lisp/mail/binhex.el

   1 ;;; binhex.el --- elisp native binhex decode
   2
   3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   5
   6 ;; Author: Shenghuo Zhu <zsh@cs.rochester.edu>
   7 ;; Keywords: binhex news
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28 (eval-when-compile (require 'cl))
  29
  30 (eval-and-compile
  31   (defalias 'binhex-char-int
  32     (if (fboundp 'char-int)
  33         'char-int
  34       'identity)))
  35
  36 (defgroup binhex nil
  37   "Decoding of BinHex (binary-to-hexadecimal) data."
  38   :group 'mail
  39   :group 'news)
  40
  41 (defcustom binhex-decoder-program "hexbin"
  42   "*Non-nil value should be a string that names a binhex decoder.
  43 The program should expect to read binhex data on its standard
  44 input and write the converted data to its standard output."
  45   :type 'string
  46   :group 'binhex)
  47
  48 (defcustom binhex-decoder-switches '("-d")
  49   "*List of command line flags passed to the command `binhex-decoder-program'."
  50   :group 'binhex
  51   :type '(repeat string))
  52
  53 (defcustom binhex-use-external
  54   (executable-find binhex-decoder-program)
  55   "*Use external binhex program."
  56   :version "22.1"
  57   :group 'binhex
  58   :type 'boolean)
  59
  60 (defconst binhex-alphabet-decoding-alist
  61   '(( ?\! . 0) ( ?\" . 1) ( ?\# . 2) ( ?\$ . 3) ( ?\% . 4) ( ?\& . 5)
  62     ( ?\' . 6) ( ?\( . 7) ( ?\) . 8) ( ?\* . 9) ( ?\+ . 10) ( ?\, . 11)
  63     ( ?\- . 12) ( ?0 . 13) ( ?1 . 14) ( ?2 . 15) ( ?3 . 16) ( ?4 . 17)
  64     ( ?5 . 18) ( ?6 . 19) ( ?8 . 20) ( ?9 . 21) ( ?@ . 22) ( ?A . 23)
  65     ( ?B . 24) ( ?C . 25) ( ?D . 26) ( ?E . 27) ( ?F . 28) ( ?G . 29)
  66     ( ?H . 30) ( ?I . 31) ( ?J . 32) ( ?K . 33) ( ?L . 34) ( ?M . 35)
  67     ( ?N . 36) ( ?P . 37) ( ?Q . 38) ( ?R . 39) ( ?S . 40) ( ?T . 41)
  68     ( ?U . 42) ( ?V . 43) ( ?X . 44) ( ?Y . 45) ( ?Z . 46) ( ?\[ . 47)
  69     ( ?\` . 48) ( ?a . 49) ( ?b . 50) ( ?c . 51) ( ?d . 52) ( ?e . 53)
  70     ( ?f . 54) ( ?h . 55) ( ?i . 56) ( ?j . 57) ( ?k . 58) ( ?l . 59)
  71     ( ?m . 60) ( ?p . 61) ( ?q . 62) ( ?r . 63)))
  72
  73 (defun binhex-char-map (char)
  74   (cdr (assq char binhex-alphabet-decoding-alist)))
  75
  76 ;;;###autoload
  77 (defconst binhex-begin-line
  78   "^:...............................................................$")
  79 (defconst binhex-body-line
  80   "^[^:]...............................................................$")
  81 (defconst binhex-end-line ":$")
  82
  83 (defvar binhex-temporary-file-directory
  84   (cond ((fboundp 'temp-directory) (temp-directory))
  85         ((boundp 'temporary-file-directory) temporary-file-directory)
  86         ("/tmp/")))
  87
  88 (eval-and-compile
  89   (defalias 'binhex-insert-char
  90     (if (featurep 'xemacs)
  91         'insert-char
  92       (lambda (char &optional count ignored buffer)
  93         "Insert COUNT copies of CHARACTER into BUFFER."
