// SPDX-License-Identifier: LGPL-2.1-or-later

/*

 * Reed-Solomon codecs, based on libfec

 *

 * Copyright (C) 2004 Phil Karn, KA9Q

 * libcryptsetup modifications

 *   Copyright (C) 2017-2025 Red Hat, Inc. All rights reserved.

 */

#ifndef _LIBFEC_RS_H

#define _LIBFEC_RS_H

/* Special reserved value encoding zero in index form. */

#define A0 (rs->nn)

#define RS_MIN(a, b) ((a) < (b) ? (a) : (b))

typedef unsigned char data_t;

/* Reed-Solomon codec control block */

struct rs {

  int mm;          /* Bits per symbol */

  int nn;          /* Symbols per block (= (1<<mm)-1) */

  data_t *alpha_to;/* log lookup table */

  data_t *index_of;/* Antilog lookup table */

  data_t *genpoly; /* Generator polynomial */

  int nroots;      /* Number of generator roots = number of parity symbols */

  int fcr;         /* First consecutive root, index form */

  int prim;        /* Primitive element, index form */

  int iprim;       /* prim-th root of 1, index form */

  int pad;         /* Padding bytes in shortened block */

};

static inline int modnn(struct rs *rs, int x)

{

  while (x >= rs->nn) {

    x -= rs->nn;

    x = (x >> rs->mm) + (x & rs->nn);

  }

  return x;

}

Unexecuted instantiation: verity_fec.c:modnn

Unexecuted instantiation: rs_encode_char.c:modnn

Unexecuted instantiation: rs_decode_char.c:modnn

struct rs *init_rs_char(int symsize, int gfpoly, int fcr, int prim, int nroots, int pad);

void free_rs_char(struct rs *rs);

/* General purpose RS codec, 8-bit symbols */

void encode_rs_char(struct rs *rs, data_t *data, data_t *parity);

int decode_rs_char(struct rs *rs, data_t *data);

#endif