1
// Copyright 2012 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.
5
// The file define a quoted-printable decoder, as specified in RFC 2045.
7
// 1. in addition to "=\r\n", "=\n" is also treated as soft line break.
8
// 2. it will pass through a '\r' or '\n' not preceded by '=', consistent
9
// with other broken QP encoders & decoders.
20
type qpReader struct {
22
rerr error // last read error
23
line []byte // to be consumed before more of br
26
func newQuotedPrintableReader(r io.Reader) io.Reader {
28
br: bufio.NewReader(r),
32
func fromHex(b byte) (byte, error) {
34
case b >= '0' && b <= '9':
36
case b >= 'A' && b <= 'F':
37
return b - 'A' + 10, nil
39
return 0, fmt.Errorf("multipart: invalid quoted-printable hex byte 0x%02x", b)
42
func (q *qpReader) readHexByte(v []byte) (b byte, err error) {
44
return 0, io.ErrUnexpectedEOF
47
if hb, err = fromHex(v[0]); err != nil {
50
if lb, err = fromHex(v[1]); err != nil {
53
return hb<<4 | lb, nil
56
func isQPDiscardWhitespace(r rune) bool {
58
case '\n', '\r', ' ', '\t':
67
softSuffix = []byte("=")
70
func (q *qpReader) Read(p []byte) (n int, err error) {
76
q.line, q.rerr = q.br.ReadSlice('\n')
78
// Does the line end in CRLF instead of just LF?
79
hasLF := bytes.HasSuffix(q.line, lf)
80
hasCR := bytes.HasSuffix(q.line, crlf)
82
q.line = bytes.TrimRightFunc(wholeLine, isQPDiscardWhitespace)
83
if bytes.HasSuffix(q.line, softSuffix) {
84
rightStripped := wholeLine[len(q.line):]
85
q.line = q.line[:len(q.line)-1]
86
if !bytes.HasPrefix(rightStripped, lf) && !bytes.HasPrefix(rightStripped, crlf) {
87
q.rerr = fmt.Errorf("multipart: invalid bytes after =: %q", rightStripped)
91
q.line = append(q.line, '\r', '\n')
93
q.line = append(q.line, '\n')
102
b, err = q.readHexByte(q.line[1:])
106
q.line = q.line[2:] // 2 of the 3; other 1 is done below
107
case b == '\t' || b == '\r' || b == '\n':
109
case b < ' ' || b > '~':
110
return n, fmt.Errorf("multipart: invalid unescaped byte 0x%02x in quoted-printable body", b)