callback_timer_interrupt.h

 /******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2022 John Wellbelove
 
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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******************************************************************************/
 
#ifndef ETL_CALLBACK_TIMER_INTERRUPT_INCLUDED
#define ETL_CALLBACK_TIMER_INTERRUPT_INCLUDED
 
#include "platform.h"
#include "algorithm.h"
#include "nullptr.h"
#include "delegate.h"
#include "static_assert.h"
#include "timer.h"
#include "error_handler.h"
#include "placement_new.h"
 
#include <stdint.h>
 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  template <typename TInterruptGuard>
  class icallback_timer_interrupt
  {
  public:
 
    typedef etl::delegate<void(void)> callback_type;
 
    typedef etl::delegate<void(etl::timer::id::type)> event_callback_type;
 
    //*******************************************
    //*******************************************
    etl::timer::id::type register_timer(const callback_type& callback_,
                                        uint32_t             period_,
                                        bool                 repeating_)
    {
      etl::timer::id::type id = etl::timer::id::NO_TIMER;
 
      bool is_space = (number_of_registered_timers < Max_Timers);
 
      if (is_space)
      {
        // Search for the free space.
        for (uint_least8_t i = 0U; i < Max_Timers; ++i)
        {
          timer_data& timer = timer_array[i];
 
          if (timer.id == etl::timer::id::NO_TIMER)
          {
            TInterruptGuard guard;
            (void)guard; // Silence 'unused variable warnings.
 
            // Create in-place.
            new (&timer) timer_data(i, callback_, period_, repeating_);
            ++number_of_registered_timers;
            id = i;
            break;
          }
        }
      }
 
      return id;
    }
 
    //*******************************************
    //*******************************************
    bool unregister_timer(etl::timer::id::type id_)
    {
      bool result = false;
 
      if (id_ != etl::timer::id::NO_TIMER)
      {
        timer_data& timer = timer_array[id_];
 
        if (timer.id != etl::timer::id::NO_TIMER)
        {
          if (timer.is_active())
          {
            TInterruptGuard guard;
            (void)guard; // Silence 'unused variable warnings.
 
            active_list.remove(timer.id, false);
            remove_callback.call_if(timer.id);
          }
 
          // Reset in-place.
          new (&timer) timer_data();
          --number_of_registered_timers;
 
          result = true;
        }
      }
 
      return result;
    }
 
    //*******************************************
    //*******************************************
    void enable(bool state_)
    {
      enabled = state_;
    }
 
    //*******************************************
    //*******************************************
    bool is_running() const
    {
      return enabled;
    }
 
    //*******************************************
    //*******************************************
    void clear()
    {
      {
        TInterruptGuard guard;
        (void)guard; // Silence 'unused variable warnings.
 
        active_list.clear();
        number_of_registered_timers = 0;
      }
 
      for (uint8_t i = 0U; i < Max_Timers; ++i)
      {
        ::new (&timer_array[i]) timer_data();
      }
    }
 
    //*******************************************
    // Called by the timer service to indicate the
    // amount of time that has elapsed since the last successful call to 'tick'.
    // Returns true if the tick was processed,
    // false if not.
    //*******************************************
    bool tick(uint32_t count)
    {
      if (enabled)
      {
        // We have something to do?
        bool has_active = !active_list.empty();       
 
        if (has_active)
        {
          while (has_active && (count >= active_list.front().delta))
          {
            timer_data& timer = active_list.front();
 
            count -= timer.delta;
 
            active_list.remove(timer.id, true);
            remove_callback.call_if(timer.id);
 
            if (timer.callback.is_valid())
            {
              timer.callback();
            }
 
            if (timer.repeating)
            {
              // Reinsert the timer.
              timer.delta = timer.period;
              active_list.insert(timer.id);
              insert_callback.call_if(timer.id);
            }
 
            has_active = !active_list.empty();
          }
 
          if (has_active)
          {
            // Subtract any remainder from the next due timeout.
            active_list.front().delta -= count;
          }
        }
 
        return true;
      }
 
      return false;
    }
 
    //*******************************************
    //*******************************************
    bool start(etl::timer::id::type id_, bool immediate_ = false)
    {
      bool result = false;
 
      // Valid timer id?
      if (id_ != etl::timer::id::NO_TIMER)
      {
        timer_data& timer = timer_array[id_];
 
        // Registered timer?
        if (timer.id != etl::timer::id::NO_TIMER)
        {
          // Has a valid period.
          if (timer.period != etl::timer::state::Inactive)
          {
            TInterruptGuard guard;
            (void)guard; // Silence 'unused variable warnings.
 
            if (timer.is_active())
            {
              active_list.remove(timer.id, false);
              remove_callback.call_if(timer.id);
            }
 
            timer.delta = immediate_ ? 0U : timer.period;
            active_list.insert(timer.id);
            insert_callback.call_if(timer.id);
 
            result = true;
          }
        }
      }
 
      return result;
    }
 
    //*******************************************
    //*******************************************
    bool stop(etl::timer::id::type id_)
    {
      bool result = false;
 
