-;;; utf7.el --- UTF-7 encoding/decoding for Emacs
-;; Copyright (C) 1999 Free Software Foundation, Inc.
+;;; utf7.el --- UTF-7 encoding/decoding for Emacs -*-coding: iso-8859-1;-*-
+;; Copyright (C) 1999, 2000, 2003 Free Software Foundation, Inc.
-;; Author: Jon K Hellan <hellan@item.ntnu.no>
+;; Author: Jon K Hellan <hellan@acm.org>
+;; Maintainer: bugs@gnus.org
;; Keywords: mail
-;; This file is part of GNU Emacs, but the same permissions apply
-
;; 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 2, or (at your option)
;; Boston, MA 02111-1307, USA.
;;; Commentary:
-;;; UTF-7 - A Mail-Safe Transformation Format of Unicode - RFC 2152
-;;; This is a transformation format of Unicode that contains only 7-bit
-;;; ASCII octets and is intended to be readable by humans in the limiting
-;;; case that the document consists of characters from the US-ASCII
-;;; repertoire.
-;;; In short, runs of characters outside US-ASCII are encoded as base64
-;;; inside delimiters.
-;;; A variation of UTF-7 is specified in IMAP 4rev1 (RFC 2060) as the way
-;;; to represent characters outside US-ASCII in mailbox names in IMAP.
-;;; This library supports both variants, but the IMAP variation was the
-;;; reason I wrote it.
-;;; The routines convert UTF-7 -> UTF-16 (16 bit encoding of Unicode)
-;;; -> current character set, and vice versa.
-;;; However, until Emacs supports Unicode, the only Emacs character set
-;;; supported here is ISO-8859.1, which can trivially be converted to/from
-;;; Unicode.
-;;; When decoding results in a character outside the Emacs character set,
-;;; an error is thrown. It is up to the application to recover.
-;;; Modified 8 December 1999 by Yuuichi Teranishi so that it will work under
-;;; Emacs+Mule-UCS and XEmacs.
+;; UTF-7 - A Mail-Safe Transformation Format of Unicode - RFC 2152
+;; This is a transformation format of Unicode that contains only 7-bit
+;; ASCII octets and is intended to be readable by humans in the limiting
+;; case that the document consists of characters from the US-ASCII
+;; repertoire.
+;; In short, runs of characters outside US-ASCII are encoded as base64
+;; inside delimiters.
+;; A variation of UTF-7 is specified in IMAP 4rev1 (RFC 2060) as the way
+;; to represent characters outside US-ASCII in mailbox names in IMAP.
+;; This library supports both variants, but the IMAP variation was the
+;; reason I wrote it.
+;; The routines convert UTF-7 -> UTF-16 (16 bit encoding of Unicode)
+;; -> current character set, and vice versa.
+;; However, until Emacs supports Unicode, the only Emacs character set
+;; supported here is ISO-8859.1, which can trivially be converted to/from
+;; Unicode.
+;; When decoding results in a character outside the Emacs character set,
+;; an error is thrown. It is up to the application to recover.
+
+;; UTF-7 should be done by providing a coding system. Mule-UCS does
+;; already, but I don't know if it does the IMAP version and it's not
+;; clear whether that should really be a coding system. The UTF-16
+;; part of the conversion can be done with coding systems available
+;; with Mule-UCS or some versions of Emacs. Unfortunately these were
+;; done wrongly (regarding handling of byte-order marks and how the
+;; variants were named), so we don't have a consistent name for the
+;; necessary coding system. The code below doesn't seem to DTRT
+;; generally. E.g.:
+;;
+;; (utf7-encode "a+£")
+;; => "a+ACsAow-"
+;;
+;; $ echo "a+£"|iconv -f iso-8859-1 -t utf-7
+;; a+-+AKM
+;;
+;; -- fx
+
+;; Modified 5 May 2004 by Yuuichi Teranishi so that it can run with APEL/FLIM
+;; instead of mm-util in Gnus.
+;;
+;; * Use find-coding-system instead of mm-coding-system-p.
+;; * Use mel.el instead of base64.el.
+;; * Don't use mm-with-unibyte-current-buffer etc.
+;; * Do nothing if utf-16 coding system is not found.
+
+;; Modified 31 Aug 2004 by Yuuichi Teranishi so that it can avoid the bug of
+;; Emacs 21.3 release version.
;;; Code:
(eval-when-compile (require 'cl))
-(eval-when-compile (require 'pces))
-(eval-when-compile (require 'static))
-
-;; base64 stuff.
