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