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/*
* Slamtec LIDAR SDK
*
* Copyright (c) 2014 - 2023 Shanghai Slamtec Co., Ltd.
* http://www.slamtec.com
*
*/
/*
* 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.
*
* 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 THE COPYRIGHT HOLDER 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.
*
*/
#include "sdkcommon.h"
#include "hal/byteorder.h"
#include "hal/abs_rxtx.h"
#include "hal/thread.h"
#include "hal/types.h"
#include "hal/assert.h"
#include "hal/locker.h"
#include "hal/socket.h"
#include "hal/event.h"
#include "sl_lidar_driver.h"
#include "sl_crc.h"
#include <algorithm>
#include "sl_async_transceiver.h"
#include "sl_lidarprotocol_codec.h"
namespace sl { namespace internal {
RPLidarProtocolCodec::RPLidarProtocolCodec()
: IAsyncProtocolCodec()
, _listener(NULL)
, _op_locker(true)
{
onDecodeReset();
}
void RPLidarProtocolCodec::exitLoopMode() {
onDecodeReset();
}
void RPLidarProtocolCodec::setMessageListener(IProtocolMessageListener* listener)
{
rp::hal::AutoLocker l(_op_locker);
_listener = listener;
}
size_t RPLidarProtocolCodec::estimateLength(message_autoptr_t& message)
{
size_t actualSize = 2; //1-byte's sync byte, 1-byte's cmd byte
if (message->cmd & RPLIDAR_CMDFLAG_HAS_PAYLOAD) {
actualSize += (message->getPayloadSize() & 0xFF);
actualSize += 2; //1-byte for size field, 1-byte for checksum
}
return actualSize;
}
void RPLidarProtocolCodec::onEncodeData(message_autoptr_t& message, _u8* buffer, size_t* size)
{
_u8 checksum = 0;
size_t writeSize = std::min<size_t>(*size, estimateLength(message));
size_t currentPos = 0;
while (currentPos < writeSize) {
_u8 currentTxByte;
switch (currentPos) {
case 0: // sync byte
currentTxByte = RPLIDAR_CMD_SYNC_BYTE;
break;
case 1: // cmd byte
currentTxByte = message->cmd;
break;
case 2: // size byte
currentTxByte = (_u8)message->getPayloadSize();
break;
default:
{
size_t payloadPos = currentPos - 3;
if (payloadPos == message->getPayloadSize()) {
// checksum byte
currentTxByte = checksum;
assert(currentPos + 1 == writeSize);
}
else {
// payload
currentTxByte = message->getDataBuf()[payloadPos];
}
}
}
checksum ^= currentTxByte;
buffer[currentPos++] = currentTxByte;
} while (0);
*size = currentPos;
}
void RPLidarProtocolCodec::onDecodeReset() {
rp::hal::AutoLocker autolock(_op_locker);
// flush the pending data
_decodingMessage.cleanData();
// reset to initial state
_rx_pos = 0;
_working_states = STATUS_WAIT_SYNC1;
}
void RPLidarProtocolCodec::onDecodeData(const void* buffer, size_t size)
{
rp::hal::AutoLocker autolock(_op_locker);
const _u8* data = reinterpret_cast<const _u8*>(buffer);
const _u8* dataEnd = data + size;
while (data != dataEnd) {
_u8 currentByte = *data;
++data;
switch (_working_states & ((_u32)STATUS_LOOP_MODE_FLAG - 1)) {
case STATUS_WAIT_SYNC1:
if (currentByte == RPLIDAR_ANS_SYNC_BYTE1) {
_working_states = STATUS_WAIT_SYNC2;
}
break;
case STATUS_WAIT_SYNC2:
if (currentByte == RPLIDAR_ANS_SYNC_BYTE2) {
_working_states = STATUS_WAIT_SIZE_FLAG;
_rx_pos = 0; // init rx pos for recv size and flag
}
else {
// reset to the initial state
_working_states = STATUS_WAIT_SYNC1;
}
break;
case STATUS_WAIT_SIZE_FLAG:
{
assert(sizeof(_decodingMessage.len) >= 4);
_u8* byteArr = reinterpret_cast<_u8*>(&_decodingMessage.len);
byteArr[_rx_pos++] = currentByte;
if (_rx_pos == 4) {
_working_states = STATUS_WAIT_TYPE;
_decodingMessage.len = le32_to_cpu(_decodingMessage.len);
// 30bit size + 2bit flag has been received
_u32 flagbits = (_u32)(_decodingMessage.len >> RPLIDAR_ANS_HEADER_SUBTYPE_SHIFT);
if (flagbits & RPLIDAR_ANS_PKTFLAG_LOOP) {
_working_states |= STATUS_LOOP_MODE_FLAG;
}
_decodingMessage.len = (_decodingMessage.len & RPLIDAR_ANS_HEADER_SIZE_MASK);
// alloc buffer
_decodingMessage.fillData(NULL, _decodingMessage.getPayloadSize());
_rx_pos = 0;
}
}
break;
case STATUS_WAIT_TYPE:
// save the type field as a cmd
_decodingMessage.cmd = currentByte;
// recv payload...
_working_states = (_working_states & STATUS_LOOP_MODE_FLAG)
| STATUS_RECV_PAYLOAD;
if (!_decodingMessage.getPayloadSize()) {
// zero payload packet?
_working_states = STATUS_WAIT_SYNC1;
}
break;
case STATUS_RECV_PAYLOAD:
_decodingMessage.getDataBuf()[_rx_pos++] = currentByte;
if ((size_t)_rx_pos == _decodingMessage.getPayloadSize()) {
if (_working_states & STATUS_LOOP_MODE_FLAG) {
// rewind to the payload recv status in loop mode
_rx_pos = 0;
}
else {
// reset the decoder
_working_states = STATUS_WAIT_SYNC1;
}
IProtocolMessageListener* cachedLister = _listener;
autolock.forceUnlock(); //unlock the oplock to prevent deadlock
if (cachedLister) {
cachedLister->onProtocolMessageDecoded(_decodingMessage);
}
_op_locker.lock(); // relock it
}
break;
}
}
}
}}
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