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Diffstat (limited to 'libs/backends/portaudio/cycle_timer.h')
| -rw-r--r-- | libs/backends/portaudio/cycle_timer.h | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/libs/backends/portaudio/cycle_timer.h b/libs/backends/portaudio/cycle_timer.h new file mode 100644 index 0000000000..95811ae1ca --- /dev/null +++ b/libs/backends/portaudio/cycle_timer.h @@ -0,0 +1,103 @@ +/* + * 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 (uint64_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 ()); + } + + uint64_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 (uint64_t timer_value_us) const + { return (timer_value_us >= get_start()) && (timer_value_us < get_next_start()); + } + + void reset_start (uint64_t timestamp) { m_cycle_start = timestamp; } + + uint64_t get_start () const { return m_cycle_start; } + + uint64_t microseconds_since_start (uint64_t timestamp) const + { + return timestamp - m_cycle_start; + } + + uint64_t microseconds_since_start (uint32_t samples) const + { + return m_cycle_start + samples * get_sample_length_us (); + } + + uint64_t get_next_start () const + { + return m_cycle_start + rint (get_length_us ()); + } + +private: + uint64_t m_cycle_start; + + uint32_t m_samplerate; + uint32_t m_samples_per_cycle; +}; + +#endif // CYCLE_TIMER_H |