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Refactor the Golay 24,12,8 code and its uses.

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This commit is contained in:
Jonathan Naylor 2021-04-07 19:56:28 +01:00
parent 8dc54ed21f
commit ffb4bdb042
6 changed files with 43 additions and 32 deletions
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26
AMBEFEC.cpp
View file

@ -793,22 +793,25 @@ unsigned int CAMBEFEC::regenerateIMBE(unsigned char* bytes) const
unsigned int CAMBEFEC::regenerateDStar(unsigned int& a, unsigned int& b) const unsigned int CAMBEFEC::regenerateDStar(unsigned int& a, unsigned int& b) const
{ {
bool valid;
unsigned int orig_a = a; unsigned int orig_a = a;
unsigned int orig_b = b; unsigned int orig_b = b;
unsigned int data = CGolay24128::decode24128(a, valid); unsigned int data;
bool valid1 = CGolay24128::decode24128(a, data);
a = CGolay24128::encode24128(data); if (!valid1)
return 10U;
// The PRNG // The PRNG
unsigned int p = PRNG_TABLE[data]; unsigned int p = PRNG_TABLE[data];
b ^= p; b ^= p;
unsigned int datb = CGolay24128::decode24128(b, valid); unsigned int datb;
bool valid2 = CGolay24128::decode24128(b, datb);
if (!valid2)
return 10U;
a = CGolay24128::encode24128(data);
b = CGolay24128::encode24128(datb); b = CGolay24128::encode24128(datb);
b ^= p; b ^= p;
@ -824,12 +827,17 @@ unsigned int CAMBEFEC::regenerateDStar(unsigned int& a, unsigned int& b) const
unsigned int CAMBEFEC::regenerateDMR(unsigned int& a, unsigned int& b, unsigned int& c) const unsigned int CAMBEFEC::regenerateDMR(unsigned int& a, unsigned int& b, unsigned int& c) const
{ {
bool valid;
unsigned int orig_a = a; unsigned int orig_a = a;
unsigned int orig_b = b; unsigned int orig_b = b;
unsigned int data = CGolay24128::decode24128(a, valid); unsigned int data;
bool valid = CGolay24128::decode24128(a, data);
if (!valid) {
a = 0xF00292U;
b = 0x0E0B20U;
c = 0x000000U;
return 10U; // An invalid A block gives an error count of 10
}
a = CGolay24128::encode24128(data); a = CGolay24128::encode24128(data);

20
Golay24128.cpp
View file

@ -1090,23 +1090,25 @@ unsigned int CGolay24128::decode23127(unsigned int code)
return code >> 11; return code >> 11;
} }
unsigned int CGolay24128::decode24128(unsigned int input, bool& valid) bool CGolay24128::decode24128(unsigned int in, unsigned int& out)
{ {
unsigned int syndrome = ::get_syndrome_23127(input >> 1); unsigned int syndrome = ::get_syndrome_23127(in >> 1);
unsigned int error_pattern = DECODING_TABLE_23127[syndrome] << 1; unsigned int error_pattern = DECODING_TABLE_23127[syndrome] << 1;
unsigned int output = input ^ error_pattern; out = in ^ error_pattern;
valid = (CUtils::countBits(syndrome) < 3U) || !(CUtils::countBits(output) & 1); bool valid = (CUtils::countBits(syndrome) < 3U) || !(CUtils::countBits(out) & 1);
return output >> 12; out >>= 12;
return valid;
} }
unsigned int CGolay24128::decode24128(unsigned char* bytes, bool& valid) bool CGolay24128::decode24128(unsigned char* in, unsigned int& out)
{ {
assert(bytes != NULL); assert(in != NULL);
unsigned int code = (bytes[0U] << 16) | (bytes[1U] << 8) | (bytes[2U] << 0); unsigned int code = (in[0U] << 16) | (in[1U] << 8) | (in[2U] << 0);
return decode24128(code, valid); return decode24128(code, out);
} }

5
Golay24128.h
View file

@ -25,8 +25,9 @@ public:
static unsigned int encode24128(unsigned int data); static unsigned int encode24128(unsigned int data);
static unsigned int decode23127(unsigned int code); static unsigned int decode23127(unsigned int code);
static unsigned int decode24128(unsigned int code, bool& valid);
static unsigned int decode24128(unsigned char* bytes, bool& valid); static bool decode24128(unsigned int in, unsigned int& out);
static bool decode24128(unsigned char* in, unsigned int& out);
}; };
#endif #endif

10
M17Control.cpp
View file

@ -212,11 +212,11 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
} }
if (m_rfState == RS_RF_LATE_ENTRY && data[0U] == TAG_DATA1) { if (m_rfState == RS_RF_LATE_ENTRY && data[0U] == TAG_DATA1) {
bool valid1, valid2, valid3, valid4; unsigned int lich1, lich2, lich3, lich4;
unsigned int lich1 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 0U, valid1); bool valid1 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 0U, lich1);
unsigned int lich2 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 3U, valid2); bool valid2 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 3U, lich2);
unsigned int lich3 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 6U, valid3); bool valid3 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 6U, lich3);
unsigned int lich4 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 9U, valid4); bool valid4 = CGolay24128::decode24128(data + 2U + M17_SYNC_LENGTH_BYTES + 9U, lich4);
if (!valid1 || !valid2 || !valid3 || !valid4) if (!valid1 || !valid2 || !valid3 || !valid4)
return false; return false;

2
Version.h
View file

@ -19,6 +19,6 @@
#if !defined(VERSION_H) #if !defined(VERSION_H)
#define VERSION_H #define VERSION_H
const char* VERSION = "20210329"; const char* VERSION = "20210407";
#endif #endif

12
YSFFICH.cpp
View file

@ -99,13 +99,13 @@ bool CYSFFICH::decode(const unsigned char* bytes)
unsigned char output[13U]; unsigned char output[13U];
viterbi.chainback(output, 96U); viterbi.chainback(output, 96U);
bool valid1, valid2, valid3, valid4; unsigned int b0, b1, b2, b3;
unsigned int b0 = CGolay24128::decode24128(output + 0U, valid1); bool valid0 = CGolay24128::decode24128(output + 0U, b0);
unsigned int b1 = CGolay24128::decode24128(output + 3U, valid2); bool valid1 = CGolay24128::decode24128(output + 3U, b1);
unsigned int b2 = CGolay24128::decode24128(output + 6U, valid3); bool valid2 = CGolay24128::decode24128(output + 6U, b2);
unsigned int b3 = CGolay24128::decode24128(output + 9U, valid4); bool valid3 = CGolay24128::decode24128(output + 9U, b3);
if (!valid1 || !valid2 || !valid3 || !valid4) if (!valid0 || !valid1 || !valid2 || !valid3)
return false; return false;
m_fich[0U] = (b0 >> 4) & 0xFFU; m_fich[0U] = (b0 >> 4) & 0xFFU;