lisp/hexl.el

   1 ;;; hexl.el --- edit a file in a hex dump format using the hexl filter
   2
   3 ;; Copyright (C) 1989, 1994, 1998, 2001, 2002, 2003 Free Software Foundation, Inc.
   4
   5 ;; Author: Keith Gabryelski <ag@wheaties.ai.mit.edu>
   6 ;; Maintainer: FSF
   7 ;; Keywords: data
   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 2, 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., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This package implements a major mode for editing binary files.  It uses
  29 ;; a program called hexl, supplied with the GNU Emacs distribution, that
  30 ;; can filter a binary into an editable format or from the format back into
  31 ;; binary.  For full instructions, invoke `hexl-mode' on an empty buffer and
  32 ;; do M-x `describe-mode'.
  33 ;;
  34 ;; NOTE: Remember to change `hexl-program' or `hexl-options' if needed.
  35 ;;
  36 ;; Currently hexl only supports big endian hex output with 16 bit
  37 ;; grouping.
  38 ;;
  39 ;; -iso in `hexl-options' will allow iso characters to display in the
  40 ;; ASCII region of the screen (if your emacs supports this) instead of
  41 ;; changing them to dots.
  42
  43 ;;; Code:
  44
  45 ;;
  46 ;; vars here
  47 ;;
  48
  49 (defgroup hexl nil
  50   "Edit a file in a hex dump format using the hexl filter."
  51   :group 'data)
  52
  53
  54 (defcustom hexl-program "hexl"
  55   "The program that will hexlify and dehexlify its stdin.
  56 `hexl-program' will always be concatenated with `hexl-options'
  57 and \"-de\" when dehexlifying a buffer."
  58   :type 'string
  59   :group 'hexl)
  60
  61 (defcustom hexl-iso ""
  62   "If your emacs can handle ISO characters, this should be set to
  63 \"-iso\" otherwise it should be \"\"."
  64   :type 'string
  65   :group 'hexl)
  66
  67 (defcustom hexl-options (format "-hex %s" hexl-iso)
  68   "Space separated options to `hexl-program' that suit your needs.
  69 Quoting cannot be used, so the arguments cannot themselves contain spaces."
  70   :type 'string
  71   :group 'hexl)
  72
  73 (defcustom hexl-follow-ascii t
  74   "If non-nil then highlight the ASCII character corresponding to point."
  75   :type 'boolean
  76   :group 'hexl
  77   :version "20.3")
  78
  79 (defvar hexl-max-address 0
  80   "Maximum offset into hexl buffer.")
  81
  82 (defvar hexl-mode-map nil)
  83
  84 (defvar hexl-mode-old-local-map)
  85 (defvar hexl-mode-old-mode-name)
  86 (defvar hexl-mode-old-major-mode)
  87 (defvar hexl-mode-old-isearch-search-fun-function)
  88 (defvar hexl-mode-old-require-final-newline)
  89 (defvar hexl-mode-old-syntax-table)
  90
  91 (defvar hexl-ascii-overlay nil
  92   "Overlay used to highlight ASCII element corresponding to current point.")
  93 (make-variable-buffer-local 'hexl-ascii-overlay)
  94
  95 ;; routines
  96
  97 (put 'hexl-mode 'mode-class 'special)
  98
  99 ;;;###autoload
 100 (defun hexl-mode (&optional arg)
 101   "\\<hexl-mode-map>A mode for editing binary files in hex dump format.
 102 This is not an ordinary major mode; it alters some aspects
 103 of the current mode's behavior, but not all; also, you can exit
 104 Hexl mode and return to the previous mode using `hexl-mode-exit'.
 105
 106 This function automatically converts a buffer into the hexl format
 107 using the function `hexlify-buffer'.
 108
 109 Each line in the buffer has an \"address\" (displayed in hexadecimal)
 110 representing the offset into the file that the characters on this line
 111 are at and 16 characters from the file (displayed as hexadecimal
 112 values grouped every 16 bits) and as their ASCII values.
 113
 114 If any of the characters (displayed as ASCII characters) are
 115 unprintable (control or meta characters) they will be replaced as
 116 periods.
 117
 118 If `hexl-mode' is invoked with an argument the buffer is assumed to be
 119 in hexl format.
 120
 121 A sample format:
 122
 123   HEX ADDR: 0001 0203 0405 0607 0809 0a0b 0c0d 0e0f     ASCII-TEXT
 124   --------  ---- ---- ---- ---- ---- ---- ---- ----  ----------------
 125   00000000: 5468 6973 2069 7320 6865 786c 2d6d 6f64  This is hexl-mod
 126   00000010: 652e 2020 4561 6368 206c 696e 6520 7265  e.  Each line re
 127   00000020: 7072 6573 656e 7473 2031 3620 6279 7465  presents 16 byte
 128   00000030: 7320 6173 2068 6578 6164 6563 696d 616c  s as hexadecimal
 129   00000040: 2041 5343 4949 0a61 6e64 2070 7269 6e74   ASCII.and print
 130   00000050: 6162 6c65 2041 5343 4949 2063 6861 7261  able ASCII chara
 131   00000060: 6374 6572 732e 2020 416e 7920 636f 6e74  cters.  Any cont
 132   00000070: 726f 6c20 6f72 206e 6f6e 2d41 5343 4949  rol or non-ASCII
 133   00000080: 2063 6861 7261 6374 6572 730a 6172 6520   characters.are
 134   00000090: 6469 7370 6c61 7965 6420 6173 2070 6572  displayed as per
 135   000000a0: 696f 6473 2069 6e20 7468 6520 7072 696e  iods in the prin
 136   000000b0: 7461 626c 6520 6368 6172 6163 7465 7220  table character
 137   000000c0: 7265 6769 6f6e 2e0a                      region..
