CFLib.org – Common Function Library Project

Description:
CIDR numbers such as /24,/32,/12 are converted to the appropiate netmask address form.

Return Values:
Returns a string.

Example:

#cidrToNetMask(24)#<br>
#cidrToNetMask(12)#<br>

Parameters:

Full UDF Source:

<cfscript>
/**
 * Converts CIDR numbers to valid network mask numbers.
 * 
 * @param cidr 	 CIDR number. (Required)
 * @return Returns a string. 
 * @author Sufiyan bin Yasa (&#99;&#105;&#110;&#111;&#100;&#95;&#55;&#57;&#64;&#121;&#97;&#104;&#111;&#111;&#46;&#99;&#111;&#109;) 
 * @version 1, July 19, 2005 
 */
function cidrToNetMask (cidr) {
	var netMask = "";	

	var post = 0;
	var remainder = cidr MOD 8;
	var divide = cidr \ 8;

	while(divide gt 0) {
		netMask = listAppend(netMask, 255,'.'); 
		divide = divide - 1;
		post = post + 1;		
	}

	if(remainder gt 0) {			
		netMask = listAppend(NetMask,
				  bitSHLN(BitOr(0,2^remainder-1), 8-remainder),
				  '.'); 		
		post = post +1;			
	}

	while(post lt 4) {
		netMask = listAppend(netMask, "0",'.'); 			
		post = post + 1;
	}
	
	if(right(netMask, 1) eq "."){		
		netMask = left(netMask,len(netMask));
	}
	return netMask;
}
</cfscript>