/*
ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
This file is part of ChibiOS.
ChibiOS 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 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 .
*/
/**
* @file chpipes.c
* @brief Pipes code.
* @details Byte pipes.
* Operation mode
* A pipe is an asynchronous communication mechanism.
* Operations defined for mailboxes:
* - Write: Writes a buffer of data in the pipe in FIFO order.
* - Read: A buffer of data is read from the read and removed.
* - Reset: The pipe is emptied and all the stored data
* is lost.
* .
* @pre In order to use the pipes APIs the @p CH_CFG_USE_PIPES
* option must be enabled in @p chconf.h.
* @note Compatible with RT and NIL.
*
* @addtogroup oslib_pipes
* @{
*/
#include "ch.h"
#if (CH_CFG_USE_PIPES == TRUE) || defined(__DOXYGEN__)
/*===========================================================================*/
/* Module local definitions. */
/*===========================================================================*/
/*
* Defaults on the best synchronization mechanism available.
*/
#if (CH_CFG_USE_MUTEXES == TRUE) || defined(__DOXYGEN__)
#define P_LOCK(p) chMtxLock(&(p)->mtx)
#define P_UNLOCK(p) chMtxUnlock(&(p)->mtx)
#else
#define P_LOCK(p) (void) chSemWait(&(p)->sem)
#define P_UNLOCK(p) chSemSignal(&(p)->sem)
#endif
/*===========================================================================*/
/* Module exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported functions. */
/*===========================================================================*/
/**
* @brief Initializes a @p mailbox_t object.
*
* @param[out] pp the pointer to the @p pipe_t structure to be
* initialized
* @param[in] buf pointer to the pipe buffer as an array of @p uint8_t
* @param[in] n number of elements in the buffer array
*
* @init
*/
void chPipeObjectInit(pipe_t *pp, uint8_t *buf, size_t n) {
chDbgCheck((pp != NULL) && (buf != NULL) && (n > (size_t)0));
pp->buffer = buf;
pp->rdptr = buf;
pp->wrptr = buf;
pp->top = &buf[n];
pp->cnt = (size_t)0;
pp->reset = false;
chThdQueueObjectInit(&pp->qw);
chThdQueueObjectInit(&pp->qr);
}
/**
* @brief Resets a @p pipe_t object.
* @details All the waiting threads are resumed with status @p MSG_RESET and
* the queued data is lost.
* @post The pipe is in reset state, all operations will fail and
* return @p MSG_RESET until the mailbox is enabled again using
* @p chPipeResumeX().
*
* @param[in] pp the pointer to an initialized @p pipe_t object
*
* @api
*/
void chPipeReset(pipe_t *pp) {
chDbgCheck(pp != NULL);
P_LOCK(pp);
chSysLock();
pipe_t->wrptr = pipe_t->buffer;
pipe_t->rdptr = pipe_t->buffer;
pipe_t->cnt = (size_t)0;
pipe_t->reset = true;
chThdDequeueAllI(&pipe_t->qw, MSG_RESET);
chThdDequeueAllI(&pipe_t->qr, MSG_RESET);
chSchRescheduleS();
chSysUnlock();
P_UNLOCK();
}
/**
* @brief Pipe write with timeout.
* @details The function writes data from a buffer to a pipe. The
* operation completes when the specified amount of data has been
* transferred or after the specified timeout or if the pipe has
* been reset.
*
* @param[in] pp the pointer to an initialized @p pipe_t object
* @param[in] bp pointer to the data buffer
* @param[in] n the maximum amount of data to be transferred, the
* value 0 is reserved
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The number of bytes effectively transferred.
* @retval MSG_RESET if the mailbox has been reset.
* @retval MSG_TIMEOUT if the operation has timed out.
*
* @api
*/
size_t chPipeWriteTimeout(pipe_t *pp, const uint8_t *bp,
size_t n, sysinterval_t timeout) {
}
/**
* @brief Pipe read with timeout.
* @details The function reads data from a pipe into a buffer. The
* operation completes when the specified amount of data has been
* transferred or after the specified timeout or if the pipe has
* been reset.
*
* @param[in] pp the pointer to an initialized @p pipe_t object
* @param[out] bp pointer to the data buffer
* @param[in] n the maximum amount of data to be transferred, the
* value 0 is reserved
* @param[in] timeout the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The number of bytes effectively transferred.
* @retval MSG_RESET if the mailbox has been reset.
* @retval MSG_TIMEOUT if the operation has timed out.
*
* @api
*/
size_t chPipeReadTimeout(pipe_t *pp, uint8_t *bp,
size_t n, sysinterval_t timeout) {
}
#endif /* CH_CFG_USE_MAILBOXES == TRUE */
/** @} */
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