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livetrax/libs/backends/portaudio/cycle_timer.h

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/*
* Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef CYCLE_TIMER_H
#define CYCLE_TIMER_H
#include <stdint.h>
#include <cmath>
#include <algorithm>
// Could call it FrameTimer and make it more generic
// Could be an interface and or include clock source
// include sample count/processed frames in iteration?
class CycleTimer {
public:
CycleTimer ()
: m_cycle_start (0)
, m_samplerate (0)
, m_samples_per_cycle (0)
{
}
void set_samplerate (double samplerate) { m_samplerate = samplerate; }
double get_samplerate () const { return m_samplerate; }
double get_sample_length_us () const { return 1e6 / m_samplerate; }
double get_length_us () const
{
return get_sample_length_us () * m_samples_per_cycle;
}
void set_samples_per_cycle (uint32_t samples)
{
m_samples_per_cycle = samples;
}
uint32_t get_samples_per_cycle () const { return m_samples_per_cycle; }
// rint?? that may round to sample outside of cycle?
// max(0, value)?
uint32_t samples_since_cycle_start (int64_t timer_val) const
{
if (timer_val < m_cycle_start) {
return 0;
}
return std::max((double)0, (timer_val - get_start ()) / get_sample_length_us ());
}
int64_t timestamp_from_sample_offset (uint32_t sample_offset)
{
return m_cycle_start + get_sample_length_us () * sample_offset;
}
bool valid () const { return m_samples_per_cycle && m_samplerate; }
bool in_cycle(int64_t timer_value_us) const
{
return (timer_value_us >= get_start()) && (timer_value_us < get_next_start());
}
void reset_start (int64_t timestamp) { m_cycle_start = timestamp; }
int64_t get_start () const { return m_cycle_start; }
int64_t microseconds_since_start (int64_t timestamp) const
{
return timestamp - m_cycle_start;
}
int64_t microseconds_since_start (uint32_t samples) const
{
return m_cycle_start + samples * get_sample_length_us ();
}
int64_t get_next_start () const
{
return m_cycle_start + rint (get_length_us ());
}
private:
int64_t m_cycle_start;
uint32_t m_samplerate;
uint32_t m_samples_per_cycle;
};
#endif // CYCLE_TIMER_H