mirror of
https://github.com/f4exb/sdrangel.git
synced 2026-03-31 20:25:38 -04:00
683 lines
23 KiB
C++
683 lines
23 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2020 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
|
|
// //
|
|
// Inspired by: https://github.com/myriadrf/LoRa-SDR //
|
|
// //
|
|
// 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 as version 3 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 V3 for more details. //
|
|
// //
|
|
// You should have received a copy of the GNU General Public License //
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
|
|
///////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#include <algorithm>
|
|
|
|
#include "meshtasticdemodsettings.h"
|
|
#include "meshtasticdemoddecoderlora.h"
|
|
|
|
void MeshtasticDemodDecoderLoRa::decodeHeader(
|
|
const std::vector<unsigned short>& inSymbols,
|
|
unsigned int headerNbSymbolBits,
|
|
bool& hasCRC,
|
|
unsigned int& nbParityBits,
|
|
unsigned int& packetLength,
|
|
int& headerParityStatus,
|
|
bool& headerCRCStatus
|
|
)
|
|
{
|
|
// with header (H: header 8-bit codeword P: payload-8 bit codeword):
|
|
// nbSymbolBits = 5 |H|H|H|H|H| codewords => 8 symbols (always) : static headerSymbols = 8
|
|
// nbSymbolBits = 7 |H|H|H|H|H|P|P|
|
|
// without header (P: payload 8-bit codeword):
|
|
// nbSymbolBits = 5 |P|P|P|P|P| codewords => 8 symbols (always)
|
|
// nbSymbolBits = 7 |P|P|P|P|P|P|P|
|
|
// Actual header is always represented with 5 8-bit codewords : static headerCodewords = 5
|
|
// These 8-bit codewords are encoded with Hamming(4,8) FEC : static headerParityBits = 4
|
|
|
|
std::vector<uint16_t> symbols(headerSymbols);
|
|
std::copy(inSymbols.begin(), inSymbols.begin() + headerSymbols, symbols.begin());
|
|
|
|
//gray encode
|
|
for (auto &sym : symbols) {
|
|
sym = binaryToGray16(sym);
|
|
}
|
|
|
|
std::vector<uint8_t> codewords(headerNbSymbolBits);
|
|
|
|
// Header symbols de-interleave thus headerSymbols (8) symbols into nbSymbolBits (5..12) codewords using header FEC (4/8)
|
|
diagonalDeinterleaveSx(symbols.data(), headerSymbols, codewords.data(), headerNbSymbolBits, headerParityBits);
|
|
|
|
bool error = false;
|
|
bool bad = false;
|
|
uint8_t bytes[3];
|
|
|
|
// decode actual header inside 8-bit codewords header with 4/8 FEC (5 first codewords)
|
|
bytes[0] = decodeHamming84sx(codewords[1], error, bad) & 0xf;
|
|
bytes[0] |= decodeHamming84sx(codewords[0], error, bad) << 4; // length
|
|
|
|
bytes[1] = decodeHamming84sx(codewords[2], error, bad) & 0xf; // coding rate and crc enable
|
|
|
|
bytes[2] = decodeHamming84sx(codewords[4], error, bad) & 0xf;
|
|
bytes[2] |= decodeHamming84sx(codewords[3], error, bad) << 4; // checksum
|
|
|
|
bytes[2] ^= headerChecksum(bytes);
|
|
|
|
if (bad)
|
|
{
|
|
headerParityStatus = (int) MeshtasticDemodSettings::ParityError;
|
|
}
|
|
else
|
|
{
|
|
if (error) {
|
|
headerParityStatus = (int) MeshtasticDemodSettings::ParityCorrected;
|
|
} else {
|
|
headerParityStatus = (int) MeshtasticDemodSettings::ParityOK;
|
|
}
|
|
|
|
if (((bytes[2] & 0x1F) != 0) || (bytes[0] == 0)) {
|
|
headerCRCStatus = false;
|
|
} else {
|
|
headerCRCStatus = true;
|
|
}
|
|
}
|
|
|
|
hasCRC = (bytes[1] & 1) != 0;
|
|
nbParityBits = (bytes[1] >> 1) & 0x7;
|
|
packetLength = bytes[0];
