ChibiOS/src/include/queues.h

/*
    ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT 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, see <http://www.gnu.org/licenses/>.
*/

/**
 * @addtogroup IOQueues
 * @{
 */

#ifndef _QUEUES_H_
#define _QUEUES_H_

/** Queue notification callback type.*/
typedef void (*t_qnotify)(void);

/** Returned by the queue functions if the operation is successful.*/
#define Q_OK        RDY_OK
/** Returned by the queue functions if a timeout occurs.*/
#define Q_TIMEOUT   RDY_TIMEOUT
/** Returned by the queue functions if the queue is reset.*/
#define Q_RESET     RDY_RESET
/** Returned by the queue functions if the queue is empty.*/
#define Q_EMPTY     -3
/** Returned by the queue functions if the queue is full.*/
#define Q_FULL      -4

#ifdef CH_USE_QUEUES
/**
 * I/O queue structure, it is used by both Input and Output Queues,
 * the difference is on how the semaphore is initialized.
 */
typedef struct {
  /** Pointer to the queue buffer.*/
  BYTE8             *q_buffer;
  /** Pointer to the first location after the buffer.*/
  BYTE8             *q_top;
  /** Write pointer.*/
  BYTE8             *q_wrptr;
  /** Read pointer.*/
  BYTE8             *q_rdptr;
  /** Counter semaphore.*/
  Semaphore         q_sem;
  /** Data notification callback.*/
  t_qnotify         q_notify;
} Queue;

/** Returns the queue's buffer size.*/
#define chQSize(q) \
        ((q)->q_top - (q)->q_buffer)

/** Returns the used space if used on an Input Queue and the empty space if
 *  used on an Output Queue.*/
#define chQSpace(q) \
        ((q)->q_sem.s_cnt)

/** Evaluates to TRUE if the specified Input Queue is empty.*/
#define chIQIsEmpty(q) \
        (chQSpace(q) <= 0)

/** Evaluates to TRUE if the specified Input Queue is full.*/
#define chIQIsFull(q) \
        (chQSpace(q) >= chQSize(q))

/** Evaluates to TRUE if the specified Output Queue is empty.*/
#define chOQIsEmpty(q) \
        (chQSpace(q) >= chQSize(q))

/** Evaluates to TRUE if the specified Output Queue is full.*/
#define chOQIsFull(q) \
        (chQSpace(q) <= 0)

#ifdef __cplusplus
extern "C" {
#endif
  /*
   * Input Queues functions. An Input Queue is usually written into by an
   * interrupt handler and read from a thread.
   */
  void chIQInit(Queue *qp, BYTE8 *buffer, t_size size, t_qnotify inotify);
  void chIQReset(Queue *qp);
  t_msg chIQPutI(Queue *qp, BYTE8 b);
  t_msg chIQGet(Queue *qp);
  t_size chIQRead(Queue *qp, BYTE8 *buffer, t_size n);
#ifdef CH_USE_QUEUES_TIMEOUT
  t_msg chIQGetTimeout(Queue *qp, t_time time);
#endif

  /*
   * Output Queues functions. An Output Queue is usually written into by a
   * thread and read from an interrupt handler.
   */
  void chOQInit(Queue *queue, BYTE8 *buffer, t_size size, t_qnotify onotify);
  void chOQReset(Queue *queue);
  void chOQPut(Queue *queue, BYTE8 b);
  t_msg chOQGetI(Queue *queue);
  t_size chOQWrite(Queue *queue, BYTE8 *buffer, t_size n);
#ifdef __cplusplus
}
#endif
#endif  /* CH_USE_QUEUES */

#ifdef CH_USE_QUEUES_HALFDUPLEX
/**
 * Half duplex queue structure.
 */
typedef struct {
  /** Pointer to the queue buffer.*/
  BYTE8             *hdq_buffer;
  /** Pointer to the first location after the buffer.*/
  BYTE8             *hdq_top;
  /** Write pointer.*/
  BYTE8             *hdq_wrptr;
  /** Read pointer.*/
  BYTE8             *hdq_rdptr;
  /** Input counter semaphore.*/
  Semaphore         hdq_isem;
  /** Output counter semaphore.*/
  Semaphore         hdq_osem;
  /** Input data notification callback.*/
  t_qnotify         hdq_inotify;
  /** Output data notification callback.*/
  t_qnotify         hdq_onotify;
} HalfDuplexQueue;

/** Returns the queue's buffer size.*/
#define chHDQSize(q) \
        ((q)->hdq_top - (q)->hdq_buffer)

/** Returns the queue space when in transmission mode.*/
#define chHDQEmptySpace(q) \
        ((q)->hdq_osem.s_cnt)

/** Returns the number of the bytes in the queue when in receive mode.*/
#define chHDQFilledSpace(q) \
        ((q)->hdq_isem.s_cnt)

/** Evaluates to TRUE if the queue is in transmit mode.*/
#define chHDQIsTransmitting(q) \
        (chHDQEmptySpace(q) < chHDQSize(q))

/** Evaluates to TRUE if the queue is in receive mode.*/
#define chHDQIsReceiving(q) \
        (chHDQEmptySpaceQ(q) >= chHDQSize(q))

/** Evaluates to TRUE if the receive queue is full.*/
#define chHDQIsFullReceive(q) \
        (chHDQFilledSpace(q) >= chHDQSize(q))

#ifdef __cplusplus
extern "C" {
#endif
  void chHDQInit(HalfDuplexQueue *qp, BYTE8 *buffer, t_size size,
                 t_qnotify inotify, t_qnotify onotify);
  t_msg chHDQGetReceive(HalfDuplexQueue *qp);
  void chHDQPutTransmit(HalfDuplexQueue *qp, BYTE8 b);
  t_msg chHDQGetTransmitI(HalfDuplexQueue *qp);
  t_msg chHDQPutReceiveI(HalfDuplexQueue *qp, BYTE8 b);
#ifdef CH_USE_QUEUES_TIMEOUT
  t_msg chHDQGetReceiveTimeout(HalfDuplexQueue *qp, t_time time);
#endif
#ifdef __cplusplus
}
#endif

#endif /* CH_USE_QUEUES_HALFDUPLEX */

#endif /* _QUEUES_H_ */

/** @} */