 138
 139 Movement is as simple as movement in a normal emacs text buffer.  Most
 140 cursor movement bindings are the same (ie. Use \\[hexl-backward-char], \\[hexl-forward-char], \\[hexl-next-line], and \\[hexl-previous-line]
 141 to move the cursor left, right, down, and up).
 142
 143 Advanced cursor movement commands (ala \\[hexl-beginning-of-line], \\[hexl-end-of-line], \\[hexl-beginning-of-buffer], and \\[hexl-end-of-buffer]) are
 144 also supported.
 145
 146 There are several ways to change text in hexl mode:
 147
 148 ASCII characters (character between space (0x20) and tilde (0x7E)) are
 149 bound to self-insert so you can simply type the character and it will
 150 insert itself (actually overstrike) into the buffer.
 151
 152 \\[hexl-quoted-insert] followed by another keystroke allows you to insert the key even if
 153 it isn't bound to self-insert.  An octal number can be supplied in place
 154 of another key to insert the octal number's ASCII representation.
 155
 156 \\[hexl-insert-hex-char] will insert a given hexadecimal value (if it is between 0 and 0xFF)
 157 into the buffer at the current point.
 158
 159 \\[hexl-insert-octal-char] will insert a given octal value (if it is between 0 and 0377)
 160 into the buffer at the current point.
 161
 162 \\[hexl-insert-decimal-char] will insert a given decimal value (if it is between 0 and 255)
 163 into the buffer at the current point.
 164
 165 \\[hexl-mode-exit] will exit hexl-mode.
 166
 167 Note: saving the file with any of the usual Emacs commands
 168 will actually convert it back to binary format while saving.
 169
 170 You can use \\[hexl-find-file] to visit a file in Hexl mode.
 171
 172 \\[describe-bindings] for advanced commands."
 173   (interactive "p")
 174   (unless (eq major-mode 'hexl-mode)
 175     (let ((modified (buffer-modified-p))
 176           (inhibit-read-only t)
 177           (original-point (- (point) (point-min)))
 178           max-address)
 179       (and (eobp) (not (bobp))
 180            (setq original-point (1- original-point)))
 181       (if (not (or (eq arg 1) (not arg)))
 182           ;; if no argument then we guess at hexl-max-address
 183           (setq max-address (+ (* (/ (1- (buffer-size)) 68) 16) 15))
 184         (setq max-address (1- (buffer-size)))
 185         ;; If the buffer's EOL type is -dos, we need to account for
 186         ;; extra CR characters added when hexlify-buffer writes the
 187         ;; buffer to a file.
 188         (when (eq (coding-system-eol-type buffer-file-coding-system) 1)
 189           (setq max-address (+ (count-lines (point-min) (point-max))
 190                                max-address))
 191           ;; But if there's no newline at the last line, we are off by
 192           ;; one; adjust.
 193           (or (eq (char-before (point-max)) ?\n)
 194               (setq max-address (1- max-address)))
 195           (setq original-point (+ (count-lines (point-min) (point))
 196                                   original-point))
 197           (or (bolp) (setq original-point (1- original-point))))
 198         (hexlify-buffer)
 199         (set-buffer-modified-p modified))
 200       (make-local-variable 'hexl-max-address)
 201       (setq hexl-max-address max-address)
 202       (hexl-goto-address original-point))
 203
 204     ;; We do not turn off the old major mode; instead we just
 205     ;; override most of it.  That way, we can restore it perfectly.
 206     (make-local-variable 'hexl-mode-old-local-map)
 207     (setq hexl-mode-old-local-map (current-local-map))
 208     (use-local-map hexl-mode-map)
 209
 210     (make-local-variable 'hexl-mode-old-mode-name)
 211     (setq hexl-mode-old-mode-name mode-name)
 212     (setq mode-name "Hexl")
 213
 214     (set (make-local-variable 'hexl-mode-old-isearch-search-fun-function)
 215          isearch-search-fun-function)
 216     (set (make-local-variable 'isearch-search-fun-function)
 217          'hexl-isearch-search-function)
 218
 219     (make-local-variable 'hexl-mode-old-major-mode)
 220     (setq hexl-mode-old-major-mode major-mode)
 221     (setq major-mode 'hexl-mode)
 222
 223     (make-local-variable 'hexl-mode-old-syntax-table)
 224     (setq hexl-mode-old-syntax-table (syntax-table))
 225     (set-syntax-table (standard-syntax-table))
 226
 227     (add-hook 'write-contents-functions 'hexl-save-buffer nil t)
 228
 229     (make-local-variable 'hexl-mode-old-require-final-newline)
 230     (setq hexl-mode-old-require-final-newline require-final-newline)
 231     (make-local-variable 'require-final-newline)
 232     (setq require-final-newline nil)
 233
 234     ;; Add hooks to rehexlify or dehexlify on various events.
 235     (add-hook 'after-revert-hook 'hexl-after-revert-hook nil t)
 236
 237     (add-hook 'change-major-mode-hook 'hexl-maybe-dehexlify-buffer nil t)
 238
 239     (if hexl-follow-ascii (hexl-follow-ascii 1)))
 240   (run-hooks 'hexl-mode-hook))
 241
 242
 243 (defun hexl-isearch-search-function ()
 244   (if (and (not isearch-regexp) (not isearch-word))
 245       (lambda (string &optional bound noerror count)
 246         (funcall
 247          (if isearch-forward 're-search-forward 're-search-backward)
 248          (if (> (length string) 80)
 249              (regexp-quote string)
 250            (mapconcat 'string string "\\(?:\n\\(?:[:a-f0-9]+ \\)+ \\)?"))