      // Valid timer id?
      if (id_ != etl::timer::id::NO_TIMER)
      {
        timer_data& timer = timer_array[id_];
 
        // Registered timer?
        if (timer.id != etl::timer::id::NO_TIMER)
        {
          if (timer.is_active())
          {
            TInterruptGuard guard;
            (void)guard; // Silence 'unused variable warnings.
 
            active_list.remove(timer.id, false);
            remove_callback.call_if(timer.id);
          }
 
          result = true;
        }
      }
 
      return result;
    }
 
    //*******************************************
    //*******************************************
    bool set_period(etl::timer::id::type id_, uint32_t period_)
    {
      if (stop(id_))
      {
        timer_array[id_].period = period_;
        return true;
      }
 
      return false;
    }
 
    //*******************************************
    //*******************************************
    bool set_mode(etl::timer::id::type id_, bool repeating_)
    {
      if (stop(id_))
      {
        timer_array[id_].repeating = repeating_;
        return true;
      }
 
      return false;
    }
 
    //*******************************************
    //*******************************************
    bool has_active_timer() const
    {
      TInterruptGuard guard;
      (void)guard; // Silence 'unused variable warnings.
      return !active_list.empty();
    }
 
    //*******************************************
    //*******************************************
    uint32_t time_to_next() const
    {
      uint32_t delta = static_cast<uint32_t>(etl::timer::interval::No_Active_Interval);
 
      TInterruptGuard guard;
      (void)guard; // Silence 'unused variable warnings.
 
      if (!active_list.empty())
      {
        delta = active_list.front().delta;
      }
 
      return delta;
    }
 
    //*******************************************
    //*******************************************
    bool is_active(etl::timer::id::type id_) const
    {
      // Valid timer id?
      if (is_valid_timer_id(id_))
      {
        if (has_active_timer())
        {
          TInterruptGuard guard;
          (void)guard;  // Silence 'unused variable warnings.
 
          const timer_data& timer = timer_array[id_];
 
          // Registered timer?
          if (timer.id != etl::timer::id::NO_TIMER)
          {
            return timer.is_active();
          }
        }
      }
 
      return false;
    }
 
    //*******************************************
    //*******************************************
    void set_insert_callback(event_callback_type insert_)
    {
      insert_callback = insert_;
    }
 
    //*******************************************
    //*******************************************
    void set_remove_callback(event_callback_type remove_)
    {
      remove_callback = remove_;
    }
 
    //*******************************************
    void clear_insert_callback()
    {
      insert_callback.clear();
    }
 
    //*******************************************
    void clear_remove_callback()
    {
      remove_callback.clear();
    }
 
  protected:
 
    //*************************************************************************
    struct timer_data
    {
      //*******************************************
      timer_data()
        : callback()
        , period(0U)
        , delta(etl::timer::state::Inactive)
        , id(etl::timer::id::NO_TIMER)
        , previous(etl::timer::id::NO_TIMER)
        , next(etl::timer::id::NO_TIMER)
        , repeating(true)
      {
      }
 
      //*******************************************
      //*******************************************
      timer_data(etl::timer::id::type id_,
                 callback_type        callback_,
                 uint32_t             period_,
                 bool                 repeating_)
        : callback(callback_)
        , period(period_)
        , delta(etl::timer::state::Inactive)
        , id(id_)
        , previous(etl::timer::id::NO_TIMER)
        , next(etl::timer::id::NO_TIMER)
        , repeating(repeating_)
      {
      }
 
      //*******************************************
      //*******************************************
      bool is_active() const
      {
        return delta != etl::timer::state::Inactive;
      }
 
      //*******************************************
      //*******************************************
      void set_inactive()
      {
        delta = etl::timer::state::Inactive;
      }
 
      callback_type        callback;
      uint32_t             period;
      uint32_t             delta;
      etl::timer::id::type id;
      uint_least8_t        previous;
      uint_least8_t        next;
      bool                 repeating;
 
    private:
 
      // Disabled.
      timer_data(const timer_data& other) ETL_DELETE;
      timer_data& operator =(const timer_data& other) ETL_DELETE;
    };
 
    //*******************************************
    //*******************************************
    icallback_timer_interrupt(timer_data* const timer_array_, const uint_least8_t  Max_Timers_)
      : timer_array(timer_array_)
      , active_list(timer_array_)
      , enabled(false)
      , number_of_registered_timers(0U)
      , Max_Timers(Max_Timers_)
    {
    }
 
  private:
 
    //*******************************************
    //*******************************************
    bool is_valid_timer_id(etl::timer::id::type id_) const
    {
      return (id_ < Max_Timers);
    }
 
    //*************************************************************************
    //*************************************************************************
    class timer_list
    {
    public:
 
