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// Copyright (c) 2016 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 character
import (
"unicode/utf8"
"github.com/blevesearch/bleve/analysis"
)
type IsTokenRune func(r rune) bool
type CharacterTokenizer struct {
isTokenRun IsTokenRune
}
func NewCharacterTokenizer(f IsTokenRune) *CharacterTokenizer {
return &CharacterTokenizer{
isTokenRun: f,
}
}
func (c *CharacterTokenizer) Tokenize(input []byte) analysis.TokenStream {
rv := make(analysis.TokenStream, 0, 1024)
offset := 0
start := 0
end := 0
count := 0
for currRune, size := utf8.DecodeRune(input[offset:]); currRune != utf8.RuneError; currRune, size = utf8.DecodeRune(input[offset:]) {
isToken := c.isTokenRun(currRune)
if isToken {
end = offset + size
} else {
if end-start > 0 {
// build token
rv = append(rv, &analysis.Token{
Term: input[start:end],
Start: start,
End: end,
Position: count + 1,
Type: analysis.AlphaNumeric,
})
count++
}
start = offset + size
end = start
}
offset += size
}
// if we ended in the middle of a token, finish it
if end-start > 0 {
// build token
rv = append(rv, &analysis.Token{
Term: input[start:end],
Start: start,
End: end,
Position: count + 1,
Type: analysis.AlphaNumeric,
})
}
return rv
}