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spot::state Class Reference

Abstract class for states. More...

#include <state.hh>

Inheritance diagram for spot::state:

Inheritance graph
[legend]
List of all members.

Public Member Functions

virtual int compare (const state *other) const=0
 Compares two states (that come from the same automaton).

virtual size_t hash () const=0
 Hash a state.

virtual stateclone () const=0
 Duplicate a state.

virtual ~state ()

Detailed Description

Abstract class for states.


Constructor & Destructor Documentation

virtual spot::state::~state  )  [inline, virtual]
 


Member Function Documentation

virtual state* spot::state::clone  )  const [pure virtual]
 

Duplicate a state.

Implemented in spot::state_bdd, spot::state_explicit, and spot::state_product.

virtual int spot::state::compare const state other  )  const [pure virtual]
 

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

Implemented in spot::state_bdd, and spot::state_product.

virtual size_t spot::state::hash  )  const [pure virtual]
 

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 has long has 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.

Implemented in spot::state_bdd, spot::state_explicit, and spot::state_product.


The documentation for this class was generated from the following file:
Generated on Mon Mar 8 23:31:58 2004 for spot by doxygen 1.3.5