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(0) {}
+};
+
+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>;
friend struct ilist_traits<NodeTy>;
- NodeTy *Prev, *Next;
- NodeTy *getPrev() { return Prev; }
+ 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) {}
+ 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 {
+ 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 {
+ const NodeTy *Next = getNext();
+
+ // Check for sentinel.
+ if (!Next->getNext())
+ return 0;
+
+ return Next;
+ }
+
+ /// @}
};
} // End llvm namespace