  94         (if (or (null buffer) (eq buffer (current-buffer)))
  95             (insert-char char count)
  96           (with-current-buffer buffer
  97             (insert-char char count)))))))
  98
  99 (defvar binhex-crc-table
 100   [0  4129  8258  12387  16516  20645  24774  28903
 101       33032  37161  41290  45419  49548  53677  57806  61935
 102       4657  528  12915  8786  21173  17044  29431  25302
 103       37689  33560  45947  41818  54205  50076  62463  58334
 104       9314  13379  1056  5121  25830  29895  17572  21637
 105       42346  46411  34088  38153  58862  62927  50604  54669
 106       13907  9842  5649  1584  30423  26358  22165  18100
 107       46939  42874  38681  34616  63455  59390  55197  51132
 108       18628  22757  26758  30887  2112  6241  10242  14371
 109       51660  55789  59790  63919  35144  39273  43274  47403
 110       23285  19156  31415  27286  6769  2640  14899  10770
 111       56317  52188  64447  60318  39801  35672  47931  43802
 112       27814  31879  19684  23749  11298  15363  3168  7233
 113       60846  64911  52716  56781  44330  48395  36200  40265
 114       32407  28342  24277  20212  15891  11826  7761  3696
 115       65439  61374  57309  53244  48923  44858  40793  36728
 116       37256  33193  45514  41451  53516  49453  61774  57711
 117       4224  161  12482  8419  20484  16421  28742  24679
 118       33721  37784  41979  46042  49981  54044  58239  62302
 119       689  4752  8947  13010  16949  21012  25207  29270
 120       46570  42443  38312  34185  62830  58703  54572  50445
 121       13538  9411  5280  1153  29798  25671  21540  17413
 122       42971  47098  34713  38840  59231  63358  50973  55100
 123       9939  14066  1681  5808  26199  30326  17941  22068
 124       55628  51565  63758  59695  39368  35305  47498  43435
 125       22596  18533  30726  26663  6336  2273  14466  10403
 126       52093  56156  60223  64286  35833  39896  43963  48026
 127       19061  23124  27191  31254  2801  6864  10931  14994
 128       64814  60687  56684  52557  48554  44427  40424  36297
 129       31782  27655  23652  19525  15522  11395  7392  3265
 130       61215  65342  53085  57212  44955  49082  36825  40952
 131       28183  32310  20053  24180  11923  16050  3793  7920])
 132
 133 (defun binhex-update-crc (crc char &optional count)
 134   (if (null count) (setq count 1))
 135   (while (> count 0)
 136     (setq crc (logxor (logand (lsh crc 8) 65280)
 137                       (aref binhex-crc-table
 138                             (logxor (logand (lsh crc -8) 255)
 139                                     char)))
 140           count (1- count)))
 141   crc)
 142
 143 (defun binhex-verify-crc (buffer start end)
 144   (with-current-buffer buffer
 145     (let ((pos start) (crc 0) (last (- end 2)))
 146       (while (< pos last)
 147         (setq crc (binhex-update-crc crc (char-after pos))
 148               pos (1+ pos)))
 149       (if (= crc (binhex-string-big-endian (buffer-substring last end)))
 150           nil
 151         (error "CRC error")))))
 152
 153 (defun binhex-string-big-endian (string)
 154   (let ((ret 0) (i 0) (len (length string)))
 155     (while (< i len)
 156       (setq ret (+ (lsh ret 8) (binhex-char-int (aref string i)))
 157             i (1+ i)))
 158     ret))
 159
 160 (defun binhex-string-little-endian (string)
 161   (let ((ret 0) (i 0) (shift 0) (len (length string)))
 162     (while (< i len)
 163       (setq ret (+ ret (lsh (binhex-char-int (aref string i)) shift))
 164             i (1+ i)
 165             shift (+ shift 8)))
 166     ret))
 167
 168 (defun binhex-header (buffer)
 169   (with-current-buffer buffer
 170     (let ((pos (point-min)) len)
 171       (vector
 172        (prog1
 173            (setq len (binhex-char-int (char-after pos)))
 174          (setq pos (1+ pos)))
 175        (buffer-substring pos (setq pos (+ pos len)))
 176        (prog1
 177            (setq len (binhex-char-int (char-after pos)))
 178          (setq pos (1+ pos)))
 179        (buffer-substring pos (setq pos (+ pos 4)))
 180        (buffer-substring pos (setq pos (+ pos 4)))
 181        (binhex-string-big-endian
 182         (buffer-substring pos (setq pos (+ pos 2))))
 183        (binhex-string-big-endian
 184         (buffer-substring pos (setq pos (+ pos 4))))
 185        (binhex-string-big-endian
 186         (buffer-substring pos (setq pos (+ pos 4))))))))
 187
 188 (defvar binhex-last-char)
 189 (defvar binhex-repeat)
 190
 191 (defun binhex-push-char (char &optional count ignored buffer)
 192   (cond
 193    (binhex-repeat
 194     (if (eq char 0)
 195         (binhex-insert-char (setq binhex-last-char 144) 1
 196                             ignored buffer)
 197       (binhex-insert-char binhex-last-char (- char 1)
 198                           ignored buffer)
 199       (setq binhex-last-char nil))
 200     (setq binhex-repeat nil))
 201    ((= char 144)
 202     (setq binhex-repeat t))
 203    (t
 204     (binhex-insert-char (setq binhex-last-char char) 1 ignored buffer))))
 205
 206 ;;;###autoload
 207 (defun binhex-decode-region-internal (start end &optional header-only)
 208   "Binhex decode region between START and END without using an external program.
