mirror of
https://codeberg.org/forgejo/forgejo.git
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b6a95a8cb3
* Dropped unused codekit config * Integrated dynamic and static bindata for public * Ignore public bindata * Add a general generate make task * Integrated flexible public assets into web command * Updated vendoring, added all missiong govendor deps * Made the linter happy with the bindata and dynamic code * Moved public bindata definition to modules directory * Ignoring the new bindata path now * Updated to the new public modules import path * Updated public bindata command and drop the new prefix
280 lines
6.2 KiB
Go
280 lines
6.2 KiB
Go
package quotedprintable
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import (
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"bytes"
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"encoding/base64"
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"errors"
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"fmt"
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"io"
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"strings"
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"unicode"
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"unicode/utf8"
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)
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// A WordEncoder is a RFC 2047 encoded-word encoder.
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type WordEncoder byte
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const (
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// BEncoding represents Base64 encoding scheme as defined by RFC 2045.
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BEncoding = WordEncoder('b')
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// QEncoding represents the Q-encoding scheme as defined by RFC 2047.
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QEncoding = WordEncoder('q')
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)
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var (
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errInvalidWord = errors.New("mime: invalid RFC 2047 encoded-word")
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)
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// Encode returns the encoded-word form of s. If s is ASCII without special
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// characters, it is returned unchanged. The provided charset is the IANA
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// charset name of s. It is case insensitive.
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func (e WordEncoder) Encode(charset, s string) string {
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if !needsEncoding(s) {
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return s
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}
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return e.encodeWord(charset, s)
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}
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func needsEncoding(s string) bool {
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for _, b := range s {
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if (b < ' ' || b > '~') && b != '\t' {
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return true
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}
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}
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return false
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}
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// encodeWord encodes a string into an encoded-word.
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func (e WordEncoder) encodeWord(charset, s string) string {
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buf := getBuffer()
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defer putBuffer(buf)
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buf.WriteString("=?")
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buf.WriteString(charset)
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buf.WriteByte('?')
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buf.WriteByte(byte(e))
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buf.WriteByte('?')
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if e == BEncoding {
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w := base64.NewEncoder(base64.StdEncoding, buf)
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io.WriteString(w, s)
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w.Close()
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} else {
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enc := make([]byte, 3)
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for i := 0; i < len(s); i++ {
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b := s[i]
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switch {
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case b == ' ':
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buf.WriteByte('_')
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case b <= '~' && b >= '!' && b != '=' && b != '?' && b != '_':
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buf.WriteByte(b)
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default:
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enc[0] = '='
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enc[1] = upperhex[b>>4]
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enc[2] = upperhex[b&0x0f]
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buf.Write(enc)
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}
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}
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}
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buf.WriteString("?=")
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return buf.String()
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}
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const upperhex = "0123456789ABCDEF"
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// A WordDecoder decodes MIME headers containing RFC 2047 encoded-words.
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type WordDecoder struct {
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// CharsetReader, if non-nil, defines a function to generate
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// charset-conversion readers, converting from the provided
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// charset into UTF-8.
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// Charsets are always lower-case. utf-8, iso-8859-1 and us-ascii charsets
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// are handled by default.
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// One of the the CharsetReader's result values must be non-nil.
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CharsetReader func(charset string, input io.Reader) (io.Reader, error)
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}
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// Decode decodes an encoded-word. If word is not a valid RFC 2047 encoded-word,
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// word is returned unchanged.
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func (d *WordDecoder) Decode(word string) (string, error) {
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fields := strings.Split(word, "?") // TODO: remove allocation?
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if len(fields) != 5 || fields[0] != "=" || fields[4] != "=" || len(fields[2]) != 1 {
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return "", errInvalidWord
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}
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content, err := decode(fields[2][0], fields[3])
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if err != nil {
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return "", err
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}
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buf := getBuffer()
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defer putBuffer(buf)
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if err := d.convert(buf, fields[1], content); err != nil {
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return "", err
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}
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return buf.String(), nil
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}
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// DecodeHeader decodes all encoded-words of the given string. It returns an
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// error if and only if CharsetReader of d returns an error.
