MMDVMHost-Private/P25Audio.cpp

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/*
* Copyright (C) 2016 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 "P25Audio.h"
#include "P25Utils.h"
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#include "Golay24128.h"
#include "Hamming.h"
#include <cstdio>
#include <cassert>
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const unsigned int IMBE_INTERLEAVE[] = {
0, 7, 12, 19, 24, 31, 36, 43, 48, 55, 60, 67, 72, 79, 84, 91, 96, 103, 108, 115, 120, 127, 132, 139,
1, 6, 13, 18, 25, 30, 37, 42, 49, 54, 61, 66, 73, 78, 85, 90, 97, 102, 109, 114, 121, 126, 133, 138,
2, 9, 14, 21, 26, 33, 38, 45, 50, 57, 62, 69, 74, 81, 86, 93, 98, 105, 110, 117, 122, 129, 134, 141,
3, 8, 15, 20, 27, 32, 39, 44, 51, 56, 63, 68, 75, 80, 87, 92, 99, 104, 111, 116, 123, 128, 135, 140,
4, 11, 16, 23, 28, 35, 40, 47, 52, 59, 64, 71, 76, 83, 88, 95, 100, 107, 112, 119, 124, 131, 136, 143,
5, 10, 17, 22, 29, 34, 41, 46, 53, 58, 65, 70, 77, 82, 89, 94, 101, 106, 113, 118, 125, 130, 137, 142};
const unsigned char BIT_MASK_TABLE[] = { 0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U };
#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])
#define READ_BIT(p,i) (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
CP25Audio::CP25Audio() :
m_fec()
{
}
CP25Audio::~CP25Audio()
{
}
unsigned int CP25Audio::process(unsigned char* data)
{
assert(data != NULL);
unsigned int errs = 0U;
unsigned char imbe[18U];
CP25Utils::decode(data, imbe, 114U, 262U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 114U, 262U);
CP25Utils::decode(data, imbe, 262U, 410U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 262U, 410U);
CP25Utils::decode(data, imbe, 452U, 600U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 452U, 600U);
CP25Utils::decode(data, imbe, 640U, 788U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 640U, 788U);
CP25Utils::decode(data, imbe, 830U, 978U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 830U, 978U);
CP25Utils::decode(data, imbe, 1020U, 1168U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 1020U, 1168U);
CP25Utils::decode(data, imbe, 1208U, 1356U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 1208U, 1356U);
CP25Utils::decode(data, imbe, 1398U, 1546U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 1398U, 1546U);
CP25Utils::decode(data, imbe, 1578U, 1726U);
errs += m_fec.regenerateIMBE(imbe);
CP25Utils::encode(imbe, data, 1578U, 1726U);
return errs;
}
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void CP25Audio::decode(const unsigned char* data, unsigned char* imbe, unsigned int n)
{
assert(data != NULL);
assert(imbe != NULL);
unsigned char temp[18U];
switch (n) {
case 0U:
CP25Utils::decode(data, temp, 114U, 262U);
break;
case 1U:
CP25Utils::decode(data, temp, 262U, 410U);
break;
case 2U:
CP25Utils::decode(data, temp, 452U, 600U);
break;
case 3U:
CP25Utils::decode(data, temp, 640U, 788U);
break;
case 4U:
CP25Utils::decode(data, temp, 830U, 978U);
break;
case 5U:
CP25Utils::decode(data, temp, 1020U, 1168U);
break;
case 6U:
CP25Utils::decode(data, temp, 1208U, 1356U);
break;
case 7U:
CP25Utils::decode(data, temp, 1398U, 1546U);
break;
case 8U:
CP25Utils::decode(data, temp, 1578U, 1726U);
break;
default:
return;
}
bool bit[144U];
// De-interleave
for (unsigned int i = 0U; i < 144U; i++) {
unsigned int n = IMBE_INTERLEAVE[i];
bit[i] = READ_BIT(temp, n);
}
// now ..
