PHP Unicode编码相互转换

<?php
/**
* $str 原始中文字符串
* $encoding 原始字符串的编码，默认utf-8
* $prefix 编码后的前缀，默认"&#"
* $postfix 编码后的后缀，默认";"
*/
function unicode_encode($str, $encoding = 'utf-8', $prefix = '&#', $postfix = ';') {
//将字符串拆分
$str = iconv("UTF-8", "gb2312", $str);
$cind = 0;
$arr_cont = array();

for ($i = 0; $i < strlen($str); $i++) {
if (strlen(substr($str, $cind, 1)) > 0) {
if (ord(substr($str, $cind, 1)) < 0xA1) { //如果为英文则取1个字节
array_push($arr_cont, substr($str, $cind, 1));
$cind++;
} else {
array_push($arr_cont, substr($str, $cind, 2));
$cind+=2;
}
}
}
foreach ($arr_cont as &$row) {
$row = iconv("gb2312", "UTF-8", $row);
}

//转换Unicode码
foreach ($arr_cont as $key => $value) {
$unicodestr.= $prefix . base_convert(bin2hex(iconv('utf-8', 'UCS-4', $value)), 16, 10) .$postfix;
}

return $unicodestr;
}

/**
* $str Unicode编码后的字符串
* $decoding 原始字符串的编码，默认utf-8
* $prefix 编码字符串的前缀，默认"&#"
* $postfix 编码字符串的后缀，默认";"
*/
function unicode_decode($unistr, $encoding = 'utf-8', $prefix = '&#', $postfix = ';') {
$arruni = explode($prefix, $unistr);
$unistr = '';
for ($i = 1, $len = count($arruni); $i < $len; $i++) {
if (strlen($postfix) > 0) {
$arruni[$i] = substr($arruni[$i], 0, strlen($arruni[$i]) - strlen($postfix));
}
$temp = intval($arruni[$i]);
$unistr .= ($temp < 256) ? chr(0) . chr($temp) : chr($temp / 256) . chr($temp % 256);
}
return iconv('UCS-2', $encoding, $unistr);
}

$str = "PHP二次开发：www.php2.cc";

$unistr = unicode_encode($str);
$unistr2 = unicode_decode($unistr);
echo $unistr . '<br />';
echo $unistr2 . '<br />';

$unistr = unicode_encode($str,'GBK','\\u');
$unistr2 = unicode_decode($unistr,'GBK','\\u');
echo $unistr . '<br />';
echo $unistr2 . '<br />';