用PHP实现将GB编码转换为UTF8

2015-01-24信息快讯网
gb2utf8.php 文件如下:
<?php 
Class GB2UTF8  
{  
var $gb; // 待转换的GB2312字符串  
var $utf8; // 转换后的UTF8字符串  
var $CodeTable; // 转换过程中使用的GB2312代码文件数组  
var $ErrorMsg; // 转换过程之中的错误讯息  

function GB2UTF8($InStr="")  
{  
$this->gb=$InStr;  
$this->SetGb2312();  
($this->gb=="")?0:$this->Convert();  
}  

function SetGb2312($InStr="gb2312.txt")  
{ // 设置gb2312代码文件,默认为gb2312.txt  
$this->ErrorMsg="";  
$tmp=@file($InStr);  
 if (!$tmp) {  
 $this->ErrorMsg="No GB2312";  
 return false;  
 }  
$this->CodeTable=array();  
while(list($key,$value)=each($tmp)) {  
$this->CodeTable[hexdec(substr($value,0,6))]=substr($value,7,6);  
}  
}  

function Convert()  
{ // 转换GB2312字符串到UTF8字符串,需预先设置$gb  
$this->utf8="";  
if(!trim($this->gb) || $this->ErrorMsg!="") {  
return ($this->utf8=$this->ErrorMsg);  
}  
 $str=$this->gb;  

while($str) {  
if (ord(substr($str,0,1))>127)  
{  
$tmp=substr($str,0,2);  
$str=substr($str,2,strlen($str));  
$tmp=$this->U2UTF8(hexdec($this->CodeTable[hexdec(bin2hex($tmp))-0x8080]));  
for($i=0;$i<strlen ($tmp);$i+=3)  
$this->utf8.=chr(substr($tmp,$i,3));  
}  
else  
{  
$tmp=substr($str,0,1);  
$str=substr($str,1,strlen($str));  
$this->utf8.=$tmp;  
}  
}  
return $this->utf8;  
}  

function U2UTF8($InStr)  
{  
for($i=0;$i<count($InStr);$i++)  
$str="";  
if ($InStr < 0x80) {  
$str.=ord($InStr);  
}  
else if ($InStr < 0x800) {  
$str.=(0xC0 | $InStr>>6);  
$str.=(0x80 | $InStr & 0x3F);  
}  
else if ($InStr < 0x10000) {  
$str.=(0xE0 | $InStr>>12);  
$str.=(0x80 | $InStr>>6 & 0x3F);  
$str.=(0x80 | $InStr & 0x3F);  
}  
else if ($InStr < 0x200000) {  
$str.=(0xF0 | $InStr>>18);  
$str.=(0x80 | $InStr>>12 & 0x3F);  
$str.=(0x80 | $InStr>>6 & 0x3F);  
$str.=(0x80 | $InStr & 0x3F);  
}  
return $str;  
}  
} 
?>

测试文件如下:
<?php 
Header("Content-type: image/png");  
$im = imagecreate(400,300);  
$black = ImageColorAllocate($im, 0,0,0);  
$white = ImageColorAllocate($im, 184,44,6);  
include("gb2utf8.php");  
$obj=new gb2utf8();  
$obj->gb="123abc中国456def测试正确";  
$obj->Convert();  
ImageTTFText($im, 20, 0, 5, 50, $white, "SIMKAI.TTF", $obj->utf8);  
ImagePNG($im);  
ImageDestroy($im); 
?> 


说明: 
需要正确设置font文件,请先确认可以使用font直接(不使用gb2utf8)输出英文。 
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