实例代码展示php常用的函数，实现一些功能总结

本文汇总了常用的php函数，包括获取客户端ip，字符串截取，下载等，详情请查看如下代码：

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 1) { // 多字节字符
  $return .= "%u" . strtoupper(bin2hex(mb_convert_encoding($str, 'UCS-2', $encoding)));
 } else {
  $return .= "%" . strtoupper(bin2hex($str));
 }
 }
 return $return;
}
/**
 * php 实现 js unescape函数
 * @param [type] $str [description]
 * @return [type]  [description]
 */
function unescape($str) {
 $str = rawurldecode($str);
 preg_match_all("/(?:%u.{4})|.{4};|\d+;|.+/U",$str,$r);
 $ar = $r[0];
 foreach($ar as $k=>$v) {
  if(substr($v,0,2) == "%u"){
   $ar[$k] = iconv("UCS-2","utf-8//IGNORE",pack("H4",substr($v,-4)));
  } elseif(substr($v,0,3) == "") {
   $ar[$k] = iconv("UCS-2","utf-8",pack("H4",substr($v,3,-1)));
  } elseif(substr($v,0,2) == "") {
   echo substr($v,2,-1)."";
   $ar[$k] = iconv("UCS-2","utf-8",pack("n",substr($v,2,-1)));
  }
 }
 return join("",$ar);
}

/**
 * 数字转人名币
 * @param [type] $num [description]
 * @return [type]  [description]
 */
function num2rmb ($num) {
 $c1 = "零壹贰叁肆伍陆柒捌玖";
 $c2 = "分角元拾佰仟万拾佰仟亿";
 $num = round($num, 2);
 $num = $num * 100;
 if (strlen($num) > 10) {
  return "oh,sorry,the number is too long!";
 }
 $i = 0;
 $c = "";
 while (1) {
  if ($i == 0) {
   $n = substr($num, strlen($num)-1, 1);
  } else {
   $n = $num % 10;
  }
  $p1 = substr($c1, 3 * $n, 3);
  $p2 = substr($c2, 3 * $i, 3);
  if ($n != '0' || ($n == '0' && ($p2 == '亿' || $p2 == '万' || $p2 == '元'))) {
   $c = $p1 . $p2 . $c;
  } else {
   $c = $p1 . $c;
  }
  $i = $i + 1;
  $num = $num / 10;
  $num = (int)$num;
  if ($num == 0) {
   break;
  }
 }
 $j = 0;
 $slen = strlen($c);
 while ($j < $slen) {
  $m = substr($c, $j, 6);
  if ($m == '零元' || $m == '零万' || $m == '零亿' || $m == '零零') {
   $left = substr($c, 0, $j);
   $right = substr($c, $j + 3);
   $c = $left . $right;
   $j = $j-3;
   $slen = $slen-3;
  }
  $j = $j + 3;
 }
 if (substr($c, strlen($c)-3, 3) == '零') {
  $c = substr($c, 0, strlen($c)-3);
 } // if there is a '0' on the end , chop it out
 return $c . "整";
}

/**
 * 特殊的字符
 * @param [type] $str [description]
 * @return [type]  [description]
 */
function makeSemiangle($str) {
 $arr = array(
  '０' => '0', '１' => '1', '２' => '2', '３' => '3', '４' => '4',
  '５' => '5', '６' => '6', '７' => '7', '８' => '8', '９' => '9',
  'Ａ' => 'A', 'Ｂ' => 'B', 'Ｃ' => 'C', 'Ｄ' => 'D', 'Ｅ' => 'E',
  'Ｆ' => 'F', 'Ｇ' => 'G', 'Ｈ' => 'H', 'Ｉ' => 'I', 'Ｊ' => 'J',
  'Ｋ' => 'K', 'Ｌ' => 'L', 'Ｍ' => 'M', 'Ｎ' => 'N', 'Ｏ' => 'O',
  'Ｐ' => 'P', 'Ｑ' => 'Q', 'Ｒ' => 'R', 'Ｓ' => 'S', 'Ｔ' => 'T',
  'Ｕ' => 'U', 'Ｖ' => 'V', 'Ｗ' => 'W', 'Ｘ' => 'X', 'Ｙ' => 'Y',
  'Ｚ' => 'Z', 'ａ' => 'a', 'ｂ' => 'b', 'ｃ' => 'c', 'ｄ' => 'd',
  'ｅ' => 'e', 'ｆ' => 'f', 'ｇ' => 'g', 'ｈ' => 'h', 'ｉ' => 'i',
  'ｊ' => 'j', 'ｋ' => 'k', 'ｌ' => 'l', 'ｍ' => 'm', 'ｎ' => 'n',
  'ｏ' => 'o', 'ｐ' => 'p', 'ｑ' => 'q', 'ｒ' => 'r', 'ｓ' => 's',
  'ｔ' => 't', 'ｕ' => 'u', 'ｖ' => 'v', 'ｗ' => 'w', 'ｘ' => 'x',
  'ｙ' => 'y', 'ｚ' => 'z',
  '（' => '(', '）' => ')', '〔' => '[', '〕' => ']', '【' => '[',
  '】' => ']', '〖' => '[', '〗' => ']', '｛' => '{', '｝' => '}', '《' => '<',
  '》' => '>',
  '％' => '%', '＋' => '+', '—' => '-', '－' => '-', '～' => '-',
  '：' => ':', '。' => '.', '、' => ',', '，' => '.', '、' => '.',
  '；' => ';', '？' => '?', '！' => '!', '…' => '-', '‖' => '|',
  '”' => '"', '“' => '"', ''' => '`', '‘' => '`', '｜' => '|', '〃' => '"',
  '　' => ' ','．' => '.');
 return strtr($str, $arr);
}

/**
 * 下载
 * @param [type] $filename [description]
 * @param string $dir  [description]
 * @return [type]   [description]
 */
function downloads($filename,$dir='./'){
 $filepath = $dir.$filename;
 if (!file_exists($filepath)){
  header("Content-type: text/html; charset=utf-8");
  echo "File not found!";
  exit;
 } else {
  $file = fopen($filepath,"r");
  Header("Content-type: application/octet-stream");
  Header("Accept-Ranges: bytes");
  Header("Accept-Length: ".filesize($filepath));
  Header("Content-Disposition: attachment; filename=".$filename);
  echo fread($file, filesize($filepath));
  fclose($file);
 }
}

/**
 * 创建一个目录树
 * @param [type] $dir [description]
 * @param integer $mode [description]
 * @return [type]  [description]
 */
function mkdirs($dir, $mode = 0777) {
 if (!is_dir($dir)) {
  mkdirs(dirname($dir), $mode);
  return mkdir($dir, $mode);
 }
 return true;
}