spot::state_product Class Reference

A state for spot::twa_product. More...

#include <spot/twa/twaproduct.hh>

Inheritance diagram for spot::state_product:

Collaboration diagram for spot::state_product:

Public Member Functions
	state_product (const state *left, const state *right, fixed_size_pool< pool_type::Safe > *pool)
	Constructor. More...
virtual void	destroy () const override
	Release a state. More...
const state *	left () const
const state *	right () const
virtual int	compare (const state *other) const override
	Compares two states (that come from the same automaton). More...
virtual size_t	hash () const override
	Hash a state. More...
virtual state_product *	clone () const override
	Duplicate a state. More...

Detailed Description

A state for spot::twa_product.

This state is in fact a pair of state: the state from the left automaton and that of the right.

Constructor & Destructor Documentation

state_product()

spot::state_product::state_product ( const state *  left, const state *  right, fixed_size_pool< pool_type::Safe > *  pool  )

inline

Constructor.

Parameters

left	The state from the left automaton.
right	The state from the right automaton.
pool	The pool from which the state was allocated. These states are acquired by spot::state_product, and will be destroyed on destruction.

Member Function Documentation

clone()

virtual state_product * spot::state_product::clone ( ) const

overridevirtual

Duplicate a state.

Implements spot::state.

compare()

virtual int spot::state_product::compare ( const state *  other ) const

overridevirtual

Compares two states (that come from the same automaton).

This method returns an integer less than, equal to, or greater than zero if this is found, respectively, to be less than, equal to, or greater than other according to some implicit total order.

This method should not be called to compare states from different automata.

See also

spot::state_ptr_less_than

Implements spot::state.

destroy()

virtual void spot::state_product::destroy ( ) const

overridevirtual

Release a state.

Methods from the tgba or twa_succ_iterator always return a new state that you should deallocate with this function. Before Spot 0.7, you had to "delete" your state directly. Starting with Spot 0.7, you should update your code to use this function instead. destroy() usually calls delete, except in subclasses that destroy() to allow better memory management (e.g., no memory allocation for explicit automata).

Reimplemented from spot::state.

hash()

virtual size_t spot::state_product::hash ( ) const

overridevirtual

Hash a state.

This method returns an integer that can be used as a hash value for this state.

Note that the hash value is guaranteed to be unique for all equal states (in compare()'s sense) for only as long as one of these states exists. So it's OK to use a spot::state as a key in a hash_map because the mere use of the state as a key in the hash will ensure the state continues to exist.

However if you create the state, get its hash key, delete the state, recreate the same state, and get its hash key, you may obtain two different hash keys if the same state were not already used elsewhere. In practice this weird situation can occur only when the state is BDD-encoded, because BDD numbers (used to build the hash value) can be reused for other formulas. That probably doesn't matter, since the hash value is meant to be used in a hash_map, but it had to be noted.

Implements spot::state.

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The documentation for this class was generated from the following file:

• spot/twa/twaproduct.hh