|
|
}
|
|
|
|
void MeshtasticDemodDecoderLoRa::decodeBytes(
|
|
QByteArray& inBytes,
|
|
const std::vector<unsigned short>& inSymbols,
|
|
unsigned int payloadNbSymbolBits,
|
|
unsigned int headerNbSymbolBits,
|
|
bool hasHeader,
|
|
bool& hasCRC,
|
|
unsigned int& nbParityBits,
|
|
unsigned int& packetLength,
|
|
bool& earlyEOM,
|
|
int& headerParityStatus,
|
|
bool& headerCRCStatus,
|
|
int& payloadParityStatus,
|
|
bool& payloadCRCStatus
|
|
)
|
|
{
|
|
payloadCRCStatus = false;
|
|
|
|
// need at least a header (8 symbols of 8 bit codewords) whether an actual header is sent or not
|
|
if (inSymbols.size() < headerSymbols)
|
|
{
|
|
qDebug("MeshtasticDemodDecoderLoRa::decodeBytes: need at least %u symbols for header", headerSymbols);
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
else
|
|
{
|
|
earlyEOM = false;
|
|
}
|
|
|
|
if (hasHeader)
|
|
{
|
|
if (headerNbSymbolBits < headerCodewords)
|
|
{
|
|
qDebug("MeshtasticDemodDecoderLoRa::decodeBytes: invalid header symbol bits: %u", headerNbSymbolBits);
|
|
earlyEOM = true;
|
|
headerCRCStatus = false;
|
|
return;
|
|
}
|
|
|
|
decodeHeader(
|
|
inSymbols,
|
|
headerNbSymbolBits,
|
|
hasCRC,
|
|
nbParityBits,
|
|
packetLength,
|
|
headerParityStatus,
|
|
headerCRCStatus
|
|
);
|
|
|
|
// Match gr-lora_sdr behavior: on explicit-header checksum failure,
|
|
// do not continue payload decoding for this frame attempt.
|
|
if (!headerCRCStatus)
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
}
|
|
|
|
qDebug("MeshtasticDemodDecoderLoRa::decodeBytes: crc: %s nbParityBits: %u packetLength: %u payloadSFbits: %u headerSFbits: %u",
|
|
hasCRC ? "on": "off", nbParityBits, packetLength, payloadNbSymbolBits, headerNbSymbolBits);
|
|
|
|
if (nbParityBits > 4)
|
|
{
|
|
qDebug("MeshtasticDemodDecoderLoRa::decodeBytes: invalid parity bits in header: %u", nbParityBits);
|
|
earlyEOM = true;
|
|
headerCRCStatus = false;
|
|
return;
|
|
}
|
|
|
|
const unsigned int payloadBlockSymbols = 4 + nbParityBits;
|
|
unsigned int numSymbols = 0;
|
|
unsigned int numCodewords = 0;
|
|
|
|
if (hasHeader)
|
|
{
|
|
const unsigned int payloadSymbols = inSymbols.size() > headerSymbols
|
|
? static_cast<unsigned int>(inSymbols.size() - headerSymbols)
|
|
: 0U;
|
|
const unsigned int payloadBlocks = payloadSymbols / payloadBlockSymbols;
|
|
|
|
numSymbols = headerSymbols + payloadBlocks * payloadBlockSymbols;
|
|
numCodewords = headerNbSymbolBits + payloadBlocks * payloadNbSymbolBits;
|
|
}
|
|
else
|
|
{
|
|
const unsigned int payloadBlocks = static_cast<unsigned int>(inSymbols.size()) / payloadBlockSymbols;
|
|
numSymbols = payloadBlocks * payloadBlockSymbols;
|
|
numCodewords = payloadBlocks * payloadNbSymbolBits;
|
|
}
|
|
|
|
if (numSymbols < headerSymbols)
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
std::vector<uint16_t> symbols(numSymbols);
|
|
std::copy_n(inSymbols.begin(), numSymbols, symbols.begin());
|
|
|
|
//gray encode, when SF > PPM, depad the LSBs with rounding
|
|
for (auto &sym : symbols) {
|
|
sym = binaryToGray16(sym);
|
|
}
|
|
|
|
std::vector<uint8_t> codewords(numCodewords);
|
|
|
|
// deinterleave / dewhiten the symbols into codewords
|
|
unsigned int sOfs = 0;
|
|
unsigned int cOfs = 0;
|
|
|
|
// The first 8 LoRa symbols are always protected with 4/8 FEC.
