note 82930 added to function.gzdecode
| From: | katzlbtjunk at hotmail dot com | Date: | Fri, 02 May 2008 14:15:45 +0000 |
| Subject: | note 82930 added to function.gzdecode | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-138995@lists.php.net to get a copy of this message | ||
3 more bugs found and fixed:
1. failed to work when the gz contained a filename - FIXED
2. failed to work on 64-bit architecture (checksum) - FIXED
3. failed to work when the gz contained a comment - cannot verify.
Returns some errors (not all!) and filename.
<?php function
gzdecode($data,&$filename='',&$error='',$maxlength=null)
{
$len = strlen($data);
if ($len < 18 || strcmp(substr($data,0,2),"\x1f\x8b")) {
$error = "Not in GZIP format.";
return null; // Not GZIP format (See RFC 1952)
}
$method = ord(substr($data,2,1)); // Compression method
$flags = ord(substr($data,3,1)); // Flags
if ($flags & 31 != $flags) {
$error = "Reserved bits not allowed.";
return null;
}
// NOTE: $mtime may be negative (PHP integer limitations)
$mtime = unpack("V", substr($data,4,4));
$mtime = $mtime[1];
$xfl = substr($data,8,1);
$os = substr($data,8,1);
$headerlen = 10;
$extralen = 0;
$extra = "";
if ($flags & 4) {
// 2-byte length prefixed EXTRA data in header
if ($len - $headerlen - 2 < 8) {
return false; // invalid
}
$extralen = unpack("v",substr($data,8,2));
$extralen = $extralen[1];
if ($len - $headerlen - 2 - $extralen < 8) {
return false; // invalid
}
$extra = substr($data,10,$extralen);
$headerlen += 2 + $extralen;
}
$filenamelen = 0;
$filename = "";
if ($flags & 8) {
// C-style string
if ($len - $headerlen - 1 < 8) {
return false; // invalid
}
$filenamelen = strpos(substr($data,$headerlen),chr(0));
if ($filenamelen === false || $len - $headerlen - $filenamelen - 1 < 8) {
return false; // invalid
}
$filename = substr($data,$headerlen,$filenamelen);
$headerlen += $filenamelen + 1;
}
$commentlen = 0;
$comment = "";
if ($flags & 16) {
// C-style string COMMENT data in header
if ($len - $headerlen - 1 < 8) {
return false; // invalid
}
$commentlen = strpos(substr($data,$headerlen),chr(0));
if ($commentlen === false || $len - $headerlen - $commentlen - 1 < 8) {
return false; // Invalid header format
}
$comment = substr($data,$headerlen,$commentlen);
$headerlen += $commentlen + 1;
}
$headercrc = "";
if ($flags & 2) {
// 2-bytes (lowest order) of CRC32 on header present
if ($len - $headerlen - 2 < 8) {
return false; // invalid
}
$calccrc = crc32(substr($data,0,$headerlen)) & 0xffff;
$headercrc = unpack("v", substr($data,$headerlen,2));
$headercrc = $headercrc[1];
if ($headercrc != $calccrc) {
$error = "Header checksum failed.";
return false; // Bad header CRC
}
$headerlen += 2;
}
// GZIP FOOTER
$datacrc = unpack("V",substr($data,-8,4));
$datacrc = sprintf('%u',$datacrc[1] & 0xFFFFFFFF);
$isize = unpack("V",substr($data,-4));
$isize = $isize[1];
// decompression:
$bodylen = $len-$headerlen-8;
if ($bodylen < 1) {
// IMPLEMENTATION BUG!
return null;
}
$body = substr($data,$headerlen,$bodylen);
$data = "";
if ($bodylen > 0) {
switch ($method) {
case 8:
// Currently the only supported compression method:
$data = gzinflate($body,$maxlength);
break;
default:
$error = "Unknown compression method.";
return false;
}
} // zero-byte body content is allowed
// Verifiy CRC32
$crc = sprintf("%u",crc32($data));
$crcOK = $crc == $datacrc;
$lenOK = $isize == strlen($data);
if (!$lenOK || !$crcOK) {
$error = ( $lenOK ? '' : 'Length check FAILED. ') . ( $crcOK ?
'' : 'Checksum FAILED.');
return false;
}
return $data;
}
?>
----
Server IP: 192.35.244.50
Probable Submitter: 194.166.195.75
----
Manual Page -- http://www.php.net/manual/en/function.gzdecode.php
Edit -- https://master.php.net/note/edit/82930
Del: integrated -- https://master.php.net/note/delete/82930/integrated
Del: useless -- https://master.php.net/note/delete/82930/useless
Del: bad code -- https://master.php.net/note/delete/82930/bad+code
Del: spam -- https://master.php.net/note/delete/82930/spam
Del: non-english -- https://master.php.net/note/delete/82930/non-english
Del: in docs -- https://master.php.net/note/delete/82930/in+docs
Del: other reasons-- https://master.php.net/note/delete/82930
Reject -- https://master.php.net/note/reject/82930
Search -- https://master.php.net/manage/user-notes.php