gitroast/vendor/github.com/blevesearch/bleve/analysis/tokenizer/unicode/unicode.go

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2017-01-25 02:43:02 +00:00
// 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.
package unicode
import (
"github.com/blevesearch/segment"
"github.com/blevesearch/bleve/analysis"
"github.com/blevesearch/bleve/registry"
)
const Name = "unicode"
type UnicodeTokenizer struct {
}
func NewUnicodeTokenizer() *UnicodeTokenizer {
return &UnicodeTokenizer{}
}
func (rt *UnicodeTokenizer) Tokenize(input []byte) analysis.TokenStream {
rvx := make([]analysis.TokenStream, 0, 10) // When rv gets full, append to rvx.
rv := make(analysis.TokenStream, 0, 1)
ta := []analysis.Token(nil)
taNext := 0
segmenter := segment.NewWordSegmenterDirect(input)
start := 0
pos := 1
guessRemaining := func(end int) int {
avgSegmentLen := end / (len(rv) + 1)
if avgSegmentLen < 1 {
avgSegmentLen = 1
}
remainingLen := len(input) - end
return remainingLen / avgSegmentLen
}
for segmenter.Segment() {
segmentBytes := segmenter.Bytes()
end := start + len(segmentBytes)
if segmenter.Type() != segment.None {
if taNext >= len(ta) {
remainingSegments := guessRemaining(end)
if remainingSegments > 1000 {
remainingSegments = 1000
}
if remainingSegments < 1 {
remainingSegments = 1
}
ta = make([]analysis.Token, remainingSegments)
taNext = 0
}
token := &ta[taNext]
taNext++
token.Term = segmentBytes
token.Start = start
token.End = end
token.Position = pos
token.Type = convertType(segmenter.Type())
if len(rv) >= cap(rv) { // When rv is full, save it into rvx.
rvx = append(rvx, rv)
rvCap := cap(rv) * 2
if rvCap > 256 {
rvCap = 256
}
rv = make(analysis.TokenStream, 0, rvCap) // Next rv cap is bigger.
}
rv = append(rv, token)
pos++
}
start = end
}
if len(rvx) > 0 {
n := len(rv)
for _, r := range rvx {
n += len(r)
}
rall := make(analysis.TokenStream, 0, n)
for _, r := range rvx {
rall = append(rall, r...)
}
return append(rall, rv...)
}
return rv
}
func UnicodeTokenizerConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.Tokenizer, error) {
return NewUnicodeTokenizer(), nil
}
func init() {
registry.RegisterTokenizer(Name, UnicodeTokenizerConstructor)
}
func convertType(segmentWordType int) analysis.TokenType {
switch segmentWordType {
case segment.Ideo:
return analysis.Ideographic
case segment.Kana:
return analysis.Ideographic
case segment.Number:
return analysis.Numeric
}
return analysis.AlphaNumeric
}