public DeterministicTrace([NotNull] DeterministicState startState, [NotNull] DeterministicState endState, [NotNull] IEnumerable <DeterministicTraceTransition> transitions)
{
Requires.NotNull(startState, nameof(startState));
Requires.NotNull(endState, nameof(endState));
Requires.NotNull(transitions, nameof(transitions));
_startState = startState;
_endState = endState;
_transitions = new List <DeterministicTraceTransition>(transitions);
}
public DeterministicTrace(DeterministicState startState, DeterministicState endState, IEnumerable <DeterministicTraceTransition> transitions)
{
Contract.Requires <ArgumentNullException>(startState != null, "startState");
Contract.Requires <ArgumentNullException>(endState != null, "endState");
Contract.Requires <ArgumentNullException>(transitions != null, "transitions");
_startState = startState;
_endState = endState;
_transitions = new List <DeterministicTraceTransition>(transitions);
}
public DeterministicTrace(DeterministicState startState, DeterministicState endState)
: this(startState, endState, Enumerable.Empty <DeterministicTraceTransition>())
{
}
public bool TryStepBackward()
{
if (_failedBackward || _beginningOfFile)
{
return(false);
}
if (_input.Index - _lookBehindPosition <= 0)
{
_beginningOfFile = true;
return(false);
}
IToken token = _input.LT(-1 - _lookBehindPosition);
if (token == null)
{
_beginningOfFile = true;
return(false);
}
int symbol = token.Type;
int symbolPosition = token.TokenIndex;
/*
* Update the non-deterministic trace
*/
Stopwatch updateTimer = Stopwatch.StartNew();
if (_lookAheadPosition == 0 && _lookBehindPosition == 0 && _contexts.Count == 0)
{
HashSet <InterpretTrace> initialContexts = new HashSet <InterpretTrace>(EqualityComparer <InterpretTrace> .Default);
/* create our initial set of states as the ones at the target end of a match transition
* that contains 'symbol' in the match set.
*/
List <Transition> transitions = new List <Transition>(_network.Transitions.Where(i => i.MatchesSymbol(symbol)));
foreach (var transition in transitions)
{
if (ExcludedStartRules.Contains(Network.StateRules[transition.SourceState.Id]))
{
continue;
}
if (ExcludedStartRules.Contains(Network.StateRules[transition.TargetState.Id]))
{
continue;
}
ContextFrame startContext = new ContextFrame(transition.TargetState, null, null, this);
ContextFrame endContext = new ContextFrame(transition.TargetState, null, null, this);
initialContexts.Add(new InterpretTrace(startContext, endContext));
}
_contexts.AddRange(initialContexts);
#if DFA
DeterministicState deterministicState = new DeterministicState(_contexts.Select(i => i.StartContext));
_deterministicTrace = new DeterministicTrace(deterministicState, deterministicState);
#endif
}
List <InterpretTrace> existing = new List <InterpretTrace>(_contexts);
_contexts.Clear();
SortedSet <int> states = new SortedSet <int>();
HashSet <InterpretTrace> contexts = new HashSet <InterpretTrace>(EqualityComparer <InterpretTrace> .Default);
#if false
HashSet <ContextFrame> existingUnique = new HashSet <ContextFrame>(existing.Select(i => i.StartContext), EqualityComparer <ContextFrame> .Default);
Contract.Assert(existingUnique.Count == existing.Count);
#endif
foreach (var context in existing)
{
states.Add(context.StartContext.State.Id);
StepBackward(contexts, states, context, symbol, symbolPosition, PreventContextType.None);
states.Clear();
}
bool success = false;
if (contexts.Count > 0)
{
_contexts.AddRange(contexts);
if (TrackBoundedContexts)
{
_boundedStartContexts.UnionWith(_contexts.Where(i => i.BoundedStart));
}
success = true;
}
else
{
_contexts.AddRange(existing);
}
long nfaUpdateTime = updateTimer.ElapsedMilliseconds;
#if DFA
/*
* Update the deterministic trace
*/
updateTimer.Restart();
DeterministicTransition deterministicTransition = _deterministicTrace.StartState.IncomingTransitions.SingleOrDefault(i => i.MatchSet.Contains(symbol));
if (deterministicTransition == null)
{
DeterministicState sourceState = new DeterministicState(contexts.Select(i => i.StartContext));
DeterministicState targetState = _deterministicTrace.StartState;
deterministicTransition = targetState.IncomingTransitions.SingleOrDefault(i => i.SourceState.Equals(sourceState));
if (deterministicTransition == null)
{
deterministicTransition = new DeterministicTransition(targetState);
sourceState.AddTransition(deterministicTransition);
}
deterministicTransition.MatchSet.Add(symbol);
}
IEnumerable <DeterministicTraceTransition> deterministicTransitions = Enumerable.Repeat(new DeterministicTraceTransition(deterministicTransition, symbol, symbolPosition, this), 1);
deterministicTransitions = deterministicTransitions.Concat(_deterministicTrace.Transitions);
_deterministicTrace = new DeterministicTrace(deterministicTransition.SourceState, _deterministicTrace.EndState, deterministicTransitions);
long dfaUpdateTime = updateTimer.ElapsedMilliseconds;
#endif
if (success)
{
_lookBehindPosition++;
}
if (!success)
{
_failedBackward = true;
}
return(success);
}
public DeterministicTransition([NotNull] DeterministicState targetState)
{
Requires.NotNull(targetState, nameof(targetState));
_targetState = targetState;
}
public DeterministicTransition(DeterministicState targetState)
{
Contract.Requires <ArgumentNullException>(targetState != null, "targetState");
_targetState = targetState;
}