Improve locating the central zip directory

diff --git a/wcfsetup/install/files/lib/system/io/Zip.class.php b/wcfsetup/install/files/lib/system/io/Zip.class.php
index 9332d5dae0d9f4683751c3c9ed1adbf23cce96df..d0fb3c4beab0e663b5fc9878e92f376719650213 100644 (file)
--- a/wcfsetup/install/files/lib/system/io/Zip.class.php
+++ b/wcfsetup/install/files/lib/system/io/Zip.class.php
@@ -132,14 +132,28 @@ class Zip extends File implements IArchive {
         * Moves the file-pointer to the beginning of the Central Directory.
         */
        public function jumpToCentralDirectory() {
-               $this->seek(0);
-               while ($this->isFile()) {
-                       $this->skipFile();
-                       $offset = $this->tell();
-               }
+               $this->seek(0, SEEK_END);
+               $lastOffset = $this->tell();
+               $this->seek(-4, SEEK_CUR);
+               
+               do {
+                       if ($this->read(4) === self::EOF_SIGNATURE) {
+                               $eof = unpack('vdiskNo/vdiskWithCentralDirectory/vdiskEntries/vtotalEntries/VcentralDirectorySize/VcentralDirectoryOffset/vcommentLength', $this->read(18));
+                               if ($eof['commentLength'] + $this->tell() === $lastOffset) {
+                                       $this->seek($eof['centralDirectoryOffset']);
+                                       break;
+                               }
+                               else {
+                                       // some part of the comment looked like the EOF_SIGNATURE
+                                       $this->seek(-18, SEEK_CUR);
+                               }
+                       }
+                       
+                       $this->seek(-5, SEEK_CUR);
+               } while(true);
                
                if ($this->read(4) !== self::CENTRAL_DIRECTORY_SIGNATURE) throw new SystemException('Unable to locate central directory');
-               $this->seek($offset);
+               $this->seek(-4, SEEK_CUR);
        }
        
        /**
@@ -191,10 +205,10 @@ class Zip extends File implements IArchive {
                
                if ($this->read(4) !== self::EOF_SIGNATURE) throw new SystemException('Could not find the end of Central Directory');
                
-               $eof = unpack('vdiskNo/vdiskWithCentralDirectory/vdiskEntries/vtotalEntries/vcentralDirectorySize', $this->read(12));
+               $eof = unpack('vdiskNo/vdiskWithCentralDirectory/vdiskEntries/vtotalEntries/VcentralDirectorySize', $this->read(12));
                // check size of Central Directory
                if ($size !== $eof['centralDirectorySize']) throw new SystemException('Central Directory size does not match');
-               $eof += unpack('vcentralDirectoryOffset/vcommentLength', $this->read(6));
+               $eof += unpack('VcentralDirectoryOffset/vcommentLength', $this->read(6));
                
                // read comment
                if ($eof['commentLength'] > 0) $eof['comment'] = $this->read($eof['commentLength']);