New norm disk format for zap

build.go

@@ -22,7 +22,7 @@ import (
 	"github.com/couchbase/vellum"
 )
 
-const Version uint32 = 14
+const Version uint32 = 15
 
 const Type string = "zap"
 

merge.go

@@ -487,7 +487,12 @@ func mergeTermFreqNormLocs(fieldsMap map[string]uint16, term []byte, postItr *Po
 		newRoaring.Add(uint32(hitNewDocNum))
 
 		nextFreq := next.Frequency()
-		nextNorm := uint64(math.Float32bits(float32(next.Norm())))
+		var nextNorm uint64
+		if pi, ok := next.(*Posting); ok {
+			nextNorm = pi.NormUint64()
+		} else {
+			return 0, 0, 0, nil, fmt.Errorf("unexpected posting type %T", next)
+		}
 
 		locs := next.Locations()
 

new.go

@@ -456,7 +456,7 @@ func (s *interim) processDocument(docNum uint64,
 	// now that it's been rolled up into fieldTFs, walk that
 	for fieldID, tfs := range fieldTFs {
 		dict := s.Dicts[fieldID]
-		norm := float32(1.0 / math.Sqrt(float64(fieldLens[fieldID])))
+		norm := math.Float32frombits(uint32(fieldLens[fieldID]))
 
 		for term, tf := range tfs {
 			pid := dict[term] - 1

posting.go

@@ -92,7 +92,7 @@ func under32Bits(x uint64) bool {
 
 const DocNum1HitFinished = math.MaxUint64
 
-var NormBits1Hit = uint64(math.Float32bits(float32(1)))
+var NormBits1Hit = uint64(1)
 
 // PostingsList is an in-memory representation of a postings list
 type PostingsList struct {
@@ -748,14 +748,19 @@ func (p *Posting) Frequency() uint64 {
 
 // Norm returns the normalization factor for this posting
 func (p *Posting) Norm() float64 {
-	return float64(p.norm)
+	return float64(float32(1.0 / math.Sqrt(float64(math.Float32bits(p.norm)))))
 }
 
 // Locations returns the location information for each occurrence
 func (p *Posting) Locations() []segment.Location {
 	return p.locs
 }
 
+// NormUint64 returns the norm value as uint64
+func (p *Posting) NormUint64() uint64 {
+	return uint64(math.Float32bits(p.norm))
+}
+
 // Location represents the location of a single occurrence
 type Location struct {
 	field string