MMDVMHost-Private/YSFFICH.cpp
2016-07-05 17:51:16 +01:00

209 lines
5.2 KiB
C++

/*
* Copyright (C) 2009-2016 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 "YSFConvolution.h"
#include "YSFDefines.h"
#include "Golay24128.h"
#include "YSFFICH.h"
#include "CRC.h"
#include "Log.h"
#include <cstdio>
#include <cassert>
#include <cstring>
const unsigned char BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
#define READ_BIT1(p,i) (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
const unsigned int INTERLEAVE_TABLE[] = {
0U, 40U, 80U, 120U, 160U,
2U, 42U, 82U, 122U, 162U,
4U, 44U, 84U, 124U, 164U,
6U, 46U, 86U, 126U, 166U,
8U, 48U, 88U, 128U, 168U,
10U, 50U, 90U, 130U, 170U,
12U, 52U, 92U, 132U, 172U,
14U, 54U, 94U, 134U, 174U,
16U, 56U, 96U, 136U, 176U,
18U, 58U, 98U, 138U, 178U,
20U, 60U, 100U, 140U, 180U,
22U, 62U, 102U, 142U, 182U,
24U, 64U, 104U, 144U, 184U,
26U, 66U, 106U, 146U, 186U,
28U, 68U, 108U, 148U, 188U,
30U, 70U, 110U, 150U, 190U,
32U, 72U, 112U, 152U, 192U,
34U, 74U, 114U, 154U, 194U,
36U, 76U, 116U, 156U, 196U,
38U, 78U, 118U, 158U, 198U};
CYSFFICH::CYSFFICH() :
m_fich(NULL)
{
m_fich = new unsigned char[6U];
}
CYSFFICH::~CYSFFICH()
{
delete[] m_fich;
}
bool CYSFFICH::decode(const unsigned char* bytes)
{
assert(bytes != NULL);
// Skip the sync bytes
bytes += YSF_SYNC_LENGTH_BYTES;
CYSFConvolution viterbi;
viterbi.start();
// Deinterleave the FICH and send bits to the Viterbi decoder
for (unsigned int i = 0U; i < 100U; i++) {
unsigned int n = INTERLEAVE_TABLE[i];
uint8_t s0 = READ_BIT1(bytes, n) ? 1U : 0U;
n++;
uint8_t s1 = READ_BIT1(bytes, n) ? 1U : 0U;
viterbi.decode(s0, s1);
}
unsigned char output[13U];
viterbi.chainback(output, 96U);
unsigned int b0 = CGolay24128::decode24128(output + 0U);
unsigned int b1 = CGolay24128::decode24128(output + 3U);
unsigned int b2 = CGolay24128::decode24128(output + 6U);
unsigned int b3 = CGolay24128::decode24128(output + 9U);
m_fich[0U] = (b0 >> 4) & 0xFFU;
m_fich[1U] = ((b0 << 4) & 0xF0U) | ((b1 >> 8) & 0x0FU);
m_fich[2U] = (b1 >> 0) & 0xFFU;
m_fich[3U] = (b2 >> 4) & 0xFFU;
m_fich[4U] = ((b2 << 4) & 0xF0U) | ((b3 >> 8) & 0x0FU);
m_fich[5U] = (b3 >> 0) & 0xFFU;
return CCRC::checkCCITT162(m_fich, 6U);
}
void CYSFFICH::encode(unsigned char* bytes)
{
assert(bytes != NULL);
// Skip the sync bytes
bytes += YSF_SYNC_LENGTH_BYTES;
CCRC::addCCITT162(m_fich, 6U);
unsigned int b0 = ((m_fich[0U] << 4) & 0xFF0U) | ((m_fich[1U] >> 4) & 0x00FU);
unsigned int b1 = ((m_fich[1U] << 8) & 0xF00U) | ((m_fich[2U] >> 0) & 0x0FFU);
unsigned int b2 = ((m_fich[3U] << 4) & 0xFF0U) | ((m_fich[4U] >> 4) & 0x00FU);
unsigned int b3 = ((m_fich[4U] << 8) & 0xF00U) | ((m_fich[5U] >> 0) & 0x0FFU);
unsigned int c0 = CGolay24128::encode24128(b0);
unsigned int c1 = CGolay24128::encode24128(b1);
unsigned int c2 = CGolay24128::encode24128(b2);
unsigned int c3 = CGolay24128::encode24128(b3);
unsigned char conv[13U];
conv[0U] = (c0 >> 16) & 0xFFU;
conv[1U] = (c0 >> 8) & 0xFFU;
conv[2U] = (c0 >> 0) & 0xFFU;
conv[3U] = (c1 >> 16) & 0xFFU;
conv[4U] = (c1 >> 8) & 0xFFU;
conv[5U] = (c1 >> 0) & 0xFFU;
conv[6U] = (c2 >> 16) & 0xFFU;
conv[7U] = (c2 >> 8) & 0xFFU;
conv[8U] = (c2 >> 0) & 0xFFU;
conv[9U] = (c3 >> 16) & 0xFFU;
conv[10U] = (c3 >> 8) & 0xFFU;
conv[11U] = (c3 >> 0) & 0xFFU;
conv[12U] = 0x00U;
CYSFConvolution convolution;
unsigned char convolved[25U];
convolution.encode(conv, convolved, 100U);
unsigned int j = 0U;
for (unsigned int i = 0U; i < 100U; i++) {
unsigned int n = INTERLEAVE_TABLE[i];
bool s0 = READ_BIT1(convolved, j) != 0U;
j++;
bool s1 = READ_BIT1(convolved, j) != 0U;
j++;
WRITE_BIT1(bytes, n, s0);
n++;
WRITE_BIT1(bytes, n, s1);
}
}
unsigned char CYSFFICH::getFI() const
{
return (m_fich[0U] >> 6) & 0x03U;
}
unsigned char CYSFFICH::getCM() const
{
return (m_fich[0U] >> 2) & 0x03U;
}
unsigned char CYSFFICH::getBN() const
{
return m_fich[0U] & 0x03U;
}
unsigned char CYSFFICH::getBT() const
{
return (m_fich[1U] >> 6) & 0x03U;
}
unsigned char CYSFFICH::getFN() const
{
return (m_fich[1U] >> 3) & 0x07U;
}
unsigned char CYSFFICH::getFT() const
{
return m_fich[1U] & 0x07U;
}
unsigned char CYSFFICH::getDT() const
{
return m_fich[2U] & 0x03U;
}
void CYSFFICH::setMR(unsigned char mr)
{
m_fich[2U] &= 0xC7U;
m_fich[2U] |= (mr << 3) & 0x38U;
}
void CYSFFICH::setVoIP(bool on)
{
if (on)
m_fich[2U] |= 0x04U;
else
m_fich[2U] &= 0xFBU;
}