Adds percentage increase and decrease calculation methods

elliotjreed · Dec 3, 2023 · 58bf0c2 · 58bf0c2
1 parent 03ca7a7
commit 58bf0c2
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Showing 5 changed files with 406 additions and 2 deletions.
diff --git a/src/ElliotJReed/Maths/Number.php b/src/ElliotJReed/Maths/Number.php
@@ -164,4 +164,44 @@ public function raiseToPowerReduceByModulus(
 
         return $this;
     }
+
+    /**
+     * @param \ElliotJReed\Maths\Number|int|float|string $percent the percentage to increase the "base" number by
+     *
+     * @return $this
+     */
+    public function increaseByPercentage(self | int | float | string $percent): self
+    {
+        $percentAsString = $this->castNumberToString($percent);
+
+        $increase = \bcmul(
+            $this->number,
+            \bcdiv($percentAsString, '100', $this->precision),
+            $this->precision
+        );
+
+        $this->number = \bcadd($this->number, $increase, $this->precision);
+
+        return $this;
+    }
+
+    /**
+     * @param \ElliotJReed\Maths\Number|int|float|string $percent the percentage to decrease the "base" number by
+     *
+     * @return $this
+     */
+    public function decreaseByPercentage(self | int | float | string $percent): self
+    {
+        $percentAsString = $this->castNumberToString($percent);
+
+        $increase = \bcmul(
+            $this->number,
+            \bcmul(\bcdiv($percentAsString, '100', $this->precision), '-1', $this->precision),
+            $this->precision
+        );
+
+        $this->number = \bcadd($this->number, $increase, $this->precision);
+
+        return $this;
+    }
 }
diff --git a/src/ElliotJReed/Maths/NumberFormat.php b/src/ElliotJReed/Maths/NumberFormat.php
@@ -12,9 +12,9 @@ abstract class NumberFormat
 
     /**
      * @param \ElliotJReed\Maths\Number|int|float|string $number    (Optional) The "base" number. Default: 0
-     * @param int                                        $precision (Optional) The number of digits after the decimal place in the result. Default: 64
+     * @param int                                        $precision (Optional) The number of digits after the decimal place in the result. Default: 256
      */
-    public function __construct(self | int | float | string $number = 0, protected readonly int $precision = 64)
+    public function __construct(self | int | float | string $number = 0, protected readonly int $precision = 256)
     {
         $this->number = $this->castNumberToString($number);
     }

diff --git a/src/ElliotJReed/Maths/NumberImmutable.php b/src/ElliotJReed/Maths/NumberImmutable.php
@@ -166,4 +166,44 @@ public function raiseToPowerReduceByModulus(
 
         return new self($newNumber, $this->precision);
     }
+
+    /**
+     * @param \ElliotJReed\Maths\Number|int|float|string $percent the percentage to increase the "base" number by
+     *
+     * @return $this Returns a new instance of \ElliotJReed\Maths\Number
+     */
+    public function increaseByPercentage(self | int | float | string $percent): self
+    {
+        $percentAsString = $this->castNumberToString($percent);
+
+        $increase = \bcmul(
+            $this->number,
+            \bcdiv($percentAsString, '100', $this->precision),
+            $this->precision
+        );
+
+        $newNumber = \bcadd($this->number, $increase, $this->precision);
+
+        return new self($newNumber, $this->precision);
+    }
+
+    /**
+     * @param \ElliotJReed\Maths\Number|int|float|string $percent the percentage to decrease the "base" number by
+     *
+     * @return $this Returns a new instance of \ElliotJReed\Maths\Number
+     */
+    public function decreaseByPercentage(self | int | float | string $percent): self
+    {
+        $percentAsString = $this->castNumberToString($percent);
+
+        $increase = \bcmul(
+            $this->number,
+            \bcmul(\bcdiv($percentAsString, '100', $this->precision), '-1', $this->precision),
+            $this->precision
+        );
+
+        $newNumber = \bcadd($this->number, $increase, $this->precision);
+
+        return new self($newNumber, $this->precision);
+    }
 }
diff --git a/tests/ElliotJReed/Maths/NumberImmutableTest.php b/tests/ElliotJReed/Maths/NumberImmutableTest.php
@@ -1316,4 +1316,196 @@ public function testItThrowsExceptionWhenDecimalPlacesArgumentIsLessThanZeroWhen
 
