;;; qp.el --- Quoted-Printable functions -*- lexical-binding:t -*- ;; Copyright (C) 1998-2024 Free Software Foundation, Inc. ;; Author: Lars Magne Ingebrigtsen ;; Keywords: mail, extensions ;; This file is part of GNU Emacs. ;; GNU Emacs is free software: you can redistribute it and/or modify ;; it under the terms of the GNU General Public License as published by ;; the Free Software Foundation, either version 3 of the License, or ;; (at your option) any later version. ;; GNU Emacs is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; You should have received a copy of the GNU General Public License ;; along with GNU Emacs. If not, see . ;;; Commentary: ;; Functions for encoding and decoding quoted-printable text as ;; defined in RFC 2045. ;;; Code: ;;;###autoload (defun quoted-printable-decode-region (from to &optional coding-system) "Decode quoted-printable in the region between FROM and TO, per RFC 2045. If CODING-SYSTEM is non-nil, decode bytes into characters with that coding-system. Interactively, you can supply the CODING-SYSTEM argument with \\[universal-coding-system-argument]. The CODING-SYSTEM argument is a historical hangover and is deprecated. QP encodes raw bytes and should be decoded into raw bytes. Decoding them into characters should be done separately." (interactive ;; Let the user determine the coding system with "C-x RET c". (list (region-beginning) (region-end) coding-system-for-read)) (when (and coding-system (not (coding-system-p coding-system))) ; e.g. `ascii' from Gnus (setq coding-system nil)) (save-excursion (save-restriction ;; RFC 2045: ``An "=" followed by two hexadecimal digits, one ;; or both of which are lowercase letters in "abcdef", is ;; formally illegal. A robust implementation might choose to ;; recognize them as the corresponding uppercase letters.'' (let ((case-fold-search t)) (narrow-to-region from to) ;; Do this in case we're called from Gnus, say, in a buffer ;; which already contains non-ASCII characters which would ;; then get doubly-decoded below. (if coding-system (encode-coding-region (point-min) (point-max) coding-system)) (goto-char (point-min)) (while (and (skip-chars-forward "^=") (not (eobp))) (cond ((eq (char-after (1+ (point))) ?\n) (delete-char 2)) ((looking-at "\\(=[0-9A-F][0-9A-F]\\)+") ;; Decode this sequence at once; i.e. by a single ;; deletion and insertion. (let* ((n (/ (- (match-end 0) (point)) 3)) (str (make-string n 0))) (dotimes (i n) (let ((n1 (char-after (1+ (point)))) (n2 (char-after (+ 2 (point))))) (aset str i (+ (* 16 (- n1 (if (<= n1 ?9) ?0 (if (<= n1 ?F) (- ?A 10) (- ?a 10))))) (- n2 (if (<= n2 ?9) ?0 (if (<= n2 ?F) (- ?A 10) (- ?a 10))))))) (forward-char 3)) (delete-region (match-beginning 0) (match-end 0)) (insert str))) (t (message "Malformed quoted-printable text") (forward-char))))) (if coding-system (decode-coding-region (point-min) (point-max) coding-system))))) (defun quoted-printable-decode-string (string &optional coding-system) "Decode the quoted-printable encoded STRING and return the result. If CODING-SYSTEM is non-nil, decode the string with coding-system. Use of CODING-SYSTEM is deprecated; this function should deal with raw bytes, and coding conversion should be done separately." (with-temp-buffer (set-buffer-multibyte nil) (insert string) (quoted-printable-decode-region (point-min) (point-max) coding-system) (buffer-string))) (defun quoted-printable-encode-region (from to &optional fold class) "Quoted-printable encode the region between FROM and TO per RFC 2045. If FOLD, fold long lines at 76 characters (as required by the RFC). If CLASS is non-nil, translate the characters not matched by that regexp class, which is in the form expected by `skip-chars-forward'. You should probably avoid non-ASCII characters in this arg. If `mm-use-ultra-safe-encoding' is set, fold lines unconditionally and encode lines starting with \"From\"." (interactive "r") (unless class ;; Avoid using 8bit characters. = is \075. ;; Equivalent to "^\000-\007\013\015-\037\200-\377=" (setq class "\010-\012\014\040-\074\076-\177")) (save-excursion (goto-char from) (if (re-search-forward "[^\x0-\x7f\x80-\xff]" to t) (error "Multibyte character in QP encoding region")) (save-restriction (narrow-to-region from to) ;; Encode all the non-ascii and control characters. (goto-char (point-min)) (while (and (skip-chars-forward class) (not (eobp))) (insert (prog1 (format "=%02X" (get-byte)) (delete-char 1)))) ;; Encode white space at the end of lines. (goto-char (point-min)) (while (re-search-forward "[ \t]+$" nil t) (goto-char (match-beginning 0)) (while (not (eolp)) (insert (prog1 (format "=%02X" (get-byte)) (delete-char 1))))) (let ((ultra (and (boundp 'mm-use-ultra-safe-encoding) mm-use-ultra-safe-encoding))) (when (or fold ultra) (let ((tab-width 1) ; HTAB is one character. (case-fold-search nil)) (goto-char (point-min)) (while (not (eobp)) ;; In ultra-safe mode, encode "From " at the beginning ;; of a line. (when ultra (if (looking-at "From ") (replace-match "From=20" nil t) (if (looking-at "-") (replace-match "=2D" nil t)))) (end-of-line) ;; Fold long lines. (while (> (current-column) 76) ; tab-width must be 1. (beginning-of-line) (forward-char 75) ; 75 chars plus an "=" (search-backward "=" (- (point) 2) t) (insert "=\n") (end-of-line)) (forward-line)))))))) (defun quoted-printable-encode-string (string) "Encode the STRING as quoted-printable and return the result." (with-temp-buffer (if (multibyte-string-p string) (set-buffer-multibyte 'to) (set-buffer-multibyte nil)) (insert string) (quoted-printable-encode-region (point-min) (point-max)) (buffer-string))) (provide 'qp) ;;; qp.el ends here