Re: [Phpwiki-talk] ZIP upload doesn't work

[Bob A. <apt...@cy...>]

Hi,

Reini Urban wrote:
[...]
> Can you send me your ZIP please to rei...@gm...
> 
> I fixed a problem with loadfile and archived version to recreate the old 
> versions recently in CVS. But a CRC32 problem would be interesting.

I ran into the same trouble tonight importing a zip dump from 1.3.10
into a fresh installation of 1.3.12p3 - I have some diagnostic info and
a workaround. Hint: the problem is with the CRC32 checksum comparison,
not the zip files.

First, in order to get better diagnostics, I changed lib/ziplib.php to:

   186  function zip_inflate ($data, $crc32, $uncomp_size)
   187  {
   188      if (function_exists('gzinflate')) {
   189          $data = gzinflate($data);
   190          if (strlen($data) != $uncomp_size)
   191              trigger_error("not enough output from gzinflate",
E_USER_ERROR);
   192          # if (zip_crc32($data) != $crc32)
   193          $zcrc32 = zip_crc32($data);
   194          if ($zcrc32 != $crc32)
   195              trigger_error("CRC32 mismatch: calculated=$zcrc32,
expected=$crc32 ", E_USER_ERROR);
   196          return $data;
   197      }

My zip file upload fails with:

lib/ziplib.php:195: Error: CRC32 mismatch: calculated=-337476845,
expected=3957490451

Note that 2^32 = 4294967296 and 4294967296 - 337476845 = 3957490451

My guess is there's some problem with signed vs unsigned 32-bit
integers, pack/unpack, or something along those lines - once I changed
lib/ziplib.php to

   186  function zip_inflate ($data, $crc32, $uncomp_size)
   187  {
   188      if (function_exists('gzinflate')) {
   189          $data = gzinflate($data);
   190          if (strlen($data) != $uncomp_size)
   191              trigger_error("not enough output from gzinflate",
E_USER_ERROR);
   192          # if (zip_crc32($data) != $crc32)
   193          $zcrc32 = zip_crc32($data);
   194
   195          if ($zcrc32 < 0) {
   196              $zcrc32 += 4294967296;
   197          }
   198
   199          if ($zcrc32 != $crc32)
   200              trigger_error("CRC32 mismatch: calculated=$zcrc32,
expected=$crc32 ", E_USER_ERROR);
   201          return $data;
   202      }

the zip file uploaded and imported just fine. Well, it stopped importing
anything past the first version of a page (not what I wanted) but I've
been fighting with that particular problem for *years* with phpwiki. I
worked around the CRC issue at least.

hth,

-- Bob