Channel.h

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#ifndef SCHEDULER_CHANNEL_H
#define SCHEDULER_CHANNEL_H

#include <Scheduler.h>

class Channel {
public:
 Channel() :
   m_buf(NULL),
   m_max(0),
   m_size(0),
   m_ticket(0),
   m_serving(0)
  {}

  int send(const void* buf, size_t size)
  {
    // Take a ticket and wait for service
    uint8_t ticket = m_ticket++;
    await(ticket == m_serving && m_buf != NULL);

    // Check that the receiver buffer can hold the message
    if (size > m_max) {
      m_serving += 1;
      return (-1);
    }

    // Copy message to receiver buffer
    memcpy(m_buf, buf, size);
    m_size = size;
    return (size);
  }

  int recv(void* buf, size_t size)
  {
    // Wait for the channel to be free for receive
    await(m_buf == NULL);
    m_buf = buf;
    m_max = size;
    m_size = 0;

    // Wait for message from sender
    await(m_size != 0);
    int res = m_size;
    m_buf = NULL;
    m_max = 0;
    m_size = 0;
    m_serving += 1;

    // Return size of received message
    return (res);
  }

protected:
  void* m_buf;                  
  volatile size_t m_max;        
  volatile size_t m_size;       
  volatile uint8_t m_ticket;    
  volatile uint8_t m_serving;   
};

#endif