kopia lustrzana https://github.com/projecthorus/radiosonde_auto_rx
98 wiersze
2.8 KiB
C
98 wiersze
2.8 KiB
C
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/*
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* BCH / Reed-Solomon
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* encoder()
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* decoder() (Euklid. Alg.)
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*
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*
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* author: zilog80
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*
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*
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*/
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#ifdef INCLUDESTATIC
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#define INCSTAT static
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#else
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typedef unsigned char ui8_t;
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typedef unsigned int ui32_t;
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#define INCSTAT
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#endif
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#define MAX_DEG 254 // max N-1
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typedef struct {
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ui32_t f;
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ui32_t ord;
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ui8_t alpha;
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ui8_t exp_a[256];
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ui8_t log_a[256];
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} GF_t;
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typedef struct {
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ui8_t N;
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ui8_t t;
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ui8_t R; // RS: R=2t, BCH: R<=mt
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ui8_t K; // K=N-R
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ui8_t b;
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ui8_t p; ui8_t ip; // p*ip = 1 mod N
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ui8_t g[MAX_DEG+1]; // ohne g[] eventuell als init_return
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GF_t GF;
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} RS_t;
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static GF_t GF256RS = { .f = 0x11D, // RS-GF(2^8): X^8 + X^4 + X^3 + X^2 + 1 : 0x11D
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.ord = 256, // 2^8
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.alpha = 0x02, // generator: alpha = X
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.exp_a = {0},
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.log_a = {0} };
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static GF_t GF256RSccsds = { .f = 0x187, // RS-GF(2^8): X^8 + X^7 + X^2 + X + 1 : 0x187
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.ord = 256, // 2^8
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.alpha = 0x02, // generator: alpha = X
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.exp_a = {0},
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.log_a = {0} };
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static GF_t GF64BCH = { .f = 0x43, // BCH-GF(2^6): X^6 + X + 1 : 0x43
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.ord = 64, // 2^6
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.alpha = 0x02, // generator: alpha = X
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.exp_a = {0},
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.log_a = {0} };
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static GF_t GF16RS = { .f = 0x13, // RS-GF(2^4): X^4 + X + 1 : 0x13
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.ord = 16, // 2^4
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.alpha = 0x02, // generator: alpha = X
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.exp_a = {0},
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.log_a = {0} };
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static GF_t GF256AES = { .f = 0x11B, // AES-GF(2^8): X^8 + X^4 + X^3 + X + 1 : 0x11B
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.ord = 256, // 2^8
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.alpha = 0x03, // generator: alpha = X+1
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.exp_a = {0},
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.log_a = {0} };
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static RS_t RS256 = { 255, 12, 24, 231, 0, 1, 1, {0}, {0} };
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static RS_t RS256ccsds = { 255, 16, 32, 223, 112, 11, 116, {0}, {0} };
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static RS_t BCH64 = { 63, 2, 12, 51, 1, 1, 1, {0}, {0} };
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// static RS_t RS16_0 = { 15, 3, 6, 9, 0, 1, 1, {0}, {0} };
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static RS_t RS16ccsds = { 15, 2, 4, 11, 6, 1, 1, {0}, {0} };
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#ifndef INCLUDESTATIC
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int rs_init_RS255(RS_t *RS);
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int rs_init_RS255ccsds(RS_t *RS);
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int rs_init_RS15ccsds(RS_t *RS);
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int rs_init_BCH64(RS_t *RS);
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int rs_encode(RS_t *RS, ui8_t cw[]);
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int rs_decode(RS_t *RS, ui8_t cw[], ui8_t *err_pos, ui8_t *err_val);
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int rs_decode_ErrEra(RS_t *RS, ui8_t cw[], int nera, ui8_t era_pos[], ui8_t *err_pos, ui8_t *err_val);
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int rs_decode_bch_gf2t2(RS_t *RS, ui8_t cw[], ui8_t *err_pos, ui8_t *err_val);
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#endif
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