EXPECT_EQ(CL.begin(), const_iterator(CL.rend())); + EXPECT_EQ(CL.rbegin(), const_reverse_iterator(L.end())); + EXPECT_EQ(CL.rbegin(), const_reverse_iterator(CL.end())); + + // Confirm lack of implicit conversions. + static_assert(std::is_convertible::value, + "unexpected implicit conversion"); + static_assert(std::is_convertible::value, + "unexpected implicit conversion"); + static_assert( + std::is_convertible::value, + "unexpected implicit conversion"); + static_assert( + std::is_convertible::value, + "unexpected implicit conversion"); +} + } // end namespace -- cgit v1.2.3