// State machine
//
// Simplified code as example for a state machine.
//
// by feyd//godX.de
#include <string>
#include <stdio.h>
// State class waiting for "hello" followed by username "user" and password "mypassword"
// if everything was correct the state will reach "authenticated"
// if the chain is broken (in "hello" or "password" state) the state will enter "disconnected"
// after valid authentication the state machine will wait for "disconnect" keyword and enter the "disconnected" state
class CStateMachine
{
enum {
STATE_CONNECT = 0,
STATE_USERNAME,
STATE_PASSWORD,
STATE_AUTHENTICATED,
STATE_DISCONNECTED,
STATE_MAX
};
public:
CStateMachine() : m_nCurrentState(STATE_CONNECT) {}
virtual ~CStateMachine() {}
void Input(const std::string& sInput)
{
switch(m_nCurrentState)
{
case STATE_CONNECT:
if(sInput.compare("hello")==0)
{
m_nCurrentState = STATE_USERNAME;
} else {
m_nCurrentState = STATE_DISCONNECTED;
}
break;
case STATE_USERNAME:
// store username
m_sUsername = sInput;
m_nCurrentState = STATE_PASSWORD;
break;
case STATE_PASSWORD:
// check username and password
if(m_sUsername=="user" && sInput=="mypassword")
{
m_nCurrentState = STATE_AUTHENTICATED;
} else {
m_nCurrentState = STATE_DISCONNECTED;
}
break;
case STATE_AUTHENTICATED:
if(sInput.compare("disconnect")==0)
{
m_nCurrentState = STATE_DISCONNECTED;
}
case STATE_DISCONNECTED:
break;
default:;
};
}
void Output()
{
switch(m_nCurrentState)
{
case STATE_CONNECT: printf("CONNECT "); break;
case STATE_USERNAME: printf("USERNAME "); break;
case STATE_PASSWORD: printf("PASSWORD "); break;
case STATE_AUTHENTICATED: printf("AUTHENTICATED"); break;
case STATE_DISCONNECTED: printf("DISCONNECTED "); break;
default: printf("Unknown State"); break;
};
}
int GetCurrentState() const
{
return m_nCurrentState;
}
protected:
int m_nCurrentState;
std::string m_sUsername;
};
// Application entry point (from libc)
int main(int argc, const char* argv[])
{
printf("State machine example...\r\n\r\n");
{
CStateMachine stateMachine;
for(int n=1; n<argc; n++)
{
printf(" (%3d) %10s: ", n, argv[n]);
stateMachine.Output();
printf(" -> ");
stateMachine.Input(argv[n]);
stateMachine.Output();
printf("\r\n");
}
}
}
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