95 lines
1.7 KiB
Go
95 lines
1.7 KiB
Go
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()
|
|
}
|
|
}
|
|
}
|