skarg
445 lines
14 KiB
C
445 lines
14 KiB
C
/*####COPYRIGHTBEGIN####
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-------------------------------------------
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Copyright (C) 2008 by Steve Karg
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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The Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307
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USA.
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As a special exception, if other files instantiate templates or
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use macros or inline functions from this file, or you compile
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this file and link it with other works to produce a work based
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on this file, this file does not by itself cause the resulting
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work to be covered by the GNU General Public License. However
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the source code for this file must still be made available in
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accordance with section (3) of the GNU General Public License.
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This exception does not invalidate any other reasons why a work
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based on this file might be covered by the GNU General Public
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License.
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-------------------------------------------
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####COPYRIGHTEND####*/
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/* Functional Description: Generic ring buffer library for deeply
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embedded system. See the unit tests for usage examples. */
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#include <stddef.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include "ringbuf.h"
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/****************************************************************************
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* DESCRIPTION: Returns the number of elements in the ring buffer
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* RETURN: Number of elements in the ring buffer
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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unsigned Ringbuf_Count(
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RING_BUFFER const *b)
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{
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unsigned head, tail; /* used to avoid volatile decision */
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if (b) {
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head = b->head;
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tail = b->tail;
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return head - tail;
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}
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return 0;
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}
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/****************************************************************************
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* DESCRIPTION: Returns the empty/full status of the ring buffer
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* RETURN: true if the ring buffer is full, false if it is not.
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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bool Ringbuf_Full(
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RING_BUFFER const *b)
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{
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return (b ? (Ringbuf_Count(b) == b->element_count) : true);
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}
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/****************************************************************************
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* DESCRIPTION: Returns the empty/full status of the ring buffer
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* RETURN: true if the ring buffer is empty, false if it is not.
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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bool Ringbuf_Empty(
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RING_BUFFER const *b)
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{
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return (b ? (Ringbuf_Count(b) == 0) : true);
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}
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/****************************************************************************
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* DESCRIPTION: Looks at the data from the front of the list without removing it
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* RETURN: pointer to the data, or NULL if nothing in the list
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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volatile uint8_t *Ringbuf_Peek(
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RING_BUFFER const *b)
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{
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volatile uint8_t *data_element = NULL; /* return value */
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if (!Ringbuf_Empty(b)) {
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data_element = b->buffer;
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data_element += ((b->tail % b->element_count) * b->element_size);
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}
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return data_element;
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}
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/****************************************************************************
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* DESCRIPTION: Copy the data from the front of the list, and removes it
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* RETURN: true if data was copied, false if list is empty
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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bool Ringbuf_Pop(
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RING_BUFFER * b,
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uint8_t * data_element)
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{
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bool status = false; /* return value */
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volatile uint8_t *ring_data = NULL; /* used to help point ring data */
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unsigned i; /* loop counter */
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if (!Ringbuf_Empty(b)) {
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ring_data = b->buffer;
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ring_data += ((b->tail % b->element_count) * b->element_size);
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if (data_element) {
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for (i = 0; i < b->element_size; i++) {
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data_element[i] = ring_data[i];
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}
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}
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b->tail++;
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status = true;
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}
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return status;
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}
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/****************************************************************************
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* DESCRIPTION: Adds an element of data to the end of the ring buffer
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* RETURN: true on succesful add, false if not added
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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bool Ringbuf_Put(
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RING_BUFFER * b, /* ring buffer structure */
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uint8_t * data_element)
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{ /* one element to add to the ring */
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bool status = false; /* return value */
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volatile uint8_t *ring_data = NULL; /* used to help point ring data */
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unsigned i; /* loop counter */
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if (b && data_element) {
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/* limit the amount of elements that we accept */
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if (!Ringbuf_Full(b)) {
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ring_data = b->buffer;
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ring_data += ((b->head % b->element_count) * b->element_size);
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for (i = 0; i < b->element_size; i++) {
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ring_data[i] = data_element[i];
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}
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b->head++;
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status = true;
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}
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}
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return status;
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}
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/****************************************************************************
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* DESCRIPTION: Adds an element of data to the front of the ring buffer
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* RETURN: true on succesful add, false if not added
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* ALGORITHM: none
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* NOTES: moves the tail on add instead of head, so this function
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* can't be used if keeping producer and consumer
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* as separate processes (i.e. interrupts)
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*****************************************************************************/
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bool Ringbuf_Put_Front(
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RING_BUFFER * b, /* ring buffer structure */
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uint8_t * data_element)
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{ /* one element to add to the front of the ring */
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bool status = false; /* return value */
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volatile uint8_t *ring_data = NULL; /* used to help point ring data */
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unsigned i = 0; /* loop counter */
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if (b && data_element) {
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/* limit the amount of elements that we accept */
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if (!Ringbuf_Full(b)) {
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b->tail--;
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ring_data = b->buffer;
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ring_data += ((b->tail % b->element_count) * b->element_size);
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/* copy the data to the ring data element */
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for (i = 0; i < b->element_size; i++) {
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ring_data[i] = data_element[i];
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}
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status = true;
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}
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}
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return status;
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}
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/****************************************************************************
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* DESCRIPTION: Gets a pointer to the next free data element of the buffer
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* without adding it to the ring.
