动态数组

from Arcemu code:

 

/*
 * Copyright (c) 2001 Jani Kajala
 *
 * Permission to use, copy, modify, distribute and sell this
 * software and its documentation for any purpose is hereby
 * granted without fee, provided that the above copyright notice
 * appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation.
 * Jani Kajala makes no representations about the suitability
 * of this software for any purpose. It is provided "as is"
 * without express or implied warranty.
 */

#ifndef _DEV_ARRAY_H
#define _DEV_ARRAY_H

/** Very simple dynamic array. */
template <class T> class Array
{
	public:
		/** Creates an empty array. */
		Array() :
			m_data(0), m_len(0), m_cap(0)
		{
		}

		/** Creates an array of specified size. */
		explicit Array(int size) :
			m_data(0), m_len(0), m_cap(0)
		{
			setSize(size);
		}

		///
		~Array()
		{
			delete[] m_data;
		}

		/** Appends an item at the end of the array. */
		void add(const T & item)
		{
			if(m_len + 1 > m_cap)
				setCapacity(m_len + 1);
			m_data[m_len++] = item;
		}

		/** Resizes the array. */
		void setSize(int size)
		{
			if(size > m_cap)
				setCapacity(size);
			m_len = size;
		}

		/** Returns ith item. */
		T & operator[](int i)
		{
			return m_data[i];
		}

		/** Returns pointer to the first element in the vector. */
		T* begin()
		{
			return m_data;
		}

		/** Returns pointer to one beyond the last element in the vector. */
		T* end()
		{
			return m_data + m_len;
		}

		/** Returns number of items in the array. */
		int size() const
		{
			return m_len;
		}

		/** Returns ith item. */
		const T & operator[](int i) const
		{
			return m_data[i];
		}

		/** Returns pointer to the first element in the vector. */
		const T* begin() const
		{
			return m_data;
		}

		/** Returns pointer to one beyond the last element in the vector. */
		const T* end() const
		{
			return m_data + m_len;
		}

	private:
		T*		m_data;
		int		m_len;
		int		m_cap;

		void setCapacity(int cap)
		{
			++cap;
			if(cap < 8)
				cap = 8;
			else if(cap < m_cap * 2)
				cap = m_cap * 2;
			m_cap = cap;

			T* data = new T[cap];
			for(int i = 0 ; i < m_len ; ++i)
				data[i] = m_data[i];
			delete[] m_data;
			m_data = data;
		}
};

#endif // _DEV_ARRAY_H