php compare float numbers with input field value - php

Question

I have a form in which users can enter floating point values. I post these values to a php script and i compare if the numbers the users entered are between some values. If i post an integer the comparison returns true no matter if the number exceeded the boundaries. If i entere a floating point number the comparison fails no matter if the number is within the boundaries. I am not stupid, i've done floating point comparisons in c++ and i know how to do an if( float1 >= float2) return false...
here is my code:
//loading the helper
$val = Loader::helper('synerciel_form','synerciel_client');
//adding the fields to the inputs array for validation
$val->between('isolation_des_murs_peripheriques', 2.8, null, t($between.'Isolation des murs
pèriphèriques'), true, false);
//helper class
class SynercielFormHelper extends ValidationFormHelper {
const VALID_BETWEEN = 7;
const VALID_FLOAT = 7;
private $min;
private $max;
private $includeLow;
private $includeHigh;
public function between($field, $min, $max, $errorMsg, $includeLow = true, $includeHigh = true) {
$const = SynercielFormHelper::VALID_BETWEEN;
$this->min = $min;
$this->max = $max;
$this->includeLow = $includeLow;
$this->includeHigh = $includeHigh;
$this->addRequired($field, $errorMsg, $const);
}
...
public function test() {
$between = new ValidationNumbersBetweenHelper();
if (!$between->between($this->data[$field], $this->min, $this->max, $this->includeLow, $this->includeHigh)) {
$this->fieldsInvalid[] = $f;
}
}
My validation method (i believe here is the tricky part)
class ValidationNumbersBetweenHelper {
public function between($data, $min = null, $max = null, $includeLow = true, $includeHigh = true) {
if ($min && $includeLow) {
if (!($data >= $min))
return false;
} else if ($min) {
if (!($data > $min))
return false;
}
if ($max && $includeHigh) {
if (!($data <= $max))
return false;
} else if ($max) {
if (!($data < $max))
return false;
}
return true;
}
}

Answer 1

Check the warning message http://php.net/manual/en/language.operators.comparison.php
You can use BC Math Functions http://php.net/manual/en/function.bccomp.php
$status = bccomp($left, $right);
if ($status == 0) {
echo 'equal';
} else if ($status > 0) {
echo 'left bigger than right';
} else {
echo 'right bigger than left';
}
Hope this helps

Answer 2

Try isolating the troublesome code. Put your validation function into a stand-alone PHP file and test it there. Try checking $max and $min for !== null as 0 is also false. You could reverse the logic and remove all the !s. (e.g. change >= to <) so instead of "not greater than or equal to" you can have "less than"