-;;(static-if (and (fboundp 'base64-decode-region)
-;; (subrp (symbol-function 'base64-decode-region)))
-;; (eval-and-compile (fset 'utf7-base64-decode-region 'base64-decode-region))
-;; (require 'mel)
-;; (defun utf7-base64-decode-region (start end)
-;; (fset 'utf7-base64-decode-string
-;; (symbol-function (mel-find-function 'mime-decode-region "base64")))
-;; (utf7-base64-decode-region start end)))
-
-;;(static-if (and (fboundp 'base64-encode-region)
-;; (subrp (symbol-function 'base64-encode-region)))
-;; (eval-and-compile (fset 'utf7-base64-encode-region 'base64-encode-region))
-;; (defun utf7-base64-encode-string (start end)
-;; (fset 'utf7-base64-encode-region
-;; (symbol-function (mel-find-function 'mime-encode-region "base64")))
-;; (utf7-base64-encode-region start end)))
-
-;; On XEmacs which does not support UTF-16 have to use u7tou8 and u8tou7.
-;; These programs are included in
-;; ftp://ftp.ifcss.org/pub/software/unix/convert/utf7.tar.gz
-(defvar utf7-utf7-to-utf8-program "u7tou8"
- "Program to convert utf7 to utf8.")
-(defvar utf7-utf8-to-utf7-program "u8tou7"
- "Program to convert utf8 to utf7.")
-
-(defvar utf7-direct-encoding-chars " -%'-*,-[]-} \t\n\r"
- "Characters ranges which do not need escaping in UTF-7")
-(defvar utf7-imap-direct-encoding-chars
- (concat utf7-direct-encoding-chars "+\\\\~")
- "Characters ranges which do not need escaping in the IMAP modified variant of UTF-7")
-
-(defsubst utf7-imap-get-pad-length (len modulus)
+(require 'pces)
+(require 'mel)
+
+;; base64 encoding/decoding
+(defun utf7-base64-encode-region (beg end &optional no-line-break))
+(defun utf7-base64-decode-region (beg end))
+(fset 'utf7-base64-encode-region
+ (mel-find-function 'mime-encode-region "base64"))
+(fset 'utf7-base64-decode-region
+ (mel-find-function 'mime-decode-region "base64"))
+
+(defconst utf7-direct-encoding-chars " -%'-*,-[]-}"
+ "Character ranges which do not need escaping in UTF-7.")
+
+(defconst utf7-imap-direct-encoding-chars
+ (concat utf7-direct-encoding-chars "+\\~")
+ "Character ranges which do not need escaping in the IMAP variant of UTF-7.")
+
+
+(eval-and-compile
+ (defun utf7-find-coding-system-without-bom (cs)
+ (and (fboundp 'find-coding-system)
+ (find-coding-system cs)
+ ;; Avoid versions with BOM.
+ (= 2 (length (encode-coding-string "a" cs)))
+ cs)))
+
+(defconst utf7-utf-16-coding-system
+ (or
+ ;; Emacs 22, Emacs 23
+ (utf7-find-coding-system-without-bom 'utf-16be)
+ ;;
+ (utf7-find-coding-system-without-bom 'utf-16-be)
+ ;; Mule-UCS
+ (utf7-find-coding-system-without-bom 'utf-16-be-no-signature))
+ "Coding system which encodes big endian UTF-16.")
+
+(defsubst utf7-imap-get-pad-length (len modulus)
"Return required length of padding for IMAP modified base64 fragment."
(mod (- len) modulus))
-(cond
- ((or (and (fboundp 'find-coding-system)
- (find-coding-system 'utf-7))
- (module-installed-p 'un-define))
- (defun utf7-fragment-decode (start end &optional imap)
- "Decode base64 encoded fragment from START to END of UTF-7 text in buffer.
-Use IMAP modification if IMAP is non-nil."
- (require 'un-define)
- (save-restriction
- (narrow-to-region start end)
- (goto-char (point-min))
- (insert "+")
- (when imap
- (goto-char start)
- (while (search-forward "," nil 'move-to-end) (replace-match "/")))
- (decode-coding-region (point-min) (point-max) 'utf-7)))
-
- (defun utf7-fragment-encode (start end &optional imap)
- "Encode text from START to END in buffer as UTF-7 escape fragment.
-Use IMAP modification if IMAP is non-nil."
- (require 'un-define)
- (let ((buffer (current-buffer))
- encoded-string)
- (setq encoded-string
- (with-temp-buffer
- (insert-buffer-substring buffer start end)
- (encode-coding-region (point-min)
- (point-max) 'utf-7)
- (goto-char (point-min))
- (when imap
- (skip-chars-forward "+")
- (delete-region (point-min) (point))
- (insert "&")
- (while (search-forward "/" nil t)
- (replace-match ",")))
- (skip-chars-forward "^= \t\n" (point-max))
- (delete-region (point) (point-max))
- (buffer-string)))
- (delete-region start end)
- (insert encoded-string))))
- ((and (featurep 'xemacs)
- (or (and (fboundp 'find-coding-system)
- (find-coding-system 'utf-8))
- (module-installed-p 'xemacs-ucs)))
- (defun utf7-fragment-decode (start end &optional imap)
- "Decode base64 encoded fragment from START to END of UTF-7 text in buffer.
