;;; mule-coding.el --- Coding-system functions for Mule.

;; Copyright (C) 1995 Electrotechnical Laboratory, JAPAN.
;; Licensed to the Free Software Foundation.
;; Copyright (C) 1995 Amdahl Corporation.
;; Copyright (C) 1995 Sun Microsystems.
;; Copyright (C) 1997 MORIOKA Tomohiko

;; This file is part of XEmacs.

;; XEmacs 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.

;; XEmacs 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 XEmacs; see the file COPYING.  If not, write to the 
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;;; split off of mule.el.

;;; Code:

(defalias 'check-coding-system 'get-coding-system)

(defun modify-coding-system-alist (target-type regexp coding-system)
  "Modify one of look up tables for finding a coding system on I/O operation.
There are three of such tables, `file-coding-system-alist',
`process-coding-system-alist', and `network-coding-system-alist'.

TARGET-TYPE specifies which of them to modify.
If it is `file', it affects `file-coding-system-alist' (which see).
If it is `process', it affects `process-coding-system-alist' (which see).
If it is `network', it affects `network-codign-system-alist' (which see).

REGEXP is a regular expression matching a target of I/O operation.
The target is a file name if TARGET-TYPE is `file', a program name if
TARGET-TYPE is `process', or a network service name or a port number
to connect to if TARGET-TYPE is `network'.

CODING-SYSTEM is a coding system to perform code conversion on the I/O
operation, or a cons cell (DECODING . ENCODING) specifying the coding systems
for decoding and encoding respectively,
or a function symbol which, when called, returns such a cons cell."
  (or (memq target-type '(file process network))
      (error "Invalid target type: %s" target-type))
  (or (stringp regexp)
      (and (eq target-type 'network) (integerp regexp))
      (error "Invalid regular expression: %s" regexp))
  (if (symbolp coding-system)
      (if (not (fboundp coding-system))
	  (progn
	    (check-coding-system coding-system)
	    (setq coding-system (cons coding-system coding-system))))
    (check-coding-system (car coding-system))
    (check-coding-system (cdr coding-system)))
  (cond ((eq target-type 'file)
	 (let ((slot (assoc regexp file-coding-system-alist)))
	   (if slot
	       (setcdr slot coding-system)
	     (setq file-coding-system-alist
		   (cons (cons regexp coding-system)
			 file-coding-system-alist)))))
	((eq target-type 'process)
	 (let ((slot (assoc regexp process-coding-system-alist)))
	   (if slot
	       (setcdr slot coding-system)
	     (setq process-coding-system-alist
		   (cons (cons regexp coding-system)
			 process-coding-system-alist)))))
	(t
	 (let ((slot (assoc regexp network-coding-system-alist)))
	   (if slot
	       (setcdr slot coding-system)
	     (setq network-coding-system-alist
		   (cons (cons regexp coding-system)
			 network-coding-system-alist)))))))

(defsubst keyboard-coding-system ()
  "Return coding-system of what is sent from terminal keyboard."
  keyboard-coding-system)

(defun set-keyboard-coding-system (coding-system)
  "Set the coding system used for TTY keyboard input. Currently broken."
  (interactive "zkeyboard-coding-system: ")
  (get-coding-system coding-system) ; correctness check
  (setq keyboard-coding-system coding-system)
  (redraw-modeline t))

(defsubst terminal-coding-system ()
  "Return coding-system of your terminal."
  terminal-coding-system)

(defun set-terminal-coding-system (coding-system)
  "Set the coding system used for TTY display output. Currently broken."
  (interactive "zterminal-coding-system: ")
  (get-coding-system coding-system) ; correctness check
  (setq terminal-coding-system coding-system)
  (redraw-modeline t))

(defun set-pathname-coding-system (coding-system)
  "Set the coding system used for file system path names."
  (interactive "zPathname-coding-system: ")
  (get-coding-system coding-system) ; correctness check
  (setq file-name-coding-system coding-system))

