source: Sophya/trunk/SophyaExt/Blitz/blitz/array/multi.h@ 701

// Support for multicomponent arrays

#ifndef BZ_ARRAYMULTI_H
#define BZ_ARRAYMULTI_H

#ifndef BZ_ARRAY_H
 #error <blitz/array/multi.h> must be included via <blitz/array.h>
#endif

BZ_NAMESPACE(blitz)

/*
 * The multicomponent_traits class provides a mapping from multicomponent
 * tuples to the element type they contain.  For example:
 *
 * multicomponent_traits<complex<float> >::T_numtype is float,
 * multicomponent_traits<TinyVector<int,3> >::T_numtype is int.
 *
 * This is used to support Array<T,N>::operator[], which extracts components
 * from a multicomponent array.
 */

// By default, produce a harmless component type, and zero components.
template<class T_component>
struct multicomponent_traits {
    typedef T_component T_element;
    enum { numComponents = 0 };
};

// TinyVector
template<class T_numtype, int N_rank>
struct multicomponent_traits<TinyVector<T_numtype,N_rank> > {
    typedef T_numtype T_element;
    enum { numComponents = N_rank };
};

// complex<T>
template<class T>
struct multicomponent_traits<complex<T> > {
    typedef T T_element;
    enum { numComponents = 2 };
};

// This macro is provided so that users can register their own
// multicomponent types.

#define BZ_DECLARE_MULTICOMPONENT_TYPE(T_tuple,T,N)          \
  template<>                                                 \
  struct multicomponent_traits<T_tuple > {                   \
    typedef T T_element;                                     \
    enum { numComponents = N };                              \
  };

BZ_NAMESPACE_END

#endif // BZ_ARRAYMULTI_H