Lib Money
, (*1)
Overview
Symfony2 Bundle wrapping common Money and Currency related needs such as integer-based math, currency codes, and money conversion., (*2)
Installation
Add the package to your composer.json file:, (*3)
{
"repositories": [
{
"type": "vcs",
"url": "https://github.com/matmar10/lib-money"
}
],
"require": {
"matmar10/lib-money": "dev-master"
}
}
Creating Objects
Currencies are identified by a currency code and have a calculation and display precision:, (*4)
$eur = new Currency('EUR', 2, 2);
$euros = new Money($eur);
$euros->setAmountFloat(1.99);
Basic Math
The Money object wraps all basic math functions using underlying integer math
to avoid the (problems with floating point math)[http://stackoverflow.com/questions/3730019/why-not-use-double-or-float-to-represent-currency]., (*5)
All amounts are stored as integer values internally using
the calculation precision as the scale., (*6)
// must use a valid iso4217 currency code
// with the exception of BTC for Bitcoin, as specified in the override configuration
$usd = new Currency('USD', 5, 2);
$usdAmount1 = new Money($usd);
$usdAmount1->setAmountFloat(1.2345);
$usdAmount2 = new Money($usd);
$usdAmount2->setAmountFloat(1.2345);
$usdAmount1->isEqual($usdAmount2); // true
$resultAmount1 = $usdAmount1->add($usdAmount2);
echo $resultAmount1->getAmountDisplay(); // 2.47
$resultAmount2 = $usdAmount1->subtract($usdAmount2);
echo $resultAmount2->getAmountFloat(); // 0
$resultAmount3 = $usdAmount1->multiply(3);
echo $resultAmount3->getAmountFloat(); // 3.7035
echo $resultAmount3->getAmountDisplay(); // 3.70
$resultAmount4 = $usdAmount1->divide(2);
echo $resultAmount3->getAmountFloat(); // 0.61725
echo $resultAmount3->getAmountDisplay(); // 0.62
Dealing with Fractional Cents
How do you divide $10 evenly amongst three people?
In reality, you can't divide fractional cents., (*7)
Really, you want to end up with three equal-ish shares:, (*8)
$eurAmount = new Money(new Currency('EUR', 2, 2));
$eurAmount->setAmountFloat(10);
// split the 10 euros into three equal parts using euro cents as the smallest unit
$shares = $eurAmount->allocate(array(1, 1, 1), 2);
$shares[0]->getAmountFloat(); // 3.34
$shares[1]->getAmountFloat(); // 3.33
$shares[2]->getAmountFloat(); // 3.33
Converting Between Currencies
Use the CurrencyPair object to convert between disparate currencies using an exchange rate:, (*9)
Note that the rate works bi-directionally:, (*10)
$gbp = new Currency('GBP', 2, 2);
$usd = new Currency('USD', 2, 2);
$gbpAmount = new Money($gbp);
$gbpAmount->setAmountFloat(10);
// 1 GBP = 1.5 USD
$gbpToUsd = new CurrencyPair($gbp, $usd, 1.5);
$usdAmount = $gbpToUsd->convert($gbpAmount);
echo $usdAmount->getDisplay(); // 15.00
$gbpAmount2 = $gbpToUsd->convert($usdAmount);
echo $gbpAmount2->getDisplay(); // 10.00
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