Imported Upstream version 1.4upstream/1.4

1 files changed, 118 insertions, 0 deletions

diff --git a/src/mime/multipart/quotedprintable.go b/src/mime/multipart/quotedprintable.go
new file mode 100644
index 000000000..9ff4ee703
--- /dev/null
+++ b/src/mime/multipart/quotedprintable.go
@@ -0,0 +1,118 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The file define a quoted-printable decoder, as specified in RFC 2045.
+// Deviations:
+// 1. in addition to "=\r\n", "=\n" is also treated as soft line break.
+// 2. it will pass through a '\r' or '\n' not preceded by '=', consistent
+//    with other broken QP encoders & decoders.
+
+package multipart
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+)
+
+type qpReader struct {
+	br   *bufio.Reader
+	rerr error  // last read error
+	line []byte // to be consumed before more of br
+}
+
+func newQuotedPrintableReader(r io.Reader) io.Reader {
+	return &qpReader{
+		br: bufio.NewReader(r),
+	}
+}
+
+func fromHex(b byte) (byte, error) {
+	switch {
+	case b >= '0' && b <= '9':
+		return b - '0', nil
+	case b >= 'A' && b <= 'F':
+		return b - 'A' + 10, nil
+	}
+	return 0, fmt.Errorf("multipart: invalid quoted-printable hex byte 0x%02x", b)
+}
+
+func (q *qpReader) readHexByte(v []byte) (b byte, err error) {
+	if len(v) < 2 {
+		return 0, io.ErrUnexpectedEOF
+	}
+	var hb, lb byte
+	if hb, err = fromHex(v[0]); err != nil {
+		return 0, err
+	}
+	if lb, err = fromHex(v[1]); err != nil {
+		return 0, err
+	}
+	return hb<<4 | lb, nil
+}
+
+func isQPDiscardWhitespace(r rune) bool {
+	switch r {
+	case '\n', '\r', ' ', '\t':
+		return true
+	}
+	return false
+}
+
+var (
+	crlf       = []byte("\r\n")
+	lf         = []byte("\n")
+	softSuffix = []byte("=")
+)
+
+func (q *qpReader) Read(p []byte) (n int, err error) {
+	for len(p) > 0 {
+		if len(q.line) == 0 {
+			if q.rerr != nil {
+				return n, q.rerr
+			}
+			q.line, q.rerr = q.br.ReadSlice('\n')
+
+			// Does the line end in CRLF instead of just LF?
+			hasLF := bytes.HasSuffix(q.line, lf)
+			hasCR := bytes.HasSuffix(q.line, crlf)
+			wholeLine := q.line
+			q.line = bytes.TrimRightFunc(wholeLine, isQPDiscardWhitespace)
+			if bytes.HasSuffix(q.line, softSuffix) {
+				rightStripped := wholeLine[len(q.line):]
+				q.line = q.line[:len(q.line)-1]
+				if !bytes.HasPrefix(rightStripped, lf) && !bytes.HasPrefix(rightStripped, crlf) {
+					q.rerr = fmt.Errorf("multipart: invalid bytes after =: %q", rightStripped)
+				}
+			} else if hasLF {
+				if hasCR {
+					q.line = append(q.line, '\r', '\n')
+				} else {
+					q.line = append(q.line, '\n')
+				}
+			}
+			continue
+		}
+		b := q.line[0]
+
+		switch {
+		case b == '=':
+			b, err = q.readHexByte(q.line[1:])
+			if err != nil {
+				return n, err
+			}
+			q.line = q.line[2:] // 2 of the 3; other 1 is done below
+		case b == '\t' || b == '\r' || b == '\n':
+			break
+		case b < ' ' || b > '~':
+			return n, fmt.Errorf("multipart: invalid unescaped byte 0x%02x in quoted-printable body", b)
+		}
+		p[0] = b
+		p = p[1:]
+		q.line = q.line[1:]
+		n++
+	}
+	return n, nil
+}