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/*
* Copyright (C) 2020,2021 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 "M17Convolution.h"
#include <cstdio>
#include <cassert>
#include <cstring>
#include <cstdlib>
const uint32_t PUNCTURE_LIST_LINK_SETUP_COUNT = 60U;
const uint32_t PUNCTURE_LIST_LINK_SETUP[] = {
2U, 6U, 10U, 14U, 18U, 22U, 26U, 30U, 34U, 38U, 42U, 46U, 50U, 54U, 58U, 63U, 67U, 71U, 75U, 79U, 83U,
87U, 91U, 95U, 99U, 103U, 107U, 111U, 115U, 119U, 124U, 128U, 132U, 136U, 140U, 144U, 148U, 152U, 156U, 160U, 164U, 168U,
172U, 176U, 180U, 185U, 189U, 193U, 197U, 201U, 205U, 209U, 213U, 217U, 221U, 225U, 229U, 233U, 237U, 241U, 246U, 250U, 254U,
258U, 262U, 266U, 270U, 274U, 278U, 282U, 286U, 290U, 294U, 298U, 302U, 307U, 311U, 315U, 319U, 323U, 327U, 331U, 335U, 339U,
343U, 347U, 351U, 355U, 359U, 363U, 368U, 372U, 376U, 380U, 384U, 388U, 392U, 396U, 400U, 404U, 408U, 412U, 416U, 420U, 424U,
429U, 433U, 437U, 441U, 445U, 449U, 453U, 457U, 461U, 465U, 469U, 473U, 477U, 481U, 485U};
const uint32_t PUNCTURE_LIST_DATA_COUNT = 12U;
const uint32_t PUNCTURE_LIST_DATA[] = {
11U, 23U, 35U, 47U, 59U, 71U, 83U, 95U, 107U, 119U, 131U, 143U, 155U, 167U, 179U, 191U, 203U, 215U, 227U, 239U, 251U,
263U, 275U, 287U};
const uint8_t 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 uint8_t BRANCH_TABLE1[] = {0U, 0U, 0U, 0U, 2U, 2U, 2U, 2U};
const uint8_t BRANCH_TABLE2[] = {0U, 2U, 2U, 0U, 0U, 2U, 2U, 0U};
const uint32_t NUM_OF_STATES_D2 = 8U;
const uint32_t NUM_OF_STATES = 16U;
const uint32_t M = 4U;
const uint32_t K = 5U;
CM17Convolution::CM17Convolution() :
m_metrics1(NULL),
m_metrics2(NULL),
m_oldMetrics(NULL),
m_newMetrics(NULL),
m_decisions(NULL),
m_dp(NULL)
{
m_metrics1 = new uint16_t[20U];
m_metrics2 = new uint16_t[20U];
m_decisions = new uint64_t[300U];
}
CM17Convolution::~CM17Convolution()
{
delete[] m_metrics1;
delete[] m_metrics2;
delete[] m_decisions;
}
void CM17Convolution::encodeLinkSetup(const uint8_t* in, uint8_t* out) const
{
assert(in != NULL);
assert(out != NULL);
uint8_t temp1[31U];
::memset(temp1, 0x00U, 31U);
::memcpy(temp1, in, 30U);
uint8_t temp2[61U];
encode(temp1, temp2, 244U);
uint32_t n = 0U;
uint32_t index = 0U;
for (uint32_t i = 0U; i < 488U; i++) {
if (i != PUNCTURE_LIST_LINK_SETUP[index]) {
bool b = READ_BIT1(temp2, i);
WRITE_BIT1(out, n, b);
n++;
} else {
index++;
}
}
}
void CM17Convolution::encodeData(const uint8_t* in, uint8_t* out) const
{
assert(in != NULL);
assert(out != NULL);
uint8_t temp1[19U];
::memset(temp1, 0x00U, 19U);
::memcpy(temp1, in, 18U);
uint8_t temp2[37U];
encode(temp1, temp2, 148U);
uint32_t n = 0U;
uint32_t index = 0U;
for (uint32_t i = 0U; i < 296U; i++) {
if (i != PUNCTURE_LIST_DATA[index]) {
bool b = READ_BIT1(temp2, i);
WRITE_BIT1(out, n, b);
n++;
} else {
index++;
}
}
}
uint32_t CM17Convolution::decodeLinkSetup(const uint8_t* in, uint8_t* out)
{
assert(in != NULL);
assert(out != NULL);
uint8_t temp[500U];
