| /** @addtogroup MCD_MCDIMPL_DAEMON_SRV |
| * @{ |
| * @file |
| * |
| * Semaphore implementation (pthread wrapper). |
| * |
| * <!-- Copyright Giesecke & Devrient GmbH 2009 - 2012 --> |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| #include <time.h> |
| #include <limits.h> |
| #include "CSemaphore.h" |
| #include <stdio.h> |
| |
| //------------------------------------------------------------------------------ |
| CSemaphore::CSemaphore(int size) : m_waiters_count(0), m_count(size) |
| { |
| pthread_mutex_init(&m_mutex, NULL); |
| pthread_cond_init(&m_cond, NULL); |
| } |
| |
| |
| //------------------------------------------------------------------------------ |
| CSemaphore::~CSemaphore() |
| { |
| pthread_mutex_destroy(&m_mutex); |
| pthread_cond_destroy(&m_cond); |
| } |
| |
| |
| //------------------------------------------------------------------------------ |
| void CSemaphore::wait() |
| { |
| pthread_mutex_lock(&m_mutex); |
| m_waiters_count ++; |
| while ( m_count == 0 ) |
| pthread_cond_wait(&m_cond, &m_mutex); |
| m_waiters_count --; |
| m_count --; |
| pthread_mutex_unlock(&m_mutex); |
| } |
| |
| //------------------------------------------------------------------------------ |
| bool CSemaphore::wait(int sec) |
| { |
| int rc = 0; |
| struct timespec tm; |
| if (sec < 0) |
| sec = LONG_MAX; |
| clock_gettime(CLOCK_REALTIME, &tm); |
| tm.tv_sec += sec; |
| |
| pthread_mutex_lock(&m_mutex); |
| m_waiters_count ++; |
| if ( m_count == 0 ) { |
| rc = pthread_cond_timedwait(&m_cond, &m_mutex, &tm); |
| } |
| m_waiters_count --; |
| // Decrement only if waiting actually succeeded, otherwise we |
| // just timed out |
| if (!rc) |
| m_count --; |
| pthread_mutex_unlock(&m_mutex); |
| return (rc == 0); |
| } |
| |
| |
| //------------------------------------------------------------------------------ |
| bool CSemaphore::wouldWait() |
| { |
| bool ret = false; |
| pthread_mutex_lock(&m_mutex); |
| if ( m_count == 0 ) |
| ret = true; |
| pthread_mutex_unlock(&m_mutex); |
| return ret; |
| } |
| |
| |
| //------------------------------------------------------------------------------ |
| void CSemaphore::signal() |
| { |
| pthread_mutex_lock(&m_mutex); |
| if ( m_waiters_count > 0 ) |
| pthread_cond_signal(&m_cond); |
| m_count ++; |
| pthread_mutex_unlock(&m_mutex); |
| } |
| |
| /** @} */ |