Example of method of PHP to implement Unicode encoding mutual conversion

<?php
/**
 * $str Original Chinese string
 * $encoding The encoding of the original string, default utf-8
 * $prefix encoded prefix, default "&#"
 * $postfix encoded suffix, default ";"
 */
function unicode_encode($str, $encoding = 'utf-8', $prefix = '&#', $postfix = ';') {
 //Split the string $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, $cind, 1)) < 0xA1) { //If it is English, take 1 byte  array_push($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", $row);
 }
 //Convert Unicode code foreach ($arr_cont as $key => $value) {
 $unicodestr.= $prefix . base_convert(bin2hex(iconv('utf-8', 'UCS-4', $value)), 16, 10) .$postfix;
 }
 return $unicodestr;
}
/**
 * $str Unicode encoded string
 * $decoding The encoding of the original string, default utf-8
 * $prefix The prefix of the encoded string, default "&#"
 * $postfix encoded string suffix, default ";"
 */
function unicode_decode($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 Programming:";
$unistr = unicode_encode($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 />';

function unicode_encode($name) {//Unicode encoding $jsonarr = array($name);
 $jsonstr = json_encode($jsonarr);
 if (empty ($jsonstr))
 return '';
 return substr($jsonstr,2,-2);
}
function unicode_decode($name) {//Unicode decoding
 $json = '{"str":"' . $name . '"}';
 $arr = json_decode($json, true);
 if (empty ($arr))
 return '';
 return $arr['str'];

}

$test = "\u811a\u672c\u4e4b\u5bb6";
echo "unicode decoding:".unicode_decode($test)."<br/>";
echo "unicode encoding:".unicode_encode('I')."<br/>";