|
|
// In explicit-header mode this first block is interleaved over SF-2 bits
|
|
// (header + first payload nibbles), while the remaining payload uses the
|
|
// configured payload symbol width.
|
|
if (hasHeader)
|
|
{
|
|
diagonalDeinterleaveSx(symbols.data(), headerSymbols, codewords.data(), headerNbSymbolBits, headerParityBits);
|
|
|
|
cOfs = headerNbSymbolBits;
|
|
sOfs = headerSymbols;
|
|
|
|
if (numSymbols > sOfs)
|
|
{
|
|
diagonalDeinterleaveSx(symbols.data() + sOfs, numSymbols - sOfs, codewords.data() + cOfs, payloadNbSymbolBits, nbParityBits);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
diagonalDeinterleaveSx(symbols.data(), numSymbols, codewords.data(), payloadNbSymbolBits, nbParityBits);
|
|
}
|
|
|
|
// Now we have nbSymbolBits 8-bit codewords (4/8 FEC) possibly containing the actual header followed by the rest of payload codewords with their own FEC (4/5..4/8)
|
|
|
|
std::vector<uint8_t> bytes((codewords.size()+1) / 2);
|
|
unsigned int dOfs = 0;
|
|
cOfs = 0;
|
|
|
|
// Payload byte count plus optional outer CRC bytes; include header bytes
|
|
// only for explicit-header mode.
|
|
unsigned int dataLength = packetLength + (hasCRC ? 2 : 0);
|
|
if (hasHeader) {
|
|
dataLength += 3;
|
|
}
|
|
|
|
if (hasHeader)
|
|
{
|
|
cOfs = headerCodewords;
|
|
dOfs = 6;
|
|
}
|
|
else
|
|
{
|
|
cOfs = 0;
|
|
dOfs = 0;
|
|
}
|
|
|
|
if (dataLength > bytes.size())
|
|
{
|
|
qDebug("MeshtasticDemodDecoderLoRa::decodeBytes: not enough data %lu vs %u", bytes.size(), dataLength);
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
// decode the rest of the payload inside 8-bit codewords header with 4/8 FEC
|
|
bool error = false;
|
|
bool bad = false;
|
|
|
|
const unsigned int firstBlockCodewords = hasHeader ? headerNbSymbolBits : payloadNbSymbolBits;
|
|
|
|
for (; cOfs < firstBlockCodewords; cOfs++, dOfs++)
|
|
{
|
|
if (dOfs % 2 == 1) {
|
|
bytes[dOfs/2] |= decodeHamming84sx(codewords[cOfs], error, bad) << 4;
|
|
} else {
|
|
bytes[dOfs/2] = decodeHamming84sx(codewords[cOfs], error, bad) & 0xf;
|
|
}
|
|
}
|
|
|
|
if (dOfs % 2 == 1) // decode the start of the payload codewords with their own FEC when not on an even boundary
|
|
{
|
|
if (nbParityBits == 1) {
|
|
bytes[dOfs/2] |= checkParity54(codewords[cOfs++], error) << 4;
|
|
} else if (nbParityBits == 2) {
|
|
bytes[dOfs/2] |= checkParity64(codewords[cOfs++], error) << 4;
|
|
} else if (nbParityBits == 3){
|
|
bytes[dOfs/2] |= decodeHamming74sx(codewords[cOfs++], error) << 4;
|
|
} else if (nbParityBits == 4){
