Re: address@hidden: hexl-max-address in hexl-mode is incorrect]

[Stefan Monnier]

> -      (if (not (or (eq arg 1) (not arg)))
> -          ;; if no argument then we guess at hexl-max-address
> -          (setq max-address (+ (* (/ (1- (buffer-size)) 68) 16) 15))

This removes a special case which seems unused but not uninteresting.
More specifically it hints at a better solution to our problem.
See patch below.

Note that it doesn't address the similar problem with `original-point'.
This one may require the use of encode-coding-string.
Also it seems that hexl-mode doesn't like to be called in an empty buffer
and my patch doesn't fix that part.


        Stefan


--- orig/lisp/hexl.el
+++ mod/lisp/hexl.el
@@ -207,31 +207,26 @@
   (unless (eq major-mode 'hexl-mode)
     (let ((modified (buffer-modified-p))
          (inhibit-read-only t)
-         (original-point (- (point) (point-min)))
-         max-address)
+         (original-point (- (point) (point-min))))
       (and (eobp) (not (bobp))
           (setq original-point (1- original-point)))
-      (if (not (or (eq arg 1) (not arg)))
-         ;; if no argument then we guess at hexl-max-address
-          (setq max-address (+ (* (/ (1- (buffer-size)) 68) 16) 15))
-        (setq max-address (1- (buffer-size)))
+      ;; If `hexl-mode' is invoked with an argument the buffer is assumed to
+      ;; be in hexl format.
+      (when (memq arg '(1 nil))
        ;; If the buffer's EOL type is -dos, we need to account for
        ;; extra CR characters added when hexlify-buffer writes the
        ;; buffer to a file.
        (when (eq (coding-system-eol-type buffer-file-coding-system) 1)
-         (setq max-address (+ (count-lines (point-min) (point-max))
-                              max-address))
-         ;; But if there's no newline at the last line, we are off by
-         ;; one; adjust.
-         (or (eq (char-before (point-max)) ?\n)
-             (setq max-address (1- max-address)))
-         (setq original-point (+ (count-lines (point-min) (point))
+          (setq original-point (+ (count-lines (point-min) (point))
                                  original-point))
          (or (bolp) (setq original-point (1- original-point))))
         (hexlify-buffer)
         (restore-buffer-modified-p modified))
-      (make-local-variable 'hexl-max-address)
-      (setq hexl-max-address max-address)
+      (set (make-local-variable 'hexl-max-address)
+           (let* ((full-lines (/ (buffer-size) 68))
+                  (last-line (% (buffer-size) 68))
+                  (last-line-bytes (% last-line 52)))
+             (+ last-line-bytes (* full-lines 16) -1)))
       (condition-case nil
          (hexl-goto-address original-point)
        (error nil)))
@@ -713,7 +708,9 @@
            ;; Manually encode the args, otherwise they're encoded using
            ;; coding-system-for-write (i.e. buffer-file-coding-system) which
            ;; may not be what we want (e.g. utf-16 on a non-utf-16 system).
-           (mapcar (lambda (s) (encode-coding-string s locale-coding-system))
+           (mapcar (lambda (s)
+                     (if (unibyte-string-p s) s
+                       (encode-coding-string s locale-coding-system)))
                    (split-string hexl-options)))
     (if (> (point) (hexl-address-to-marker hexl-max-address))
        (hexl-goto-address hexl-max-address))))