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gitea/vendor/github.com/blevesearch/bleve/analysis/token/camelcase/camelcase.go

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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 camelcase
import (
"bytes"
"unicode/utf8"
"github.com/blevesearch/bleve/analysis"
"github.com/blevesearch/bleve/registry"
)
const Name = "camelCase"
// CamelCaseFilter splits a given token into a set of tokens where each resulting token
// falls into one the following classes:
// 1) Upper case followed by lower case letters.
// Terminated by a number, an upper case letter, and a non alpha-numeric symbol.
// 2) Upper case followed by upper case letters.
// Terminated by a number, an upper case followed by a lower case letter, and a non alpha-numeric symbol.
// 3) Lower case followed by lower case letters.
// Terminated by a number, an upper case letter, and a non alpha-numeric symbol.
// 4) Number followed by numbers.
// Terminated by a letter, and a non alpha-numeric symbol.
// 5) Non alpha-numeric symbol followed by non alpha-numeric symbols.
// Terminated by a number, and a letter.
//
// It does a one-time sequential pass over an input token, from left to right.
// The scan is greedy and generates the longest substring that fits into one of the classes.
//
// See the test file for examples of classes and their parsings.
type CamelCaseFilter struct{}
func NewCamelCaseFilter() *CamelCaseFilter {
return &CamelCaseFilter{}
}
func (f *CamelCaseFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
rv := make(analysis.TokenStream, 0, len(input))
nextPosition := 1
for _, token := range input {
runeCount := utf8.RuneCount(token.Term)
runes := bytes.Runes(token.Term)
p := NewParser(runeCount, nextPosition, token.Start)
for i := 0; i < runeCount; i++ {
if i+1 >= runeCount {
p.Push(runes[i], nil)
} else {
p.Push(runes[i], &runes[i+1])
}
}
rv = append(rv, p.FlushTokens()...)
nextPosition = p.NextPosition()
}
return rv
}
func CamelCaseFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
return NewCamelCaseFilter(), nil
}
func init() {
registry.RegisterTokenFilter(Name, CamelCaseFilterConstructor)
}