From f2c624a23640eb1e47d83842d0bf8303209155b6 Mon Sep 17 00:00:00 2001
From: Andrew Dolgov <fox@madoka.volgo-balt.ru>
Date: Tue, 2 Apr 2013 00:04:05 +0400
Subject: [PATCH] add php native gzdecode()
---
include/functions.php | 114 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 113 insertions(+), 1 deletion(-)
diff --git a/include/functions.php b/include/functions.php
index 75ca6daf9..a559ed1da 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -3934,9 +3934,121 @@
}
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;
}
}
--
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