forked from Shiloh/githaven
63 lines
1.5 KiB
Go
63 lines
1.5 KiB
Go
// Copyright 2021 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package util
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import "unicode/utf8"
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// in UTF8 "…" is 3 bytes so doesn't really gain us anything...
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const (
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utf8Ellipsis = "…"
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asciiEllipsis = "..."
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)
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// SplitStringAtByteN splits a string at byte n accounting for rune boundaries. (Combining characters are not accounted for.)
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func SplitStringAtByteN(input string, n int) (left, right string) {
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if len(input) <= n {
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return input, ""
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}
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if !utf8.ValidString(input) {
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if n-3 < 0 {
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return input, ""
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}
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return input[:n-3] + asciiEllipsis, asciiEllipsis + input[n-3:]
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}
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end := 0
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for end <= n-3 {
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_, size := utf8.DecodeRuneInString(input[end:])
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if end+size > n-3 {
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break
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}
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end += size
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}
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return input[:end] + utf8Ellipsis, utf8Ellipsis + input[end:]
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}
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// SplitStringAtRuneN splits a string at rune n accounting for rune boundaries. (Combining characters are not accounted for.)
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func SplitStringAtRuneN(input string, n int) (left, right string) {
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if !utf8.ValidString(input) {
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if len(input) <= n || n-3 < 0 {
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return input, ""
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}
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return input[:n-3] + asciiEllipsis, asciiEllipsis + input[n-3:]
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}
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if utf8.RuneCountInString(input) <= n {
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return input, ""
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}
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count := 0
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end := 0
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for count < n-1 {
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_, size := utf8.DecodeRuneInString(input[end:])
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end += size
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count++
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}
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return input[:end] + utf8Ellipsis, utf8Ellipsis + input[end:]
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}
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