;;; po-compat.el --- basic support of PO translation files -*- coding: latin-1; -*-
;; Copyright (C) 1995-2002, 2010, 2016, 2019 Free Software Foundation, Inc.
;; Authors: François Pinard <pinard@iro.umontreal.ca>,
;; Greg McGary <gkm@magilla.cichlid.com>,
;; Bruno Haible <bruno@clisp.org>.
;; Keywords: i18n, files
;; This file is part of GNU gettext.
;; GNU gettext 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.
;; GNU gettext 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, see
;; <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Emacs 21.2 and newer already contain this file, under the name po.el,
;; and without portability hassles.
;; This package makes sure visiting PO files decodes them correctly,
;; according to the Charset= header in the PO file. For more support
;; for editing PO files, see po-mode.el.
;;; Code:
;;; Emacs portability matters.
(defconst po-content-type-charset-alist
'(; Note: Emacs 21 doesn't support all encodings, thus the missing entries.
("ASCII" . undecided)
("ANSI_X3.4-1968" . undecided)
("US-ASCII" . undecided)
("ISO-8859-1" . iso-8859-1)
("ISO_8859-1" . iso-8859-1)
("ISO-8859-2" . iso-8859-2)
("ISO_8859-2" . iso-8859-2)
("ISO-8859-3" . iso-8859-3)
("ISO_8859-3" . iso-8859-3)
("ISO-8859-4" . iso-8859-4)
("ISO_8859-4" . iso-8859-4)
("ISO-8859-5" . iso-8859-5)
("ISO_8859-5" . iso-8859-5)
;("ISO-8859-6" . ??)
;("ISO_8859-6" . ??)
("ISO-8859-7" . iso-8859-7)
("ISO_8859-7" . iso-8859-7)
("ISO-8859-8" . iso-8859-8)
("ISO_8859-8" . iso-8859-8)
("ISO-8859-9" . iso-8859-9)
("ISO_8859-9" . iso-8859-9)
;("ISO-8859-13" . ??)
;("ISO_8859-13" . ??)
;("ISO-8859-14" . ??)
;("ISO_8859-14" . ??)
("ISO-8859-15" . iso-8859-15)
("ISO_8859-15" . iso-8859-15)
("KOI8-R" . koi8-r)
;("KOI8-U" . ??)
;("KOI8-T" . ??)
("CP437" . cp437)
("CP775" . cp775)
("CP850" . cp850)
("CP852" . cp852)
("CP855" . cp855)
;("CP856" . ??)
("CP857" . cp857)
("CP861" . cp861)
("CP862" . cp862)
("CP864" . cp864)
("CP865" . cp865)
("CP866" . cp866)
("CP869" . cp869)
;("CP874" . ??)
;("CP922" . ??)
;("CP932" . ??)
;("CP943" . ??)
;("CP949" . ??)
;("CP950" . ??)
;("CP1046" . ??)
;("CP1124" . ??)
;("CP1129" . ??)
("CP1250" . cp1250)
("CP1251" . cp1251)
("CP1252" . iso-8859-1) ; approximation
("CP1253" . cp1253)
("CP1254" . iso-8859-9) ; approximation
("CP1255" . iso-8859-8) ; approximation
;("CP1256" . ??)
("CP1257" . cp1257)
("GB2312" . cn-gb-2312) ; also named 'gb2312' and 'euc-cn'
("EUC-JP" . euc-jp)
("EUC-KR" . euc-kr)
;("EUC-TW" . ??)
("BIG5" . big5)
;("BIG5-HKSCS" . ??)
;("GBK" . ??)
;("GB18030" . ??)
("SHIFT_JIS" . shift_jis)
;("JOHAB" . ??)
("TIS-620" . tis-620)
("VISCII" . viscii)
;("GEORGIAN-PS" . ??)
("UTF-8" . utf-8)
)
"How to convert a GNU libc/libiconv canonical charset name as seen in
Content-Type into a Mule coding system.")
(defun po-find-charset (filename)
"Return PO file charset value."
(interactive)
(let ((charset-regexp
"^\"Content-Type: text/plain;[ \t]*charset=\\(.*\\)\\\\n\"")
(short-read nil))
;; Try the first 4096 bytes. In case we cannot find the charset value
;; within the first 4096 bytes (the PO file might start with a long
;; comment) try the next 4096 bytes repeatedly until we'll know for sure
;; we've checked the empty header entry entirely.
(while (not (or short-read (re-search-forward "^msgid" nil t)))
(save-excursion
(goto-char (point-max))
(let ((pair (insert-file-contents-literally filename nil
(1- (point))
(1- (+ (point) 4096)))))
(setq short-read (< (nth 1 pair) 4096)))))
(cond ((re-search-forward charset-regexp nil t) (match-string 1))
(short-read nil)
;; We've found the first msgid; maybe, only a part of the msgstr
;; value was loaded. Load the next 1024 bytes; if charset still
;; isn't available, give up.
(t (save-excursion
(goto-char (point-max))
(insert-file-contents-literally filename nil
(1- (point))
(1- (+ (point) 1024))))
(if (re-search-forward charset-regexp nil t)
(match-string 1))))))
;;;###autoload (autoload 'po-find-file-coding-system "po-compat")
(defun po-find-file-coding-system-guts (operation filename)
"\
Return a Mule (DECODING . ENCODING) pair, according to PO file charset.
Called through file-coding-system-alist, before the file is visited for real."
(and (eq operation 'insert-file-contents)
(file-exists-p filename)
(po-with-temp-buffer
(let* ((coding-system-for-read 'no-conversion)
(charset (or (po-find-charset filename) "ascii"))
(charset-upper (upcase charset))
(charset-lower (downcase charset))
(candidate
(cdr (assoc charset-upper po-content-type-charset-alist)))
(try-symbol (or candidate (intern-soft charset-lower)))
(try-string
(if try-symbol (symbol-name try-symbol) charset-lower)))
(list (cond ((and try-symbol (coding-system-p try-symbol))
try-symbol)
((and (not (string-lessp "23" emacs-version))
(string-match "\\`cp[1-9][0-9][0-9]?\\'"
try-string)
(assoc (substring try-string 2)
(cp-supported-codepages)))
(codepage-setup (substring try-string 2))
(intern try-string))
(t
'no-conversion)))))))
(defun po-find-file-coding-system (arg-list)
"\
Return a Mule (DECODING . ENCODING) pair, according to PO file charset.
Called through file-coding-system-alist, before the file is visited for real."
(po-find-file-coding-system-guts (car arg-list) (car (cdr arg-list))))
(provide 'po-compat)
;;; Testing this file:
;; For each pofile in {
;; cs.po ; gettext/po/cs.el, charset=ISO-8859-2
;; cs-modified.po ; gettext/po/cs.el, charset=ISO_8859-2
;; de.po ; gettext/po/de.el, charset=UTF-8, if $emacsimpl = emacs
;; } do
;; Start $emacsimpl
;; M-x load-file po-compat.el RET
;; C-x C-f $pofile RET
;; Verify charset marker in status line ('2' = ISO-8859-2, 'u' = UTF-8).
;;; po-compat.el ends here