Revert "Fix the DMR, YSFDN, and NXDN FEC."

This reverts commit 7867eb5.

Author: g4klx

AMBEFEC.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2010,2014,2016,2018 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2010,2014,2016 by Jonathan Naylor G4KLX
  *   Copyright (C) 2016 Mathias Weyland, HB9FRV
  *
  *   This program is free software; you can redistribute it and/or modify
@@ -21,6 +21,8 @@
 #include "Hamming.h"
 #include "AMBEFEC.h"
 
+#include "Log.h"
+
 #include <cstdio>
 #include <cassert>
 
@@ -444,9 +446,9 @@ const unsigned int PRNG_TABLE[] = {
 const unsigned int DMR_A_TABLE[] = { 0U,  4U,  8U, 12U, 16U, 20U, 24U, 28U, 32U, 36U, 40U, 44U,
 									48U, 52U, 56U, 60U, 64U, 68U,  1U,  5U,  9U, 13U, 17U, 21U};
 const unsigned int DMR_B_TABLE[] = {25U, 29U, 33U, 37U, 41U, 45U, 49U, 53U, 57U, 61U, 65U, 69U,
-									 2U,  6U, 10U, 14U, 18U, 22U, 26U, 30U, 34U, 38U, 42U};
-const unsigned int DMR_C_TABLE[] = {46U, 50U, 54U, 58U, 62U, 66U, 70U,  3U,  7U, 11U, 15U, 19U,
-									23U, 27U, 31U, 35U, 39U, 43U, 47U, 51U, 55U, 59U, 63U, 67U, 71U};
+									 2U,  6U, 10U, 14U, 18U, 22U, 26U, 30U, 34U, 38U, 42U, 46U};
+const unsigned int DMR_C_TABLE[] = {50U, 54U, 58U, 62U, 66U, 70U,  3U,  7U, 11U, 15U, 19U, 23U,
+									27U, 31U, 35U, 39U, 43U, 47U, 51U, 55U, 59U, 63U, 67U, 71U};
 
 const unsigned int DSTAR_A_TABLE[] = {0U,  6U, 12U, 18U, 24U, 30U, 36U, 42U, 48U, 54U, 60U, 66U,
 									  1U,  7U, 13U, 19U, 25U, 31U, 37U, 43U, 49U, 55U, 61U, 67U};
@@ -477,97 +479,86 @@ unsigned int CAMBEFEC::regenerateDMR(unsigned char* bytes) const
 	assert(bytes != NULL);
 
 	unsigned int a1 = 0U, a2 = 0U, a3 = 0U;
+	unsigned int b1 = 0U, b2 = 0U, b3 = 0U;
+	unsigned int c1 = 0U, c2 = 0U, c3 = 0U;
+
 	unsigned int MASK = 0x800000U;
-	for (unsigned int i = 0U; i < 24U; i++, MASK >>= 1) {
+	for (unsigned int i = 0U; i < 24U; i++) {
 		unsigned int a1Pos = DMR_A_TABLE[i];
+		unsigned int b1Pos = DMR_B_TABLE[i];
+		unsigned int c1Pos = DMR_C_TABLE[i];
+
 		unsigned int a2Pos = a1Pos + 72U;
 		if (a2Pos >= 108U)
 			a2Pos += 48U;
+		unsigned int b2Pos = b1Pos + 72U;
+		if (b2Pos >= 108U)
+			b2Pos += 48U;
+		unsigned int c2Pos = c1Pos + 72U;
+		if (c2Pos >= 108U)
+			c2Pos += 48U;
+
 		unsigned int a3Pos = a1Pos + 192U;
+		unsigned int b3Pos = b1Pos + 192U;
+		unsigned int c3Pos = c1Pos + 192U;
 
 		if (READ_BIT(bytes, a1Pos))
 			a1 |= MASK;
 		if (READ_BIT(bytes, a2Pos))
 			a2 |= MASK;
 		if (READ_BIT(bytes, a3Pos))
 			a3 |= MASK;
-	}
-
-	unsigned int b1 = 0U, b2 = 0U, b3 = 0U;
-	MASK = 0x400000U;
-	for (unsigned int i = 0U; i < 23U; i++, MASK >>= 1) {
-		unsigned int b1Pos = DMR_B_TABLE[i];
-		unsigned int b2Pos = b1Pos + 72U;
-		if (b2Pos >= 108U)
-			b2Pos += 48U;
-		unsigned int b3Pos = b1Pos + 192U;
-
 		if (READ_BIT(bytes, b1Pos))
 			b1 |= MASK;
 		if (READ_BIT(bytes, b2Pos))
 			b2 |= MASK;
 		if (READ_BIT(bytes, b3Pos))
 			b3 |= MASK;
-	}
-
-	unsigned int c1 = 0U, c2 = 0U, c3 = 0U;
-	MASK = 0x1000000U;
-	for (unsigned int i = 0U; i < 25U; i++, MASK >>= 1) {
-		unsigned int c1Pos = DMR_C_TABLE[i];
-		unsigned int c2Pos = c1Pos + 72U;
-		if (c2Pos >= 108U)
-			c2Pos += 48U;
-		unsigned int c3Pos = c1Pos + 192U;
-
 		if (READ_BIT(bytes, c1Pos))
 			c1 |= MASK;
 		if (READ_BIT(bytes, c2Pos))
 			c2 |= MASK;
 		if (READ_BIT(bytes, c3Pos))
 			c3 |= MASK;
+
+		MASK >>= 1;
 	}
 
