src/list.h

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#ifndef V8_LIST_H_
#define V8_LIST_H_

namespace v8 {
namespace internal {


// ----------------------------------------------------------------------------
// The list is a template for very light-weight lists. We are not
// using the STL because we want full control over space and speed of
// the code. This implementation is based on code by Robert Griesemer
// and Rob Pike.
//
// The list is parameterized by the type of its elements (T) and by an
// allocation policy (P). The policy is used for allocating lists in
// the C free store or the zone; see zone.h.

// Forward defined as
// template <typename T, class P = FreeStoreAllocationPolicy> class List;
template <typename T, class P>
class List {
 public:

  List() { Initialize(0); }
  INLINE(explicit List(int capacity)) { Initialize(capacity); }
  INLINE(~List()) { DeleteData(data_); }

  // Deallocates memory used by the list and leaves the list in a consistent
  // empty state.
  void Free() {
    DeleteData(data_);
    Initialize(0);
  }

  INLINE(void* operator new(size_t size)) {
      return P::New(static_cast<int>(size));
  }
  INLINE(void operator delete(void* p, size_t)) { return P::Delete(p); }

  // Returns a reference to the element at index i.  This reference is
  // not safe to use after operations that can change the list's
  // backing store (eg, Add).
  inline T& operator[](int i) const {
    ASSERT(0 <= i);
    ASSERT(i < length_);
    return data_[i];
  }
  inline T& at(int i) const { return operator[](i); }
  inline T& last() const { return at(length_ - 1); }
  inline T& first() const { return at(0); }

  INLINE(bool is_empty() const) { return length_ == 0; }
  INLINE(int length() const) { return length_; }
  INLINE(int capacity() const) { return capacity_; }

  Vector<T> ToVector() { return Vector<T>(data_, length_); }

  Vector<const T> ToConstVector() { return Vector<const T>(data_, length_); }

  // Adds a copy of the given 'element' to the end of the list,
  // expanding the list if necessary.
  void Add(const T& element);

  // Add all the elements from the argument list to this list.
  void AddAll(const List<T, P>& other);

  // Inserts the element at the specific index.
  void InsertAt(int index, const T& element);

  // Added 'count' elements with the value 'value' and returns a
  // vector that allows access to the elements.  The vector is valid
  // until the next change is made to this list.
  Vector<T> AddBlock(T value, int count);

  // Removes the i'th element without deleting it even if T is a
  // pointer type; moves all elements above i "down". Returns the
  // removed element.  This function's complexity is linear in the
  // size of the list.
  T Remove(int i);

  // Remove the given element from the list. Returns whether or not
  // the input is included in the list in the first place.
  bool RemoveElement(const T& elm);

  // Removes the last element without deleting it even if T is a
  // pointer type. Returns the removed element.
  INLINE(T RemoveLast()) { return Remove(length_ - 1); }

  // Clears the list by setting the length to zero. Even if T is a
  // pointer type, clearing the list doesn't delete the entries.
  INLINE(void Clear());

  // Drops all but the first 'pos' elements from the list.
  INLINE(void Rewind(int pos));

  // Drop the last 'count' elements from the list.
  INLINE(void RewindBy(int count)) { Rewind(length_ - count); }

  bool Contains(const T& elm) const;
  int CountOccurrences(const T& elm, int start, int end) const;

  // Iterate through all list entries, starting at index 0.
  void Iterate(void (*callback)(T* x));
  template<class Visitor>
  void Iterate(Visitor* visitor);

  // Sort all list entries (using QuickSort)
  void Sort(int (*cmp)(const T* x, const T* y));
  void Sort();

  INLINE(void Initialize(int capacity));

 private:
  T* data_;
  int capacity_;
  int length_;

  INLINE(T* NewData(int n))  { return static_cast<T*>(P::New(n * sizeof(T))); }
  INLINE(void DeleteData(T* data))  { P::Delete(data); }

  // Increase the capacity of a full list, and add an element.
  // List must be full already.
  void ResizeAdd(const T& element);

  // Inlined implementation of ResizeAdd, shared by inlined and
  // non-inlined versions of ResizeAdd.
  void ResizeAddInternal(const T& element);

  // Resize the list.
  void Resize(int new_capacity);

  DISALLOW_COPY_AND_ASSIGN(List);
};

} }  // namespace v8::internal

#endif  // V8_LIST_H_