/
snake_case.go
49 lines (45 loc) · 1.19 KB
/
snake_case.go
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package esxsql
import (
"strings"
)
func ToSnakeCase(s string) string {
const delimiter = '_'
s = strings.TrimSpace(s)
n := strings.Builder{}
n.Grow(len(s) + 2) // nominal 2 bytes of extra space for inserted delimiters
for i, v := range []byte(s) {
vIsCap := v >= 'A' && v <= 'Z'
vIsLow := v >= 'a' && v <= 'z'
if vIsCap {
v += 'a'
v -= 'A'
}
// treat acronyms as words, eg for JSONData -> JSON is a whole word
if i+1 < len(s) {
next := s[i+1]
vIsNum := v >= '0' && v <= '9'
nextIsCap := next >= 'A' && next <= 'Z'
nextIsLow := next >= 'a' && next <= 'z'
nextIsNum := next >= '0' && next <= '9'
// add underscore if next letter case type is changed
if (vIsCap && (nextIsLow || nextIsNum)) || (vIsLow && (nextIsCap || nextIsNum)) || (vIsNum && (nextIsCap || nextIsLow)) {
if vIsCap && nextIsLow {
if prevIsCap := i > 0 && s[i-1] >= 'A' && s[i-1] <= 'Z'; prevIsCap {
n.WriteByte(delimiter)
}
}
n.WriteByte(v)
if vIsLow || vIsNum || nextIsNum {
n.WriteByte(delimiter)
}
continue
}
}
if (v == ' ' || v == '_' || v == '-') && uint8(v) != 0 {
n.WriteByte(delimiter)
} else {
n.WriteByte(v)
}
}
return n.String()
}