$flg = ord(substr($gz_data, 3, 1));

[1000] Fix | Delete

if ($flg > 0) {

[1001] Fix | Delete

if ($flg & 4) {

[1002] Fix | Delete

list($xlen) = unpack('v', substr($gz_data, $i, 2));

[1003] Fix | Delete

$i += 2 + $xlen;

[1004] Fix | Delete

}

[1005] Fix | Delete

[1006] Fix | Delete

if ($flg & 8) {

[1007] Fix | Delete

$i = strpos($gz_data, "\0", $i) + 1;

[1008] Fix | Delete

}

[1009] Fix | Delete

[1010] Fix | Delete

if ($flg & 16) {

[1011] Fix | Delete

$i = strpos($gz_data, "\0", $i) + 1;

[1012] Fix | Delete

}

[1013] Fix | Delete

[1014] Fix | Delete

if ($flg & 2) {

[1015] Fix | Delete

$i += 2;

[1016] Fix | Delete

}

[1017] Fix | Delete

}

[1018] Fix | Delete

[1019] Fix | Delete

$decompressed = self::compatible_gzinflate(substr($gz_data, $i));

[1020] Fix | Delete

if ($decompressed !== false) {

[1021] Fix | Delete

return $decompressed;

[1022] Fix | Delete

}

[1023] Fix | Delete

}

[1024] Fix | Delete

[1025] Fix | Delete

// If the data is Huffman Encoded, we must first strip the leading 2

[1026] Fix | Delete

// byte Huffman marker for gzinflate()

[1027] Fix | Delete

// The response is Huffman coded by many compressors such as

[1028] Fix | Delete

// java.util.zip.Deflater, Ruby's Zlib::Deflate, and .NET's

[1029] Fix | Delete

// System.IO.Compression.DeflateStream.

[1030] Fix | Delete

//

[1031] Fix | Delete

// See https://decompres.blogspot.com/ for a quick explanation of this

[1032] Fix | Delete

// data type

[1033] Fix | Delete

$huffman_encoded = false;

[1034] Fix | Delete

[1035] Fix | Delete

// low nibble of first byte should be 0x08

[1036] Fix | Delete

list(, $first_nibble) = unpack('h', $gz_data);

[1037] Fix | Delete

[1038] Fix | Delete

// First 2 bytes should be divisible by 0x1F

[1039] Fix | Delete

list(, $first_two_bytes) = unpack('n', $gz_data);

[1040] Fix | Delete

[1041] Fix | Delete

if ($first_nibble === 0x08 && ($first_two_bytes % 0x1F) === 0) {

[1042] Fix | Delete

$huffman_encoded = true;

[1043] Fix | Delete

}

[1044] Fix | Delete

[1045] Fix | Delete

if ($huffman_encoded) {

[1046] Fix | Delete

$decompressed = @gzinflate(substr($gz_data, 2));

[1047] Fix | Delete

if ($decompressed !== false) {

[1048] Fix | Delete

return $decompressed;

[1049] Fix | Delete

}

[1050] Fix | Delete

}

[1051] Fix | Delete

[1052] Fix | Delete

if (substr($gz_data, 0, 4) === "\x50\x4b\x03\x04") {

[1053] Fix | Delete

// ZIP file format header

[1054] Fix | Delete

// Offset 6: 2 bytes, General-purpose field

[1055] Fix | Delete

// Offset 26: 2 bytes, filename length

[1056] Fix | Delete

// Offset 28: 2 bytes, optional field length

[1057] Fix | Delete

// Offset 30: Filename field, followed by optional field, followed

[1058] Fix | Delete

// immediately by data

[1059] Fix | Delete

list(, $general_purpose_flag) = unpack('v', substr($gz_data, 6, 2));

[1060] Fix | Delete

[1061] Fix | Delete

// If the file has been compressed on the fly, 0x08 bit is set of

[1062] Fix | Delete

// the general purpose field. We can use this to differentiate

[1063] Fix | Delete

// between a compressed document, and a ZIP file

[1064] Fix | Delete

$zip_compressed_on_the_fly = ((0x08 & $general_purpose_flag) === 0x08);

[1065] Fix | Delete

[1066] Fix | Delete

if (!$zip_compressed_on_the_fly) {

[1067] Fix | Delete

// Don't attempt to decode a compressed zip file

[1068] Fix | Delete

return $gz_data;

[1069] Fix | Delete

}

[1070] Fix | Delete

[1071] Fix | Delete

// Determine the first byte of data, based on the above ZIP header

[1072] Fix | Delete

// offsets:

[1073] Fix | Delete

$first_file_start = array_sum(unpack('v2', substr($gz_data, 26, 4)));

[1074] Fix | Delete

$decompressed = @gzinflate(substr($gz_data, 30 + $first_file_start));

[1075] Fix | Delete

if ($decompressed !== false) {

[1076] Fix | Delete

return $decompressed;

[1077] Fix | Delete

}

[1078] Fix | Delete

[1079] Fix | Delete

return false;

[1080] Fix | Delete

}

[1081] Fix | Delete

[1082] Fix | Delete

// Finally fall back to straight gzinflate

[1083] Fix | Delete

$decompressed = @gzinflate($gz_data);

[1084] Fix | Delete

if ($decompressed !== false) {

[1085] Fix | Delete

return $decompressed;

[1086] Fix | Delete

}

[1087] Fix | Delete

[1088] Fix | Delete

// Fallback for all above failing, not expected, but included for

[1089] Fix | Delete

// debugging and preventing regressions and to track stats

[1090] Fix | Delete

$decompressed = @gzinflate(substr($gz_data, 2));

[1091] Fix | Delete

if ($decompressed !== false) {

[1092] Fix | Delete

return $decompressed;

[1093] Fix | Delete

}

[1094] Fix | Delete

[1095] Fix | Delete

return false;

[1096] Fix | Delete

}

[1097] Fix | Delete

}

[1098] Fix | Delete

[1099] Fix | Delete