(tar-file-name-coding-system): New variable. Make

it permanent-local.p
(tar-header-block-tokenize): Decode filename and linkname by
tar-file-name-coding-system.
(tar-header-block-checksum): Call multibyte-char-to-unibyte to get
the byte value of eight-bit chars.
(tar-summarize-buffer): Call set-buffer-multibyte with METHOD
`to'.  Delete unnecessary call of position-bytes.
(tar-mode): Set tar-file-name-coding-system.  Delete unnecessary
call of position-bytes.
(tar-extract): Simplified by calling decode-coding-region with
DESTINATION argument.  Don't toggle multibyteness of tar buffer.
(tar-copy): Don't toggle multibyteness of tar buffer.
(tar-expunge): Likewise.
(tar-clear-modification-flags): Delete unnecessary call of
position-bytes.
(tar-rename-entry): Call tar-alter-one-field with encoded new
name.
(tar-alter-one-field): Don't toggle multibyteness of tar buffer.
Convert new-data-string by string-to-multibyte before inserting
it.
(tar-subfile-save-buffer): Don't toggle multibyteness of tar
buffer.  Simplified by calling encoding-coding-region with
DESTINATION argument.
(tar-mode-write-file): Delete unnecessary call of
byte-to-position.

1 files changed, 75 insertions, 107 deletions

diff --git a/lisp/tar-mode.el b/lisp/tar-mode.el
index 2bfd75c7630..bd10737b548 100644
--- a/lisp/tar-mode.el
+++ b/lisp/tar-mode.el
@@ -129,16 +129,17 @@ This information is useful, but it takes screen space away from file names."
   :group 'tar)
 
 (defvar tar-parse-info nil)
-;; Be sure that this variable holds byte position, not char position.
 (defvar tar-header-offset nil)
 (defvar tar-superior-buffer nil)
 (defvar tar-superior-descriptor nil)
 (defvar tar-subfile-mode nil)
+(defvar tar-file-name-coding-system nil)
 
 (put 'tar-parse-info 'permanent-local t)
 (put 'tar-header-offset 'permanent-local t)
 (put 'tar-superior-buffer 'permanent-local t)
 (put 'tar-superior-descriptor 'permanent-local t)
+(put 'tar-file-name-coding-system 'permanent-local t)
 
 (defmacro tar-setf (form val)
   "A mind-numbingly simple implementation of setf."
@@ -231,11 +232,10 @@ write-date, checksum, link-type, and link-name."
            (setq linkname (substring string tar-link-offset link-end))
            (if default-enable-multibyte-characters
                (setq name
-                     (decode-coding-string name (or file-name-coding-system
-                                                    'undecided))
+                     (decode-coding-string name tar-file-name-coding-system)
                      linkname
-                     (decode-coding-string linkname (or file-name-coding-system
-                                                        'undecided))))
+                     (decode-coding-string linkname
+                                           tar-file-name-coding-system)))
            (if (and (null link-p) (string-match "/$" name)) (setq link-p 5)) ; directory
            (make-tar-header
              name
@@ -302,11 +302,11 @@ write-date, checksum, link-type, and link-name."
     ;; Add up all of the characters except the ones in the checksum field.
     ;; Add that field as if it were filled with spaces.
     (while (< i chk-field-start)
-      (setq sum (+ sum (aref string i))
+      (setq sum (+ sum (multibyte-char-to-unibyte (aref string i)))
             i (1+ i)))
     (setq i chk-field-end)
     (while (< i 512)
-      (setq sum (+ sum (aref string i))
+      (setq sum (+ sum (multibyte-char-to-unibyte (aref string i)))
             i (1+ i)))
     (+ sum (* 32 8))))
 
