Adding upstream version 2.5.1.

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

analysis/token/truncate/truncate.go

@@ -0,0 +1,62 @@
+//  Copyright (c) 2014 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 truncate
+
+import (
+	"fmt"
+	"unicode/utf8"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const Name = "truncate_token"
+
+type TruncateTokenFilter struct {
+	length int
+}
+
+func NewTruncateTokenFilter(length int) *TruncateTokenFilter {
+	return &TruncateTokenFilter{
+		length: length,
+	}
+}
+
+func (s *TruncateTokenFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	for _, token := range input {
+		wordLen := utf8.RuneCount(token.Term)
+		if wordLen > s.length {
+			token.Term = analysis.TruncateRunes(token.Term, wordLen-s.length)
+		}
+	}
+	return input
+}
+
+func TruncateTokenFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	lenVal, ok := config["length"].(float64)
+	if !ok {
+		return nil, fmt.Errorf("must specify length")
+	}
+	length := int(lenVal)
+
+	return NewTruncateTokenFilter(length), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(Name, TruncateTokenFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}

analysis/token/truncate/truncate_test.go

@@ -0,0 +1,79 @@
+//  Copyright (c) 2014 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 truncate
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+)
+
+func TestTruncateTokenFilter(t *testing.T) {
+
+	tests := []struct {
+		length int
+		input  analysis.TokenStream
+		output analysis.TokenStream
+	}{
+		{
+			length: 5,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("abcdefgh"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("abcde"),
+				},
+			},
+		},
+		{
+			length: 3,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("こんにちは世界"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("こんに"),
+				},
+			},
+		},
+		{
+			length: 10,
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("แยกคำภาษาไทยก็ทำได้นะจ้ะ"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("แยกคำภาษาไ"),
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		truncateTokenFilter := NewTruncateTokenFilter(test.length)
+		actual := truncateTokenFilter.Filter(test.input)
+		if !reflect.DeepEqual(actual, test.output) {
+			t.Errorf("expected %s, got %s", test.output[0].Term, actual[0].Term)
+		}
+	}
+}