::memset(temp, 0x00U, 500U);
uint32_t n = 0U;
uint32_t index = 0U;
for (uint32_t i = 0U; i < 368U; i++) {
if (n == PUNCTURE_LIST_LINK_SETUP[index]) {
temp[n++] = 1U;
index++;
}
bool b = READ_BIT1(in, i);
temp[n++] = b ? 2U : 0U;
}
start();
n = 0U;
for (uint32_t i = 0U; i < 244U; i++) {
uint8_t s0 = temp[n++];
uint8_t s1 = temp[n++];
decode(s0, s1);
}
return chainback(out, 240U) - PUNCTURE_LIST_LINK_SETUP_COUNT;
}
uint32_t CM17Convolution::decodeData(const uint8_t* in, uint8_t* out)
{
assert(in != NULL);
assert(out != NULL);
uint8_t temp[300U];
::memset(temp, 0x00U, 300U);
uint32_t n = 0U;
uint32_t index = 0U;
for (uint32_t i = 0U; i < 272U; i++) {
if (n == PUNCTURE_LIST_DATA[index]) {
temp[n++] = 1U;
index++;
}
bool b = READ_BIT1(in, i);
temp[n++] = b ? 2U : 0U;
}
start();
n = 0U;
for (uint32_t i = 0U; i < 148U; i++) {
uint8_t s0 = temp[n++];
uint8_t s1 = temp[n++];
decode(s0, s1);
}
return chainback(out, 144U) - PUNCTURE_LIST_DATA_COUNT;
}
void CM17Convolution::start()
{
::memset(m_metrics1, 0x00U, NUM_OF_STATES * sizeof(uint16_t));
::memset(m_metrics2, 0x00U, NUM_OF_STATES * sizeof(uint16_t));
m_oldMetrics = m_metrics1;
m_newMetrics = m_metrics2;
m_dp = m_decisions;
}
void CM17Convolution::decode(uint8_t s0, uint8_t s1)
{
*m_dp = 0U;
for (uint8_t i = 0U; i < NUM_OF_STATES_D2; i++) {
uint8_t j = i * 2U;
uint16_t metric = std::abs(BRANCH_TABLE1[i] - s0) + std::abs(BRANCH_TABLE2[i] - s1);
uint16_t m0 = m_oldMetrics[i] + metric;
uint16_t m1 = m_oldMetrics[i + NUM_OF_STATES_D2] + (M - metric);
uint8_t decision0 = (m0 >= m1) ? 1U : 0U;
m_newMetrics[j + 0U] = decision0 != 0U ? m1 : m0;
m0 = m_oldMetrics[i] + (M - metric);
m1 = m_oldMetrics[i + NUM_OF_STATES_D2] + metric;
uint8_t decision1 = (m0 >= m1) ? 1U : 0U;
m_newMetrics[j + 1U] = decision1 != 0U ? m1 : m0;
*m_dp |= (uint64_t(decision1) << (j + 1U)) | (uint64_t(decision0) << (j + 0U));
}
++m_dp;
assert((m_dp - m_decisions) <= 300);
uint16_t* tmp = m_oldMetrics;
m_oldMetrics = m_newMetrics;
m_newMetrics = tmp;
}
uint32_t CM17Convolution::chainback(uint8_t* out, uint32_t nBits)
{
assert(out != NULL);
uint32_t state = 0U;
while (nBits-- > 0) {
--m_dp;
uint32_t i = state >> (9 - K);
uint8_t bit = uint8_t(*m_dp >> i) & 1;
state = (bit << 7) | (state >> 1);
WRITE_BIT1(out, nBits, bit != 0U);
}
uint32_t minCost = m_oldMetrics[0];
for (uint32_t i = 0U; i < NUM_OF_STATES; i++) {
if (m_oldMetrics[i] < minCost)
minCost = m_oldMetrics[i];
}
return minCost / (M >> 1);
}
void CM17Convolution::encode(const uint8_t* in, uint8_t* out, uint32_t nBits) const
{
assert(in != NULL);
assert(out != NULL);
assert(nBits > 0U);
uint8_t d1 = 0U, d2 = 0U, d3 = 0U, d4 = 0U;
uint32_t k = 0U;
for (uint32_t i = 0U; i < nBits; i++) {
uint8_t d = READ_BIT1(in, i) ? 1U : 0U;
uint8_t g1 = (d + d3 + d4) & 1;
uint8_t g2 = (d + d1 + d2 + d4) & 1;
d4 = d3;
d3 = d2;
d2 = d1;
d1 = d;
WRITE_BIT1(out, k, g1 != 0U);
k++;
WRITE_BIT1(out, k, g2 != 0U);
k++;
}
}