Gzdecode::parse(): bool

203    public function parse()204    {205        if ($this->compressed_size >= $this->min_compressed_size) {206            $len = 0;207 208            // Check ID1, ID2, and CM209            if (substr($this->compressed_data, 0, 3) !== "\x1F\x8B\x08") {210                return false;211            }212 213            // Get the FLG (FLaGs)214            $this->flags = ord($this->compressed_data[3]);215 216            // FLG bits above (1 << 4) are reserved217            if ($this->flags > 0x1F) {218                return false;219            }220 221            // Advance the pointer after the above222            $this->position += 4;223 224            // MTIME225            $mtime = substr($this->compressed_data, $this->position, 4);226            // Reverse the string if we're on a big-endian arch because l is the only signed long and is machine endianness227            if (current(unpack('S', "\x00\x01")) === 1) {228                $mtime = strrev($mtime);229            }230            $this->MTIME = current(unpack('l', $mtime));231            $this->position += 4;232 233            // Get the XFL (eXtra FLags)234            $this->XFL = ord($this->compressed_data[$this->position++]);235 236            // Get the OS (Operating System)237            $this->OS = ord($this->compressed_data[$this->position++]);238 239            // Parse the FEXTRA240            if ($this->flags & 4) {241                // Read subfield IDs242                $this->SI1 = $this->compressed_data[$this->position++];243                $this->SI2 = $this->compressed_data[$this->position++];244 245                // SI2 set to zero is reserved for future use246                if ($this->SI2 === "\x00") {247                    return false;248                }249 250                // Get the length of the extra field251                $len = current(unpack('v', substr($this->compressed_data, $this->position, 2)));252                $this->position += 2;253 254                // Check the length of the string is still valid255                $this->min_compressed_size += $len + 4;256                if ($this->compressed_size >= $this->min_compressed_size) {257                    // Set the extra field to the given data258                    $this->extra_field = substr($this->compressed_data, $this->position, $len);259                    $this->position += $len;260                } else {261                    return false;262                }263            }264 265            // Parse the FNAME266            if ($this->flags & 8) {267                // Get the length of the filename268                $len = strcspn($this->compressed_data, "\x00", $this->position);269 270                // Check the length of the string is still valid271                $this->min_compressed_size += $len + 1;272                if ($this->compressed_size >= $this->min_compressed_size) {273                    // Set the original filename to the given string274                    $this->filename = substr($this->compressed_data, $this->position, $len);275                    $this->position += $len + 1;276                } else {277                    return false;278                }279            }280 281            // Parse the FCOMMENT282            if ($this->flags & 16) {