 251          bound noerror count))
 252     (let ((isearch-search-fun-function nil))
 253       (isearch-search-fun))))
 254
 255 (defun hexl-after-revert-hook ()
 256   (setq hexl-max-address (1- (buffer-size)))
 257   (hexlify-buffer)
 258   (set-buffer-modified-p nil))
 259
 260 (defvar hexl-in-save-buffer nil)
 261
 262 (defun hexl-save-buffer ()
 263   "Save a hexl format buffer as binary in visited file if modified."
 264   (interactive)
 265   (if hexl-in-save-buffer nil
 266     (set-buffer-modified-p (if (buffer-modified-p)
 267                                (save-excursion
 268                                  (let ((buf (generate-new-buffer " hexl"))
 269                                        (name (buffer-name))
 270                                        (file-name (buffer-file-name))
 271                                        (start (point-min))
 272                                        (end (point-max))
 273                                        modified)
 274                                    (set-buffer buf)
 275                                    (insert-buffer-substring name start end)
 276                                    (set-buffer name)
 277                                    (dehexlify-buffer)
 278                                    ;; Prevent infinite recursion.
 279                                    (let ((hexl-in-save-buffer t))
 280                                      (save-buffer))
 281                                    (setq modified (buffer-modified-p))
 282                                    (delete-region (point-min) (point-max))
 283                                    (insert-buffer-substring buf start end)
 284                                    (kill-buffer buf)
 285                                    modified))
 286                              (message "(No changes need to be saved)")
 287                              nil))
 288     ;; Return t to indicate we have saved t
 289     t))
 290
 291 ;;;###autoload
 292 (defun hexl-find-file (filename)
 293   "Edit file FILENAME in hexl-mode.
 294 Switch to a buffer visiting file FILENAME, creating one in none exists."
 295   (interactive
 296    (list
 297     (let ((completion-ignored-extensions nil))
 298       (read-file-name "Filename: " nil nil 'ret-must-match))))
 299   ;; Ignore the user's setting of default-major-mode.
 300   (let ((default-major-mode 'fundamental-mode))
 301     (find-file-literally filename))
 302   (if (not (eq major-mode 'hexl-mode))
 303       (hexl-mode)))
 304
 305 (defun hexl-mode-exit (&optional arg)
 306   "Exit Hexl mode, returning to previous mode.
 307 With arg, don't unhexlify buffer."
 308   (interactive "p")
 309   (if (or (eq arg 1) (not arg))
 310       (let ((modified (buffer-modified-p))
 311             (inhibit-read-only t)
 312             (original-point (1+ (hexl-current-address))))
 313         (dehexlify-buffer)
 314         (remove-hook 'write-contents-functions 'hexl-save-buffer t)
 315         (set-buffer-modified-p modified)
 316         (goto-char original-point)
 317         ;; Maybe adjust point for the removed CR characters.
 318         (when (eq (coding-system-eol-type buffer-file-coding-system) 1)
 319           (setq original-point (- original-point
 320                                   (count-lines (point-min) (point))))
 321           (or (bobp) (setq original-point (1+ original-point))))
 322         (goto-char original-point)))
 323
 324   (remove-hook 'after-revert-hook 'hexl-after-revert-hook t)
 325   (remove-hook 'change-major-mode-hook 'hexl-maybe-dehexlify-buffer t)
 326   (remove-hook 'post-command-hook 'hexl-follow-ascii-find t)
 327   (setq hexl-ascii-overlay nil)
 328
 329   (setq require-final-newline hexl-mode-old-require-final-newline)
 330   (setq mode-name hexl-mode-old-mode-name)
 331   (setq isearch-search-fun-function hexl-mode-old-isearch-search-fun-function)
 332   (use-local-map hexl-mode-old-local-map)
 333   (set-syntax-table hexl-mode-old-syntax-table)
 334   (setq major-mode hexl-mode-old-major-mode)
 335   (force-mode-line-update))
 336
 337 (defun hexl-maybe-dehexlify-buffer ()
 338   "Convert a hexl format buffer to binary.
 339 Ask the user for confirmation."
 340   (if (y-or-n-p "Convert contents back to binary format? ")
 341       (let ((modified (buffer-modified-p))
 342             (inhibit-read-only t)
 343             (original-point (1+ (hexl-current-address))))
 344         (dehexlify-buffer)
 345         (remove-hook 'write-contents-functions 'hexl-save-buffer t)
 346         (set-buffer-modified-p modified)
 347         (goto-char original-point))))
 348
 349 (defun hexl-current-address (&optional validate)
 350   "Return current hexl-address."
 351   (interactive)
 352   (let ((current-column (- (% (- (point) (point-min) -1) 68) 11))
 353         (hexl-address 0))
 354     (if (< current-column 0)
 355         (if validate
 356             (error "Point is not on a character in the file")
 357           (setq current-column 0)))
 358     (setq hexl-address
 359           (+ (* (/ (- (point) (point-min) -1) 68) 16)
 360              (if (>= current-column 41)
 361                  (- current-column 41)
 362                (/ (- current-column  (/ current-column 5)) 2))))
 363     (when (interactive-p)
 364       (message "Current address is %d" hexl-address))
 365     hexl-address))
 366
 367 (defun hexl-address-to-marker (address)
 368   "Return buffer position for ADDRESS."
