[PATCH] D23703: [ADT] Add pointer_iterator, the opposite of pointee_iterator

[Tim Shen via llvm-commits]

timshen created this revision.
timshen added a reviewer: dblaikie.
timshen added a subscriber: llvm-commits.

https://reviews.llvm.org/D23703

Files:
  include/llvm/ADT/iterator.h
  unittests/Support/IteratorTest.cpp

Index: unittests/Support/IteratorTest.cpp
===================================================================
--- unittests/Support/IteratorTest.cpp
+++ unittests/Support/IteratorTest.cpp
@@ -185,4 +185,18 @@
   EXPECT_EQ((SmallVector<int, 3>{1, 3, 5}), Actual);
 }
 
+TEST(PointerIterator, Basic) {
+  int A[] = {1, 2, 3, 4};
+  pointer_iterator<int *> Begin(std::begin(A)), End(std::end(A));
+  EXPECT_EQ(A, *Begin);
+  ++Begin;
+  EXPECT_EQ(A + 1, *Begin);
+  ++Begin;
+  EXPECT_EQ(A + 2, *Begin);
+  ++Begin;
+  EXPECT_EQ(A + 3, *Begin);
+  ++Begin;
+  EXPECT_EQ(Begin, End);
+}
+
 } // anonymous namespace
Index: include/llvm/ADT/iterator.h
===================================================================
--- include/llvm/ADT/iterator.h
+++ include/llvm/ADT/iterator.h
@@ -256,6 +256,19 @@
   T &operator*() const { return **this->I; }
 };
 
+template <typename WrappedIteratorT,
+          typename T = decltype(&*std::declval<WrappedIteratorT>())>
+struct pointer_iterator
+    : iterator_adaptor_base<pointer_iterator<WrappedIteratorT>,
+                            WrappedIteratorT, T> {
+  pointer_iterator() {}
+
+  explicit pointer_iterator(WrappedIteratorT u)
+      : pointer_iterator::iterator_adaptor_base(std::move(u)) {}
+
+  T operator*() const { return &*this->I; }
+};
+
 }
 
 #endif


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