2014-07-30 18:30:38 +02:00
|
|
|
// Copyright (c) 2014 Couchbase, Inc.
|
|
|
|
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
|
|
|
|
// except in compliance with the License. You may obtain a copy of the License at
|
|
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
// Unless required by applicable law or agreed to in writing, software distributed under the
|
|
|
|
// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
|
|
|
|
// either express or implied. See the License for the specific language governing permissions
|
|
|
|
// and limitations under the License.
|
2014-06-26 17:43:13 +02:00
|
|
|
|
2014-09-01 17:15:38 +02:00
|
|
|
package simple
|
2014-06-26 17:43:13 +02:00
|
|
|
|
2014-09-01 17:15:38 +02:00
|
|
|
import (
|
|
|
|
"github.com/blevesearch/bleve/registry"
|
|
|
|
"github.com/blevesearch/bleve/search/highlight"
|
|
|
|
)
|
|
|
|
|
|
|
|
const Name = "simple"
|
|
|
|
|
|
|
|
const defaultFragmentSize = 200
|
2014-06-26 17:43:13 +02:00
|
|
|
|
2014-09-04 01:16:46 +02:00
|
|
|
type Fragmenter struct {
|
2014-06-26 17:43:13 +02:00
|
|
|
fragmentSize int
|
|
|
|
}
|
|
|
|
|
2014-09-04 01:16:46 +02:00
|
|
|
func NewFragmenter(fragmentSize int) *Fragmenter {
|
|
|
|
return &Fragmenter{
|
2014-06-26 17:43:13 +02:00
|
|
|
fragmentSize: fragmentSize,
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2014-09-04 01:16:46 +02:00
|
|
|
func (s *Fragmenter) Fragment(orig []byte, ot highlight.TermLocations) []*highlight.Fragment {
|
2014-09-01 17:15:38 +02:00
|
|
|
rv := make([]*highlight.Fragment, 0)
|
2014-06-26 17:43:13 +02:00
|
|
|
|
|
|
|
maxbegin := 0
|
|
|
|
for currTermIndex, termLocation := range ot {
|
|
|
|
// start with with this
|
|
|
|
// it should be the highest scoring fragment with this term first
|
|
|
|
start := termLocation.Start
|
|
|
|
end := start + s.fragmentSize
|
|
|
|
if end > len(orig) {
|
|
|
|
end = len(orig)
|
|
|
|
// we hit end, so push back as far as we can without crossing maxbegin
|
|
|
|
extra := s.fragmentSize - (end - start)
|
|
|
|
if start-extra >= maxbegin {
|
|
|
|
start -= extra
|
|
|
|
} else {
|
|
|
|
start = maxbegin
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// however, we'd rather have the tokens centered more in the frag
|
|
|
|
// lets try to do that as best we can, without affecting the score
|
|
|
|
// find the end of the last term in this fragment
|
|
|
|
minend := end
|
|
|
|
for _, innerTermLocation := range ot[currTermIndex:] {
|
|
|
|
if innerTermLocation.End > end {
|
|
|
|
break
|
|
|
|
}
|
|
|
|
minend = innerTermLocation.End
|
|
|
|
}
|
|
|
|
|
|
|
|
// find the smaller of the two rooms to move
|
|
|
|
roomToMove := end - minend
|
|
|
|
if start-maxbegin < roomToMove {
|
|
|
|
roomToMove = start - maxbegin
|
|
|
|
}
|
|
|
|
|
|
|
|
offset := roomToMove / 2
|
2014-09-01 17:15:38 +02:00
|
|
|
rv = append(rv, &highlight.Fragment{Orig: orig, Start: start - offset, End: end - offset})
|
2014-06-26 17:43:13 +02:00
|
|
|
// set maxbegin to the end of the current term location
|
|
|
|
// so that next one won't back up to include it
|
|
|
|
maxbegin = termLocation.End
|
|
|
|
|
|
|
|
}
|
2014-08-28 20:46:30 +02:00
|
|
|
if len(ot) == 0 {
|
|
|
|
// if there were no terms to highlight
|
|
|
|
// produce a single fragment from the beginning
|
|
|
|
start := 0
|
|
|
|
end := start + s.fragmentSize
|
|
|
|
if end > len(orig) {
|
|
|
|
end = len(orig)
|
|
|
|
}
|
2014-09-01 17:15:38 +02:00
|
|
|
rv = append(rv, &highlight.Fragment{Orig: orig, Start: start, End: end})
|
2014-08-28 20:46:30 +02:00
|
|
|
}
|
2014-06-26 17:43:13 +02:00
|
|
|
|
|
|
|
return rv
|
|
|
|
}
|
2014-09-01 17:15:38 +02:00
|
|
|
|
|
|
|
func Constructor(config map[string]interface{}, cache *registry.Cache) (highlight.Fragmenter, error) {
|
|
|
|
size := defaultFragmentSize
|
|
|
|
sizeVal, ok := config["size"].(float64)
|
|
|
|
if ok {
|
|
|
|
size = int(sizeVal)
|
|
|
|
}
|
2014-09-04 01:16:46 +02:00
|
|
|
return NewFragmenter(size), nil
|
2014-09-01 17:15:38 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
func init() {
|
|
|
|
registry.RegisterFragmenter(Name, Constructor)
|
|
|
|
}
|