110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
/**
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* \file
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*
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* \brief Ringbuffer functionality implementation.
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*
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* Copyright (c) 2014-2018 Microchip Technology Inc. and its subsidiaries.
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*
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* \asf_license_start
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*
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* \page License
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*
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* Subject to your compliance with these terms, you may use Microchip
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* software and any derivatives exclusively with Microchip products.
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* It is your responsibility to comply with third party license terms applicable
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* to your use of third party software (including open source software) that
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* may accompany Microchip software.
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*
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* THIS SOFTWARE IS SUPPLIED BY MICROCHIP "AS IS". NO WARRANTIES,
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* WHETHER EXPRESS, IMPLIED OR STATUTORY, APPLY TO THIS SOFTWARE,
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* INCLUDING ANY IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY,
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* AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL MICROCHIP BE
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* LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE, INCIDENTAL OR CONSEQUENTIAL
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* LOSS, DAMAGE, COST OR EXPENSE OF ANY KIND WHATSOEVER RELATED TO THE
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* SOFTWARE, HOWEVER CAUSED, EVEN IF MICROCHIP HAS BEEN ADVISED OF THE
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* POSSIBILITY OR THE DAMAGES ARE FORESEEABLE. TO THE FULLEST EXTENT
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* ALLOWED BY LAW, MICROCHIP'S TOTAL LIABILITY ON ALL CLAIMS IN ANY WAY
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* RELATED TO THIS SOFTWARE WILL NOT EXCEED THE AMOUNT OF FEES, IF ANY,
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* THAT YOU HAVE PAID DIRECTLY TO MICROCHIP FOR THIS SOFTWARE.
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*
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* \asf_license_stop
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*
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*/
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#include <errno.h>
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#include "utils_ringbuffer.h"
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/**
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* \brief Ringbuffer init
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*/
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int32_t ringbuffer_init(struct ringbuffer *const rb, void *buf, uint32_t size)
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{
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/*
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* buf size must be aligned to power of 2
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*/
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if ((size & (size - 1)) != 0) {
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return -EINVAL;
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}
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/* size - 1 is faster in calculation */
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rb->size = size - 1;
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rb->read_index = 0;
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rb->write_index = rb->read_index;
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rb->buf = (uint8_t *)buf;
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return 0;
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}
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/**
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* \brief Get one byte from ringbuffer
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*
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*/
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int32_t ringbuffer_get(struct ringbuffer *const rb, uint8_t *data)
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{
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if (rb->write_index != rb->read_index) {
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*data = rb->buf[rb->read_index & rb->size];
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rb->read_index++;
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return 0;
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}
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return -ENOENT;
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}
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/**
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* \brief Put one byte to ringbuffer
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*
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*/
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int32_t ringbuffer_put(struct ringbuffer *const rb, uint8_t data)
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{
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rb->buf[rb->write_index & rb->size] = data;
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/*
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* buffer full strategy: new data will overwrite the oldest data in
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* the buffer
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*/
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if ((rb->write_index - rb->read_index) > rb->size) {
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rb->read_index = rb->write_index - rb->size;
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}
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rb->write_index++;
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return 0;
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}
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/**
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* \brief Return the element number of ringbuffer
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*/
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uint32_t ringbuffer_num(const struct ringbuffer *const rb)
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{
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return rb->write_index - rb->read_index;
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}
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/**
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* \brief Flush ringbuffer
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*/
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uint32_t ringbuffer_flush(struct ringbuffer *const rb)
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{
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rb->read_index = rb->write_index;
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return 0;
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}
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