lisp/gnus/binhex.el

   1 ;;; binhex.el --- elisp native binhex decode
   2
   3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007 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, or (at your option)
  14 ;; 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; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;;; Code:
  29
  30 (eval-when-compile (require 'cl))
  31
  32 (eval-and-compile
  33   (defalias 'binhex-char-int
  34     (if (fboundp 'char-int)
  35         'char-int
  36       'identity)))
  37
  38 (defcustom binhex-decoder-program "hexbin"
  39   "*Non-nil value should be a string that names a binhex decoder.
  40 The program should expect to read binhex data on its standard
  41 input and write the converted data to its standard output."
  42   :type 'string
  43   :group 'gnus-extract)
  44
  45 (defcustom binhex-decoder-switches '("-d")
  46   "*List of command line flags passed to the command `binhex-decoder-program'."
  47   :group 'gnus-extract
  48   :type '(repeat string))
  49
  50 (defcustom binhex-use-external
  51   (executable-find binhex-decoder-program)
  52   "*Use external binhex program."
  53   :version "22.1"
  54   :group 'gnus-extract
  55   :type 'boolean)
  56
  57 (defconst binhex-alphabet-decoding-alist
  58   '(( ?\! . 0) ( ?\" . 1) ( ?\# . 2) ( ?\$ . 3) ( ?\% . 4) ( ?\& . 5)
  59     ( ?\' . 6) ( ?\( . 7) ( ?\) . 8) ( ?\* . 9) ( ?\+ . 10) ( ?\, . 11)
  60     ( ?\- . 12) ( ?0 . 13) ( ?1 . 14) ( ?2 . 15) ( ?3 . 16) ( ?4 . 17)
  61     ( ?5 . 18) ( ?6 . 19) ( ?8 . 20) ( ?9 . 21) ( ?@ . 22) ( ?A . 23)
  62     ( ?B . 24) ( ?C . 25) ( ?D . 26) ( ?E . 27) ( ?F . 28) ( ?G . 29)
  63     ( ?H . 30) ( ?I . 31) ( ?J . 32) ( ?K . 33) ( ?L . 34) ( ?M . 35)
  64     ( ?N . 36) ( ?P . 37) ( ?Q . 38) ( ?R . 39) ( ?S . 40) ( ?T . 41)
  65     ( ?U . 42) ( ?V . 43) ( ?X . 44) ( ?Y . 45) ( ?Z . 46) ( ?\[ . 47)
  66     ( ?\` . 48) ( ?a . 49) ( ?b . 50) ( ?c . 51) ( ?d . 52) ( ?e . 53)
  67     ( ?f . 54) ( ?h . 55) ( ?i . 56) ( ?j . 57) ( ?k . 58) ( ?l . 59)
  68     ( ?m . 60) ( ?p . 61) ( ?q . 62) ( ?r . 63)))
  69
  70 (defun binhex-char-map (char)
  71   (cdr (assq char binhex-alphabet-decoding-alist)))
  72
  73 ;;;###autoload
  74 (defconst binhex-begin-line
  75   "^:...............................................................$")
  76 (defconst binhex-body-line
  77   "^[^:]...............................................................$")
  78 (defconst binhex-end-line ":$")
  79
  80 (defvar binhex-temporary-file-directory
  81   (cond ((fboundp 'temp-directory) (temp-directory))
  82         ((boundp 'temporary-file-directory) temporary-file-directory)
  83         ("/tmp/")))
  84
  85 (eval-and-compile
  86   (defalias 'binhex-insert-char
  87     (if (featurep 'xemacs)
  88         'insert-char
  89       (lambda (char &optional count ignored buffer)
  90         "Insert COUNT copies of CHARACTER into BUFFER."
