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Copy pathbtstack_ring_buffer.c
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155 lines (129 loc) · 5.77 KB
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/*
* 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 BLUEKITCHEN
* GMBH 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
*
*/
#define BTSTACK_FILE__ "btstack_ring_buffer.c"
/*
* btstack_ring_buffer.c
*
*/
#include <string.h>
#include "btstack_ring_buffer.h"
#include "btstack_util.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, uint32_t storage_size){
ring_buffer->storage = storage;
ring_buffer->size = storage_size;
btstack_ring_buffer_reset(ring_buffer);
}
void btstack_ring_buffer_reset(btstack_ring_buffer_t * ring_buffer){
ring_buffer->last_read_index = 0;
ring_buffer->last_written_index = 0;
ring_buffer->full = 0;
}
uint32_t 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) == 0u;
}
//
uint32_t 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, uint32_t data_length){
if (btstack_ring_buffer_bytes_free(ring_buffer) < data_length){
return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
}
// simplify logic below by asserting data_length > 0
if (data_length == 0u) return 0u;
uint32_t remaining_data_length = data_length;
const uint8_t * remaining_data = data;
// copy first chunk
unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_written_index;
unsigned int bytes_to_copy = btstack_min(bytes_until_end, remaining_data_length);
(void)memcpy(&ring_buffer->storage[ring_buffer->last_written_index], remaining_data, bytes_to_copy);
remaining_data_length -= bytes_to_copy;
remaining_data += bytes_to_copy;
// update last written index
ring_buffer->last_written_index += bytes_to_copy;
if (ring_buffer->last_written_index == ring_buffer->size){
ring_buffer->last_written_index = 0;
}
// copy second chunk
if (remaining_data_length != 0) {
(void)memcpy(&ring_buffer->storage[0], remaining_data, remaining_data_length);
ring_buffer->last_written_index += remaining_data_length;
}
// mark buffer as full
if (ring_buffer->last_written_index == ring_buffer->last_read_index){
ring_buffer->full = 1;
}
return ERROR_CODE_SUCCESS;
}
// fetch data_length bytes from ring buffer
void btstack_ring_buffer_read(btstack_ring_buffer_t * ring_buffer, uint8_t * data, uint32_t data_length, uint32_t * number_of_bytes_read){
// limit data to get and report
uint32_t remaining_data_length = btstack_min(data_length, btstack_ring_buffer_bytes_available(ring_buffer));
*number_of_bytes_read = remaining_data_length;
// simplify logic below by asserting remaining_data_length > 0
if (remaining_data_length == 0u) return;
uint8_t * remaining_data = data;
// copy first chunk
unsigned int bytes_until_end = ring_buffer->size - ring_buffer->last_read_index;
unsigned int bytes_to_copy = btstack_min(bytes_until_end, remaining_data_length);
(void)memcpy(remaining_data, &ring_buffer->storage[ring_buffer->last_read_index],
bytes_to_copy);
remaining_data_length -= bytes_to_copy;
remaining_data += bytes_to_copy;
// update last read index
ring_buffer->last_read_index += bytes_to_copy;
if (ring_buffer->last_read_index == ring_buffer->size){
ring_buffer->last_read_index = 0;
}
// copy second chunk
if (remaining_data_length != 0) {
(void)memcpy(remaining_data, &ring_buffer->storage[0], remaining_data_length);
ring_buffer->last_read_index += remaining_data_length;
}
// clear full flag
ring_buffer->full = 0;
}