Fixed endless loop bug in LevelDB interleaved spatial query. Simplified code.

common/coords.go

@@ -85,14 +85,22 @@ func EncodeStringToBytes(key int64) ([]byte, error) {
 	return []byte(strconv.FormatInt(key, 10)), nil
 }
 
-func EncodeToBigEndian(key int64) (enc []byte, err error) {
-	enc = make([]byte, 8)
+func ToBigEndian(key int64) []byte {
+	enc := make([]byte, 8)
 	binary.BigEndian.PutUint64(enc, uint64(key))
-	return
+	return enc
+}
+
+func EncodeToBigEndian(key int64) ([]byte, error) {
+	return ToBigEndian(key), nil
+}
+
+func FromBigEndian(key []byte) int64 {
+	return int64(binary.BigEndian.Uint64(key))
 }
 
 func DecodeFromBigEndian(key []byte) (int64, error) {
-	return int64(binary.BigEndian.Uint64(key)), nil
+	return FromBigEndian(key), nil
 }
 
 func CoordToInterleaved(c Coord) (result int64) {

leveldb.go

@@ -336,21 +336,13 @@ func (ldbs *LevelDBSession) interleavedSpatialQuery(first, second []byte, done c
 		zmin, zmax = order(zmin, zmax)
 		var (
 			cub        = common.Cuboid{P1: c1, P2: c2}
-			zcode      = zmin
 			err        error
 			encodedKey []byte
 		)
-	SEEK:
-		if encodedKey, err = common.EncodeToBigEndian(zcode); err != nil {
-			log.Printf("error encoding key: %s", err)
-			return
-		}
-		it.Seek(encodedKey)
+
+		it.Seek(common.ToBigEndian(zmin))
 		for it.Valid() {
-			if zcode, err = common.DecodeFromBigEndian(it.Key()); err != nil {
-				log.Printf("error decoding key: %s", err)
-				return
-			}
+			zcode := common.FromBigEndian(it.Key())
 
 			if zcode > zmax {
 				break
@@ -366,12 +358,10 @@ func (ldbs *LevelDBSession) interleavedSpatialQuery(first, second []byte, done c
 				case <-done:
 					return
 				}
+				it.Next()
 			} else {
-				zmin = common.NaiveBigMin(zmin, zmax, zcode)
-				goto SEEK
+				it.Seek(common.ToBigEndian(common.NaiveBigMin(zmin, zmax, zcode)))
 			}
-
-			it.Next()
 		}
 		if err = it.GetError(); err != nil {
 			log.Printf("error while iterating: %s", err)