Adding upstream version 2.5.1.

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

analysis/token/length/length.go

@@ -0,0 +1,80 @@
+//  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 length
+
+import (
+	"fmt"
+	"unicode/utf8"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const Name = "length"
+
+type LengthFilter struct {
+	min int
+	max int
+}
+
+func NewLengthFilter(min, max int) *LengthFilter {
+	return &LengthFilter{
+		min: min,
+		max: max,
+	}
+}
+
+func (f *LengthFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	rv := make(analysis.TokenStream, 0, len(input))
+
+	for _, token := range input {
+		wordLen := utf8.RuneCount(token.Term)
+		if f.min > 0 && f.min > wordLen {
+			continue
+		}
+		if f.max > 0 && f.max < wordLen {
+			continue
+		}
+		rv = append(rv, token)
+	}
+
+	return rv
+}
+
+func LengthFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	min := 0
+	max := 0
+
+	minVal, ok := config["min"].(float64)
+	if ok {
+		min = int(minVal)
+	}
+	maxVal, ok := config["max"].(float64)
+	if ok {
+		max = int(maxVal)
+	}
+	if min == max && max == 0 {
+		return nil, fmt.Errorf("either min or max must be non-zero")
+	}
+
+	return NewLengthFilter(min, max), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(Name, LengthFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}