mirror of
https://github.com/seiichiro0185/sailotp.git
synced 2024-05-05 03:54:00 +00:00
328 lines
9 KiB
C
328 lines
9 KiB
C
/*
|
|
* qrencode - QR Code encoder
|
|
*
|
|
* Reed solomon encoder. This code is taken from Phil Karn's libfec then
|
|
* editted and packed into a pair of .c and .h files.
|
|
*
|
|
* Copyright (C) 2002, 2003, 2004, 2006 Phil Karn, KA9Q
|
|
* (libfec is released under the GNU Lesser General Public License.)
|
|
*
|
|
* Copyright (C) 2006-2011 Kentaro Fukuchi <kentaro@fukuchi.org>
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#if HAVE_CONFIG_H
|
|
# include "config.h"
|
|
#endif
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#ifdef HAVE_LIBPTHREAD
|
|
# include <pthread.h>
|
|
#endif
|
|
|
|
#include "rscode.h"
|
|
|
|
/* Stuff specific to the 8-bit symbol version of the general purpose RS codecs
|
|
*
|
|
*/
|
|
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 */
|
|
int gfpoly;
|
|
struct _RS *next;
|
|
};
|
|
|
|
static RS *rslist = NULL;
|
|
#ifdef HAVE_LIBPTHREAD
|
|
static pthread_mutex_t rslist_mutex = PTHREAD_MUTEX_INITIALIZER;
|
|
#endif
|
|
|
|
static inline int modnn(RS *rs, int x){
|
|
while (x >= rs->nn) {
|
|
x -= rs->nn;
|
|
x = (x >> rs->mm) + (x & rs->nn);
|
|
}
|
|
return x;
|
|
}
|
|
|
|
|
|
#define MODNN(x) modnn(rs,x)
|
|
|
|
#define MM (rs->mm)
|
|
#define NN (rs->nn)
|
|
#define ALPHA_TO (rs->alpha_to)
|
|
#define INDEX_OF (rs->index_of)
|
|
#define GENPOLY (rs->genpoly)
|
|
#define NROOTS (rs->nroots)
|
|
#define FCR (rs->fcr)
|
|
#define PRIM (rs->prim)
|
|
#define IPRIM (rs->iprim)
|
|
#define PAD (rs->pad)
|
|
#define A0 (NN)
|
|
|
|
|
|
/* Initialize a Reed-Solomon codec
|
|
* symsize = symbol size, bits
|
|
* gfpoly = Field generator polynomial coefficients
|
|
* fcr = first root of RS code generator polynomial, index form
|
|
* prim = primitive element to generate polynomial roots
|
|
* nroots = RS code generator polynomial degree (number of roots)
|
|
* pad = padding bytes at front of shortened block
|
|
*/
|
|
static RS *init_rs_char(int symsize, int gfpoly, int fcr, int prim, int nroots, int pad)
|
|
{
|
|
RS *rs;
|
|
|
|
|
|
/* Common code for intializing a Reed-Solomon control block (char or int symbols)
|
|
* Copyright 2004 Phil Karn, KA9Q
|
|
* May be used under the terms of the GNU Lesser General Public License (LGPL)
|
|
*/
|
|
//#undef NULL
|
|
//#define NULL ((void *)0)
|
|
|
|
int i, j, sr,root,iprim;
|
|
|
|
rs = NULL;
|
|
/* Check parameter ranges */
|
|
if(symsize < 0 || symsize > (int)(8*sizeof(data_t))){
|
|
goto done;
|
|
}
|
|
|
|
if(fcr < 0 || fcr >= (1<<symsize))
|
|
goto done;
|
|
if(prim <= 0 || prim >= (1<<symsize))
|
|
goto done;
|
|
if(nroots < 0 || nroots >= (1<<symsize))
|
|
goto done; /* Can't have more roots than symbol values! */
|
|
if(pad < 0 || pad >= ((1<<symsize) -1 - nroots))
|
|
goto done; /* Too much padding */
|
|
|
|
rs = (RS *)calloc(1,sizeof(RS));
