As designing a new platform we tried to integrate the IBAN numbers. We have to make sure that the IBAN is validated and the IBAN stored to the database is always correct. So what would be a proper way to validate the number?
As the logic was explained in my other question, I've created a function myself. Based on the logic explained in the Wikipedia article find a proper function below. Country specific validation.
Algorithm and character lengths per country at https://en.wikipedia.org/wiki/International_Bank_Account_Number#Validating_the_IBAN.
function checkIBAN($iban)
{
if(strlen($iban) < 5) return false;
$iban = strtolower(str_replace(' ','',$iban));
$Countries = array('al'=>28,'ad'=>24,'at'=>20,'az'=>28,'bh'=>22,'be'=>16,'ba'=>20,'br'=>29,'bg'=>22,'cr'=>21,'hr'=>21,'cy'=>28,'cz'=>24,'dk'=>18,'do'=>28,'ee'=>20,'fo'=>18,'fi'=>18,'fr'=>27,'ge'=>22,'de'=>22,'gi'=>23,'gr'=>27,'gl'=>18,'gt'=>28,'hu'=>28,'is'=>26,'ie'=>22,'il'=>23,'it'=>27,'jo'=>30,'kz'=>20,'kw'=>30,'lv'=>21,'lb'=>28,'li'=>21,'lt'=>20,'lu'=>20,'mk'=>19,'mt'=>31,'mr'=>27,'mu'=>30,'mc'=>27,'md'=>24,'me'=>22,'nl'=>18,'no'=>15,'pk'=>24,'ps'=>29,'pl'=>28,'pt'=>25,'qa'=>29,'ro'=>24,'sm'=>27,'sa'=>24,'rs'=>22,'sk'=>24,'si'=>19,'es'=>24,'se'=>24,'ch'=>21,'tn'=>24,'tr'=>26,'ae'=>23,'gb'=>22,'vg'=>24);
$Chars = array('a'=>10,'b'=>11,'c'=>12,'d'=>13,'e'=>14,'f'=>15,'g'=>16,'h'=>17,'i'=>18,'j'=>19,'k'=>20,'l'=>21,'m'=>22,'n'=>23,'o'=>24,'p'=>25,'q'=>26,'r'=>27,'s'=>28,'t'=>29,'u'=>30,'v'=>31,'w'=>32,'x'=>33,'y'=>34,'z'=>35);
if(array_key_exists(substr($iban,0,2), $Countries) && strlen($iban) == $Countries[substr($iban,0,2)]){
$MovedChar = substr($iban, 4).substr($iban,0,4);
$MovedCharArray = str_split($MovedChar);
$NewString = "";
foreach($MovedCharArray AS $key => $value){
if(!is_numeric($MovedCharArray[$key])){
if(!isset($Chars[$MovedCharArray[$key]])) return false;
$MovedCharArray[$key] = $Chars[$MovedCharArray[$key]];
}
$NewString .= $MovedCharArray[$key];
}
if(bcmod($NewString, '97') == 1)
{
return true;
}
}
return false;
}
Slight modification of #PeterFox answer including support for bcmod() when bcmath is not available,
<?php
function isValidIBAN ($iban) {
$iban = strtolower($iban);
$Countries = array(
'al'=>28,'ad'=>24,'at'=>20,'az'=>28,'bh'=>22,'be'=>16,'ba'=>20,'br'=>29,'bg'=>22,'cr'=>21,'hr'=>21,'cy'=>28,'cz'=>24,
'dk'=>18,'do'=>28,'ee'=>20,'fo'=>18,'fi'=>18,'fr'=>27,'ge'=>22,'de'=>22,'gi'=>23,'gr'=>27,'gl'=>18,'gt'=>28,'hu'=>28,
'is'=>26,'ie'=>22,'il'=>23,'it'=>27,'jo'=>30,'kz'=>20,'kw'=>30,'lv'=>21,'lb'=>28,'li'=>21,'lt'=>20,'lu'=>20,'mk'=>19,
'mt'=>31,'mr'=>27,'mu'=>30,'mc'=>27,'md'=>24,'me'=>22,'nl'=>18,'no'=>15,'pk'=>24,'ps'=>29,'pl'=>28,'pt'=>25,'qa'=>29,
'ro'=>24,'sm'=>27,'sa'=>24,'rs'=>22,'sk'=>24,'si'=>19,'es'=>24,'se'=>24,'ch'=>21,'tn'=>24,'tr'=>26,'ae'=>23,'gb'=>22,'vg'=>24
);
$Chars = array(
'a'=>10,'b'=>11,'c'=>12,'d'=>13,'e'=>14,'f'=>15,'g'=>16,'h'=>17,'i'=>18,'j'=>19,'k'=>20,'l'=>21,'m'=>22,
'n'=>23,'o'=>24,'p'=>25,'q'=>26,'r'=>27,'s'=>28,'t'=>29,'u'=>30,'v'=>31,'w'=>32,'x'=>33,'y'=>34,'z'=>35
);
if (strlen($iban) != $Countries[ substr($iban,0,2) ]) { return false; }
$MovedChar = substr($iban, 4) . substr($iban,0,4);
$MovedCharArray = str_split($MovedChar);
$NewString = "";
foreach ($MovedCharArray as $k => $v) {
if ( !is_numeric($MovedCharArray[$k]) ) {
$MovedCharArray[$k] = $Chars[$MovedCharArray[$k]];
}
$NewString .= $MovedCharArray[$k];
}
if (function_exists("bcmod")) { return bcmod($NewString, '97') == 1; }
// http://au2.php.net/manual/en/function.bcmod.php#38474
$x = $NewString; $y = "97";
$take = 5; $mod = "";
do {
$a = (int)$mod . substr($x, 0, $take);
$x = substr($x, $take);
$mod = $a % $y;
