mirror of
https://github.com/42wim/matterbridge.git
synced 2024-12-11 11:42:00 -08:00
131 lines
2.7 KiB
Go
131 lines
2.7 KiB
Go
package dataurl
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"io"
|
|
"strings"
|
|
)
|
|
|
|
// Escape implements URL escaping, as defined in RFC 2397 (http://tools.ietf.org/html/rfc2397).
|
|
// It differs a bit from net/url's QueryEscape and QueryUnescape, e.g how spaces are treated (+ instead of %20):
|
|
//
|
|
// Only ASCII chars are allowed. Reserved chars are escaped to their %xx form.
|
|
// Unreserved chars are [a-z], [A-Z], [0-9], and -_.!~*\().
|
|
func Escape(data []byte) string {
|
|
var buf = new(bytes.Buffer)
|
|
for _, b := range data {
|
|
switch {
|
|
case isUnreserved(b):
|
|
buf.WriteByte(b)
|
|
default:
|
|
fmt.Fprintf(buf, "%%%02X", b)
|
|
}
|
|
}
|
|
return buf.String()
|
|
}
|
|
|
|
// EscapeString is like Escape, but taking
|
|
// a string as argument.
|
|
func EscapeString(s string) string {
|
|
return Escape([]byte(s))
|
|
}
|
|
|
|
// isUnreserved return true
|
|
// if the byte c is an unreserved char,
|
|
// as defined in RFC 2396.
|
|
func isUnreserved(c byte) bool {
|
|
return (c >= 'a' && c <= 'z') ||
|
|
(c >= 'A' && c <= 'Z') ||
|
|
(c >= '0' && c <= '9') ||
|
|
c == '-' ||
|
|
c == '_' ||
|
|
c == '.' ||
|
|
c == '!' ||
|
|
c == '~' ||
|
|
c == '*' ||
|
|
c == '\'' ||
|
|
c == '(' ||
|
|
c == ')'
|
|
}
|
|
|
|
func isHex(c byte) bool {
|
|
switch {
|
|
case c >= 'a' && c <= 'f':
|
|
return true
|
|
case c >= 'A' && c <= 'F':
|
|
return true
|
|
case c >= '0' && c <= '9':
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
// borrowed from net/url/url.go
|
|
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
|
|
}
|
|
|
|
// Unescape unescapes a character sequence
|
|
// escaped with Escape(String?).
|
|
func Unescape(s string) ([]byte, error) {
|
|
var buf = new(bytes.Buffer)
|
|
reader := strings.NewReader(s)
|
|
|
|
for {
|
|
r, size, err := reader.ReadRune()
|
|
if err == io.EOF {
|
|
break
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if size > 1 {
|
|
return nil, fmt.Errorf("rfc2396: non-ASCII char detected")
|
|
}
|
|
|
|
switch r {
|
|
case '%':
|
|
eb1, err := reader.ReadByte()
|
|
if err == io.EOF {
|
|
return nil, fmt.Errorf("rfc2396: unexpected end of unescape sequence")
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if !isHex(eb1) {
|
|
return nil, fmt.Errorf("rfc2396: invalid char 0x%x in unescape sequence", r)
|
|
}
|
|
eb0, err := reader.ReadByte()
|
|
if err == io.EOF {
|
|
return nil, fmt.Errorf("rfc2396: unexpected end of unescape sequence")
|
|
}
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if !isHex(eb0) {
|
|
return nil, fmt.Errorf("rfc2396: invalid char 0x%x in unescape sequence", r)
|
|
}
|
|
buf.WriteByte(unhex(eb0) + unhex(eb1)*16)
|
|
default:
|
|
buf.WriteByte(byte(r))
|
|
}
|
|
}
|
|
return buf.Bytes(), nil
|
|
}
|
|
|
|
// UnescapeToString is like Unescape, but returning
|
|
// a string.
|
|
func UnescapeToString(s string) (string, error) {
|
|
b, err := Unescape(s)
|
|
return string(b), err
|
|
}
|