/*
* Copyright (C) 2014 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
*
*/
#define __BTSTACK_FILE__ "btstack_slip.c"
/*
* btstack_slip.c
* SLIP encoder/decoder
*/
#include "btstack_slip.h"
#include "btstack_debug.h"
typedef enum {
SLIP_ENCODER_DEFAULT,
SLIP_ENCODER_SEND_DC,
SLIP_ENCODER_SEND_DD
} btstack_slip_encoder_state_t;
// h5 slip state machine
typedef enum {
SLIP_DECODER_UNKNOWN = 1,
SLIP_DECODER_ACTIVE,
SLIP_DECODER_X_C0,
SLIP_DECODER_X_DB,
SLIP_DECODER_COMPLETE
} btstack_slip_decoder_state_t;
// encoder
static btstack_slip_encoder_state_t encoder_state;
static const uint8_t * encoder_data;
static uint16_t encoder_len;
// decoder
static btstack_slip_decoder_state_t decoder_state;
static uint8_t * decoder_buffer;
static uint16_t decoder_max_size;
static uint16_t decoder_pos;
// ENCODER
/**
* @brief Initialise SLIP encoder with data
* @param data
* @param len
*/
void btstack_slip_encoder_start(const uint8_t * data, uint16_t len){
encoder_state = SLIP_ENCODER_DEFAULT;
encoder_data = data;
encoder_len = len;
}
/**
* @brief Check if encoder has data ready
* @return True if data ready
*/
int btstack_slip_encoder_has_data(void){
if (encoder_state != SLIP_ENCODER_DEFAULT) return 1;
return encoder_len > 0;
}
/**
* @brief Get next byte from encoder
* @return Next bytes from encoder
*/
uint8_t btstack_slip_encoder_get_byte(void){
uint8_t next_byte;
switch (encoder_state){
case SLIP_ENCODER_DEFAULT:
next_byte = *encoder_data++;
encoder_len--;
switch (next_byte){
case BTSTACK_SLIP_SOF:
encoder_state = SLIP_ENCODER_SEND_DC;
return 0xdb;
case 0xdb:
encoder_state = SLIP_ENCODER_SEND_DD;
return 0xdb;
default:
return next_byte;
}
break;
case SLIP_ENCODER_SEND_DC:
encoder_state = SLIP_ENCODER_DEFAULT;
return 0x0dc;
case SLIP_ENCODER_SEND_DD:
encoder_state = SLIP_ENCODER_DEFAULT;
return 0x0dd;
default:
log_error("btstack_slip_encoder_get_byte invalid state %x", encoder_state);
return 0x00;
}
}
// Decoder
static void btstack_slip_decoder_reset(void){
decoder_state = SLIP_DECODER_UNKNOWN;
decoder_pos = 0;
}
static void btstack_slip_decoder_store_byte(uint8_t input){
if (decoder_pos >= decoder_max_size){
log_error("btstack_slip_decoder_store_byte: packet to long");
btstack_slip_decoder_reset();
}
decoder_buffer[decoder_pos++] = input;
}
/**
* @brief Initialise SLIP decoder with buffer
* @param buffer to store received data
* @param max_size of buffer
*/
void btstack_slip_decoder_init(uint8_t * buffer, uint16_t max_size){
decoder_buffer = buffer;
decoder_max_size = max_size;
btstack_slip_decoder_reset();
}
/**
* @brief Process received byte
* @param data
*/
void btstack_slip_decoder_process(uint8_t input){
switch(decoder_state){
case SLIP_DECODER_UNKNOWN:
if (input != BTSTACK_SLIP_SOF) break;
btstack_slip_decoder_reset();
decoder_state = SLIP_DECODER_X_C0;
break;
case SLIP_DECODER_COMPLETE:
log_error("btstack_slip_decoder_process called in state COMPLETE");
btstack_slip_decoder_reset();
break;
case SLIP_DECODER_X_C0:
switch(input){
case BTSTACK_SLIP_SOF:
break;
case 0xdb:
decoder_state = SLIP_DECODER_X_DB;
break;
default:
btstack_slip_decoder_store_byte(input);
decoder_state = SLIP_DECODER_ACTIVE;
break;
}
break;
case SLIP_DECODER_X_DB:
switch(input){
case 0xdc:
btstack_slip_decoder_store_byte(BTSTACK_SLIP_SOF);
decoder_state = SLIP_DECODER_ACTIVE;
break;
case 0xdd:
btstack_slip_decoder_store_byte(0xdb);
decoder_state = SLIP_DECODER_ACTIVE;
break;
default:
btstack_slip_decoder_reset();
break;
}
break;
case SLIP_DECODER_ACTIVE:
switch(input){
case BTSTACK_SLIP_SOF:
if (decoder_pos){
decoder_state = SLIP_DECODER_COMPLETE;
} else {
btstack_slip_decoder_reset();
}
break;
case 0xdb:
decoder_state = SLIP_DECODER_X_DB;
break;
default:
btstack_slip_decoder_store_byte(input);
break;
}
break;
}
}
/**
* @brief Get size of decoded frame
* @return size of frame. Size = 0 => frame not complete
*/
uint16_t btstack_slip_decoder_frame_size(void){
switch (decoder_state){
case SLIP_DECODER_COMPLETE:
return decoder_pos;
default:
return 0;
}
}