diff options
| -rw-r--r-- | lisp/hexl.el | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/lisp/hexl.el b/lisp/hexl.el index daa4dc79c9c..ace1dfb08f9 100644 --- a/lisp/hexl.el +++ b/lisp/hexl.el @@ -88,6 +88,11 @@ and \"-de\" when dehexlifying a buffer." :type 'string :group 'hexl) +(defcustom hexl-follow-ascii t + "If non-nil then highlight the ASCII character corresponding to point." + :type 'boolean + :group 'hexl) + (defvar hexl-max-address 0 "Maximum offset into hexl buffer.") @@ -100,6 +105,10 @@ and \"-de\" when dehexlifying a buffer." (defvar hexl-mode-old-require-final-newline) (defvar hexl-mode-old-syntax-table) +(defvar hexl-ascii-overlay nil + "Overlay used to highlight ASCII element corresponding to current point.") +(make-variable-buffer-local 'hexl-ascii-overlay) + ;; routines (put 'hexl-mode 'mode-class 'special) @@ -229,7 +238,9 @@ You can use \\[hexl-find-file] to visit a file in hexl-mode. (add-hook 'after-revert-hook 'hexl-after-revert-hook nil t) (make-local-hook 'change-major-mode-hook) - (add-hook 'change-major-mode-hook 'hexl-maybe-dehexlify-buffer nil t)) + (add-hook 'change-major-mode-hook 'hexl-maybe-dehexlify-buffer nil t) + + (if hexl-follow-ascii (hexl-follow-ascii 1))) (run-hooks 'hexl-mode-hook)) (defun hexl-after-revert-hook () @@ -703,6 +714,44 @@ This discards the buffer's undo information." (error "Decimal number out of range") (hexl-insert-char num arg)))) +(defun hexl-follow-ascii (&optional arg) + "Toggle following ASCII in Hexl buffers. +With prefix ARG, turn on following if and only if ARG is positive. +When following is enabled, the ASCII character corresponding to the +element under the point is highlighted. +Customize the variable `hexl-follow-ascii' to disable this feature." + (interactive "P") + (let ((on-p (if arg + (> (prefix-numeric-value arg) 0) + (not hexl-ascii-overlay)))) + + (make-local-hook 'post-command-hook) + + (if on-p + ;; turn it on + (if (not hexl-ascii-overlay) + (progn + (setq hexl-ascii-overlay (make-overlay 1 1) + hexl-follow-ascii t) + (overlay-put hexl-ascii-overlay 'face 'highlight) + (add-hook 'post-command-hook 'hexl-follow-ascii-find nil t))) + ;; turn it off + (if hexl-ascii-overlay + (progn + (delete-overlay hexl-ascii-overlay) + (setq hexl-ascii-overlay nil + hexl-follow-ascii nil) + (remove-hook 'post-command-hook 'hexl-follow-ascii-find t) + ))))) + +(defun hexl-follow-ascii-find () + "Find and highlight the ASCII element corresponding to current point." + (let ((pos (+ 51 + (- (point) (current-column)) + (mod (hexl-current-address) 16)))) + (move-overlay hexl-ascii-overlay pos (1+ pos)) + )) + ;; startup stuff. (if hexl-mode-map |