How to deal with Curl collection garbled characters and collection of PHP failures

The PHPPHP program uses gbk2312 encoding to collect garbled code from Curl and cannot collect the code: & lt ;? Php $ url & quot; www.sina.com.cn & quot; gbk2312 encoding $ url & quot; www.163.com & quot; gbk2312 encoding $ url & quot; www. sohu Curl collection garbled code and collection of PHP
PHP programs are encoded with gbk2312:

$ Url = "http://www.sina.com.cn"; // gbk2312 encoding
// $ Url = "http://www.163.com"; // gbk2312 encoding
// $ Url = "http://www.sohu.com"; // gbk2312 encoding


$ Ch = curl_init ($ url );
Curl_setopt ($ ch, CURLOPT_RETURNTRANSFER, true); // return the obtained output text stream
$ Ret = curl_exec ($ ch );
Curl_setopt ($ ch, CURLOPT_TIMEOUT, 1 );
Curl_close ($ ch );
Echo $ ret;

?>

It is normal when sina.com.cn is collected, but it is null when 163.com is collected, and the code is lost when sohu.com is collected.
What's going on? How can this problem be solved? Why? Thank you !!! I'm sorry.

------ Solution --------------------
I just came to get the score.

PHP code

$curl=curl_init('http://www.163.com');curl_setopt($curl,CURLOPT_RETURNTRANSFER,1);curl_setopt($curl,CURLOPT_USERAGENT,'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322)');$html=curl_exec($curl);var_dump($html);$curl=curl_init('http://www.sohu.com');curl_setopt($curl,CURLOPT_RETURNTRANSFER,1);curl_setopt($curl,CURLOPT_USERAGENT,'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322)');$html=curl_exec($curl);//$html=strstr($html,'<');$html=gzdecode($html);var_dump($html);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;   }