 369   (interactive "nAddress: ")
 370   (+ (* (/ address 16) 68) 10 (point-min) (/ (* (% address 16) 5) 2)))
 371
 372 (defun hexl-goto-address (address)
 373   "Goto hexl-mode (decimal) address ADDRESS.
 374 Signal error if ADDRESS out of range."
 375   (interactive "nAddress: ")
 376   (if (or (< address 0) (> address hexl-max-address))
 377           (error "Out of hexl region"))
 378   (goto-char (hexl-address-to-marker address)))
 379
 380 (defun hexl-goto-hex-address (hex-address)
 381   "Go to hexl-mode address (hex string) HEX-ADDRESS.
 382 Signal error if HEX-ADDRESS is out of range."
 383   (interactive "sHex Address: ")
 384   (hexl-goto-address (hexl-hex-string-to-integer hex-address)))
 385
 386 (defun hexl-hex-string-to-integer (hex-string)
 387   "Return decimal integer for HEX-STRING."
 388   (interactive "sHex number: ")
 389   (let ((hex-num 0))
 390     (while (not (equal hex-string ""))
 391       (setq hex-num (+ (* hex-num 16)
 392                        (hexl-hex-char-to-integer (string-to-char hex-string))))
 393       (setq hex-string (substring hex-string 1)))
 394     hex-num))
 395
 396 (defun hexl-octal-string-to-integer (octal-string)
 397   "Return decimal integer for OCTAL-STRING."
 398   (interactive "sOctal number: ")
 399   (let ((oct-num 0))
 400     (while (not (equal octal-string ""))
 401       (setq oct-num (+ (* oct-num 8)
 402                        (hexl-oct-char-to-integer
 403                         (string-to-char octal-string))))
 404       (setq octal-string (substring octal-string 1)))
 405     oct-num))
 406
 407 ;; move point functions
 408
 409 (defun hexl-backward-char (arg)
 410   "Move to left ARG bytes (right if ARG negative) in hexl-mode."
 411   (interactive "p")
 412   (hexl-goto-address (- (hexl-current-address) arg)))
 413
 414 (defun hexl-forward-char (arg)
 415   "Move right ARG bytes (left if ARG negative) in hexl-mode."
 416   (interactive "p")
 417   (hexl-goto-address (+ (hexl-current-address) arg)))
 418
 419 (defun hexl-backward-short (arg)
 420   "Move to left ARG shorts (right if ARG negative) in hexl-mode."
 421   (interactive "p")
 422   (hexl-goto-address (let ((address (hexl-current-address)))
 423                        (if (< arg 0)
 424                            (progn
 425                              (setq arg (- arg))
 426                              (while (> arg 0)
 427                                (if (not (equal address (logior address 3)))
 428                                    (if (> address hexl-max-address)
 429                                        (progn
 430                                          (message "End of buffer.")
 431                                          (setq address hexl-max-address))
 432                                      (setq address (logior address 3)))
 433                                  (if (> address hexl-max-address)
 434                                      (progn
 435                                        (message "End of buffer.")
 436                                        (setq address hexl-max-address))
 437                                    (setq address (+ address 4))))
 438                                (setq arg (1- arg)))
 439                              (if (> address hexl-max-address)
 440                                  (progn
 441                                    (message "End of buffer.")
 442                                    (setq address hexl-max-address))
 443                                (setq address (logior address 3))))
 444                          (while (> arg 0)
 445                            (if (not (equal address (logand address -4)))
 446                                (setq address (logand address -4))
 447                              (if (not (equal address 0))
 448                                  (setq address (- address 4))
 449                                (message "Beginning of buffer.")))
 450                            (setq arg (1- arg))))
 451                        address)))
 452
 453 (defun hexl-forward-short (arg)
 454   "Move right ARG shorts (left if ARG negative) in hexl-mode."
 455   (interactive "p")
 456   (hexl-backward-short (- arg)))
 457
 458 (defun hexl-backward-word (arg)
 459   "Move to left ARG words (right if ARG negative) in hexl-mode."
 460   (interactive "p")
 461   (hexl-goto-address (let ((address (hexl-current-address)))
 462                        (if (< arg 0)
 463                            (progn
 464                              (setq arg (- arg))
 465                              (while (> arg 0)
 466                                (if (not (equal address (logior address 7)))
 467                                    (if (> address hexl-max-address)
 468                                        (progn
 469                                          (message "End of buffer.")
 470                                          (setq address hexl-max-address))
 471                                      (setq address (logior address 7)))
 472                                  (if (> address hexl-max-address)
 473                                      (progn
 474                                        (message "End of buffer.")
 475                                        (setq address hexl-max-address))
 476                                    (setq address (+ address 8))))
 477                                (setq arg (1- arg)))
 478                              (if (> address hexl-max-address)
 479                                  (progn
 480                                    (message "End of buffer.")
 481                                    (setq address hexl-max-address))
 482                                (setq address (logior address 7))))
 483                          (while (> arg 0)
 484                            (if (not (equal address (logand address -8)))
 485                                (setq address (logand address -8))
 486                              (if (not (equal address 0))
 487                                  (setq address (- address 8))
 488                                (message "Beginning of buffer.")))
 489                            (setq arg (1- arg))))
 490                        address)))
 491
 492 (defun hexl-forward-word (arg)
 493   "Move right ARG words (left if ARG negative) in hexl-mode."
 494   (interactive "p")
 495   (hexl-backward-word (- arg)))
 496
 497 (defun hexl-previous-line (arg)
 498   "Move vertically up ARG lines [16 bytes] (down if ARG negative) in hexl-mode.
