Quick money (butchering this library for the glory of satan, and CPU cycles)

psalm.xml

@@ -51,13 +51,6 @@
             </errorLevel>
         </InternalMethod>
 
-        <InvalidOperand>
-            <errorLevel type="suppress">
-                <!-- The PhpCalculator is designed to operate with risky/internal math operations -->
-                <file name="src/Calculator/PhpCalculator.php"/>
-            </errorLevel>
-        </InvalidOperand>
-
         <PossiblyUnusedMethod>
             <errorLevel type="suppress">
                 <!-- calculators are not swapped at runtime in our test suite - they are a dead/deprecated concept
@@ -66,14 +59,6 @@
                 <referencedMethod name="Money\Money::registerCalculator"/>
             </errorLevel>
         </PossiblyUnusedMethod>
-
-        <UnusedMethodCall>
-            <errorLevel type="suppress">
-                <!-- the PHP calculator contains runtime assertions, since we're operating under limited
-                     system resources (32bit or 64bit integers) rather than with full fixed point arithmetic -->
-                <file name="src/Calculator/PhpCalculator.php"/>
-            </errorLevel>
-        </UnusedMethodCall>
     </issueHandlers>
 
     <plugins>

spec/NumberSpec.php

@@ -27,12 +27,4 @@ public function it_throws_an_exception_when_number_is_invalid(): void
 
         $this->shouldThrow(InvalidArgumentException::class)->duringInstantiation();
     }
-
-    public function it_creates_a_number_from_float(): void
-    {
-        $number = $this->fromFloat(1.1);
-
-        $number->shouldHaveType(Number::class);
-        $number->__toString()->shouldReturn('1.1');
-    }
 }

src/Calculator.php

@@ -4,6 +4,8 @@
 
 namespace Money;
 
+use Money\Exception\InvalidArgumentException;
+
 /**
  * Money calculations abstracted away from the Money value object.
  *
@@ -70,6 +72,8 @@ public static function multiply(string $amount, string $multiplier): string;
      *
      * @psalm-return numeric-string
      *
+     * @throws InvalidArgumentException when $divisor is zero.
+     *
      * @psalm-pure
      */
     public static function divide(string $amount, string $divisor): string;
@@ -140,9 +144,9 @@ public static function share(string $amount, string $ratio, string $total): stri
      *
      * @psalm-return numeric-string
      *
-     * @psalm-pure
+     * @throws InvalidArgumentException when $divisor is zero.
      *
-     * @TODO what to do with $divisor == '0'?
+     * @psalm-pure
      */
     public static function mod(string $amount, string $divisor): string;
 }

src/Calculator/BcMathCalculator.php

@@ -4,8 +4,9 @@
 
 namespace Money\Calculator;
 
-use InvalidArgumentException;
+use InvalidArgumentException as CoreInvalidArgumentException;
 use Money\Calculator;
+use Money\Exception\InvalidArgumentException;
 use Money\Money;
 use Money\Number;
 
@@ -48,6 +49,10 @@ public static function multiply(string $amount, string $multiplier): string
     /** @psalm-pure */
     public static function divide(string $amount, string $divisor): string
     {
+        if (bccomp($divisor, '0', self::SCALE) === 0) {
+            throw InvalidArgumentException::divisionByZero();
+        }
+
         return bcdiv($amount, $divisor, self::SCALE);
     }
 
@@ -176,7 +181,7 @@ public static function round(string $number, int $roundingMode): string
             );
         }
 
-        throw new InvalidArgumentException('Unknown rounding mode');
+        throw new CoreInvalidArgumentException('Unknown rounding mode');
     }
 
     /**
@@ -206,7 +211,10 @@ public static function share(string $amount, string $ratio, string $total): stri
     /** @psalm-pure */
     public static function mod(string $amount, string $divisor): string
     {
-        // @TODO: null check needed because `bcmod(_, 0)` fails - should the check be kept in here?
+        if (bccomp($divisor, '0') === 0) {
+            throw InvalidArgumentException::moduloByZero();
+        }
+
         return bcmod($amount, $divisor) ?? '0';
     }
 }

src/Calculator/GmpCalculator.php

@@ -4,8 +4,9 @@
 
 namespace Money\Calculator;
 
-use InvalidArgumentException;
+use InvalidArgumentException as CoreInvalidArgumentException;
 use Money\Calculator;
+use Money\Exception\InvalidArgumentException;
 use Money\Money;
 use Money\Number;
 
@@ -27,7 +28,13 @@
 use const GMP_ROUND_MINUSINF;
 use const STR_PAD_LEFT;
 
-/** @psalm-immutable */
+/**
+ * @psalm-immutable
+ *
+ * Important: the {@see GmpCalculator} is not optimized for decimal operations, as GMP
+ *            is designed to operate on large integers. Consider using this only if your
+ *            system does not have `ext-bcmath` installed.
+ */
 final class GmpCalculator implements Calculator
 {
     private const SCALE = 14;
@@ -107,6 +114,10 @@ public static function multiply(string $amount, string $multiplier): string
     /** @psalm-pure */
     public static function divide(string $amount, string $divisor): string
     {
+        if (self::compare($divisor, '0') === 0) {
+            throw InvalidArgumentException::moduloByZero();
+        }
+
         $divisor = Number::fromString($divisor);
 
         if ($divisor->isDecimal()) {
@@ -267,7 +278,7 @@ public static function round(string $number, int $roundingMode): string
             );
         }
 
-        throw new InvalidArgumentException('Unknown rounding mode');
+        throw new CoreInvalidArgumentException('Unknown rounding mode');
     }
 
     /**
@@ -296,6 +307,10 @@ public static function share(string $amount, string $ratio, string $total): stri
     /** @psalm-pure */
     public static function mod(string $amount, string $divisor): string
     {
+        if (self::compare($divisor, '0') === 0) {
+            throw InvalidArgumentException::moduloByZero();
+        }
+
         // gmp_mod() only calculates non-negative integers, so we use absolutes
         $remainder = gmp_mod(self::absolute($amount), self::absolute($divisor));