MMDVMHost-Private/DStarSlowData.cpp
2016-02-03 07:20:48 +00:00

165 lines
4 KiB
C++

/*
* 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 "DStarSlowData.h"
#include "DStarDefines.h"
#include "CRC.h"
#include "Log.h"
#include <cstdio>
#include <cassert>
#include <cstring>
CDStarSlowData::CDStarSlowData() :
m_header(NULL),
m_ptr(0U),
m_buffer(NULL),
m_text(NULL),
m_textPtr(0U),
m_state(SDD_FIRST)
{
m_header = new unsigned char[50U]; // DSTAR_HEADER_LENGTH_BYTES
m_buffer = new unsigned char[DSTAR_DATA_FRAME_LENGTH_BYTES * 2U];
m_text = new unsigned char[24U];
}
CDStarSlowData::~CDStarSlowData()
{
delete[] m_header;
delete[] m_buffer;
delete[] m_text;
}
CDStarHeader* CDStarSlowData::add(const unsigned char* data)
{
assert(data != NULL);
switch (m_state) {
case SDD_FIRST:
m_buffer[0U] = data[9U] ^ DSTAR_SCRAMBLER_BYTES[0U];
m_buffer[1U] = data[10U] ^ DSTAR_SCRAMBLER_BYTES[1U];
m_buffer[2U] = data[11U] ^ DSTAR_SCRAMBLER_BYTES[2U];
m_state = SDD_SECOND;
return NULL;
case SDD_SECOND:
m_buffer[3U] = data[9U] ^ DSTAR_SCRAMBLER_BYTES[0U];
m_buffer[4U] = data[10U] ^ DSTAR_SCRAMBLER_BYTES[1U];
m_buffer[5U] = data[11U] ^ DSTAR_SCRAMBLER_BYTES[2U];
m_state = SDD_FIRST;
break;
}
if ((m_buffer[0U] & DSTAR_SLOW_DATA_TYPE_MASK) != DSTAR_SLOW_DATA_TYPE_HEADER)
return NULL;
if (m_ptr >= 45U)
return NULL;
::memcpy(m_header + m_ptr, m_buffer + 1U, 5U);
m_ptr += 5U;
// Clean up the data
m_header[0U] &= (DSTAR_INTERRUPTED_MASK | DSTAR_URGENT_MASK | DSTAR_REPEATER_MASK);
m_header[1U] = 0x00U;
m_header[2U] = 0x00U;
for (unsigned int i = 3U; i < 39U; i++)
m_header[i] &= 0x7FU;
// Save the CRC for later comparison
unsigned char crc[2U];
::memcpy(crc, m_header + 39U, 2U);
// Add the new CRC
CCRC::addCCITT16(m_header, DSTAR_HEADER_LENGTH_BYTES);
// Compare them
if (::memcmp(crc, m_header + 39U, 2U) != 0) {
if (m_ptr == 45U)
LogMessage("D-Star, invalid slow data header");
::memcpy(m_header + 39U, crc, 2U);
return NULL;
}
return new CDStarHeader(m_header);
}
void CDStarSlowData::start()
{
::memset(m_header, 0x00U, DSTAR_HEADER_LENGTH_BYTES);
m_ptr = 0U;
m_state = SDD_FIRST;
}
void CDStarSlowData::reset()
{
m_ptr = 0U;
m_state = SDD_FIRST;
}
void CDStarSlowData::setText(const char* text)
{
assert(text != NULL);
m_text[0U] = DSTAR_SLOW_DATA_TYPE_TEXT | 0U;
m_text[1U] = text[0U];
m_text[2U] = text[1U];
m_text[3U] = text[2U];
m_text[4U] = text[3U];
m_text[5U] = text[4U];
m_text[6U] = DSTAR_SLOW_DATA_TYPE_TEXT | 1U;
m_text[7U] = text[5U];
m_text[8U] = text[6U];
m_text[9U] = text[7U];
m_text[10U] = text[8U];
m_text[11U] = text[9U];
m_text[12U] = DSTAR_SLOW_DATA_TYPE_TEXT | 2U;
m_text[13U] = text[10U];
m_text[14U] = text[11U];
m_text[15U] = text[12U];
m_text[16U] = text[13U];
m_text[17U] = text[14U];
m_text[18U] = DSTAR_SLOW_DATA_TYPE_TEXT | 3U;
m_text[19U] = text[15U];
m_text[20U] = text[16U];
m_text[21U] = text[17U];
m_text[22U] = text[18U];
m_text[23U] = text[19U];
m_textPtr = 0U;
}
void CDStarSlowData::get(unsigned char* data)
{
assert(data != NULL);
if (m_textPtr < 24U) {
data[0U] = m_text[m_textPtr++] ^ DSTAR_SCRAMBLER_BYTES[0U];
data[1U] = m_text[m_textPtr++] ^ DSTAR_SCRAMBLER_BYTES[1U];
data[2U] = m_text[m_textPtr++] ^ DSTAR_SCRAMBLER_BYTES[2U];
} else {
data[0U] = 'f' ^ DSTAR_SCRAMBLER_BYTES[0U];
data[1U] = 'f' ^ DSTAR_SCRAMBLER_BYTES[1U];
data[2U] = 'f' ^ DSTAR_SCRAMBLER_BYTES[2U];
}
}