@@ -434,15 +434,13 @@ is visible (and the real data of the buffer is hidden)."
               (cons (tar-header-block-summarize (tar-desc-tokens tar-desc))
                     (cons "\n"
                           summaries))))
+      (if default-enable-multibyte-characters
+          (set-buffer-multibyte t 'to))
       (let ((total-summaries (apply 'concat summaries)))
-        (if (multibyte-string-p total-summaries)
-            (set-buffer-multibyte t))
         (insert total-summaries))
       (make-local-variable 'tar-header-offset)
       (setq tar-header-offset (point))
       (narrow-to-region 1 tar-header-offset)
-      (if enable-multibyte-characters
-          (setq tar-header-offset (position-bytes tar-header-offset)))
       (set-buffer-modified-p nil))))
 
 (defvar tar-mode-map nil "*Local keymap for Tar mode listings.")
@@ -553,13 +551,17 @@ See also: variables `tar-update-datestamp' and `tar-anal-blocksize'.
   (set (make-local-variable 'revert-buffer-function) 'tar-mode-revert)
   (set (make-local-variable 'local-enable-local-variables) nil)
   (set (make-local-variable 'next-line-add-newlines) nil)
+  (set (make-local-variable 'tar-file-name-coding-system)
+       (or file-name-coding-system
+           default-file-name-coding-system
+           locale-coding-system))
   ;; Prevent loss of data when saving the file.
   (set (make-local-variable 'file-precious-flag) t)
   (auto-save-mode 0)
   (set (make-local-variable 'write-contents-hooks) '(tar-mode-write-file))
   (widen)
   (if (and (boundp 'tar-header-offset) tar-header-offset)
-      (narrow-to-region 1 (byte-to-position tar-header-offset))
+      (narrow-to-region 1 tar-header-offset)
     (tar-summarize-buffer)
     (tar-next-line 0)))
 