 499 If there is byte at the target address move to the last byte in that line."
 500   (interactive "p")
 501   (hexl-next-line (- arg)))
 502
 503 (defun hexl-next-line (arg)
 504   "Move vertically down ARG lines [16 bytes] (up if ARG negative) in hexl-mode.
 505 If there is no byte at the target address move to the last byte in that line."
 506   (interactive "p")
 507   (hexl-goto-address (let ((address (+ (hexl-current-address) (* arg 16))))
 508                        (if (and (< arg 0) (< address 0))
 509                                 (progn (message "Out of hexl region.")
 510                                        (setq address
 511                                              (% (hexl-current-address) 16)))
 512                          (if (and (> address hexl-max-address)
 513                                   (< (% hexl-max-address 16) (% address 16)))
 514                              (setq address hexl-max-address)
 515                            (if (> address hexl-max-address)
 516                                (progn (message "Out of hexl region.")
 517                                       (setq
 518                                        address
 519                                        (+ (logand hexl-max-address -16)
 520                                           (% (hexl-current-address) 16)))))))
 521                        address)))
 522
 523 (defun hexl-beginning-of-buffer (arg)
 524   "Move to the beginning of the hexl buffer.
 525 Leaves `hexl-mark' at previous position.
 526 With prefix arg N, puts point N bytes of the way from the true beginning."
 527   (interactive "p")
 528   (push-mark (point))
 529   (hexl-goto-address (+ 0 (1- arg))))
 530
 531 (defun hexl-end-of-buffer (arg)
 532   "Go to `hexl-max-address' minus ARG."
 533   (interactive "p")
 534   (push-mark (point))
 535   (hexl-goto-address (- hexl-max-address (1- arg))))
 536
 537 (defun hexl-beginning-of-line ()
 538   "Goto beginning of line in hexl mode."
 539   (interactive)
 540   (goto-char (+ (* (/ (point) 68) 68) 11)))
 541
 542 (defun hexl-end-of-line ()
 543   "Goto end of line in hexl mode."
 544   (interactive)
 545   (hexl-goto-address (let ((address (logior (hexl-current-address) 15)))
 546                        (if (> address hexl-max-address)
 547                            (setq address hexl-max-address))
 548                        address)))
 549
 550 (defun hexl-scroll-down (arg)
 551   "Scroll hexl buffer window upward ARG lines; or near full window if no ARG."
 552   (interactive "P")
 553   (if (null arg)
 554       (setq arg (1- (window-height)))
 555     (setq arg (prefix-numeric-value arg)))
 556   (hexl-scroll-up (- arg)))
 557
 558 (defun hexl-scroll-up (arg)
 559   "Scroll hexl buffer window upward ARG lines; or near full window if no ARG.
 560 If there's no byte at the target address, move to the first or last line."
 561   (interactive "P")
 562   (if (null arg)
 563       (setq arg (1- (window-height)))
 564     (setq arg (prefix-numeric-value arg)))
 565   (let* ((movement (* arg 16))
 566          (address (hexl-current-address))
 567          (dest (+ address movement)))
 568     (cond
 569      ;; If possible, try to stay at the same offset from the beginning
 570      ;; of the 16-byte group, even if we move to the first or last
 571      ;; group.
 572      ((and (> dest hexl-max-address)
 573            (>= (% hexl-max-address 16) (% address 16)))
 574       (setq dest (+ (logand hexl-max-address -16) (% address 16))))
 575      ((> dest hexl-max-address)
 576       (setq dest hexl-max-address))
 577      ((< dest 0)
 578       (setq dest (% address 16))))
 579     (if (/= dest (+ address movement))
 580         (message "Out of hexl region."))
 581     (hexl-goto-address dest)
 582     (recenter 0)))
 583
 584 (defun hexl-beginning-of-1k-page ()
 585   "Go to beginning of 1k boundary."
 586   (interactive)
 587   (hexl-goto-address (logand (hexl-current-address) -1024)))
 588
 589 (defun hexl-end-of-1k-page ()
 590   "Go to end of 1k boundary."
 591   (interactive)
 592   (hexl-goto-address (let ((address (logior (hexl-current-address) 1023)))
 593                        (if (> address hexl-max-address)
 594                            (setq address hexl-max-address))
 595                        address)))
 596
 597 (defun hexl-beginning-of-512b-page ()
 598   "Go to beginning of 512 byte boundary."
 599   (interactive)
 600   (hexl-goto-address (logand (hexl-current-address) -512)))
 601
 602 (defun hexl-end-of-512b-page ()
 603   "Go to end of 512 byte boundary."
 604   (interactive)
 605   (hexl-goto-address (let ((address (logior (hexl-current-address) 511)))
 606                        (if (> address hexl-max-address)
 607                            (setq address hexl-max-address))
 608                        address)))
 609
 610 (defun hexl-quoted-insert (arg)
 611   "Read next input character and insert it.
 612 Useful for inserting control characters and non-ASCII characters given their
 613 numerical code.
 614 You may also type octal digits, to insert a character with that code."
 615   (interactive "p")
 616   (hexl-insert-multibyte-char (read-quoted-char) arg))
 617
 618 ;00000000: 0011 2233 4455 6677 8899 aabb ccdd eeff  0123456789ABCDEF
 619
 620 ;;;###autoload
 621 (defun hexlify-buffer ()
 622   "Convert a binary buffer to hexl format.
 623 This discards the buffer's undo information."
 624   (interactive)
 625   (and buffer-undo-list
 626        (or (y-or-n-p "Converting to hexl format discards undo info; ok? ")
 627            (error "Aborted")))
 628   (setq buffer-undo-list nil)
 629   ;; Don't decode text in the ASCII part of `hexl' program output.
