Mercurial > gnulib
annotate tests/test-ffs.c @ 40057:b06060465f09
maint: Run 'make update-copyright'
| author | Paul Eggert <eggert@cs.ucla.edu> |
|---|---|
| date | Tue, 01 Jan 2019 00:25:11 +0100 |
| parents | 10eb9086bea0 |
| children |
| rev | line source |
|---|---|
| 15390 | 1 /* |
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40057
b06060465f09
maint: Run 'make update-copyright'
Paul Eggert <eggert@cs.ucla.edu>
parents:
19484
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changeset
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2 * Copyright (C) 2011-2019 Free Software Foundation, Inc. |
| 15390 | 3 * |
| 4 * This program is free software: you can redistribute it and/or modify | |
| 5 * it under the terms of the GNU General Public License as published by | |
| 6 * the Free Software Foundation; either version 3 of the License, or | |
| 7 * (at your option) any later version. | |
| 8 * | |
| 9 * This program is distributed in the hope that it will be useful, | |
| 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 12 * GNU General Public License for more details. | |
| 13 * | |
| 14 * You should have received a copy of the GNU General Public License | |
| 19190 | 15 * along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| 15390 | 16 |
| 17 /* Written by Eric Blake. */ | |
| 18 #include <config.h> | |
| 19 | |
| 20 #include <strings.h> | |
| 21 | |
| 22 #include "signature.h" | |
| 23 SIGNATURE_CHECK (ffs, int, (int)); | |
| 24 | |
| 25 #include <limits.h> | |
| 26 | |
| 27 #include "macros.h" | |
| 28 | |
| 15429 | 29 #define NBITS (sizeof (int) * CHAR_BIT) |
| 30 | |
| 15390 | 31 static int |
| 32 naive (int i) | |
| 33 { | |
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34 unsigned int j; |
| 15429 | 35 for (j = 0; j < NBITS; j++) |
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36 if (i & (1U << j)) |
| 15390 | 37 return j + 1; |
| 38 return 0; | |
| 39 } | |
| 40 | |
| 41 int | |
| 42 main (int argc, char *argv[]) | |
| 43 { | |
| 15429 | 44 int x; |
| 15390 | 45 int i; |
| 46 | |
| 15429 | 47 for (x = -128; x <= 128; x++) |
| 48 ASSERT (ffs (x) == naive (x)); | |
| 49 for (i = 0; i < NBITS; i++) | |
| 15390 | 50 { |
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51 ASSERT (ffs (1U << i) == naive (1U << i)); |
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52 ASSERT (ffs (1U << i) == i + 1); |
| 15429 | 53 ASSERT (ffs (-1U << i) == i + 1); |
| 54 } | |
| 55 for (i = 0; i < NBITS - 1; i++) | |
| 56 { | |
| 57 ASSERT (ffs (3U << i) == i + 1); | |
| 58 ASSERT (ffs (-3U << i) == i + 1); | |
| 59 } | |
| 60 for (i = 0; i < NBITS - 2; i++) | |
| 61 { | |
| 62 ASSERT (ffs (5U << i) == i + 1); | |
| 63 ASSERT (ffs (-5U << i) == i + 1); | |
| 64 ASSERT (ffs (7U << i) == i + 1); | |
| 65 ASSERT (ffs (-7U << i) == i + 1); | |
| 15390 | 66 } |
| 67 return 0; | |
| 68 } |