0
0
bleve/search/fragmenter_simple.go
Marty Schoch 2968d3538a major refactor, apologies for the large commit
removed analyzers (these are now built as needed through config)
removed html chacter filter (now built as needed through config)
added missing license header
changed constructor signature of filters that cannot return errors
filter constructors that can have errors, now have Must variant which panics
change cdl2 tokenizer into filter (should only see lower-case input)
new top level index api, closes #5
refactored index tests to not rely directly on analyzers
moved query objects to top-level
new top level search api, closes #12
top score collector allows skipping results
index mapping supports _all by default, closes #3 and closes #6
index mapping supports disabled sections, closes #7
new http sub package with reusable http.Handler's, closes #22
2014-07-30 12:30:38 -04:00

77 lines
2.2 KiB
Go

// 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.
package search
import ()
const DEFAULT_FRAGMENT_SIZE = 100
type SimpleFragmenter struct {
fragmentSize int
}
func NewSimpleFragmenter() *SimpleFragmenter {
return &SimpleFragmenter{
fragmentSize: DEFAULT_FRAGMENT_SIZE,
}
}
func NewSimpleFragmenterWithSize(fragmentSize int) *SimpleFragmenter {
return &SimpleFragmenter{
fragmentSize: fragmentSize,
}
}
func (s *SimpleFragmenter) Fragment(orig []byte, ot termLocations) []*Fragment {
rv := make([]*Fragment, 0)
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
rv = append(rv, &Fragment{orig: orig, start: start - offset, end: end - offset})
// set maxbegin to the end of the current term location
// so that next one won't back up to include it
maxbegin = termLocation.End
}
return rv
}