gistfile1.c++

template <typename T, std::size_t SIZE=256>
class auto_buffer
{
public:
    typedef T value_type;
    typedef std::size_t size_type;
    typedef T* pointer;
    typedef const T* const_pointer;
    typedef T& reference;
    typedef const T& const_reference;
    static const size_t space = SIZE;
public: // construction
    explicit auto_buffer(size_type size)
        : buffer_((space <  size) ? (T*)malloc(size*sizeof(T)) : &internal_[0]),
          size_((buffer_ != 0) ? size : 0)
    {
    }

    ~auto_buffer() 
    {
        if (space < size_) 
        {
            assert(buffer_ != 0);
            assert(&internal_[0] != buffer_);
            free(buffer_);
        }
    }
public: // operators
    operator pointer() { return buffer_; }
    reference operator[](size_type index) { return buffer_[index]; }
    const_reference operator[](size_type index) const { return buffer_[index]; }
    operator const_pointer() const { return buffer_; }
public:  // accessors
    pointer         data() { return buffer_; }
    const_pointer   data() const { return buffer_; }
    size_type       size() const { return size_; }
    bool            empty() const { return size_ == 0; }
private:
    value_type* buffer_;
    size_type   size_;
    value_type  internal_[SIZE];
};