// 12 voice bits 0
// 11 golay bits 12
//
// 12 voice bits 23
// 11 golay bits 35
//
// 12 voice bits 46
// 11 golay bits 58
//
// 12 voice bits 69
// 11 golay bits 81
//
// 11 voice bits 92
// 4 hamming bits 103
//
// 11 voice bits 107
// 4 hamming bits 118
//
// 11 voice bits 122
// 4 hamming bits 133
//
// 7 voice bits 137
// c0
unsigned int c0data = 0U;
for (unsigned int i = 0U; i < 12U; i++)
c0data = (c0data << 1) | (bit[i] ? 0x01U : 0x00U);
bool prn[114U];
// Create the whitening vector and save it for future use
unsigned int p = 16U * c0data;
for (unsigned int i = 0U; i < 114U; i++) {
p = (173U * p + 13849U) % 65536U;
prn[i] = p >= 32768U;
}
// De-whiten some bits
for (unsigned int i = 0U; i < 114U; i++)
bit[i + 23U] ^= prn[i];
unsigned int offset = 0U;
for (unsigned int i = 0U; i < 12U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 0U]);
for (unsigned int i = 0U; i < 12U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 23U]);
for (unsigned int i = 0U; i < 12U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 46U]);
for (unsigned int i = 0U; i < 12U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 69U]);
for (unsigned int i = 0U; i < 11U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 92U]);
for (unsigned int i = 0U; i < 11U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 107U]);
for (unsigned int i = 0U; i < 11U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 122U]);
for (unsigned int i = 0U; i < 7U; i++, offset++)
WRITE_BIT(imbe, offset, bit[i + 137U]);
}
void CP25Audio::encode(unsigned char* data, const unsigned char* imbe, unsigned int n)
{
assert(data != NULL);
assert(imbe != NULL);
bool bTemp[144U];
bool* bit = bTemp;
// c0
unsigned int c0 = 0U;
for (unsigned int i = 0U; i < 12U; i++) {
bool b = READ_BIT(imbe, i);
c0 = (c0 << 1) | (b ? 0x01U : 0x00U);
}
unsigned int g2 = CGolay24128::encode23127(c0);
for (int i = 23; i >= 0; i--) {
bit[i] = (g2 & 0x01U) == 0x01U;
g2 >>= 1;
}
bit += 23U;
// c1
unsigned int c1 = 0U;
for (unsigned int i = 12U; i < 24U; i++) {
bool b = READ_BIT(imbe, i);
c1 = (c1 << 1) | (b ? 0x01U : 0x00U);
}
g2 = CGolay24128::encode23127(c1);
for (int i = 23; i >= 0; i--) {
bit[i] = (g2 & 0x01U) == 0x01U;
g2 >>= 1;
}
bit += 23U;
// c2
unsigned int c2 = 0;
for (unsigned int i = 24U; i < 36U; i++) {
bool b = READ_BIT(imbe, i);
c2 = (c2 << 1) | (b ? 0x01U : 0x00U);
}
g2 = CGolay24128::encode23127(c2);
for (int i = 23; i >= 0; i--) {
bit[i] = (g2 & 0x01U) == 0x01U;
g2 >>= 1;
}
bit += 23U;
// c3
unsigned int c3 = 0U;
for (unsigned int i = 36U; i < 48U; i++) {
bool b = READ_BIT(imbe, i);
c3 = (c3 << 1) | (b ? 0x01U : 0x00U);
}
g2 = CGolay24128::encode23127(c3);
for (int i = 23; i >= 0; i--) {
bit[i] = (g2 & 0x01U) == 0x01U;
g2 >>= 1;
}
bit += 23U;
// c4
for (unsigned int i = 0U; i < 11U; i++)
bit[i] = READ_BIT(imbe, i + 48U);
CHamming::encode15113_1(bit);
bit += 15U;
// c5
for (unsigned int i = 0U; i < 11U; i++)
bit[i] = READ_BIT(imbe, i + 59U);
CHamming::encode15113_1(bit);
bit += 15U;
// c6
for (unsigned int i = 0U; i < 11U; i++)
bit[i] = READ_BIT(imbe, i + 70U);
CHamming::encode15113_1(bit);
bit += 15U;
// c7
for (unsigned int i = 0U; i < 7U; i++)
bit[i] = READ_BIT(imbe, i + 81U);
bool prn[114U];
// Create the whitening vector and save it for future use
unsigned int p = 16U * c0;
for (unsigned int i = 0U; i < 114U; i++) {
p = (173U * p + 13849U) % 65536U;
prn[i] = p >= 32768U;
}
// Whiten some bits
for (unsigned int i = 0U; i < 114U; i++)
bTemp[i + 23U] ^= prn[i];
unsigned char temp[18U];
// Interleave
for (unsigned int i = 0U; i < 144U; i++) {
unsigned int n = IMBE_INTERLEAVE[i];
WRITE_BIT(temp, n, bTemp[i]);
}
switch (n) {
case 0U:
CP25Utils::encode(temp, data, 114U, 262U);
break;
case 1U:
CP25Utils::encode(temp, data, 262U, 410U);
break;
case 2U:
CP25Utils::encode(temp, data, 452U, 600U);
break;
case 3U:
CP25Utils::encode(temp, data, 640U, 788U);
break;
case 4U:
CP25Utils::encode(temp, data, 830U, 978U);
break;
case 5U:
CP25Utils::encode(temp, data, 1020U, 1168U);
break;
case 6U:
CP25Utils::encode(temp, data, 1208U, 1356U);
break;
case 7U:
CP25Utils::encode(temp, data, 1398U, 1546U);
break;
case 8U:
CP25Utils::encode(data, temp, 1578U, 1726U);
break;
default:
return;
}
}