}
while (strlen($x));
return (int)$mod == 1;
}
The accepted answer is not the preferred way of validation. The specification dictates the following:
Check that the total IBAN length is correct as per the country. If not, the IBAN is invalid
Replace the two check digits by 00 (e.g. GB00 for the UK)
Move the four initial characters to the end of the string
Replace the letters in the string with digits, expanding the string as necessary, such that A or a = 10, B or b = 11, and Z or z = 35. Each alphabetic character is therefore replaced by 2 digits
Convert the string to an integer (i.e. ignore leading zeroes)
Calculate mod-97 of the new number, which results in the remainder
Subtract the remainder from 98, and use the result for the two check digits. If the result is a single digit number, pad it with a leading 0 to make a two-digit number
I've written a class that validates, formats and parses strings according to the spec. Hope this helps some save the time required to roll their own.
The code can be found on GitHub here.
top rated function does NOT work.
Just try a string with '%' in it...
I'm using this one :
function checkIBAN($iban) {
// Normalize input (remove spaces and make upcase)
$iban = strtoupper(str_replace(' ', '', $iban));
if (preg_match('/^[A-Z]{2}[0-9]{2}[A-Z0-9]{1,30}$/', $iban)) {
$country = substr($iban, 0, 2);
$check = intval(substr($iban, 2, 2));
$account = substr($iban, 4);
// To numeric representation
$search = range('A','Z');
foreach (range(10,35) as $tmp)
$replace[]=strval($tmp);
$numstr=str_replace($search, $replace, $account.$country.'00');
// Calculate checksum
$checksum = intval(substr($numstr, 0, 1));
for ($pos = 1; $pos < strlen($numstr); $pos++) {
$checksum *= 10;
$checksum += intval(substr($numstr, $pos,1));
$checksum %= 97;
}
return ((98-$checksum) == $check);
} else
return false;
}
I found this solution in cakephp 3.7 validation class. Plain beautiful php realization.
/**
* Check that the input value has a valid International Bank Account Number IBAN syntax
* Requirements are uppercase, no whitespaces, max length 34, country code and checksum exist at right spots,
* body matches against checksum via Mod97-10 algorithm
*
* #param string $check The value to check
*
* #return bool Success
*/
public static function iban($check)
{
if (!preg_match('/^[A-Z]{2}[0-9]{2}[A-Z0-9]{1,30}$/', $check)) {
return false;
}
$country = substr($check, 0, 2);
$checkInt = intval(substr($check, 2, 2));
$account = substr($check, 4);
$search = range('A', 'Z');
$replace = [];
foreach (range(10, 35) as $tmp) {
$replace[] = strval($tmp);
}
$numStr = str_replace($search, $replace, $account . $country . '00');
$checksum = intval(substr($numStr, 0, 1));
$numStrLength = strlen($numStr);
for ($pos = 1; $pos < $numStrLength; $pos++) {
$checksum *= 10;
$checksum += intval(substr($numStr, $pos, 1));
$checksum %= 97;
}
return ((98 - $checksum) === $checkInt);
}
This function check the IBAN and need GMP activate http://php.net/manual/en/book.gmp.php.
function checkIban($string){
$to_check = substr($string, 4).substr($string, 0,4);
$converted = '';
for ($i = 0; $i < strlen($to_check); $i++){
$char = strtoupper($to_check[$i]);
if(preg_match('/[0-9A-Z]/',$char)){
if(!preg_match('/\d/',$char)){
$char = ord($char)-55;
}
$converted .= $char;
}
}
// prevent: "gmp_mod() $num1 is not an integer string" error
$converted = ltrim($converted, '0');
return strlen($converted) && gmp_strval(gmp_mod($converted, '97')) == 1;
}
enjoy !
The string of the hexadecimal number is like: 0X1.05P+10
The real value of this hexadecimal number is:1044.0
I can convert it using C language with method strtod.