-Use IMAP modification if IMAP is non-nil."
- (require 'xemacs-ucs)
- (save-restriction
- (narrow-to-region start end)
- (when imap
- (goto-char start)
- (while (search-forward "," nil 'move-to-end) (replace-match "/")))
- (goto-char (point-min))
- (insert "+")
- (as-binary-process
- (call-process-region (point-min) (point-max)
- utf7-utf7-to-utf8-program
- t (current-buffer)))
- (decode-coding-region (point-min) (point-max) 'utf-8)))
-
- (defun utf7-fragment-encode (start end &optional imap)
- "Decode base64 encoded fragment from START to END of UTF-7 text in buffer.
-Use IMAP modification if IMAP is non-nil."
- (require 'xemacs-ucs)
- (let ((buffer (current-buffer))
- encoded-string)
- (setq encoded-string
- (with-temp-buffer
- (insert-buffer-substring buffer start end)
- (save-excursion
- (goto-char (point-max))
- (insert "\n"))
- (encode-coding-region (point-min) (point-max) 'utf-8)
- (as-binary-process
- (call-process-region (point-min) (point-max)
- utf7-utf8-to-utf7-program
- t (current-buffer)))
- (goto-char (point-min))
- (when imap
- (skip-chars-forward "+")
- (delete-region (point-min) (point))
- (insert "&")
- (while (search-forward "/" nil t)
- (replace-match ",")))
- (goto-char (point-max))
- (delete-backward-char 1)
- (insert "-")
- (buffer-string)))
- (delete-region start end)
- (insert encoded-string))))
- (t
- (defun utf7-fragment-decode (start end &optional imap)
- "Encode text from START to END in buffer as UTF-7 escape fragment.
-Use IMAP modification if IMAP is non-nil."
- ;; Define as a null function.
- )
-
- (defun utf7-fragment-encode (start end &optional imap)
- "Encode text from START to END in buffer as UTF-7 escape fragment.
-Use IMAP modification if IMAP is non-nil."
- ;; Define as a null function.
- )))
-
-(defun utf7-encode-region (start end &optional imap)
- "Encode text in region as UTF-7.
-Use IMAP modification if IMAP is non-nil."
- (interactive "r")
- (save-restriction
- ;;(set-buffer-multibyte default-enable-multibyte-characters)
+(defun utf7-encode-internal (&optional for-imap)
+ "Encode text in (temporary) buffer as UTF-7.
+Use IMAP modification if FOR-IMAP is non-nil."
+ (let ((start (point-min))
+ (end (point-max)))
(narrow-to-region start end)
(goto-char start)
- (let ((esc-char (if imap ?& ?+))
- (direct-encoding-chars
- (if imap utf7-imap-direct-encoding-chars
- utf7-direct-encoding-chars)))
+ (let* ((esc-char (if for-imap ?& ?+))
+ (direct-encoding-chars
+ (if for-imap utf7-imap-direct-encoding-chars
+ utf7-direct-encoding-chars))
+ (not-direct-encoding-chars (concat "^" direct-encoding-chars)))
(while (not (eobp))
(skip-chars-forward direct-encoding-chars)
(unless (eobp)
+ (insert esc-char)
(let ((p (point))
(fc (following-char))
- (run-length
- (skip-chars-forward (concat "^" direct-encoding-chars))))
+ (run-length
+ (skip-chars-forward not-direct-encoding-chars)))
(if (and (= fc esc-char)
(= run-length 1)) ; Lone esc-char?
- (delete-backward-char 1) ; Now there's one too many
- (utf7-fragment-encode p (point) imap))))))))
-
-(defun utf7-decode-region (start end &optional imap)
- "Decode UTF-7 text in region.
-Use IMAP modification if IMAP is non-nil."
- (interactive "r")
- (save-excursion
+ (delete-char -1) ; Now there's one too many
+ (utf7-fragment-encode p (point) for-imap))
+ (insert "-")))))))
+
+(defun utf7-fragment-encode (start end &optional for-imap)
+ "Encode text from START to END in buffer as UTF-7 escape fragment.
+Use IMAP modification if FOR-IMAP is non-nil."
