;;; idn.el --- Recommended Identifier Profiles for IDN
;;
;; Author: Lennart Borgman (lennart O borgman A gmail O com)
;; Created: 2010-03-24 Wed
;; Version: 0.1
;; Last-Updated: 2010-03-24 Wed
;; URL:
;; Keywords:
;; Compatibility:
;;
;; Features that might be required by this library:
;;
;;   None
;;
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;;
;;; Commentary:
;;
;; Functions for handling IDN chars defined by
;; `http://www.unicode.org/reports/tr39/'.
;;
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;;
;;; Change log:
;;
;;
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;;
;; 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 3, 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 this program; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth
;; Floor, Boston, MA 02110-1301, USA.
;;
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;;
;;; Code:

(defvar uts39-datadir "c:/uts39/data/")

(defun idn-init (bv)
  (let* ((idnchars-file (expand-file-name "idnchars.txt" uts39-datadir))
         (idnchars-old (find-buffer-visiting idnchars-file))
         (idnchars-buf (or idnchars-old
                           (if (not (file-exists-p idnchars-file))
                               (message "Can't find file %S" idnchars-file)
                             (find-file-noselect idnchars-file))))
         here
         (range-patt (rx bol
                         (group (repeat 4 (any xdigit)))
                         (optional ".."
                                   (group (repeat 4 (any xdigit)))))))
    (when idnchars-buf
      (with-current-buffer idnchars-buf
        (setq here (point))
        (save-restriction
          (widen)
          (goto-char (point-min))
          (while (re-search-forward range-patt nil t)
            (let* ((str-beg (match-string 0))
                   (str-end (match-string 1))
                   (beg (string-to-number str-beg 16))
                   (end (or (when str-end (string-to-number str-end 16))
                            beg)))
              (dotimes (ii (1+ (- end beg)))
                (aset bv (+ ii beg) t)))))
        (goto-char here))
      (unless idnchars-old (kill-buffer idnchars-buf))
      t)))

(defconst idn-chars
  "Boolean vector with recommended IDN chars.
See URL `http://www.unicode.org/reports/tr39/'.

Data is initialized from the file idnchars.txt in the directory
`uts39-datadir'.  This file is fetched from the above location."
  (let ((bv (make-bool-vector (1- (* 256 256)) nil)))
    (when (idn-init bv)
      ;; (string-to-number "002D" 16)
      ;; Make a quick sanity check:
      (unless (and (not (aref idn-chars 44))
                   (aref idn-chars 45))
        (message "idn-chars: Bad idn data in file idnchars.txt"))
      bv)))

(provide 'idn)
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;;; idn.el ends here