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added support for packed bits in the BCH decoder

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This commit is contained in:
Ahmet Inan 2018-09-21 19:48:09 +02:00
commit de2ef34eb3
2 changed files with 73 additions and 19 deletions
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46
tests/bch_decoder_test.cc
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@ -18,41 +18,49 @@ int main()
// NASA INTRO BCH(15, 5) T=3
typedef CODE::GaloisField<4, 0b10011, uint8_t> GF;
typedef CODE::BoseChaudhuriHocquenghemDecoder<6, 1, 5, GF> BCH;
const int L = (BCH::N + 7) / 8;
GF instance;
BCH decode;
uint8_t target[BCH::N] = { 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0 };
uint8_t code[BCH::N];
for (int i = 0; i < BCH::N; ++i)
uint8_t target[L] = { 0b11001000, 0b11110100 };
uint8_t code[L];
for (int i = 0; i < L; ++i)
code[i] = target[i];
std::uniform_int_distribution<uint8_t> distribution(0, BCH::N-1);
std::uniform_int_distribution<int> distribution(0, BCH::N-1);
auto noise = std::bind(distribution, generator);
for (int i = 0; i < 3; ++i)
code[noise()] ^= 1;
decode(reinterpret_cast<GF::ValueType *>(code));
for (int i = 0; i < BCH::N; ++i)
for (int i = 0; i < 3; ++i) {
int n = noise();
code[n / 8] ^= 128 >> (n % 8);
}
decode(code);
for (int i = 0; i < L; ++i)
assert(code[i] == target[i]);
}
if (1) {
// DVB-S2 FULL BCH(65535, 65343) T=12
typedef CODE::GaloisField<16, 0b10000000000101101, uint16_t> GF;
typedef CODE::BoseChaudhuriHocquenghemDecoder<24, 1, 65343, GF> BCH;
const int L = (BCH::N + 7) / 8;
GF *instance = new GF();
BCH *decode = new BCH();
uint16_t *target = new uint16_t[BCH::N];
uint8_t *target = new uint8_t[L];
for (int i = 0; i < L; ++i)
target[i] = 0;
for (int i = 0, s = 0; i < BCH::K; ++i, s=(s*(s*s*51767+71287)+35149)&0xffffff)
target[i] = (s^=s>>7)&1;
uint16_t parity[BCH::NP] = { 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0 };
target[i/8] |= ((s^=s>>7)&1) << (7-i%8);
bool parity[BCH::NP] = { 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0 };
for (int i = 0; i < BCH::NP; ++i)
target[BCH::K+i] = parity[i];
uint16_t *code = new uint16_t[BCH::N];
for (int i = 0; i < BCH::N; ++i)
target[(BCH::K+i)/8] |= parity[i] << (7-(BCH::K+i)%8);
uint8_t *code = new uint8_t[L];
for (int i = 0; i < L; ++i)
code[i] = target[i];
std::uniform_int_distribution<uint16_t> distribution(0, BCH::N-1);
std::uniform_int_distribution<int> distribution(0, BCH::N-1);
auto noise = std::bind(distribution, generator);
for (int i = 0; i < 12; ++i)
code[noise()] ^= 1;
(*decode)(reinterpret_cast<GF::ValueType *>(code));
for (int i = 0; i < BCH::N; ++i)
for (int i = 0; i < 12; ++i) {
int n = noise();
code[n / 8] ^= 128 >> (n % 8);
}
(*decode)(code);
for (int i = 0; i < L; ++i)
assert(code[i] == target[i]);
delete[] target;
delete[] code;