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Annotation of embedaddon/strongswan/src/libstrongswan/threading/windows/spinlock.c, revision 1.1

1.1     ! misho       1: /*
        !             2:  * Copyright (C) 2013 Martin Willi
        !             3:  * Copyright (C) 2013 revosec AG
        !             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: #include <library.h>
        !            17: #include <threading/spinlock.h>
        !            18: 
        !            19: typedef struct private_spinlock_t private_spinlock_t;
        !            20: 
        !            21: /**
        !            22:  * private data of spinlock
        !            23:  */
        !            24: struct private_spinlock_t {
        !            25: 
        !            26:        /**
        !            27:         * public functions
        !            28:         */
        !            29:        spinlock_t public;
        !            30: 
        !            31:        /**
        !            32:         * wrapped critical section
        !            33:         */
        !            34:        CRITICAL_SECTION cs;
        !            35: };
        !            36: 
        !            37: METHOD(spinlock_t, lock, void,
        !            38:        private_spinlock_t *this)
        !            39: {
        !            40:        EnterCriticalSection(&this->cs);
        !            41: }
        !            42: 
        !            43: METHOD(spinlock_t, unlock, void,
        !            44:        private_spinlock_t *this)
        !            45: {
        !            46:        LeaveCriticalSection(&this->cs);
        !            47: }
        !            48: 
        !            49: METHOD(spinlock_t, destroy, void,
        !            50:        private_spinlock_t *this)
        !            51: {
        !            52:        DeleteCriticalSection(&this->cs);
        !            53:        free(this);
        !            54: }
        !            55: 
        !            56: /*
        !            57:  * see header file
        !            58:  */
        !            59: spinlock_t *spinlock_create()
        !            60: {
        !            61:        private_spinlock_t *this;
        !            62: 
        !            63:        INIT(this,
        !            64:                .public = {
        !            65:                        .lock = _lock,
        !            66:                        .unlock = _unlock,
        !            67:                        .destroy = _destroy,
        !            68:                },
        !            69:        );
        !            70: 
        !            71:        /* Usually the wait time in a spinlock should be short, so we could have
        !            72:         * a high spincount. But having a large/INFINITE spincount does not scale
        !            73:         * that well where a spinlock is not the perfect choice for a lock. We
        !            74:         * choose the spincount quite arbitrary, so we go to wait if it is not
        !            75:         * much more expensive than spinning. */
        !            76:        InitializeCriticalSectionAndSpinCount(&this->cs, 256);
        !            77: 
        !            78:        return &this->public;
        !            79: }