From a0f2a3e105074380f0f02882ab075ec48049f63a Mon Sep 17 00:00:00 2001
From: Andrew Dolgov <fox@madoka.volgo-balt.ru>
Date: Tue, 19 Mar 2013 09:33:04 +0400
Subject: [PATCH] enable automatic decoding of gzipped data when CURL is not
 available

---
 include/functions.php | 122 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)

diff --git a/include/functions.php b/include/functions.php
index a7ac07b53..ad87c90c2 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -352,6 +352,9 @@
 
 			$data = @file_get_contents($url);
 
+			$gzdecoded = gzdecode($data);
+			if ($gzdecoded) $data = $gzdecoded;
+
 			if (!$data && function_exists('error_get_last')) {
 				$error = error_get_last();
 				$fetch_last_error = $error["message"];
@@ -3997,4 +4000,123 @@
 		return $rv;
 	}
 
+	// http://php.net/gzencode
+	function gzdecode($data) {
+		$len = strlen($data);
+		if ($len < 18 || strcmp(substr($data,0,2),"\x1f\x8b")) {
+			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) {
+			// Reserved bits are set -- NOT ALLOWED by RFC 1952
+			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 format
+			}
+			$extralen = unpack("v",substr($data,8,2));
+			$extralen = $extralen[1];
+			if ($len - $headerlen - 2 - $extralen < 8) {
+				return false;		// Invalid format
+			}
+			$extra = substr($data,10,$extralen);
+			$headerlen += 2 + $extralen;
+		}
+
+		$filenamelen = 0;
+		$filename = "";
+		if ($flags & 8) {
+			// C-style string file NAME data in header
+			if ($len - $headerlen - 1 < 8) {
+				return false;		// Invalid format
+			}
+			$filenamelen = strpos(substr($data,8+$extralen),chr(0));
+			if ($filenamelen === false || $len - $headerlen - $filenamelen - 1 < 8) {
+				return false;		// Invalid format
+			}
+			$filename = substr($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 format
+			}
+			$commentlen = strpos(substr($data,8+$extralen+$filenamelen),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 & 1) {
+			// 2-bytes (lowest order) of CRC32 on header present
+			if ($len - $headerlen - 2 < 8) {
+				return false;		// Invalid format
+			}
+			$calccrc = crc32(substr($data,0,$headerlen)) & 0xffff;
+			$headercrc = unpack("v", substr($data,$headerlen,2));
+			$headercrc = $headercrc[1];
+			if ($headercrc != $calccrc) {
+				return false;		// Bad header CRC
+			}
+			$headerlen += 2;
+		}
+
+		// GZIP FOOTER - These be negative due to PHP's limitations
+		$datacrc = unpack("V",substr($data,-8,4));
+		$datacrc = $datacrc[1];
+		$isize = unpack("V",substr($data,-4));
+		$isize = $isize[1];
+
+		// Perform the decompression:
+		$bodylen = $len-$headerlen-8;
+		if ($bodylen < 1) {
+			// This should never happen - 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);
+					break;
+				default:
+					// Unknown compression method
+					return false;
+			}
+		} else {
+			// I'm not sure if zero-byte body content is allowed.
+			// Allow it for now...	Do nothing...
+		}
+
+		// Verifiy decompressed size and CRC32:
+		// NOTE: This may fail with large data sizes depending on how
+		//			 PHP's integer limitations affect strlen() since $isize
+		//			 may be negative for large sizes.
+		if ($isize != strlen($data) || crc32($data) != $datacrc) {
+			// Bad format!	Length or CRC doesn't match!
+			return false;
+		}
+		return $data;
+	}
+
 ?>