|
|
if(rs == NULL)
|
|
goto done;
|
|
|
|
rs->mm = symsize;
|
|
rs->nn = (1<<symsize)-1;
|
|
rs->pad = pad;
|
|
|
|
rs->alpha_to = (data_t *)malloc(sizeof(data_t)*(rs->nn+1));
|
|
if(rs->alpha_to == NULL){
|
|
free(rs);
|
|
rs = NULL;
|
|
goto done;
|
|
}
|
|
rs->index_of = (data_t *)malloc(sizeof(data_t)*(rs->nn+1));
|
|
if(rs->index_of == NULL){
|
|
free(rs->alpha_to);
|
|
free(rs);
|
|
rs = NULL;
|
|
goto done;
|
|
}
|
|
|
|
/* Generate Galois field lookup tables */
|
|
rs->index_of[0] = A0; /* log(zero) = -inf */
|
|
rs->alpha_to[A0] = 0; /* alpha**-inf = 0 */
|
|
sr = 1;
|
|
for(i=0;i<rs->nn;i++){
|
|
rs->index_of[sr] = i;
|
|
rs->alpha_to[i] = sr;
|
|
sr <<= 1;
|
|
if(sr & (1<<symsize))
|
|
sr ^= gfpoly;
|
|
sr &= rs->nn;
|
|
}
|
|
if(sr != 1){
|
|
/* field generator polynomial is not primitive! */
|
|
free(rs->alpha_to);
|
|
free(rs->index_of);
|
|
free(rs);
|
|
rs = NULL;
|
|
goto done;
|
|
}
|
|
|
|
/* Form RS code generator polynomial from its roots */
|
|
rs->genpoly = (data_t *)malloc(sizeof(data_t)*(nroots+1));
|
|
if(rs->genpoly == NULL){
|
|
free(rs->alpha_to);
|
|
free(rs->index_of);
|
|
free(rs);
|
|
rs = NULL;
|
|
goto done;
|
|
}
|
|
rs->fcr = fcr;
|
|
rs->prim = prim;
|
|
rs->nroots = nroots;
|
|
rs->gfpoly = gfpoly;
|
|
|
|
/* Find prim-th root of 1, used in decoding */
|
|
for(iprim=1;(iprim % prim) != 0;iprim += rs->nn)
|
|
;
|
|
rs->iprim = iprim / prim;
|
|
|
|
rs->genpoly[0] = 1;
|
|
for (i = 0,root=fcr*prim; i < nroots; i++,root += prim) {
|
|
rs->genpoly[i+1] = 1;
|
|
|
|
/* Multiply rs->genpoly[] by @**(root + x) */
|
|
for (j = i; j > 0; j--){
|
|
if (rs->genpoly[j] != 0)
|
|
rs->genpoly[j] = rs->genpoly[j-1] ^ rs->alpha_to[modnn(rs,rs->index_of[rs->genpoly[j]] + root)];
|
|
else
|
|
rs->genpoly[j] = rs->genpoly[j-1];
|
|
}
|
|
/* rs->genpoly[0] can never be zero */
|
|
rs->genpoly[0] = rs->alpha_to[modnn(rs,rs->index_of[rs->genpoly[0]] + root)];
|
|
}
|
|
/* convert rs->genpoly[] to index form for quicker encoding */
|
|
for (i = 0; i <= nroots; i++)
|
|
rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
|
|
done:;
|
|
|
|
return rs;
|
|
}
|
|
|
|
RS *init_rs(int symsize, int gfpoly, int fcr, int prim, int nroots, int pad)
|
|
{
|
|
RS *rs;
|
|
|
|
#ifdef HAVE_LIBPTHREAD
|
|
pthread_mutex_lock(&rslist_mutex);
|
|
#endif
|
|
for(rs = rslist; rs != NULL; rs = rs->next) {
|
|
if(rs->pad != pad) continue;
|
|
if(rs->nroots != nroots) continue;
|
|
if(rs->mm != symsize) continue;
|
|
if(rs->gfpoly != gfpoly) continue;
|
|
if(rs->fcr != fcr) continue;
|
|
if(rs->prim != prim) continue;
|
|
|
|
goto DONE;
|
|
}
|
|
|
|
rs = init_rs_char(symsize, gfpoly, fcr, prim, nroots, pad);
|
|
if(rs == NULL) goto DONE;
|
|
rs->next = rslist;
|
|
rslist = rs;
|
|
|
|
DONE:
|
|
#ifdef HAVE_LIBPTHREAD
|
|
pthread_mutex_unlock(&rslist_mutex);
|
|
#endif
|
|
return rs;
|
|
}
|
|
|
|
|
|
void free_rs_char(RS *rs)
|
|
{
|
|
free(rs->alpha_to);
