| /* 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 |
| */ |
| |
| /* |
| |
| 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> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| void |
| im_semaphore_init( im_semaphore_t *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 |
| im_semaphore_destroy( im_semaphore_t *s ) |
| { |
| #ifdef HAVE_THREADS |
| IM_FREEF( g_mutex_free, s->mutex ); |
| IM_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 |
| im_semaphore_upn( im_semaphore_t *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( "im_semaphore_upn(\"%s\",%d) = %d\n", |
| s->name, n, value_after_op ); |
| if( value_after_op > 1 ) |
| im_errormsg( "up over 1!" ); |
| #endif /*DEBUG_IO*/ |
| |
| return( value_after_op ); |
| } |
| |
| /* Increment the semaphore. |
| */ |
| int |
| im_semaphore_up( im_semaphore_t *s ) |
| { |
| return( im_semaphore_upn( s, 1 ) ); |
| } |
| |
| /* Wait for sem>n, then subtract n. |
| */ |
| int |
| im_semaphore_downn( im_semaphore_t *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( "im_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 |
| im_semaphore_down( im_semaphore_t *s ) |
| { |
| return( im_semaphore_downn( s, 1 ) ); |
| } |