// Uncomment for debugging:
/*
* public static <T> void dotToFile(FST<T> fst, String filePath) throws IOException {
* Writer w = new OutputStreamWriter(new FileOutputStream(filePath));
* toDot(fst, w, true, true);
* w.Dispose();
* }
*/
/// <summary>
/// Reads the first arc greater or equal that the given label into the provided
/// arc in place and returns it iff found, otherwise return <c>null</c>.
/// </summary>
/// <param name="label"> the label to ceil on </param>
/// <param name="fst"> the fst to operate on </param>
/// <param name="follow"> the arc to follow reading the label from </param>
/// <param name="arc"> the arc to read into in place </param>
/// <param name="in"> the fst's <see cref="FST.BytesReader"/> </param>
public static FST.Arc <T> ReadCeilArc <T>(int label, FST <T> fst, FST.Arc <T> follow, FST.Arc <T> arc, FST.BytesReader @in)
{
// TODO maybe this is a useful in the FST class - we could simplify some other code like FSTEnum?
if (label == FST.END_LABEL)
{
if (follow.IsFinal)
{
if (follow.Target <= 0)
{
arc.Flags = (sbyte)FST.BIT_LAST_ARC;
}
else
{
arc.Flags = 0;
// NOTE: nextArc is a node (not an address!) in this case:
arc.NextArc = follow.Target;
arc.Node = follow.Target;
}
arc.Output = follow.NextFinalOutput;
arc.Label = FST.END_LABEL;
return(arc);
}
else
{
return(null);
}
}
if (!FST <T> .TargetHasArcs(follow))
{
return(null);
}
fst.ReadFirstTargetArc(follow, arc, @in);
if (arc.BytesPerArc != 0 && arc.Label != FST.END_LABEL)
{
// Arcs are fixed array -- use binary search to find
// the target.
int low = arc.ArcIdx;
int high = arc.NumArcs - 1;
int mid = 0;
// System.out.println("do arc array low=" + low + " high=" + high +
// " targetLabel=" + targetLabel);
while (low <= high)
{
mid = (int)((uint)(low + high) >> 1);
@in.Position = arc.PosArcsStart;
@in.SkipBytes(arc.BytesPerArc * mid + 1);
int midLabel = fst.ReadLabel(@in);
int cmp = midLabel - label;
// System.out.println(" cycle low=" + low + " high=" + high + " mid=" +
// mid + " midLabel=" + midLabel + " cmp=" + cmp);
if (cmp < 0)
{
low = mid + 1;
}
else if (cmp > 0)
{
high = mid - 1;
}
else
{
arc.ArcIdx = mid - 1;
return(fst.ReadNextRealArc(arc, @in));
}
}
if (low == arc.NumArcs)
{
// DEAD END!
return(null);
}
arc.ArcIdx = (low > high ? high : low);
return(fst.ReadNextRealArc(arc, @in));
}
// Linear scan
fst.ReadFirstRealTargetArc(follow.Target, arc, @in);
while (true)
{
// System.out.println(" non-bs cycle");
// TODO: we should fix this code to not have to create
// object for the output of every arc we scan... only
// for the matching arc, if found
if (arc.Label >= label)
{
// System.out.println(" found!");
return(arc);
}
else if (arc.IsLast)
{
return(null);
}
else
{
fst.ReadNextRealArc(arc, @in);
}
}
}
/// <summary>
/// Expert: like <see cref="Util.GetByOutput(FST{long?}, long)"/> except reusing
/// <see cref="FST.BytesReader"/>, initial and scratch Arc, and result.
