An object oriented arbitrary precision arithmetic class for PHP (>5.3.3).

You can use Composer

To add this package as a local, per-project dependency to your project, simply add a dependency on rtlopez/decimal to your project's composer.json file. Here is a minimal example of a composer.json file that just defines a dependency on Decimal:

{
  "require": {
    "rtlopez/decimal": "^1.0"
  }
}

The Decimal class can be used for an arbitrary precision calculation. Main features are:

• Immutable result of each operation,
• The same result precision,
• Safe for finance calculations,
• Fluent interface,
• Many unit test (more than 1100 tests and 3700 assertions),
• Easy to use and install,

The Decimal solve several inconveniences known in other solutions.

• Float is only an aproximation and have limited precision,
• Fixed-point have limited size (64-bits on 64-bit system),
• Pure bcmath cannot correctly round, only truncate,
• GMP is not object-oriented

use RtLopez\Decimal;

$n1 = Decimal::create(123, 2);
$n2 = Decimal::create(123.45, 2); // not recommended
$n3 = Decimal::create('123.45', 2);
$n4 = Decimal::create($n1, 2);

$number = Decimal::create('12345.671', 2);

echo (string)$number;
// 12345.67

echo $number->format(1, ',', ' ');
// 12 345,7

echo $number->truncate()->format(null, ',', ' ', false);
// 12 345,00

$n1 = Decimal::create('12345.671', 3);
$n2 = Decimal::create('11111.111', 3);
$n3 = $n1->add($n2)->mul(-1);
echo $n3; // -23456.782

// fluid interface
$n4 = $n3->pow(2)->sqrt()->mul(-2)->div(2)->abs();

$n1 = Decimal::create('12345.671', 3);
$n1->add(2);
...
echo $n1;
// 12345.671

$n1 = Decimal::create('12345.671', 3);
$n2 = Decimal::create('11111.111', 3);
$n1->gt($n2);        // true
$n1->eq(0);          // false
$n2->le(100);        // false

$n = Decimal::create('12345.671', 3);
echo $n->round(2);   // 12345.67
echo $n->round(1);   // 12345.7
echo $n->truncate(); // 12345
echo $n->ceil(1);    // 12345.6
echo $n->floor();    // 12345

There are exists three internal implementations of this library.

• RtLopez\DecimalBCMath: (default)based on bcmath library
• RtLopez\DecimalFixed: based on scaled integers
• RtLopez\DecimalFloat: based on floats

Only BCMath implementation works correctly in wide spectrum of numbers. All others can fail in many border cases. They was implemented only as proof of concept and you can using it only for your own risk.

The default implementation or precision can be changed by functions:

Decimal::setDefaultImplementation('RtLopez\DecimalBCMath');
Decimal::setDefaultPrecision(6);

This library is distributed under MIT Licence.

Coming soon.

• GMP implementation

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