php实现gb2312和unicode间编码转换(3)_PHP教程

<?
function gb2utf8($gb){
if(!trim($gb)) return $gb;
$filename="gb2312.txt";
$tmp=file($filename);
$codetable=array();
while(list($key,$value)=each($tmp))
$codetable[hexdec(substr($value,0,6))]=substr($value,7,6);

$utf8="";
while($gb) {
if (ord(substr($gb,0,1))>127) {
$this=substr($gb,0,2);
$gb=substr($gb,2,strlen($gb)-2);
$utf8.=u2utf8(hexdec($codetable[hexdec(bin2hex($this))-0x8080]));
}else{
$this=substr($gb,0,1);
$gb=substr($gb,1,strlen($gb)-1);
$utf8.=u2utf8($this);
}
}
return $utf8;
}

function u2utf8($c){
$str="";
if ($c < 0x80) {
$str.=$c;
} else if ($c < 0x800) {
$str.=chr(0xC0 | $c>>6);
$str.=chr(0x80 | $c & 0x3F);
} else if ($c < 0x10000) {
$str.=chr(0xE0 | $c>>12);
$str.=chr(0x80 | $c>>6 & 0x3F);
$str.=chr(0x80 | $c & 0x3F);
} else if ($c < 0x200000) {
$str.=chr(0xF0 | $c>>18);
$str.=chr(0x80 | $c>>12 & 0x3F);
$str.=chr(0x80 | $c>>6 & 0x3F);
$str.=chr(0x80 | $c & 0x3F);
}
return $str;
}

?>