ResizableArray.h

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/////////////////////////////////////////////////////////////////////
///
/// ResizableArray.h
///
/////////////////////////////////////////////////////////////////////
#ifndef __ResizableArray_H__
#define __ResizableArray_H__

/////////////////////////////////////////////////////////////////////
/// @addtogroup GlobalFunctions
/** @{ */

/////////////////////////////////////////////////////////////////////
/// A data structure that provides a resizable array
/// This is used within Spam to avoid reading input data files multiple times,
/// without having to use any STL library classes
/////////////////////////////////////////////////////////////////////
class ResizableArray
{
public:
    /////////////////////////////////////////////////////////////////////
    /// Allocate the memory for the initial size of the array
    ///
    /// @param initialSize
    /////////////////////////////////////////////////////////////////////
    ResizableArray(int initialSize)
    {
        _memory = new int[initialSize];
        memSize = initialSize;
        length = 0;
    };

    /////////////////////////////////////////////////////////////////////
    /// Allocate the memory for the default initial size of the array
    ///
    /////////////////////////////////////////////////////////////////////
    ResizableArray()
    {
        ResizableArray(DEFAULT_INITIAL_SIZE);
    };

    /////////////////////////////////////////////////////////////////////
    /// Destructor
    /////////////////////////////////////////////////////////////////////
    ~ResizableArray()
    {
        delete [] _memory;
    };

    /////////////////////////////////////////////////////////////////////
    /// Push an item onto the end of the array, resizing
    /// the local copy in memory if necessary
    ///
    /// @param item The item to add
    /////////////////////////////////////////////////////////////////////
    void Add(int item)
    {
        if (length < memSize)
        {
            _memory[length] = item;
        }
        else
        {
            // Double the size of our local array

            // Allocate a temp array with double the size
            int * newMem = new int[memSize*2];
            memcpy(newMem, _memory, sizeof(int)*memSize);
            delete [] _memory;

            // Set _memory to temp
            _memory = newMem;
            _memory[length] = item;
            memSize = memSize*2;
        }
        length++;
    };

    /////////////////////////////////////////////////////////////////////
    /// Return a copy of the data in the ResizableArray
    ///
    /// @param arr The memory location to copy the array
    /// @param len The number of elements in the array
    /////////////////////////////////////////////////////////////////////
    void ToArray(int *&arr, int &len)
    {
        len = length;
        arr = new int[len];
        memcpy(arr, _memory, sizeof(int)*len);
    };

private:
    static const int DEFAULT_INITIAL_SIZE = 16;

    // --- private variables
    int * _memory;  // The internal array memory
    int memSize;        // The actual size of memory that is allocated
    int length;         // The number of items the user has added
}
; // class ResizableArray

/** @} */
#endif

---