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func (d *WordDecoder) DecodeHeader(header string) (string, error) {
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// If there is no encoded-word, returns before creating a buffer.
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i := strings.Index(header, "=?")
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if i == -1 {
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return header, nil
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}
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buf := getBuffer()
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defer putBuffer(buf)
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buf.WriteString(header[:i])
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header = header[i:]
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betweenWords := false
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for {
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start := strings.Index(header, "=?")
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if start == -1 {
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break
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}
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cur := start + len("=?")
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i := strings.Index(header[cur:], "?")
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if i == -1 {
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break
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}
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charset := header[cur : cur+i]
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cur += i + len("?")
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if len(header) < cur+len("Q??=") {
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break
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}
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encoding := header[cur]
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cur++
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if header[cur] != '?' {
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break
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}
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cur++
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j := strings.Index(header[cur:], "?=")
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if j == -1 {
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break
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}
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text := header[cur : cur+j]
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end := cur + j + len("?=")
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content, err := decode(encoding, text)
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if err != nil {
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betweenWords = false
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buf.WriteString(header[:start+2])
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header = header[start+2:]
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continue
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}
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// Write characters before the encoded-word. White-space and newline
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// characters separating two encoded-words must be deleted.
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if start > 0 && (!betweenWords || hasNonWhitespace(header[:start])) {
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buf.WriteString(header[:start])
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}
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if err := d.convert(buf, charset, content); err != nil {
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return "", err
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}
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header = header[end:]
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betweenWords = true
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}
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if len(header) > 0 {
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buf.WriteString(header)
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}
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return buf.String(), nil
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}
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func decode(encoding byte, text string) ([]byte, error) {
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switch encoding {
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case 'B', 'b':
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return base64.StdEncoding.DecodeString(text)
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case 'Q', 'q':
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return qDecode(text)
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}
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return nil, errInvalidWord
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}
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func (d *WordDecoder) convert(buf *bytes.Buffer, charset string, content []byte) error {
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switch {
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case strings.EqualFold("utf-8", charset):
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buf.Write(content)
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case strings.EqualFold("iso-8859-1", charset):
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for _, c := range content {
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buf.WriteRune(rune(c))
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}
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case strings.EqualFold("us-ascii", charset):
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for _, c := range content {
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if c >= utf8.RuneSelf {
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buf.WriteRune(unicode.ReplacementChar)
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} else {
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buf.WriteByte(c)
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}
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}
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default:
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if d.CharsetReader == nil {
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return fmt.Errorf("mime: unhandled charset %q", charset)
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}
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r, err := d.CharsetReader(strings.ToLower(charset), bytes.NewReader(content))
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if err != nil {
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return err
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}
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if _, err = buf.ReadFrom(r); err != nil {
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return err
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}
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}
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return nil
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}
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// hasNonWhitespace reports whether s (assumed to be ASCII) contains at least
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// one byte of non-whitespace.
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func hasNonWhitespace(s string) bool {
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for _, b := range s {
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switch b {
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// Encoded-words can only be separated by linear white spaces which does
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// not include vertical tabs (\v).
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case ' ', '\t', '\n', '\r':
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default:
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return true
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}
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}
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return false
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}
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// qDecode decodes a Q encoded string.
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func qDecode(s string) ([]byte, error) {
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dec := make([]byte, len(s))
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n := 0
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for i := 0; i < len(s); i++ {
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switch c := s[i]; {
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case c == '_':
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dec[n] = ' '
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case c == '=':
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if i+2 >= len(s) {
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return nil, errInvalidWord
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}
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b, err := readHexByte(s[i+1], s[i+2])
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if err != nil {
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return nil, err
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}
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dec[n] = b
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i += 2
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case (c <= '~' && c >= ' ') || c == '\n' || c == '\r' || c == '\t':
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dec[n] = c
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default:
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return nil, errInvalidWord
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}
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n++
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}
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return dec[:n], nil
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}
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