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/*
* $Id: mrwlock.c,v 1.2 2005/11/20 17:43:54 bestorga-oss Exp $
*
* (C) Copyright IBM Corp. 2003
*
* THIS FILE IS PROVIDED UNDER THE TERMS OF THE ECLIPSE PUBLIC LICENSE
* ("AGREEMENT"). ANY USE, REPRODUCTION OR DISTRIBUTION OF THIS FILE
* CONSTITUTES RECIPIENTS ACCEPTANCE OF THE AGREEMENT.
*
* You can obtain a current copy of the Eclipse Public License from
* http://www.opensource.org/licenses/eclipse-1.0.php
*
* Author: Viktor Mihajlovski <mihajlov@de.ibm.cim>
* Contributors:
*
* Description: Multiple Reader/Single Writer Locks
*/
#include "mrwlock.h"
int
MReadLock(MRWLOCK * mrwl)
{
if (mrwl && pthread_mutex_lock(&mrwl->mrw_mutex) == 0) {
mrwl->mrw_rnum += 1;
return pthread_mutex_unlock(&mrwl->mrw_mutex);
} else {
return -1;
}
}
int
MReadUnlock(MRWLOCK * mrwl)
{
if (mrwl && pthread_mutex_lock(&mrwl->mrw_mutex) == 0) {
mrwl->mrw_rnum -= 1;
if (mrwl->mrw_rnum == 0)
pthread_cond_broadcast(&mrwl->mrw_cond);
return pthread_mutex_unlock(&mrwl->mrw_mutex);
} else {
return -1;
}
}
int
MWriteLock(MRWLOCK * mrwl)
{
if (mrwl && pthread_mutex_lock(&mrwl->mrw_mutex) == 0) {
while (mrwl->mrw_rnum)
pthread_cond_wait(&mrwl->mrw_cond, &mrwl->mrw_mutex);
return 0;
} else {
return -1;
}
}
int
MWriteUnlock(MRWLOCK * mrwl)
{
if (mrwl && pthread_mutex_unlock(&mrwl->mrw_mutex) == 0) {
return 0;
} else {
return -1;
}
}
int
MRWInit(MRWLOCK * mrwl)
{
static pthread_mutex_t mi = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t ci = PTHREAD_COND_INITIALIZER;
mrwl->mrw_mutex = mi;
mrwl->mrw_cond = ci;
mrwl->mrw_rnum = 0;
return 0;
}
/* MODELINES */
/* DO NOT EDIT BELOW THIS COMMENT */
/* Modelines are added by 'make pretty' */
/* -*- Mode: C; c-basic-offset: 2; indent-tabs-mode: nil; -*- */
/* vi:set ts=2 sts=2 sw=2 expandtab: */
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