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#ifndef V8_SPLAY_TREE_H_
#define V8_SPLAY_TREE_H_
#include "allocation.h"
namespace v8 {
namespace internal {
// A splay tree. The config type parameter encapsulates the different
// configurations of a concrete splay tree:
//
// typedef Key: the key type
// typedef Value: the value type
// static const kNoKey: the dummy key used when no key is set
// static const kNoValue: the dummy value used to initialize nodes
// int (Compare)(Key& a, Key& b) -> {-1, 0, 1}: comparison function
//
// The tree is also parameterized by an allocation policy
// (Allocator). The policy is used for allocating lists in the C free
// store or the zone; see zone.h.
// Forward defined as
// template <typename Config, class Allocator = FreeStoreAllocationPolicy>
// class SplayTree;
template <typename Config, class AllocationPolicy>
class SplayTree {
public:
typedef typename Config::Key Key;
typedef typename Config::Value Value;
class Locator;
SplayTree(AllocationPolicy allocator = AllocationPolicy())
: root_(NULL), allocator_(allocator) { }
~SplayTree();
INLINE(void* operator new(size_t size,
AllocationPolicy allocator = AllocationPolicy())) {
return allocator.New(static_cast<int>(size));
}
INLINE(void operator delete(void* p)) {
AllocationPolicy::Delete(p);
}
// Please the MSVC compiler. We should never have to execute this.
INLINE(void operator delete(void* p, AllocationPolicy policy)) {
UNREACHABLE();
}
// Inserts the given key in this tree with the given value. Returns
// true if a node was inserted, otherwise false. If found the locator
// is enabled and provides access to the mapping for the key.
bool Insert(const Key& key, Locator* locator);
// Looks up the key in this tree and returns true if it was found,
// otherwise false. If the node is found the locator is enabled and
// provides access to the mapping for the key.
bool Find(const Key& key, Locator* locator);
// Finds the mapping with the greatest key less than or equal to the
// given key.
bool FindGreatestLessThan(const Key& key, Locator* locator);
// Find the mapping with the greatest key in this tree.
bool FindGreatest(Locator* locator);
// Finds the mapping with the least key greater than or equal to the
// given key.
bool FindLeastGreaterThan(const Key& key, Locator* locator);
// Find the mapping with the least key in this tree.
bool FindLeast(Locator* locator);
// Move the node from one key to another.
bool Move(const Key& old_key, const Key& new_key);
// Remove the node with the given key from the tree.
bool Remove(const Key& key);
bool is_empty() { return root_ == NULL; }
// Perform the splay operation for the given key. Moves the node with
// the given key to the top of the tree. If no node has the given
// key, the last node on the search path is moved to the top of the
// tree.
void Splay(const Key& key);
class Node {
public:
Node(const Key& key, const Value& value)
: key_(key),
value_(value),
left_(NULL),
right_(NULL) { }
INLINE(void* operator new(size_t size, AllocationPolicy allocator)) {
return allocator.New(static_cast<int>(size));
}
INLINE(void operator delete(void* p)) {
return AllocationPolicy::Delete(p);
}
// Please the MSVC compiler. We should never have to execute
// this.
INLINE(void operator delete(void* p, AllocationPolicy allocator)) {
UNREACHABLE();
}
Key key() { return key_; }
Value value() { return value_; }
Node* left() { return left_; }
Node* right() { return right_; }
private:
friend class SplayTree;
friend class Locator;
Key key_;
Value value_;
Node* left_;
Node* right_;
};
// A locator provides access to a node in the tree without actually
// exposing the node.
class Locator BASE_EMBEDDED {
public:
explicit Locator(Node* node) : node_(node) { }
Locator() : node_(NULL) { }
const Key& key() { return node_->key_; }
Value& value() { return node_->value_; }
void set_value(const Value& value) { node_->value_ = value; }
inline void bind(Node* node) { node_ = node; }
private:
Node* node_;
};
template <class Callback>
void ForEach(Callback* callback);
protected:
// Resets tree root. Existing nodes become unreachable.
void ResetRoot() { root_ = NULL; }
private:
// Search for a node with a given key. If found, root_ points
// to the node.
bool FindInternal(const Key& key);
// Inserts a node assuming that root_ is already set up.
void InsertInternal(int cmp, Node* node);
// Removes root_ node.
void RemoveRootNode(const Key& key);
template<class Callback>
class NodeToPairAdaptor BASE_EMBEDDED {
public:
explicit NodeToPairAdaptor(Callback* callback)
: callback_(callback) { }
void Call(Node* node) {
callback_->Call(node->key(), node->value());
}
private:
Callback* callback_;
DISALLOW_COPY_AND_ASSIGN(NodeToPairAdaptor);
};
class NodeDeleter BASE_EMBEDDED {
public:
NodeDeleter() { }
void Call(Node* node) { AllocationPolicy::Delete(node); }
private:
DISALLOW_COPY_AND_ASSIGN(NodeDeleter);
};
template <class Callback>
void ForEachNode(Callback* callback);
Node* root_;
AllocationPolicy allocator_;
DISALLOW_COPY_AND_ASSIGN(SplayTree);
};
} } // namespace v8::internal
#endif // V8_SPLAY_TREE_H_