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Support ZIP files that use Zip64 extensions

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* lisp/arc-mode.el (archive-zip-summarize): Handle the new ZIP
format of central directory offsets used by Zip64 extensions.
(Bug#20665)
This commit is contained in:
Eli Zaretskii 2015-05-27 17:35:11 +03:00
parent abf082383a
commit 171981622f
1 changed files with 29 additions and 2 deletions
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31
lisp/arc-mode.el
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@ -1811,11 +1811,38 @@ This doesn't recover lost files, it just undoes changes in the buffer itself."
(defun archive-zip-summarize ()
(goto-char (- (point-max) (- 22 18)))
(search-backward-regexp "[P]K\005\006")
(let ((p (+ (point-min) (archive-l-e (+ (point) 16) 4)))
(let ((p (archive-l-e (+ (point) 16) 4))
(maxlen 8)
(totalsize 0)
files
visual)
visual
emacs-int-has-32bits)
(when (= p -1)
;; If the offset of end-of-central-directory is -1, this is a
;; Zip64 extended ZIP file format, and we need to glean the info
;; from Zip64 records instead.
;;
;; First, find the Zip64 end-of-central-directory locator.
(search-backward "PK\006\007")
;; Pay attention: the offset of Zip64 end-of-central-directory
;; is a 64-bit field, so it could overflow the Emacs integer
;; even on a 64-bit host, let alone 32-bit one. But since we've
;; already read the zip file into a buffer, and this is a byte
;; offset into the file we've read, it must be short enough, so
;; such an overflow can never happen, and we can safely read
;; these 8 bytes into an Emacs integer. Moreover, on host with
;; 32-bit Emacs integer we can only read 4 bytes, since they are
;; stored in little-endian byte order.
(setq emacs-int-has-32bits (<= most-positive-fixnum #x1fffffff))
(setq p (+ (point-min)
(archive-l-e (+ (point) 8) (if emacs-int-has-32bits 4 8))))
(goto-char p)
;; We should be at Zip64 end-of-central-directory record now.
(or (string= "PK\006\006" (buffer-substring p (+ p 4)))
(error "Unrecognized ZIP file format"))
;; Offset to central directory:
(setq p (+ (point-min)
(archive-l-e (+ p 48) (if emacs-int-has-32bits 4 8)))))
(while (string= "PK\001\002" (buffer-substring p (+ p 4)))
(let* ((creator (byte-after (+ p 5)))
;; (method (archive-l-e (+ p 10) 2))