  91         (if (or (null buffer) (eq buffer (current-buffer)))
  92             (insert-char char count)
  93           (with-current-buffer buffer
  94             (insert-char char count)))))))
  95
  96 (defvar binhex-crc-table
  97   [0  4129  8258  12387  16516  20645  24774  28903
  98       33032  37161  41290  45419  49548  53677  57806  61935
  99       4657  528  12915  8786  21173  17044  29431  25302
 100       37689  33560  45947  41818  54205  50076  62463  58334
 101       9314  13379  1056  5121  25830  29895  17572  21637
 102       42346  46411  34088  38153  58862  62927  50604  54669
 103       13907  9842  5649  1584  30423  26358  22165  18100
 104       46939  42874  38681  34616  63455  59390  55197  51132
 105       18628  22757  26758  30887  2112  6241  10242  14371
 106       51660  55789  59790  63919  35144  39273  43274  47403
 107       23285  19156  31415  27286  6769  2640  14899  10770
 108       56317  52188  64447  60318  39801  35672  47931  43802
 109       27814  31879  19684  23749  11298  15363  3168  7233
 110       60846  64911  52716  56781  44330  48395  36200  40265
 111       32407  28342  24277  20212  15891  11826  7761  3696
 112       65439  61374  57309  53244  48923  44858  40793  36728
 113       37256  33193  45514  41451  53516  49453  61774  57711
 114       4224  161  12482  8419  20484  16421  28742  24679
 115       33721  37784  41979  46042  49981  54044  58239  62302
 116       689  4752  8947  13010  16949  21012  25207  29270
 117       46570  42443  38312  34185  62830  58703  54572  50445
 118       13538  9411  5280  1153  29798  25671  21540  17413
 119       42971  47098  34713  38840  59231  63358  50973  55100
 120       9939  14066  1681  5808  26199  30326  17941  22068
 121       55628  51565  63758  59695  39368  35305  47498  43435
 122       22596  18533  30726  26663  6336  2273  14466  10403
 123       52093  56156  60223  64286  35833  39896  43963  48026
 124       19061  23124  27191  31254  2801  6864  10931  14994
 125       64814  60687  56684  52557  48554  44427  40424  36297
 126       31782  27655  23652  19525  15522  11395  7392  3265
 127       61215  65342  53085  57212  44955  49082  36825  40952
 128       28183  32310  20053  24180  11923  16050  3793  7920])
 129
 130 (defun binhex-update-crc (crc char &optional count)
 131   (if (null count) (setq count 1))
 132   (while (> count 0)
 133     (setq crc (logxor (logand (lsh crc 8) 65280)
 134                       (aref binhex-crc-table
 135                             (logxor (logand (lsh crc -8) 255)
 136                                     char)))
 137           count (1- count)))
 138   crc)
 139
 140 (defun binhex-verify-crc (buffer start end)
 141   (with-current-buffer buffer
 142     (let ((pos start) (crc 0) (last (- end 2)))
 143       (while (< pos last)
 144         (setq crc (binhex-update-crc crc (char-after pos))
 145               pos (1+ pos)))
 146       (if (= crc (binhex-string-big-endian (buffer-substring last end)))
 147           nil
 148         (error "CRC error")))))
 149
 150 (defun binhex-string-big-endian (string)
 151   (let ((ret 0) (i 0) (len (length string)))
 152     (while (< i len)
 153       (setq ret (+ (lsh ret 8) (binhex-char-int (aref string i)))
 154             i (1+ i)))
 155     ret))
 156
 157 (defun binhex-string-little-endian (string)
 158   (let ((ret 0) (i 0) (shift 0) (len (length string)))
 159     (while (< i len)
 160       (setq ret (+ ret (lsh (binhex-char-int (aref string i)) shift))
 161             i (1+ i)
 162             shift (+ shift 8)))
 163     ret))
 164
 165 (defun binhex-header (buffer)
 166   (with-current-buffer buffer
 167     (let ((pos (point-min)) len)
 168       (vector
 169        (prog1
 170            (setq len (binhex-char-int (char-after pos)))
 171          (setq pos (1+ pos)))
 172        (buffer-substring pos (setq pos (+ pos len)))
 173        (prog1
 174            (setq len (binhex-char-int (char-after pos)))
 175          (setq pos (1+ pos)))
 176        (buffer-substring pos (setq pos (+ pos 4)))
 177        (buffer-substring pos (setq pos (+ pos 4)))
 178        (binhex-string-big-endian
 179         (buffer-substring pos (setq pos (+ pos 2))))
 180        (binhex-string-big-endian
 181         (buffer-substring pos (setq pos (+ pos 4))))
 182        (binhex-string-big-endian
 183         (buffer-substring pos (setq pos (+ pos 4))))))))
 184
 185 (defvar binhex-last-char)
 186 (defvar binhex-repeat)
 187
 188 (defun binhex-push-char (char &optional count ignored buffer)
 189   (cond
 190    (binhex-repeat
 191     (if (eq char 0)
 192         (binhex-insert-char (setq binhex-last-char 144) 1
 193                             ignored buffer)
 194       (binhex-insert-char binhex-last-char (- char 1)
 195                           ignored buffer)
 196       (setq binhex-last-char nil))
 197     (setq binhex-repeat nil))
 198    ((= char 144)
 199     (setq binhex-repeat t))
 200    (t
 201     (binhex-insert-char (setq binhex-last-char char) 1 ignored buffer))))
 202
 203 ;;;###autoload
 204 (defun binhex-decode-region-internal (start end &optional header-only)
 205   "Binhex decode region between START and END without using an external program.
