mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-27 07:37:33 +00:00
133 lines
4.1 KiB
EmacsLisp
133 lines
4.1 KiB
EmacsLisp
;;; rfc1843.el --- HZ (RFC 1843) decoding -*- lexical-binding:t -*-
|
|
|
|
;; Copyright (C) 1998-2023 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 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 <https://www.gnu.org/licenses/>.
|
|
|
|
;;; Commentary:
|
|
|
|
;; HZ (RFC 1843) decoding. HZ is a data format for exchanging files
|
|
;; of arbitrarily mixed Chinese and ASCII characters.
|
|
;;
|
|
;; Test:
|
|
;; (rfc1843-decode-string "~{<:Ky2;S{#,NpJ)l6HK!#~}")
|
|
|
|
;;; Code:
|
|
|
|
(eval-when-compile (require 'cl-lib))
|
|
|
|
(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 'mime)
|
|
|
|
(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."
|
|
:type 'boolean
|
|
:group 'mime)
|
|
|
|
(defcustom rfc1843-newsgroups-regexp "chinese\\|hz"
|
|
"Regexp of newsgroups in which might be HZ encoded."
|
|
:type 'regexp
|
|
:group 'mime)
|
|
|
|
(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)
|
|
(setq str (buffer-substring-no-properties
|
|
(match-beginning 1)
|
|
(match-end 1)))
|
|
(setq firstc (aref str 0))
|
|
(insert (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 enable-multibyte-characters))
|
|
(with-temp-buffer
|
|
(when m
|
|
(set-buffer-multibyte 'to))
|
|
(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 (< (cl-incf i) (length s))
|
|
(if (eq (setq v (aref s i)) ? ) nil
|
|
(aset s i (+ 128 v))))
|
|
(while (< (cl-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 (cl-incf i) (+ v (if (< v 63) 64 98))))))
|
|
s))
|
|
|
|
(provide 'rfc1843)
|
|
|
|
;;; rfc1843.el ends here
|