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
