/
mapper.go
48 lines (39 loc) · 909 Bytes
/
mapper.go
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package env
import (
"strings"
"unicode"
)
// IdentityMapper returns the input string
func IdentityMapper(str string) string {
return str
}
// UnderscoreMapper converts CamelCase strings to their camel_case
// counterpart
func UnderscoreMapper(str string) string {
var (
parts = []string{}
cur = []rune{}
last2 = [2]rune{}
)
for _, c := range str {
if unicode.IsUpper(c) {
if last2[1] != 0 && unicode.IsLower(last2[1]) {
parts = append(parts, string(cur))
cur = nil
}
cur = append(cur, unicode.ToLower(c))
} else {
if last2[0] != 0 && last2[1] != 0 && unicode.IsUpper(last2[0]) && unicode.IsUpper(last2[1]) {
parts = append(parts, string(cur[:len(cur)-1]))
cur = []rune{cur[len(cur)-1]}
}
cur = append(cur, c)
}
last2[0] = last2[1]
last2[1] = c
}
if len(cur) > 0 {
parts = append(parts, string(cur))
}
return strings.Join(parts, "_")
}