RRG-Proxmark3/client/deps/reveng/bmpbit.c

95 lines
2.5 KiB
C

/* bmpbit.c
* Greg Cook, 23/Feb/2019
*/
/* CRC RevEng: arbitrary-precision CRC calculator and algorithm finder
* Copyright (C) 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018,
* 2019 Gregory Cook
*
* This file is part of CRC RevEng.
*
* CRC RevEng is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* CRC RevEng 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with CRC RevEng. If not, see <https://www.gnu.org/licenses/>.
*/
#ifdef BMPTST
# include <stdio.h>
# include <stdlib.h>
#else
# define FILE void
#endif
#include "reveng.h"
#ifdef BMPTST
# undef fprintf
# undef puts
# undef fputs
#endif
#if (defined BMPTST) || (BMP_BIT < 32)
/* Size in bits of a bmp_t. Not necessarily a power of two. */
int bmpbit;
/* The highest power of two that is strictly less than BMP_BIT.
* Initialises the index of a binary search for set bits in a bmp_t.
* (Computed correctly for BMP_BIT >= 2)
*/
int bmpsub;
void
setbmp(void) {
/* Initialise BMP_BIT and BMP_SUB for the local architecture. */
bmp_t bmpmax = ~(bmp_t) 0;
bmpbit = 0;
bmpsub = 1;
while (bmpmax) {
bmpmax <<= 1;
++bmpbit;
}
while ((bmpsub | (bmpsub - 1)) < bmpbit - 1)
bmpsub <<= 1;
}
#endif
#ifdef BMPTST
int
main(int argc, char *argv[]) {
/* check the compile-time bitmap width is correct, otherwise
* searches run forever. */
# if BMP_BIT > 0
setbmp();
if (BMP_BIT != bmpbit || BMP_SUB != bmpsub) {
fprintf(stderr, "reveng: configuration fault. Update "
"reveng/config.h with these definitions and "
"recompile:\n"
"\t#define BMP_BIT %d\n"
"\t#define BMP_SUB %d\n",
bmpbit, bmpsub);
exit(EXIT_FAILURE);
}
# endif /* BMP_BIT > 0 */
/* check the bitmap constant macro */
if (~(bmp_t) 0 != ~BMP_C(0)) {
fprintf(stderr, "reveng: configuration fault. Edit "
"the definition of BMP_C() in config.h to "
"match BMP_T and recompile.\n");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
#endif /* BMPTST */