Digital's C++ Header-Only Stack-Based Finite State Machine

This Finite State Machine utilised State-Based functionality to manage its states. (This type of StateMachine is also called a SFSM.)

More information on SFSM's can be found here.

Currently the states have OnEntry(), OnUpdate(), OnExit(), and IfFrom() functionality implemented.

The SFSM is written in C++, is header only, currently exists out of two files and has (Doxygen) documentation.

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Basic Usage:

To use the SFSM, the user has to create a StateMachine and the States with functionality. Both the StateMachine and the States must be inside of a Class. To then update the StateMachine, the user has to call the Update() function or UPDATE_STATEMACHINE macro.

Since this SFSM uses templates, the States can easily get to their Owner class or Owner StateMachine with the GetOwner() and GetFSM() functions. Both functions return a pointer to their objects.

• CreateState(); Constructs a State, so that the StateMachine can use it. (Allocated State will be tracked by the StateMachine. When the StateMachine gets destroyed, the states will as well.)
  
  
• Push(); Pushes a State on the stack and will be the topmost State after the push.
• Pop(); Removes/Pops the topmost State of the stack.
• ClearStateStack(); Removes all States of the Stack.
  
  
• SetEnabled(); Enables/Disables the StateMachine.
  • When the StateMachine is disabled, the StateMachine will not update its States until it gets enabled.
• SetLocked(); Locks/Unlocks the StateMachine.
  • When the StateMachine is locked, the StateMachine will continue to update its States, but you cannot Push a State, Pop a State, or Clear the stack, until the StateMachine gets unlocked.

Here you can find a code example on how to use the system.

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Notes:

• Pushing/Popping/Clearing States only adds/removes a pointer of the State to the Stack of the StateMachine.
• The functions OnEntry(), OnExit(), and IfFrom() function get immediately called when either pushing or popping states.
• The call order When pushing a State; OnExit() of top most State > Push new topmost State > OnEntry() of new topmost State, IfFrom() of new topmost State.
• The call order when popping; OnExit() of topmost State > Pop of topmost State > OnEntry() of new topmost State, IfFrom() of new State.

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License:

Digital's C++ Header-Only Stack-Based Finite State Machine is licensed under the Apache License 2.0.

Here you can find more information about the license.