HCoop / hcoop / debian / openafs.git / blame
| Commit | Line | Data |
|---|---|---|
| 805e021f CE |
1 | /* |
| 2 | * Copyright (C) 2014 by the Massachusetts Institute of Technology. | |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * Redistribution and use in source and binary forms, with or without | |
| 6 | * modification, are permitted provided that the following conditions | |
| 7 | * are met: | |
| 8 | * | |
| 9 | * * Redistributions of source code must retain the above copyright | |
| 10 | * notice, this list of conditions and the following disclaimer. | |
| 11 | * | |
| 12 | * * Redistributions in binary form must reproduce the above copyright | |
| 13 | * notice, this list of conditions and the following disclaimer in | |
| 14 | * the documentation and/or other materials provided with the | |
| 15 | * distribution. | |
| 16 | * | |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 18 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 19 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| 20 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| 21 | * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, | |
| 22 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
| 23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR | |
| 24 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
| 26 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 27 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
| 28 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 29 | */ | |
| 30 | ||
| 31 | /* | |
| 32 | * This contains portable implementations of the BSD ffs() suite of functions, | |
| 33 | * which locate the first or last bit set in a bit string. | |
| 34 | */ | |
| 35 | ||
| 36 | #ifndef OPENAFS_OPR_FFS_H | |
| 37 | #define OPENAFS_OPR_FFS_H | |
| 38 | ||
| 39 | static_inline int | |
| 40 | opr_ffs(int value) | |
| 41 | { | |
| 42 | afs_int32 i; | |
| 43 | afs_uint32 tmp = value; | |
| 44 | ||
| 45 | if (tmp == 0) | |
| 46 | return 0; | |
| 47 | /* This loop must terminate because tmp is nonzero and thus has at least | |
| 48 | * one bit set. */ | |
| 49 | for (i = 1;; ++i) { | |
| 50 | if (tmp & 1u) | |
| 51 | return i; | |
| 52 | else | |
| 53 | tmp >>= 1; | |
| 54 | } | |
| 55 | /* NOTREACHED */ | |
| 56 | } | |
| 57 | ||
| 58 | static_inline int | |
| 59 | opr_ffsll(long long value) | |
| 60 | { | |
| 61 | afs_int32 i; | |
| 62 | afs_uint64 tmp = value; | |
| 63 | ||
| 64 | if (tmp == 0) | |
| 65 | return 0; | |
| 66 | /* This loop must terminate because tmp is nonzero and thus has at least | |
| 67 | * one bit set. */ | |
| 68 | for (i = 1;; ++i) { | |
| 69 | if (tmp & 1ull) | |
| 70 | return i; | |
| 71 | else | |
| 72 | tmp >>= 1; | |
| 73 | } | |
| 74 | /* NOTREACHED */ | |
| 75 | } | |
| 76 | ||
| 77 | static_inline int | |
| 78 | opr_fls(int value) | |
| 79 | { | |
| 80 | afs_int32 i; | |
| 81 | /* tmp must be unsigned to avoid undefined behavior. */ | |
| 82 | afs_uint32 tmp = value; | |
| 83 | ||
| 84 | if (tmp == 0) | |
| 85 | return 0; | |
| 86 | /* This loop must terminate because tmp is nonzero and thus has at least | |
| 87 | * one bit set. */ | |
| 88 | for (i = 32;; --i) { | |
| 89 | if (tmp & 0x80000000u) | |
| 90 | return i; | |
| 91 | else | |
| 92 | tmp <<= 1; | |
| 93 | } | |
| 94 | /* NOTREACHED */ | |
| 95 | } | |
| 96 | ||
| 97 | static_inline int | |
| 98 | opr_flsll(long long value) | |
| 99 | { | |
| 100 | afs_int32 i; | |
| 101 | /* tmp must be unsigned to avoid undefined behavior. */ | |
| 102 | afs_uint64 tmp = value; | |
| 103 | ||
| 104 | if (tmp == 0) | |
| 105 | return 0; | |
| 106 | /* This loop must terminate because tmp is nonzero and thus has at least | |
| 107 | * one bit set. */ | |
| 108 | for (i = 64;; --i) { | |
| 109 | if (tmp & 0x8000000000000000ull) | |
| 110 | return i; | |
| 111 | else | |
| 112 | tmp <<= 1; | |
| 113 | } | |
| 114 | /* NOTREACHED */ | |
| 115 | } | |
| 116 | ||
| 117 | #endif /* OPENAFS_OPR_FFS_H */ |