 209 If HEADER-ONLY is non-nil only decode header and return filename."
 210   (interactive "r")
 211   (let ((work-buffer nil)
 212         (counter 0)
 213         (bits 0) (tmp t)
 214         (lim 0) inputpos
 215         (non-data-chars " \t\n\r:")
 216         file-name-length data-fork-start
 217         header
 218         binhex-last-char binhex-repeat)
 219     (unwind-protect
 220         (save-excursion
 221           (goto-char start)
 222           (when (re-search-forward binhex-begin-line end t)
 223             (setq work-buffer (generate-new-buffer " *binhex-work*"))
 224             (with-current-buffer work-buffer (set-buffer-multibyte nil))
 225             (beginning-of-line)
 226             (setq bits 0 counter 0)
 227             (while tmp
 228               (skip-chars-forward non-data-chars end)
 229               (setq inputpos (point))
 230               (end-of-line)
 231               (setq lim (point))
 232               (while (and (< inputpos lim)
 233                           (setq tmp (binhex-char-map (char-after inputpos))))
 234                 (setq bits (+ bits tmp)
 235                       counter (1+ counter)
 236                       inputpos (1+ inputpos))
 237                 (cond ((= counter 4)
 238                        (binhex-push-char (lsh bits -16) 1 nil work-buffer)
 239                        (binhex-push-char (logand (lsh bits -8) 255) 1 nil
 240                                          work-buffer)
 241                        (binhex-push-char (logand bits 255) 1 nil
 242                                          work-buffer)
 243                        (setq bits 0 counter 0))
 244                       (t (setq bits (lsh bits 6)))))
 245               (if (null file-name-length)
 246                   (with-current-buffer work-buffer
 247                     (setq file-name-length (char-after (point-min))
 248                           data-fork-start (+ (point-min)
 249                                              file-name-length 22))))
 250               (when (and (null header)
 251                          (with-current-buffer work-buffer
 252                            (>= (buffer-size) data-fork-start)))
 253                 (binhex-verify-crc work-buffer
 254                                    (point-min) data-fork-start)
 255                 (setq header (binhex-header work-buffer))
 256                 (when header-only (setq tmp nil counter 0)))
 257               (setq tmp (and tmp (not (eq inputpos end)))))
 258             (cond
 259              ((= counter 3)
 260               (binhex-push-char (logand (lsh bits -16) 255) 1 nil
 261                                 work-buffer)
 262               (binhex-push-char (logand (lsh bits -8) 255) 1 nil
 263                                 work-buffer))
 264              ((= counter 2)
 265               (binhex-push-char (logand (lsh bits -10) 255) 1 nil
 266                                 work-buffer))))
 267           (if header-only nil
 268             (binhex-verify-crc work-buffer
 269                                data-fork-start
 270                                (+ data-fork-start (aref header 6) 2))
 271             (or (markerp end) (setq end (set-marker (make-marker) end)))
 272             (goto-char start)
 273             (insert-buffer-substring work-buffer
 274                                      data-fork-start (+ data-fork-start
 275                                                         (aref header 6)))
 276             (delete-region (point) end)))
 277       (and work-buffer (kill-buffer work-buffer)))
 278     (if header (aref header 1))))
 279
 280 ;;;###autoload
 281 (defun binhex-decode-region-external (start end)
 282   "Binhex decode region between START and END using external decoder."
 283   (interactive "r")
 284   (let ((cbuf (current-buffer)) firstline work-buffer status
 285         (file-name (expand-file-name
 286                     (concat (binhex-decode-region-internal start end t)
 287                             ".data")
 288                     binhex-temporary-file-directory)))
 289     (save-excursion
 290       (goto-char start)
 291       (when (re-search-forward binhex-begin-line nil t)
 292         (let ((cdir default-directory) default-process-coding-system)
 293           (unwind-protect
 294               (progn
 295                 (set-buffer (setq work-buffer
 296                                   (generate-new-buffer " *binhex-work*")))
 297                 (buffer-disable-undo work-buffer)
 298                 (insert-buffer-substring cbuf firstline end)
 299                 (cd binhex-temporary-file-directory)
 300                 (apply 'call-process-region
 301                        (point-min)
 302                        (point-max)
 303                        binhex-decoder-program
 304                        nil
 305                        nil
 306                        nil
 307                        binhex-decoder-switches))
 308             (cd cdir) (set-buffer cbuf)))
 309         (if (and file-name (file-exists-p file-name))
 310             (progn
 311               (goto-char start)
 312               (delete-region start end)
 313               (let (format-alist)
 314                 (insert-file-contents-literally file-name)))
 315           (error "Can not binhex")))
 316       (and work-buffer (kill-buffer work-buffer))
 317       (ignore-errors
 318         (if file-name (delete-file file-name))))))
 319
 320 ;;;###autoload
 321 (defun binhex-decode-region (start end)
 322   "Binhex decode region between START and END."
 323   (interactive "r")
 324   (if binhex-use-external
 325       (binhex-decode-region-external start end)
 326     (binhex-decode-region-internal start end)))
 327
 328 (provide 'binhex)
 329
 330 ;; arch-tag: 8476badd-1e76-4f1d-a640-f9a38c72eed8
 331 ;;; binhex.el ends here