Adding upstream version 2.5.1.

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

analysis/lang/es/light_stemmer_es.go

@@ -0,0 +1,78 @@
+//  Copyright (c) 2017 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 es
+
+import (
+	"bytes"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const LightStemmerName = "stemmer_es_light"
+
+type SpanishLightStemmerFilter struct {
+}
+
+func NewSpanishLightStemmerFilter() *SpanishLightStemmerFilter {
+	return &SpanishLightStemmerFilter{}
+}
+
+func (s *SpanishLightStemmerFilter) 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 {
+	l := len(input)
+	if l < 5 {
+		return input
+	}
+
+	switch input[l-1] {
+	case 'o', 'a', 'e':
+		return input[:l-1]
+	case 's':
+		if input[l-2] == 'e' && input[l-3] == 's' && input[l-4] == 'e' {
+			return input[:l-2]
+		}
+		if input[l-2] == 'e' && input[l-3] == 'c' {
+			input[l-3] = 'z'
+			return input[:l-2]
+		}
+		if input[l-2] == 'o' || input[l-2] == 'a' || input[l-2] == 'e' {
+			return input[:l-2]
+		}
+	}
+
+	return input
+}
+
+func SpanishLightStemmerFilterConstructor(config map[string]interface{},
+	cache *registry.Cache) (analysis.TokenFilter, error) {
+	return NewSpanishLightStemmerFilter(), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(LightStemmerName, SpanishLightStemmerFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}