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vendor/ramsey/uuid/src/Generator/CombGenerator.php

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+<?php
+
+/**
+ * This file is part of the ramsey/uuid library
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @copyright Copyright (c) Ben Ramsey <ben@benramsey.com>
+ * @license http://opensource.org/licenses/MIT MIT
+ */
+
+declare(strict_types=1);
+
+namespace Ramsey\Uuid\Generator;
+
+use Ramsey\Uuid\Converter\NumberConverterInterface;
+use Ramsey\Uuid\Exception\InvalidArgumentException;
+
+use function bin2hex;
+use function explode;
+use function hex2bin;
+use function microtime;
+use function str_pad;
+use function substr;
+
+use const STR_PAD_LEFT;
+
+/**
+ * CombGenerator generates COMBs (combined UUID/timestamp)
+ *
+ * The CombGenerator, when used with the StringCodec (and, by proxy, the
+ * TimestampLastCombCodec) or the TimestampFirstCombCodec, combines the current
+ * timestamp with a UUID (hence the name "COMB"). The timestamp either appears
+ * as the first or last 48 bits of the COMB, depending on the codec used.
+ *
+ * By default, COMBs will have the timestamp set as the last 48 bits of the
+ * identifier.
+ *
+ * ``` php
+ * $factory = new UuidFactory();
+ *
+ * $factory->setRandomGenerator(new CombGenerator(
+ *     $factory->getRandomGenerator(),
+ *     $factory->getNumberConverter()
+ * ));
+ *
+ * $comb = $factory->uuid4();
+ * ```
+ *
+ * To generate a COMB with the timestamp as the first 48 bits, set the
+ * TimestampFirstCombCodec as the codec.
+ *
+ * ``` php
+ * $factory->setCodec(new TimestampFirstCombCodec($factory->getUuidBuilder()));
+ * ```
+ *
+ * @link https://www.informit.com/articles/printerfriendly/25862 The Cost of GUIDs as Primary Keys
+ */
+class CombGenerator implements RandomGeneratorInterface
+{
+    public const TIMESTAMP_BYTES = 6;
+
+    public function __construct(
+        private RandomGeneratorInterface $generator,
+        private NumberConverterInterface $numberConverter
+    ) {
+    }
+
+    /**
+     * @throws InvalidArgumentException if $length is not a positive integer
+     *     greater than or equal to CombGenerator::TIMESTAMP_BYTES
+     *
+     * @inheritDoc
+     */
+    public function generate(int $length): string
+    {
+        if ($length < self::TIMESTAMP_BYTES) {
+            throw new InvalidArgumentException(
+                'Length must be a positive integer greater than or equal to ' . self::TIMESTAMP_BYTES
+            );
+        }
+
+        $hash = '';
+        if (self::TIMESTAMP_BYTES > 0 && $length > self::TIMESTAMP_BYTES) {
+            $hash = $this->generator->generate($length - self::TIMESTAMP_BYTES);
+        }
+
+        $lsbTime = str_pad(
+            $this->numberConverter->toHex($this->timestamp()),
+            self::TIMESTAMP_BYTES * 2,
+            '0',
+            STR_PAD_LEFT
+        );
+
+        return (string) hex2bin(
+            str_pad(
+                bin2hex($hash),
+                $length - self::TIMESTAMP_BYTES,
+                '0'
+            )
+            . $lsbTime
+        );
+    }
+
+    /**
+     * Returns current timestamp a string integer, precise to 0.00001 seconds
+     */
+    private function timestamp(): string
+    {
+        $time = explode(' ', microtime(false));
+
+        return $time[1] . substr($time[0], 2, 5);
+    }
+}