Class SwigPyIterator

swig/python/export_wrap.cpp:3587–3698

  };

  struct SwigPyIterator {
  private:
    SwigPtr_PyObject _seq;

  protected:
    SwigPyIterator(PyObject *seq) : _seq(seq)
    {
    }
      
  public:
    virtual ~SwigPyIterator() {}

    // Access iterator method, required by Python
    virtual PyObject *value() const = 0;

    // Forward iterator method, required by Python
    virtual SwigPyIterator *incr(size_t n = 1) = 0;
    
    // Backward iterator method, very common in C++, but not required in Python
    virtual SwigPyIterator *decr(size_t /*n*/ = 1)
    {
      throw stop_iteration();
    }

    // Random access iterator methods, but not required in Python
    virtual ptrdiff_t distance(const SwigPyIterator &/*x*/) const
    {
      throw std::invalid_argument("operation not supported");
    }

    virtual bool equal (const SwigPyIterator &/*x*/) const
    {
      throw std::invalid_argument("operation not supported");
    }
    
    // C++ common/needed methods
    virtual SwigPyIterator *copy() const = 0;

    PyObject *next()     
    {
      SWIG_PYTHON_THREAD_BEGIN_BLOCK; // disable threads       
      PyObject *obj = value();
      incr();       
      SWIG_PYTHON_THREAD_END_BLOCK; // re-enable threads
      return obj;     
    }

    /* Make an alias for Python 3.x */
    PyObject *__next__()
    {
      return next();
    }

    PyObject *previous()
    {
      SWIG_PYTHON_THREAD_BEGIN_BLOCK; // disable threads       
      decr();
      PyObject *obj = value();