@@ -681,61 +683,40 @@ appear on disk when you save the tar-file's buffer."
                                   ;; `:' is not allowed on Windows
                                   (concat tarname "!" name)))
            (buffer (get-file-buffer new-buffer-file-name))
-           (just-created nil))
+           (just-created nil)
+           (pos (point)))
       (unless buffer
         (setq buffer (generate-new-buffer bufname))
         (setq bufname (buffer-name buffer))
         (setq just-created t)
         (unwind-protect
-            (progn
-              (widen)
-              (set-buffer-multibyte nil)
+            (let (coding)
+              (narrow-to-region start end)
+              (goto-char start)
+              (setq coding (or coding-system-for-read
+                               (and set-auto-coding-function
+                                    (funcall set-auto-coding-function
+                                             name (point-max)))))
+              (if (or (not coding)
+                      (eq (coding-system-type coding) 'undecided))
+                  (setq coding (detect-coding-region start end t)))
+              (if (eq (coding-system-type coding) 'undecided)
+                  (setq coding
+                        (coding-system-change-text-conversion coding
+                                                              'us-ascii)))
               (save-excursion
                 (set-buffer buffer)
-                (if enable-multibyte-characters
-                    (progn
-                      ;; We must avoid unibyte->multibyte conversion.
-                      (set-buffer-multibyte nil)
-                      (insert-buffer-substring tar-buffer start end)
-                      (set-buffer-multibyte t))
-                  (insert-buffer-substring tar-buffer start end))
+                (if (and enable-multibyte-characters
+                         (eq (coding-system-type 'raw-text) coding))
+                    (set-buffer-multibyte nil))
                 (goto-char (point-min))
                 (setq buffer-file-name new-buffer-file-name)
                 (setq buffer-file-truename
-                      (abbreviate-file-name buffer-file-name))
-                ;; We need to mimic the parts of insert-file-contents
-                ;; which determine the coding-system and decode the text.
-                (let ((coding
-                       (or coding-system-for-read
-                           (and set-auto-coding-function
-                                (save-excursion
-                                  (funcall set-auto-coding-function
-                                           name (- (point-max) (point)))))))
-                      (multibyte enable-multibyte-characters)
-                      (detected (detect-coding-region
-                                 1 (min 16384 (point-max)) t)))
-                  (if coding
-                      (or (numberp (coding-system-eol-type coding))
-                          (setq coding (coding-system-change-eol-conversion
-                                        coding
-                                        (coding-system-eol-type detected))))
-                    (setq coding
-                          (or (find-new-buffer-file-coding-system detected)
-                              (let ((file-coding
-                                     (find-operation-coding-system
-                                      'insert-file-contents buffer-file-name)))
-                                (if (consp file-coding)
-                                    (setq file-coding (car file-coding))
-                                  file-coding)))))
-                  (if (or (eq coding 'no-conversion)
-                          (eq (coding-system-type coding) 5))
-                      (setq multibyte (set-buffer-multibyte nil)))
-                  (or multibyte
-                      (setq coding
-                            (coding-system-change-text-conversion
-                             coding 'raw-text)))
-                  (decode-coding-region 1 (point-max) coding)
-                  (set-buffer-file-coding-system coding))
+                      (abbreviate-file-name buffer-file-name)))
+              (decode-coding-region start end coding buffer)
+              (save-excursion
+                (set-buffer buffer)
+                (goto-char (point-min))
                 ;; Set the default-directory to the dir of the
                 ;; superior buffer. 
                 (setq default-directory
@@ -753,7 +734,7 @@ appear on disk when you save the tar-file's buffer."
                 (tar-subfile-mode 1))
               (set-buffer tar-buffer))
           (narrow-to-region 1 tar-header-offset)
-          (set-buffer-multibyte tar-buffer-multibyte)))
+          (goto-char pos)))
       (if view-p
           (view-buffer buffer (and just-created 'kill-buffer))
         (if (eq other-window-p 'display)
@@ -810,7 +791,6 @@ the current tar-entry."
          (size (tar-header-size tokens))
          (start (+ (tar-desc-data-start descriptor) tar-header-offset -1))
          (end (+ start size))
-         (multibyte enable-multibyte-characters)
          (inhibit-file-name-handlers inhibit-file-name-handlers)
          (inhibit-file-name-operation inhibit-file-name-operation))
     (save-restriction
@@ -824,11 +804,8 @@ the current tar-entry."
                       (and (eq inhibit-file-name-operation 'write-region)
                            inhibit-file-name-handlers))
                 inhibit-file-name-operation 'write-region))
-      (unwind-protect
-          (let ((coding-system-for-write 'no-conversion))
-            (set-buffer-multibyte nil)
-            (write-region start end to-file nil nil nil t))
-        (set-buffer-multibyte multibyte)))
+      (let ((coding-system-for-write 'no-conversion))
+        (write-region start end to-file nil nil nil t)))
     (message "Copied tar entry %s to %s" name to-file)))
 
 (defun tar-flag-deleted (p &optional unflag)
@@ -857,7 +834,6 @@ With a prefix argument, un-mark that many files backward."
   (tar-flag-deleted (- p) t))
 
