用php实现gb2312和unicode(UTF-8)间的编码转换

下面的例子是将 gb2312 转换为 uft-8 这种形式
php4.3.1以后的iconv函数很好用的，只是需要自己写一个uft8到unicode的转换函数
查表(gb2312.txt)也行

$text = "电子书库";
preg_match_all("/[\x80-\xff]?./",$text,$ar);
foreach($ar[0] as $v)
  echo "".utf8_unicode(iconv("GB2312","UTF-8",$v)).";";
?>

// utf8 -> unicode
function utf8_unicode($c) {
  switch(strlen($c)) {
    case 1:
      return ord($c);
    case 2:
      $n = (ord($c[0]) & 0x3f)       $n += ord($c[1]) & 0x3f;
      return $n;
    case 3:
      $n = (ord($c[0]) & 0x1f)       $n += (ord($c[1]) & 0x3f)       $n += ord($c[2]) & 0x3f;
      return $n;
    case 4:
      $n = (ord($c[0]) & 0x0f)       $n += (ord($c[1]) & 0x3f)       $n += (ord($c[2]) & 0x3f)       $n += ord($c[3]) & 0x3f;
      return $n;
  }
}
?>

下面的例子是利用php将uft-8这中编码转换为gb2312.

$str = "TTL全天候自动聚焦";
$str = preg_replace("|([0-9]{1,5});|", "\".u2utf82gb(\\1).\"", $str);
$str = "\$str=\"$str\";";
eval($str);
echo $str;
function u2utf82gb($c){
    $str="";
    if ($c          $str.=$c;
    } else if ($c          $str.=chr(0xC0 | $c>>6);
         $str.=chr(0x80 | $c & 0x3F);
    } else if ($c          $str.=chr(0xE0 | $c>>12);
         $str.=chr(0x80 | $c>>6 & 0x3F);
         $str.=chr(0x80 | $c & 0x3F);
    } else if ($c          $str.=chr(0xF0 | $c>>18);
         $str.=chr(0x80 | $c>>12 & 0x3F);
         $str.=chr(0x80 | $c>>6 & 0x3F);
         $str.=chr(0x80 | $c & 0x3F);
    }
    return iconv('UTF-8', 'GB2312', $str);
}
?>

或者是

function unescape($str) {
  $str = rawurldecode($str);
  preg_match_all("/(?:%u.{4})|.{4};|\d+;|.+/U",$str,$r);
  $ar = $r[0];
print_r($ar);
  foreach($ar as $k=>$v) {
    if(substr($v,0,2) == "%u")
      $ar[$k] = iconv("UCS-2","GB2312",pack("H4",substr($v,-4)));
    elseif(substr($v,0,3) == "")
      $ar[$k] = iconv("UCS-2","GB2312",pack("H4",substr($v,3,-1)));
    elseif(substr($v,0,2) == "") {
echo substr($v,2,-1)."
";
      $ar[$k] = iconv("UCS-2","GB2312",pack("n",substr($v,2,-1)));
    }
  }
  return join("",$ar);
}
$str = "TTL全天候自动聚焦";
echo unescape($str); file://out TTL全天候自动聚焦

利用javascript来转换

下面是一个显示所有全角半角的字体的查看例子

<script><br/>function showUni(min,max){<br/>show.document.open();<br/>show.document.writeln("<style>body{font-size:9pt;word-break:break-all;}");<br/>show.document.writeln(min + " - " + max + "<br><br>");<br/>var i=0;<br/>for(i=min;i<=max;i++){<br/> show.document.write("&#" + i + ";");<br/>}<br/>show.document.close();<br/>}<br/></script>








自定义： -

下面是一个查表(gb2312),转换gb2312到utf8的例子, 现在有iconv函数,这个已经没有太大的意义了,

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          $str.=$c;
    } else if ($c          $str.=chr(0xC0 | $c>>6);
         $str.=chr(0x80 | $c & 0x3F);
    } else if ($c          $str.=chr(0xE0 | $c>>12);
         $str.=chr(0x80 | $c>>6 & 0x3F);
         $str.=chr(0x80 | $c & 0x3F);
    } else if ($c          $str.=chr(0xF0 | $c>>18);
         $str.=chr(0x80 | $c>>12 & 0x3F);
         $str.=chr(0x80 | $c>>6 & 0x3F);
         $str.=chr(0x80 | $c & 0x3F);
    }
    return $str;
}
?>