table.cpp

Quantum Platform(QP) is a family of very lightweight, state machine-based frameworks for embedded sy

//////////////////////////////////////////////////////////////////////////////
// Product: QDPP example
// Last Updated for Version: 3.2.04
// Date of the Last Update:  Nov 23, 2006
//
//                    Q u a n t u m     L e a P s
//                    ---------------------------
//                    innovating embedded systems
//
// Copyright (C) 2002-2006 Quantum Leaps, LLC. All rights reserved.
//
// This software may be distributed and modified under the terms of the GNU
// General Public License version 2 (GPL) as published by the Free Software
// Foundation and appearing in the file GPL.TXT included in the packaging of
// this file. Please note that GPL Section 2[b] requires that all works based
// on this software must also be made publicly available under the terms of
// the GPL ("Copyleft").
//
// Alternatively, this software may be distributed and modified under the
// terms of Quantum Leaps commercial licenses, which expressly supersede
// the GPL and are specifically designed for licensees interested in
// retaining the proprietary status of their code.
//
// Contact information:
// Quantum Leaps Web site:  http://www.quantum-leaps.com
// e-mail:                  [e-mail]
//////////////////////////////////////////////////////////////////////////////
#include "qf_port.h"
#include "qassert.h"
#include "qdpp.h"

#include <stdlib.h>

Q_DEFINE_THIS_FILE

// Public-scope objects ------------------------------------------------------
QActive *QDPP_table;

// local objects -------------------------------------------------------------
class Table : public QActive {
private:
    uint8_t fork_[N];
    uint8_t isHungry_[N];

public:
    Table();

protected:
    static void initial(Table *me, QEvent const *e);
    static QSTATE serving(Table *me, QEvent const *e);

    #define RIGHT(n_) ((uint8_t)(((n_) + (N - 1)) % N))
    #define LEFT(n_)  ((uint8_t)(((n_) + 1) % N))
    enum { FREE = 0, USED = 1 };

private:
    friend void tableStart(uint8_t prio,
                           QEvent const *qSto[], uint32_t qLen);
};

//............................................................................
void tableStart(uint8_t prio,
                QEvent const *qSto[], uint32_t qLen)
{
    static Table table;
    QDPP_table = &table;                              // initialize the global
    table.start(prio,
                qSto, qLen,
                (void *)0,                          // no thread-local storage
                0,                         // this thread does not use the FPU
                (QEvent *)0);
}
//............................................................................
Table::Table() : QActive((QState)&Table::initial) {
    QDPP_table = this;                       // initialize the global
}
//............................................................................
void Table::initial(Table *me, QEvent const *) {
    uint8_t n;
    me->subscribe(HUNGRY_SIG);
    me->subscribe(DONE_SIG);
    me->subscribe(TERMINATE_SIG);
    for (n = 0; n < N; ++n) {
        me->fork_[n] = FREE;
        me->isHungry_[n] = 0;
    }
    Q_INIT(&Table::serving);
}
//............................................................................
QSTATE Table::serving(Table *me, QEvent const *e) {
    uint8_t n, m;
    TableEvt *pe;

    switch (e->sig) {
        case HUNGRY_SIG: {
            busyDelay();
            n = ((TableEvt *)e)->philNum;
            Q_ASSERT(n < N && !me->isHungry_[n]);
            displyPhilStat(n, "hungry  ");
            m = LEFT(n);
            if (me->fork_[m] == FREE && me->fork_[n] == FREE) {
                me->fork_[m] = me->fork_[n] = USED;
                pe = Q_NEW(TableEvt, EAT_SIG);
                pe->philNum = n;
                QF::publish(pe);
                displyPhilStat(n, "eating  ");
            }
            else {
                me->isHungry_[n] = 1;
            }
            return 0;
        }
        case DONE_SIG: {
            busyDelay();
            n = ((TableEvt *)e)->philNum;
            Q_ASSERT(n < N);
            displyPhilStat(n, "thinking");
            me->fork_[LEFT(n)] = me->fork_[n] = FREE;
            m = RIGHT(n);                          // check the right neighbor
            if (me->isHungry_[m] && me->fork_[m] == FREE) {
                me->fork_[n] = me->fork_[m] = USED;
                me->isHungry_[m] = 0;
                pe = Q_NEW(TableEvt, EAT_SIG);
                pe->philNum = m;
                QF::publish(pe);
                displyPhilStat(m, "eating  ");
            }
            m = LEFT(n);                            // check the left neighbor
            n = LEFT(m);
            if (me->isHungry_[m] && me->fork_[n] == FREE) {
                me->fork_[m] = me->fork_[n] = USED;
                me->isHungry_[m] = 0;
                pe = Q_NEW(TableEvt, EAT_SIG);
                pe->philNum = m;
                QF::publish(pe);
                displyPhilStat(m, "eating  ");
            }
            return 0;
        }
        case TERMINATE_SIG: {
            QF::exit();
            return 0;
        }
    }
    return (QSTATE)&QHsm::top;
}