[llvm-commits] [llvm] r103647 - in /llvm/trunk: include/llvm/ADT/ilist_node.h unittests/ADT/ilistTest.cpp

[Daniel Dunbar]

Author: ddunbar
Date: Wed May 12 16:35:19 2010
New Revision: 103647

URL: http://llvm.org/viewvc/llvm-project?rev=103647&view=rev
Log:
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.

Added:
    llvm/trunk/unittests/ADT/ilistTest.cpp
Modified:
    llvm/trunk/include/llvm/ADT/ilist_node.h

Modified: llvm/trunk/include/llvm/ADT/ilist_node.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/ilist_node.h?rev=103647&r1=103646&r2=103647&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/ilist_node.h (original)
+++ llvm/trunk/include/llvm/ADT/ilist_node.h Wed May 12 16:35:19 2010
@@ -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

Added: llvm/trunk/unittests/ADT/ilistTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/ilistTest.cpp?rev=103647&view=auto
==============================================================================
--- llvm/trunk/unittests/ADT/ilistTest.cpp (added)
+++ llvm/trunk/unittests/ADT/ilistTest.cpp Wed May 12 16:35:19 2010
@@ -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);
+}
+
+}