Merge pull request #15 from serlin74/master

Fix reading of archives with files > 8GB.

Archive/Tar.php

@@ -1697,7 +1697,7 @@ public function _readHeader($v_binary_data, &$v_header)
         $v_header['mode'] = OctDec(trim($v_data['mode']));
         $v_header['uid'] = OctDec(trim($v_data['uid']));
         $v_header['gid'] = OctDec(trim($v_data['gid']));
-        $v_header['size'] = OctDec(trim($v_data['size']));
+        $v_header['size'] = $this->_tarRecToSize($v_data['size']);
         $v_header['mtime'] = OctDec(trim($v_data['mtime']));
         if (($v_header['typeflag'] = $v_data['typeflag']) == "5") {
             $v_header['size'] = 0;
@@ -1716,6 +1716,40 @@ public function _readHeader($v_binary_data, &$v_header)
         return true;
     }
 
+    /**
+     * Convert Tar record size to actual size
+     *
+     * @param string $tar_size
+     * @return size of tar record in bytes
+     */
+    private function _tarRecToSize($tar_size)
+    {
+        /*
+         * First byte of size has a special meaning if bit 7 is set.
+         *
+         * Bit 7 indicates base-256 encoding if set.
+         * Bit 6 is the sign bit.
+         * Bits 5:0 are most significant value bits.
+         */
+        $ch = ord($tar_size[0]);
+        if ($ch & 0x80) {
+            // Full 12-bytes record is required.
+            $rec_str = $tar_size . "\x00";
+
+            $size = ($ch & 0x40) ? -1 : 0;
+            $size = ($size << 6) | ($ch & 0x3f);
+
+            for ($num_ch = 1; $num_ch < 12; ++$num_ch) {
+                $size = ($size * 256) + ord($rec_str[$num_ch]);
+            }
+
+            return $size;
+
+        } else {
+            return OctDec(trim($tar_size));
+        }
+    }
+
     /**
      * Detect and report a malicious file name
      *