projects / thirdparty / strongswan.git / blame
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| 8f6c1327 TB |
1 | /* |
| 2 | * Copyright (C) 2011 Tobias Brunner | |
| 3 | * Hochschule fuer Technik Rapperswil | |
| 4 | * | |
| 5 | * This program is free software; you can redistribute it and/or modify it | |
| 6 | * under the terms of the GNU General Public License as published by the | |
| 7 | * Free Software Foundation; either version 2 of the License, or (at your | |
| 8 | * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>. | |
| 9 | * | |
| 10 | * This program is distributed in the hope that it will be useful, but | |
| 11 | * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
| 12 | * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 13 | * for more details. | |
| 14 | */ | |
| 15 | ||
| 16 | /** | |
| 17 | * @defgroup semaphore semaphore | |
| 18 | * @{ @ingroup threading | |
| 19 | */ | |
| 20 | ||
| 21 | #ifndef THREADING_SEMAPHORE_H_ | |
| 22 | #define THREADING_SEMAPHORE_H_ | |
| 23 | ||
| f65779dd | 24 | #include <utils/utils.h> |
| b0ccd14f | 25 | |
| 8f6c1327 TB |
26 | typedef struct semaphore_t semaphore_t; |
| 27 | ||
| 28 | /** | |
| 29 | * A semaphore is basically an integer whose value is never allowed to be | |
| 30 | * lower than 0. Two operations can be performed on it: increment the | |
| 31 | * value by one, and decrement the value by one. If the value is currently | |
| 2db6d5b8 | 32 | * zero, then the decrement operation will block until the value becomes |
| 8f6c1327 TB |
33 | * greater than zero. |
| 34 | */ | |
| 35 | struct semaphore_t { | |
| 36 | ||
| 37 | /** | |
| 38 | * Decrease the value by one, if it is greater than zero. Otherwise the | |
| 39 | * current thread is blocked and it waits until the value increases. | |
| 40 | */ | |
| 41 | void (*wait)(semaphore_t *this); | |
| 42 | ||
| 43 | /** | |
| 44 | * Decrease the value by one, if it is greater than zero. Otherwise the | |
| 45 | * current thread is blocked and it waits until the value increases, or the | |
| 46 | * call times out. | |
| 47 | * | |
| 48 | * @param timeout timeout im ms | |
| 49 | * @return TRUE if timed out, FALSE otherwise | |
| 50 | */ | |
| 51 | bool (*timed_wait)(semaphore_t *this, u_int timeout); | |
| 52 | ||
| 53 | /** | |
| 54 | * Decrease the value by one, if it is greater than zero. Otherwise the | |
| 55 | * current thread is blocked and it waits until the value increases, or the | |
| 56 | * call times out. | |
| 57 | * | |
| 58 | * The passed timeval should be calculated based on the time_monotonic() | |
| 59 | * function. | |
| 60 | * | |
| 61 | * @param tv absolute time until timeout | |
| 62 | * @return TRUE if timed out, FALSE otherwise | |
| 63 | */ | |
| 64 | bool (*timed_wait_abs)(semaphore_t *this, timeval_t tv); | |
| 65 | ||
| 66 | /** | |
| 67 | * Increase the value by one. If the value becomes greater than zero, then | |
| 68 | * another thread waiting will be woken up. | |
| 69 | */ | |
| 70 | void (*post)(semaphore_t *this); | |
| 71 | ||
| 72 | /** | |
| 73 | * Destroy a semaphore and free its resources. | |
| 74 | */ | |
| 75 | void (*destroy)(semaphore_t *this); | |
| 76 | }; | |
| 77 | ||
| 78 | /** | |
| 79 | * Create a semaphore instance. | |
| 80 | * | |
| 81 | * @param value initial value (typically 0) | |
| 82 | * @return semaphore instance | |
| 83 | */ | |
| 84 | semaphore_t *semaphore_create(u_int value); | |
| 85 | ||
| 86 | #endif /** THREADING_SEMAPHORE_H_ @} */ |