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53d2e0a7e0
git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@27732 72102866-910b-0410-8b05-ffd578937521
152 lines
3.2 KiB
Objective-C
152 lines
3.2 KiB
Objective-C
/*
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diningPhilosophers.h
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Five hungry philosophers testing locks and threads
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This program loops indefinitely.
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Copyright (C) 1996 Free Software Foundation, Inc.
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Author: Scott Christley <scottc@net-community.com>
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Date: 1996
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This file is part of the GNUstep Application Kit Library.
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This file is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public
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License as published by the Free Software Foundation; either
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version 3 of the License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public
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License along with this file; if not, write to the Free
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Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111 USA.
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*/
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#include <Foundation/NSLock.h>
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#include <Foundation/NSThread.h>
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#include <Foundation/NSAutoreleasePool.h>
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#include <Foundation/NSValue.h>
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// Conditions
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#define NO_FOOD 1
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#define FOOD_SERVED 2
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// NSLocks ... umm I mean forks
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id forks[5];
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id fork_lock;
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//
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// A class of hungry philosophers
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//
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@interface Philosopher : NSObject
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{
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int chair;
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}
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// Instance methods
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- (void)sitAtChair:(NSNumber*)position;
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- (int)chair;
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@end
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@implementation Philosopher
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// Instance methods
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- (void)sitAtChair:(NSNumber*)position
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{
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int i;
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// Sit down
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chair = [position intValue];
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// Its a constant battle to feed yourself
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while (1)
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{
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[fork_lock lockWhenCondition:FOOD_SERVED];
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// Get the fork to our left
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[forks[chair] lockWhenCondition:FOOD_SERVED];
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// Get the fork to our right
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[forks[(chair + 1) % 5] lockWhenCondition:FOOD_SERVED];
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[fork_lock unlock];
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// Start eating!
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printf("Philosopher %d can start eating.\n", chair); fflush(stdout);
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for (i = 0;i < 100000; ++i)
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{
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if ((i % 10000) == 0)
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printf("Philosopher %d is eating.\n", chair); fflush(stdout);
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}
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// Done eating
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printf("Philosopher %d is done eating.\n", chair); fflush(stdout);
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// Drop the fork to our left
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[forks[chair] unlock];
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// Drop the fork to our right
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[forks[(chair + 1) % 5] unlock];
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// Wait until we are hungry again
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for (i = 0;i < 1000000 * (chair + 1); ++i) ;
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}
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// We never get here, but this is what we should do
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[NSThread exit];
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}
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- (int)chair
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{
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return chair;
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}
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@end
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//
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// my main for the test app
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//
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int main()
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{
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NSAutoreleasePool *arp = [NSAutoreleasePool new];
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int i;
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id p[5];
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// Create the locks
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for (i = 0;i < 5; ++i)
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{
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forks[i] = [[NSConditionLock alloc]
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initWithCondition:NO_FOOD];
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[forks[i] lock];
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}
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fork_lock = [[NSConditionLock alloc]
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initWithCondition:NO_FOOD];
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[fork_lock lock];
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// Create the philosophers
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for (i = 0;i < 5; ++i)
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p[i] = [[Philosopher alloc] init];
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// Have them sit at the table
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for (i = 0;i < 5; ++i)
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[NSThread detachNewThreadSelector:@selector(sitAtChair:)
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toTarget:p[i] withObject: [NSNumber numberWithInt: i]];
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// Now let them all eat
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[fork_lock unlockWithCondition:FOOD_SERVED];
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for (i = 0;i < 5; ++i)
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[forks[i] unlockWithCondition:FOOD_SERVED];
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while (1);
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[arp release];
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}
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