Mercurial > yakumo_izuru > aya
diff vendor/github.com/dlclark/regexp2/syntax/escape.go @ 66:787b5ee0289d draft
Use vendored modules
Signed-off-by: Izuru Yakumo <yakumo.izuru@chaotic.ninja>
author | yakumo.izuru |
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date | Sun, 23 Jul 2023 13:18:53 +0000 |
parents | |
children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/vendor/github.com/dlclark/regexp2/syntax/escape.go Sun Jul 23 13:18:53 2023 +0000 @@ -0,0 +1,94 @@ +package syntax + +import ( + "bytes" + "strconv" + "strings" + "unicode" +) + +func Escape(input string) string { + b := &bytes.Buffer{} + for _, r := range input { + escape(b, r, false) + } + return b.String() +} + +const meta = `\.+*?()|[]{}^$# ` + +func escape(b *bytes.Buffer, r rune, force bool) { + if unicode.IsPrint(r) { + if strings.IndexRune(meta, r) >= 0 || force { + b.WriteRune('\\') + } + b.WriteRune(r) + return + } + + switch r { + case '\a': + b.WriteString(`\a`) + case '\f': + b.WriteString(`\f`) + case '\n': + b.WriteString(`\n`) + case '\r': + b.WriteString(`\r`) + case '\t': + b.WriteString(`\t`) + case '\v': + b.WriteString(`\v`) + default: + if r < 0x100 { + b.WriteString(`\x`) + s := strconv.FormatInt(int64(r), 16) + if len(s) == 1 { + b.WriteRune('0') + } + b.WriteString(s) + break + } + b.WriteString(`\u`) + b.WriteString(strconv.FormatInt(int64(r), 16)) + } +} + +func Unescape(input string) (string, error) { + idx := strings.IndexRune(input, '\\') + // no slashes means no unescape needed + if idx == -1 { + return input, nil + } + + buf := bytes.NewBufferString(input[:idx]) + // get the runes for the rest of the string -- we're going full parser scan on this + + p := parser{} + p.setPattern(input[idx+1:]) + for { + if p.rightMost() { + return "", p.getErr(ErrIllegalEndEscape) + } + r, err := p.scanCharEscape() + if err != nil { + return "", err + } + buf.WriteRune(r) + // are we done? + if p.rightMost() { + return buf.String(), nil + } + + r = p.moveRightGetChar() + for r != '\\' { + buf.WriteRune(r) + if p.rightMost() { + // we're done, no more slashes + return buf.String(), nil + } + // keep scanning until we get another slash + r = p.moveRightGetChar() + } + } +}