|
|
bytes[dOfs/2] |= decodeHamming84sx(codewords[cOfs++], error, bad) << 4;
|
|
} else {
|
|
bytes[dOfs/2] |= codewords[cOfs++] << 4;
|
|
}
|
|
|
|
dOfs++;
|
|
}
|
|
|
|
dOfs /= 2;
|
|
|
|
// decode the rest of the payload codewords with their own FEC
|
|
|
|
if (nbParityBits == 1)
|
|
{
|
|
for (unsigned int i = dOfs; i < dataLength; i++)
|
|
{
|
|
bytes[i] = checkParity54(codewords[cOfs++],error);
|
|
bytes[i] |= checkParity54(codewords[cOfs++], error) << 4;
|
|
}
|
|
}
|
|
else if (nbParityBits == 2)
|
|
{
|
|
for (unsigned int i = dOfs; i < dataLength; i++)
|
|
{
|
|
bytes[i] = checkParity64(codewords[cOfs++], error);
|
|
bytes[i] |= checkParity64(codewords[cOfs++],error) << 4;
|
|
}
|
|
}
|
|
else if (nbParityBits == 3)
|
|
{
|
|
for (unsigned int i = dOfs; i < dataLength; i++)
|
|
{
|
|
bytes[i] = decodeHamming74sx(codewords[cOfs++], error) & 0xf;
|
|
bytes[i] |= decodeHamming74sx(codewords[cOfs++], error) << 4;
|
|
}
|
|
}
|
|
else if (nbParityBits == 4)
|
|
{
|
|
for (unsigned int i = dOfs; i < dataLength; i++)
|
|
{
|
|
bytes[i] = decodeHamming84sx(codewords[cOfs++], error, bad) & 0xf;
|
|
bytes[i] |= decodeHamming84sx(codewords[cOfs++], error, bad) << 4;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
for (unsigned int i = dOfs; i < dataLength; i++)
|
|
{
|
|
bytes[i] = codewords[cOfs++] & 0xf;
|
|
bytes[i] |= codewords[cOfs++] << 4;
|
|
}
|
|
}
|
|
|
|
// LoRa payload dewhitening is applied after FEC decode and excludes the CRC bytes.
|
|
const unsigned int payloadByteOfs = hasHeader ? 3U : 0U;
|
|
if (packetLength > 0U && (payloadByteOfs + packetLength) <= bytes.size()) {
|
|
dewhitenPayloadBytes(bytes.data() + payloadByteOfs, packetLength);
|
|
}
|
|
|
|
if (bad) {
|
|
payloadParityStatus = (int) MeshtasticDemodSettings::ParityError;
|
|
} else if (error) {
|
|
payloadParityStatus = (int) MeshtasticDemodSettings::ParityCorrected;
|
|
} else {
|
|
payloadParityStatus = (int) MeshtasticDemodSettings::ParityOK;
|
|
}
|
|
|
|
// finalization:
|
|
// adjust offsets dpending on header and CRC presence
|
|
// compute and verify payload CRC if present
|
|
|
|
if (hasHeader)
|
|
{
|
|
dOfs = 3; // skip header
|
|
dataLength -= 3; // remove header
|
|
|
|
if (hasCRC) // always compute crc if present skipping the header
|
|
{
|
|
if ((packetLength >= 2U) && ((dOfs + packetLength + 2U) <= bytes.size()))
|
|
{
|
|
// Match gr-lora_sdr crc_verif:
|
|
// crc16(first pay_len-2 bytes) XOR last 2 bytes inside payload
|
|
// compare against trailing CRC bytes.
