;;; thai-xtis.el --- Support for Thai (XTIS) -*- coding: iso-2022-7bit; -*-

;; Copyright (C) 1999 Electrotechnical Laboratory, JAPAN.
;; Licensed to the Free Software Foundation.

;; Author: TAKAHASHI Naoto <ntakahas@etl.go.jp>
;;         MORIOKA Tomohiko <tomo@etl.go.jp>
;; Created: 1998-03-27 for Emacs-20.3 by TAKAHASHI Naoto
;;	    1999-03-29 imported and modified for XEmacs	by MORIOKA Tomohiko

;; Keywords: mule, multilingual, Thai, XTIS

;; 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:

;; For Thai, the pre-composed character set proposed by
;; Virach Sornlertlamvanich <virach@links.nectec.or.th> is supported.

;;; Code:

(make-charset 'thai-xtis "Precomposed Thai (XTIS by Virach)."
	      '(registries ["xtis-0"]
		dimension 2
		columns 1
		chars 94
		final ??
		graphic 0))

(define-category ?x "Precomposed Thai character.")
(modify-category-entry 'thai-xtis ?x)

(when (featurep 'xemacs)
  (let ((deflist	'(;; chars	syntax
			  ("$(?!0(B-$(?NxP0R0S0`0(B-$(?e0(B"	"w")
			  ("$(?p0(B-$(?y0(B"	"w")
			  ("$(?O0f0_0o0z0{0(B"	"_")
			  ))
	elm chars len syntax to ch i)
    (while deflist
      (setq elm (car deflist))
      (setq chars (car elm)
	    len (length chars)
	    syntax (nth 1 elm)
	    i 0)
      (while (< i len)
	(if (= (aref chars i) ?-)
	    (setq i (1+ i)
		  to (nth 1 (split-char (aref chars i))))
	  (setq ch (nth 1 (split-char (aref chars i)))
		to ch))
	(while (<= ch to)
	  (modify-syntax-entry (vector 'thai-xtis ch) syntax)
	  (setq ch (1+ ch)))
	(setq i (1+ i)))
      (setq deflist (cdr deflist))))

  (put-charset-property 'thai-xtis 'preferred-coding-system 'tis-620)
  )

;; This is the ccl-decode-thai-xtis automaton.
;;
;; "WRITE x y" == (insert (make-char 'thai-xtis x y))
;; "write x" == (insert x)
;; rx' == (tis620-to-thai-xtis-second-byte-bitpattern rx)
;; r3 == "no vower nor tone"
;; r4 == (charset-id 'thai-xtis)
;; 
;;          |               input (= r0)
;;   state  |--------------------------------------------
;;          |  consonant  |    vowel    |    tone
;; ---------+-------------+-------------+----------------
;;  r1 == 0 | r1 = r0     | WRITE r0,r3 | WRITE r0,r3
;;  r2 == 0 |             |             |
;; ---------+-------------+-------------+----------------
;;  r1 == C | WRITE r1,r3 | r2 = r0'    | WRITE r1,r3|r0'
;;  r2 == 0 | r1 = r0     |             | r1 = 0
;; ---------+-------------+-------------+----------------
;;  r1 == C | WRITE r1,r2 | WRITE r1,r2 | WRITE r1,r2|r0'
;;  r2 == V | r1 = r0     | WRITE r0,r3 | r1 = r2 = 0
;;          | r2 = 0      | r1 = r2 = 0 |
;; 
;; 
;;          |               input (= r0) 
;;   state  |-----------------------------------------
;;          |    symbol   |    ASCII    |     EOF
;; ---------+-------------+-------------+-------------
;;  r1 == 0 | WRITE r0,r3 | write r0    |
;;  r2 == 0 |             |             |
;; ---------+-------------+-------------+-------------
;;  r1 == C | WRITE r1,r3 | WRITE r1,r3 | WRITE r1,r3
;;  r2 == 0 | WRITE r0,r3 | write r0    |
;;          | r1 = 0      | r1 = 0      |
;; ---------+-------------+-------------+-------------
;;  r1 == C | WRITE r1,r2 | WRITE r1,r2 | WRITE r1,r2
;;  r2 == V | WRITE r0,r3 | write r0    |
;;          | r1 = r2 = 0 | r1 = r2 = 0 |


(eval-and-compile

;; input  : r5 = 1st byte, r6 = 2nd byte
;; Their values will be destroyed.
(define-ccl-program ccl-thai-xtis-write
  '(0
    ((r5 = ((r5 & #x7F) << 7))
     (r6 = ((r6 & #x7F) | r5))
     (write-multibyte-character r4 r6))))

(define-ccl-program ccl-thai-xtis-consonant
  '(0
    (if (r1 == 0)
	(r1 = r0)
      (if (r2 == 0)
	  ((r5 = r1) (r6 = r3) (call ccl-thai-xtis-write)
	   (r1 = r0))
	((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write)
	 (r1 = r0)
	 (r2 = 0))))))

(define-ccl-program ccl-thai-xtis-vowel
  '(0
    ((if (r1 == 0)
	 ((r5 = r0) (r6 = r3) (call ccl-thai-xtis-write))
       ((if (r2 == 0)
	    (r2 = ((r0 - 204) << 3))
	  ((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write)
	   (r5 = r0) (r6 = r3) (call ccl-thai-xtis-write)
	   (r1 = 0)
	   (r2 = 0))))))))

