func newSegmentTermsEnum(r *FieldReader) *SegmentTermsEnum {
ans := &SegmentTermsEnum{
FieldReader: r,
stack: make([]*segmentTermsEnumFrame, 0),
scratchReader: store.NewEmptyByteArrayDataInput(),
term: newBytesRef(),
arcs: make([]*fst.Arc, 1),
fstOutputs: fst.ByteSequenceOutputsSingleton(),
}
ans.TermsEnumImpl = newTermsEnumImpl(ans)
log.Printf("BTTR.init seg=%v", r.segment)
// Used to hold seek by TermState, or cached seek
ans.staticFrame = newFrame(ans, -1)
if r.index != nil {
ans.fstReader = r.index.BytesReader()
}
// Init w/ root block; don't use index since it may
// not (and need not) have been loaded
for i, _ := range ans.arcs {
ans.arcs[i] = &fst.Arc{}
}
ans.currentFrame = ans.staticFrame
var arc *fst.Arc
if r.index != nil {
arc = r.index.FirstArc(ans.arcs[0])
// Empty string prefix must have an output in the index!
if !arc.IsFinal() {
panic("assert fail")
}
}
ans.currentFrame = ans.staticFrame
ans.validIndexPrefix = 0
log.Printf("init frame state %v", ans.currentFrame.ord)
ans.printSeekState()
// ans.computeBlockStats()
return ans
}
func (e *SegmentTermsEnum) SeekExact(target []byte) (ok bool, err error) {
if e.index == nil {
panic("terms index was not loaded")
}
if cap(e.term.bytes) <= len(target) {
e.term.ensureSize(1 + len(target))
}
e.eof = false
log.Printf("BTTR.seekExact seg=%v target=%v:%v current=%v (exists?=%v) validIndexPrefix=%v",
e.segment, e.fieldInfo.Name, brToString(target), e.term, e.termExists, e.validIndexPrefix)
e.printSeekState()
var arc *fst.Arc
var targetUpto int
var output []byte
e.targetBeforeCurrentLength = e.currentFrame.ord
// if e.currentFrame != e.staticFrame {
if e.currentFrame.ord != e.staticFrame.ord {
// We are already seek'd; find the common
// prefix of new seek term vs current term and
// re-use the corresponding seek state. For
// example, if app first seeks to foobar, then
// seeks to foobaz, we can re-use the seek state
// for the first 5 bytes.
log.Printf(" re-use current seek state validIndexPrefix=%v", e.validIndexPrefix)
arc = e.arcs[0]
if !arc.IsFinal() {
panic("assert fail")
}
output = arc.Output.([]byte)
targetUpto = 0
lastFrame := e.stack[0]
if e.validIndexPrefix > e.term.length {
panic("assert fail")
}
targetLimit := len(target)
if e.validIndexPrefix < targetLimit {
targetLimit = e.validIndexPrefix
}
cmp := 0
// TODO: reverse vLong byte order for better FST
// prefix output sharing
noOutputs := e.fstOutputs.NoOutput()
// First compare up to valid seek frames:
for targetUpto < targetLimit {
cmp = int(e.term.bytes[targetUpto]) - int(target[targetUpto])
log.Printf(" cycle targetUpto=%v (vs limit=%v) cmp=%v (targetLabel=%c vs termLabel=%c) arc.output=%v output=%v",
targetUpto, targetLimit, cmp, target[targetUpto], e.term.bytes[targetUpto], arc.Output, output)
if cmp != 0 {
break
}
arc = e.arcs[1+targetUpto]
if arc.Label != int(target[targetUpto]) {
log.Printf("FAIL: arc.label=%c targetLabel=%c", arc.Label, target[targetUpto])
panic("assert fail")
}
if arc.Output != noOutputs {
output = e.fstOutputs.Add(output, arc.Output).([]byte)
}
if arc.IsFinal() {
lastFrame = e.stack[1+lastFrame.ord]
}
targetUpto++
}
if cmp == 0 {
targetUptoMid := targetUpto
// Second compare the rest of the term, but
// don't save arc/output/frame; we only do this
// to find out if the target term is before,
// equal or after the current term
targetLimit2 := len(target)
if e.term.length < targetLimit2 {
targetLimit2 = e.term.length
}
for targetUpto < targetLimit2 {
cmp = int(e.term.bytes[targetUpto]) - int(target[targetUpto])
log.Printf(" cycle2 targetUpto=%v (vs limit=%v) cmp=%v (targetLabel=%c vs termLabel=%c)",
targetUpto, targetLimit, cmp, target[targetUpto], e.term.bytes[targetUpto])
if cmp != 0 {
break
}
targetUpto++
}
if cmp == 0 {
cmp = e.term.length - len(target)
}
targetUpto = targetUptoMid
}
if cmp < 0 {
// Common case: target term is after current
// term, ie, app is seeking multiple terms
// in sorted order
log.Printf(" target is after current (shares prefixLen=%v); frame.ord=%v", targetUpto, lastFrame.ord)
e.currentFrame = lastFrame
} else if cmp > 0 {
// Uncommon case: target term
// is before current term; this means we can
// keep the currentFrame but we must rewind it
// (so we scan from the start)
e.targetBeforeCurrentLength = 0
log.Printf(" target is before current (shares prefixLen=%v); rewind frame ord=%v", targetUpto, lastFrame.ord)
e.currentFrame = lastFrame
e.currentFrame.rewind()
} else {
// Target is exactly the same as current term
if e.term.length != len(target) {
panic("assert fail")
}
if e.termExists {
log.Println(" target is same as current; return true")
return true, nil
} else {
log.Println(" target is same as current but term doesn't exist")
}
}
} else {
e.targetBeforeCurrentLength = -1
arc = e.index.FirstArc(e.arcs[0])
// Empty string prefix must have an output (block) in the index!