|
|
uint16_t crc = crc16gr(bytes.data() + dOfs, packetLength - 2U);
|
|
crc = static_cast<uint16_t>(crc ^ static_cast<uint8_t>(bytes[dOfs + packetLength - 1U]));
|
|
crc = static_cast<uint16_t>(crc ^ (static_cast<uint16_t>(static_cast<uint8_t>(bytes[dOfs + packetLength - 2U])) << 8));
|
|
const uint16_t packetCRC = static_cast<uint16_t>(static_cast<uint8_t>(bytes[dOfs + packetLength]))
|
|
| (static_cast<uint16_t>(static_cast<uint8_t>(bytes[dOfs + packetLength + 1U])) << 8);
|
|
|
|
payloadCRCStatus = (crc == packetCRC);
|
|
}
|
|
else
|
|
{
|
|
payloadCRCStatus = false;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
payloadCRCStatus = true;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
dOfs = 0; // no header to skip
|
|
|
|
if (hasCRC)
|
|
{
|
|
if ((packetLength >= 2U) && ((packetLength + 2U) <= bytes.size()))
|
|
{
|
|
uint16_t crc = crc16gr(bytes.data(), packetLength - 2U);
|
|
crc = static_cast<uint16_t>(crc ^ static_cast<uint8_t>(bytes[packetLength - 1U]));
|
|
crc = static_cast<uint16_t>(crc ^ (static_cast<uint16_t>(static_cast<uint8_t>(bytes[packetLength - 2U])) << 8));
|
|
const uint16_t packetCRC = static_cast<uint16_t>(static_cast<uint8_t>(bytes[packetLength]))
|
|
| (static_cast<uint16_t>(static_cast<uint8_t>(bytes[packetLength + 1U])) << 8);
|
|
payloadCRCStatus = (crc == packetCRC);
|
|
}
|
|
else
|
|
{
|
|
payloadCRCStatus = false;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
payloadCRCStatus = true;
|
|
}
|
|
}
|
|
|
|
inBytes.resize(packetLength);
|
|
std::copy(bytes.data() + dOfs, bytes.data() + dOfs + packetLength, inBytes.data());
|
|
}
|
|
|
|
void MeshtasticDemodDecoderLoRa::decodeBytesSoft(
|
|
QByteArray& inBytes,
|
|
const std::vector<std::vector<float>>& inMagnitudes,
|
|
const std::vector<unsigned short>& inSymbols,
|
|
unsigned int spreadFactor,
|
|
unsigned int bandwidth,
|
|
unsigned int payloadNbSymbolBits,
|
|
unsigned int headerNbSymbolBits,
|
|
bool hasHeader,
|
|
bool& hasCRC,
|
|
unsigned int& nbParityBits,
|
|
unsigned int& packetLength,
|
|
bool& earlyEOM,
|
|
int& headerParityStatus,
|
|
bool& headerCRCStatus,
|
|
int& payloadParityStatus,
|
|
bool& payloadCRCStatus
|
|
)
|
|
{
|
|
payloadCRCStatus = false;
|
|
payloadParityStatus = (int) MeshtasticDemodSettings::ParityUndefined;
|
|
|
|
if (inSymbols.size() < headerSymbols)
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
else
|
|
{
|
|
earlyEOM = false;
|
|
}
|
|
|
|
if (hasHeader)
|
|
{
|
|
if (headerNbSymbolBits < headerCodewords)
|
|
{
|
|
earlyEOM = true;
|
|
headerCRCStatus = false;
|
|
return;
|
|
}
|
|
|
|
decodeHeader(
|
|
inSymbols,
|
|
headerNbSymbolBits,
|
|
hasCRC,
|
|
nbParityBits,
|
|
packetLength,
|
|
headerParityStatus,
|
|
headerCRCStatus
|
|
);
|
|
|
|
if (!headerCRCStatus)
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if ((nbParityBits < 1U) || (nbParityBits > 4U))
|
|
{
|
|
earlyEOM = true;
|
|
headerCRCStatus = false;
|
|
return;
|
|
}
|
|
|
|
const unsigned int payloadBlockSymbols = 4U + nbParityBits;
|
|
unsigned int numSymbols = 0U;
|
|
|
|
if (hasHeader)
|
|
{
|
|
const unsigned int payloadSymbols = inSymbols.size() > headerSymbols
|
|
