006-PHP common function encapsulation

<?php

/**
 * 获取来访者的真实IP
 */
function getRealIp() {
    static $realip = null;
    if($realip !== null) {
        return $realip;
    }

    if(getenv(&#39;REMOTE_ADDR&#39;)) {
        $realip = getenv(&#39;REMOTE_ADDR&#39;);
    } else if(getenv(&#39;HTTP_CLIENT_IP&#39;)) {
        $realip = getenv(&#39;HTTP_CLIENT_IP&#39;);
    } else if (getenv(&#39;HTTP_X_FROWARD_FOR&#39;)) {
        $realip = getenv(&#39;HTTP_X_FROWARD_FOR&#39;);
    }

    return $realip;
}


/**
 * 生成随机字符串
 * @param int $num 生成的随机字符串的个数
 * @return str 生成的随机字符串
 * echo randStr();
 */
function randStr($num=6) {
    $str = str_shuffle(&#39;abcedfghjkmnpqrstuvwxyzABCEDFGHJKMNPQRSTUVWXYZ23456789&#39;);
    return substr($str, 0 , $num);
}


/**
 * 创建目录 ROOT.&#39;/upload/2015/01/25/qwefas.jpg&#39;
 */
function createDir() {
    $path = &#39;/upload/&#39;.date(&#39;Y/m/d&#39;);
    $fpath = ROOT . $path;
    if(is_dir($fpath) || mkdir($fpath , 0777 , true)) {
        return $path;
    } else {
        return false;
    }
}


/**
 * 获取文件后缀
 * @param str $filename 文件名
 * @return str 文件的后缀名,且带点.
 */
function getExt($filename) {
    return strrchr($filename, &#39;.&#39;);
}


/**
 * 生成缩略图
 *
 * @param str $oimg /upload/2016/01/25/asdfed.jpg
 * @param int $sw 生成缩略图的宽
 * @param int $sh 生成缩略图的高
 * @return str 生成缩略图的路径 /upload/2016/01/25/asdfed.png
 */
function makeThumb($oimg , $sw=200 , $sh = 200) {
    //缩略图存放的路径的名称
    $simg = dirname($oimg) . &#39;/&#39; . randStr() . &#39;.png&#39;;

    //获取大图和缩略图的绝对路径
    $opath = ROOT . $oimg;//原图的绝对路径
    $spath = ROOT . $simg;//最终生成的小图

    //创建小画布
    $spic = imagecreatetruecolor($sw, $sh);

    //创建白色
    $white = imagecolorallocate($spic, 255, 255, 255);
    imagefill($spic, 0, 0, $white);

    //获取大图信息
    list($bw , $bh ,$btype) = getimagesize($opath);

    //1 = GIF，2 = JPG，3 = PNG，4 = SWF，5 = PSD，6 = BMP，
    //7 = TIFF(intel byte order)，8 = TIFF(motorola byte order)，9 = JPC，10 = JP2，
    //11 = JPX，12 = JB2，13 = SWC，14 = IFF，15 = WBMP，16 = XBM
    $map = array(
        1=>&#39;imagecreatefromgif&#39;,
        2=>&#39;imagecreatefromjpeg&#39;,
        3=>&#39;imagecreatefrompng&#39;,
        15=>&#39;imagecreatefromwbmp&#39;
    );
    if(!isset($map[$btype])) {
        return false;
    }

    //imagecreatefromjpeg(filename)
    $opic = $map[$btype]($opath);//大图资源

    //计算缩略比
    $rate = min($sw/$bw , $sh/$bh);
    $zw = $bw * $rate;//最终返回的小图宽
    $zh = $bh * $rate;//最终返回的缩略小图高

    //imagecopyresampled(dst_image, src_image, dst_x, dst_y,
    //src_x, src_y, dst_w, dst_h, src_w, src_h)
    //echo $rate ,  &#39;<br>&#39; , $zw , &#39;<br>&#39; , $zh ;exit();

    //拷贝图像并修改大小
    //imagecopyresampled($spic, $opic, 0, 0, 0, 0, $zw, $zh, $bw, $bh);
    imagecopyresampled($spic, $opic, ($sw-$zw)/2, ($sh-$zh)/2, 0, 0, $zw, $zh, $bw, $bh);

    //输出/保存图形
    imagepng($spic , $spath);

    //销毁画布(关闭画板)
    imagedestroy($spic);
    imagedestroy($opic);

    return $simg;
}


/**
 * 转义字符串{ 对POST,GET,COOKIE数组进行转义 }
 * @param $arr
 * @return mixed
 */
function _addslashes($arr){
    foreach ($arr as $k=>$v){
        if(is_string($v)){
            $arr[$k] = addslashes($v);
        }elseif(is_array($v)){
            $arr[$k] = _addslashes($v);
        }
    }
    return $arr;
}