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runestring.go
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/
runestring.go
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package matchr
type runestring []rune
// A safe way to index a runestring. It will return a null rune if you try
// to index outside of the bounds of the runestring.
func (r *runestring) SafeAt(pos int) rune {
if pos < 0 || pos >= len(*r) {
return 0
} else {
return (*r)[pos]
}
}
// A safe way to obtain a substring of a runestring. It will return a null
// string ("") if you index somewhere outside its bounds.
func (r *runestring) SafeSubstr(pos int, length int) string {
if pos < 0 || pos > len(*r) || (pos+length) > len(*r) {
return ""
} else {
return string((*r)[pos : pos+length])
}
}
// Delete characters at positions pos. It will do nothing if you provide
// an index outside the bounds of the runestring.
func (r *runestring) Del(pos ...int) {
for _, i := range pos {
if i >= 0 && i <= len(*r) {
*r = append((*r)[:i], (*r)[i+1:]...)
}
}
}
// A helper to determine if any substrings exist within the given runestring.
func (r *runestring) Contains(start int, length int, criteria ...string) bool {
substring := r.SafeSubstr(start, length)
for _, c := range criteria {
if substring == c {
return true
}
}
return false
}