 630   (let ((coding-system-for-read 'raw-text)
 631         (coding-system-for-write buffer-file-coding-system)
 632         (buffer-undo-list t))
 633     (apply 'call-process-region (point-min) (point-max)
 634            (expand-file-name hexl-program exec-directory)
 635            t t nil (split-string hexl-options))
 636     (if (> (point) (hexl-address-to-marker hexl-max-address))
 637         (hexl-goto-address hexl-max-address))))
 638
 639 (defun dehexlify-buffer ()
 640   "Convert a hexl format buffer to binary.
 641 This discards the buffer's undo information."
 642   (interactive)
 643   (and buffer-undo-list
 644        (or (y-or-n-p "Converting from hexl format discards undo info; ok? ")
 645            (error "Aborted")))
 646   (setq buffer-undo-list nil)
 647   (let ((coding-system-for-write 'raw-text)
 648         (coding-system-for-read buffer-file-coding-system)
 649         (buffer-undo-list t))
 650     (apply 'call-process-region (point-min) (point-max)
 651            (expand-file-name hexl-program exec-directory)
 652            t t nil "-de" (split-string hexl-options))))
 653
 654 (defun hexl-char-after-point ()
 655   "Return char for ASCII hex digits at point."
 656   (hexl-htoi (char-after (point))
 657              (char-after (1+ (point)))))
 658
 659 (defun hexl-htoi (lh rh)
 660   "Hex (char) LH (char) RH to integer."
 661     (+ (* (hexl-hex-char-to-integer lh) 16)
 662        (hexl-hex-char-to-integer rh)))
 663
 664 (defun hexl-hex-char-to-integer (character)
 665   "Take a char and return its value as if it was a hex digit."
 666   (if (and (>= character ?0) (<= character ?9))
 667       (- character ?0)
 668     (let ((ch (logior character 32)))
 669       (if (and (>= ch ?a) (<= ch ?f))
 670           (- ch (- ?a 10))
 671         (error "Invalid hex digit `%c'" ch)))))
 672
 673 (defun hexl-oct-char-to-integer (character)
 674   "Take a char and return its value as if it was a octal digit."
 675   (if (and (>= character ?0) (<= character ?7))
 676       (- character ?0)
 677     (error "Invalid octal digit `%c'" character)))
 678
 679 (defun hexl-printable-character (ch)
 680   "Return a displayable string for character CH."
 681   (format "%c" (if hexl-iso
 682                    (if (or (< ch 32) (and (>= ch 127) (< ch 160)))
 683                        46
 684                      ch)
 685                  (if (or (< ch 32) (>= ch 127))
 686                      46
 687                    ch))))
 688
 689 (defun hexl-insert-multibyte-char (ch num)
 690   "Insert a possibly multibyte character CH NUM times.
 691
 692 Non-ASCII characters are first encoded with `buffer-file-coding-system',
 693 and their encoded form is inserted byte by byte."
 694   (let ((charset (char-charset ch))
 695         (coding (if (or (null buffer-file-coding-system)
 696                         ;; coding-system-type equals t means undecided.
 697                         (eq (coding-system-type buffer-file-coding-system) t))
 698                     default-buffer-file-coding-system
 699                   buffer-file-coding-system)))
 700     (cond ((and (> ch 0) (< ch 256))
 701            (hexl-insert-char ch num))
 702           ((eq charset 'unknown)
 703            (error
 704             "0x%x -- invalid character code; use \\[hexl-insert-hex-string]"
 705             ch))
 706           (t
 707            (let ((encoded (encode-coding-char ch coding))
 708                  (internal (string-as-unibyte (char-to-string ch)))
 709                  internal-hex)
 710              ;; If encode-coding-char returns nil, it means our character
 711              ;; cannot be safely encoded with buffer-file-coding-system.
 712              ;; In that case, we offer to insert the internal representation
 713              ;; of that character, byte by byte.
 714              (when (null encoded)
 715                (setq internal-hex
 716                      (mapconcat (function (lambda (c) (format "%x" c)))
 717                                 internal " "))
 718                (if (yes-or-no-p
 719                     (format
 720                      "Insert char 0x%x's internal representation \"%s\"? "
 721                      ch internal-hex))
 722                    (setq encoded internal)
 723                  (error
 724                   "Can't encode `0x%x' with this buffer's coding system; try \\[hexl-insert-hex-string]"
 725                   ch)))
 726              (while (> num 0)
 727                (mapc
 728                 (function (lambda (c) (hexl-insert-char c 1))) encoded)
 729                (setq num (1- num))))))))
 730
 731 (defun hexl-self-insert-command (arg)
 732   "Insert this character.
 733 Interactively, with a numeric argument, insert this character that many times.
 734
 735 Non-ASCII characters are first encoded with `buffer-file-coding-system',
 736 and their encoded form is inserted byte by byte."
 737   (interactive "p")
 738   (hexl-insert-multibyte-char last-command-char arg))
 739
 740 (defun hexl-insert-char (ch num)
 741   "Insert the character CH NUM times in a hexl buffer.