 
-;; When this function is called, it is sure that the buffer is unibyte.
 (defun tar-expunge-internal ()
   "Expunge the tar-entry specified by the current line."
   (let* ((descriptor (tar-current-descriptor))
@@ -909,9 +885,7 @@ for this to be permanent."
   (interactive)
   (if (or noconfirm
           (y-or-n-p "Expunge files marked for deletion? "))
-      (let ((n 0)
-            (multibyte enable-multibyte-characters))
-        (set-buffer-multibyte nil)
+      (let ((n 0))
         (save-excursion
           (goto-char (point-min))
           (while (not (eobp))
@@ -922,7 +896,6 @@ for this to be permanent."
           ;; after doing the deletions, add any padding that may be necessary.
           (tar-pad-to-blocksize)
           (narrow-to-region 1 tar-header-offset))
-        (set-buffer-multibyte multibyte)
         (if (zerop n)
             (message "Nothing to expunge.")
             (message "%s files expunged.  Be sure to save this buffer." n)))))
@@ -933,7 +906,7 @@ for this to be permanent."
   (interactive)
   (save-excursion
     (goto-char (point-min))
-    (while (< (position-bytes (point)) tar-header-offset)
+    (while (< (point) tar-header-offset)
       (if (not (eq (following-char) ?\ ))
           (progn (delete-char 1) (insert " ")))
       (forward-line 1))))
@@ -1003,11 +976,13 @@ for this to be permanent."
     (list (read-string "New name: "
             (tar-header-name (tar-desc-tokens (tar-current-descriptor))))))
   (if (string= "" new-name) (error "zero length name"))
-  (if (> (length new-name) 98) (error "name too long"))
-  (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
-            new-name)
-  (tar-alter-one-field 0
-    (substring (concat new-name (make-string 99 0)) 0 99)))
+  (let ((encoded-new-name (encode-coding-string new-name
+                                                tar-file-name-coding-system)))
+    (if (> (length encoded-new-name) 98) (error "name too long"))
+    (tar-setf (tar-header-name (tar-desc-tokens (tar-current-descriptor)))
+              new-name)
+    (tar-alter-one-field 0
+     (substring (concat encoded-new-name (make-string 99 0)) 0 99))))
 
 
 (defun tar-chmod-entry (new-mode)
@@ -1024,8 +999,7 @@ for this to be permanent."
 
 (defun tar-alter-one-field (data-position new-data-string)
   (let* ((descriptor (tar-current-descriptor))
-         (tokens (tar-desc-tokens descriptor))
-         (multibyte enable-multibyte-characters))
+         (tokens (tar-desc-tokens descriptor)))
     (unwind-protect
         (save-excursion
           ;;
@@ -1035,16 +1009,21 @@ for this to be permanent."
             (forward-line 1)
             (delete-region p (point))
             (insert (tar-header-block-summarize tokens) "\n")
-            (setq tar-header-offset (position-bytes (point-max))))
+            (setq tar-header-offset (point-max)))
           
           (widen)
-          (set-buffer-multibyte nil)
           (let* ((start (+ (tar-desc-data-start descriptor) tar-header-offset -513)))
             ;;
             ;; delete the old field and insert a new one.
             (goto-char (+ start data-position))
             (delete-region (point) (+ (point) (length new-data-string))) ; <--
-            (insert new-data-string) ; <--
+
+            ;; As new-data-string is unibyte, just inserting it will
+            ;; make eight-bit chars to the corresponding multibyte
+            ;; chars.  This avoid that conversion, i.e., eight-bit
+            ;; chars are converted to multibyte form of eight-bit
+            ;; chars.
+            (insert (string-to-multibyte new-data-string))
             ;;
             ;; compute a new checksum and insert it.
             (let ((chk (tar-header-block-checksum
@@ -1062,7 +1041,6 @@ for this to be permanent."
                 chk (tar-header-name tokens))
               )))
       (narrow-to-region 1 tar-header-offset)
-      (set-buffer-multibyte multibyte)
       (tar-next-line 0))))
 