+ (let ((converter (utf7-get-u16char-converter 'to-utf-16))
+ (str (buffer-substring start end))
+ pm)
+ (when converter
+ (delete-region start end)
+ (goto-char start)
+ (insert
+ (with-temp-buffer
+ (insert str)
+ (funcall converter)
+ (set-buffer-multibyte nil)
+ (utf7-base64-encode-region (point-min) (point-max))
+ (goto-char (point-min))
+ (setq pm (point-max))
+ (when for-imap
+ (while (search-forward "/" nil t)
+ (replace-match ",")))
+ (skip-chars-forward "^= \t\n" pm)
+ (delete-region (point) pm)
+ (buffer-string))))))
+
+(defun utf7-decode-internal (&optional for-imap)
+ "Decode UTF-7 text in (temporary) buffer.
+Use IMAP modification if FOR-IMAP is non-nil."
+ (let ((start (point-min))
+ (end (point-max)))
(goto-char start)
- (let* ((esc-pattern (concat "^" (char-to-string (if imap ?& ?+))))
- (base64-chars (concat "A-Za-z0-9+"
- (char-to-string (if imap ?, ?/)))))
+ (let* ((esc-pattern (concat "^" (char-to-string (if for-imap ?& ?+))))
+ (base64-chars (concat "A-Za-z0-9+"
+ (char-to-string (if for-imap ?, ?/)))))
(while (not (eobp))
(skip-chars-forward esc-pattern)
(unless (eobp)
(delete-char 1))
(unless (= run-length 0) ; Encoded lone esc-char?
(save-excursion
- (utf7-fragment-decode p (point) imap)
+ (utf7-fragment-decode p (point) for-imap)
(goto-char p)
- (delete-backward-char 1)))))))
- ;;(set-buffer-multibyte default-enable-multibyte-characters)
- ))
+ (delete-char -1)))))))))
-(defun utf7-encode-string (string &optional imap)
- "Encode UTF-7 string. Use IMAP modification if IMAP is non-nil."
- (with-temp-buffer
- (insert string)
- (utf7-encode-region (point-min) (point-max) imap)
- (buffer-string)))
-
-(defun utf7-decode-string (string &optional imap)
- "Decode UTF-7 string. Use IMAP modification if IMAP is non-nil."
- (with-temp-buffer
- (insert string)
- (utf7-decode-region (point-min) (point-max) imap)
- (buffer-string)))
-
-;; For compatibility.
-(defalias 'utf7-decode 'utf7-decode-string)
-(defalias 'utf7-encode 'utf7-encode-string)
+(defun utf7-fragment-decode (start end &optional for-imap)
+ "Decode base64 encoded fragment from START to END of UTF-7 text in buffer.
+Use IMAP modification if FOR-IMAP is non-nil."
+ (save-restriction
+ (narrow-to-region start end)
+ (let ((converter (utf7-get-u16char-converter 'from-utf-16)))
+ (when converter
+ (when for-imap
+ (goto-char start)
+ (while (search-forward "," nil 'move-to-end) (replace-match "/")))
+ (let ((pl (utf7-imap-get-pad-length (- end start) 4)))
+ (insert (make-string pl ?=))
+ (utf7-base64-decode-region start (+ end pl)))
+ (funcall converter)))))
+
+(defun utf7-get-u16char-converter (which-way)
+ "Return a function to convert between UTF-16 and current character set."
+ (if utf7-utf-16-coding-system
+ (if (eq which-way 'to-utf-16)
+ (lambda ()
+ (encode-coding-region (point-min)(point-max)
+ utf7-utf-16-coding-system)
+ (set-buffer-multibyte nil)
+ (goto-char (point-min))
+ ;; Remove BOM (Big-endian UTF-16 FE FF) for Mule-UCS
+ (while (re-search-forward "\376\377" nil t)
+ (delete-region (match-beginning 0) (match-end 0))))
+ (lambda ()
+ (goto-char (point-min))
+ (decode-coding-region (point-min) (point-max)
+ utf7-utf-16-coding-system)))))
+
+(defun utf7-encode (string &optional for-imap)
+ "Encode UTF-7 STRING. Use IMAP modification if FOR-IMAP is non-nil."
+ (let ((default-enable-multibyte-characters t))
+ (with-temp-buffer
+ (insert string)
+ (utf7-encode-internal for-imap)
+ (buffer-string))))
+
+(defun utf7-decode (string &optional for-imap)
+ "Decode UTF-7 STRING. Use IMAP modification if FOR-IMAP is non-nil."
+ (let ((default-enable-multibyte-characters nil))
+ (with-temp-buffer
+ (insert string)
+ (utf7-decode-internal for-imap)
+ (set-buffer-multibyte t)
+ (buffer-string))))
+
+(defalias 'utf7-encode-string 'utf7-encode)
+(defalias 'utf7-decode-string 'utf7-decode)
(provide 'utf7)
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