ADT: Add range helpers for pointer_ and pointee_iterator

llvm-svn: 298841

2 files changed, 35 insertions, 0 deletions

diff --git a/llvm/include/llvm/ADT/iterator.h b/llvm/include/llvm/ADT/iterator.h
index 9a134e1557b..8f162da1b54 100644
--- a/llvm/include/llvm/ADT/iterator.h
+++ b/llvm/include/llvm/ADT/iterator.h
@@ -10,6 +10,7 @@
 #ifndef LLVM_ADT_ITERATOR_H
 #define LLVM_ADT_ITERATOR_H
 
+#include "llvm/ADT/iterator_range.h"
 #include <cstddef>
 #include <iterator>
 #include <type_traits>
@@ -290,6 +291,15 @@ struct pointee_iterator
   T &operator*() const { return **this->I; }
 };
 
+template <typename RangeT, typename WrappedIteratorT =
+                               decltype(std::begin(std::declval<RangeT>()))>
+iterator_range<pointee_iterator<WrappedIteratorT>>
+make_pointee_range(RangeT &&Range) {
+  using PointeeIteratorT = pointee_iterator<WrappedIteratorT>;
+  return make_range(PointeeIteratorT(std::begin(std::forward<RangeT>(Range))),
+                    PointeeIteratorT(std::end(std::forward<RangeT>(Range))));
+}
+
 template <typename WrappedIteratorT,
           typename T = decltype(&*std::declval<WrappedIteratorT>())>
 class pointer_iterator
@@ -307,6 +317,15 @@ public:
   const T &operator*() const { return Ptr = &*this->I; }
 };
 
+template <typename RangeT, typename WrappedIteratorT =
+                               decltype(std::begin(std::declval<RangeT>()))>
+iterator_range<pointer_iterator<WrappedIteratorT>>
+make_pointer_range(RangeT &&Range) {
+  using PointerIteratorT = pointer_iterator<WrappedIteratorT>;
+  return make_range(PointerIteratorT(std::begin(std::forward<RangeT>(Range))),
+                    PointerIteratorT(std::end(std::forward<RangeT>(Range))));
+}
+
 } // end namespace llvm
 
 #endif // LLVM_ADT_ITERATOR_H
diff --git a/llvm/unittests/ADT/IteratorTest.cpp b/llvm/unittests/ADT/IteratorTest.cpp
index 0edb98b9343..7f261824b49 100644
--- a/llvm/unittests/ADT/IteratorTest.cpp
+++ b/llvm/unittests/ADT/IteratorTest.cpp
@@ -118,6 +118,15 @@ TEST(PointeeIteratorTest, SmartPointer) {
   EXPECT_EQ(End, I);
 }
 
+TEST(PointeeIteratorTest, Range) {
+  int A[] = {1, 2, 3, 4};
+  SmallVector<int *, 4> V{&A[0], &A[1], &A[2], &A[3]};
+
+  int I = 0;
+  for (int II : make_pointee_range(V))
+    EXPECT_EQ(A[I++], II);
+}
+
 TEST(FilterIteratorTest, Lambda) {
   auto IsOdd = [](int N) { return N % 2 == 1; };
   int A[] = {0, 1, 2, 3, 4, 5, 6};
@@ -211,6 +220,13 @@ TEST(PointerIterator, Const) {
   EXPECT_EQ(A + 4, std::next(*Begin, 4));
 }
 
+TEST(PointerIterator, Range) {
+  int A[] = {1, 2, 3, 4};
+  int I = 0;
+  for (int *P : make_pointer_range(A))
+    EXPECT_EQ(A + I++, P);
+}
+
 TEST(ZipIteratorTest, Basic) {
   using namespace std;
   const SmallVector<unsigned, 6> pi{3, 1, 4, 1, 5, 9};