YSFClients/YSFGateway/GPS.cpp

/*
*   Copyright (C) 2016 by Jonathan Naylor G4KLX
*
*   This program is free software; you can redistribute it and/or modify
*   it under the terms of the GNU General Public License as published by
*   the Free Software Foundation; either version 2 of the License, or
*   (at your option) any later version.
*
*   This program is distributed in the hope that it will be useful,
*   but WITHOUT ANY WARRANTY; without even the implied warranty of
*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*   GNU General Public License for more details.
*
*   You should have received a copy of the GNU General Public License
*   along with this program; if not, write to the Free Software
*   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "GPS.h"
#include "YSFPayload.h"
#include "YSFDefines.h"
#include "Utils.h"
#include "Log.h"

#include <cstdio>
#include <cassert>
#include <cstring>

const unsigned char NULL_GPS[] = {0x47U, 0x63U};
const unsigned char SHRT_GPS[] = {0x22U, 0x62U};
const unsigned char LONG_GPS[] = {0x47U, 0x64U};

CGPS::CGPS(const std::string& hostname, unsigned int port, const std::string& password) :
m_hostname(hostname),
m_port(port),
m_password(password),
m_buffer(NULL),
m_dt1(false),
m_dt2(false),
m_sent(false)
{
	assert(port > 0U);

	m_buffer = new unsigned char[20U];
}

CGPS::~CGPS()
{
	delete[] m_buffer;
}

void CGPS::data(const unsigned char* source, const unsigned char* data, unsigned char fi, unsigned char dt, unsigned char fn)
{
	if (m_sent)
		return;

	// In case we had the data but not the source callsign
	if (m_dt1 && m_dt2) {
		transmitGPS(source);
		return;
	}

	CYSFPayload payload;

	if (fi == YSF_FI_COMMUNICATIONS && dt == YSF_DT_VD_MODE1) {
		if (fn == 3U && !m_dt1) {
			bool valid = payload.readVDMode1Data(data, m_buffer);
			if (valid) {
				m_dt1 = true;
				m_dt2 = true;

				// If no GPS data then mark it as complete for this transmission
				if (::memcmp(m_buffer + 1U, NULL_GPS, 2U) == 0) {
					CUtils::dump("Null GPS data received", m_buffer, 20U);
					m_sent = true;
				}

				if (::memcmp(m_buffer + 1U, SHRT_GPS, 2U) == 0) {
					CUtils::dump("Short GPS data received", m_buffer, 20U);
					transmitGPS(source);
				}

				if (::memcmp(m_buffer + 1U, LONG_GPS, 2U) == 0) {
					CUtils::dump("Long GPS data received", m_buffer, 20U);
					transmitGPS(source);
				}
			}
		}
	} else if (fi == YSF_FI_COMMUNICATIONS && dt == YSF_DT_VD_MODE2) {
		if (fn == 6U && !m_dt1) {
			bool valid = payload.readVDMode2Data(data, m_buffer + 0U);
			if (valid) {
				m_dt1 = true;

				// If no GPS data then mark it as complete for this transmission
				if (::memcmp(m_buffer + 1U, NULL_GPS, 2U) == 0) {
					CUtils::dump("Null GPS data received", m_buffer, 20U);
					m_sent = true;
					m_dt2  = true;
				}
			}
		}
		
		if (fn == 7U && !m_dt2) {
			bool valid = payload.readVDMode2Data(data, m_buffer + 10U);
			if (valid) {
				m_dt2  = true;

				if (::memcmp(m_buffer + 1U, SHRT_GPS, 2U) == 0) {
					CUtils::dump("Short GPS data received", m_buffer, 20U);
					transmitGPS(source);
				}

				if (::memcmp(m_buffer + 1U, LONG_GPS, 2U) == 0) {
					CUtils::dump("Long GPS data received", m_buffer, 20U);
					transmitGPS(source);
				}
			}
		}
	}
}

void CGPS::reset()
{
	m_dt1  = false;
	m_dt2  = false;
	m_sent = false;
}

void CGPS::transmitGPS(const unsigned char* source)
{
	// We don't know who its from!
	if (::memcmp(source, "          ", YSF_CALLSIGN_LENGTH) == 0)
		return;

