Adding upstream version 2.5.1.

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

analysis/lang/fa/persian_normalize.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 fa
+
+import (
+	"bytes"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const NormalizeName = "normalize_fa"
+
+const (
+	Yeh        = '\u064A'
+	FarsiYeh   = '\u06CC'
+	YehBarree  = '\u06D2'
+	Keheh      = '\u06A9'
+	Kaf        = '\u0643'
+	HamzaAbove = '\u0654'
+	HehYeh     = '\u06C0'
+	HehGoal    = '\u06C1'
+	Heh        = '\u0647'
+)
+
+type PersianNormalizeFilter struct {
+}
+
+func NewPersianNormalizeFilter() *PersianNormalizeFilter {
+	return &PersianNormalizeFilter{}
+}
+
+func (s *PersianNormalizeFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	for _, token := range input {
+		term := normalize(token.Term)
+		token.Term = term
+	}
+	return input
+}
+
+func normalize(input []byte) []byte {
+	runes := bytes.Runes(input)
+	for i := 0; i < len(runes); i++ {
+		switch runes[i] {
+		case FarsiYeh, YehBarree:
+			runes[i] = Yeh
+		case Keheh:
+			runes[i] = Kaf
+		case HehYeh, HehGoal:
+			runes[i] = Heh
+		case HamzaAbove: // necessary for HEH + HAMZA
+			runes = analysis.DeleteRune(runes, i)
+			i--
+		}
+	}
+	return analysis.BuildTermFromRunes(runes)
+}
+
+func NormalizerFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	return NewPersianNormalizeFilter(), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(NormalizeName, NormalizerFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}