102 lines
2.4 KiB
Go
102 lines
2.4 KiB
Go
// Copyright (c) 2015 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 it
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import (
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"bytes"
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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 LightStemmerName = "stemmer_it_light"
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type ItalianLightStemmerFilter struct {
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}
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func NewItalianLightStemmerFilterFilter() *ItalianLightStemmerFilter {
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return &ItalianLightStemmerFilter{}
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}
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func (s *ItalianLightStemmerFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
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for _, token := range input {
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runes := bytes.Runes(token.Term)
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runes = stem(runes)
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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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func stem(input []rune) []rune {
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inputLen := len(input)
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if inputLen < 6 {
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return input
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}
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for i := 0; i < inputLen; i++ {
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switch input[i] {
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case 'à', 'á', 'â', 'ä':
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input[i] = 'a'
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case 'ò', 'ó', 'ô', 'ö':
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input[i] = 'o'
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case 'è', 'é', 'ê', 'ë':
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input[i] = 'e'
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case 'ù', 'ú', 'û', 'ü':
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input[i] = 'u'
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case 'ì', 'í', 'î', 'ï':
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input[i] = 'i'
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}
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}
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switch input[inputLen-1] {
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case 'e':
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if input[inputLen-2] == 'i' || input[inputLen-2] == 'h' {
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return input[0 : inputLen-2]
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} else {
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return input[0 : inputLen-1]
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}
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case 'i':
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if input[inputLen-2] == 'h' || input[inputLen-2] == 'i' {
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return input[0 : inputLen-2]
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} else {
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return input[0 : inputLen-1]
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}
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case 'a':
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if input[inputLen-2] == 'i' {
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return input[0 : inputLen-2]
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} else {
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return input[0 : inputLen-1]
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}
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case 'o':
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if input[inputLen-2] == 'i' {
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return input[0 : inputLen-2]
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} else {
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return input[0 : inputLen-1]
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}
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}
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return input
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}
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func ItalianLightStemmerFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
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return NewItalianLightStemmerFilterFilter(), nil
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}
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func init() {
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registry.RegisterTokenFilter(LightStemmerName, ItalianLightStemmerFilterConstructor)
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}
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