	for (unsigned int i = 5U; i < 11U; i++) {
		unsigned char b = m_buffer[i] & 0xF0U;
		if (b != 0x50U && b != 0x30U)
			return;                                // error/unknown
	}

	unsigned int tens = m_buffer[5U] & 0x0FU;
	unsigned int units = m_buffer[6U] & 0x0FU;
	unsigned int lat_deg = (tens * 10U) + units;
	if (tens > 9U || units > 9U || lat_deg > 89U)
		return;                                // error/unknown

	tens = m_buffer[7U] & 0x0FU;
	units = m_buffer[8U] & 0x0FU;
	unsigned int lat_min = (tens * 10U) + units;
	if (tens > 9U || units > 9U || lat_min > 59U)
		return;                                // error/unknown

	tens = m_buffer[9U] & 0x0FU;
	units = m_buffer[10U] & 0x0FU;
	unsigned int lat_min_frac = (tens * 10U) + units;
	if (tens > 9U || units > 10U || lat_min_frac > 99U)    // units > 10 ??? .. more buggy Yaesu firmware ?
		return;                                // error/unknown

	int lat_dir;
	unsigned char b = m_buffer[6U] & 0xF0U;                            // currently a guess
	if (b == 0x30U)
		lat_dir = 1;                           // N
	else if (b == 0x50U)
		lat_dir = -1;                          // S
	else
		return;                                // error/unknown

	unsigned int lon_deg;
	b = m_buffer[9U] & 0xF0U;
	if (b == 0x50U) {
	    // lon deg 0 to 9, and 100 to 179
		b = m_buffer[11U];
		if (b >= 0x76U && b <= 0x7FU)
			lon_deg = b - 0x76U;               // 0 to 9
		else if (b >= 0x6CU && b <= 0x75U)
			lon_deg = 100U + (b - 0x6CU);      // 100 to 109
		else if (b >= 0x16U && b <= 0x6BU)
			lon_deg = 110U + (b - 0x16U);      // 110 to 179
		else
			return;                            // error/unknown
	} else if (b == 0x30U) {
	    // lon deg 10 to 99
		b = m_buffer[11U];
		if (b >= 0x26U && b <= 0x7FU)
			lon_deg = 10U + (b - 0x26U);       // 10 to 99
		else
			return;                            // error/unknown
	} else {
		return;                                // error/unknown
	}

	unsigned int lon_min;
	b = m_buffer[12U];
	if (b >= 0x58U && b <= 0x61U)
		lon_min = b - 0x58U;                   // 0 to 9
	else if (b >= 0x26U && b <= 0x57U)
		lon_min = 10U + (b - 0x26U);            // 10 to 59
	else
		return;                                // error/unknown

	unsigned int lon_min_frac;
	b = m_buffer[13U];
	if (b >= 0x1CU && b <= 0x7FU)
		lon_min_frac = b - 0x1CU;
	else
		return;                                // error/unknown

	int lon_dir;
	b = m_buffer[10U] & 0xF0U;
	if (b == 0x30U)
		lon_dir = 1;                           // E
	else if (b == 0x50U)
		lon_dir = -1;                          // W
	else
		return;                                // error/unknown

	unsigned int lat_sec = lat_min_frac * 60U;
	lat_sec = (lat_sec + (lat_sec % 100U)) / 100U;    // with rounding

	unsigned int lon_sec = lon_min_frac * 60U;
	lon_sec = (lon_sec + (lon_sec % 100U)) / 100U;    // with rounding

	// >= 0 is north, < 0 is south
	float latitude = lat_deg + ((lat_min + ((float)lat_min_frac * 0.01F)) * (1.0F / 60.0F));
	latitude *= lat_dir;

	// >= 0 is east, < 0 is west
	float longitude = lon_deg + ((lon_min + ((float)lon_min_frac * 0.01F)) * (1.0F / 60.0F));
	longitude *= lon_dir;

	m_sent = true;
}