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persian_normalize.go
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persian_normalize.go
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// 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/analysis"
"github.com/blevesearch/bleve/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() {
registry.RegisterTokenFilter(NormalizeName, NormalizerFilterConstructor)
}