043a3bfb7c
change cjk bigram analyzer to work with multi-rune terms add cjk width filter replaces full unicode normailzation these changes make the cjk analyzer behave more like elasticsearch they also remove the depenency on the whitespace analyzer which is now free to also behave more like lucene/es fixes #33
97 lines
3.1 KiB
Go
97 lines
3.1 KiB
Go
// Copyright (c) 2016 Couchbase, Inc.
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
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// except in compliance with the License. You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed under the
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// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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package cjk
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import (
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"bytes"
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"unicode/utf8"
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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 WidthName = "cjk_width"
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type CJKWidthFilter struct{}
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func NewCJKWidthFilter() *CJKWidthFilter {
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return &CJKWidthFilter{}
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}
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func (s *CJKWidthFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
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for _, token := range input {
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runeCount := utf8.RuneCount(token.Term)
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runes := bytes.Runes(token.Term)
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for i := 0; i < runeCount; i++ {
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ch := runes[i]
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if ch >= 0xFF01 && ch <= 0xFF5E {
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// fullwidth ASCII variants
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runes[i] -= 0xFEE0
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} else if ch >= 0xFF65 && ch <= 0xFF9F {
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// halfwidth Katakana variants
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if (ch == 0xFF9E || ch == 0xFF9F) && i > 0 && combine(runes, i, ch) {
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runes = analysis.DeleteRune(runes, i)
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i--
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runeCount = len(runes)
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} else {
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runes[i] = kanaNorm[ch-0xFF65]
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}
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}
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}
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token.Term = analysis.BuildTermFromRunes(runes)
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}
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return input
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}
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var kanaNorm = []rune{
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0x30fb, 0x30f2, 0x30a1, 0x30a3, 0x30a5, 0x30a7, 0x30a9, 0x30e3, 0x30e5,
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0x30e7, 0x30c3, 0x30fc, 0x30a2, 0x30a4, 0x30a6, 0x30a8, 0x30aa, 0x30ab,
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0x30ad, 0x30af, 0x30b1, 0x30b3, 0x30b5, 0x30b7, 0x30b9, 0x30bb, 0x30bd,
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0x30bf, 0x30c1, 0x30c4, 0x30c6, 0x30c8, 0x30ca, 0x30cb, 0x30cc, 0x30cd,
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0x30ce, 0x30cf, 0x30d2, 0x30d5, 0x30d8, 0x30db, 0x30de, 0x30df, 0x30e0,
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0x30e1, 0x30e2, 0x30e4, 0x30e6, 0x30e8, 0x30e9, 0x30ea, 0x30eb, 0x30ec,
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0x30ed, 0x30ef, 0x30f3, 0x3099, 0x309A,
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}
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var kanaCombineVoiced = []rune{
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78, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
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0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1,
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0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 8, 8, 8, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
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}
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var kanaCombineHalfVoiced = []rune{
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 2,
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0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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}
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func combine(text []rune, pos int, r rune) bool {
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prev := text[pos-1]
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if prev >= 0x30A6 && prev <= 0x30FD {
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if r == 0xFF9F {
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text[pos-1] += kanaCombineHalfVoiced[prev-0x30A6]
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} else {
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text[pos-1] += kanaCombineVoiced[prev-0x30A6]
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}
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return text[pos-1] != prev
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}
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return false
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}
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func CJKWidthFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
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return NewCJKWidthFilter(), nil
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}
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func init() {
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registry.RegisterTokenFilter(WidthName, CJKWidthFilterConstructor)
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}
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