113 lines
3.6 KiB
C
113 lines
3.6 KiB
C
|
/* Copyright (c) 2015 Nordic Semiconductor. All Rights Reserved.
|
||
|
|
*
|
||
|
|
* The information contained herein is property of Nordic Semiconductor ASA.
|
||
|
|
* Terms and conditions of usage are described in detail in NORDIC
|
||
|
|
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
|
||
|
|
*
|
||
|
|
* Licensees are granted free, non-transferable use of the information. NO
|
||
|
|
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
|
||
|
|
* the file.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "slip.h"
|
||
|
|
#include "nrf_error.h"
|
||
|
|
|
||
|
|
#define SLIP_END 0300 /* indicates end of packet */
|
||
|
|
#define SLIP_ESC 0333 /* indicates byte stuffing */
|
||
|
|
#define SLIP_ESC_END 0334 /* ESC ESC_END means END data byte */
|
||
|
|
#define SLIP_ESC_ESC 0335 /* ESC ESC_ESC means ESC data byte */
|
||
|
|
|
||
|
|
|
||
|
|
uint32_t slip_encode(uint8_t * p_output, uint8_t * p_input, uint32_t input_length, uint32_t output_buffer_length)
|
||
|
|
{
|
||
|
|
uint32_t input_index;
|
||
|
|
uint32_t output_index;
|
||
|
|
|
||
|
|
for (input_index = 0, output_index = 0; input_index < input_length && output_index < output_buffer_length; input_index++)
|
||
|
|
{
|
||
|
|
switch (p_input[input_index])
|
||
|
|
{
|
||
|
|
case SLIP_END:
|
||
|
|
p_output[output_index++] = SLIP_END;
|
||
|
|
p_output[output_index++] = SLIP_ESC_END;
|
||
|
|
break;
|
||
|
|
|
||
|
|
case SLIP_ESC:
|
||
|
|
p_output[output_index++] = SLIP_ESC;
|
||
|
|
p_output[output_index++] = SLIP_ESC_ESC;
|
||
|
|
break;
|
||
|
|
|
||
|
|
default:
|
||
|
|
p_output[output_index++] = p_input[input_index];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
p_output[output_index++] = (uint8_t)SLIP_END;
|
||
|
|
p_output[output_index++] = (uint8_t)SLIP_END; // clarify that the packet has ended.
|
||
|
|
|
||
|
|
return output_index;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
uint32_t slip_decoding_add_char(uint8_t c, buffer_t * p_buf, slip_state_t * current_state)
|
||
|
|
{
|
||
|
|
switch (*current_state)
|
||
|
|
{
|
||
|
|
case SLIP_DECODING:
|
||
|
|
if (c == SLIP_END)
|
||
|
|
{
|
||
|
|
*current_state = SLIP_END_RECEIVED;
|
||
|
|
}
|
||
|
|
else if (c == SLIP_ESC)
|
||
|
|
{
|
||
|
|
*current_state = SLIP_END_RECEIVED;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
p_buf->p_buffer[p_buf->current_index++] = c;
|
||
|
|
p_buf->current_length++;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case SLIP_ESC_RECEIVED:
|
||
|
|
if (c == SLIP_ESC_ESC)
|
||
|
|
{
|
||
|
|
p_buf->p_buffer[p_buf->current_index++] = SLIP_ESC;
|
||
|
|
p_buf->current_length++;
|
||
|
|
*current_state = SLIP_DECODING;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
// violation of protocol
|
||
|
|
*current_state = SLIP_CLEARING_INVALID_PACKET;
|
||
|
|
return NRF_ERROR_INVALID_DATA;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case SLIP_END_RECEIVED:
|
||
|
|
if (c == SLIP_ESC_END)
|
||
|
|
{
|
||
|
|
p_buf->p_buffer[p_buf->current_index++] = SLIP_END;
|
||
|
|
p_buf->current_length++;
|
||
|
|
*current_state = SLIP_DECODING;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
// packet is finished
|
||
|
|
*current_state = SLIP_DECODING;
|
||
|
|
return NRF_SUCCESS;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case SLIP_CLEARING_INVALID_PACKET:
|
||
|
|
if (c == SLIP_END)
|
||
|
|
{
|
||
|
|
*current_state = SLIP_DECODING;
|
||
|
|
p_buf->current_index = 0;
|
||
|
|
p_buf->current_length = 0;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
return NRF_ERROR_BUSY;
|
||
|
|
}
|