/// </summary>
public static Int32sRef GetByOutput(FST <long?> fst, long targetOutput, FST.BytesReader @in, FST.Arc <long?> arc, FST.Arc <long?> scratchArc, Int32sRef result)
{
long output = arc.Output.Value;
int upto = 0;
//System.out.println("reverseLookup output=" + targetOutput);
while (true)
{
//System.out.println("loop: output=" + output + " upto=" + upto + " arc=" + arc);
if (arc.IsFinal)
{
long finalOutput = output + arc.NextFinalOutput.Value;
//System.out.println(" isFinal finalOutput=" + finalOutput);
if (finalOutput == targetOutput)
{
result.Length = upto;
//System.out.println(" found!");
return(result);
}
else if (finalOutput > targetOutput)
{
//System.out.println(" not found!");
return(null);
}
}
if (FST <long?> .TargetHasArcs(arc))
{
//System.out.println(" targetHasArcs");
if (result.Int32s.Length == upto)
{
result.Grow(1 + upto);
}
fst.ReadFirstRealTargetArc(arc.Target, arc, @in);
if (arc.BytesPerArc != 0)
{
int low = 0;
int high = arc.NumArcs - 1;
int mid = 0;
//System.out.println("bsearch: numArcs=" + arc.numArcs + " target=" + targetOutput + " output=" + output);
bool exact = false;
while (low <= high)
{
mid = (int)((uint)(low + high) >> 1);
@in.Position = arc.PosArcsStart;
@in.SkipBytes(arc.BytesPerArc * mid);
var flags = (sbyte)@in.ReadByte();
fst.ReadLabel(@in);
long minArcOutput;
if ((flags & FST.BIT_ARC_HAS_OUTPUT) != 0)
{
long arcOutput = fst.Outputs.Read(@in).Value;
minArcOutput = output + arcOutput;
}
else
{
minArcOutput = output;
}
if (minArcOutput == targetOutput)
{
exact = true;
break;
}
else if (minArcOutput < targetOutput)
{
low = mid + 1;
}
else
{
high = mid - 1;
}
}
if (high == -1)
{
return(null);
}
else if (exact)
{
arc.ArcIdx = mid - 1;
}
else
{
arc.ArcIdx = low - 2;
}
fst.ReadNextRealArc(arc, @in);
result.Int32s[upto++] = arc.Label;
output += arc.Output.Value;
}
else
{
FST.Arc <long?> prevArc = null;
while (true)
{
//System.out.println(" cycle label=" + arc.label + " output=" + arc.output);
// this is the min output we'd hit if we follow
// this arc:
long minArcOutput = output + arc.Output.Value;
if (minArcOutput == targetOutput)
{
// Recurse on this arc:
//System.out.println(" match! break");
output = minArcOutput;
result.Int32s[upto++] = arc.Label;
break;
}
else if (minArcOutput > targetOutput)
{
if (prevArc == null)
{
// Output doesn't exist
return(null);
}
else
{
// Recurse on previous arc:
arc.CopyFrom(prevArc);
result.Int32s[upto++] = arc.Label;
output += arc.Output.Value;
//System.out.println(" recurse prev label=" + (char) arc.label + " output=" + output);
break;
}
}
else if (arc.IsLast)
{
// Recurse on this arc:
output = minArcOutput;
//System.out.println(" recurse last label=" + (char) arc.label + " output=" + output);
result.Int32s[upto++] = arc.Label;
break;
}
else
{
// Read next arc in this node:
prevArc = scratchArc;
prevArc.CopyFrom(arc);
//System.out.println(" after copy label=" + (char) prevArc.label + " vs " + (char) arc.label);
fst.ReadNextRealArc(arc, @in);
}
}
}
}
else
{
//System.out.println(" no target arcs; not found!");
return(null);
}
}
}
// TODO: should we return a status here (SEEK_FOUND / SEEK_NOT_FOUND /
// SEEK_END)? saves the eq check above?
/// <summary>
/// Seeks to smallest term that's >= target. </summary>
protected virtual void DoSeekCeil()
{
//System.out.println(" advance len=" + target.length + " curlen=" + current.length);
// TODO: possibly caller could/should provide common
// prefix length? ie this work may be redundant if
// caller is in fact intersecting against its own
// automaton
//System.out.println("FE.seekCeil upto=" + upto);
// Save time by starting at the end of the shared prefix
// b/w our current term & the target:
RewindPrefix();
//System.out.println(" after rewind upto=" + upto);
FST.Arc <T> arc = GetArc(m_upto);
int targetLabel = TargetLabel;
//System.out.println(" init targetLabel=" + targetLabel);
// Now scan forward, matching the new suffix of the target
while (true)
{
//System.out.println(" cycle upto=" + upto + " arc.label=" + arc.label + " (" + (char) arc.label + ") vs targetLabel=" + targetLabel);
if (arc.BytesPerArc != 0 && arc.Label != -1)
{
// Arcs are fixed array -- use binary search to find
// the target.
