Reed Solomon Error Correcting Code

Header file

#include "mln_rs.h"

Module

rs

Functions/Macros

mln_rs_encode

mln_rs_result_t *mln_rs_encode(uint8_t *data_vector, size_t len, size_t n, size_t k);

Description: Generate error correction codes. Parameter meaning:

• data_vector stores several packets. Since the packets must be of the same length, a one-dimensional pointer is directly passed in here to improve processing performance.
• len The length of each piece of data.
• How many pieces of data in n.
• How many segments of k error correction codes need to be generated.

The generated result will contain the original data in the error correction code, and the error correction code will be stored after the data.

Return value: return mln_rs_result_t structure pointer if successful, otherwise return NULL

mln_rs_decode

mln_rs_result_t *mln_rs_decode(uint8_t **data_vector, size_t len, size_t n, size_t k);

Description: Use error correction codes for error correction. Parameter meaning:

• data_vector An array of messages including error correction codes. Note: This is a two-dimensional array. Note 1: The order of the packets in the data area must be the same as when they were generated, and NULL is given to the missing packets, but the order cannot be disordered. Note 2: When the number of missing data is more than k, it cannot be repaired.
• len The length of each piece of data.
• n The total number of pieces of data in the original.
• k How many segments of the original error correction code were generated.

Return value: return mln_rs_result_t structure pointer if successful, otherwise return NULL

mln_rs_result_free

void mln_rs_result_free(mln_rs_result_t *result);

Description: Frees the result structure produced by the above function.

Return value: none

mln_rs_result_get_num

mln_rs_result_get_num(_presult)

Description: Get the number of processing results in _presult of class behavior mln_rs_result_t.

Return value: the number of processing results

mln_rs_result_get_data_by_index

mln_rs_result_get_data_by_index(_presult,index)

Description: Get the data subscripted index in _presult of class behavior mln_rs_result_t, index starts from 0.

Return value: result data memory address

Example

#include <stdio.h>
#include "mln_string.h"
#include "mln_rs.h"

int main(int argc, char *argv[])
{
    mln_rs_result_t *res, *dres;
    char origin[] = "AAAABBBBCCCCDDDD";
    uint8_t *err[6] = {0};
    mln_string_t tmp;

    res = mln_rs_encode((uint8_t *)origin, 4, 4, 2);
    if (res == NULL) {
        fprintf(stderr, "rs encode failed.\n");
        return -1;
    }

    err[0] = NULL;
    err[1] = NULL;
    err[2] = (uint8_t *)origin+8;
    err[3] = (uint8_t *)origin+12;
    err[4] = mln_rs_result_get_data_by_index(res, 4);
    err[5] = mln_rs_result_get_data_by_index(res, 5);

    dres = mln_rs_decode(err, 4, 4, 2);
    if (dres == NULL) {
        fprintf(stderr, "rs decode failed.\n");
        return -1;
    }

    mln_string_nset(&tmp, mln_rs_result_get_data_by_index(dres, 1), 4);
    write(STDOUT_FILENO, tmp.data, tmp.len);
    write(STDOUT_FILENO, "\n", 1);

    mln_rs_result_free(res);
    mln_rs_result_free(dres);
    return 0;
}