Notes on version 6.3.

[ragel.git] / ragel / fsmbase.cpp

/*
 *  Copyright 2001-2007 Adrian Thurston <thurston@cs.queensu.ca>
 */

/*  This file is part of Ragel.
 *
 *  Ragel is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 * 
 *  Ragel is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with Ragel; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */

#include <string.h>
#include <assert.h>
#include "fsmgraph.h"

/* Simple singly linked list append routine for the fill list. The new state
 * goes to the end of the list. */
void MergeData::fillListAppend( StateAp *state )
{
        state->alg.next = 0;

        if ( stfillHead == 0 ) {
                /* List is empty, state becomes head and tail. */
                stfillHead = state;
                stfillTail = state;
        }
        else {
                /* List is not empty, state goes after last element. */
                stfillTail->alg.next = state;
                stfillTail = state;
        }
}

/* Graph constructor. */
FsmAp::FsmAp()
:
        /* No start state. */
        startState(0),
        errState(0),

        /* Misfit accounting is a switch, turned on only at specific times. It
         * controls what happens when states have no way in from the outside
         * world.. */
        misfitAccounting(false)
{
}

/* Copy all graph data including transitions. */
FsmAp::FsmAp( const FsmAp &graph )
:
        /* Lists start empty. Will be filled by copy. */
        stateList(),
        misfitList(),

        /* Copy in the entry points, 
         * pointers will be resolved later. */
        entryPoints(graph.entryPoints),
        startState(graph.startState),
        errState(0),

        /* Will be filled by copy. */
        finStateSet(),
        
        /* Misfit accounting is only on during merging. */
        misfitAccounting(false)
{
        /* Create the states and record their map in the original state. */
        StateList::Iter origState = graph.stateList;
        for ( ; origState.lte(); origState++ ) {
                /* Make the new state. */
                StateAp *newState = new StateAp( *origState );

                /* Add the state to the list.  */
                stateList.append( newState );

                /* Set the mapsTo item of the old state. */
                origState->alg.stateMap = newState;
        }
        
        /* Derefernce all the state maps. */
        for ( StateList::Iter state = stateList; state.lte(); state++ ) {
                for ( TransList::Iter trans = state->outList; trans.lte(); trans++ ) {
                        /* The points to the original in the src machine. The taget's duplicate
                         * is in the statemap. */
                        StateAp *toState = trans->toState != 0 ? trans->toState->alg.stateMap : 0;

                        /* Attach The transition to the duplicate. */
                        trans->toState = 0;
                        attachTrans( state, toState, trans );
                }

                /* Fix the eofTarg, if set. */
                if ( state->eofTarget != 0 )
                        state->eofTarget = state->eofTarget->alg.stateMap;
        }

        /* Fix the state pointers in the entry points array. */
        EntryMapEl *eel = entryPoints.data;
        for ( int e = 0; e < entryPoints.length(); e++, eel++ ) {
                /* Get the duplicate of the state. */
                eel->value = eel->value->alg.stateMap;

                /* Foreign in transitions must be built up when duping machines so
                 * increment it here. */
                eel->value->foreignInTrans += 1;
        }

        /* Fix the start state pointer and the new start state's count of in
         * transiions. */
        startState = startState->alg.stateMap;
        startState->foreignInTrans += 1;

        /* Build the final state set. */
        StateSet::Iter st = graph.finStateSet; 
        for ( ; st.lte(); st++ ) 
                finStateSet.insert((*st)->alg.stateMap);
}

/* Deletes all transition data then deletes each state. */
FsmAp::~FsmAp()
{
        /* Delete all the transitions. */
        for ( StateList::Iter state = stateList; state.lte(); state++ ) {
                /* Iterate the out transitions, deleting them. */
                state->outList.empty();
        }

        /* Delete all the states. */
        stateList.empty();
}

/* Set a state final. The state has its isFinState set to true and the state
 * is added to the finStateSet. */
void FsmAp::setFinState( StateAp *state )
{
        /* Is it already a fin state. */
        if ( state->stateBits & STB_ISFINAL )
                return;
        
        state->stateBits |= STB_ISFINAL;
        finStateSet.insert( state );
}

/* Set a state non-final. The has its isFinState flag set false and the state
 * is removed from the final state set. */
void FsmAp::unsetFinState( StateAp *state )
{
        /* Is it already a non-final state? */
        if ( ! (state->stateBits & STB_ISFINAL) )
                return;

