From 14cb7aed9a31de283eb7598956343bf2f943955a Mon Sep 17 00:00:00 2001
From: Vince Darley <vincentdarley@sourceforge.net>
Date: Tue, 29 Jun 2004 12:47:00 +0000
Subject: [PATCH] fix to zipvfs

---
 ChangeLog          |  5 +++++
 library/zipvfs.tcl | 19 ++++++++++---------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e3e31aa..caa981e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2004-06-29  Vince Darley <vincentdarley@sourceforge.net>
+
+	* library/zipvfs.tcl: fix to bug finding zip header (reported on
+	Tcl'ers wiki).
+
 2004-06-09  Jeff Hobbs  <jeffh@ActiveState.com>
 
 	* Makefile.in: corrected targets that use 'for' over what may be
diff --git a/library/zipvfs.tcl b/library/zipvfs.tcl
index 253c442..13a98d3 100644
--- a/library/zipvfs.tcl
+++ b/library/zipvfs.tcl
@@ -328,19 +328,20 @@ proc zip::Data {fd arr {varPtr ""} {verify 0}} {
 proc zip::EndOfArchive {fd arr} {
     upvar 1 $arr cb
 
-    seek $fd -22 end
-    set pos [tell $fd]
-    set hdr [read $fd 22]
+    seek $fd -512 end
+    set hdr [read $fd 512]
+    set pos [string first "PK\05\06" $hdr]
+    if {$pos == -1} {
+	error "no header found"
+    }
+    set hdr [string range $hdr [expr $pos + 4] [expr $pos + 21]]
+    set pos [expr [tell $fd] + $pos - 512]
 
-    binary scan $hdr A4ssssiis xhdr \
+    binary scan $hdr ssssiis \
 	cb(ndisk) cb(cdisk) \
 	cb(nitems) cb(ntotal) \
 	cb(csize) cb(coff) \
-	cb(comment) 
-
-    if { ![string equal "PK\05\06" $xhdr]} {
-	error "bad header"
-    }
+	cb(comment)
 
     set cb(ndisk)	[u_short $cb(ndisk)]
     set cb(nitems)	[u_short $cb(nitems)]
-- 
2.23.0