132 lines
3.0 KiB
Go
132 lines
3.0 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package unicode
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import (
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"github.com/blevesearch/segment"
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"github.com/blevesearch/bleve/analysis"
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"github.com/blevesearch/bleve/registry"
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)
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const Name = "unicode"
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type UnicodeTokenizer struct {
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}
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func NewUnicodeTokenizer() *UnicodeTokenizer {
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return &UnicodeTokenizer{}
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}
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func (rt *UnicodeTokenizer) Tokenize(input []byte) analysis.TokenStream {
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rvx := make([]analysis.TokenStream, 0, 10) // When rv gets full, append to rvx.
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rv := make(analysis.TokenStream, 0, 1)
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ta := []analysis.Token(nil)
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taNext := 0
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segmenter := segment.NewWordSegmenterDirect(input)
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start := 0
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pos := 1
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guessRemaining := func(end int) int {
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avgSegmentLen := end / (len(rv) + 1)
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if avgSegmentLen < 1 {
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avgSegmentLen = 1
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}
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remainingLen := len(input) - end
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return remainingLen / avgSegmentLen
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}
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for segmenter.Segment() {
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segmentBytes := segmenter.Bytes()
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end := start + len(segmentBytes)
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if segmenter.Type() != segment.None {
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if taNext >= len(ta) {
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remainingSegments := guessRemaining(end)
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if remainingSegments > 1000 {
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remainingSegments = 1000
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}
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if remainingSegments < 1 {
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remainingSegments = 1
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}
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ta = make([]analysis.Token, remainingSegments)
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taNext = 0
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}
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token := &ta[taNext]
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taNext++
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token.Term = segmentBytes
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token.Start = start
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token.End = end
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token.Position = pos
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token.Type = convertType(segmenter.Type())
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if len(rv) >= cap(rv) { // When rv is full, save it into rvx.
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rvx = append(rvx, rv)
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rvCap := cap(rv) * 2
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if rvCap > 256 {
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rvCap = 256
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}
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rv = make(analysis.TokenStream, 0, rvCap) // Next rv cap is bigger.
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}
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rv = append(rv, token)
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pos++
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}
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start = end
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}
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if len(rvx) > 0 {
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n := len(rv)
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for _, r := range rvx {
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n += len(r)
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}
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rall := make(analysis.TokenStream, 0, n)
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for _, r := range rvx {
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rall = append(rall, r...)
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}
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return append(rall, rv...)
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}
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return rv
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}
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func UnicodeTokenizerConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.Tokenizer, error) {
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return NewUnicodeTokenizer(), nil
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}
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func init() {
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registry.RegisterTokenizer(Name, UnicodeTokenizerConstructor)
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}
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func convertType(segmentWordType int) analysis.TokenType {
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switch segmentWordType {
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case segment.Ideo:
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return analysis.Ideographic
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case segment.Kana:
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return analysis.Ideographic
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case segment.Number:
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return analysis.Numeric
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}
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return analysis.AlphaNumeric
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}
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