        /* When a state looses its final state status it must relinquish all the
         * properties that are allowed only for final states. */
        clearOutData( state );

        state->stateBits &= ~ STB_ISFINAL;
        finStateSet.remove( state );
}

/* Set and unset a state as the start state. */
void FsmAp::setStartState( StateAp *state )
{
        /* Sould change from unset to set. */
        assert( startState == 0 );
        startState = state;

        if ( misfitAccounting ) {
                /* If the number of foreign in transitions is about to go up to 1 then
                 * take it off the misfit list and put it on the head list. */
                if ( state->foreignInTrans == 0 )
                        stateList.append( misfitList.detach( state ) );
        }

        /* Up the foreign in transitions to the state. */
        state->foreignInTrans += 1;
}

void FsmAp::unsetStartState()
{
        /* Should change from set to unset. */
        assert( startState != 0 );

        /* Decrement the entry's count of foreign entries. */
        startState->foreignInTrans -= 1;

        if ( misfitAccounting ) {
                /* If the number of foreign in transitions just went down to 0 then take
                 * it off the main list and put it on the misfit list. */
                if ( startState->foreignInTrans == 0 )
                        misfitList.append( stateList.detach( startState ) );
        }

        startState = 0;
}

/* Associate an id with a state. Makes the state a named entry point. Has no
 * effect if the entry point is already mapped to the state. */
void FsmAp::setEntry( int id, StateAp *state )
{
        /* Insert the id into the state. If the state is already labelled with id,
         * nothing to do. */
        if ( state->entryIds.insert( id ) ) {
                /* Insert the entry and assert that it succeeds. */
                entryPoints.insertMulti( id, state );

                if ( misfitAccounting ) {
                        /* If the number of foreign in transitions is about to go up to 1 then
                         * take it off the misfit list and put it on the head list. */
                        if ( state->foreignInTrans == 0 )
                                stateList.append( misfitList.detach( state ) );
                }

                /* Up the foreign in transitions to the state. */
                state->foreignInTrans += 1;
        }
}

/* Remove the association of an id with a state. The state looses it's entry
 * point status. Assumes that the id is indeed mapped to state. */
void FsmAp::unsetEntry( int id, StateAp *state )
{
        /* Find the entry point in on id. */
        EntryMapEl *enLow = 0, *enHigh = 0;
        entryPoints.findMulti( id, enLow, enHigh );
        while ( enLow->value != state )
                enLow += 1;

        /* Remove the record from the map. */
        entryPoints.remove( enLow );

        /* Remove the state's sense of the link. */
        state->entryIds.remove( id );
        state->foreignInTrans -= 1;
        if ( misfitAccounting ) {
                /* If the number of foreign in transitions just went down to 0 then take
                 * it off the main list and put it on the misfit list. */
                if ( state->foreignInTrans == 0 )
                        misfitList.append( stateList.detach( state ) );
        }
}

/* Remove all association of an id with states. Assumes that the id is indeed
 * mapped to a state. */
void FsmAp::unsetEntry( int id )
{
        /* Find the entry point in on id. */
        EntryMapEl *enLow = 0, *enHigh = 0;
        entryPoints.findMulti( id, enLow, enHigh );
        for ( EntryMapEl *mel = enLow; mel <= enHigh; mel++ ) {
                /* Remove the state's sense of the link. */
                mel->value->entryIds.remove( id );
                mel->value->foreignInTrans -= 1;
                if ( misfitAccounting ) {
                        /* If the number of foreign in transitions just went down to 0
                         * then take it off the main list and put it on the misfit list. */
                        if ( mel->value->foreignInTrans == 0 )
                                misfitList.append( stateList.detach( mel->value ) );
                }
        }

        /* Remove the records from the entry points map. */
        entryPoints.removeMulti( enLow, enHigh );
}


void FsmAp::changeEntry( int id, StateAp *to, StateAp *from )
{
        /* Find the entry in the entry map. */
        EntryMapEl *enLow = 0, *enHigh = 0;
        entryPoints.findMulti( id, enLow, enHigh );
        while ( enLow->value != from )
                enLow += 1;
        
        /* Change it to the new target. */
        enLow->value = to;

        /* Remove from's sense of the link. */
        from->entryIds.remove( id );
        from->foreignInTrans -= 1;
        if ( misfitAccounting ) {
                /* If the number of foreign in transitions just went down to 0 then take
                 * it off the main list and put it on the misfit list. */
                if ( from->foreignInTrans == 0 )
                        misfitList.append( stateList.detach( from ) );
        }

        /* Add to's sense of the link. */
        if ( to->entryIds.insert( id ) != 0 ) {
                if ( misfitAccounting ) {
                        /* If the number of foreign in transitions is about to go up to 1 then
                         * take it off the misfit list and put it on the head list. */
                        if ( to->foreignInTrans == 0 )
                                stateList.append( misfitList.detach( to ) );
                }

