<?php 

class class_utility {

	/*
	Utility
	Damon Vaughn Caskey
	2013-01-09
	
	Miscellaneous utility functions.
	*/
	
	public function utl_color_alternation($i, $cColorEven="#DDDDFF", $cColorOdd="#CECEFF")
	{		
		/*
		back_alt_0001 - https://www.caskeys.com/dc/?p=4900
		Damon Vaughn Caskey
		2012-10-18
		
		Output alternating background colors for even/odd rows in tables or other types of layouts.
		
		$i:				Current row/location/count. 
		$cColorEven:	Color to output if $i is an even number.
		$cColorEven:	Color to output if $i is an odd number.
		*/
		
		if($i%2)				//Even number?
		{				
			return $cColorEven;	//Return even color.
		}
		else
		{	
			return $cColorOdd;	//Return odd color.
		}
	}
	
	public function utl_get_get($cID, $cDefault=NULL)
	{
		/*
		utl_get_get
		Damon Vaughn Caskey
		2013-01-01
		
		Wrapper to obtain get value.
		
		$cID:		Index.
		$cDefault:	Default on not set.
		*/
		
		return $this->utl_validate_isset($_GET[$cID], $cDefault);
	}
	
	public function utl_get_post($cID, $cDefault=NULL)
	{
		/*
		utl_get_post
		Damon Vaughn Caskey
		2013-01-01
		
		Wrapper to obtain post value.
		
		$cID:		Index.
		$cDefault:	Default on not set.
		*/
		//echo $_POST[$cID];
		
		return $this->utl_validate_isset($_POST[$cID], $cDefault);
	}
	
	public function utl_get_server_value($cID, $cDefault=NULL)
	{
		/*
		utl_get_server_value
		Damon Vaughn Caskey
		2013-01-01
		
		Wrapper to obtain server value.
		
		$cID:		Index.
		$cDefault:	Default on not set.
		*/
		
		return $this->utl_validate_isset($_SERVER[$cID], $cDefault);
	}
	
	public function utl_str_to_array($cList=NULL, $cDel=",")
	{	
		/*
		str_to_array
		Damon Vaughn Caskey
		2013-01-09
		
		Break string into indexed array with no spaces.
		
		$cList:	List array to break up.
		$cDel:	Delimiter.
		*/
	
		/*
		If list is populated remove spaces and break into array.
		*/
		if($cList)									//List populated?								
		{
			$cList = str_replace (" ", "", $cList);	//Remove spaces.
			$cList = explode($cDel, $cList);		//Break into array.
		}
		
		/*
		Return end result.
		*/
		return $cList;
	}
	
	public function utl_redirect($cURL=NULL)
	{	
		/*
		utl_redirect
		Damon Vaughn Caskey
		2013-01-09
		
		Send header that redirects client to new page.
		
		$cURL:	Target address.
		*/

		/*
		If headers haven't been sent, redirect user to an error page. Otherwise we'll just have to die and settle for a plain text message.
		*/
		
		if(headers_sent())
		{ 
			/*
			Good coding will always avoid attempting to resend headers, but let's make sure to catch them here before PHP throws a nasty error.
			*/			
		}
		else
		{			
			header('Location: '.$cURL);
			return TRUE;
		}
		
		/*
		Return end result.
		*/
		return FALSE;
	}
	
	public function utl_validate_email(&$cValue, $cDefault=NULL)
	{
		/*
		utl_validate_email
		Damon Vaughn Caskey
		2013_01_01
		
		Validate email variable.
		
		$cValue:	Email value.
		$cDefault:	Default on fail.
		*/
				
		if(filter_var($cValue, FILTER_VALIDATE_EMAIL)) 
		{			
			list($user,$domaine)=explode("@", $cValue, 2);
			
			if(!checkdnsrr($domaine, "MX")&& !checkdnsrr($domaine, "A"))
			{
				/*
				Bad domain.
				*/
				$cValue = FALSE;
			}
			else 
			{
				//Domain OK.
			}
		}
		else 
		{		
			/*
			Bad address.
			*/	
			$cValue = FALSE;
		} 
		
		if($cValue == FALSE)
		{
			$cValue = $cDefault;
		}
		
		return $cValue;
	}
	
	public function utl_validate_ip(&$cValue, $cDefault=NULL)
	{
		/*
		utl_validate_ip
		Damon Vaughn Caskey
		2013-01-01
		
		Validate ip variable.
		
		$cValue:	ip value.
		$cDefault:	Default on fail.
		*/
		
		$cValue = filter_var($cValue, FILTER_VALIDATE_IP);		
		
		if($cValue == FALSE)
		{
			$cValue = $cDefault;
		}
		
		return $cValue;
	}
	
	public function utl_validate_isset(&$cValue, $cDefault=NULL)
	{
		/*
		utl_validate_isset
		Damon Vaughn Caskey
		2013-01-01
		
		Return default if variable is not set.
		
		$cValue:	Value.
		$cDefault:	Default on not set.
		*/
		
		if(!isset($cValue))
		{
			$cValue = $cDefault;
		}
		
		return $cValue;
	}
	
	public function utl_if_exists($cValue, $cValPrefix=NULL, $cValCadence=NULL, $cAlt=NULL)
	{
		/*
		utl_
		Damon Vaughn Caskey
		2013-01-01
		
		Return self if self has a value, or $cAlt if $cValue is empty or null. Reduces need to retype and 
		potentiality mix up variable names or array keys twice in common "echo <X> if it has a value" situations.

		Preconditions:
			$cValue: Value to test and return if it exists.
			$cValPrefix: Add to front of $cValue on return.
			$cValCadence: Add to end of $cValue on return.
			$cAlt: Value to return if $cValue is NULL.
		*/
		
		/* Vaiables */
		$cReturn = $cAlt;	//Final value to return.
		
		/* Value exists? */
		if($cValue)
		{
			/* Tack on additions and return value. */			
			$cReturn = $cValPrefix.$cValue.$cValCadence;
		}
		
		return $cReturn;		
	}
}
?>