absDifference.h

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#ifndef NPSTAT_ABSDIFFERENCE_HH_
#define NPSTAT_ABSDIFFERENCE_HH_

#include <cmath>
#include <complex>

#include "Alignment/Geners/interface/IOIsUnsigned.hh"

namespace npstat {
  namespace Private {
    template <typename T>
    struct AbsReturnType {
      typedef T type;
    };

    template <typename T>
    struct AbsReturnType<std::complex<T> > {
      typedef T type;
    };

    template <typename T>
    struct AbsReturnType<const std::complex<T> > {
      typedef T type;
    };

    template <typename T>
    struct AbsReturnType<volatile std::complex<T> > {
      typedef T type;
    };

    template <typename T>
    struct AbsReturnType<const volatile std::complex<T> > {
      typedef T type;
    };

    // Signed type
    template <typename T, int Unsigned = 0>
    struct AbsHelper {
      typedef typename Private::AbsReturnType<T>::type return_type;

      inline static return_type delta(const T& v1, const T& v2) { return std::abs(v1 - v2); }

      inline static return_type value(const T& v1) { return std::abs(v1); }
    };

    // Unsigned type
    template <typename T>
    struct AbsHelper<T, 1> {
      typedef typename Private::AbsReturnType<T>::type return_type;

      inline static return_type delta(const T& v1, const T& v2) { return v1 > v2 ? v1 - v2 : v2 - v1; }

      inline static return_type value(const T& v1) { return v1; }
    };
  }  // namespace Private

  template <typename T>
  inline typename Private::AbsReturnType<T>::type absDifference(const T& v1, const T& v2) {
    return Private::AbsHelper<T, gs::IOIsUnsigned<T>::value>::delta(v1, v2);
  }

  template <typename T>
  inline typename Private::AbsReturnType<T>::type absValue(const T& v1) {
    return Private::AbsHelper<T, gs::IOIsUnsigned<T>::value>::value(v1);
  }
}  // namespace npstat

#endif  // NPSTAT_ABSDIFFERENCE_HH_