;;; emu-x21.el --- emu module for XEmacs 21 file-coding (non-mule)

;; Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.

;; Author: MORIOKA Tomohiko <morioka@jaist.ac.jp>
;; Version: $Id: emu-e19.el,v 7.44 1997/02/13 08:15:39 morioka Exp $
;; Keywords: emulation, compatibility, mule, Latin-1

;; This file is part of emu.

;; 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:

;;; @ version and variant specific features
;;;

(require 'emu-xemacs)

;;; @ character set
;;; xemacs 21 with file coding has coding stuff but not charset stuff.

(defconst charset-ascii 0 "Character set of ASCII")
(defconst charset-latin-iso8859-1 129 "Character set of ISO-8859-1")

(defun charset-description (charset)
  "Return description of CHARSET. [emu-x21.el]"
  (if (< charset 128)
      (documentation-property 'charset-ascii 'variable-documentation)
    (documentation-property 'charset-latin-iso8859-1 'variable-documentation)
    ))

(defun charset-registry (charset)
  "Return registry name of CHARSET. [emu-x21.el]"
  (if (< charset 128)
      "ASCII"
    "ISO8859-1"))

(defun charset-columns (charset)
  "Return number of columns a CHARSET occupies when displayed.
\[emu-x21.el]"
  1)

(defun charset-direction (charset)
  "Return the direction of a character of CHARSET by
  0 (left-to-right) or 1 (right-to-left). [emu-x21.el]"
  0)

(defun find-charset-string (str)
  "Return a list of charsets in the string.
\[emu-x21.el; Mule emulating function]"
  (if (string-match "[\200-\377]" str)
      (list charset-latin-iso8859-1)
    ))

(defalias 'find-non-ascii-charset-string 'find-charset-string)

(defun find-charset-region (start end)
  "Return a list of charsets in the region between START and END.
\[emu-x21.el; Mule emulating function]"
  (if (save-excursion
	(save-restriction
	  (narrow-to-region start end)
	  (goto-char start)
	  (re-search-forward "[\200-\377]" nil t)
	  ))
      (list charset-latin-iso8859-1)
    ))

(defalias 'find-non-ascii-charset-region 'find-charset-region)


;;; @ coding-system
;;;

(defconst *internal* nil)
(defconst *ctext* nil)
(defconst *noconv* nil)

(defmacro as-binary-process (&rest body)
  `(let (selective-display	; Disable ^M to nl translation.
	 (coding-system-for-read  'binary)
	 (coding-system-for-write 'binary))
     ,@body))

(defmacro as-binary-input-file (&rest body)
  `(let ((coding-system-for-read 'binary))
     ,@body))

(defmacro as-binary-output-file (&rest body)
  `(let ((coding-system-for-write 'binary))
     ,@body))

;;; @@ for old MULE emulation
;;;

(defun code-convert-string (str ic oc)
  "Convert code in STRING from SOURCE code to TARGET code,
On successful converion, returns the result string,
else returns nil. [emu-e19.el; old MULE emulating function]"
  str)

(defun code-convert-region (beg end ic oc)
  "Convert code of the text between BEGIN and END from SOURCE
to TARGET. On successful conversion returns t,
else returns nil. [emu-e19.el; old MULE emulating function]"
  t)


;;; @ binary access
;;;

(defun insert-binary-file-contents-literally
  (filename &optional visit beg end replace)
  "Like `insert-file-contents-literally', q.v., but don't code conversion.
A buffer may be modified in several ways after reading into the buffer due
to advanced Emacs features, such as file-name-handlers, format decoding,
find-file-hooks, etc.
  This function ensures that none of these modifications will take place."
  (let ((coding-system-for-read 'binary))
    (insert-file-contents-literally filename visit beg end replace)
    ))

;;; @ MIME charset
;;;

(defvar charsets-mime-charset-alist
  (list (cons (list charset-ascii) 'us-ascii)))

(defvar default-mime-charset 'iso-8859-1)

(defun mime-charset-to-coding-system (charset)
  (if (stringp charset)
      (setq charset (intern (downcase charset)))
    )
  (and (memq charset (list 'us-ascii default-mime-charset))
       charset)
  )

(defun detect-mime-charset-region (start end)
  "Return MIME charset for region between START and END.
\[emu-x21.el]"
  (if (save-excursion
	(save-restriction
	  (narrow-to-region start end)
	  (goto-char start)
	  (re-search-forward "[\200-\377]" nil t)
	  ))
      default-mime-charset
    'us-ascii))

(defun encode-mime-charset-region (start end charset)
  "Encode the text between START and END as MIME CHARSET.
\[emu-x21.el]"
  )

(defun decode-mime-charset-region (start end charset)
  "Decode the text between START and END as MIME CHARSET.
\[emu-x21.el]"
  )

(defun encode-mime-charset-string (string charset)
  "Encode the STRING as MIME CHARSET. [emu-x21.el]"
  string)

(defun decode-mime-charset-string (string charset)
  "Decode the STRING as MIME CHARSET. [emu-x21.el]"
  string)


;;; @ character
;;;

(defun char-charset (chr)
  "Return the character set of char CHR.
\[emu-e19.el; XEmacs 20 emulating function]"
  (if (< chr 128)
      charset-ascii
    charset-latin-iso8859-1))

(defun char-bytes (char)
  "Return number of bytes a character in CHAR occupies in a buffer.
\[emu-e19.el; MULE emulating function]"
  1)

(defalias 'char-length 'char-bytes)

(defun char-columns (character)
  "Return number of columns a CHARACTER occupies when displayed.
\[emu-x21.el]"
  1)

;;; @@ for old MULE emulation
;;;

(defalias 'char-width 'char-columns)

(defalias 'char-leading-char 'char-charset)


;;; @ string
;;;

(defalias 'string-columns 'length)

(defun string-to-char-list (str)
  (mapcar (function identity) str)
  )

(defalias 'string-to-int-list 'string-to-char-list)

(defalias 'sref 'aref)

(defun truncate-string (str width &optional start-column)
  "Truncate STR to fit in WIDTH columns.
Optional non-nil arg START-COLUMN specifies the starting column.
\[emu-x21.el; MULE 2.3 emulating function]"
  (or start-column
      (setq start-column 0))
  (substring str start-column width)
  )

;;; @@ for old MULE emulation
;;;

(defalias 'string-width 'length)


;;; @ end
;;;

(provide 'emu-x21)

;;; emu-x21.el ends here