Source file src/pkg/cmd/internal/objabi/path.go

     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	

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