PHP does not use the iconv library to perform gb2312 and utf-8 encoding conversion functions

//Usage of comparison table
$filename = "gb2utf8.txt";
$fp = fopen($filename,"r");
while(! feof ($fp)) {
list($gb,$utf8) = fgetcsv($fp,10);
$charset[$gb] = $utf8;
}
fclose($fp);
//The above reading Lookup table to array for later use
/**gb2312 to utf-8**/
function gb2utf8($text, &$charset) {
//Extract the components in the text, Chinese characters are one element, continuous The non-Chinese characters are an element
preg_match_all("/(?:[x80-xff].)|[x01-x7f]+/",$text,$tmp);
$tmp = $tmp[0];
/ /Separate Chinese characters
$ar = array_intersect($tmp, array_keys($charset));
//Replace Chinese character encoding
foreach($ar as $k=>$v)
$tmp[$k] = $charset [$v];
//Return the escaped string
return join('',$tmp);
}
/**utf-8 to gb2312**/
function utf82gb($ text, &$charset) {
$p = "/[xf0-xf7][x80-xbf]{3}|[xe0-xef][x80-xbf]{2}|[xc2-xdf][x80-xbf ]|[x01-x7f]+/";
preg_match_all($p,$text,$r);
$utf8 = array_flip($charset);
foreach($r[0] as $k=>$v )
if(isset($utf8[$v]))
$r[0][$k] = $utf8[$v];
return join('',$r[0]);
}< /p>
//Test
$s = gb2utf8('This is a test of the comparison table', $charset);
echo utf82gb($s, $charset);
?>