Adding upstream version 2.5.1.

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

analysis/lang/pl/stemmer_pl.go

@@ -0,0 +1,58 @@
+//  Copyright (c) 2018 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 pl
+
+import (
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/analysis/lang/pl/stempel"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const SnowballStemmerName = "stemmer_pl"
+
+type PolishStemmerFilter struct {
+	trie stempel.Trie
+}
+
+func NewPolishStemmerFilter() (*PolishStemmerFilter, error) {
+	trie, err := stempel.LoadTrie()
+	if err != nil {
+		return nil, err
+	}
+	return &PolishStemmerFilter{
+		trie: trie,
+	}, nil
+}
+
+func (s *PolishStemmerFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	for _, token := range input {
+		buff := []rune(string(token.Term))
+		diff := s.trie.GetLastOnPath(buff)
+		buff = stempel.Diff(buff, diff)
+		token.Term = []byte(string(buff))
+	}
+	return input
+}
+
+func PolishStemmerFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	return NewPolishStemmerFilter()
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(SnowballStemmerName, PolishStemmerFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}