FST.BytesReader @in = m_fst.GetBytesReader();
int low = arc.ArcIdx;
int high = arc.NumArcs - 1;
int mid = 0;
//System.out.println("do arc array low=" + low + " high=" + high + " targetLabel=" + targetLabel);
bool found = false;
while (low <= high)
{
mid = (int)((uint)(low + high) >> 1);
@in.Position = arc.PosArcsStart;
@in.SkipBytes(arc.BytesPerArc * mid + 1);
int midLabel = m_fst.ReadLabel(@in);
int cmp = midLabel - targetLabel;
//System.out.println(" cycle low=" + low + " high=" + high + " mid=" + mid + " midLabel=" + midLabel + " cmp=" + cmp);
if (cmp < 0)
{
low = mid + 1;
}
else if (cmp > 0)
{
high = mid - 1;
}
else
{
found = true;
break;
}
}
// NOTE: this code is dup'd w/ the code below (in
// the outer else clause):
if (found)
{
// Match
arc.ArcIdx = mid - 1;
m_fst.ReadNextRealArc(arc, @in);
if (Debugging.AssertsEnabled)
{
Debugging.Assert(arc.ArcIdx == mid);
Debugging.Assert(arc.Label == targetLabel, "arc.label={0} vs targetLabel={1} mid={2}", arc.Label, targetLabel, mid);
}
m_output[m_upto] = m_fst.Outputs.Add(m_output[m_upto - 1], arc.Output);
if (targetLabel == FST.END_LABEL)
{
return;
}
CurrentLabel = arc.Label;
Incr();
arc = m_fst.ReadFirstTargetArc(arc, GetArc(m_upto), m_fstReader);
targetLabel = TargetLabel;
continue;
}
else if (low == arc.NumArcs)
{
// Dead end
arc.ArcIdx = arc.NumArcs - 2;
m_fst.ReadNextRealArc(arc, @in);
if (Debugging.AssertsEnabled)
{
Debugging.Assert(arc.IsLast);
}
// Dead end (target is after the last arc);
// rollback to last fork then push
m_upto--;
while (true)
{
if (m_upto == 0)
{
return;
}
FST.Arc <T> prevArc = GetArc(m_upto);
//System.out.println(" rollback upto=" + upto + " arc.label=" + prevArc.label + " isLast?=" + prevArc.isLast());
if (!prevArc.IsLast)
{
m_fst.ReadNextArc(prevArc, m_fstReader);
PushFirst();
return;
}
m_upto--;
}
}
else
{
arc.ArcIdx = (low > high ? low : high) - 1;
m_fst.ReadNextRealArc(arc, @in);
if (Debugging.AssertsEnabled)
{
Debugging.Assert(arc.Label > targetLabel);
}
PushFirst();
return;
}
}
else
{
// Arcs are not array'd -- must do linear scan:
if (arc.Label == targetLabel)
{
// recurse
m_output[m_upto] = m_fst.Outputs.Add(m_output[m_upto - 1], arc.Output);
if (targetLabel == FST.END_LABEL)
{
return;
}
CurrentLabel = arc.Label;
Incr();
arc = m_fst.ReadFirstTargetArc(arc, GetArc(m_upto), m_fstReader);
targetLabel = TargetLabel;
}
else if (arc.Label > targetLabel)
{
PushFirst();
return;
}
else if (arc.IsLast)
{
// Dead end (target is after the last arc);
// rollback to last fork then push
m_upto--;
while (true)
{
if (m_upto == 0)
{
return;
}
FST.Arc <T> prevArc = GetArc(m_upto);
//System.out.println(" rollback upto=" + upto + " arc.label=" + prevArc.label + " isLast?=" + prevArc.isLast());
if (!prevArc.IsLast)
{
m_fst.ReadNextArc(prevArc, m_fstReader);
PushFirst();
return;
}
m_upto--;
}
}
else
{
// keep scanning
//System.out.println(" next scan");
m_fst.ReadNextArc(arc, m_fstReader);
}
}
}
}