if !arc.IsFinal() || arc.Output == nil {
panic("assert fail")
}
log.Println(" no seek state; push root frame")
output = arc.Output.([]byte)
e.currentFrame = e.staticFrame
targetUpto = 0
e.currentFrame, err = e.pushFrame(arc, e.fstOutputs.Add(output, arc.NextFinalOutput).([]byte), 0)
if err != nil {
return false, err
}
}
log.Printf(" start index loop targetUpto=%v output=%v currentFrame.ord=%v targetBeforeCurrentLength=%v",
targetUpto, output, e.currentFrame.ord, e.targetBeforeCurrentLength)
for targetUpto < len(target) {
targetLabel := int(target[targetUpto])
nextArc, err := e.index.FindTargetArc(targetLabel, arc, e.getArc(1+targetUpto), e.fstReader)
if err != nil {
return false, err
}
if nextArc == nil {
// Index is exhausted
log.Printf(" index: index exhausted label=%c %x", targetLabel, targetLabel)
e.validIndexPrefix = e.currentFrame.prefix
e.currentFrame.scanToFloorFrame(target)
if !e.currentFrame.hasTerms {
e.termExists = false
e.term.bytes[targetUpto] = byte(targetLabel)
log.Printf(" FAST NOT_FOUND term=%v", e.term)
return false, nil
}
e.currentFrame.loadBlock()
status, err := e.currentFrame.scanToTerm(target, true)
if err != nil {
return false, err
}
if status == SEEK_STATUS_FOUND {
log.Printf(" return FOUND term=%v", e.term)
return true, nil
} else {
log.Printf(" got %v; return NOT_FOUND term=%v", status, e.term)
return false, nil
}
} else {
// Follow this arc
arc = nextArc
e.term.bytes[targetUpto] = byte(targetLabel)
if arc.Output == nil {
panic("assert fail")
}
noOutputs := e.fstOutputs.NoOutput()
if !fst.CompareFSTValue(arc.Output, noOutputs) {
output = e.fstOutputs.Add(output, arc.Output).([]byte)
}
log.Printf(" index: follow label=%x arc.output=%v arc.nfo=%v",
target[targetUpto], arc.Output, arc.NextFinalOutput)
targetUpto++
if arc.IsFinal() {
log.Println(" arc is final!")
e.currentFrame, err = e.pushFrame(arc, e.fstOutputs.Add(output, arc.NextFinalOutput).([]byte), targetUpto)
if err != nil {
return false, err
}
log.Printf(" curFrame.ord=%v hasTerms=%v", e.currentFrame.ord, e.currentFrame.hasTerms)
}
}
}
e.validIndexPrefix = e.currentFrame.prefix
e.currentFrame.scanToFloorFrame(target)
// Target term is entirely contained in the index:
if !e.currentFrame.hasTerms {
e.termExists = false
e.term.length = targetUpto
log.Printf(" FAST NOT_FOUND term=%v", e.term)
return false, nil
}
e.currentFrame.loadBlock()
status, err := e.currentFrame.scanToTerm(target, true)
if err != nil {
return false, err
}
if status == SEEK_STATUS_FOUND {
log.Printf(" return FOUND term=%v", e.term)
return true, nil
} else {
log.Printf(" got result %v; return NOT_FOUND term=%v", status, e.term)
return false, nil
}
}