stream_transpose.hpp

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// vim: set tabstop=2:softtabstop=2:shiftwidth=2:expandtab

#ifndef LIN_CORE_OPERATIONS_STREAM_TRANSPOSE_HPP_
#define LIN_CORE_OPERATIONS_STREAM_TRANSPOSE_HPP_

namespace lin {
namespace internal {

template <class C>
class StreamTranspose : public Stream<StreamTranspose<C>> {
 private:
  Stream<C> const &c;

 public:
  typedef traits<StreamTranspose<C>> Traits;

 protected:
  using Stream<StreamTranspose<C>>::derived;

 public:
  using Stream<StreamTranspose<C>>::size;
  using Stream<StreamTranspose<C>>::eval;

  constexpr StreamTranspose() = delete;
  constexpr StreamTranspose(StreamTranspose<C> const &) = default;
  constexpr StreamTranspose(StreamTranspose<C> &&) = default;
  constexpr StreamTranspose<C> &operator=(StreamTranspose<C> const &) = default;
  constexpr StreamTranspose<C> &operator=(StreamTranspose<C> &&) = default;

  constexpr StreamTranspose(Stream<C> const &c)
  : c(c) { }

  constexpr size_t rows() const {
    return c.cols();
  }

  constexpr size_t cols() const {
    return c.rows();
  }

  constexpr typename Traits::elem_t operator()(size_t i, size_t j) const {
    return c(j, i);
  }

  constexpr typename Traits::elem_t operator()(size_t i) const {
    return (*this)(i / cols(), i % cols());
  }
};

template <class C>
struct _elem<StreamTranspose<C>> : _elem<C> { };

template <class C>
struct _dims<StreamTranspose<C>> {
  static constexpr size_t rows = _dims<C>::cols;
  static constexpr size_t cols = _dims<C>::rows;
  static constexpr size_t max_rows = _dims<C>::max_cols;
  static constexpr size_t max_cols = _dims<C>::max_rows;
};
}  // namespace internal
}  // namespace lin

#endif