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// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_LIST_H_
#define V8_LIST_H_
#include <algorithm>
#include "src/checks.h"
#include "src/vector.h"
namespace v8 {
namespace internal {
template<typename T> class Vector;
// ----------------------------------------------------------------------------
// 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 AllocationPolicy = FreeStoreAllocationPolicy> class List;
template <typename T, class AllocationPolicy>
class List {
explicit List(AllocationPolicy allocator = AllocationPolicy()) {
Initialize(0, allocator);
INLINE(explicit List(int capacity,
AllocationPolicy allocator = AllocationPolicy())) {
Initialize(capacity, allocator);
INLINE(~List()) { DeleteData(data_); }
// Deallocates memory used by the list and leaves the list in a consistent
// empty state.
void Free() {
INLINE(void* operator new(size_t size,
AllocationPolicy allocator = AllocationPolicy())) {
return allocator.New(static_cast<int>(size));
INLINE(void operator delete(void* p)) {
// Please the MSVC compiler. We should never have to execute this.
INLINE(void operator delete(void* p, AllocationPolicy allocator)) {
// 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 (e.g. Add).
inline T& operator[](int i) const {
DCHECK_LE(0, i);
DCHECK_GT(static_cast<unsigned>(length_), static_cast<unsigned>(i));
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); }
typedef T* iterator;
inline iterator begin() const { return &data_[0]; }
inline iterator end() const { return &data_[length_]; }
INLINE(bool is_empty() const) { return length_ == 0; }
INLINE(int length() const) { return length_; }
INLINE(int capacity() const) { return capacity_; }
Vector<T> ToVector() const { return Vector<T>(data_, length_); }
Vector<const T> ToConstVector() const {
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, AllocationPolicy allocator = AllocationPolicy());
// Add all the elements from the argument list to this list.
void AddAll(const List<T, AllocationPolicy>& other,
AllocationPolicy allocator = AllocationPolicy());
// Add all the elements from the vector to this list.
void AddAll(const Vector<T>& other,
AllocationPolicy allocator = AllocationPolicy());
// Inserts the element at the specific index.
void InsertAt(int index, const T& element,
AllocationPolicy allocator = AllocationPolicy());
// Overwrites the element at the specific index.
void Set(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,
AllocationPolicy allocator = AllocationPolicy());
// 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); }
// Deletes current list contents and allocates space for 'length' elements.
INLINE(void Allocate(int length,
AllocationPolicy allocator = AllocationPolicy()));
// Clears the list by freeing the storage memory. If you want to keep the
// memory, use Rewind(0) instead. Be aware, that 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); }
// Swaps the contents of the two lists.
INLINE(void Swap(List<T, AllocationPolicy>* list));
// Halve the capacity if fill level is less than a quarter.
INLINE(void Trim(AllocationPolicy allocator = AllocationPolicy()));
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)
template <typename CompareFunction>
void Sort(CompareFunction cmp, size_t start, size_t length);
template <typename CompareFunction>
void Sort(CompareFunction cmp);
void Sort();
template <typename CompareFunction>
void StableSort(CompareFunction cmp, size_t start, size_t length);
template <typename CompareFunction>
void StableSort(CompareFunction cmp);
void StableSort();
INLINE(void Initialize(int capacity,
AllocationPolicy allocator = AllocationPolicy())) {
DCHECK(capacity >= 0);
data_ = (capacity > 0) ? NewData(capacity, allocator) : NULL;
capacity_ = capacity;
length_ = 0;
T* data_;
int capacity_;
int length_;
INLINE(T* NewData(int n, AllocationPolicy allocator)) {
return static_cast<T*>(allocator.New(n * sizeof(T)));
INLINE(void DeleteData(T* data)) {
// Increase the capacity of a full list, and add an element.
// List must be full already.
void ResizeAdd(const T& element, AllocationPolicy allocator);
// Inlined implementation of ResizeAdd, shared by inlined and
// non-inlined versions of ResizeAdd.
void ResizeAddInternal(const T& element, AllocationPolicy allocator);
// Resize the list.
void Resize(int new_capacity, AllocationPolicy allocator);
template<typename T, class P>
size_t GetMemoryUsedByList(const List<T, P>& list) {
return list.length() * sizeof(T) + sizeof(list);
class Map;
class FieldType;
class Code;
template<typename T> class Handle;
typedef List<Map*> MapList;
typedef List<Code*> CodeList;
typedef List<Handle<Map> > MapHandleList;
typedef List<Handle<FieldType> > TypeHandleList;
typedef List<Handle<Code> > CodeHandleList;
// Perform binary search for an element in an already sorted
// list. Returns the index of the element of -1 if it was not found.
// |cmp| is a predicate that takes a pointer to an element of the List
// and returns +1 if it is greater, -1 if it is less than the element
// being searched.
template <typename T, class P>
int SortedListBSearch(const List<T>& list, P cmp);
template <typename T>
int SortedListBSearch(const List<T>& list, T elem);
} // namespace internal
} // namespace v8
#endif // V8_LIST_H_