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1 | /* bmpbit.c | |
2 | * Greg Cook, 27/Jun/2016 | |
3 | */ | |
4 | ||
5 | /* CRC RevEng: arbitrary-precision CRC calculator and algorithm finder | |
6 | * Copyright (C) 2010, 2011, 2012, 2013, 2014, 2015, 2016 Gregory Cook | |
7 | * | |
8 | * This file is part of CRC RevEng. | |
9 | * | |
10 | * CRC RevEng is free software: you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation, either version 3 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * CRC RevEng is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with CRC RevEng. If not, see <https://www.gnu.org/licenses/>. | |
22 | */ | |
23 | ||
24 | #ifdef BMPTST | |
25 | # include <stdio.h> | |
26 | # include <stdlib.h> | |
27 | #else | |
28 | # define FILE void | |
29 | #endif | |
30 | #include "reveng.h" | |
31 | ||
32 | #if (defined BMPTST) || (BMP_BIT < 32) | |
33 | /* Size in bits of a bmp_t. Not necessarily a power of two. */ | |
34 | int bmpbit; | |
35 | ||
36 | /* The highest power of two that is strictly less than BMP_BIT. | |
37 | * Initialises the index of a binary search for set bits in a bmp_t. | |
38 | * (Computed correctly for BMP_BIT >= 2) | |
39 | */ | |
40 | int bmpsub; | |
41 | ||
42 | void | |
43 | setbmp(void) { | |
44 | /* Initialise BMP_BIT and BMP_SUB for the local architecture. */ | |
45 | bmp_t bmpmax = ~(bmp_t) 0; | |
46 | ||
47 | bmpbit = 0; bmpsub = 1; | |
48 | ||
49 | while(bmpmax) { | |
50 | bmpmax <<= 1; | |
51 | ++bmpbit; | |
52 | } | |
53 | ||
54 | while((bmpsub | (bmpsub - 1)) < bmpbit - 1) | |
55 | bmpsub <<= 1; | |
56 | } | |
57 | #endif | |
58 | ||
59 | #ifdef BMPTST | |
60 | int | |
61 | main(int argc, char *argv[]) { | |
62 | /* check the compile-time bitmap width is correct, otherwise | |
63 | * searches run forever. */ | |
64 | # if BMP_BIT > 0 | |
65 | setbmp(); | |
66 | if(BMP_BIT != bmpbit || BMP_SUB != bmpsub) { | |
67 | fprintf(stderr,"reveng: configuration fault. Update " | |
68 | "config.h with these definitions and " | |
69 | "recompile:\n" | |
70 | "\t#define BMP_BIT %d\n" | |
71 | "\t#define BMP_SUB %d\n", | |
72 | bmpbit, bmpsub); | |
73 | exit(EXIT_FAILURE); | |
74 | } | |
75 | # endif /* BMP_BIT > 0 */ | |
76 | /* check the bitmap constant macro */ | |
77 | if(~(bmp_t) 0 != ~BMP_C(0)) { | |
78 | fprintf(stderr, "reveng: configuration fault. Edit " | |
79 | "the definition of BMP_C() in config.h to " | |
80 | "match BMP_T and recompile.\n"); | |
81 | exit(EXIT_FAILURE); | |
82 | } | |
83 | exit(EXIT_SUCCESS); | |
84 | } | |
85 | ||
86 | #endif /* BMPTST */ |