pointer_policy.h

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/******************************************************************************
 Copyright (c) 2012-2016 Institut für Nachrichtentechnik, Universität Rostock
 Copyright (c) 2006-2012 Quality & Usability Lab
                         Deutsche Telekom Laboratories, TU Berlin
 
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// https://AudioProcessingFramework.github.io/
 
 
#ifndef APF_POINTER_POLICY_H
#define APF_POINTER_POLICY_H
 
#include <cassert>  // for assert()
#include "apf/parameter_map.h"
#include "apf/iterator.h"  // for has_begin_and_end
 
#ifndef APF_MIMOPROCESSOR_SAMPLE_TYPE
#define APF_MIMOPROCESSOR_SAMPLE_TYPE float
#endif
#ifndef APF_MIMOPROCESSOR_INTERFACE_POLICY
#define APF_MIMOPROCESSOR_INTERFACE_POLICY apf::pointer_policy<APF_MIMOPROCESSOR_SAMPLE_TYPE*>
#endif
 
namespace apf
{
 
template<typename T> class pointer_policy;  // no implementation, use <T*>!
 
template<typename T>
class pointer_policy<T*>
{
  public:
    using sample_type = T;
 
    class Input;
    class Output;
 
    void audio_callback(size_t n, T* const* in, T* const* out);
 
    // for now, do nothing:
    bool activate() const { return true; }
    bool deactivate() const { return true; }
 
    size_t block_size() const { return _block_size; }
    size_t sample_rate() const { return _sample_rate; }
 
    int in_channels() const { return _next_input_id; }
    int out_channels() const { return _next_output_id; }
 
  protected:
    explicit pointer_policy(const parameter_map& params = parameter_map())
      : _sample_rate(params.get<size_t>("sample_rate"))
      , _block_size(params.get<size_t>("block_size"))
      , _next_input_id(0)
      , _next_output_id(0)
      , _in(0)
      , _out(0)
    {}
 
    virtual ~pointer_policy() = default;
 
  private:
    virtual void process() = 0;
 
    int get_next_input_id() { return _next_input_id++; }
 
    int get_next_output_id() { return _next_output_id++; }
 
    const size_t _sample_rate;
    const size_t _block_size;
 
    int _next_input_id;
    int _next_output_id;
    T* const* _in;
    T* const* _out;
};
 
template<typename T>
void
pointer_policy<T*>::audio_callback(size_t n, T* const* in, T* const* out)
{
  assert(n == this->block_size());
  (void)n;  // avoid "unused parameter" warning
 
  _in = in;
  _out = out;
  this->process();
}
 
template<typename T>
class pointer_policy<T*>::Input
{
  public:
    using iterator = T const*;
 
    struct buffer_type : has_begin_and_end<iterator> { friend class Input; };
 
    void fetch_buffer()
    {
      this->buffer._begin = _parent._in[_id];
      this->buffer._end   = this->buffer._begin + _parent.block_size();
    }
 
    buffer_type buffer;
 
  protected:
    Input(pointer_policy& parent, const parameter_map&)
      : _parent(parent)
      , _id(_parent.get_next_input_id())
    {}
 
    ~Input() = default;
 
  private:
    Input(const Input&); Input& operator=(const Input&);  // deactivated
 
    pointer_policy& _parent;
    const int _id;
};
 
template<typename T>
class pointer_policy<T*>::Output
{
  public:
    using iterator = T*;
 
    struct buffer_type : has_begin_and_end<iterator> { friend class Output; };
 
    void fetch_buffer()
    {
      this->buffer._begin = _parent._out[_id];
      this->buffer._end   = this->buffer._begin + _parent.block_size();
    }
 
    buffer_type buffer;
 
  protected:
    Output(pointer_policy& parent, const parameter_map&)
      : _parent(parent)
      , _id(_parent.get_next_output_id())
    {}
 
    ~Output() = default;
 
  private:
    Output(const Output&); Output& operator=(const Output&);  // deactivated
 
    pointer_policy& _parent;
    const int _id;
};
 
}  // namespace apf
 
#endif