ADT: Add ilist_node::get{Prev,Next}Node, which return the adjacent node or null.
- This provides a convenient alternative to using something llvm::prior or
manual iterator access, for example::
if (T *Prev = foo->getPrevNode())
...
instead of::
iterator it(foo);
if (it != begin()) {
--it;
...
}
- Chris, please review.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103647 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/ADT/ilist_node.h b/include/llvm/ADT/ilist_node.h
index da25f95..3de4f15 100644
--- a/include/llvm/ADT/ilist_node.h
+++ b/include/llvm/ADT/ilist_node.h
@@ -49,6 +49,56 @@
void setNext(NodeTy *N) { Next = N; }
protected:
ilist_node() : Next(0) {}
+
+public:
+ /// @name Adjacent Node Accessors
+ /// @{
+
+ /// \brief Get the previous node, or 0 for the list head.
+ NodeTy *getPrevNode() {
+ NodeTy *Prev = this->getPrev();
+
+ // Check for sentinel.
+ if (!Prev->getNext())
+ return 0;
+
+ return Prev;
+ }
+
+ /// \brief Get the previous node, or 0 for the list head.
+ const NodeTy *getPrevNode() const {
+ NodeTy *Prev = this->getPrev();
+
+ // Check for sentinel.
+ if (!Prev->getNext())
+ return 0;
+
+ return Prev;
+ }
+
+ /// \brief Get the next node, or 0 for the list tail.
+ NodeTy *getNextNode() {
+ NodeTy *Next = getNext();
+
+ // Check for sentinel.
+ if (!Next->getNext())
+ return 0;
+
+ return Next;
+ }
+
+ /// \brief Get the next node, or 0 for the list tail.
+ const NodeTy *getNextNode() const {
+ NodeTy *Next = getNext();
+
+ // Check for sentinel.
+ if (!Next->getNext())
+ return 0;
+
+ return Next;
+ }
+
+ /// @}
};
} // End llvm namespace
diff --git a/unittests/ADT/ilistTest.cpp b/unittests/ADT/ilistTest.cpp
new file mode 100644
index 0000000..3bf04dc
--- /dev/null
+++ b/unittests/ADT/ilistTest.cpp
@@ -0,0 +1,39 @@
+//===- llvm/unittest/ADT/APInt.cpp - APInt unit tests ---------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include <ostream>
+#include "gtest/gtest.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/ADT/ilist_node.h"
+
+using namespace llvm;
+
+namespace {
+
+struct Node : ilist_node<Node> {
+ int Value;
+
+ Node() {}
+ Node(int _Value) : Value(_Value) {}
+};
+
+TEST(ilistTest, Basic) {
+ ilist<Node> List;
+ List.push_back(Node(1));
+ EXPECT_EQ(1, List.back().Value);
+ EXPECT_EQ(0, List.back().getPrevNode());
+ EXPECT_EQ(0, List.back().getNextNode());
+
+ List.push_back(Node(2));
+ EXPECT_EQ(2, List.back().Value);
+ EXPECT_EQ(2, List.front().getNextNode()->Value);
+ EXPECT_EQ(1, List.back().getPrevNode()->Value);
+}
+
+}