                /* Up the foreign in transitions to the state. */
                to->foreignInTrans += 1;
        }
}


/* Clear all entry points from a machine. */
void FsmAp::unsetAllEntryPoints()
{
        for ( EntryMap::Iter en = entryPoints; en.lte(); en++ ) {
                /* Kill all the state's entry points at once. */
                if ( en->value->entryIds.length() > 0 ) {
                        en->value->foreignInTrans -= en->value->entryIds.length();

                        if ( misfitAccounting ) {
                                /* If the number of foreign in transitions just went down to 0
                                 * then take it off the main list and put it on the misfit
                                 * list. */
                                if ( en->value->foreignInTrans == 0 )
                                        misfitList.append( stateList.detach( en->value ) );
                        }

                        /* Clear the set of ids out all at once. */
                        en->value->entryIds.empty();
                }
        }

        /* Now clear out the entry map all at once. */
        entryPoints.empty();
}

/* Assigning an epsilon transition into final states. */
void FsmAp::epsilonTrans( int id )
{
        for ( StateSet::Iter fs = finStateSet; fs.lte(); fs++ )
                (*fs)->epsilonTrans.append( id );
}

/* Mark all states reachable from state. Traverses transitions forward. Used
 * for removing states that have no path into them. */
void FsmAp::markReachableFromHere( StateAp *state )
{
        /* Base case: return; */
        if ( state->stateBits & STB_ISMARKED )
                return;
        
        /* Set this state as processed. We are going to visit all states that this
         * state has a transition to. */
        state->stateBits |= STB_ISMARKED;

        /* Recurse on all out transitions. */
        for ( TransList::Iter trans = state->outList; trans.lte(); trans++ ) {
                if ( trans->toState != 0 )
                        markReachableFromHere( trans->toState );
        }
}

void FsmAp::markReachableFromHereStopFinal( StateAp *state )
{
        /* Base case: return; */
        if ( state->stateBits & STB_ISMARKED )
                return;
        
        /* Set this state as processed. We are going to visit all states that this
         * state has a transition to. */
        state->stateBits |= STB_ISMARKED;

        /* Recurse on all out transitions. */
        for ( TransList::Iter trans = state->outList; trans.lte(); trans++ ) {
                StateAp *toState = trans->toState;
                if ( toState != 0 && !toState->isFinState() )
                        markReachableFromHereStopFinal( toState );
        }
}

/* Mark all states reachable from state. Traverse transitions backwards. Used
 * for removing dead end paths in graphs. */
void FsmAp::markReachableFromHereReverse( StateAp *state )
{
        /* Base case: return; */
        if ( state->stateBits & STB_ISMARKED )
                return;
        
        /* Set this state as processed. We are going to visit all states with
         * transitions into this state. */
        state->stateBits |= STB_ISMARKED;

        /* Recurse on all items in transitions. */
        for ( TransInList::Iter trans = state->inList; trans.lte(); trans++ ) 
                markReachableFromHereReverse( trans->fromState );
}

/* Determine if there are any entry points into a start state other than the
 * start state. Setting starting transitions requires that the start state be
 * isolated. In most cases a start state will already be isolated. */
bool FsmAp::isStartStateIsolated()
{
        /* If there are any in transitions then the state is not isolated. */
        if ( startState->inList.head != 0 )
                return false;

        /* If there are any entry points then isolated. */
        if ( startState->entryIds.length() > 0 )
                return false;

        return true;
}

/* Bring in other's entry points. Assumes others states are going to be
 * copied into this machine. */
void FsmAp::copyInEntryPoints( FsmAp *other )
{
        /* Use insert multi because names are not unique. */
        for ( EntryMap::Iter en = other->entryPoints; en.lte(); en++ )
                entryPoints.insertMulti( en->key, en->value );
}


void FsmAp::unsetAllFinStates()
{
        for ( StateSet::Iter st = finStateSet; st.lte(); st++ )
                (*st)->stateBits &= ~ STB_ISFINAL;
        finStateSet.empty();
}

void FsmAp::setFinBits( int finStateBits )
{
        for ( int s = 0; s < finStateSet.length(); s++ )
                finStateSet.data[s]->stateBits |= finStateBits;
}


/* Tests the integrity of the transition lists and the fromStates. */
void FsmAp::verifyIntegrity()
{
        for ( StateList::Iter state = stateList; state.lte(); state++ ) {
                /* Walk the out transitions and assert fromState is correct. */
                for ( TransList::Iter trans = state->outList; trans.lte(); trans++ )
                        assert( trans->fromState == state );