-	unsigned int errors = regenerateDMR(a1, b1);
-	errors += regenerateDMR(a2, b2);
-	errors += regenerateDMR(a3, b3);
+	unsigned int errors = regenerate(a1, b1, c1, true);
+	errors += regenerate(a2, b2, c2, true);
+	errors += regenerate(a3, b3, c3, true);
 
 	MASK = 0x800000U;
-	for (unsigned int i = 0U; i < 24U; i++, MASK >>= 1) {
+	for (unsigned int i = 0U; i < 24U; i++) {
 		unsigned int a1Pos = DMR_A_TABLE[i];
+		unsigned int b1Pos = DMR_B_TABLE[i];
+		unsigned int c1Pos = DMR_C_TABLE[i];
+
 		unsigned int a2Pos = a1Pos + 72U;
 		if (a2Pos >= 108U)
 			a2Pos += 48U;
-		unsigned int a3Pos = a1Pos + 192U;
-
-		WRITE_BIT(bytes, a1Pos, a1 & MASK);
-		WRITE_BIT(bytes, a2Pos, a2 & MASK);
-		WRITE_BIT(bytes, a3Pos, a3 & MASK);
-	}
-
-	MASK = 0x400000U;
-	for (unsigned int i = 0U; i < 23U; i++, MASK >>= 1) {
-		unsigned int b1Pos = DMR_B_TABLE[i];
 		unsigned int b2Pos = b1Pos + 72U;
 		if (b2Pos >= 108U)
 			b2Pos += 48U;
-		unsigned int b3Pos = b1Pos + 192U;
-
-		WRITE_BIT(bytes, b1Pos, b1 & MASK);
-		WRITE_BIT(bytes, b2Pos, b2 & MASK);
-		WRITE_BIT(bytes, b3Pos, b3 & MASK);
-	}
-
-	MASK = 0x1000000U;
-	for (unsigned int i = 0U; i < 25U; i++, MASK >>= 1) {
-		unsigned int c1Pos = DMR_C_TABLE[i];
 		unsigned int c2Pos = c1Pos + 72U;
 		if (c2Pos >= 108U)
 			c2Pos += 48U;
+
+		unsigned int a3Pos = a1Pos + 192U;
+		unsigned int b3Pos = b1Pos + 192U;
 		unsigned int c3Pos = c1Pos + 192U;
 
+		WRITE_BIT(bytes, a1Pos, a1 & MASK);
+		WRITE_BIT(bytes, a2Pos, a2 & MASK);
+		WRITE_BIT(bytes, a3Pos, a3 & MASK);
+		WRITE_BIT(bytes, b1Pos, b1 & MASK);
+		WRITE_BIT(bytes, b2Pos, b2 & MASK);
+		WRITE_BIT(bytes, b3Pos, b3 & MASK);
 		WRITE_BIT(bytes, c1Pos, c1 & MASK);
 		WRITE_BIT(bytes, c2Pos, c2 & MASK);
 		WRITE_BIT(bytes, c3Pos, c3 & MASK);
+
+		MASK >>= 1;
 	}
 
 	return errors;
@@ -592,7 +583,7 @@ unsigned int CAMBEFEC::regenerateDStar(unsigned char* bytes) const
 		MASK >>= 1;
 	}
 
-	unsigned int errors = regenerateDStar(a, b);
+	unsigned int errors = regenerate(a, b, c, false);
 
 	MASK = 0x800000U;
 	for (unsigned int i = 0U; i < 24U; i++) {
@@ -610,47 +601,38 @@ unsigned int CAMBEFEC::regenerateYSFDN(unsigned char* bytes) const
 	assert(bytes != NULL);
 
 	unsigned int a = 0U;
+	unsigned int b = 0U;
+	unsigned int c = 0U;
+
 	unsigned int MASK = 0x800000U;
-	for (unsigned int i = 0U; i < 24U; i++, MASK >>= 1) {
+	for (unsigned int i = 0U; i < 24U; i++) {
 		unsigned int aPos = DMR_A_TABLE[i];
+		unsigned int bPos = DMR_B_TABLE[i];
+		unsigned int cPos = DMR_C_TABLE[i];
+
 		if (READ_BIT(bytes, aPos))
 			a |= MASK;
-	}
-
-	unsigned int b = 0U;
-	MASK = 0x400000U;
-	for (unsigned int i = 0U; i < 23U; i++, MASK >>= 1) {
-		unsigned int bPos = DMR_B_TABLE[i];
 		if (READ_BIT(bytes, bPos))
 			b |= MASK;
-	}
-
-	unsigned int c = 0U;
-	MASK = 0x1000000U;
-	for (unsigned int i = 0U; i < 25U; i++, MASK >>= 1) {
-		unsigned int cPos = DMR_C_TABLE[i];
 		if (READ_BIT(bytes, cPos))
 			c |= MASK;
+
+		MASK >>= 1;
 	}
 
