81 lines
1.9 KiB
C++
81 lines
1.9 KiB
C++
/*
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* Copyright (C) 2016 by Jonathan Naylor G4KLX
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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 "P25NID.h"
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#include "P25Defines.h"
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#include <cstdio>
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#include <cassert>
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const unsigned char BIT_MASK_TABLE[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
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#define WRITE_BIT(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
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#define READ_BIT(p,i) (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
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CP25NID::CP25NID() :
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m_duid(0U),
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m_nac(0U)
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{
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}
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CP25NID::~CP25NID()
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{
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}
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void CP25NID::process(unsigned char* data)
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{
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assert(data != NULL);
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unsigned char nid[P25_NID_LENGTH_BYTES];
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unsigned int n = 0U;
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for (unsigned int offset = 48U; offset < 114U; offset++) {
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if (offset != P25_SS0_START && offset != P25_SS1_START) {
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bool b = READ_BIT(data, offset);
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WRITE_BIT(nid, n, b);
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n++;
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}
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}
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// XXX Process FEC here
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m_duid = nid[1U] & 0x0FU;
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m_nac = (nid[0U] << 4) & 0xFF0U;
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m_nac |= (nid[1U] >> 4) & 0x00FU;
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n = 0U;
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for (unsigned int offset = 48U; offset < 114U; offset++) {
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if (offset != P25_SS0_START && offset != P25_SS1_START) {
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bool b = READ_BIT(nid, n);
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WRITE_BIT(data, offset, b);
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n++;
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}
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}
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}
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unsigned char CP25NID::getDUID() const
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{
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return m_duid;
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}
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unsigned int CP25NID::getNAC() const
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{
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return m_nac;
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}
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