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afsm
is a finite state machine C++11 library designed for usage in multithreaded asynchronous environment.
The afsm
library was inspired by ::boost::msm
library and implemented so that the migration from ::boost::msm
was a bunch of search and replace operations. The main motivation was to create a thread-safe FSM library and to achieve decent compile times for large and complex state machines not sacrificing performance. A state machine defined with afms
library compiles several times faster than same library defined with ::boost::msm
and has similar (or better) performance. You can find some benchmark results here.
- Statechart features
- Hierarchical states
- Entry and exit actions
- Internal transitions
- Transition actions
- Transition guards (conditions)
- State history
- Event deferring
- Orthogonal regions
- Statechart extensions
- Optional event priority
- Optional common base for states and easy definition of dispatching common interface calls to current state
- Pushdown automaton
- Compile-time checks
- Thread safety
- Exception safety
- No vtables (unless common base feature is used)
- Header only
- Relatively fast compile time
- No external dependencies except STL
- State machine persistense
Here is a UML diagram of a trivial state machine and source code that it is mapped to.
#include <afsm/fsm.hpp>
// Events
struct start {};
struct stop {};
// State machine definition
struct minimal_def : ::afsm::def::state_machine<minimal_def> {
//@{
/** @name States */
struct initial : state<initial> {};
struct running : state<running> {};
struct terminated : terminal_state<terminated> {};
//@}
using initial_state = initial;
using transitions = transition_table<
/* State Event Next */
tr< initial, start, running >,
tr< running, stop, terminated >
>;
};
// State machine object
using minimal = ::afsm::state_machine<minimal_def>;
void use()
{
mimimal fsm;
fsm.process_event(start{});
fsm.process_event(stop{});
}
You can find a tutorial covering most of basic features here.
TODO doxygen generated documentation.
The library is header only and doesn't requre build or installation. Just add the afsm/include
and lib/meta/include
directories under the root of this repository to your include paths.
You can add the library to your project as a subtree, e.g. lib/afsm
, and in your root CMakeLists.txt
file just do the following:
add_subdirectory(lib/afsm)
include_directories(${AFSM_INCLUDE_DIRS})
TODO write docs on gitrc subtree commands and link to the repository
git clone git@github.com:zmij/afsm.git
mkdir afsm/build
cd afsm/build
cmake ..
sudo make install
find_package(AFSM REQUIRED) # Will set AFSM_INCLUDE_DIRS variable
The project is mostly developed as a part of other projects (pg_async, PostgreSQL asynchronous driver, wire, an RPC library for C++) which are in turn developed as a part of a bigger commercial project.
- Home
- Tutorial
-
Concepts
- State Hierarchy
- Entry/Exit Actions
- Transition Actions
- Transition Guards
- Internal Transitions
- Default Transitions
- Event Deferring
- History
- Orthogonal Regions
- Event Priority
- Common Base
- Thread Safety
- Exception Safety Guarantees
- Under the Hood
- Event Processing
- Performance