? static_cast<unsigned int>(inSymbols.size() - headerSymbols)
|
|
: 0U;
|
|
const unsigned int payloadBlocks = payloadSymbols / payloadBlockSymbols;
|
|
numSymbols = headerSymbols + payloadBlocks * payloadBlockSymbols;
|
|
}
|
|
else
|
|
{
|
|
const unsigned int payloadBlocks = static_cast<unsigned int>(inSymbols.size()) / payloadBlockSymbols;
|
|
numSymbols = payloadBlocks * payloadBlockSymbols;
|
|
}
|
|
|
|
if ((numSymbols < headerSymbols) || (inMagnitudes.size() < numSymbols))
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
const unsigned int N = 1U << spreadFactor;
|
|
const bool ldro = ((1U << spreadFactor) * 1000.0 / static_cast<double>(std::max(1U, bandwidth))) > 16.0;
|
|
std::vector<std::vector<float>> llrs(numSymbols, std::vector<float>(spreadFactor, 0.0f));
|
|
|
|
for (unsigned int symIdx = 0; symIdx < numSymbols; symIdx++)
|
|
{
|
|
const std::vector<float>& mags = inMagnitudes[symIdx];
|
|
|
|
if (mags.size() < N)
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
const bool isHeaderSym = hasHeader && (symIdx < headerSymbols);
|
|
const bool ldroSym = (!isHeaderSym) && ldro;
|
|
const unsigned int symbolDiv = (isHeaderSym || ldroSym) ? 4U : 1U;
|
|
|
|
for (unsigned int bit = 0; bit < spreadFactor; bit++)
|
|
{
|
|
float maxX1 = std::numeric_limits<float>::lowest();
|
|
float maxX0 = std::numeric_limits<float>::lowest();
|
|
|
|
for (unsigned int n = 0; n < N; n++)
|
|
{
|
|
unsigned int s = static_cast<unsigned int>(modInt(static_cast<int>(n) - 1, static_cast<int>(N)));
|
|
s /= symbolDiv;
|
|
s = s ^ (s >> 1U);
|
|
const float v = mags[n];
|
|
|
|
if ((s & (1U << bit)) != 0U) {
|
|
maxX1 = std::max(maxX1, v);
|
|
} else {
|
|
maxX0 = std::max(maxX0, v);
|
|
}
|
|
}
|
|
|
|
if (!std::isfinite(maxX1)) { maxX1 = 0.0f; }
|
|
if (!std::isfinite(maxX0)) { maxX0 = 0.0f; }
|
|
llrs[symIdx][spreadFactor - 1U - bit] = maxX1 - maxX0;
|
|
}
|
|
}
|
|
|
|
auto decodeSoftBlock = [&llrs, spreadFactor](unsigned int symOfs, unsigned int cwLen, unsigned int sfApp, unsigned int crApp, std::vector<uint8_t>& nibbles) {
|
|
if (sfApp == 0U) {
|
|
return false;
|
|
}
|
|
|
|
std::vector<std::vector<float>> interBin(cwLen, std::vector<float>(sfApp, 0.0f));
|
|
std::vector<std::vector<float>> deinterBin(sfApp, std::vector<float>(cwLen, 0.0f));
|
|
|
|
for (unsigned int i = 0; i < cwLen; i++)
|
|
{
|
|
const std::vector<float>& symLlr = llrs[symOfs + i];
|
|
const unsigned int start = (spreadFactor > sfApp) ? (spreadFactor - sfApp) : 0U;
|
|
|
|
for (unsigned int j = 0; j < sfApp; j++) {
|
|
interBin[i][j] = symLlr[start + j];
|
|
}
|
|
}
|
|
|
|
for (unsigned int i = 0; i < cwLen; i++)
|
|
{
|
|
for (unsigned int j = 0; j < sfApp; j++)
|
|
{
|
|
const unsigned int row = static_cast<unsigned int>(modInt(static_cast<int>(i) - static_cast<int>(j) - 1, static_cast<int>(sfApp)));
|
|
deinterBin[row][i] = interBin[i][j];
|
|
}
|
|
}
|
|
|
|
for (unsigned int row = 0; row < sfApp; row++) {
|
|
nibbles.push_back(decodeCodewordSoft(deinterBin[row], crApp));
|
|
}
|
|
|
|
return true;
|
|
};
|
|
|
|
std::vector<uint8_t> nibbles;
|
|
nibbles.reserve((packetLength + (hasCRC ? 2U : 0U) * 2U) + 16U);
|
|
unsigned int symOfs = 0U;
|
|
|
|
