Thread: Trying to get to the bottom of a myclass::size_type

I have a class PDCstr that stores a null-terminated array of chtypes. A chtype is a 32bit formated character that can be represented in the screen. I use this class as a helper class for PDCurses (a portable curses implementation) daily usage.

PDCstr, among other things, defines two subscript operator overloads and an observer function:

Code:

chtype& operator[] (const size_type idx) { return chtstr_[idx]; }
const chtype& operator[] (const size_type idx) const { return chtstr_[idx]; }
size_type size() const { return str_.size() );

chtstr_ and str_ are defined as:

Code:

private:
    std::string str_;
    boost::shared_array<chtype> chtstr_;

size_type above is currently being defined as:

Code:

public:
    typedef size_t size_type;

I'm not sure if my typedef is the correct one anymore. I'm divided between what I have now and these two:

Code:

typedef std::string::size_type size_type;

typedef std::ptrdiff_t size_type //boost way (and then assert as boost does)

As a final note, I'm using the std::string (which is initialized from a constructor parameter) to build the null-terminated array of 32bit characters. That is, the array is a character-by-character 32bit representation of the 8bit std::string.