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#include <QtBluetooth/QBluetoothServiceInfo>
#include "metawatchbttransport.h"
namespace
{
const quint8 bit_rev_table[16] = {
0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15
};
const quint16 crc_table[256] = {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
};
#if 0 /* This snippet was used to build the table seen above. */
quint16 remainder;
int dividend;
quint8 bit;
for (dividend = 0; dividend < 256; dividend++) {
remainder = dividend << 8;
for (bit = 8; bit > 0; bit--) {
if (remainder & 0x8000) {
remainder = (remainder << 1) ^ 0x1021;
} else {
remainder = (remainder << 1);
}
}
if ((dividend % 8) == 0) {
printf(",\n0x%04hx", remainder);
} else {
printf(", 0x%04hx", remainder);
}
}
#endif
quint16 compute_crc(const QByteArray &data)
{
const int size = data.size();
quint16 remainder = 0xFFFF;
for (int i = 0; i < size; i++) {
quint8 byte = data[i];
byte = (bit_rev_table[byte & 0xF] << 4) | bit_rev_table[(byte & 0xF0) >> 4];
remainder = crc_table[byte ^ (remainder >> 8)] ^ (remainder << 8);
}
return remainder;
}
}
MetaWatchBTTransport::MetaWatchBTTransport(const QBluetoothAddress &address, QObject *parent) :
MetaWatchTransport(parent), _addr(address), _socket(0)
{
}
MetaWatchBTTransport::~MetaWatchBTTransport()
{
disconnectDevice();
}
bool MetaWatchBTTransport::isDeviceConnected() const
{
return _socket && _socket->state() == QBluetoothSocket::ConnectedState;
}
void MetaWatchBTTransport::sendMessage(quint8 type, quint8 options, const QByteArray &payload)
{
QByteArray packet = encode(type, options, payload);
qDebug() << "Send:" << packet.toHex();
qint64 written = _socket->write(packet);
if (written < packet.size()) {
qWarning() << "Packet not fully writen";
}
}
void MetaWatchBTTransport::connectDevice()
{
qDebug() << "Trying to connect to" << _addr.toString();
if (_socket) {
disconnectDevice();
}
// Sadly, seems that QBluetoothSocket doesn't really like been closed and reopened,
// so we recreate it every time.
_socket = new QBluetoothSocket(QBluetoothSocket::RfcommSocket, this);
connect(_socket, &QBluetoothSocket::connected, this, &MetaWatchBTTransport::handleSocketConnected);
connect(_socket, &QBluetoothSocket::disconnected, this, &MetaWatchBTTransport::handleSocketDisconnected);
connect(_socket, &QBluetoothSocket::readyRead, this, &MetaWatchBTTransport::handleSocketData);
// Let's hardcode MetaWatch's RFCOMM port (1) in order to avoid having
// to look it up (which would need an SDP query).
_socket->connectToService(_addr, 1);
}
void MetaWatchBTTransport::disconnectDevice()
{
if (_socket) {
_socket->close();
_socket->deleteLater();
disconnect(_socket, 0, this, 0);
_socket = 0;
}
}
QByteArray MetaWatchBTTransport::encode(quint8 type, quint8 options, const QByteArray &payload)
{
QByteArray packet;
quint8 message_size = 6 + payload.size();
packet.reserve(message_size);
packet.append(0x01);
packet.append(message_size);
packet.append(type);
packet.append(options);
packet.append(payload);
packet.append("\0\0", 2);
quint16 crc = compute_crc(packet); // Replace CRC with computed CRC
packet[message_size - 2] = crc & 0xFF;
packet[message_size - 1] = crc >> 8;
return packet;
}
bool MetaWatchBTTransport::decode(const QByteArray &packet, quint8 *type, quint8 *options, QByteArray *payload)
{
if (packet.size() < 6) {
qWarning() << "Message too short";
}
if (packet.at(0) != 0x1) {
qWarning() << "Invalid packet header";
return false;
}
quint8 message_size = packet[1];
if (message_size < 6 || message_size > 32 || message_size != packet.size()) {
qWarning() << "Invalid message size:" << message_size;
}
*type = packet[2];
*options = packet[3];
*payload = packet.mid(4, message_size - 6);
// Don't compare received CRC... what for? RFCOMM already guarantees reliability.
return true;
}
void MetaWatchBTTransport::handleSocketConnected()
{
qDebug() << "MW connected";
emit connected();
}
void MetaWatchBTTransport::handleSocketDisconnected()
{
qDebug() << "MW disconnected";
emit disconnected();
}
void MetaWatchBTTransport::handleSocketData()
{
const int min_message_size = 6;
while (_socket->bytesAvailable() >= min_message_size) {
char header[2];
qint64 bytes_read = _socket->peek(header, sizeof(header));
if (bytes_read < 2) {
qWarning() << "Unable to peek received data";
break;
}
if (header[0] != 0x01 || header[1] > 32) {
qWarning() << "Received garbage data";
_socket->readAll(); // let's discard all pending data.
break;
}
if (_socket->bytesAvailable() < header[1]) {
// Not enough data to complete the entire frame
break;
}
QByteArray data = _socket->read(header[1]);
if (data.size() != header[1]) {
qWarning() << "Received incomplete packet";
_socket->readAll(); // discard all other pending data.
break;
}
qDebug() << "Recv:" << data.toHex();
quint8 type, options;
QByteArray payload;
if (decode(data, &type, &options, &payload)) {
emit messageReceived(type, options, payload);
} else {
qWarning() << "Failed to decode message from metawatch:" << data.toHex();
}
}
}
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