Add MIPS Technologies to the vendors in llvm::Triple.

[oota-llvm.git] / include / llvm / ADT / ilist_node.h

diff --git a/include/llvm/ADT/ilist_node.h b/include/llvm/ADT/ilist_node.h
index 86d5a500f89eb7697573d2857c8e843ec5fd86ba..85aa7a4b1f7fbaf1ad37aab09260e540f777a552 100644 (file)
--- a/include/llvm/ADT/ilist_node.h
+++ b/include/llvm/ADT/ilist_node.h
@@ -12,34 +12,93 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_ADT_ILIST_NODE_H
-#define LLVM_ADT_ILIST_NODE_H
+#ifndef LLVM_ADT_ILISTNODE_H
+#define LLVM_ADT_ILISTNODE_H
 
 namespace llvm {
 
 template<typename NodeTy>
-struct ilist_nextprev_traits;
+struct ilist_traits;
 
+/// ilist_half_node - Base class that provides prev services for sentinels.
+///
 template<typename NodeTy>
-struct ilist_traits;
+class ilist_half_node {
+  friend struct ilist_traits<NodeTy>;
+  NodeTy *Prev;
+protected:
+  NodeTy *getPrev() { return Prev; }
+  const NodeTy *getPrev() const { return Prev; }
+  void setPrev(NodeTy *P) { Prev = P; }
+  ilist_half_node() : Prev(nullptr) {}
+};
+
+template<typename NodeTy>
+struct ilist_nextprev_traits;
 
 /// ilist_node - Base class that provides next/prev services for nodes
 /// that use ilist_nextprev_traits or ilist_default_traits.
 ///
 template<typename NodeTy>
-class ilist_node {
-private:
+class ilist_node : private ilist_half_node<NodeTy> {
   friend struct ilist_nextprev_traits<NodeTy>;
-  NodeTy *Prev, *Next;
-  NodeTy *getPrev() { return Prev; }
+  friend struct ilist_traits<NodeTy>;
+  NodeTy *Next;
   NodeTy *getNext() { return Next; }
-  const NodeTy *getPrev() const { return Prev; }
   const NodeTy *getNext() const { return Next; }
-  void setPrev(NodeTy *N) { Prev = N; }
   void setNext(NodeTy *N) { Next = N; }
 protected:
-  ilist_node() : Prev(0), Next(0) {}
-  friend struct ilist_traits<NodeTy>;
+  ilist_node() : Next(nullptr) {}
+
+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 nullptr;
+
+    return Prev;
+  }
+
+  /// \brief Get the previous node, or 0 for the list head.
+  const NodeTy *getPrevNode() const {
+    const NodeTy *Prev = this->getPrev();
+
+    // Check for sentinel.
+    if (!Prev->getNext())
+      return nullptr;
+
+    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 nullptr;
+
+    return Next;
+  }
+
+  /// \brief Get the next node, or 0 for the list tail.
+  const NodeTy *getNextNode() const {
+    const NodeTy *Next = getNext();
+
+    // Check for sentinel.
+    if (!Next->getNext())
+      return nullptr;
+
+    return Next;
+  }
+
+  /// @}
 };
 
 } // End llvm namespace