196 lines
4.5 KiB
Go
196 lines
4.5 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 pt
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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_pt_light"
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type PortugueseLightStemmerFilter struct {
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}
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func NewPortugueseLightStemmerFilter() *PortugueseLightStemmerFilter {
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return &PortugueseLightStemmerFilter{}
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}
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func (s *PortugueseLightStemmerFilter) 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 < 4 {
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return input
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}
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input = removeSuffix(input)
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inputLen = len(input)
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if inputLen > 3 && input[inputLen-1] == 'a' {
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input = normFeminine(input)
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inputLen = len(input)
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}
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if inputLen > 4 {
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switch input[inputLen-1] {
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case 'e', 'a', 'o':
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input = input[0 : inputLen-1]
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inputLen = len(input)
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}
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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', 'ã':
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input[i] = 'a'
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case 'ò', 'ó', 'ô', 'ö', 'õ':
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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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case 'ç':
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input[i] = 'c'
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}
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}
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return input
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}
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func removeSuffix(input []rune) []rune {
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inputLen := len(input)
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if inputLen > 4 && analysis.RunesEndsWith(input, "es") {
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switch input[inputLen-3] {
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case 'r', 's', 'l', 'z':
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return input[0 : inputLen-2]
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}
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}
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if inputLen > 3 && analysis.RunesEndsWith(input, "ns") {
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input[inputLen-2] = 'm'
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return input[0 : inputLen-1]
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}
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if inputLen > 4 && (analysis.RunesEndsWith(input, "eis") || analysis.RunesEndsWith(input, "éis")) {
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input[inputLen-3] = 'e'
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input[inputLen-2] = 'l'
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return input[0 : inputLen-1]
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}
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if inputLen > 4 && analysis.RunesEndsWith(input, "ais") {
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input[inputLen-2] = 'l'
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return input[0 : inputLen-1]
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}
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if inputLen > 4 && analysis.RunesEndsWith(input, "óis") {
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input[inputLen-3] = 'o'
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input[inputLen-2] = 'l'
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return input[0 : inputLen-1]
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}
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if inputLen > 4 && analysis.RunesEndsWith(input, "is") {
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input[inputLen-1] = 'l'
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return input
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}
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if inputLen > 3 &&
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(analysis.RunesEndsWith(input, "ões") ||
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analysis.RunesEndsWith(input, "ães")) {
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input = input[0 : inputLen-1]
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inputLen = len(input)
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input[inputLen-2] = 'ã'
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input[inputLen-1] = 'o'
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return input
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}
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if inputLen > 6 && analysis.RunesEndsWith(input, "mente") {
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return input[0 : inputLen-5]
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}
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if inputLen > 3 && input[inputLen-1] == 's' {
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return input[0 : inputLen-1]
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}
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return input
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}
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func normFeminine(input []rune) []rune {
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inputLen := len(input)
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if inputLen > 7 &&
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(analysis.RunesEndsWith(input, "inha") ||
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analysis.RunesEndsWith(input, "iaca") ||
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analysis.RunesEndsWith(input, "eira")) {
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input[inputLen-1] = 'o'
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return input
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}
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if inputLen > 6 {
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if analysis.RunesEndsWith(input, "osa") ||
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analysis.RunesEndsWith(input, "ica") ||
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analysis.RunesEndsWith(input, "ida") ||
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analysis.RunesEndsWith(input, "ada") ||
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analysis.RunesEndsWith(input, "iva") ||
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analysis.RunesEndsWith(input, "ama") {
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input[inputLen-1] = 'o'
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return input
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}
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if analysis.RunesEndsWith(input, "ona") {
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input[inputLen-3] = 'ã'
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input[inputLen-2] = 'o'
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return input[0 : inputLen-1]
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}
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if analysis.RunesEndsWith(input, "ora") {
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return input[0 : inputLen-1]
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}
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if analysis.RunesEndsWith(input, "esa") {
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input[inputLen-3] = 'ê'
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return input[0 : inputLen-1]
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}
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if analysis.RunesEndsWith(input, "na") {
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input[inputLen-1] = 'o'
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return input
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}
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}
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return input
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}
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func PortugueseLightStemmerFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
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return NewPortugueseLightStemmerFilter(), nil
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}
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func init() {
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registry.RegisterTokenFilter(LightStemmerName, PortugueseLightStemmerFilterConstructor)
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}
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