#ifndef List_h
#define List_h
namespace bmalloc {
template<typename T>
struct ListNode {
ListNode<T>* prev { nullptr };
ListNode<T>* next { nullptr };
};
template<typename T>
class List {
static_assert(std::is_trivially_destructible<T>::value, "List must have a trivial destructor.");
struct iterator {
T* operator*() { return static_cast<T*>(m_node); }
T* operator->() { return static_cast<T*>(m_node); }
bool operator!=(const iterator& other) { return m_node != other.m_node; }
iterator& operator++()
{
m_node = m_node->next;
return *this;
}
ListNode<T>* m_node { nullptr };
};
public:
List() { }
bool isEmpty() { return m_root.next == &m_root; }
T* head() { return static_cast<T*>(m_root.next); }
T* tail() { return static_cast<T*>(m_root.prev); }
iterator begin() { return iterator { m_root.next }; }
iterator end() { return iterator { &m_root }; }
void push(T* node)
{
ListNode<T>* it = tail();
insertAfter(it, node);
}
void pushFront(T* node)
{
ListNode<T>* it = &m_root;
insertAfter(it, node);
}
T* pop()
{
ListNode<T>* result = tail();
remove(result);
return static_cast<T*>(result);
}
T* popFront()
{
ListNode<T>* result = head();
remove(result);
return static_cast<T*>(result);
}
static void insertAfter(ListNode<T>* it, ListNode<T>* node)
{
ListNode<T>* prev = it;
ListNode<T>* next = it->next;
node->next = next;
next->prev = node;
node->prev = prev;
prev->next = node;
}
static void remove(ListNode<T>* node)
{
ListNode<T>* next = node->next;
ListNode<T>* prev = node->prev;
next->prev = prev;
prev->next = next;
node->prev = nullptr;
node->next = nullptr;
}
private:
ListNode<T> m_root { &m_root, &m_root };
};
}
#endif // List_h