}
if (!function_exists('gzdecode')) {
- /* function gzdecode($string) { // no support for 2nd argument
+ function gzdecode($string) { // no support for 2nd argument
return file_get_contents('compress.zlib://data:who/cares;base64,'.
base64_encode($string));
- } */
-
-
- function gzdecode($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;
}
}