                /* Walk the inlist and assert toState is correct. */
                for ( TransInList::Iter trans = state->inList; trans.lte(); trans++ ) 
                        assert( trans->toState == state );
        }
}

void FsmAp::verifyReachability()
{
        /* Mark all the states that can be reached 
         * through the set of entry points. */
        markReachableFromHere( startState );
        for ( EntryMap::Iter en = entryPoints; en.lte(); en++ )
                markReachableFromHere( en->value );

        /* Check that everything got marked. */
        for ( StateList::Iter st = stateList; st.lte(); st++ ) {
                /* Assert it got marked and then clear the mark. */
                assert( st->stateBits & STB_ISMARKED );
                st->stateBits &= ~ STB_ISMARKED;
        }
}

void FsmAp::verifyNoDeadEndStates()
{
        /* Mark all states that have paths to the final states. */
        for ( StateSet::Iter pst = finStateSet; pst.lte(); pst++ )
                markReachableFromHereReverse( *pst );

        /* Start state gets honorary marking. Must be done AFTER recursive call. */
        startState->stateBits |= STB_ISMARKED;

        /* Make sure everything got marked. */
        for ( StateList::Iter st = stateList; st.lte(); st++ ) {
                /* Assert the state got marked and unmark it. */
                assert( st->stateBits & STB_ISMARKED );
                st->stateBits &= ~ STB_ISMARKED;
        }
}

void FsmAp::depthFirstOrdering( StateAp *state )
{
        /* Nothing to do if the state is already on the list. */
        if ( state->stateBits & STB_ONLIST )
                return;

        /* Doing depth first, put state on the list. */
        state->stateBits |= STB_ONLIST;
        stateList.append( state );
        
        /* Recurse on everything ranges. */
        for ( TransList::Iter tel = state->outList; tel.lte(); tel++ ) {
                if ( tel->toState != 0 )
                        depthFirstOrdering( tel->toState );
        }
}

/* Ordering states by transition connections. */
void FsmAp::depthFirstOrdering()
{
        /* Init on state list flags. */
        for ( StateList::Iter st = stateList; st.lte(); st++ )
                st->stateBits &= ~STB_ONLIST;
        
        /* Clear out the state list, we will rebuild it. */
        int stateListLen = stateList.length();
        stateList.abandon();

        /* Add back to the state list from the start state and all other entry
         * points. */
        if ( errState != 0 )
                depthFirstOrdering( errState );
        depthFirstOrdering( startState );
        for ( EntryMap::Iter en = entryPoints; en.lte(); en++ )
                depthFirstOrdering( en->value );
        
        /* Make sure we put everything back on. */
        assert( stateListLen == stateList.length() );
}

/* Stable sort the states by final state status. */
void FsmAp::sortStatesByFinal()
{
        /* Move forward through the list and throw final states onto the end. */
        StateAp *state = 0;
        StateAp *next = stateList.head;
        StateAp *last = stateList.tail;
        while ( state != last ) {
                /* Move forward and load up the next. */
                state = next;
                next = state->next;

                /* Throw to the end? */
                if ( state->isFinState() ) {
                        stateList.detach( state );
                        stateList.append( state );
                }
        }
}

void FsmAp::setStateNumbers( int base )
{
        for ( StateList::Iter state = stateList; state.lte(); state++ )
                state->alg.stateNum = base++;
}


bool FsmAp::checkErrTrans( StateAp *state, TransAp *trans )
{
        /* Might go directly to error state. */
        if ( trans->toState == 0 )
                return true;

        if ( trans->prev == 0 ) {
                /* If this is the first transition. */
                if ( keyOps->minKey < trans->lowKey )
                        return true;
        }
        else {
                /* Not the first transition. Compare against the prev. */
                TransAp *prev = trans->prev;
                Key nextKey = prev->highKey;
                nextKey.increment();
                if ( nextKey < trans->lowKey )
                        return true; 
        }
        return false;
}

bool FsmAp::checkErrTransFinish( StateAp *state )
{
        /* Check if there are any ranges already. */
        if ( state->outList.length() == 0 )
                return true;
        else {
                /* Get the last and check for a gap on the end. */
                TransAp *last = state->outList.tail;
                if ( last->highKey < keyOps->maxKey )
                        return true;
        }
        return 0;
}

bool FsmAp::hasErrorTrans()
{
        bool result;
        for ( StateList::Iter st = stateList; st.lte(); st++ ) {
                for ( TransList::Iter tr = st->outList; tr.lte(); tr++ ) {
                        result = checkErrTrans( st, tr );
                        if ( result )
                                return true;
                }
                result = checkErrTransFinish( st );
                if ( result )
                        return true;
        }
        return false;
}