Line data    Source code

       1              : /*
       2              :  * libpoporon - encode.c
       3              :  * 
       4              :  * Copyright (c) 2025 Go Kudo
       5              :  *
       6              :  * This library is licensed under the BSD 3-Clause License.
       7              :  * For license details, please refer to the LICENSE file.
       8              :  *
       9              :  * SPDX-FileCopyrightText: Go Kudo <zeriyoshi@gmail.com>
      10              :  * SPDX-License-Identifier: BSD-3-Clause
      11              :  */
      12              : 
      13              : #include "poporon_internal.h"
      14              : 
      15            7 : extern bool poporon_encode_u8(poporon_t *pprn, uint8_t *data, size_t size, uint8_t *parity)
      16              : {
      17              :     uint16_t i, j, fb;
      18              : 
      19            7 :     if (!pprn || !data || !parity) {
      20            3 :         return false;
      21              :     }
      22              : 
      23            4 :     pmemset(parity, 0, pprn->rs->num_roots * sizeof(uint8_t));
      24              : 
      25          260 :     for (i = 0; i < size; i++) {
      26          256 :         fb = pprn->rs->gf->exp2log[(((uint16_t)data[i]) & ((uint16_t)pprn->rs->gf->field_size)) ^ parity[0]];
      27              :         
      28          256 :         if (fb != pprn->rs->gf->field_size) {
      29         8192 :             for (j = 1; j < pprn->rs->num_roots; j++) {
      30         7936 :                 parity[j] ^= pprn->rs->gf->log2exp[gf_mod(pprn->rs->gf, fb + pprn->rs->generator_polynomial[pprn->rs->num_roots - j])];
      31              :             }
      32              :         }
      33              :         
      34          256 :         pmemmove(&parity[0], &parity[1], sizeof(uint8_t) * (pprn->rs->num_roots - 1));
      35              :         
      36          256 :         if (fb != pprn->rs->gf->field_size) {
      37          256 :             parity[pprn->rs->num_roots - 1] = pprn->rs->gf->log2exp[gf_mod(pprn->rs->gf, fb + pprn->rs->generator_polynomial[0])];
      38              :         } else {
      39            0 :             parity[pprn->rs->num_roots - 1] = 0;
      40              :         }
      41              :     }
      42              : 
      43            4 :     return true;
      44              : }