/usr/share/emacs/site-lisp/wl/elmo/utf7.el is in wl-beta 2.15.9+0.20171209-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 | ;;; 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@acm.org>
;; Maintainer: bugs@gnus.org
;; Keywords: mail
;; 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)
;; 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; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; 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.
;; 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))
(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))
(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 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 not-direct-encoding-chars)))
(if (and (= fc esc-char)
(= run-length 1)) ; Lone esc-char?
(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 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)
(forward-char)
(let ((p (point))
(run-length (skip-chars-forward base64-chars)))
(when (and (not (eobp)) (= (following-char) ?-))
(delete-char 1))
(unless (= run-length 0) ; Encoded lone esc-char?
(save-excursion
(utf7-fragment-decode p (point) for-imap)
(goto-char p)
(delete-char -1)))))))))
(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)
;;; utf7.el ends here
|