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/* Support for thread stuff.
*
* JC & KM 9/5/94
* Modified:
* 28/11/94 JC
* - return(0) missing from tidy_thread_info()
* 4/8/99 RP JC
* - reorganised for POSIX
* 28/3/11
* - moved to vips_ namespace
*/
/*
This file is part of VIPS.
VIPS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
*/
/*
#define DEBUG_IO
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <vips/vips.h>
#include <vips/thread.h>
void
vips_semaphore_init( VipsSemaphore *s, int v, char *name )
{
s->v = v;
s->name = name;
#ifdef HAVE_THREADS
s->mutex = g_mutex_new();
s->cond = g_cond_new();
#endif /*HAVE_THREADS*/
}
void
vips_semaphore_destroy( VipsSemaphore *s )
{
#ifdef HAVE_THREADS
VIPS_FREEF( g_mutex_free, s->mutex );
VIPS_FREEF( g_cond_free, s->cond );
#endif /*HAVE_THREADS*/
}
/* Add n to the semaphore and signal any threads that are blocked waiting
* a change.
*/
int
vips_semaphore_upn( VipsSemaphore *s, int n )
{
int value_after_op;
#ifdef HAVE_THREADS
g_mutex_lock( s->mutex );
#endif /*HAVE_THREADS*/
s->v += n;
value_after_op = s->v;
#ifdef HAVE_THREADS
g_mutex_unlock( s->mutex );
g_cond_signal( s->cond );
#endif /*HAVE_THREADS*/
#ifdef DEBUG_IO
printf( "vips_semaphore_upn(\"%s\",%d) = %d\n",
s->name, n, value_after_op );
if( value_after_op > 1 )
vips_error( "vips_semaphore_upn", "up over 1!" );
#endif /*DEBUG_IO*/
return( value_after_op );
}
/* Increment the semaphore.
*/
int
vips_semaphore_up( VipsSemaphore *s )
{
return( vips_semaphore_upn( s, 1 ) );
}
/* Wait for sem>n, then subtract n.
*/
int
vips_semaphore_downn( VipsSemaphore *s, int n )
{
int value_after_op;
#ifdef HAVE_THREADS
g_mutex_lock( s->mutex );
while( s->v < n )
g_cond_wait( s->cond, s->mutex );
#endif /*HAVE_THREADS*/
s->v -= n;
value_after_op = s->v;
#ifdef HAVE_THREADS
g_mutex_unlock( s->mutex );
#endif /*HAVE_THREADS*/
#ifdef DEBUG_IO
printf( "vips_semaphore_downn(\"%s\",%d): %d\n",
s->name, n, value_after_op );
#endif /*DEBUG_IO*/
return( value_after_op );
}
/* Wait for sem > 0, then decrement.
*/
int
vips_semaphore_down( VipsSemaphore *s )
{
return( vips_semaphore_downn( s, 1 ) );
}
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