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// _ _
// __ _____ __ ___ ___ __ _| |_ ___
// \ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \
// \ V V / __/ (_| |\ V /| | (_| | || __/
// \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___|
//
// Copyright © 2016 - 2024 Weaviate B.V. All rights reserved.
//
// CONTACT: [email protected]
//
package inverted
import (
"bytes"
"regexp"
"github.com/pkg/errors"
)
type likeRegexp struct {
optimizable bool
min []byte
regexp *regexp.Regexp
}
func parseLikeRegexp(in []byte) (*likeRegexp, error) {
r, err := regexp.Compile(transformLikeStringToRegexp(in))
if err != nil {
return nil, errors.Wrap(err, "compile regex from 'like' string")
}
min, ok := optimizable(in)
return &likeRegexp{
regexp: r,
min: min,
optimizable: ok,
}, nil
}
func transformLikeStringToRegexp(in []byte) string {
in = bytes.ReplaceAll(in, []byte("?"), []byte("."))
in = bytes.ReplaceAll(in, []byte("*"), []byte(".*"))
return "^" + string(in) + "$"
}
func optimizable(in []byte) ([]byte, bool) {
maxCharsWithoutWildcard := 0
for _, char := range in {
if isWildcardCharacter(char) {
break
}
maxCharsWithoutWildcard++
}
return in[:maxCharsWithoutWildcard], maxCharsWithoutWildcard > 0
}
func isWildcardCharacter(in byte) bool {
return in == '?' || in == '*'
}
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