;;; mcs-om.el --- MIME charset implementation for Mule 1.* and Mule 2.*

;; Copyright (C) 1995,1996,1997,1998 MORIOKA Tomohiko

;; Author: MORIOKA Tomohiko <morioka@jaist.ac.jp>
;; Keywords: emulation, compatibility, Mule

;; This file is part of APEL (A Portable Emacs Library).

;; This program 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.

;; This program 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.

;;; Code:

(require 'poem)

(defun encode-mime-charset-region (start end charset)
  "Encode the text between START and END as MIME CHARSET."
  (let ((cs (mime-charset-to-coding-system charset)))
    (if cs
	(code-convert start end *internal* cs)
      )))

(defun decode-mime-charset-region (start end charset &optional lbt)
  "Decode the text between START and END as MIME CHARSET."
  (let ((cs (mime-charset-to-coding-system charset lbt))
	newline)
    (if cs
	(code-convert start end cs *internal*)
      (if (and lbt (setq cs (mime-charset-to-coding-system charset)))
	  (progn
	    (if (setq newline (cdr (assq lbt '((CRLF . "\r\n") (CR . "\r")))))
		(save-excursion
		  (save-restriction
		    (narrow-to-region start end)
		    (goto-char (point-min))
		    (while (search-forward newline nil t)
		      (replace-match "\n")))
		  (code-convert (point-min) (point-max) cs *internal*))
	      (code-convert start end cs *internal*)))))))

(defun encode-mime-charset-string (string charset)
  "Encode the STRING as MIME CHARSET."
  (let ((cs (mime-charset-to-coding-system charset)))
    (if cs
	(code-convert-string string *internal* cs)
      string)))

(defun decode-mime-charset-string (string charset &optional lbt)
  "Decode the STRING which is encoded in MIME CHARSET."
  (let ((cs (mime-charset-to-coding-system charset lbt))
	newline)
    (if cs
	(decode-coding-string string cs)
      (if (and lbt (setq cs (mime-charset-to-coding-system charset)))
	  (progn
	    (if (setq newline (cdr (assq lbt '((CRLF . "\r\n") (CR . "\r")))))
		(with-temp-buffer
		 (insert string)
		 (goto-char (point-min))
		 (while (search-forward newline nil t)
		   (replace-match "\n"))
		 (code-convert (point-min) (point-max) cs *internal*)
		 (buffer-string))
	      (decode-coding-string string cs)))
	string))))

(cond
 (running-emacs-19_29-or-later
  ;; for MULE 2.3 based on Emacs 19.34.
  (defun write-region-as-mime-charset (charset start end filename
					       &optional append visit lockname)
    "Like `write-region', q.v., but code-convert by MIME CHARSET."
    (let ((file-coding-system
	   (or (mime-charset-to-coding-system charset)
	       *noconv*)))
      (write-region start end filename append visit lockname)))
  )
 (t
  ;; for MULE 2.3 based on Emacs 19.28.
  (defun write-region-as-mime-charset (charset start end filename
					       &optional append visit lockname)
    "Like `write-region', q.v., but code-convert by MIME CHARSET."
    (let ((file-coding-system
	   (or (mime-charset-to-coding-system charset)
	       *noconv*)))
      (write-region start end filename append visit)))
  ))


;;; @ to coding-system
;;;

(require 'cyrillic)

(defvar mime-charset-coding-system-alist
  '((iso-8859-1      . *ctext*)
    (x-ctext         . *ctext*)
    (gb2312          . *euc-china*)
    (koi8-r          . *koi8*)
    (iso-2022-jp-2   . *iso-2022-ss2-7*)
    (x-iso-2022-jp-2 . *iso-2022-ss2-7*)
    (shift_jis       . *sjis*)
    (x-shiftjis      . *sjis*)
    ))

(defsubst mime-charset-to-coding-system (charset &optional lbt)
  (if (stringp charset)
      (setq charset (intern (downcase charset)))
    )
  (setq charset (or (cdr (assq charset mime-charset-coding-system-alist))
		    (intern (concat "*" (symbol-name charset) "*"))))
  (if lbt
      (setq charset (intern (format "%s%s" charset
				    (cond ((eq lbt 'CRLF) 'dos)
					  ((eq lbt 'LF) 'unix)
					  ((eq lbt 'CR) 'mac)
					  (t lbt)))))
    )
  (if (coding-system-p charset)
      charset
    ))


;;; @ detection
;;;

(defvar charsets-mime-charset-alist
  (let ((alist
	 '(((lc-ascii)					. us-ascii)
	   ((lc-ascii lc-ltn1)				. iso-8859-1)
	   ((lc-ascii lc-ltn2)				. iso-8859-2)
	   ((lc-ascii lc-ltn3)				. iso-8859-3)
	   ((lc-ascii lc-ltn4)				. iso-8859-4)
;;;	   ((lc-ascii lc-crl)				. iso-8859-5)
	   ((lc-ascii lc-crl)				. koi8-r)
	   ((lc-ascii lc-arb)				. iso-8859-6)
	   ((lc-ascii lc-grk)				. iso-8859-7)
	   ((lc-ascii lc-hbw)				. iso-8859-8)
	   ((lc-ascii lc-ltn5)				. iso-8859-9)
	   ((lc-ascii lc-roman lc-jpold lc-jp)		. iso-2022-jp)
	   ((lc-ascii lc-kr)				. euc-kr)
	   ((lc-ascii lc-cn)				. gb2312)
	   ((lc-ascii lc-big5-1 lc-big5-2)		. big5)
	   ((lc-ascii lc-roman lc-ltn1 lc-grk
		      lc-jpold lc-cn lc-jp lc-kr
		      lc-jp2)				. iso-2022-jp-2)
	   ((lc-ascii lc-roman lc-ltn1 lc-grk
		      lc-jpold lc-cn lc-jp lc-kr lc-jp2
		      lc-cns1 lc-cns2)			. iso-2022-int-1)
	   ((lc-ascii lc-roman
		      lc-ltn1 lc-ltn2 lc-crl lc-grk
		      lc-jpold lc-cn lc-jp lc-kr lc-jp2
		      lc-cns1 lc-cns2 lc-cns3 lc-cns4
		      lc-cns5 lc-cns6 lc-cns7)		. iso-2022-int-1)
	   ))
	dest)
    (while alist
      (catch 'not-found
	(let ((pair (car alist)))
	  (setq dest
		(append dest
			(list
			 (cons (mapcar (function
					(lambda (cs)
					  (if (boundp cs)
					      (symbol-value cs)
					    (throw 'not-found nil)
					    )))
				       (car pair))
			       (cdr pair)))))))
      (setq alist (cdr alist)))
    dest))

(defvar default-mime-charset 'x-ctext
  "Default value of MIME-charset.
It is used when MIME-charset is not specified.
It must be symbol.")

(defun detect-mime-charset-region (start end)
  "Return MIME charset for region between START and END."
  (charsets-to-mime-charset
   (cons lc-ascii (find-charset-region start end))))


;;; @ end
;;;

(provide 'mcs-om)

;;; mcs-om.el ends here