 206 If HEADER-ONLY is non-nil only decode header and return filename."
 207   (interactive "r")
 208   (let ((work-buffer nil)
 209         (counter 0)
 210         (bits 0) (tmp t)
 211         (lim 0) inputpos
 212         (non-data-chars " \t\n\r:")
 213         file-name-length data-fork-start
 214         header
 215         binhex-last-char binhex-repeat)
 216     (unwind-protect
 217         (save-excursion
 218           (goto-char start)
 219           (when (re-search-forward binhex-begin-line end t)
 220             (let (default-enable-multibyte-characters)
 221               (setq work-buffer (generate-new-buffer " *binhex-work*")))
 222             (beginning-of-line)
 223             (setq bits 0 counter 0)
 224             (while tmp
 225               (skip-chars-forward non-data-chars end)
 226               (setq inputpos (point))
 227               (end-of-line)
 228               (setq lim (point))
 229               (while (and (< inputpos lim)
 230                           (setq tmp (binhex-char-map (char-after inputpos))))
 231                 (setq bits (+ bits tmp)
 232                       counter (1+ counter)
 233                       inputpos (1+ inputpos))
 234                 (cond ((= counter 4)
 235                        (binhex-push-char (lsh bits -16) 1 nil work-buffer)
 236                        (binhex-push-char (logand (lsh bits -8) 255) 1 nil
 237                                          work-buffer)
 238                        (binhex-push-char (logand bits 255) 1 nil
 239                                          work-buffer)
 240                        (setq bits 0 counter 0))
 241                       (t (setq bits (lsh bits 6)))))
 242               (if (null file-name-length)
 243                   (with-current-buffer work-buffer
 244                     (setq file-name-length (char-after (point-min))
 245                           data-fork-start (+ (point-min)
 246                                              file-name-length 22))))
 247               (when (and (null header)
 248                          (with-current-buffer work-buffer
 249                            (>= (buffer-size) data-fork-start)))
 250                 (binhex-verify-crc work-buffer
 251                                    (point-min) data-fork-start)
 252                 (setq header (binhex-header work-buffer))
 253                 (when header-only (setq tmp nil counter 0)))
 254               (setq tmp (and tmp (not (eq inputpos end)))))
 255             (cond
 256              ((= counter 3)
 257               (binhex-push-char (logand (lsh bits -16) 255) 1 nil
 258                                 work-buffer)
 259               (binhex-push-char (logand (lsh bits -8) 255) 1 nil
 260                                 work-buffer))
 261              ((= counter 2)
 262               (binhex-push-char (logand (lsh bits -10) 255) 1 nil
 263                                 work-buffer))))
 264           (if header-only nil
 265             (binhex-verify-crc work-buffer
 266                                data-fork-start
 267                                (+ data-fork-start (aref header 6) 2))
 268             (or (markerp end) (setq end (set-marker (make-marker) end)))
 269             (goto-char start)
 270             (insert-buffer-substring work-buffer
 271                                      data-fork-start (+ data-fork-start
 272                                                         (aref header 6)))
 273             (delete-region (point) end)))
 274       (and work-buffer (kill-buffer work-buffer)))
 275     (if header (aref header 1))))
 276
 277 ;;;###autoload
 278 (defun binhex-decode-region-external (start end)
 279   "Binhex decode region between START and END using external decoder."
 280   (interactive "r")
 281   (let ((cbuf (current-buffer)) firstline work-buffer status
 282         (file-name (expand-file-name
 283                     (concat (binhex-decode-region-internal start end t)
 284                             ".data")
 285                     binhex-temporary-file-directory)))
 286     (save-excursion
 287       (goto-char start)
 288       (when (re-search-forward binhex-begin-line nil t)
 289         (let ((cdir default-directory) default-process-coding-system)
 290           (unwind-protect
 291               (progn
 292                 (set-buffer (setq work-buffer
 293                                   (generate-new-buffer " *binhex-work*")))
 294                 (buffer-disable-undo work-buffer)
 295                 (insert-buffer-substring cbuf firstline end)
 296                 (cd binhex-temporary-file-directory)
 297                 (apply 'call-process-region
 298                        (point-min)
 299                        (point-max)
 300                        binhex-decoder-program
 301                        nil
 302                        nil
 303                        nil
 304                        binhex-decoder-switches))
 305             (cd cdir) (set-buffer cbuf)))
 306         (if (and file-name (file-exists-p file-name))
 307             (progn
 308               (goto-char start)
 309               (delete-region start end)
 310               (let (format-alist)
 311                 (insert-file-contents-literally file-name)))
 312           (error "Can not binhex")))
 313       (and work-buffer (kill-buffer work-buffer))
 314       (ignore-errors
 315         (if file-name (delete-file file-name))))))
 316
 317 ;;;###autoload
 318 (defun binhex-decode-region (start end)
 319   "Binhex decode region between START and END."
 320   (interactive "r")
 321   (if binhex-use-external
 322       (binhex-decode-region-external start end)
 323     (binhex-decode-region-internal start end)))
 324
 325 (provide 'binhex)
 326
 327 ;;; arch-tag: 8476badd-1e76-4f1d-a640-f9a38c72eed8
 328 ;;; binhex.el ends here