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289 lines
9.7 KiB
289 lines
9.7 KiB
/**
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* Digital Voice Modem - Host Software
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* GPLv2 Open Source. Use is subject to license terms.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* @package DVM / Host Software
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*
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*/
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/*
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* Copyright (C) 2018-2021 by Bryan Biedenkapp N2PLL
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Defines.h"
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#include "p25/P25Defines.h"
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#include "p25/data/DataBlock.h"
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#include "edac/CRC.h"
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#include "Log.h"
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#include "Utils.h"
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using namespace p25::data;
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using namespace p25;
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#include <cstdio>
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#include <cassert>
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#include <cstring>
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// ---------------------------------------------------------------------------
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// Public Class Members
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// ---------------------------------------------------------------------------
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/// <summary>
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/// Initializes a new instance of the DataBlock class.
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/// </summary>
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DataBlock::DataBlock() :
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m_confirmed(false),
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m_serialNo(0U),
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m_llId(0U),
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m_sap(0U),
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m_trellis(),
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m_fmt(PDU_FMT_CONFIRMED),
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m_headerSap(0U),
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m_data(NULL)
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{
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m_data = new uint8_t[P25_PDU_CONFIRMED_DATA_LENGTH_BYTES];
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}
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/// <summary>
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/// Finalizes a instance of the DataBlock class.
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/// </summary>
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DataBlock::~DataBlock()
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{
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delete[] m_data;
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}
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/// <summary>
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/// Decodes P25 PDU data block.
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/// </summary>
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/// <param name="data"></param>
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/// <param name="header">Instance of the DataHeader class.</param>
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/// <returns>True, if data block was decoded, otherwise false.</returns>
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bool DataBlock::decode(const uint8_t* data, const DataHeader header)
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{
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assert(data != NULL);
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assert(m_data != NULL);
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uint8_t buffer[P25_PDU_CONFIRMED_LENGTH_BYTES];
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::memset(buffer, 0x00U, P25_PDU_CONFIRMED_LENGTH_BYTES);
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m_fmt = header.getFormat();
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m_headerSap = header.getSAP();
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if (m_fmt == PDU_FMT_CONFIRMED) {
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m_confirmed = true;
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bool valid = m_trellis.decode34(data, buffer);
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if (!valid) {
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return false;
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}
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// determine the number of user data bytes
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uint32_t count = P25_PDU_CONFIRMED_DATA_LENGTH_BYTES;
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if (m_serialNo == (header.getBlocksToFollow() - 1) ||
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(m_headerSap == PDU_SAP_EXT_ADDR && m_serialNo == 0U))
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count = P25_PDU_CONFIRMED_DATA_LENGTH_BYTES - 4U;
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// Utils::dump(1U, "PDU Confirmed Data Block", buffer, P25_PDU_CONFIRMED_LENGTH_BYTES);
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m_serialNo = (buffer[0] & 0xFEU) >> 1; // Confirmed Data Serial No.
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uint16_t crc = ((buffer[0] & 0x01U) << 8) + buffer[1]; // CRC-9 Check Sum
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::memset(m_data, 0x00U, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
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// if this is extended addressing and the first block decode the SAP and LLId
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if (m_headerSap == PDU_SAP_EXT_ADDR && m_serialNo == 0U) {
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m_sap = buffer[5U] & 0x3FU; // Service Access Point
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m_llId = (buffer[2U] << 16) + (buffer[3U] << 8) + buffer[4U]; // Logical Link ID
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// re-copy buffer to remove SAP and llId
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for (uint32_t i = 6U; i < count; i++) {
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m_data[i - 6U] = buffer[i]; // Payload Data
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}
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}
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else {
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for (uint32_t i = 2U; i < count; i++) {
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m_data[i - 2U] = buffer[i]; // Payload Data
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}
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}
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// Utils::dump(1U, "PDU Data", m_data, count);
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// compute CRC-9 for the packet
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uint16_t computedCRC = confirmedCRC9(buffer);
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if (crc != computedCRC) {
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LogWarning(LOG_P25, "P25_DUID_PDU, fmt = $%02X, invalid crc = $%04X != $%04X (computed)", m_fmt, crc, computedCRC);
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}
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}
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else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP)) {
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m_confirmed = false;
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bool valid = m_trellis.decode12(data, buffer);
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if (!valid) {
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return false;
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}
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// Utils::dump(1U, "PDU Unconfirmed Data Block", buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
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for (uint32_t i = 0U; i < P25_PDU_UNCONFIRMED_LENGTH_BYTES; i++) {
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m_data[i] = buffer[i]; // Payload Data
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}
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}
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else {
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LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
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}
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return true;
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}
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/// <summary>
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/// Encodes a P25 PDU data block.
