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<?php |
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namespace Didatus\RandomString; |
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/** |
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* Class RandomString |
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* @package Didatus\RandomString |
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*/ |
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class RandomString { |
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/** |
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* contains the list of characters to be used for random string generation |
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* @var string |
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*/ |
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private $character_pool = ''; |
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/** |
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* contains the list of characters to be excluded from random string generation |
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* @var string |
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*/ |
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private $except_characters = ''; |
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private $calculated_character_pool = ''; |
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/** |
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* defines wether a character is unique in a random string or not |
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* @var bool |
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*/ |
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private $unique_characters = false; |
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/** |
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* RandomString constructor. |
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* @param string $character_pool |
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* @param string $except_characters |
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* @param bool $unique_characters |
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*/ |
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public function __construct( |
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string $character_pool = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', |
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string $except_characters = '', |
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bool $unique_characters = false |
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) { |
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$this->character_pool = $character_pool; |
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$this->except_characters = $except_characters; |
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$this->unique_characters = $unique_characters; |
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} |
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/** |
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* generates one random string of $length and returns it |
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* @param int $length |
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* @return string |
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* @throws CharacterPoolTooSmallException |
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*/ |
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public function getString(int $length = 10):string |
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{ |
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$this->checkInputLength($length); |
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$string_length = 0; |
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$string = ''; |
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while ($string_length < $length) |
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{ |
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$character = $this->getRandomCharacter(); |
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if ($this->unique_characters && $this->containsCharacter($string, $character)) { |
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continue; |
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} |
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$string .= $character; |
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$string_length = strlen($string); |
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} |
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return $string; |
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} |
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/** |
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* generates a list of random strings of $length and returns it |
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* @param $length |
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* @param $count |
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* @return array |
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*/ |
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public function getListOfString(int $length, int $count):array |
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{ |
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$list_count = 0; |
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for ($strings = []; $list_count < $count;) |
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{ |
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$strings[] = $this->getString($length); |
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$list_count = count($strings); |
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} |
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return $strings; |
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} |
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/** |
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* provides a random character |
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* @return string |
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*/ |
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private function getRandomCharacter():string |
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{ |
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return $this->getCharacterPool()[rand(0, strlen($this->getCharacterPool()) - 1)]; |
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} |
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/** |
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* generates the character pool without character exceptions |
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* @return string |
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*/ |
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private function getCharacterPool():string |
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{ |
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if (empty($this->calculated_character_pool)) { |
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$this->calculated_character_pool = implode( |
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"", |
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array_diff(str_split($this->character_pool), str_split($this->except_characters)) |
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); |
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} |
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return $this->calculated_character_pool; |
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} |
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/** |
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* checks if the given string contains given character |
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* @param $string |
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* @param $character |
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* @return bool |
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*/ |
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private function containsCharacter(string $string, string $character):bool |
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{ |
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if (strpos($string, $character) !== false) { |
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return true; |
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} |
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return false; |
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} |
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/** |
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* checks wether the character pool is big enough for unique character string with given length or not |
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* @param int $length |
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* @throws CharacterPoolTooSmallException |
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*/ |
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private function checkInputLength(int $length):void |
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{ |
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$character_pool_size = strlen($this->getCharacterPool()); |
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if ($this->unique_characters && $length > $character_pool_size) { |
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throw new CharacterPoolTooSmallException( |
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"Character pool of length " . $character_pool_size . |
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" is too small to generate a random unique character string with length " . $length . "!" |
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); |
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} |
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} |
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} |
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