|
|
free(rs->index_of);
|
|
free(rs->genpoly);
|
|
free(rs);
|
|
}
|
|
|
|
void free_rs_cache(void)
|
|
{
|
|
RS *rs, *next;
|
|
|
|
#ifdef HAVE_LIBPTHREAD
|
|
pthread_mutex_lock(&rslist_mutex);
|
|
#endif
|
|
rs = rslist;
|
|
while(rs != NULL) {
|
|
next = rs->next;
|
|
free_rs_char(rs);
|
|
rs = next;
|
|
}
|
|
rslist = NULL;
|
|
#ifdef HAVE_LIBPTHREAD
|
|
pthread_mutex_unlock(&rslist_mutex);
|
|
#endif
|
|
}
|
|
|
|
/* The guts of the Reed-Solomon encoder, meant to be #included
|
|
* into a function body with the following typedefs, macros and variables supplied
|
|
* according to the code parameters:
|
|
|
|
* data_t - a typedef for the data symbol
|
|
* data_t data[] - array of NN-NROOTS-PAD and type data_t to be encoded
|
|
* data_t parity[] - an array of NROOTS and type data_t to be written with parity symbols
|
|
* NROOTS - the number of roots in the RS code generator polynomial,
|
|
* which is the same as the number of parity symbols in a block.
|
|
Integer variable or literal.
|
|
*
|
|
* NN - the total number of symbols in a RS block. Integer variable or literal.
|
|
* PAD - the number of pad symbols in a block. Integer variable or literal.
|
|
* ALPHA_TO - The address of an array of NN elements to convert Galois field
|
|
* elements in index (log) form to polynomial form. Read only.
|
|
* INDEX_OF - The address of an array of NN elements to convert Galois field
|
|
* elements in polynomial form to index (log) form. Read only.
|
|
* MODNN - a function to reduce its argument modulo NN. May be inline or a macro.
|
|
* GENPOLY - an array of NROOTS+1 elements containing the generator polynomial in index form
|
|
|
|
* The memset() and memmove() functions are used. The appropriate header
|
|
* file declaring these functions (usually <string.h>) must be included by the calling
|
|
* program.
|
|
|
|
* Copyright 2004, Phil Karn, KA9Q
|
|
* May be used under the terms of the GNU Lesser General Public License (LGPL)
|
|
*/
|
|
|
|
#undef A0
|
|
#define A0 (NN) /* Special reserved value encoding zero in index form */
|
|
|
|
void encode_rs_char(RS *rs, const data_t *data, data_t *parity)
|
|
{
|
|
int i, j;
|
|
data_t feedback;
|
|
|
|
memset(parity,0,NROOTS*sizeof(data_t));
|
|
|
|
for(i=0;i<NN-NROOTS-PAD;i++){
|
|
feedback = INDEX_OF[data[i] ^ parity[0]];
|
|
if(feedback != A0){ /* feedback term is non-zero */
|
|
#ifdef UNNORMALIZED
|
|
/* This line is unnecessary when GENPOLY[NROOTS] is unity, as it must
|
|
* always be for the polynomials constructed by init_rs()
|
|
*/
|
|
feedback = MODNN(NN - GENPOLY[NROOTS] + feedback);
|
|
#endif
|
|
for(j=1;j<NROOTS;j++)
|
|
parity[j] ^= ALPHA_TO[MODNN(feedback + GENPOLY[NROOTS-j])];
|
|
}
|
|
/* Shift */
|
|
memmove(&parity[0],&parity[1],sizeof(data_t)*(NROOTS-1));
|
|
if(feedback != A0)
|
|
parity[NROOTS-1] = ALPHA_TO[MODNN(feedback + GENPOLY[0])];
|
|
else
|
|
parity[NROOTS-1] = 0;
|
|
}
|
|
}
|