if (hasHeader)
|
|
{
|
|
if (symOfs + headerSymbols > numSymbols) {
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
if (!decodeSoftBlock(symOfs, 8U, headerNbSymbolBits, 4U, nibbles)) {
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
symOfs += headerSymbols;
|
|
}
|
|
|
|
while (symOfs + payloadBlockSymbols <= numSymbols)
|
|
{
|
|
if (!decodeSoftBlock(symOfs, payloadBlockSymbols, payloadNbSymbolBits, nbParityBits, nibbles)) {
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
symOfs += payloadBlockSymbols;
|
|
}
|
|
|
|
const unsigned int dataByteLen = packetLength + (hasCRC ? 2U : 0U);
|
|
const unsigned int nibbleOfs = hasHeader ? 5U : 0U;
|
|
const unsigned int neededNibbles = nibbleOfs + dataByteLen * 2U;
|
|
|
|
if (nibbles.size() < neededNibbles)
|
|
{
|
|
earlyEOM = true;
|
|
return;
|
|
}
|
|
|
|
std::vector<uint8_t> bytes(dataByteLen, 0U);
|
|
|
|
for (unsigned int i = 0; i < dataByteLen; i++)
|
|
{
|
|
const uint8_t low = nibbles[nibbleOfs + i * 2U] & 0x0FU;
|
|
const uint8_t high = nibbles[nibbleOfs + i * 2U + 1U] & 0x0FU;
|
|
bytes[i] = static_cast<uint8_t>(low | (high << 4));
|
|
}
|
|
|
|
if (packetLength > 0U) {
|
|
dewhitenPayloadBytes(bytes.data(), packetLength);
|
|
}
|
|
|
|
if (hasCRC)
|
|
{
|
|
if ((packetLength >= 2U) && (dataByteLen >= packetLength + 2U))
|
|
{
|
|
uint16_t crc = crc16gr(bytes.data(), packetLength - 2U);
|
|
crc = static_cast<uint16_t>(crc ^ bytes[packetLength - 1U]);
|
|
crc = static_cast<uint16_t>(crc ^ (static_cast<uint16_t>(bytes[packetLength - 2U]) << 8));
|
|
const uint16_t packetCRC = static_cast<uint16_t>(bytes[packetLength])
|
|
| (static_cast<uint16_t>(bytes[packetLength + 1U]) << 8);
|
|
payloadCRCStatus = (crc == packetCRC);
|
|
}
|
|
else
|
|
{
|
|
payloadCRCStatus = false;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
payloadCRCStatus = true;
|
|
}
|
|
|
|
inBytes.resize(packetLength);
|
|
std::copy(bytes.begin(), bytes.begin() + packetLength, inBytes.begin());
|
|
}
|
|
|
|
void MeshtasticDemodDecoderLoRa::getCodingMetrics(
|
|
unsigned int payloadNbSymbolBits,
|
|
unsigned int headerNbSymbolBits,
|
|
unsigned int nbParityBits,
|
|
unsigned int packetLength,
|
|
bool hasHeader,
|
|
bool hasCRC,
|
|
unsigned int& numSymbols,
|
|
unsigned int& numCodewords
|
|
)
|
|
{
|
|
if (hasHeader)
|
|
{
|
|
const unsigned int payloadNibbles = (packetLength + (hasCRC ? 2 : 0)) * 2;
|
|
const unsigned int firstPayloadNibbles = headerNbSymbolBits > headerCodewords ? (headerNbSymbolBits - headerCodewords) : 0;
|
|
const unsigned int remainingPayloadNibbles = payloadNibbles > firstPayloadNibbles ? (payloadNibbles - firstPayloadNibbles) : 0;
|
|
const unsigned int payloadBlocks = remainingPayloadNibbles > 0 ? roundUp(remainingPayloadNibbles, payloadNbSymbolBits) / payloadNbSymbolBits : 0;
|
|
|
|
numCodewords = headerNbSymbolBits + payloadBlocks * payloadNbSymbolBits;
|
|
numSymbols = headerSymbols + payloadBlocks * (4 + nbParityBits);
|
|
}
|
|
else
|
|
{
|
|
numCodewords = roundUp((packetLength + (hasCRC ? 2 : 0)) * 2, payloadNbSymbolBits);
|
|
numSymbols = headerSymbols + (numCodewords / payloadNbSymbolBits - 1) * (4 + nbParityBits);
|
|
}
|
|
}
|