 742
 743 CH must be a unibyte character whose value is between 0 and 255."
 744   (if (or (< ch 0) (> ch 255))
 745       (error "Invalid character 0x%x -- must be in the range [0..255]"))
 746   (let ((address (hexl-current-address t)))
 747     (while (> num 0)
 748       (let ((hex-position
 749              (+ (* (/ address 16) 68)
 750                 10 (point-min)
 751                 (* 2 (% address 16))
 752                 (/ (% address 16) 2)))
 753             (ascii-position
 754              (+ (* (/ address 16) 68) 51 (point-min) (% address 16)))
 755             at-ascii-position)
 756         (if (= (point) ascii-position)
 757             (setq at-ascii-position t))
 758         (goto-char hex-position)
 759         (delete-char 2)
 760         (insert (format "%02x" ch))
 761         (goto-char ascii-position)
 762         (delete-char 1)
 763         (insert (hexl-printable-character ch))
 764         (or (eq address hexl-max-address)
 765             (setq address (1+ address)))
 766         (hexl-goto-address address)
 767         (if at-ascii-position
 768             (progn
 769               (beginning-of-line)
 770               (forward-char 51)
 771               (forward-char (% address 16)))))
 772       (setq num (1- num)))))
 773
 774 ;; hex conversion
 775
 776 (defun hexl-insert-hex-char (arg)
 777   "Insert a character given by its hexadecimal code ARG times at point."
 778   (interactive "p")
 779   (let ((num (hexl-hex-string-to-integer (read-string "Hex number: "))))
 780     (if (< num 0)
 781         (error "Hex number out of range")
 782       (hexl-insert-multibyte-char num arg))))
 783
 784 (defun hexl-insert-hex-string (str arg)
 785   "Insert hexadecimal string STR at point ARG times.
 786 Embedded whitespace, dashes, and periods in the string are ignored."
 787   (interactive "sHex string: \np")
 788   (setq str (replace-regexp-in-string "[- \t.]" "" str))
 789   (let ((chars '()))
 790     (let ((len (length str))
 791           (idx 0))
 792       (if (eq (logand len 1) 1)
 793           (let ((num (hexl-hex-string-to-integer (substring str 0 1))))
 794             (setq chars (cons num chars))
 795             (setq idx 1)))
 796       (while (< idx len)
 797         (let* ((nidx (+ idx 2))
 798                (num (hexl-hex-string-to-integer (substring str idx nidx))))
 799           (setq chars (cons num chars))
 800           (setq idx nidx))))
 801     (setq chars (nreverse chars))
 802     (while (> arg 0)
 803       (let ((chars chars))
 804         (while chars
 805           (hexl-insert-char (car chars) 1)
 806           (setq chars (cdr chars))))
 807       (setq arg (- arg 1)))))
 808
 809 (defun hexl-insert-decimal-char (arg)
 810   "Insert a character given by its decimal code ARG times at point."
 811   (interactive "p")
 812   (let ((num (string-to-int (read-string "Decimal Number: "))))
 813     (if (< num 0)
 814         (error "Decimal number out of range")
 815       (hexl-insert-multibyte-char num arg))))
 816
 817 (defun hexl-insert-octal-char (arg)
 818   "Insert a character given by its octal code ARG times at point."
 819   (interactive "p")
 820   (let ((num (hexl-octal-string-to-integer (read-string "Octal Number: "))))
 821     (if (< num 0)
 822         (error "Decimal number out of range")
 823       (hexl-insert-multibyte-char num arg))))
 824
 825 (defun hexl-follow-ascii (&optional arg)
 826   "Toggle following ASCII in Hexl buffers.
 827 With prefix ARG, turn on following if and only if ARG is positive.
 828 When following is enabled, the ASCII character corresponding to the
 829 element under the point is highlighted.
 830 Customize the variable `hexl-follow-ascii' to disable this feature."
 831   (interactive "P")
 832   (let ((on-p (if arg
 833                   (> (prefix-numeric-value arg) 0)
 834                (not hexl-ascii-overlay))))
 835
 836     (if on-p
 837       ;; turn it on
 838       (if (not hexl-ascii-overlay)
 839           (progn
 840             (setq hexl-ascii-overlay (make-overlay 1 1)
 841                   hexl-follow-ascii t)
 842             (overlay-put hexl-ascii-overlay 'face 'highlight)
 843             (add-hook 'post-command-hook 'hexl-follow-ascii-find nil t)))
 844       ;; turn it off
 845       (if hexl-ascii-overlay
 846           (progn
 847             (delete-overlay hexl-ascii-overlay)
 848             (setq hexl-ascii-overlay nil
 849                   hexl-follow-ascii nil)
 850             (remove-hook 'post-command-hook 'hexl-follow-ascii-find t)
 851             )))))
 852
 853 (defun hexl-follow-ascii-find ()
 854   "Find and highlight the ASCII element corresponding to current point."
 855   (let ((pos (+ 51
 856                 (- (point) (current-column))
 857                 (mod (hexl-current-address) 16))))
 858     (move-overlay hexl-ascii-overlay pos (1+ pos))
 859     ))
 860
 861 ;; startup stuff.
 862
 863 (if hexl-mode-map
 864     nil
 865   (setq hexl-mode-map (make-keymap))
 866   ;; Make all self-inserting keys go through hexl-self-insert-command,
 867   ;; because we need to convert them to unibyte characters before
 868   ;; inserting them into the buffer.
