一个绘图的程序，我在本机的php4上运行没问题，在网上虚拟主机的PHP5.1.1里就不行，网上的又不显示错误信息的，头大。最后检查下来是这段自定义函数，这是绘图里加中文的编码函数，在网上找的，请大家帮忙看看是哪里PHP5会不支持，感激不尽
[PHP]
<?php
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);

$ret="";
$utf8="";
while($gb)
{
if (ord(substr($gb,0,1))>127)
{
$this=substr($gb,0,2);
$gb=substr($gb,2,strlen($gb));
$utf8=u2utf8(hexdec($codetable[hexdec(bin2hex($this))-0x8080]));
for($i=0;$i $ret.=chr(substr($utf8,$i,3));
}
else
{
$ret.=substr($gb,0,1);
$gb=substr($gb,1,strlen($gb));
}
}
return $ret;
}


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

echo 'test';
?>
[/PHP]