1// Use of this source code is governed by a BSD-style
 2// license that can be found in the LICENSE file.
 3
 4// Package regexp implements a simple regular expression library.
 5
 6// QuoteMeta func is copied here to avoid linking the entire Regexp library.
 7
 8package rubex
 9
10func special(c int) bool {
11	for _, r := range `\.+*?()|[]^$` {
12		if c == int(r) {
13			return true
14		}
15	}
16	return false
17}
18
19// QuoteMeta returns a string that quotes all regular expression metacharacters
20// inside the argument text; the returned string is a regular expression matching
21// the literal text.  For example, QuoteMeta(`[foo]`) returns `\[foo\]`.
22func QuoteMeta(s string) string {
23	b := make([]byte, 2*len(s))
24
25	// A byte loop is correct because all metacharacters are ASCII.
26	j := 0
27	for i := 0; i < len(s); i++ {
28		if special(int(s[i])) {
29			b[j] = '\\'
30			j++
31		}
32		b[j] = s[i]
33		j++
34	}
35	return string(b[0:j])
36}