93 lines
2.5 KiB
Go
93 lines
2.5 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
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// except in compliance with the License. You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed under the
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// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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package rune_tokenizer
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import (
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"unicode/utf8"
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"github.com/couchbaselabs/bleve/analysis"
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)
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type RuneTokenizer struct {
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c RuneTokenClassifer
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}
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func NewRuneTokenizer(c RuneTokenClassifer) *RuneTokenizer {
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return &RuneTokenizer{
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c: c,
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}
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}
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func (rt *RuneTokenizer) Tokenize(input []byte) analysis.TokenStream {
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// rv := make(analysis.TokenStream, 0)
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// runes := bytes.Runes(input)
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// nextTokenRunes := make([]rune, 0)
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// for _, r := range runes {
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// }
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// return rv
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rv := make(analysis.TokenStream, 0)
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currentInputPos := 0
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nextTokenRunes := make([]rune, 0)
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tokenPos := 1
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tokenStart := 0
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nextRune, nextRuneLen := utf8.DecodeRune(input[currentInputPos:])
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for nextRune != utf8.RuneError && currentInputPos < len(input) {
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if rt.c.InToken(nextRune) {
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nextTokenRunes = append(nextTokenRunes, nextRune)
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} else {
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// end the last loken, if one is building
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if len(nextTokenRunes) > 0 {
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nextToken := analysis.Token{
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Term: buildTermFromRunes(nextTokenRunes),
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Position: tokenPos,
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Start: tokenStart,
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End: currentInputPos,
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Type: analysis.AlphaNumeric,
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}
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rv = append(rv, &nextToken)
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nextTokenRunes = make([]rune, 0)
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tokenPos++
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}
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tokenStart = currentInputPos + nextRuneLen
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}
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currentInputPos += nextRuneLen
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nextRune, nextRuneLen = utf8.DecodeRune(input[currentInputPos:])
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}
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// build one last token if we didn't end on whitespace
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if len(nextTokenRunes) > 0 {
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nextToken := analysis.Token{
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Term: buildTermFromRunes(nextTokenRunes),
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Position: tokenPos,
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Start: tokenStart,
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End: len(input),
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Type: analysis.AlphaNumeric,
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}
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rv = append(rv, &nextToken)
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nextTokenRunes = make([]rune, 0)
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tokenPos++
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}
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return rv
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}
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func buildTermFromRunes(runes []rune) []byte {
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rv := make([]byte, 0, len(runes)*4)
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for _, r := range runes {
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runeBytes := make([]byte, utf8.RuneLen(r))
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utf8.EncodeRune(runeBytes, r)
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rv = append(rv, runeBytes...)
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}
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return rv
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}
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