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:

/**
 * Converts CIDR numbers to valid network mask numbers.
 * 
 * @param cidr      CIDR number. (Required)
 * @return Returns a string. 
 * @author Sufiyan bin Yasa (cinod_79@yahoo.com) 
 * @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;
}