 869   (define-key hexl-mode-map [remap self-insert-command] 'hexl-self-insert-command)
 870
 871   (define-key hexl-mode-map "\C-m" 'hexl-self-insert-command)
 872   (define-key hexl-mode-map [left] 'hexl-backward-char)
 873   (define-key hexl-mode-map [right] 'hexl-forward-char)
 874   (define-key hexl-mode-map [up] 'hexl-previous-line)
 875   (define-key hexl-mode-map [down] 'hexl-next-line)
 876   (define-key hexl-mode-map [M-left] 'hexl-backward-short)
 877   (define-key hexl-mode-map [M-right] 'hexl-forward-short)
 878   (define-key hexl-mode-map [next] 'hexl-scroll-up)
 879   (define-key hexl-mode-map [prior] 'hexl-scroll-down)
 880   (define-key hexl-mode-map [home] 'hexl-beginning-of-line)
 881   (define-key hexl-mode-map [end] 'hexl-end-of-line)
 882   (define-key hexl-mode-map [C-home] 'hexl-beginning-of-buffer)
 883   (define-key hexl-mode-map [C-end] 'hexl-end-of-buffer)
 884   (define-key hexl-mode-map [deletechar] 'undefined)
 885   (define-key hexl-mode-map [deleteline] 'undefined)
 886   (define-key hexl-mode-map [insertline] 'undefined)
 887   (define-key hexl-mode-map [S-delete] 'undefined)
 888   (define-key hexl-mode-map "\177" 'undefined)
 889
 890   (define-key hexl-mode-map "\C-a" 'hexl-beginning-of-line)
 891   (define-key hexl-mode-map "\C-b" 'hexl-backward-char)
 892   (define-key hexl-mode-map "\C-d" 'undefined)
 893   (define-key hexl-mode-map "\C-e" 'hexl-end-of-line)
 894   (define-key hexl-mode-map "\C-f" 'hexl-forward-char)
 895
 896   (if (not (eq (key-binding (char-to-string help-char)) 'help-command))
 897       (define-key hexl-mode-map (char-to-string help-char) 'undefined))
 898
 899   (define-key hexl-mode-map "\C-k" 'undefined)
 900   (define-key hexl-mode-map "\C-n" 'hexl-next-line)
 901   (define-key hexl-mode-map "\C-o" 'undefined)
 902   (define-key hexl-mode-map "\C-p" 'hexl-previous-line)
 903   (define-key hexl-mode-map "\C-q" 'hexl-quoted-insert)
 904   (define-key hexl-mode-map "\C-t" 'undefined)
 905   (define-key hexl-mode-map "\C-v" 'hexl-scroll-up)
 906   (define-key hexl-mode-map "\C-w" 'undefined)
 907   (define-key hexl-mode-map "\C-y" 'undefined)
 908
 909   (fset 'hexl-ESC-prefix (copy-keymap 'ESC-prefix))
 910   (define-key hexl-mode-map "\e" 'hexl-ESC-prefix)
 911   (define-key hexl-mode-map "\e\C-a" 'hexl-beginning-of-512b-page)
 912   (define-key hexl-mode-map "\e\C-b" 'hexl-backward-short)
 913   (define-key hexl-mode-map "\e\C-d" 'hexl-insert-decimal-char)
 914   (define-key hexl-mode-map "\e\C-e" 'hexl-end-of-512b-page)
 915   (define-key hexl-mode-map "\e\C-f" 'hexl-forward-short)
 916   (define-key hexl-mode-map "\e\C-i" 'undefined)
 917   (define-key hexl-mode-map "\e\C-j" 'undefined)
 918   (define-key hexl-mode-map "\e\C-k" 'undefined)
 919   (define-key hexl-mode-map "\e\C-o" 'hexl-insert-octal-char)
 920   (define-key hexl-mode-map "\e\C-q" 'undefined)
 921   (define-key hexl-mode-map "\e\C-t" 'undefined)
 922   (define-key hexl-mode-map "\e\C-x" 'hexl-insert-hex-char)
 923   (define-key hexl-mode-map "\eb" 'hexl-backward-word)
 924   (define-key hexl-mode-map "\ec" 'undefined)
 925   (define-key hexl-mode-map "\ed" 'undefined)
 926   (define-key hexl-mode-map "\ef" 'hexl-forward-word)
 927   (define-key hexl-mode-map "\eg" 'hexl-goto-hex-address)
 928   (define-key hexl-mode-map "\ei" 'undefined)
 929   (define-key hexl-mode-map "\ej" 'hexl-goto-address)
 930   (define-key hexl-mode-map "\ek" 'undefined)
 931   (define-key hexl-mode-map "\el" 'undefined)
 932   (define-key hexl-mode-map "\eq" 'undefined)
 933   (define-key hexl-mode-map "\es" 'undefined)
 934   (define-key hexl-mode-map "\et" 'undefined)
 935   (define-key hexl-mode-map "\eu" 'undefined)
 936   (define-key hexl-mode-map "\ev" 'hexl-scroll-down)
 937   (define-key hexl-mode-map "\ey" 'undefined)
 938   (define-key hexl-mode-map "\ez" 'undefined)
 939   (define-key hexl-mode-map "\e<" 'hexl-beginning-of-buffer)
 940   (define-key hexl-mode-map "\e>" 'hexl-end-of-buffer)
 941
 942   (fset 'hexl-C-c-prefix (copy-keymap mode-specific-map))
 943   (define-key hexl-mode-map "\C-c" 'hexl-C-c-prefix)
 944   (define-key hexl-mode-map "\C-c\C-c" 'hexl-mode-exit)
 945
 946   (fset 'hexl-C-x-prefix (copy-keymap 'Control-X-prefix))
 947   (define-key hexl-mode-map "\C-x" 'hexl-C-x-prefix)
 948   (define-key hexl-mode-map "\C-x[" 'hexl-beginning-of-1k-page)
 949   (define-key hexl-mode-map "\C-x]" 'hexl-end-of-1k-page)
 950   (define-key hexl-mode-map "\C-x\C-p" 'undefined)
 951   (define-key hexl-mode-map "\C-x\C-s" 'hexl-save-buffer)
 952   (define-key hexl-mode-map "\C-x\C-t" 'undefined))
 953
 954 (provide 'hexl)
 955
 956 ;;; hexl.el ends here