-	unsigned int errors = regenerateDMR(a, b);
+	unsigned int errors = regenerate(a, b, c, true);
 
 	MASK = 0x800000U;
-	for (unsigned int i = 0U; i < 24U; i++, MASK >>= 1) {
+	for (unsigned int i = 0U; i < 24U; i++) {
 		unsigned int aPos = DMR_A_TABLE[i];
-		WRITE_BIT(bytes, aPos, a & MASK);
-	}
-
-	MASK = 0x400000U;
-	for (unsigned int i = 0U; i < 23U; i++, MASK >>= 1) {
 		unsigned int bPos = DMR_B_TABLE[i];
-		WRITE_BIT(bytes, bPos, b & MASK);
-	}
-
-	MASK = 0x1000000U;
-	for (unsigned int i = 0U; i < 25U; i++, MASK >>= 1) {
 		unsigned int cPos = DMR_C_TABLE[i];
+
+		WRITE_BIT(bytes, aPos, a & MASK);
+		WRITE_BIT(bytes, bPos, b & MASK);
 		WRITE_BIT(bytes, cPos, c & MASK);
+
+		MASK >>= 1;
 	}
 
 	return errors;
@@ -790,14 +772,17 @@ unsigned int CAMBEFEC::regenerateIMBE(unsigned char* bytes) const
 	return errors;
 }
 
-unsigned int CAMBEFEC::regenerateDStar(unsigned int& a, unsigned int& b) const
+unsigned int CAMBEFEC::regenerate(unsigned int& a, unsigned int& b, unsigned int& c, bool b23) const
 {
-	unsigned int orig_a = a;
-	unsigned int orig_b = b;
+	unsigned int old_a = a;
+	unsigned int old_b = b;
+
+	// For the b23 bypass
+	bool b24 = (b & 0x01U) == 0x01U;
 
 	unsigned int data = CGolay24128::decode24128(a);
 
-	a = CGolay24128::encode24128(data);
+	unsigned int new_a = CGolay24128::encode24128(data);
 
 	// The PRNG
 	unsigned int p = PRNG_TABLE[data];
@@ -806,60 +791,39 @@ unsigned int CAMBEFEC::regenerateDStar(unsigned int& a, unsigned int& b) const
 
 	unsigned int datb = CGolay24128::decode24128(b);
 
-	b = CGolay24128::encode24128(datb);
+	unsigned int new_b = CGolay24128::encode24128(datb);
 
-	b ^= p;
+	new_b ^= p;
+
+	if (b23) {
+		new_b &= 0xFFFFFEU;
+		new_b |= b24 ? 0x01U : 0x00U;
+	}
 
 	unsigned int errsA = 0U, errsB = 0U;
 
-	unsigned int v = a ^ orig_a;
+	unsigned int v = new_a ^ old_a;
 	while (v != 0U) {
 		v &= v - 1U;
 		errsA++;
 	}
 
-	v = b ^ orig_b;
+	v = new_b ^ old_b;
 	while (v != 0U) {
 		v &= v - 1U;
 		errsB++;
 	}
 
-	return errsA + errsB;
-}
-
-unsigned int CAMBEFEC::regenerateDMR(unsigned int& a, unsigned int& b) const
-{
-	unsigned int orig_a = a;
-	unsigned int orig_b = b;
-
-	unsigned int data = CGolay24128::decode24128(a);
-
-	a = CGolay24128::encode24128(data);
-
-	// The PRNG
-	unsigned int p = PRNG_TABLE[data] >> 1;
-
-	b ^= p;
-
-	unsigned int datb = CGolay24128::decode23127(b);
-
-	b = CGolay24128::encode23127(datb);
-
-	b ^= p;
-
-	unsigned int errsA = 0U, errsB = 0U;
-
-	unsigned int v = a ^ orig_a;
-	while (v != 0U) {
-		v &= v - 1U;
-		errsA++;
+	if (b23) {
+		if (errsA >= 4U || ((errsA + errsB) >= 6U && errsA >= 2U)) {
+			a = 0xF00292U;
+			b = 0x0E0B20U;
+			c = 0x000000U;
+		}
 	}
 
-	v = b ^ orig_b;
-	while (v != 0U) {
-		v &= v - 1U;
-		errsB++;
-	}
+	a = new_a;
+	b = new_b;
 
 	return errsA + errsB;
 }

AMBEFEC.h

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2010,2014,2016,2018 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2010,2014,2016 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
@@ -33,8 +33,7 @@ class CAMBEFEC {
 	unsigned int regenerateIMBE(unsigned char* bytes) const;
 
 private:
-	unsigned int regenerateDStar(unsigned int& a, unsigned int& b) const;
-	unsigned int regenerateDMR(unsigned int& a, unsigned int& b) const;
+	unsigned int regenerate(unsigned int& a, unsigned int& b, unsigned int& c, bool b23) const;
 };
 
 #endif