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/*
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/>.
*/
/**
* @file queues.h I/O
* @brief Queues macros and structures.
* @addtogroup IOQueues
* @{
*/
#ifndef _QUEUES_H_
#define _QUEUES_H_
/** Queue notification callback type. */
typedef void (*qnotify_t)(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
#if CH_USE_QUEUES
/**
* @brief Generic I/O queue structure.
* @details This structure represents a generic Input or Output asymmetrical
* queue. The queue is asymmetrical because one end is meant to be
* accessed from a thread context, and thus can be blocking, the other
* end is accessible from interrupt handlers or from within a kernel
* lock zone (see <b>I-Locked</b> and <b>S-Locked</b> states in
* @ref system_states) and is non-blocking.
*/
typedef struct {
uint8_t *q_buffer; /**< Pointer to the queue buffer.*/
uint8_t *q_top; /**< Pointer to the first location
after the buffer.*/
uint8_t *q_wrptr; /**< Write pointer.*/
uint8_t *q_rdptr; /**< Read pointer.*/
Semaphore q_sem; /**< Counter @p Semaphore.*/
qnotify_t q_notify; /**< Data notification callback.*/
} GenericQueue;
/** 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.
* @note The returned value can be less than zero when there are waiting
* threads on the internal semaphore.
*/
#define chQSpace(q) chSemGetCounterI(&(q)->q_sem)
/**
* @brief Input queue structure.
* @details This structure represents a generic asymmetrical input queue.
* Writing in the queue is non-blocking and can be performed from
* interrupt handlers or from within a kernel lock zone (see
* <b>I-Locked</b> and <b>S-Locked</b> states in @ref system_states).
* Reading the queue can be a blocking operation and is supposed to
* be performed by a system thread.
* @extends GenericQueue
*/
typedef GenericQueue InputQueue;
/** Evaluates to @p TRUE if the specified Input Queue is empty. */
#define chIQIsEmpty(q) (chQSpace(q) <= 0)
/** Evaluates to @p TRUE if the specified Input Queue is full. */
#define chIQIsFull(q) (chQSpace(q) >= chQSize(q))
/**
* @brief Input queue read.
* @details This function reads a byte value from an input queue. If the queue
* is empty then the calling thread is suspended until a byte arrives
* in the queue.
*
* @param[in] iqp pointer to an @p InputQueue structure
* @return A byte value from the queue or:
* @retval Q_RESET if the queue was reset.
*/
#define chIQGet(iqp) chIQGetTimeout(iqp, TIME_INFINITE)
/**
* @brief Data part of a static input queue initializer.
* @details This macro should be used when statically initializing an
* input queue that is part of a bigger structure.
* @param name the name of the input queue variable
* @param buffer pointer to the queue buffer area
* @param size size of the queue buffer area
* @param inotify input notification callback pointer
*/
#define _INPUTQUEUE_DATA(name, buffer, size, inotify) { \
buffer, \
buffer + size, \
buffer, \
buffer, \
_SEMAPHORE_DATA(name.q_sem, 0), \
inotify \
}
/**
* @brief Static input queue initializer.
* @details Statically initialized input queues require no explicit
* initialization using @p chIQInit().
* @param name the name of the input queue variable
* @param buffer pointer to the queue buffer area
* @param size size of the queue buffer area
* @param inotify input notification callback pointer
*/
#define INPUTQUEUE_DECL(name, buffer, size, inotify) \
InputQueue name = _INPUTQUEUE_DATA(name, buffer, size, inotify)
/**
* @brief Output queue structure.
* @details This structure represents a generic asymmetrical output queue.
* Reading from the queue is non-blocking and can be performed from
* interrupt handlers or from within a kernel lock zone (see
* <b>I-Locked</b> and <b>S-Locked</b> states in @ref system_states).
* Writing the queue can be a blocking operation and is supposed to
* be performed by a system thread.
* @extends GenericQueue
*/
typedef GenericQueue OutputQueue;
/** Evaluates to @p TRUE if the specified Output Queue is empty. */
#define chOQIsEmpty(q) (chQSpace(q) >= chQSize(q))
/** Evaluates to @p TRUE if the specified Output Queue is full. */
#define chOQIsFull(q) (chQSpace(q) <= 0)
/**
* @brief Output queue write.
* @details This function writes a byte value to an output queue. If the queue
* is full then the calling thread is suspended until there is space
* in the queue.
*
* @param[in] oqp pointer to an @p OutputQueue structure
* @param[in] b the byte value to be written in the queue
* @return The operation status:
* @retval Q_OK if the operation succeeded.
* @retval Q_RESET if the queue was reset.
*/
#define chOQPut(oqp, b) chOQPutTimeout(oqp, b, TIME_INFINITE)
/**
* @brief Data part of a static output queue initializer.
* @details This macro should be used when statically initializing an
* output queue that is part of a bigger structure.
* @param name the name of the output queue variable.
* @param buffer pointer to the queue buffer area
* @param size size of the queue buffer area
* @param onotify output notification callback pointer
*/
#define _OUTPUTQUEUE_DATA(name, buffer, size, onotify) { \
buffer, \
buffer + size, \
buffer, \
buffer, \
_SEMAPHORE_DATA(name.q_sem, size), \
onotify \
}
/**
* @brief Static output queue initializer.
* @details Statically initialized output queues require no explicit
* initialization using @p chOQInit().
* @param name the name of the output queue variable
* @param buffer pointer to the queue buffer area
* @param size size of the queue buffer area
* @param onotify output notification callback pointer
*/
#define OUTPUTQUEUE_DECL(name, buffer, size, onotify) \
InputQueue name = _OUTPUTQUEUE_DATA(name, buffer, size, onotify)
#ifdef __cplusplus
extern "C" {
#endif
void chIQInit(InputQueue *qp, uint8_t *buffer, size_t size, qnotify_t inotify);
void chIQResetI(InputQueue *qp);
msg_t chIQPutI(InputQueue *qp, uint8_t b);
msg_t chIQGetTimeout(InputQueue *qp, systime_t timeout);
size_t chIQRead(InputQueue *qp, uint8_t *buffer, size_t n);
void chOQInit(OutputQueue *queue, uint8_t *buffer, size_t size, qnotify_t onotify);
void chOQResetI(OutputQueue *queue);
msg_t chOQPutTimeout(OutputQueue *queue, uint8_t b, systime_t timeout);
msg_t chOQGetI(OutputQueue *queue);
size_t chOQWrite(OutputQueue *queue, uint8_t *buffer, size_t n);
#ifdef __cplusplus
}
#endif
#endif /* CH_USE_QUEUES */
#endif /* _QUEUES_H_ */
/** @} */
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