Use well-named constants to help out your future self

src/Converter/Time/GenericTimeConverter.php

@@ -32,6 +32,22 @@ use const STR_PAD_LEFT;
  */
 class GenericTimeConverter implements TimeConverterInterface
 {
+    /**
+     * The number of 100-nanosecond intervals from the Gregorian calendar epoch
+     * to the Unix epoch.
+     */
+    private const GREGORIAN_TO_UNIX_INTERVALS = '122192928000000000';
+
+    /**
+     * The number of 100-nanosecond intervals in one second.
+     */
+    private const SECOND_INTERVALS = '10000000';
+
+    /**
+     * The number of 100-nanosecond intervals in one microsecond.
+     */
+    private const MICROSECOND_INTERVALS = '10';
+
     /**
      * @var CalculatorInterface
      */
@@ -50,21 +66,28 @@ class GenericTimeConverter implements TimeConverterInterface
     {
         $timestamp = new Time($seconds, $microSeconds);
 
+        // Convert the seconds into a count of 100-nanosecond intervals.
         $sec = $this->calculator->multiply(
             $timestamp->getSeconds(),
-            new IntegerObject('10000000')
+            new IntegerObject(self::SECOND_INTERVALS)
         );
 
+        // Convert the microseconds into a count of 100-nanosecond intervals.
         $usec = $this->calculator->multiply(
             $timestamp->getMicroSeconds(),
-            new IntegerObject('10')
+            new IntegerObject(self::MICROSECOND_INTERVALS)
         );
 
+        // Combine the seconds and microseconds intervals and add the count of
+        // 100-nanosecond intervals from the Gregorian calendar epoch to the
+        // Unix epoch. This gives us the correct count of 100-nanosecond
+        // intervals since the Gregorian calendar epoch for the given seconds
+        // and microseconds.
         /** @var IntegerObject $uuidTime */
         $uuidTime = $this->calculator->add(
             $sec,
             $usec,
-            new IntegerObject('122192928000000000')
+            new IntegerObject(self::GREGORIAN_TO_UNIX_INTERVALS)
         );
 
         $uuidTimeHex = str_pad(
@@ -84,19 +107,20 @@ class GenericTimeConverter implements TimeConverterInterface
     public function convertTime(Hexadecimal $uuidTimestamp): Time
     {
         // From the total, subtract the number of 100-nanosecond intervals from
-        // the UUID epoch (Gregorian calendar date) to the Unix epoch. This
-        // gives us the number of 100-nanosecond intervals from the Unix epoch,
-        // which also includes the microtime.
+        // the Gregorian calendar epoch to the Unix epoch. This gives us the
+        // number of 100-nanosecond intervals from the Unix epoch, which also
+        // includes the microtime.
         $epochNanoseconds = $this->calculator->subtract(
             $this->calculator->toIntegerValue($uuidTimestamp),
-            new IntegerObject('122192928000000000')
+            new IntegerObject(self::GREGORIAN_TO_UNIX_INTERVALS)
         );
 
+        // Convert the 100-nanosecond intervals into seconds and microseconds.
         $unixTimestamp = $this->calculator->divide(
             RoundingMode::HALF_UP,
             6,
             $epochNanoseconds,
-            new IntegerObject('10000000')
+            new IntegerObject(self::SECOND_INTERVALS)
         );
 
         $split = explode('.', (string) $unixTimestamp, 2);

src/Converter/Time/PhpTimeConverter.php

@@ -40,6 +40,22 @@ use const STR_PAD_RIGHT;
  */
 class PhpTimeConverter implements TimeConverterInterface
 {
+    /**
+     * The number of 100-nanosecond intervals from the Gregorian calendar epoch
+     * to the Unix epoch.
+     */
+    private const GREGORIAN_TO_UNIX_INTERVALS = 0x01b21dd213814000;
+
+    /**
+     * The number of 100-nanosecond intervals in one second.
+     */
+    private const SECOND_INTERVALS = 10000000;
+
+    /**
+     * The number of 100-nanosecond intervals in one microsecond.
+     */
+    private const MICROSECOND_INTERVALS = 10;
+
     /**
      * @var CalculatorInterface
      */
@@ -81,15 +97,11 @@ class PhpTimeConverter implements TimeConverterInterface
         $seconds = new IntegerObject($seconds);
         $microSeconds = new IntegerObject($microSeconds);
 
-        // 0x01b21dd213814000 is the number of 100-nanosecond intervals between the
-        // UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00.
-        // - A nanosecond is 1/1,000,000,000 of a second.
-        // - A nanosecond is 1/1,000 of a microsecond.
-        // - There are 10,000,000 100-nanosecond intervals within 1 second.
-        // - There are 10 100-nanosecond intervals within a microsecond.
-        $uuidTime = ((int) $seconds->toString() * 10000000)
-            + ((int) $microSeconds->toString() * 10)
-            + 0x01b21dd213814000;
+        // Calculate the count of 100-nanosecond intervals since the Gregorian
+        // calendar epoch for the given seconds and microseconds.
+        $uuidTime = ((int) $seconds->toString() * self::SECOND_INTERVALS)
+            + ((int) $microSeconds->toString() * self::MICROSECOND_INTERVALS)
+            + self::GREGORIAN_TO_UNIX_INTERVALS;
 
         // Check to see whether we've overflowed the max/min integer size.
         // If so, we will default to a different time converter.
@@ -111,8 +123,10 @@ class PhpTimeConverter implements TimeConverterInterface
     {
         $timestamp = $this->calculator->toIntegerValue($uuidTimestamp);
 
+        // Convert the 100-nanosecond intervals into seconds and microseconds.
         $splitTime = $this->splitTime(
-            ((int) $timestamp->toString() - 0x01b21dd213814000) / 10000000
+            ((int) $timestamp->toString() - self::GREGORIAN_TO_UNIX_INTERVALS)
+            / self::SECOND_INTERVALS
         );
 
         if (count($splitTime) === 0) {