writebuf.hpp

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//
// Copyright (C) 2014, 2015 Ableton AG, Berlin. All rights reserved.
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#pragma once

#include <atria/xform/transducer_impl.hpp>
#include <functional>
#include <iterator>
#include <ios>

namespace atria {
namespace xform {

namespace detail {

struct writebuf_rf_gen
{
  template <typename ReducingFnT, typename OutputStreamRefT>
  struct apply
  {
    ReducingFnT step;
    OutputStreamRefT stream_ref;

    template <typename StateT, typename InputT, typename ...InputTs>
    auto operator() (StateT&& s, InputT&& buf, InputTs&& ...is)
      -> decltype(step(std::forward<StateT>(s),
                       std::forward<InputT>(buf),
                       std::forward<InputTs>(is)...))
    {
      using std::begin;
      using std::end;

      auto& stream = stream_ref.get();
      auto first = begin(buf);
      auto last = end(buf);
      stream.write(&*first, static_cast<std::streamsize>(
                     std::distance(first, last)));
      return step(std::forward<StateT>(s),
                  std::forward<InputT>(buf),
                  std::forward<InputTs>(is)...);
    }
  };
};

} // namespace detail

template <typename OutputStreamRefT>
using writebuf_t = transducer_impl<detail::writebuf_rf_gen, OutputStreamRefT>;

template <typename OutputStreamT>
auto writebuf(OutputStreamT& stream)
  -> writebuf_t<std::reference_wrapper<OutputStreamT> >
{
  return { std::ref(stream) };
}

} // namespace xform
} // namespace atria