/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*/
#ifndef COMMON_ARRAY_H
#define COMMON_ARRAY_H
#include "common/scummsys.h"
#include "common/algorithm.h"
namespace Common {
/**
* This class implements a dynamically sized container, which
* can be accessed similar to a regular C++ array. Accessing
* elements is performed in constant time (like with plain arrays).
* In addition, one can append, insert and remove entries (this
* is the 'dynamic' part). Doing that in general takes time
* proportional to the number of elements in the array.
*
* The container class closest to this in the C++ standard library is
* std::vector. However, there are some differences. The most important one is
* that std::vector has a far more sophisticated (and complicated) memory
* management scheme. There, only elements that 'live' are actually constructed
* (i.e., have their constructor called), and objects that are removed are
* immediately destructed (have their destructor called).
* With Common::Array, this is not the case; instead, it simply uses new[] and
* delete[] to allocate whole blocks of objects, possibly more than are
* currently 'alive'. This simplifies memory management, but may have
* undesirable side effects when one wants to use an Array of complex
* data types.
*
* @todo Improve the storage management of this class.
* In particular, don't use new[] and delete[], but rather
* construct/destruct objects manually. This way, we can
* ensure that storage which is not currently used does not
* correspond to a live active object.
* (This is only of interest for array of non-POD objects).
*/
template<class T>
class Array {
protected:
uint _capacity;
uint _size;
T *_storage;
public:
typedef T *iterator;
typedef const T *const_iterator;
typedef T value_type;
public:
Array() : _capacity(0), _size(0), _storage(0) {}
Array(const Array<T> &array) : _capacity(array._size), _size(array._size), _storage(0) {
if (array._storage) {
_storage = new T[_capacity];
assert(_storage);
copy(array._storage, array._storage + _size, _storage);
}
}
/**
* Construct an array by copying data from a regular array.
*/
template<class T2>
Array(const T2 *data, int n) {
_capacity = _size = n;
_storage = new T[_capacity];
assert(_storage);
copy(data, data + _size, _storage);
}
~Array() {
delete[] _storage;
_storage = 0;
_capacity = _size = 0;
}
/** Appends element to the end of the array. */
void push_back(const T &element) {
if (_size + 1 <= _capacity)
_storage[_size++] = element;
else
insert_aux(end(), &element, &element + 1);
}
void push_back(const Array<T> &array) {
if (_size + array.size() <= _capacity) {
copy(array.begin(), array.end(), end());
_size += array.size();
} else
insert_aux(end(), array.begin(), array.end());
}
/** Removes the last element of the array. */
void pop_back() {
assert(_size > 0);
_size--;
}
/** Returns a reference to the first element of the array. */
T &front() {
assert(_size > 0);
return _storage[0];
}
/** Returns a reference to the first element of the array. */
const T &front() const {
assert(_size > 0);
return _storage[0];
}
/** Returns a reference to the last element of the array. */
T &back() {
assert(_size > 0);
return _storage[_size-1];
}
/** Returns a reference to the last element of the array. */
const T &back() const {
assert(_size > 0);
return _storage[_size-1];
}
void insert_at(int idx, const T &element) {
assert(idx >= 0 && (uint)idx <= _size);
insert_aux(_storage + idx, &element, &element + 1);
}
T remove_at(int idx) {
assert(idx >= 0 && (uint)idx < _size);
T tmp = _storage[idx];
copy(_storage + idx + 1, _storage + _size, _storage + idx);
_size--;
return tmp;
}
// TODO: insert, remove, ...
T& operator[](int idx) {
assert(idx >= 0 && (uint)idx < _size);
return _storage[idx];
}
const T& operator[](int idx) const {
assert(idx >= 0 && (uint)idx < _size);
return _storage[idx];
}
Array<T>& operator=(const Array<T> &array) {
if (this == &array)
return *this;
delete[] _storage;
_size = array._size;
_capacity = _size + 32;
_storage = new T[_capacity];
assert(_storage);
copy(array._storage, array._storage + _size, _storage);
return *this;
}
uint size() const {
return _size;
}
void clear() {
delete[] _storage;
_storage = 0;
_size = 0;
_capacity = 0;
}
bool empty() const {
return (_size == 0);
}
bool operator==(const Array<T> &other) const {
if (this == &other)
return true;
if (_size != other._size)
return false;
for (uint i = 0; i < _size; ++i) {
if (_storage[i] != other._storage[i])
return false;
}
return true;
}
bool operator!=(const Array<T> &other) const {
return !(*this == other);
}
iterator begin() {
return _storage;
}
iterator end() {
return _storage + _size;
}
const_iterator begin() const {
return _storage;
}
const_iterator end() const {
return _storage + _size;
}
void reserve(uint newCapacity) {
if (newCapacity <= _capacity)
return;
T *old_storage = _storage;
_capacity = newCapacity;
_storage = new T[newCapacity];
assert(_storage);
if (old_storage) {
// Copy old data
copy(old_storage, old_storage + _size, _storage);
delete[] old_storage;
}
}
void resize(uint newSize) {
reserve(newSize);
for (uint i = _size; i < newSize; ++i)
_storage[i] = T();
_size = newSize;
}
protected:
static uint roundUpCapacity(uint capacity) {
// Round up capacity to the next power of 2;
// we use a minimal capacity of 8.
uint capa = 8;
while (capa < capacity)
capa <<= 1;
return capa;
}
/**
* Insert a range of elements coming from this or another array.
* Unlike std::vector::insert, this method does not accept
* arbitrary iterators, mainly because our iterator system is
* seriously limited and does not distinguish between input iterators,
* output iterators, forward iterators or random access iterators.
*
* So, we simply restrict to Array iterators. Extending this to arbitrary
* random access iterators would be trivial.
*
* Moreover, this method does not handle all cases of inserting a subrange
* of an array into itself; this is why it is private for now.
*/
iterator insert_aux(iterator pos, const_iterator first, const_iterator last) {
assert(_storage <= pos && pos <= _storage + _size);
assert(first <= last);
const uint n = last - first;
if (n) {
const uint idx = pos - _storage;
T *newStorage = _storage;
if (_size + n > _capacity) {
// If there is not enough space, allocate more and
// copy old elements over.
uint newCapacity = roundUpCapacity(_size + n);
newStorage = new T[newCapacity];
assert(newStorage);
copy(_storage, _storage + idx, newStorage);
pos = newStorage + idx;
}
// Make room for the new elements by shifting back
// existing ones.
copy_backward(_storage + idx, _storage + _size, newStorage + _size + n);
// Insert the new elements.
copy(first, last, pos);
// Finally, update the internal state
if (newStorage != _storage) {
delete[] _storage;
_capacity = roundUpCapacity(_size + n);
_storage = newStorage;
}
_size += n;
}
return pos;
}
};
} // End of namespace Common
#endif