But I can't find the way to convert it in PHP. Can somebody show me how to do it?
value string list:
1. "0X1.FAP+9"
2. "0X1.C4P+9"
3. "0X1.F3P+9"
4. "0X1.05P+10"
I think you'll have to make a custom function for this. So because I'm feeling nice today I custom-made one for you:
function strtod($hex) {
preg_match('#([\da-f]+)\.?([\da-f]*)p#i', $hex, $parts);
$i = 0;
$fractional_part = array_reduce(str_split($parts[2]), function($sum, $part) use (&$i) {
$sum += hexdec($part) * pow(16, --$i);
return $sum;
});
$decimal = (hexdec($parts[1]) + $fractional_part) * pow(2, array_pop(explode('+', $hex)));
return $decimal;
}
foreach(array('0X1.FAP+9', '0X1.C4P+9', '0X1.F3P+9', '0X1.05P+10', '0X1P+0') as $hex) {
var_dump(strtod($hex));
};
For versions below PHP 5.3:
function strtod($hex) {
preg_match('#([\da-f]+)\.?([\da-f]*)p#i', $hex, $parts);
$fractional_part = 0;
foreach(str_split($parts[2]) as $index => $part) {
$fractional_part += hexdec($part) * pow(16, ($index + 1) * -1);
}
$decimal = (hexdec($parts[1]) + $fractional_part) * pow(2, array_pop(explode('+', $hex)));
return $decimal;
}
foreach(array('0X1.FAP+9', '0X1.C4P+9', '0X1.F3P+9', '0X1.05P+10', '0X1P+0') as $hex) {
var_dump(strtod($hex));
};
hexdec(0X1.05P+10)
OK so that looks wrong to me as that doesn't look like a proper hex number but its the hexdec() function you want in php http://php.net/manual/en/function.hexdec.php
echo hexdec("0X1FAP")+9
echo hexdec("0X1C4P")+9
echo hexdec("0X1F3P")+9
echo hexdec("0X105P")+10
decimal = hex
(1044.0)10 = (414)16
We are looking for the Nth root in PHP. We need to do this with a very large number, and the windows calculator returns 2. With the following code we are getting 1. Does anybody have an idea how this works?
echo bcpow(18446744073709551616, 1/64);
Well it seems that PHP and the BC lib has some limits, and after searching on the internet i found this interesting article/code:
So you should use this function:
<?php
function NRoot($num, $n) {
if ($n<1) return 0; // we want positive exponents
if ($num<=0) return 0; // we want positive numbers
if ($num<2) return 1; // n-th root of 1 or 2 give 1
// g is our guess number
$g=2;
// while (g^n < num) g=g*2
while (bccomp(bcpow($g,$n),$num)==-1) {
$g=bcmul($g,"2");
}
// if (g^n==num) num is a power of 2, we're lucky, end of job
if (bccomp(bcpow($g,$n),$num)==0) {
return $g;
}
// if we're here num wasn't a power of 2 :(
$og=$g; // og means original guess and here is our upper bound
$g=bcdiv($g,"2"); // g is set to be our lower bound
$step=bcdiv(bcsub($og,$g),"2"); // step is the half of upper bound - lower bound
$g=bcadd($g,$step); // we start at lower bound + step , basically in the middle of our interval
// while step!=1
while (bccomp($step,"1")==1) {
$guess=bcpow($g,$n);
$step=bcdiv($step,"2");
$comp=bccomp($guess,$num); // compare our guess with real number
if ($comp==-1) { // if guess is lower we add the new step
$g=bcadd($g,$step);
} else if ($comp==1) { // if guess is higher we sub the new step
$g=bcsub($g,$step);
} else { // if guess is exactly the num we're done, we return the value
return $g;
}
}
// whatever happened, g is the closest guess we can make so return it
return $g;
}
echo NRoot("18446744073709551616","64");
?>
Hope this was helpful ...
I had problems with HamZa's solution getting to work with arbitrary precission, so i adopted it a little.
<?php
function NthRoot($Base, $NthRoot, $Precision = 100) {
if ($NthRoot < 1) return 0;
if ($Base <= 0) return 0;
if ($Base < 2) return 1;
$retVal = 0;
$guess = bcdiv($Base, 2, $Precision);
$continue = true;
$step = bcdiv(bcsub($Base, $guess, $Precision), 2, $Precision);
while ($continue) {
$test = bccomp($Base, bcpow($guess, $NthRoot, $Precision), $Precision);
if ($test == 0) {
$continue = false;
$retVal = $guess;
}
else if ($test > 0) {
$step = bcdiv($step, 2, $Precision);
$guess = bcadd($guess, $step, $Precision);
}
else if ($test < 0) {
$guess = bcsub($guess, $step, $Precision);
}
if (bccomp($step, 0, $Precision) == 0) {
$continue = false;
$retVal = $guess;
}
}
return $retVal;
}