(define-ccl-program ccl-thai-xtis-vowel-d1
  '(0
    ((if (r1 == 0)
	 ((r5 = r0) (r6 = r3) (call ccl-thai-xtis-write))
       ((if (r2 == 0)
	    (r2 = #x38)
	  ((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write)
	   (r5 = r0) (r6 = r3) (call ccl-thai-xtis-write)
	   (r1 = 0)
	   (r2 = 0))))))))

(define-ccl-program ccl-thai-xtis-vowel-ee
  '(0
    ((if (r1 == 0)
	 ((r5 = r0) (r6 = r3) (call ccl-thai-xtis-write))
       ((if (r2 == 0)
	    (r2 = #x78)
	  ((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write)
	   (r5 = r0) (r6 = r3) (call ccl-thai-xtis-write)
	   (r1 = 0)
	   (r2 = 0))))))))

(define-ccl-program ccl-thai-xtis-tone
  '(0
    (if (r1 == 0)
	((r5 = r0) (r6 = r3) (call ccl-thai-xtis-write))
      (if (r2 == 0)
	  ((r5 = r1) (r6 = ((r0 - #xE6) | r3)) (call ccl-thai-xtis-write)
	   (r1 = 0))
	((r5 = r1) (r6 = ((r0 - #xE6) | r2)) (call ccl-thai-xtis-write)
	 (r1 = 0)
	 (r2 = 0))))))

(define-ccl-program ccl-thai-xtis-symbol
  '(0
    (if (r1 == 0)
	((r5 = r0) (r6 = r3) (call ccl-thai-xtis-write))
      (if (r2 == 0)
	  ((r5 = r1) (r6 = r3) (call ccl-thai-xtis-write)
	   (r5 = r0) (r6 = r3) (call ccl-thai-xtis-write)
	   (r1 = 0))
	((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write)
	 (r5 = r0) (r6 = r3) (call ccl-thai-xtis-write)
	 (r1 = 0)
	 (r2 = 0))))))

(define-ccl-program ccl-thai-xtis-ascii
  '(0
    (if (r1 == 0)
	(write r0)
      (if (r2 == 0)
	  ((r5 = r1) (r6 = r3) (call ccl-thai-xtis-write)
	   (write r0)
	   (r1 = 0))
	((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write)
	 (write r0)
	 (r1 = 0)
	 (r2 = 0))))))

(define-ccl-program ccl-thai-xtis-eof
  '(0
    (if (r1 != 0)
	(if (r2 == 0)
	    ((r5 = r1) (r6 = r3) (call ccl-thai-xtis-write))
	  ((r5 = r1) (r6 = r2) (call ccl-thai-xtis-write))))))

(define-ccl-program ccl-decode-thai-xtis
  `(4
    ((read r0)
     (r1 = 0)
     (r2 = 0)
     (r3 = #x30)
     (r4 = ,(charset-id 'thai-xtis))
     (loop
      (if (r0 < 161)
	  (call ccl-thai-xtis-ascii)
	(branch (r0 - 161)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-consonant)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-vowel-d1)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-vowel)
		(call ccl-thai-xtis-vowel)
		(call ccl-thai-xtis-vowel)
		(call ccl-thai-xtis-vowel)
		(call ccl-thai-xtis-vowel)
		(call ccl-thai-xtis-vowel)
		(call ccl-thai-xtis-vowel)
		nil
		nil
		nil
		nil
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-tone)
		(call ccl-thai-xtis-vowel-ee)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		(call ccl-thai-xtis-symbol)
		nil
		nil
		nil))
      (read r0)
      (repeat)))

    (call ccl-thai-xtis-eof)))

)

(defconst leading-code-private-21 #x9F)

(define-ccl-program ccl-encode-thai-xtis
  `(1
    ((read r0)
     (loop
      (if (r0 == ,leading-code-private-21)
	  ((read r1)
	   (if (r1 == ,(charset-id 'thai-xtis))
	       ((read r0)
		(write r0)
		(read r0)
		(r1 = (r0 & 7))
		(r0 = ((r0 - #xB0) >> 3))
		(if (r0 != 0)
		    (write r0 [0 209 212 213 214 215 216 217 218 238]))
		(if (r1 != 0)
		    (write r1 [0 231 232 233 234 235 236 237]))
		(read r0)
		(repeat))
	     ((write r0 r1)
	      (read r0)
	      (repeat))))
	(write-read-repeat r0))))))

(if (featurep 'xemacs)
    (progn
      (make-coding-system
       'tis-620 'ccl
       "TIS620 (Thai)"
       `(mnemonic "TIS620"
	 decode ccl-decode-thai-xtis
	 encode ccl-encode-thai-xtis
         safe-charsets (ascii thai-xtis)
	 documentation "external=tis620, internal=thai-xtis"))
      (coding-system-put 'tis-620 'category 'iso-8-1))
  (make-coding-system
   'tis-620 4 ?T "external=tis620, internal=thai-xtis"
   '(ccl-decode-thai-xtis . ccl-encode-thai-xtis)
   '((safe-charsets . t)))
  )


(set-language-info-alist
 "Thai-XTIS"
 '((charset thai-xtis)
   (coding-system tis-620 iso-2022-7bit)
   (tutorial . "TUTORIAL.th")
   (tutorial-coding-system . tis-620)
   (coding-priority tis-620 iso-2022-7bit)
   (sample-text . "$(?!:(B")
   (documentation . t)))

;; thai-xtis.el ends here.