/**
 * Genera la cadena siguiente a una cadena de caracteres alphanumericos no simbolicos ingresada
 * 
 * @author Cristián Pérez
 * @param string $current
 * @return string
 * 
 */
function getNextKey($current)
{
	$chars = array();
 
	for($i = 0; $i < strlen($current); $i++)
	{
		$chars[$i] = ord(substr($current, $i, 1));
	}
 
	$ci = count($chars) - 1;
 
	for($i = $ci;;$i--)
	{
		if(($chars[$i] >= 48 && $chars[$i] < 57) || (($chars[$i] >= 65 && $chars[$i] < 90) xor ($chars[$i] >= 97 && $chars[$i] < 122)))
		{
			++$chars[$i];
			break;
		}
 
		if($chars[$i] == 57)
		{
			$chars[$i] = 65;
			break;
		}
		elseif($chars[$i] == 90)
		{
			$chars[$i] = 97;
			break;
		}
 
 
		if($i == 0)
		{
			if($chars[$i] == 122)
			{
				foreach($chars as &$char)
				{
					$char = 48;
				}
 
				$chars[count($chars)] = 48;
			}
			break;
		}
		else
		{
			$chars[$i] = 48;
		}
	}
 
	foreach($chars as &$char)
	{
		$char = chr($char);
	}
 
	return implode('', $chars);
}

$form = '<form action="" method="post">';
$form .= '<input type="text" name="currentID" value="%s" />';
$form .= '<input type="submit" value="Siguiente ID" />';
$form .= '</form>';
 
if ($_POST)
{
	printf($form, getNextKey($_POST['currentID']));
}
else
{
	printf($form, '0');
}

/**
 * @name Get Method Scope
 * @param mixed $class ClassName u Object
 * @param string $method
 * @return integer
 * 
 * @author Cristián Pérez
 * 
 * $class puede ser un objeto tambien
 * La funcion devuelve
 * 0: Si el metodo o la clase (u objeto) no existen
 * 1: Si el metodo existe pero es privado
 * 2: Si el metodo existe y es publico!
 * 
 **/
function method_scope ($class, $method)
{
	$all = (array)get_class_methods ($class);
	if (! in_array ($method, $all))
	{
		if (method_exists ($class, $method))
			return 1; //Private
 
		return 0; //It doesn't exists
	}
 
	return 2; //Public
}

$scope = method_scope ($objeto, "miMetodo");
 
if ($scope == 2)
{
    echo 'El metodo es Publico';
}

/**
 * Remove a non empty directory
 * @author Cristián Pérez
 * @param string $path Folder Path
 * @return bool
 */
function removeDirectory($path)
{
    $path = rtrim( strval( $path ), '/' ) ;
 
    $d = dir( $path );
 
    if( ! $d )
        return false;
 
    while ( false !== ($current = $d->read()) )
    {
        if( $current === '.' || $current === '..')
            continue;
 
        $file = $d->path . '/' . $current;
 
        if( is_dir($file) )
            removeDirectory($file);
 
        if( is_file($file) )
            unlink($file);
    }
 
    rmdir( $d->path );
    $d->close();
    return true;
}

removeDirectory("/path/to/dir");

function forceDownload( $filePath )
{
    if( is_readable($filePath) )
    {
        header("Content-type: application/octet-stream");
        header("Content-Disposition: attachment; filename=\"$filePath\"\n");
        $fp = fopen($filePath, "r");
        fpassthru( $fp );
        exit();
    }
    else
    {
        echo 'Archivo no existente o sin permisos de lectura';
    }
}

forceDownload("/path/to/file.jpg");

function repeatedElements($array)
 
{
    $repeated = array();
 
 
    foreach( (array)$array as $value )
    {
        $inArray = false;
 
        foreach( $repeated as $i => $rItem )
        {
            if( $rItem['value'] === $value )
            {
                $inArray = true;
                ++$repeated[$i]['count'];
            }
        }
 
        if( false === $inArray )
        {
            $i = count($repeated);
            $repeated[$i] = array();
            $repeated[$i]['value'] = $value;
            $repeated[$i]['count'] = 1;
        }
    }
 
 
    foreach( $repeated as $i => $rItem )
    {
        if($rItem['count'] === 1)
        {
            unset($repeated[$i]);
        }
    }
 
    sort($repeated);
 
    return $repeated;
 
}

$arrayParaChequear = array("hola", "chau", "chau", "hola", 1, 5, 3, 1);
 
$repetidos = repeatedElements($arrayParaChequear);
 
print_r($repetidos);

Array
(
    [0] => Array
        (
            [value] => chau
            [count] => 2
        )
 
    [1] => Array
        (
            [value] => hola
            [count] => 2
        )
 
    [2] => Array
        (
            [value] => 1
            [count] => 2
        )
 
)