restic/vendor/github.com/kurin/blazer/base/strings.go

82 lines
1.7 KiB
Go

// Copyright 2017, Google
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package base
import (
"bytes"
"errors"
"fmt"
)
func noEscape(c byte) bool {
switch c {
case '.', '_', '-', '/', '~', '!', '$', '\'', '(', ')', '*', ';', '=', ':', '@':
return true
}
return false
}
func escape(s string) string {
// cribbed from url.go, kinda
b := &bytes.Buffer{}
for i := 0; i < len(s); i++ {
switch c := s[i]; {
case c == '/':
b.WriteByte(c)
case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || '0' <= c && c <= '9':
b.WriteByte(c)
case noEscape(c):
b.WriteByte(c)
default:
fmt.Fprintf(b, "%%%X", c)
}
}
return b.String()
}
func unescape(s string) (string, error) {
b := &bytes.Buffer{}
for i := 0; i < len(s); i++ {
c := s[i]
switch c {
case '/':
b.WriteString("/")
case '+':
b.WriteString(" ")
case '%':
if len(s)-i < 3 {
return "", errors.New("unescape: bad encoding")
}
b.WriteByte(unhex(s[i+1])<<4 | unhex(s[i+2]))
i += 2
default:
b.WriteByte(c)
}
}
return b.String(), nil
}
func unhex(c byte) byte {
switch {
case '0' <= c && c <= '9':
return c - '0'
case 'a' <= c && c <= 'f':
return c - 'a' + 10
case 'A' <= c && c <= 'F':
return c - 'A' + 10
}
return 0
}