Code Examples -> Function that returns an IP Address if it's correct. IMPROVED!!!

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PHP Code Examples

Title :	Function that returns an IP Address if it's correct. IMPROVED!!!
Categories :	PHP, Algorithms, Network	J. Flor
Date :	Apr 02nd 2003
Grade :	3 of 5 (graded 5 times)
Viewed :	6943
File :	ipchecker-0.2.php
Images :	No Images for this code example.

Search :	More code by J. Flor
Action :	Grade This Code Example
Tools :	My Examples List

Code

<?php
/***************************************************************************
* ipchecker.php
*
* Wed Mar 31 11:20:01 2003
* Copyright 2003 peterflor
* Author : J. Pedro Flor
* E-Mail : peterflor@yahoo.com
*
* This function check the integrity of an IPv4 number.
* Also, allow to check octet by octet after first validation.
* The result value can be a plain "string" or (for more flexibility) an array.
*
* array = [octet-1][dot-1][octet-2][dot-2][octet-3][dot-3][octet-4]
* elements = [0] [1] [2] [3] [4] [5] [6]
* ==> A.B.C.D <==
*
* (Created with Anjuta)
*
****************************************************************************/

/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

/*
* TODO LIST
*
* First of all: correct my english and of course, correct variable names.
*
*/

// IPv4 PHP-Checker
function check_ip($ip_target) {

        $ip_target = trim ($ip_target);

        $pre_ip = array (0, ".", 0, ".", 0, ".", 0);

        $length = strlen ($ip_target);
        $counter = 0;
        $octet_number = 0;
        $temporal_octet = "";


        if (($length < 7) || ($length > 15)) {
                print ("Error.");
                exit;
        }

        while ($counter < $length) {
                if (ctype_digit ($ip_target[$counter]) == TRUE ) {
                                $temporal_octet = $temporal_octet. $ip_target[$counter];
                } else {
                        if ($ip_target[$counter] != ".") {
                                print ("Error.");
                                exit;
                        }
                        $pre_ip[$octet_number] = $temporal_octet;
                        $octet_number += 2;
                        $temporal_octet = "";
                }
                $counter++;
        }

        // Tips and dirty TRICKS :)

        // Getting Last octet
        $pre_ip[$octet_number] = $temporal_octet;

        if ((($pre_ip[0] < 1) || ($pre_ip[0] > 255)) ||
         (($pre_ip[count($pre_ip)-1] == "") ||
                ($pre_ip[count($pre_ip)-1] == "."))) {
                print ("Error.");
                exit;
        }

        for ($octet_number = 2; $octet_number < 7; $octet_number+=2) {
                if ((($pre_ip[$octet_number] < 0) ||
                ($pre_ip[$octet_number] > 255)) ||
                 (($pre_ip[$octet_number] == "") ||
                 ($pre_ip[$octet_number] == "."))) {
                        print ("Error.");
                        exit;
                }
        }

        //return $pre_ip; // Array
        return $ip_target; // Plain string
}
// Calling function
check_ip("1.25.255.1");
?>

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User Comments

	Adam Namejko wrote : 918 Could the function not be made more simple by using regular expression matching. I`m not the best out there, but this works I believe. function check_ip($ip_target) { $ip_target = trim($ip_target); $first_oct = `([1-9]\|[1-9][0-9]\|1[0-9]{0,2}\|2[0-4][0-9]\|25[0-5])`; $all_other_oct = `([0-9]\|[1-9][0-9]\|1[0-9]{0,2}\|2[0-4][0-9]\|25[0-5])`; $pattern = $first_oct . `\.` . $all_other_oct . `\.` . $all_other_oct . `\.` . $all_other_oct; if (!preg_match("/^$pattern$/", $ip_target)) { print(`Error.`); exit; } return $ip_target; }
	tomas dzurilla wrote :922 `hi, i was trying to use the function, but on the 20th (not counting comments) line there is an undefined function "ctype_digit". what is that function? thanks. t`