p25p1_check_hdu.cpp

#include "p25p1_check_hdu.h"
#include "ReedSolomon.hpp"
#include "Golay24.hpp"

// Uncomment for very verbose trace messages
//#define CHECK_HDU_DEBUG

// The following methods are just a C bridge for the C++ implementations of the Golay and ReedSolomon
// algorithms.

static DSDGolay24 golay24;

static DSDReedSolomon_36_20_17 reed_solomon_36_20_17;

int check_and_fix_golay_24_6(char* hex, char* parity, int* fixed_errors)
{
#ifdef CHECK_HDU_DEBUG
    printf("[");
    for(unsigned int i=0; i<6; i++) {
        printf("%c", (hex[i] != 0)? 'X': ' ');
    }
    printf("]  [");
    for(unsigned int i=12; i<24; i++) {
        printf("%c", (parity[i-12] != 0)? 'X': ' ');
    }
    printf("]");
#endif

    int irrecoverable_errors = golay24.decode_6(hex, parity, fixed_errors);

#ifdef CHECK_HDU_DEBUG
    printf(" -> [");
    for(unsigned int i=0; i<6; i++) {
        printf("%c", (hex[i] != 0)? 'X': ' ');
    }
    printf("]");
    if (irrecoverable_errors) {
        printf("  Errors: >4");
    } else {
        printf("  Errors: %i", *fixed_errors);
    }
    printf("\n");
#endif

    return irrecoverable_errors;
}

int check_and_fix_golay_24_12(char* dodeca, char* parity, int* fixed_errors)
{
#ifdef CHECK_HDU_DEBUG
    printf("[");
    for(unsigned int i=0; i<12; i++) {
        printf("%c", (dodeca[i] != 0)? 'X': ' ');
    }
    printf("]  [");
    for(unsigned int i=12; i<24; i++) {
        printf("%c", (parity[i-12] != 0)? 'X': ' ');
    }
    printf("]");
#endif

    int irrecoverable_errors = golay24.decode_12(dodeca, parity, fixed_errors);

#ifdef CHECK_HDU_DEBUG
    printf(" -> [");
    for(unsigned int i=0; i<12; i++) {
        printf("%c", (dodeca[i] != 0)? 'X': ' ');
    }
    printf("]");
    if (irrecoverable_errors) {
        printf("  Errors: >4");
    } else {
        printf("  Errors: %i", *fixed_errors);
    }
    printf("\n");
#endif

    return irrecoverable_errors;
}

void encode_golay_24_6(char* hex, char* out_parity)
{
    golay24.encode_6(hex, out_parity);
}

void encode_golay_24_12(char* dodeca, char* out_parity)
{
    golay24.encode_12(dodeca, out_parity);
}


int check_and_fix_redsolomon_36_20_17(char* data, char* parity)
{
#ifdef CHECK_HDU_DEBUG
    char original[20][6];
    for (int i = 0; i < 20; i++) {
        for (int j = 0; j < 6; j++) {
            original[i][j] = data[i*6+j];
        }
    }
#endif

    int irrecoverable_errors = reed_solomon_36_20_17.decode(data, parity);

#ifdef CHECK_HDU_DEBUG
    printf("Results for Reed-Solomon code (36,20,17)\n\n");
    if (irrecoverable_errors == 0) {
        printf("  i  original fixed\n");
        for (int i = 0; i < 20; i++) {
            printf("%3d  [", i);
            for (int j = 0; j < 6; j++) {
                printf("%c", (original[i][j] == 1)? 'X' : ' ');
            }
            printf("] [");
            for (int j = 0; j < 6; j++) {
                printf("%c", (data[i*6+j] == 1)? 'X' : ' ');
            }
            printf("]\n");
        }
    } else {
        printf("Irrecoverable errors found\n");
        printf("  i  original fixed\n");
        for (int i = 0; i < 20; i++) {
            printf("%3d  [", i);
            for (int j = 0; j < 6; j++) {
                printf("%c", (original[i][j] == 1)? 'X' : ' ');
            }
            printf("]\n");
        }
    }
    printf("\n");
#endif

    return irrecoverable_errors;
}

void encode_reedsolomon_36_20_17(char* hex_data, char* fixed_parity)
{
    reed_solomon_36_20_17.encode(hex_data, fixed_parity);
}