1 // Copyright 2017 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 package objabi
6 7 import "strings"
8 9 // PathToPrefix converts raw string to the prefix that will be used in the
10 // symbol table. All control characters, space, '%' and '"', as well as
11 // non-7-bit clean bytes turn into %xx. The period needs escaping only in the
12 // last segment of the path, and it makes for happier users if we escape that as
13 // little as possible.
14 func PathToPrefix(s string) string {
15 slash := strings.LastIndex(s, "/")
16 // check for chars that need escaping
17 n := 0
18 for r := 0; r < len(s); r++ {
19 if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
20 n++
21 }
22 }
23 24 // quick exit
25 if n == 0 {
26 return s
27 }
28 29 // escape
30 const hex = "0123456789abcdef"
31 p := make([]byte, 0, len(s)+2*n)
32 for r := 0; r < len(s); r++ {
33 if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
34 p = append(p, '%', hex[c>>4], hex[c&0xF])
35 } else {
36 p = append(p, c)
37 }
38 }
39 40 return string(p)
41 }
42