Utils.php
No OneTemporary
Actions

Authored By

Unknown

Size

1 KB

Referenced Files

None

Subscribers

None

Utils.php
View Options

	<?php

	namespace App;

	use Ramsey\Uuid\Uuid;

	/**
	* Small utility functions for App.
	*/
	class Utils
	{
	/**
	* Provide all unique combinations of elements in $input, with order and duplicates irrelevant.
	*
	* @param array $input The input array of elements.
	*
	* @return array[]
	*/
	public static function powerSet(array $input): array
	{
	$output = [];

	for ($x = 0; $x < count($input); $x++) {
	self::combine($input, $x + 1, 0, [], 0, $output);
	}

	return $output;
	}

	/**
	* Returns a UUID in the form of an integer.
	*
	* @return integer
	*/
	public static function uuidInt(): int
	{
	$hex = Uuid::uuid4();
	$bin = pack('h*', str_replace('-', '', $hex));
	$ids = unpack('L', $bin);
	$id = array_shift($ids);

	return $id;
	}

	/**
	* Returns a UUID in the form of a string.
	*
	* @return string
	*/
	public static function uuidStr(): string
	{
	return (string) Uuid::uuid4();
	}

	private static function combine($input, $r, $index, $data, $i, &$output): void
	{
	$n = count($input);

	// Current cobination is ready
	if ($index == $r) {
	$output[] = array_slice($data, 0, $r);
	return;
	}

	// When no more elements are there to put in data[]
	if ($i >= $n) {
	return;
	}

	// current is included, put next at next location
	$data[$index] = $input[$i];
	self::combine($input, $r, $index + 1, $data, $i + 1, $output);

	// current is excluded, replace it with next (Note that i+1
	// is passed, but index is not changed)
	self::combine($input, $r, $index, $data, $i + 1, $output);
	}
	}