projects / urcu.git / blame
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1 | // SPDX-FileCopyrightText: 1996 Ulrich Drepper <drepper@cygnus.com> |
| 2 | // SPDX-FileCopyrightText: 2013 Pierre-Luc St-Charles <pierre-luc.st-charles@polymtl.ca> | |
| 3 | // | |
| 4 | // SPDX-License-Identifier: LGPL-2.1-or-later | |
| 5 | ||
| 094c8c59 MJ |
6 | #ifndef _COMPAT_RAND_H |
| 7 | #define _COMPAT_RAND_H | |
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8 | |
| 9 | /* | |
| e1c0b55c PLSC |
10 | * Userspace RCU library - rand/rand_r Compatibility Header |
| 11 | * | |
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12 | * Note: this file is only used to simplify the code required to |
| 13 | * use the 'rand_r(...)' system function across multiple platforms, | |
| 14 | * which might not always be referenced the same way. | |
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15 | */ |
| 16 | ||
| 3e4ae45a | 17 | #ifndef HAVE_RAND_R |
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18 | /* |
| 19 | * Reentrant random function from POSIX.1c. | |
| 20 | * Copyright (C) 1996, 1999 Free Software Foundation, Inc. | |
| 21 | * This file is part of the GNU C Library. | |
| 22 | * Contributed by Ulrich Drepper <drepper@cygnus.com <mailto:drepper@cygnus.com>>, 1996. | |
| 23 | */ | |
| 24 | static inline int rand_r(unsigned int *seed) | |
| 25 | { | |
| 26 | unsigned int next = *seed; | |
| 27 | int result; | |
| 28 | ||
| 29 | next *= 1103515245; | |
| 30 | next += 12345; | |
| 31 | result = (unsigned int) (next / 65536) % 2048; | |
| 32 | ||
| 33 | next *= 1103515245; | |
| 34 | next += 12345; | |
| 35 | result <<= 10; | |
| 36 | result ^= (unsigned int) (next / 65536) % 1024; | |
| 37 | ||
| 38 | next *= 1103515245; | |
| 39 | next += 12345; | |
| 40 | result <<= 10; | |
| 41 | result ^= (unsigned int) (next / 65536) % 1024; | |
| 42 | ||
| 43 | *seed = next; | |
| 44 | ||
| 45 | return result; | |
| 46 | } | |
| 3e4ae45a | 47 | #endif /* HAVE_RAND_R */ |
| e1c0b55c | 48 | |
| 094c8c59 | 49 | #endif /* _COMPAT_RAND_H */ |