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/*
ChibiOS - Copyright (C) 2006..2015 Giovanni Di Sirio
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/**
* @file hal_buffers.c
* @brief I/O Buffers code.
*
* @addtogroup HAL_BUFFERS
* @{
*/
#include "hal.h"
/*===========================================================================*/
/* Driver local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local variables and types. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Initializes an input double buffer object.
*
* @param[out] ibqp pointer to the @p io_buffers_queue_t object
* @param[in] bp pointer to a memory area allocated for buffers
* @param[in] size buffer size, including the size field which is the
* size of a @p size_t
* @param[in] n number of buffers
* @param[in] infy callback called when a buffer is returned to the queue
* @param[in] link application defined pointer
*
* @init
*/
void ibqObjectInit(input_buffers_queue_t *ibqp, uint8_t *bp,
size_t size, size_t n,
dbnotify_t infy, void *link) {
osalDbgCheck((ibqp != NULL) && (bp != NULL) && (size >= sizeof(size_t) + 2));
ibqp->bcounter = 0;
ibqp->brdptr = bp;
ibqp->bwrptr = bp;
ibqp->btop = bp + (size * n); /* Pre-calculated for speed. */
ibqp->bsize = size;
ibqp->bn = n;
ibqp->buffers = bp;
ibqp->ptr = NULL;
ibqp->top = NULL;
ibqp->notify = infy;
ibqp->link = link;
}
/**
* @brief Gets the next empty buffer from the queue.
* @note The function always returns the same buffer if called repeatedly.
*
* @param[out] ibqp pointer to the @p input_buffers_queue_t object
* @return A pointer to the next buffer to be filled.
* @retval NULL if the queue is full.
*
* @iclass
*/
uint8_t *ibqGetEmptyBufferI(input_buffers_queue_t *ibqp) {
osalDbgCheckClassI();
if (ibqIsFullI(ibqp)) {
return NULL;
}
return ibqp->bwrptr + sizeof (size_t);
}
/**
* @brief Posts a new filled buffer in the queue.
*
* @param[out] ibqp pointer to the @p input_buffers_queue_t object
* @param[in] size used size of the buffer
*
* @iclass
*/
void ibqPostBufferI(io_buffers_queue_t *ibqp, size_t size) {
osalDbgCheckClassI();
osalDbgAssert(!ibqIsFullI(ibqp), "buffers queue full");
/* Writing size field in the buffer.*/
*((size_t *)ibqp->bwrptr) = size;
/* Posting the buffer in the queue.*/
ibqp->bcounter++;
ibqp->bwrptr += ibqp->bsize;
if (ibqp->bwrptr >= ibqp->btop) {
ibqp->bwrptr = ibqp->buffers;
}
/* Waking up one waiting thread, if any.*/
osalThreadDequeueNextI(&ibqp->waiting, MSG_OK);
}
/**
* @brief Gets the next filled buffer from the queue.
* @note The function always returns the same buffer if called repeatedly.
* @post After calling the function the fields @p ptr and @p top are set
* at beginning and end of the buffer data or @NULL if the queue
* is empty.
*
* @param[out] ibqp pointer to the @p input_buffers_queue_t object
* @return A pointer to filled buffer area.
* @retval NULL if the queue is empty.
*
* @iclass
*/
uint8_t *ibqGetFullBufferI(input_buffers_queue_t *ibqp) {
osalDbgCheckClassI();
if (ibqIsEmptyI(ibqp)) {
ibqp->ptr = NULL;
ibqp->top = NULL;
return NULL;
}
ibqp->ptr = ibqp->brdptr + sizeof (size_t);
ibqp->top = ibqp->ptr + *((size_t *)ibqp->brdptr);
return ibqp->brdptr;
}
/**
* @brief Releases the next filled buffer back in the queue.
*
* @param[out] ibqp pointer to the @p input_buffers_queue_t object
*
* @iclass
*/
void ibqReleaseBufferI(io_buffers_queue_t *ibqp) {
osalDbgCheckClassI();
osalDbgAssert(!ibqIsEmptyI(ibqp), "buffers queue empty");
/* Freeing a buffer slot in the queue.*/
ibqp->bcounter--;
ibqp->brdptr += ibqp->bsize;
if (ibqp->brdptr >= ibqp->btop) {
ibqp->brdptr = ibqp->buffers;
}
/* Notifying the buffer release.*/
if (ibqp->notify != NULL) {
ibqp->notify(ibqp);
}
}
/**
* @brief Input queue read with timeout.
* @details This function reads a byte value from an input queue. If
* the queue is empty then the calling thread is suspended until a
* new buffer arrives in the queue or a timeout occurs.
* @note The callback is invoked before reading the character from the
* buffer or before entering the suspended state.
*
* @param[in] ibqp pointer to the @p input_buffers_queue_t object
* @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 A byte value from the queue.
* @retval MSG_TIMEOUT if the specified time expired.
* @retval MSG_RESET if the queue has been reset.
*
* @api
*/
msg_t ibqGetTimeout(input_buffers_queue_t *ibqp, systime_t timeout) {
msg_t msg;
/* This condition indicates that a new buffer must be acquired.*/
while (ibqp->ptr == NULL) {
msg = osalThreadEnqueueTimeoutS(&ibqp->waiting, timeout);
if (msg < MSG_OK) {
return msg;
}
(void) ibqGetFullBufferI(ibqp);
}
/* Next byte from the buffer.*/
msg = *ibqp->ptr;
ibqp->ptr++;
/* If the current buffer has been fully read then it is returned as
empty in the queue.*/
if (ibqp->ptr == ibqp->top) {
ibqReleaseBufferI(ibqp);
ibqp->ptr = NULL;
}
return msg;
}
/**
* @brief Input queue read with timeout.
* @details The function reads data from an input queue into a buffer.
* The operation completes when the specified amount of data has been
* transferred or after the specified timeout or if the queue has
* been reset.
* @note The function is not atomic, if you need atomicity it is suggested
* to use a semaphore or a mutex for mutual exclusion.
* @note The callback is invoked before reading each character from the
* buffer or before entering the state @p THD_STATE_WTQUEUE.
*
* @param[in] ibqp pointer to the @p input_buffers_queue_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.
*
* @api
*/
size_t ibqReadTimeout(input_buffers_queue_t *ibqp, uint8_t *bp,
size_t n, systime_t timeout) {
}
/** @} */
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