 
@@ -1086,14 +1064,9 @@ to make your changes permanent."
     (error "This buffer doesn't have an index into its superior tar file!"))
   (save-excursion
   (let ((subfile (current-buffer))
-        (subfile-multibyte enable-multibyte-characters)
         (coding buffer-file-coding-system)
         (descriptor tar-superior-descriptor)
         subfile-size)
-    ;; We must make the current buffer unibyte temporarily to avoid
-    ;; multibyte->unibyte conversion in `insert-buffer'.
-    (set-buffer-multibyte nil)
-    (setq subfile-size (buffer-size))
     (set-buffer tar-superior-buffer)
     (let* ((tokens (tar-desc-tokens descriptor))
            (start (tar-desc-data-start descriptor))
@@ -1101,28 +1074,28 @@ to make your changes permanent."
            (size (tar-header-size tokens))
            (size-pad (ash (ash (+ size 511) -9) 9))
            (head (memq descriptor tar-parse-info))
-           (following-descs (cdr head))
-           (tar-buffer-multibyte enable-multibyte-characters))
+           (following-descs (cdr head)))
       (if (not head)
         (error "Can't find this tar file entry in its parent tar file!"))
       (unwind-protect
        (save-excursion
-        (widen)
-        (set-buffer-multibyte nil)
         ;; delete the old data...
         (let* ((data-start (+ start tar-header-offset -1))
                (data-end (+ data-start (ash (ash (+ size 511) -9) 9))))
-          (delete-region data-start data-end)
+          (narrow-to-region data-start data-end)
+          (delete-region (point-min) (point-max))
           ;; insert the new data...
           (goto-char data-start)
-          (insert-buffer subfile)
-          (setq subfile-size
-                (encode-coding-region
-                 data-start (+ data-start subfile-size) coding))
+          (save-excursion
+            (set-buffer subfile)
+            (save-restriction
+              (widen)
+              (encode-coding-region 1 (point-max) coding tar-superior-buffer)))
+          (setq subfile-size (- (point-max) (point-min)))
           ;;
           ;; pad the new data out to a multiple of 512...
           (let ((subfile-size-pad (ash (ash (+ subfile-size 511) -9) 9)))
-            (goto-char (+ data-start subfile-size))
+            (goto-char (point-max))
             (insert (make-string (- subfile-size-pad subfile-size) 0))
             ;;
             ;; update the data pointer of this and all following files...
@@ -1133,6 +1106,7 @@ to make your changes permanent."
                           (+ (tar-desc-data-start desc) difference))))
             ;;
             ;; Update the size field in the header block.
+            (widen)
             (let ((header-start (- data-start 512)))
               (goto-char (+ header-start tar-size-offset))
               (delete-region (point) (+ (point) 12))
@@ -1171,21 +1145,16 @@ to make your changes permanent."
                 ;; Insert the new text after the old, before deleting,
                 ;; to preserve the window start.
                 (let ((line (tar-header-block-summarize tokens t)))
-                  (if (multibyte-string-p line)
-                      (insert-before-markers (string-as-unibyte line) "\n")
-                    (insert-before-markers line "\n")))
+                  (insert-before-markers line "\n"))
                 (delete-region p after)
                 (setq tar-header-offset (marker-position m)))
               )))
         ;; after doing the insertion, add any final padding that may be necessary.
         (tar-pad-to-blocksize))
-       (narrow-to-region 1 tar-header-offset)
-       (set-buffer-multibyte tar-buffer-multibyte)))
+       (narrow-to-region 1 tar-header-offset)))
     (set-buffer-modified-p t)   ; mark the tar file as modified
     (tar-next-line 0)
     (set-buffer subfile)
-    ;; Restore the buffer multibyteness.
-    (set-buffer-multibyte subfile-multibyte)
     (set-buffer-modified-p nil) ; mark the tar subfile as unmodified
     (message "Saved into tar-buffer `%s'.  Be sure to save that buffer!"
              (buffer-name tar-superior-buffer))
@@ -1235,14 +1204,13 @@ Leaves the region wide."
         ;; tar-header-offset turns out to be null for files fetched with W3,
         ;; at least.
         (let ((coding-system-for-write 'no-conversion))
-          (write-region (if tar-header-offset
-                            (byte-to-position tar-header-offset)
-                          (point-min))
+          (write-region (or tar-header-offset
+                            (point-min))
                         (point-max)
                         buffer-file-name nil t))
         (tar-clear-modification-flags)
         (set-buffer-modified-p nil))
-    (narrow-to-region 1 (byte-to-position tar-header-offset)))
+    (narrow-to-region 1 tar-header-offset))
   ;; Return t because we've written the file.
   t)