340 lines
8.4 KiB
C++
340 lines
8.4 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 "P25Audio.h"
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#include "P25Utils.h"
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#include "Golay24128.h"
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#include "Hamming.h"
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#include <cstdio>
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#include <cassert>
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const unsigned int IMBE_INTERLEAVE[] = {
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0, 7, 12, 19, 24, 31, 36, 43, 48, 55, 60, 67, 72, 79, 84, 91, 96, 103, 108, 115, 120, 127, 132, 139,
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1, 6, 13, 18, 25, 30, 37, 42, 49, 54, 61, 66, 73, 78, 85, 90, 97, 102, 109, 114, 121, 126, 133, 138,
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2, 9, 14, 21, 26, 33, 38, 45, 50, 57, 62, 69, 74, 81, 86, 93, 98, 105, 110, 117, 122, 129, 134, 141,
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3, 8, 15, 20, 27, 32, 39, 44, 51, 56, 63, 68, 75, 80, 87, 92, 99, 104, 111, 116, 123, 128, 135, 140,
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4, 11, 16, 23, 28, 35, 40, 47, 52, 59, 64, 71, 76, 83, 88, 95, 100, 107, 112, 119, 124, 131, 136, 143,
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5, 10, 17, 22, 29, 34, 41, 46, 53, 58, 65, 70, 77, 82, 89, 94, 101, 106, 113, 118, 125, 130, 137, 142};
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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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CP25Audio::CP25Audio() :
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m_fec()
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{
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}
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CP25Audio::~CP25Audio()
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{
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}
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unsigned int CP25Audio::process(unsigned char* data)
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{
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assert(data != NULL);
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unsigned int errs = 0U;
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unsigned char imbe[18U];
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CP25Utils::decode(data, imbe, 114U, 262U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 114U, 262U);
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CP25Utils::decode(data, imbe, 262U, 410U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 262U, 410U);
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CP25Utils::decode(data, imbe, 452U, 600U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 452U, 600U);
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CP25Utils::decode(data, imbe, 640U, 788U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 640U, 788U);
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CP25Utils::decode(data, imbe, 830U, 978U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 830U, 978U);
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CP25Utils::decode(data, imbe, 1020U, 1168U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 1020U, 1168U);
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CP25Utils::decode(data, imbe, 1208U, 1356U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 1208U, 1356U);
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CP25Utils::decode(data, imbe, 1398U, 1546U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 1398U, 1546U);
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CP25Utils::decode(data, imbe, 1578U, 1726U);
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errs += m_fec.regenerateIMBE(imbe);
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CP25Utils::encode(imbe, data, 1578U, 1726U);
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return errs;
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}
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void CP25Audio::decode(const unsigned char* data, unsigned char* imbe, unsigned int n)
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{
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assert(data != NULL);
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assert(imbe != NULL);
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unsigned char temp[18U];
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switch (n) {
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case 0U:
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CP25Utils::decode(data, temp, 114U, 262U);
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break;
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case 1U:
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CP25Utils::decode(data, temp, 262U, 410U);
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break;
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case 2U:
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CP25Utils::decode(data, temp, 452U, 600U);
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break;
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case 3U:
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CP25Utils::decode(data, temp, 640U, 788U);
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break;
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case 4U:
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CP25Utils::decode(data, temp, 830U, 978U);
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break;
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case 5U:
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CP25Utils::decode(data, temp, 1020U, 1168U);
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break;
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case 6U:
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CP25Utils::decode(data, temp, 1208U, 1356U);
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break;
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case 7U:
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CP25Utils::decode(data, temp, 1398U, 1546U);
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break;
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case 8U:
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CP25Utils::decode(data, temp, 1578U, 1726U);
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break;
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default:
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return;
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}
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bool bit[144U];
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// De-interleave
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for (unsigned int i = 0U; i < 144U; i++) {
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unsigned int n = IMBE_INTERLEAVE[i];
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bit[i] = READ_BIT(temp, n);
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}
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// now ..