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* RETURN: pointer to the next data chunk, or NULL if ring buffer is full.
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* ALGORITHM: none
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* NOTES: Use Ringbuf_Data_Peek with Ringbuf_Data_Put
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*****************************************************************************/
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volatile uint8_t *Ringbuf_Data_Peek(RING_BUFFER * b)
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{
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volatile uint8_t *ring_data = NULL; /* used to help point ring data */
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if (b) {
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/* limit the amount of elements that we accept */
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if (!Ringbuf_Full(b)) {
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ring_data = b->buffer;
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ring_data += ((b->head % b->element_count) * b->element_size);
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}
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}
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return ring_data;
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}
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/****************************************************************************
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* DESCRIPTION: Adds the previously peeked element of data to the end of the
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* ring buffer
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* RETURN: true if the buffer has space and the data element points to the
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* same memory previously peeked.
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* ALGORITHM: none
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* NOTES: Use Ringbuf_Data_Peek with Ringbuf_Data_Put
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*****************************************************************************/
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bool Ringbuf_Data_Put(RING_BUFFER * b, volatile uint8_t *data_element)
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{
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bool status = false;
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volatile uint8_t *ring_data = NULL; /* used to help point ring data */
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if (b) {
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/* limit the amount of elements that we accept */
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if (!Ringbuf_Full(b)) {
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ring_data = b->buffer;
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ring_data += ((b->head % b->element_count) * b->element_size);
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if (ring_data == data_element) {
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/* same chunk of memory - okay to signal the head */
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b->head++;
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status = true;
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}
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}
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}
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return status;
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}
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/****************************************************************************
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* DESCRIPTION: Configures the ring buffer
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* RETURN: none
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* ALGORITHM: none
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* NOTES:
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* element_count must be a power of two
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*****************************************************************************/
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void Ringbuf_Init(
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RING_BUFFER * b, /* ring buffer structure */
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volatile uint8_t * buffer, /* data block or array of data */
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unsigned element_size, /* size of one element in the data block */
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unsigned element_count)
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{ /* number of elements in the data block */
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if (b) {
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b->head = 0;
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b->tail = 0;
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b->buffer = buffer;
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b->element_size = element_size;
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b->element_count = element_count;
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}
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return;
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}
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#ifdef TEST
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#include <assert.h>
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#include <string.h>
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#include <limits.h>
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#include "ctest.h"
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/* test the ring buffer */
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static void testRingAroundBuffer(
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Test * pTest,
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RING_BUFFER * test_buffer,
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uint8_t * data_element,
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unsigned element_size,
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unsigned element_count)
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{
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volatile uint8_t *test_data;
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unsigned index;
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unsigned data_index;
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unsigned count;
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unsigned dummy;
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bool status;
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ct_test(pTest, Ringbuf_Empty(test_buffer));
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/* test the ring around the buffer */
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for (index = 0; index < element_count; index++) {
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for (count = 1; count < 4; count++) {
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dummy = index * count;
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for (data_index = 0; data_index < element_size; data_index++) {
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data_element[data_index] = dummy;
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}
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status = Ringbuf_Put(test_buffer, data_element);
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ct_test(pTest, status == true);
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}
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for (count = 1; count < 4; count++) {
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dummy = index * count;
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test_data = Ringbuf_Peek(test_buffer);
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ct_test(pTest, test_data);
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if (test_data) {
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for (data_index = 0; data_index < element_size; data_index++) {
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ct_test(pTest, test_data[data_index] == dummy);
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}
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}
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(void) Ringbuf_Pop(test_buffer, NULL);
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}
