Adding upstream version 2.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

analysis/lang/pt/light_stemmer_pt.go

@@ -0,0 +1,198 @@
+//  Copyright (c) 2015 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 pt
+
+import (
+	"bytes"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const LightStemmerName = "stemmer_pt_light"
+
+type PortugueseLightStemmerFilter struct {
+}
+
+func NewPortugueseLightStemmerFilter() *PortugueseLightStemmerFilter {
+	return &PortugueseLightStemmerFilter{}
+}
+
+func (s *PortugueseLightStemmerFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	for _, token := range input {
+		runes := bytes.Runes(token.Term)
+		runes = stem(runes)
+		token.Term = analysis.BuildTermFromRunes(runes)
+	}
+	return input
+}
+
+func stem(input []rune) []rune {
+
+	inputLen := len(input)
+
+	if inputLen < 4 {
+		return input
+	}
+
+	input = removeSuffix(input)
+	inputLen = len(input)
+
+	if inputLen > 3 && input[inputLen-1] == 'a' {
+		input = normFeminine(input)
+		inputLen = len(input)
+	}
+
+	if inputLen > 4 {
+		switch input[inputLen-1] {
+		case 'e', 'a', 'o':
+			input = input[0 : inputLen-1]
+			inputLen = len(input)
+		}
+	}
+
+	for i := 0; i < inputLen; i++ {
+		switch input[i] {
+		case 'à', 'á', 'â', 'ä', 'ã':
+			input[i] = 'a'
+		case 'ò', 'ó', 'ô', 'ö', 'õ':
+			input[i] = 'o'
+		case 'è', 'é', 'ê', 'ë':
+			input[i] = 'e'
+		case 'ù', 'ú', 'û', 'ü':
+			input[i] = 'u'
+		case 'ì', 'í', 'î', 'ï':
+			input[i] = 'i'
+		case 'ç':
+			input[i] = 'c'
+		}
+	}
+
+	return input
+}
+
+func removeSuffix(input []rune) []rune {
+
+	inputLen := len(input)
+
+	if inputLen > 4 && analysis.RunesEndsWith(input, "es") {
+		switch input[inputLen-3] {
+		case 'r', 's', 'l', 'z':
+			return input[0 : inputLen-2]
+		}
+	}
+
+	if inputLen > 3 && analysis.RunesEndsWith(input, "ns") {
+		input[inputLen-2] = 'm'
+		return input[0 : inputLen-1]
+	}
+
+	if inputLen > 4 && (analysis.RunesEndsWith(input, "eis") || analysis.RunesEndsWith(input, "éis")) {
+		input[inputLen-3] = 'e'
+		input[inputLen-2] = 'l'
+		return input[0 : inputLen-1]
+	}
+
+	if inputLen > 4 && analysis.RunesEndsWith(input, "ais") {
+		input[inputLen-2] = 'l'
+		return input[0 : inputLen-1]
+	}
+
+	if inputLen > 4 && analysis.RunesEndsWith(input, "óis") {
+		input[inputLen-3] = 'o'
+		input[inputLen-2] = 'l'
+		return input[0 : inputLen-1]
+	}
+
+	if inputLen > 4 && analysis.RunesEndsWith(input, "is") {
+		input[inputLen-1] = 'l'
+		return input
+	}
+
+	if inputLen > 3 &&
+		(analysis.RunesEndsWith(input, "ões") ||
+			analysis.RunesEndsWith(input, "ães")) {
+		input = input[0 : inputLen-1]
+		inputLen = len(input)
+		input[inputLen-2] = 'ã'
+		input[inputLen-1] = 'o'
+		return input
+	}
+
+	if inputLen > 6 && analysis.RunesEndsWith(input, "mente") {
+		return input[0 : inputLen-5]
+	}
+
+	if inputLen > 3 && input[inputLen-1] == 's' {
+		return input[0 : inputLen-1]
+	}
+	return input
+}
+
+func normFeminine(input []rune) []rune {
+	inputLen := len(input)
+
+	if inputLen > 7 &&
+		(analysis.RunesEndsWith(input, "inha") ||
+			analysis.RunesEndsWith(input, "iaca") ||
+			analysis.RunesEndsWith(input, "eira")) {
+		input[inputLen-1] = 'o'
+		return input
+	}
+
+	if inputLen > 6 {
+		if analysis.RunesEndsWith(input, "osa") ||
+			analysis.RunesEndsWith(input, "ica") ||
+			analysis.RunesEndsWith(input, "ida") ||
+			analysis.RunesEndsWith(input, "ada") ||
+			analysis.RunesEndsWith(input, "iva") ||
+			analysis.RunesEndsWith(input, "ama") {
+			input[inputLen-1] = 'o'
+			return input
+		}
+
+		if analysis.RunesEndsWith(input, "ona") {
+			input[inputLen-3] = 'ã'
+			input[inputLen-2] = 'o'
+			return input[0 : inputLen-1]
+		}
+
+		if analysis.RunesEndsWith(input, "ora") {
+			return input[0 : inputLen-1]
+		}
+
+		if analysis.RunesEndsWith(input, "esa") {
+			input[inputLen-3] = 'ê'
+			return input[0 : inputLen-1]
+		}
+
+		if analysis.RunesEndsWith(input, "na") {
+			input[inputLen-1] = 'o'
+			return input
+		}
+	}
+	return input
+}
+
+func PortugueseLightStemmerFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	return NewPortugueseLightStemmerFilter(), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(LightStemmerName, PortugueseLightStemmerFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}