      //*******************************
      timer_list(timer_data* ptimers_)
        : head(etl::timer::id::NO_TIMER)
        , tail(etl::timer::id::NO_TIMER)
        , current(etl::timer::id::NO_TIMER)
        , ptimers(ptimers_)
      {
      }
 
      //*******************************
      bool empty() const
      {
        return head == etl::timer::id::NO_TIMER;
      }
 
      //*******************************
      // Inserts the timer at the correct delta position
      //*******************************
      void insert(etl::timer::id::type id_)
      {
        timer_data& timer = ptimers[id_];
 
        if (head == etl::timer::id::NO_TIMER)
        {
          // No entries yet.
          head = id_;
          tail = id_;
          timer.previous = etl::timer::id::NO_TIMER;
          timer.next = etl::timer::id::NO_TIMER;
        }
        else
        {
          // We already have entries.
          etl::timer::id::type test_id = begin();
 
          while (test_id != etl::timer::id::NO_TIMER)
          {
            timer_data& test = ptimers[test_id];
 
            // Find the correct place to insert.
            if (timer.delta <= test.delta)
            {
              if (test.id == head)
              {
                head = timer.id;
              }
 
              // Insert before test.
              timer.previous = test.previous;
              test.previous = timer.id;
              timer.next = test.id;
 
              // Adjust the next delta to compensate.
              test.delta -= timer.delta;
 
              if (timer.previous != etl::timer::id::NO_TIMER)
              {
                ptimers[timer.previous].next = timer.id;
              }
              break;
            }
            else
            {
              timer.delta -= test.delta;
            }
 
            test_id = next(test_id);
          }
 
          // Reached the end?
          if (test_id == etl::timer::id::NO_TIMER)
          {
            // Tag on to the tail.
            ptimers[tail].next = timer.id;
            timer.previous = tail;
            timer.next = etl::timer::id::NO_TIMER;
            tail = timer.id;
          }
        }
      }
 
      //*******************************
      void remove(etl::timer::id::type id_, bool has_expired)
      {
        timer_data& timer = ptimers[id_];
 
        if (head == id_)
        {
          head = timer.next;
        }
        else
        {
          ptimers[timer.previous].next = timer.next;
        }
 
        if (tail == id_)
        {
          tail = timer.previous;
        }
        else
        {
          ptimers[timer.next].previous = timer.previous;
        }
 
        if (!has_expired)
        {
          // Adjust the next delta.
          if (timer.next != etl::timer::id::NO_TIMER)
          {
            ptimers[timer.next].delta += timer.delta;
          }
        }
 
        timer.previous = etl::timer::id::NO_TIMER;
        timer.next     = etl::timer::id::NO_TIMER;
        timer.delta    = etl::timer::state::Inactive;
      }
 
      //*******************************
      timer_data& front()
      {
        return ptimers[head];
      }
 
      //*******************************
      const timer_data& front() const
      {
        return ptimers[head];
      }
 
      //*******************************
      etl::timer::id::type begin()
      {
        current = head;
        return current;
      }
 
      //*******************************
      etl::timer::id::type previous(etl::timer::id::type last)
      {
        current = ptimers[last].previous;
        return current;
      }
 
      //*******************************
      etl::timer::id::type next(etl::timer::id::type last)
      {
        current = ptimers[last].next;
        return current;
      }
 
      //*******************************
      void clear()
      {
        etl::timer::id::type id = begin();
 
        while (id != etl::timer::id::NO_TIMER)
        {
          timer_data& timer = ptimers[id];
          id = next(id);
          timer.next = etl::timer::id::NO_TIMER;
        }
 
        head    = etl::timer::id::NO_TIMER;
        tail    = etl::timer::id::NO_TIMER;
        current = etl::timer::id::NO_TIMER;
      }
 
    private:
 
      etl::timer::id::type head;
      etl::timer::id::type tail;
      etl::timer::id::type current;
 
      timer_data* const ptimers;
    };
 
    // The array of timer data structures.
    timer_data* const timer_array;
 
    // The list of active timers.
    timer_list active_list;
 
    bool enabled;
    uint_least8_t number_of_registered_timers;
 
    event_callback_type insert_callback;
    event_callback_type remove_callback;
 
  public:
 
    const uint_least8_t Max_Timers;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <uint_least8_t Max_Timers_, typename TInterruptGuard>
  class callback_timer_interrupt : public etl::icallback_timer_interrupt<TInterruptGuard>
  {
  public:
 
    ETL_STATIC_ASSERT(Max_Timers_ <= 254U, "No more than 254 timers are allowed");
 
    typedef typename icallback_timer_interrupt<TInterruptGuard>::callback_type callback_type;
 
    //*******************************************
    //*******************************************
    callback_timer_interrupt()
      : icallback_timer_interrupt<TInterruptGuard>(timer_array, Max_Timers_)
    {
    }
 
  private:
 
    typename icallback_timer_interrupt<TInterruptGuard>::timer_data timer_array[Max_Timers_];
  };
}
 
#endif