PHP, Common String Functions

class string
{
/**
* Checks to see if string is only alphabetic
*
* @static
* @param string $value
* @param boolean $ignore_spaces
* @return boolean
* @category string
*/
static function isAlpha($value, $ignore_spaces = false)
{
if (!isset($value{0}))
{
return false;
}
if ($ignore_spaces)
{
$value = str_replace(" ", "", $value);
}
return ctype_alpha($value);
}
/**
* Checks to see if string only contains letters and numbers
*
* @static
* @param string $value
* @param boolean $ignore_spaces
* @return boolean
* @category string
*/
static function isAlphaNum($value, $ignore_spaces = false)
{
if (!isset($value{0}))
{
return false;
}
if ($ignore_spaces)
{
$value = str_replace(" ", "", $value);
}
return ctype_alnum($value);
}
/**
* Checks to see if a string is a hex
* @param string $value
* @return boolean
*/
static function isHex($value)
{
if (!isset($value{0}))
{
return false;
}
return ctype_xdigit($value);
}
/**
* Checks to see if a string is numeric
*
* @static
* @param string $value
* @param boolean $ignore_spaces
* @return boolean
* @category string
*/
static function isNumeric($value, $ignore_spaces = false)
{
if (!isset($value{0}))
{
return false;
}
if ($ignore_spaces)
{
$value = str_replace(" ", "", $value);
}
return ctype_digit($value);
}
static function isDate($value)
{
if (!isset($value{0}))
{
return false;
}
if (strtotime($value) !== false)
{
return true;
}
else
{
return false;
}
}
/**
* Checks to see if string is a valid phone number
*
* @static
* @param string $value
* @return boolean
* @category string
*/
static function isPhone($value)
{
if (!isset($value{0}))
{
return false;
}
if(ereg("^([0-9]( |-)?)?(\(?[0-9]{3}\)?|[0-9]{3})( |-)?([0-9]{3}( |-)?[0-9]{4}|[a-zA-Z0-9]{7})$", $value))
{
return true;
}
else
{
return false;
}
}
/**
* Checks to see if a string is an email
*
* @static
* @param string $value
* @param boolean $check_domain
* @return boolean
* @category string
*/
public static function isEmail($value, $check_domain = false)
{
if (!isset($value{0}))
{
return false;
}
if(eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $value))
{
if ($check_domain == true)
{
list($userName, $mailDomain) = split("@", $value);
if (checkdnsrr($mailDomain, "MX")) {
return true;
}
else
{
return false;
}
}
return true;
}
else
{
return false;
}
}
/**
* Checks to see if a string is a valid zip code
*
* @static
* @param string $value
* @param boolean $extended
* @return boolean
* @category string
*/
static function isZip($value, $extended = false)
{
if (!isset($value{0}))
{
return false;
}
if (!$extended)
{
if(ereg("^[0-9]{5}$", $value))
{
return true;
}
else
{
return false;
}
}
else
{
if(ereg("^[0-9]{5}$", $value) || ereg("^[0-9]{5}-[0-9]{4}$", $value))
{
return true;
}
else
{
return false;
}
}
}
/**
* Validates credit card number
*
* @static
* @param string $value
* @return boolean
* @category string
*/
static function isCreditCard($value)
{
if (!isset($value{0}))
{
return false;
}
if (ereg("(^(4|5)\d{3}-?\d{4}-?\d{4}-?\d{4}|(4|5)\d{15})|(^(6011)-?\d{4}-?\d{4}-?\d{4}|(6011)-?\d{12})|(^((3\d{3}))-\d{6}-\d{5}|^((3\d{14})))", $value))
{
return true;
}
else
{
return false;
}
}
/**
* Strips html out of a string
*
* @static
* @param string $value
* @category string
*/
static function stripHTML(&$value)
{
if (!isset($value{0}))
{
exit;
}
$breaks[] = "<br>";
$breaks[] = "<br />";
$search = array('@<script[^>]*?>.*?</script>@si',  // Strip out javascript
'@<style[^>]*?>.*?</style>@siU'    // Strip style tags properly
);
$value = preg_replace($search, '', $value);
$value = str_ireplace($breaks, "\r\n", $value);
$value = trim($value);
$value = strip_tags($value);
$value = html_entity_decode($value, ENT_QUOTES);
$value = addslashes($value);
}
/**
* Cleans out script tags out of HTML
*
* @static
* @param string $value
* @category string
*/
static function cleanHTML(&$value)
{
$search = array('@<script[^>]*?>.*?</script>@si',  // Strip out javascript
'@<style[^>]*?>.*?</style>@siU'    // Strip style tags properly
);
$value = preg_replace($search, '', $value);
$value = htmlentities($value);
}
/**
* Encodes all non alpha numeric characters in a URL with the '%' sign
*
* @static
* @param string $url
* @return string
* @example string.php how to use;
* @category string
*/
static function UrlEncode($url)
{
if (strpos($url, '?') === false)
{
return $url;
}
else
{
$startpos  = strpos($url, "?");
$tmpurl    = substr($url, 0 , $startpos+1);
$qryStr    = substr($url, $startpos+1);
$qryvalues = explode("&", $qryStr);
foreach($qryvalues as $value)
{
$buffer    = explode("=", $value);
$buffer[1] = urlencode($buffer[1]);
$new_query_values[] = implode("=", $buffer);
}
$finalqrystr =implode("&", $new_query_values);
$finalURL    =$tmpurl . $finalqrystr;
return $finalURL;
}
}
/**
*
* @param $length
* @return string
*/
static function generateID($length)
{
$random_id_length = $length;
$rnd_id = crypt(uniqid(rand(),1));
$rnd_id = strip_tags(stripslashes($rnd_id));
$rnd_id = str_replace(".","",$rnd_id);
$rnd_id = strrev(str_replace("/","",$rnd_id));
$rnd_id = substr($rnd_id,0,$random_id_length);
return $rnd_id;
}
}