Add a new cidr class

resources/classes/cidr.php

@@ -0,0 +1,44 @@
+<?php
+
+/**
+ * cidr class
+ * 
+ * Classless Inter-Domain Routing is way to represent an abreviated subnet mask
+ */
+class cidr {
+
+	/**
+	 * Checks if the $ip_address is within the range of the given $cidr
+	 *
+	 * @param string|array $cidr_range string or array of CIDR addresses
+	 * @param string $ip_address The IP address used to check
+	 *
+	 * @return bool return true if the IP address is in CIDR or if it is empty
+	 */
+	public static function find($cidr, string $ip_address): bool {
+
+		//no cidr restriction
+		if (empty($cidr)) {
+			return true;
+		}
+
+		//check to see if the user's remote address is in the cidr array
+		if (is_array($cidr)) {
+			//cidr is an array
+			foreach ($cidr as $value) {
+				if (self::find($value, $ip_address)) {
+					return true;
+				}
+			}
+		} else {
+			//cidr is a string
+			list($subnet, $mask) = explode('/', $cidr);
+			return (ip2long($ip_address) & ~((1 << (32 - $mask)) - 1)) == ip2long($subnet);
+		}
+
+		//value not found in cidr
+		return false;
+	}
+
+
+}