         $number->roundToDecimalPlaces(-2);
     }
+
+    public function testItIncreasesBaseNumberByPercentageWhenNumberIsAnInteger(): void
+    {
+        $number = new NumberImmutable(100);
+        $newNumber = $number->increaseByPercentage(10);
+
+        $this->assertSame('110', $newNumber->asString());
+        $this->assertSame(110.0, $newNumber->asFloat());
+        $this->assertSame(110, $newNumber->asInteger());
+        $this->assertSame(110, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100', $number->asString());
+        $this->assertSame(100.0, $number->asFloat());
+        $this->assertSame(100, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItIncreasesBaseNumberByPercentageWhenNumberIsAFloat(): void
+    {
+        $number = new NumberImmutable(100.50);
+        $newNumber = $number->increaseByPercentage(10.125);
+
+        $this->assertSame('110.675625', $newNumber->asString());
+        $this->assertSame(110.675625, $newNumber->asFloat());
+        $this->assertSame(111, $newNumber->asInteger());
+        $this->assertSame(111, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100.5', $number->asString());
+        $this->assertSame(100.5, $number->asFloat());
+        $this->assertSame(101, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItIncreasesBaseNumberByPercentageWhenNumberIsAString(): void
+    {
+        $number = new NumberImmutable('100.50');
+        $newNumber = $number->increaseByPercentage('10.125');
+
+        $this->assertSame('110.675625', $newNumber->asString());
+        $this->assertSame(110.675625, $newNumber->asFloat());
+        $this->assertSame(111, $newNumber->asInteger());
+        $this->assertSame(111, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100.5', $number->asString());
+        $this->assertSame(100.5, $number->asFloat());
+        $this->assertSame(101, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItIncreasesBaseNumberByNegativePercentageWhenNumberIsAnInteger(): void
+    {
+        $number = new NumberImmutable(100);
+        $newNumber = $number->increaseByPercentage(-10);
+
+        $this->assertSame('90', $newNumber->asString());
+        $this->assertSame(90.0, $newNumber->asFloat());
+        $this->assertSame(90, $newNumber->asInteger());
+        $this->assertSame(90, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100', $number->asString());
+        $this->assertSame(100.0, $number->asFloat());
+        $this->assertSame(100, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItIncreasesBaseNumberByNegativePercentageWhenNumberIsAFloat(): void
+    {
+        $number = new NumberImmutable(-100.25);
+        $newNumber = $number->increaseByPercentage(-10.55);
+
+        $this->assertSame('-89.673625', $newNumber->asString());
+        $this->assertSame(-89.673625, $newNumber->asFloat());
+        $this->assertSame(-90, $newNumber->asInteger());
+        $this->assertSame(-90, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('-100.25', $number->asString());
+        $this->assertSame(-100.25, $number->asFloat());
+        $this->assertSame(-100, $number->asInteger());
+        $this->assertSame(-100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItIncreasesBaseNumberByNegativePercentageWhenNumberIsAString(): void
+    {
+        $number = new NumberImmutable('100.33');
+        $newNumber = $number->increaseByPercentage('-10.66');
+
+        $this->assertSame('89.634822', $newNumber->asString());
+        $this->assertSame(89.634822, $newNumber->asFloat());
+        $this->assertSame(90, $newNumber->asInteger());
+        $this->assertSame(90, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100.33', $number->asString());
+        $this->assertSame(100.33, $number->asFloat());
+        $this->assertSame(100, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItDecreasesBaseNumberByPercentageWhenNumberIsAnInteger(): void
+    {
+        $number = new NumberImmutable(100);
+        $newNumber = $number->decreaseByPercentage(10);
+
+        $this->assertSame('90', $newNumber->asString());
+        $this->assertSame(90.0, $newNumber->asFloat());
+        $this->assertSame(90, $newNumber->asInteger());
+        $this->assertSame(90, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100', $number->asString());
+        $this->assertSame(100.0, $number->asFloat());
+        $this->assertSame(100, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItDecreasesBaseNumberByPercentageWhenNumberIsAFloat(): void
+    {
+        $number = new NumberImmutable(10.99);
+        $newNumber = $number->decreaseByPercentage(5.123);
+
+        $this->assertSame('10.4269823', $newNumber->asString());
+        $this->assertSame(10.4269823, $newNumber->asFloat());
+        $this->assertSame(10, $newNumber->asInteger());
+        $this->assertSame(10, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('10.99', $number->asString());
+        $this->assertSame(10.99, $number->asFloat());
+        $this->assertSame(11, $number->asInteger());
+        $this->assertSame(11, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItDecreasesBaseNumberByPercentageWhenNumberIsAString(): void
+    {
+        $number = new NumberImmutable('10.99');
+        $newNumber = $number->decreaseByPercentage('5.123');
+
+        $this->assertSame('10.4269823', $newNumber->asString());
+        $this->assertSame(10.4269823, $newNumber->asFloat());
+        $this->assertSame(10, $newNumber->asInteger());
+        $this->assertSame(10, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('10.99', $number->asString());
+        $this->assertSame(10.99, $number->asFloat());
+        $this->assertSame(11, $number->asInteger());
+        $this->assertSame(11, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItDecreasesBaseNumberByNegativePercentageWhenNumberIsAnInteger(): void
+    {
+        $number = new NumberImmutable(100);
+        $newNumber = $number->decreaseByPercentage(-10);
+
+        $this->assertSame('110', $newNumber->asString());
+        $this->assertSame(110.0, $newNumber->asFloat());
+        $this->assertSame(110, $newNumber->asInteger());
+        $this->assertSame(110, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('100', $number->asString());
+        $this->assertSame(100.0, $number->asFloat());
+        $this->assertSame(100, $number->asInteger());
+        $this->assertSame(100, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItDecreasesBaseNumberByNegativePercentageWhenNumberIsAFloat(): void
+    {
+        $number = new NumberImmutable(25.5);
+        $newNumber = $number->decreaseByPercentage(15.25);
+
+        $this->assertSame('21.61125', $newNumber->asString());
+        $this->assertSame(21.61125, $newNumber->asFloat());
+        $this->assertSame(22, $newNumber->asInteger());
+        $this->assertSame(22, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('25.5', $number->asString());
+        $this->assertSame(25.5, $number->asFloat());
+        $this->assertSame(26, $number->asInteger());
+        $this->assertSame(25, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
+
+    public function testItDecreasesBaseNumberByNegativePercentageWhenNumberIsAString(): void
+    {
+        $number = new NumberImmutable('25.5');
+        $newNumber = $number->decreaseByPercentage('15.25');
+
+        $this->assertSame('21.61125', $newNumber->asString());
+        $this->assertSame(21.61125, $newNumber->asFloat());
+        $this->assertSame(22, $newNumber->asInteger());
+        $this->assertSame(22, $newNumber->asInteger(\PHP_ROUND_HALF_DOWN));
+
+        $this->assertSame('25.5', $number->asString());
+        $this->assertSame(25.5, $number->asFloat());
+        $this->assertSame(26, $number->asInteger());
+        $this->assertSame(25, $number->asInteger(\PHP_ROUND_HALF_DOWN));
+    }
 }