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}
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ct_test(pTest, Ringbuf_Empty(test_buffer));
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}
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/* test the ring buffer */
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static void testRingBuf(
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Test * pTest,
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uint8_t * data_store,
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uint8_t * data_element,
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unsigned element_size,
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unsigned element_count)
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{
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RING_BUFFER test_buffer;
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volatile uint8_t *test_data;
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unsigned index;
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unsigned data_index;
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bool status;
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Ringbuf_Init(&test_buffer, data_store, element_size, element_count);
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ct_test(pTest, Ringbuf_Empty(&test_buffer));
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for (data_index = 0; data_index < element_size; data_index++) {
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data_element[data_index] = data_index;
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}
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status = Ringbuf_Put(&test_buffer, data_element);
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ct_test(pTest, status == true);
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ct_test(pTest, !Ringbuf_Empty(&test_buffer));
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test_data = Ringbuf_Peek(&test_buffer);
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for (data_index = 0; data_index < element_size; data_index++) {
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ct_test(pTest, test_data[data_index] == data_element[data_index]);
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}
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ct_test(pTest, !Ringbuf_Empty(&test_buffer));
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(void) Ringbuf_Pop(&test_buffer, NULL);
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ct_test(pTest, Ringbuf_Empty(&test_buffer));
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/* fill to max */
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for (index = 0; index < element_count; index++) {
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for (data_index = 0; data_index < element_size; data_index++) {
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data_element[data_index] = index;
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}
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status = Ringbuf_Put(&test_buffer, data_element);
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ct_test(pTest, status == true);
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ct_test(pTest, !Ringbuf_Empty(&test_buffer));
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}
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/* verify actions on full buffer */
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for (index = 0; index < element_count; index++) {
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for (data_index = 0; data_index < element_size; data_index++) {
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data_element[data_index] = index;
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}
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status = Ringbuf_Put(&test_buffer, data_element);
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ct_test(pTest, status == false);
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ct_test(pTest, !Ringbuf_Empty(&test_buffer));
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}
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/* check buffer full */
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for (index = 0; index < element_count; index++) {
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test_data = Ringbuf_Peek(&test_buffer);
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ct_test(pTest, test_data);
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if (test_data) {
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for (data_index = 0; data_index < element_size; data_index++) {
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ct_test(pTest, test_data[data_index] == index);
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}
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}
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(void) Ringbuf_Pop(&test_buffer, NULL);
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}
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ct_test(pTest, Ringbuf_Empty(&test_buffer));
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testRingAroundBuffer(pTest, &test_buffer, data_element, element_size,
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element_count);
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/* adjust the internal index of Ringbuf to test unsigned wrapping */
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test_buffer.head = UINT_MAX - 1;
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test_buffer.tail = UINT_MAX - 1;
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testRingAroundBuffer(pTest, &test_buffer, data_element, element_size,
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element_count);
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return;
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}
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void testRingBufSize16(
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Test * pTest)
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{
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uint8_t data_element[5];
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uint8_t data_store[sizeof(data_element) * 16];
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testRingBuf(pTest, data_store, data_element, sizeof(data_element),
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sizeof(data_store) / sizeof(data_element));
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}
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void testRingBufSize32(
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Test * pTest)
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{
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uint8_t data_element[16];
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uint8_t data_store[sizeof(data_element) * 32];
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testRingBuf(pTest, data_store, data_element, sizeof(data_element),
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sizeof(data_store) / sizeof(data_element));
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}
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#ifdef TEST_RING_BUFFER
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int main(
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void)
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{
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Test *pTest;
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bool rc;
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pTest = ct_create("Ring Buffer", NULL);
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/* individual tests */
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rc = ct_addTestFunction(pTest, testRingBufSize16);
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assert(rc);
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rc = ct_addTestFunction(pTest, testRingBufSize32);
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assert(rc);
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ct_setStream(pTest, stdout);
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ct_run(pTest);
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(void) ct_report(pTest);
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ct_destroy(pTest);
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return 0;
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}
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#endif
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#endif
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