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/// </summary>
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/// <param name="data">Buffer to encode data block to.</param>
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void DataBlock::encode(uint8_t* data)
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{
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assert(data != NULL);
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assert(m_data != NULL);
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if ((m_fmt == PDU_FMT_CONFIRMED) || (m_fmt == PDU_FMT_RSP && m_confirmed)) {
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uint8_t buffer[P25_PDU_CONFIRMED_LENGTH_BYTES];
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::memset(buffer, 0x00U, P25_PDU_CONFIRMED_LENGTH_BYTES);
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buffer[0U] = ((m_serialNo & 0xFEU) << 1); // Confirmed Data Serial No.
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// if this is extended addressing and the first block decode the SAP and LLId
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if (m_headerSap == PDU_SAP_EXT_ADDR && m_serialNo == 0U) {
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buffer[5U] = m_sap & 0x3FU; // Service Access Point
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buffer[2U] = (m_llId >> 16) & 0xFFU; // Logical Link ID
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buffer[3U] = (m_llId >> 8) & 0xFFU;
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buffer[4U] = (m_llId >> 0) & 0xFFU;
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::memcpy(buffer + 6U, m_data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES - 4U);
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}
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else {
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::memcpy(buffer + 2U, m_data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
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}
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uint16_t crc = confirmedCRC9(buffer);
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buffer[0U] = buffer[0U] + ((crc >> 8) & 0x01U); // CRC-9 Check Sum (b8)
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buffer[1U] = (crc & 0xFFU); // CRC-9 Check Sum (b0 - b7)
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// Utils::dump(1U, "PDU Confirmed Data Block", buffer, P25_PDU_CONFIRMED_LENGTH_BYTES);
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m_trellis.encode34(buffer, data);
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}
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else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP && !m_confirmed)) {
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uint8_t buffer[P25_PDU_UNCONFIRMED_LENGTH_BYTES];
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::memset(buffer, 0x00U, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
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::memcpy(buffer, m_data, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
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// Utils::dump(1U, "PDU Unconfirmed Data Block", buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
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m_trellis.encode12(buffer, data);
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}
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else {
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LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
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return;
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}
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}
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/// <summary>Sets the data format.</summary>
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/// <param name="fmt"></param>
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void DataBlock::setFormat(const uint8_t fmt)
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{
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m_fmt = fmt;
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}
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/// <summary>Sets the data format from the data header.</summary>
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/// <param name="header"></param>
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void DataBlock::setFormat(const DataHeader header)
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{
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m_fmt = header.getFormat();
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if (m_fmt == PDU_FMT_CONFIRMED) {
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m_confirmed = true;
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}
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else {
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m_confirmed = false;
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}
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}
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/// <summary>Gets the data format.</summary>
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/// <returns></returns>
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uint8_t DataBlock::getFormat() const
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{
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return m_fmt;
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}
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/// <summary>Sets the raw data stored in the data block.</summary>
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/// <param name="buffer"></param>
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void DataBlock::setData(const uint8_t* buffer)
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{
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assert(buffer != NULL);
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assert(m_data != NULL);
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if ((m_fmt == PDU_FMT_CONFIRMED) || (m_fmt == PDU_FMT_RSP && m_confirmed)) {
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::memcpy(m_data, buffer, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
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}
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else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP && !m_confirmed)) {
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::memcpy(m_data, buffer, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
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}
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else {
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LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
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}
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}
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/// <summary>Gets the raw data stored in the data block.</summary>
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/// <returns></returns>
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uint32_t DataBlock::getData(uint8_t* buffer) const
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{
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assert(buffer != NULL);
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assert(m_data != NULL);
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if ((m_fmt == PDU_FMT_CONFIRMED) || (m_fmt == PDU_FMT_RSP && m_confirmed)) {
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::memcpy(buffer, m_data, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES);
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return P25_PDU_CONFIRMED_DATA_LENGTH_BYTES;
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}
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else if ((m_fmt == PDU_FMT_UNCONFIRMED) || (m_fmt == PDU_FMT_RSP && !m_confirmed)) {
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::memcpy(buffer, m_data, P25_PDU_UNCONFIRMED_LENGTH_BYTES);
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return P25_PDU_UNCONFIRMED_LENGTH_BYTES;
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}
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else {
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LogError(LOG_P25, "unknown FMT value in P25_DUID_PDU, fmt = $%02X", m_fmt);
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return 0U;
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}
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}
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// ---------------------------------------------------------------------------
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// Private Class Members
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// ---------------------------------------------------------------------------
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/// <summary>
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///
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/// </summary>
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/// <param name="buffer"></param>
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uint16_t DataBlock::confirmedCRC9(const uint8_t* buffer)
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{
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// generate 135-bit CRC buffer
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uint8_t* crcBuffer = new uint8_t[17U];
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::memset(crcBuffer, 0x00U, 17U);
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Utils::setBitRange(buffer, crcBuffer, 0U, 7U);
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uint8_t* data = new uint8_t[P25_PDU_CONFIRMED_DATA_LENGTH_BYTES];
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Utils::getBitRange(buffer, data, 16U, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES * 8);
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Utils::setBitRange(data, crcBuffer, 7U, P25_PDU_CONFIRMED_DATA_LENGTH_BYTES * 8);
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return edac::CRC::crc9(crcBuffer, 135U);
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}
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