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;;; rfc1843.el --- HZ (rfc1843) decoding
;; Copyright (c) 1998, 1999, 2000 Free Software Foundation, Inc.
;; Author: Shenghuo Zhu <zsh@cs.rochester.edu>
;; Keywords: news HZ HZ+ mail i18n
;; 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 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:
;; Usage:
;; (require 'rfc1843)
;; (rfc1843-gnus-setup)
;;
;; Test:
;; (rfc1843-decode-string "~{<:Ky2;S{#,NpJ)l6HK!#~}")
;;; Code:
(eval-when-compile (require 'cl))
(require 'mm-util)
(defvar rfc1843-word-regexp
"~\\({\\([\041-\167][\041-\176]\\| \\)+\\)\\(~}\\|$\\)")
(defvar rfc1843-word-regexp-strictly
"~\\({\\([\041-\167][\041-\176]\\)+\\)\\(~}\\|$\\)")
(defvar rfc1843-hzp-word-regexp
"~\\({\\([\041-\167][\041-\176]\\| \\)+\\|\
[<>]\\([\041-\175][\041-\176]\\| \\)+\\)\\(~}\\|$\\)")
(defvar rfc1843-hzp-word-regexp-strictly
"~\\({\\([\041-\167][\041-\176]\\)+\\|\
[<>]\\([\041-\175][\041-\176]\\)+\\)\\(~}\\|$\\)")
(defcustom rfc1843-decode-loosely nil
"Loosely check HZ encoding if non-nil.
When it is set non-nil, only buffers or strings with strictly
HZ-encoded are decoded."
:type 'boolean
:group 'gnus)
(defcustom rfc1843-decode-hzp t
"HZ+ decoding support if non-nil.
HZ+ specification (also known as HZP) is to provide a standardized
7-bit representation of mixed Big5, GB, and ASCII text for convenient
e-mail transmission, news posting, etc.
The document of HZ+ 0.78 specification can be found at
ftp://ftp.math.psu.edu/pub/simpson/chinese/hzp/hzp.doc"
:type 'boolean
:group 'gnus)
(defcustom rfc1843-newsgroups-regexp "chinese\\|hz"
"Regexp of newsgroups in which might be HZ encoded."
:type 'string
:group 'gnus)
(defun rfc1843-decode-region (from to)
"Decode HZ in the region between FROM and TO."
(interactive "r")
(let (str firstc)
(save-excursion
(goto-char from)
(if (or rfc1843-decode-loosely
(re-search-forward (if rfc1843-decode-hzp
rfc1843-hzp-word-regexp-strictly
rfc1843-word-regexp-strictly) to t))
(save-restriction
(narrow-to-region from to)
(goto-char (point-min))
(while (re-search-forward (if rfc1843-decode-hzp
rfc1843-hzp-word-regexp
rfc1843-word-regexp) (point-max) t)
;;; Text with extents may cause XEmacs crash
(setq str (buffer-substring-no-properties
(match-beginning 1)
(match-end 1)))
(setq firstc (aref str 0))
(insert (mm-decode-coding-string
(rfc1843-decode
(prog1
(substring str 1)
(delete-region (match-beginning 0) (match-end 0)))
firstc)
(if (eq firstc ?{) 'cn-gb-2312 'cn-big5))))
(goto-char (point-min))
(while (search-forward "~" (point-max) t)
(cond ((eq (char-after) ?\n)
(delete-char -1)
(delete-char 1))
((eq (char-after) ?~)
(delete-char 1)))))))))
(defun rfc1843-decode-string (string)
"Decode HZ STRING and return the results."
(let ((m (mm-multibyte-p)))
(with-temp-buffer
(when m
(mm-enable-multibyte))
(insert string)
(inline
(rfc1843-decode-region (point-min) (point-max)))
(buffer-string))))
(defun rfc1843-decode (word &optional firstc)
"Decode HZ WORD and return it."
(let ((i -1) (s (substring word 0)) v)
(if (or (not firstc) (eq firstc ?{))
(while (< (incf i) (length s))
(if (eq (setq v (aref s i)) ? ) nil
(aset s i (+ 128 v))))
(while (< (incf i) (length s))
(if (eq (setq v (aref s i)) ? ) nil
(setq v (+ (* 94 v) (aref s (1+ i)) -3135))
(aset s i (+ (/ v 157) (if (eq firstc ?<) 201 161)))
(setq v (% v 157))
(aset s (incf i) (+ v (if (< v 63) 64 98))))))
s))
(defun rfc1843-decode-article-body ()
"Decode HZ encoded text in the article body."
(if (string-match (concat "\\<\\(" rfc1843-newsgroups-regexp "\\)\\>")
(or gnus-newsgroup-name ""))
(save-excursion
(save-restriction
(message-narrow-to-head)
(let* ((inhibit-point-motion-hooks t)
(case-fold-search t)
(ct (message-fetch-field "Content-Type" t))
(ctl (and ct (ignore-errors
(mail-header-parse-content-type ct)))))
(if (and ctl (not (string-match "/" (car ctl))))
(setq ctl nil))
(goto-char (point-max))
(widen)
(forward-line 1)
(narrow-to-region (point) (point-max))
(when (or (not ctl)
(equal (car ctl) "text/plain"))
(rfc1843-decode-region (point) (point-max))))))))
(defvar rfc1843-old-gnus-decode-header-function nil)
(defvar gnus-decode-header-methods)
(defvar gnus-decode-encoded-word-methods)
(defun rfc1843-gnus-setup ()
"Setup HZ decoding for Gnus."
(require 'gnus-art)
(require 'gnus-sum)
(add-hook 'gnus-article-decode-hook 'rfc1843-decode-article-body t)
(setq gnus-decode-encoded-word-function
'gnus-multi-decode-encoded-word-string
gnus-decode-header-function
'gnus-multi-decode-header
gnus-decode-encoded-word-methods
(nconc gnus-decode-encoded-word-methods
(list
(cons (concat "\\<\\(" rfc1843-newsgroups-regexp "\\)\\>")
'rfc1843-decode-string)))
gnus-decode-header-methods
(nconc gnus-decode-header-methods
(list
(cons (concat "\\<\\(" rfc1843-newsgroups-regexp "\\)\\>")
'rfc1843-decode-region)))))
(provide 'rfc1843)
;;; rfc1843.el ends here
|
