HCoop / bpt / emacs.git / blame
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1 | ;;; hex-util.el --- Functions to encode/decode hexadecimal string. |
| 2 | ||
| 3 | ;; Copyright (C) 1999, 2001 Free Software Foundation, Inc. | |
| 4 | ||
| 5 | ;; Author: Shuhei KOBAYASHI <shuhei@aqua.ocn.ne.jp> | |
| 6 | ;; Keywords: data | |
| 7 | ||
| 8 | ;; This file is part of FLIM (Faithful Library about Internet Message). | |
| 9 | ||
| 10 | ;; This program is free software; you can redistribute it and/or | |
| 11 | ;; modify it under the terms of the GNU General Public License as | |
| 12 | ;; published by the Free Software Foundation; either version 2, or | |
| 13 | ;; (at your option) any later version. | |
| 14 | ||
| 15 | ;; This program is distributed in the hope that it will be useful, | |
| 16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 18 | ;; GNU General Public License for more details. | |
| 19 | ||
| 20 | ;; You should have received a copy of the GNU General Public License | |
| 21 | ;; along with this program; see the file COPYING. If not, write to | |
| 22 | ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 23 | ;; Boston, MA 02111-1307, USA. | |
| 24 | ||
| 25 | ;;; Commentary: | |
| 26 | ||
| 27 | ;;; Code: | |
| 28 | ||
| 29 | (eval-when-compile | |
| 30 | (defmacro hex-char-to-num (chr) | |
| 31 | (` (let ((chr (, chr))) | |
| 32 | (cond | |
| 33 | ((and (<= ?a chr)(<= chr ?f)) (+ (- chr ?a) 10)) | |
| 34 | ((and (<= ?A chr)(<= chr ?F)) (+ (- chr ?A) 10)) | |
| 35 | ((and (<= ?0 chr)(<= chr ?9)) (- chr ?0)) | |
| 36 | (t (error "Invalid hexadecimal digit `%c'" chr)))))) | |
| 37 | (defmacro num-to-hex-char (num) | |
| 38 | (` (aref "0123456789abcdef" (, num))))) | |
| 39 | ||
| 40 | (defun decode-hex-string (string) | |
| 41 | "Decode hexadecimal STRING to octet string." | |
| 42 | (let* ((len (length string)) | |
| 43 | (dst (make-string (/ len 2) 0)) | |
| 44 | (idx 0)(pos 0)) | |
| 45 | (while (< pos len) | |
| 46 | ;;; logior and lsh are not byte-coded. | |
| 47 | ;;; (aset dst idx (logior (lsh (hex-char-to-num (aref string pos)) 4) | |
| 48 | ;;; (hex-char-to-num (aref string (1+ pos))))) | |
| 49 | (aset dst idx (+ (* (hex-char-to-num (aref string pos)) 16) | |
| 50 | (hex-char-to-num (aref string (1+ pos))))) | |
| 51 | (setq idx (1+ idx) | |
| 52 | pos (+ 2 pos))) | |
| 53 | dst)) | |
| 54 | ||
| 55 | (defun encode-hex-string (string) | |
| 56 | "Encode octet STRING to hexadecimal string." | |
| 57 | (let* ((len (length string)) | |
| 58 | (dst (make-string (* len 2) 0)) | |
| 59 | (idx 0)(pos 0)) | |
| 60 | (while (< pos len) | |
| 61 | ;;; logand and lsh are not byte-coded. | |
| 62 | ;;; (aset dst idx (num-to-hex-char (logand (lsh (aref string pos) -4) 15))) | |
| 63 | (aset dst idx (num-to-hex-char (/ (aref string pos) 16))) | |
| 64 | (setq idx (1+ idx)) | |
| 65 | ;;; (aset dst idx (num-to-hex-char (logand (aref string pos) 15))) | |
| 66 | (aset dst idx (num-to-hex-char (% (aref string pos) 16))) | |
| 67 | (setq idx (1+ idx) | |
| 68 | pos (1+ pos))) | |
| 69 | dst)) | |
| 70 | ||
| 71 | (provide 'hex-util) | |
| 72 | ||
| 73 | ;;; arch-tag: fe8aaa79-6c86-400e-813f-5a8cc4cb3859 | |
| 74 | ;;; hex-util.el ends here |