gitea/modules/util/truncate.go

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// Copyright 2021 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package util
import "unicode/utf8"
// SplitStringAtByteN splits a string at byte n accounting for rune boundaries. (Combining characters are not accounted for.)
func SplitStringAtByteN(input string, n int) (left, right string) {
if len(input) <= n {
left = input
return
}
if !utf8.ValidString(input) {
left = input[:n-3] + "..."
right = "..." + input[n-3:]
return
}
// in UTF8 "…" is 3 bytes so doesn't really gain us anything...
end := 0
for end <= n-3 {
_, size := utf8.DecodeRuneInString(input[end:])
if end+size > n-3 {
break
}
end += size
}
left = input[:end] + "…"
right = "…" + input[end:]
return
}