btstack/src/btstack_ring_buffer.c
2016-10-18 14:14:04 +02:00

116 lines
4.3 KiB
C

/*
* Copyright (C) 2016 BlueKitchen GmbH
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* 4. Any redistribution, use, or modification is done solely for
* personal benefit and not for any commercial purpose or for
* monetary gain.
*
* THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH 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 MATTHIAS
* RINGWALD OR CONTRIBUTORS 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.
*
* Please inquire about commercial licensing options at
* contact@bluekitchen-gmbh.com
*
*/
/*
* btstack_ring_buffer.c
*
*/
#include <stdlib.h>
#include <stdio.h>
#include "btstack_ring_buffer.h"
#define ERROR_CODE_MEMORY_CAPACITY_EXCEEDED 0x07
// init ring buffer
void btstack_ring_buffer_init(btstack_ring_buffer_t * ring_buffer, uint8_t * storage, uint16_t storage_size){
ring_buffer->storage = storage;
ring_buffer->size = storage_size;
ring_buffer->last_read_index = 0;
ring_buffer->last_written_index = 0;
ring_buffer->full = 0;
}
int btstack_ring_buffer_bytes_available(btstack_ring_buffer_t * ring_buffer){
if (ring_buffer->full) return ring_buffer->size;
int diff = ring_buffer->last_written_index - ring_buffer->last_read_index;
if (diff >= 0) return diff;
return diff + ring_buffer->size;
}
// test if ring buffer is empty
int btstack_ring_buffer_empty(btstack_ring_buffer_t * ring_buffer){
return btstack_ring_buffer_bytes_available(ring_buffer) == 0;
}
//
int btstack_ring_buffer_bytes_free(btstack_ring_buffer_t * ring_buffer){
return ring_buffer->size - btstack_ring_buffer_bytes_available(ring_buffer);
}
// add byte block to ring buffer,
int btstack_ring_buffer_write(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint16_t data_length){
if (btstack_ring_buffer_bytes_free(ring_buffer) < data_length){
return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
}
int count = 0;
while (count < data_length){
if (ring_buffer->last_written_index < ring_buffer->size - 1){
ring_buffer->last_written_index++;
} else {
ring_buffer->last_written_index = 0;
}
ring_buffer->storage[ring_buffer->last_written_index] = data[count++];
}
if (ring_buffer->last_written_index == ring_buffer->last_read_index){
ring_buffer->full = 1;
}
return 0;
}
// fetch data_length bytes from ring buffer
void btstack_ring_buffer_read(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint16_t data_length, uint16_t * number_of_bytes_read){
uint32_t count = 0;
while (count < data_length && btstack_ring_buffer_bytes_available(ring_buffer)){
if (ring_buffer->last_read_index < ring_buffer->last_written_index ) {
ring_buffer->last_read_index++;
} else {
if (ring_buffer->last_read_index < ring_buffer->size - 1){
ring_buffer->last_read_index++;
} else {
ring_buffer->last_read_index = 0;
}
}
ring_buffer->full = 0;
data[count++] = ring_buffer->storage[ring_buffer->last_read_index];
}
*number_of_bytes_read = count;
}