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transform.go
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transform.go
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// Copyright (C) 2019 ScyllaDB
// Use of this source code is governed by a ALv2-style
// license that can be found in the LICENSE file.
package reflectx
import (
"fmt"
"unicode"
)
// CamelToSnakeASCII converts camel case strings to snake case. For performance
// reasons it only works with ASCII strings.
func CamelToSnakeASCII(s string) string {
buf := []byte(s)
out := make([]byte, 0, len(buf)+3)
l := len(buf)
for i := 0; i < l; i++ {
if !(allowedBindRune(buf[i]) || buf[i] == '_') {
panic(fmt.Sprint("not allowed name ", s))
}
b := rune(buf[i])
if unicode.IsUpper(b) {
if i > 0 && buf[i-1] != '_' && (unicode.IsLower(rune(buf[i-1])) || (i+1 < l && unicode.IsLower(rune(buf[i+1])))) {
out = append(out, '_')
}
b = unicode.ToLower(b)
}
out = append(out, byte(b))
}
return string(out)
}
func allowedBindRune(b byte) bool {
return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || (b >= '0' && b <= '9')
}