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// 12 voice bits 0
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// 11 golay bits 12
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//
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// 12 voice bits 23
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// 11 golay bits 35
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//
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// 12 voice bits 46
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// 11 golay bits 58
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//
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// 12 voice bits 69
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// 11 golay bits 81
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//
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// 11 voice bits 92
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// 4 hamming bits 103
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//
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// 11 voice bits 107
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// 4 hamming bits 118
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//
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// 11 voice bits 122
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// 4 hamming bits 133
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//
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// 7 voice bits 137
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// c0
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unsigned int c0data = 0U;
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for (unsigned int i = 0U; i < 12U; i++)
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c0data = (c0data << 1) | (bit[i] ? 0x01U : 0x00U);
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bool prn[114U];
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// Create the whitening vector and save it for future use
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unsigned int p = 16U * c0data;
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for (unsigned int i = 0U; i < 114U; i++) {
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p = (173U * p + 13849U) % 65536U;
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prn[i] = p >= 32768U;
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}
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// De-whiten some bits
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for (unsigned int i = 0U; i < 114U; i++)
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bit[i + 23U] ^= prn[i];
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unsigned int offset = 0U;
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for (unsigned int i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 0U]);
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for (unsigned int i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 23U]);
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for (unsigned int i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 46U]);
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for (unsigned int i = 0U; i < 12U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 69U]);
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for (unsigned int i = 0U; i < 11U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 92U]);
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for (unsigned int i = 0U; i < 11U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 107U]);
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for (unsigned int i = 0U; i < 11U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 122U]);
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for (unsigned int i = 0U; i < 7U; i++, offset++)
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WRITE_BIT(imbe, offset, bit[i + 137U]);
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}
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void CP25Audio::encode(unsigned char* data, const unsigned char* imbe, unsigned int n)
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{
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assert(data != NULL);
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assert(imbe != NULL);
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bool bTemp[144U];
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bool* bit = bTemp;
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// c0
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unsigned int c0 = 0U;
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for (unsigned int i = 0U; i < 12U; i++) {
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bool b = READ_BIT(imbe, i);
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c0 = (c0 << 1) | (b ? 0x01U : 0x00U);
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}
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unsigned int g2 = CGolay24128::encode23127(c0);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c1
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unsigned int c1 = 0U;
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for (unsigned int i = 12U; i < 24U; i++) {
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bool b = READ_BIT(imbe, i);
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c1 = (c1 << 1) | (b ? 0x01U : 0x00U);
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}
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g2 = CGolay24128::encode23127(c1);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c2
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unsigned int c2 = 0;
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for (unsigned int i = 24U; i < 36U; i++) {
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bool b = READ_BIT(imbe, i);
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c2 = (c2 << 1) | (b ? 0x01U : 0x00U);
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}
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g2 = CGolay24128::encode23127(c2);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c3
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unsigned int c3 = 0U;
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for (unsigned int i = 36U; i < 48U; i++) {
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bool b = READ_BIT(imbe, i);
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c3 = (c3 << 1) | (b ? 0x01U : 0x00U);
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}
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g2 = CGolay24128::encode23127(c3);
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for (int i = 23; i >= 0; i--) {
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bit[i] = (g2 & 0x01U) == 0x01U;
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g2 >>= 1;
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}
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bit += 23U;
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// c4
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for (unsigned int i = 0U; i < 11U; i++)
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bit[i] = READ_BIT(imbe, i + 48U);
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CHamming::encode15113_1(bit);
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bit += 15U;
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// c5
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for (unsigned int i = 0U; i < 11U; i++)
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bit[i] = READ_BIT(imbe, i + 59U);
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CHamming::encode15113_1(bit);
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bit += 15U;
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// c6
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for (unsigned int i = 0U; i < 11U; i++)
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bit[i] = READ_BIT(imbe, i + 70U);
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CHamming::encode15113_1(bit);
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bit += 15U;
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// c7
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for (unsigned int i = 0U; i < 7U; i++)
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bit[i] = READ_BIT(imbe, i + 81U);
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bool prn[114U];
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// Create the whitening vector and save it for future use
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unsigned int p = 16U * c0;
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for (unsigned int i = 0U; i < 114U; i++) {
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p = (173U * p + 13849U) % 65536U;
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prn[i] = p >= 32768U;
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}
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// Whiten some bits
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for (unsigned int i = 0U; i < 114U; i++)
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bTemp[i + 23U] ^= prn[i];
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unsigned char temp[18U];
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// Interleave
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for (unsigned int i = 0U; i < 144U; i++) {
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unsigned int n = IMBE_INTERLEAVE[i];
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WRITE_BIT(temp, n, bTemp[i]);
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}
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switch (n) {
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case 0U:
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CP25Utils::encode(temp, data, 114U, 262U);
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break;
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case 1U:
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CP25Utils::encode(temp, data, 262U, 410U);
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break;
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case 2U:
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CP25Utils::encode(temp, data, 452U, 600U);
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break;
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case 3U:
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CP25Utils::encode(temp, data, 640U, 788U);
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break;
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case 4U:
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CP25Utils::encode(temp, data, 830U, 978U);
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break;
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case 5U:
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CP25Utils::encode(temp, data, 1020U, 1168U);
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break;
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case 6U:
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CP25Utils::encode(temp, data, 1208U, 1356U);
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break;
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case 7U:
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CP25Utils::encode(temp, data, 1398U, 1546U);
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break;
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case 8U:
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CP25Utils::encode(temp, data, 1578U, 1726U);
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break;
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default:
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return;
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}
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}
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