c – 状态机实现

我们可以从两种起始状态中的一种开始,但我们必须触及握手的所有4种状态.从那里,我们可以传输数据的有效载荷或接收数据的有效载荷.然后,我们回到原来的起始状态.

握手：

– > StartingState1 – > FinalState1 – > StartingState2 – > FinalState2

– > StartingState2 – > FinalState2 – > StartingState1 – > FinalState1

有效负载转移：

– > SendPayload – > SendEnd – > StartingState？

– > ReceivePayload – > ReceiveEnd – > StartingState？

下面的代码代表了我当前的架构.不幸的是,在每个过程结束时,我没有从州内获得足够的信息来了解我应该触及的下一个状态.

有没有人对如何根据我的要求改进这种架构有任何建议？

谢谢,
?PaulH

class MyMachine;
class Payload;

class IState
{
    MyMachine* context_;

    IState( MyMachine* context ) : context_( context) {};

    virtual void Consume( byte data );

    void ChangeState( IState* state )
    {
        context_->SetState( state );
    }
}

class FinalState1 : IState
{
    void Consume( byte data )
    {
        // Either go to StartingState1,SendPayload,or ReceivePayload.
        // How can I tell from within the context of this state where I 
        // should go?
    }
}

class StartingState1 : IState
{
    void Consume( byte data )
    {
        if ( /*some condition*/ )
        {
            ChangeState( new FinalState1( context_ ) );
        } 
    }
}

class MyMachine
{
    IState* state_;
    Payload* payload_;

    void Start1( Mode mode )
    {
        state_ = new StartingState1( this );
    }

    void Start2( Mode mode )
    {
        state_ = new StartingState2( this );
    }

    void Consume( byte data )
    {
        state_->Consume( data );
    }

    void SetPayload( const Payload* payload )
    {
        payload_ = payload;
    }

    const Payload* GetPayload()
    {
        return payload_;
    }

    void SetState( State* state )
    {
        delete state_;
        state_ = state;
    }
}

// get a byte of data from some source
byte GetData();

void main()
{
    MyMachine machine;
    Payload payload;
    machine.SetPayload( payload );
    machine.Start1( Mode::SendPayload );

    // could also call:
    // machine.Start1( Mode::ReceivePayload );
    // machine.Start2( Mode::SendPayload );
    // machine.Start2( Mode::ReceivePayload );

    for(;;)
    {
        machine.Consume( GetData() );
    }
}