raw_stretcher.hpp

#pragma once
#include <ossia/dataflow/audio_port.hpp>
#include <ossia/dataflow/graph_node.hpp>
#include <ossia/dataflow/nodes/media.hpp>
#include <ossia/dataflow/token_request.hpp>
 
namespace ossia
{
 
struct raw_stretcher
{
  int64_t next_sample_to_read{};
  raw_stretcher() noexcept = default;
  raw_stretcher(const raw_stretcher&) noexcept = default;
  raw_stretcher(raw_stretcher&&) noexcept = default;
  raw_stretcher& operator=(const raw_stretcher&) noexcept = default;
  raw_stretcher& operator=(raw_stretcher&&) noexcept = default;
  raw_stretcher(int64_t pos) noexcept
      : next_sample_to_read{pos}
  {
  }
 
  [[nodiscard]] static constexpr int64_t start_delay() noexcept { return 0; }
 
  void transport(int64_t date) { next_sample_to_read = date; }
 
  template <typename T>
  void
  run(T& audio_fetcher, const ossia::token_request& t, const ossia::exec_state_facade e,
      double tempo_ratio, double rate_ratio, const std::size_t chan,
      const int64_t len, const int64_t samples_to_read, const int64_t samples_to_write,
      const int64_t samples_offset, const ossia::mutable_audio_span<double>& ap) noexcept
  {
    // 1:1; only selected when material and graph rates match.
    (void)rate_ratio;
 
    if(t.forward())
    {
      double** output = (double**)alloca(sizeof(double*) * chan);
      for(std::size_t i = 0; i < chan; i++)
        output[i] = ap[i].data() + samples_offset;
 
      audio_fetcher.fetch_audio(next_sample_to_read, samples_to_write, output);
      next_sample_to_read += samples_to_write;
    }
    else
    {
      // Backward playback
      double** output = (double**)alloca(sizeof(double*) * chan);
      for(std::size_t i = 0; i < chan; i++)
        output[i] = ap[i].data() + samples_offset;
 
      audio_fetcher.fetch_audio_backward(next_sample_to_read, samples_to_write, output);
      next_sample_to_read -= samples_to_write;
    }
  }
};
 
}