166 lines
4.0 KiB
C
166 lines
4.0 KiB
C
/*
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* Copyright (c) 2004-2005, Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the protothreads library.
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*
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* Author: Adam Dunkels <adam@sics.se>
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*
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* $Id: example-buffer.c,v 1.5 2005/10/07 05:21:33 adam Exp $
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*/
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#ifdef _WIN32
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#include <windows.h>
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#else
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#include <unistd.h>
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#endif
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#include <stdio.h>
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#include "pt-sem.h"
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#define NUM_ITEMS 32
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#define BUFSIZE 8
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static int buffer[BUFSIZE];
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static int bufptr;
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static void
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add_to_buffer(int item)
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{
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printf("Item %d added to buffer at place %d\n", item, bufptr);
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buffer[bufptr] = item;
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bufptr = (bufptr + 1) % BUFSIZE;
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}
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static int
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get_from_buffer(void)
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{
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int item;
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item = buffer[bufptr];
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printf("Item %d retrieved from buffer at place %d\n",
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item, bufptr);
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bufptr = (bufptr + 1) % BUFSIZE;
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return item;
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}
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static int
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produce_item(void)
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{
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static int item = 0;
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printf("Item %d produced\n", item);
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return item++;
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}
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static void
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consume_item(int item)
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{
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printf("Item %d consumed\n", item);
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}
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static struct pt_sem full, empty;
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static
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PT_THREAD(producer(struct pt *pt))
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{
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static int produced;
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PT_BEGIN(pt);
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for(produced = 0; produced < NUM_ITEMS; ++produced) {
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PT_SEM_WAIT(pt, &full);
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add_to_buffer(produce_item());
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PT_SEM_SIGNAL(pt, &empty);
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}
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PT_END(pt);
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}
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static
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PT_THREAD(consumer(struct pt *pt))
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{
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static int consumed;
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PT_BEGIN(pt);
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for(consumed = 0; consumed < NUM_ITEMS; ++consumed) {
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PT_SEM_WAIT(pt, &empty);
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consume_item(get_from_buffer());
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PT_SEM_SIGNAL(pt, &full);
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}
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PT_END(pt);
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}
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static
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PT_THREAD(driver_thread(struct pt *pt))
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{
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static struct pt pt_producer, pt_consumer;
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PT_BEGIN(pt);
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PT_SEM_INIT(&empty, 0);
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PT_SEM_INIT(&full, BUFSIZE);
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PT_INIT(&pt_producer);
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PT_INIT(&pt_consumer);
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PT_WAIT_THREAD(pt, producer(&pt_producer) &
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consumer(&pt_consumer));
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PT_END(pt);
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}
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int
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main(void)
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{
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struct pt driver_pt;
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PT_INIT(&driver_pt);
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while(PT_SCHEDULE(driver_thread(&driver_pt))) {
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/*
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* When running this example on a multitasking system, we must
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* give other processes a chance to run too and therefore we call
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* usleep() resp. Sleep() here. On a dedicated embedded system,
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* we usually do not need to do this.
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*/
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#ifdef _WIN32
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Sleep(0);
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#else
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usleep(10);
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#endif
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}
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return 0;
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}
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