(defun what-coding-system (start end &optional arg)
  "Show the encoding of text in the region.
This function is meant to be called interactively;
from a Lisp program, use `detect-coding-region' instead."
  (interactive "r\nP")
  (princ (detect-coding-region start end)))

(defun decode-coding-string (str coding-system)
  "Decode the string STR which is encoded in CODING-SYSTEM.
Does not modify STR.  Returns the decoded string on successful conversion."
  (with-string-as-buffer-contents
   str (decode-coding-region (point-min) (point-max) coding-system)))

(defun encode-coding-string (str coding-system)
  "Encode the string STR using CODING-SYSTEM.
Does not modify STR.  Returns the encoded string on successful conversion."
  (with-string-as-buffer-contents
   str (encode-coding-region (point-min) (point-max) coding-system)))


;;;; Coding system accessors

(defun coding-system-mnemonic (coding-system)
  "Return the 'mnemonic property of CODING-SYSTEM."
  (coding-system-property coding-system 'mnemonic))

(defalias 'coding-system-docstring 'coding-system-doc-string)

(defun coding-system-eol-type (coding-system)
  "Return the 'eol-type property of CODING-SYSTEM."
  (coding-system-property coding-system 'eol-type))

(defun coding-system-eol-lf (coding-system)
  "Return the 'eol-lf property of CODING-SYSTEM."
  (coding-system-property coding-system 'eol-lf))

(defun coding-system-eol-crlf (coding-system)
  "Return the 'eol-crlf property of CODING-SYSTEM."
  (coding-system-property coding-system 'eol-crlf))

(defun coding-system-eol-cr (coding-system)
  "Return the 'eol-cr property of CODING-SYSTEM."
  (coding-system-property coding-system 'eol-cr))

(defun coding-system-post-read-conversion (coding-system)
  "Return the 'post-read-conversion property of CODING-SYSTEM."
  (coding-system-property coding-system 'post-read-conversion))

(defun coding-system-pre-write-conversion (coding-system)
  "Return the 'pre-write-conversion property of CODING-SYSTEM."
  (coding-system-property coding-system 'pre-write-conversion))

(defun coding-system-force-on-output (coding-system register)
  "Return the 'force-on-output property of CODING-SYSTEM for the specified REGISTER."
  (unless (integerp register)
    (signal 'wrong-type-argument (list 'integerp register)))
  (coding-system-property
   coding-system
   (case register
     (0 'force-g0-on-output)
     (1 'force-g1-on-output)
     (2 'force-g2-on-output)
     (3 'force-g3-on-output)
     (t (signal 'args-out-of-range (list register 0 3))))))

(defun coding-system-short (coding-system)
  "Return the 'short property of CODING-SYSTEM."
  (coding-system-property coding-system 'short))

(defun coding-system-no-ascii-eol (coding-system)
  "Return the 'no-ascii-eol property of CODING-SYSTEM."
  (coding-system-property coding-system 'no-ascii-eol))

(defun coding-system-no-ascii-cntl (coding-system)
  "Return the 'no-ascii-cntl property of CODING-SYSTEM."
  (coding-system-property coding-system 'no-ascii-cntl))

(defun coding-system-seven (coding-system)
  "Return the 'seven property of CODING-SYSTEM."
  (coding-system-property coding-system 'seven))

(defun coding-system-lock-shift (coding-system)
  "Return the 'lock-shift property of CODING-SYSTEM."
  (coding-system-property coding-system 'lock-shift))

;;(defun coding-system-use-japanese-jisx0201-roman (coding-system)
;;  "Return the 'use-japanese-jisx0201-roman property of CODING-SYSTEM."
;;  (coding-system-property coding-system 'use-japanese-jisx0201-roman))

;;(defun coding-system-use-japanese-jisx0208-1978 (coding-system)
;;  "Return the 'use-japanese-jisx0208-1978 property of CODING-SYSTEM."
;;  (coding-system-property coding-system 'use-japanese-jisx0208-2978))

