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ringbuffer.c
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ringbuffer.c
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/* Copyright (c) 2013, Regents of the University of California
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the <organization> nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "common.h"
#include <stdlib.h>
#include <stdio.h>
#include "ringbuffer.h"
void rb_clear(rb *x) {
x->head = 0;
x->next = 0;
x->free = x->size;
}
//will use preallocated memory if supplied
uint8_t rb_init(rb *x, uint16_t size, uint8_t *ptr) {
x->ptr = (ptr) ? ptr : (uint8_t*) malloc(size);
if (!x->ptr) {
#ifdef DEBUG
printf("Unable to malloc(%d)\r\n", size);
#endif
return 0;
}
x->head = 0;
x->next = 0;
x->overflow = 0;
x->size = size;
x->free = size;
return 1;
}
void rb_pushStr(rb *x, uint8_t *str) {
while (*str) {
rb_push(x, *str);
str++;
}
}
__monitor void rb_push(rb *x, uint8_t byte) {
if (x->free) {
x->free--;
// add byte
x->ptr[x->next] = byte;
// increment next ptr
if (++x->next == x->size)
x->next = 0;
} else {
x->overflow++;
}
}
__monitor uint16_t rb_pop(rb *x) {
uint8_t ret;
if (rb_len(x) == 0) return NO_DATA;
ret = x->ptr[x->head++];
// increment head
if (x->head == x->size) x->head = 0;
x->free++;
return ret;
}
/* This function will mark a section of the ringbuffer as 'read'
** this function is optimized such that you should /NEVER/ mark
** it as being read beyond the buffer size.
*/
__monitor void rb_markRead(rb *x, uint16_t len) {
if ((x->size - x->free) < len) {
return;
}
x->head += len;
if (x->head == x->size) x->head = 0;
x->free += len;
return;
}