(defun coding-system-no-iso6429 (coding-system)
  "Return the 'no-iso6429 property of CODING-SYSTEM."
  (coding-system-property coding-system 'no-iso6429))

(defun coding-system-ccl-encode (coding-system)
  "Return the CCL 'encode property of CODING-SYSTEM."
  (coding-system-property coding-system 'encode))

(defun coding-system-ccl-decode (coding-system)
  "Return the CCL 'decode property of CODING-SYSTEM."
  (coding-system-property coding-system 'decode))


;;;; Definitions of predefined coding systems

(make-coding-system
 'undecided 'undecided
 "Automatic conversion."
 '(mnemonic "Auto"))

;; compatibility for old XEmacsen (don't use it)
(copy-coding-system 'undecided 'automatic-conversion)

(copy-coding-system 'no-conversion 'raw-text)

(make-coding-system
 'ctext 'iso2022
 "Coding-system used in X as Compound Text Encoding."
 '(charset-g0 ascii
   charset-g1 latin-iso8859-1
   eol-type lf
   mnemonic "CText"
   ))

;;; iso-8859-1 and ctext are aliases.

(copy-coding-system 'ctext 'iso-8859-1)

(make-coding-system
 'iso-2022-8bit-ss2 'iso2022
 "ISO-2022 coding system using SS2 for 96-charset in 8-bit code."
 '(charset-g0 ascii
   charset-g1 latin-iso8859-1
   charset-g2 t ;; unspecified but can be used later.
   short t
   mnemonic "ISO8/SS"
   ))

(make-coding-system
 'iso-2022-7bit-ss2 'iso2022
 "ISO-2022 coding system using SS2 for 96-charset in 7-bit code."
 '(charset-g0 ascii
   charset-g2 t ;; unspecified but can be used later.
   seven t
   short t
   mnemonic "ISO7/SS"
   ))

(copy-coding-system 'iso-2022-7bit-ss2 'iso-2022-jp-2)

(make-coding-system
 'iso-2022-7bit 'iso2022
 "ISO 2022 based 7-bit encoding using only G0"
 '(charset-g0 ascii
   seven t
   short t
   mnemonic "ISO7"))

;; compatibility for old XEmacsen
(copy-coding-system 'iso-2022-7bit 'iso-2022-7)

(make-coding-system
 'iso-2022-8 'iso2022
 "ISO-2022 eight-bit coding system.  No single-shift or locking-shift."
 '(charset-g0 ascii
   charset-g1 latin-iso8859-1
   short t
   mnemonic "ISO8"
   ))

(make-coding-system
 'escape-quoted 'iso2022
 "ISO-2022 eight-bit coding system with escape quoting; used for .ELC files."
 '(charset-g0 ascii
   charset-g1 latin-iso8859-1
   eol-type lf
   escape-quoted t
   mnemonic "ESC/Quot"
   ))

(make-coding-system
 'iso-2022-lock 'iso2022
 "ISO-2022 coding system using Locking-Shift for 96-charset."
 '(charset-g0 ascii
   charset-g1 t ;; unspecified but can be used later.
   seven t
   lock-shift t
   mnemonic "ISO7/Lock"
   ))

;; initialize the coding categories to something semi-reasonable
;; so that the remaining Lisp files can contain extended characters.
;; (They will be in ISO-7 format)

(set-coding-priority-list '(iso-8-2 iso-8-designate iso-8-1
			    iso-7 iso-lock-shift no-conversion))

(set-coding-category-system 'iso-7 'iso-2022-7)
(set-coding-category-system 'iso-8-designate 'ctext)
(set-coding-category-system 'iso-8-1 'ctext)
(set-coding-category-system 'iso-lock-shift 'iso-2022-lock)
(set-coding-category-system 'no-conversion 'no-conversion)

(make-compatible-variable 'enable-multibyte-characters "Unimplemented")

(define-obsolete-variable-alias
  'pathname-coding-system 'file-name-coding-system)

;;; mule-coding.el ends here