CHIEFSOFT\ameye
96 lines
2.9 KiB
PHP
96 lines
2.9 KiB
PHP
<?php
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/**
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* @file classes/doi/DoiGenerator.php
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*
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* Copyright (c) 2014-2022 Simon Fraser University
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* Copyright (c) 2000-2022 John Willinsky
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* Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
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*
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* @class DoiGenerator
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*
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* @brief A utility class for generating DOI suffixes using the Cool DOIs pattern, which generates opaque, but easy to read suffixes.
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*
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* @see https://blog.datacite.org/cool-dois/
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*/
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namespace PKP\doi;
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use Dflydev\Base32\Crockford\Crockford;
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class DoiGenerator
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{
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// 32 by the factor of 6
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protected const UPPER_LIMIT = 1073741823;
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/**
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* Constructs a DOI with an 8-character suffix, using a Crockford Base 32 algorithm
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* to generate the suffix.
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*
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*/
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public static function encodeSuffix(): string
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{
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$number = random_int(1, self::UPPER_LIMIT);
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return self::base32EncodeSuffix($number);
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}
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/**
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* Returns the decoded int used to generate the suffix after validating the two-digit checksum
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*
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* @return int|null Returns null if checksum is invalid
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*/
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public static function decodeSuffix(string $suffix): ?int
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{
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$suffix = strtoupper($suffix);
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$suffixParts = str_split($suffix, 6);
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$encodedString = $suffixParts[0];
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$checksum = $suffixParts[1];
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$decodedSuffix = Crockford::decode($encodedString);
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$isSuffixValid = self::verifySuffixChecksum($decodedSuffix, $checksum);
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return $isSuffixValid ? $decodedSuffix : null;
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}
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/**
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* Encodes suffix as 8-digit base32 encoded string where the final two numbers are a checksum.
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*
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* E.g. DDDDDDYY where 'D' is a base32 encoded character and 'YY' is the checksum.
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*
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* @param int $number A random number between 1 and 1073741823 (UPPER_LIMIT). Used as seed for encoding suffix.
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*/
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protected static function base32EncodeSuffix(int $number): string
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{
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// Initial base32 encoded string (up to 6 characters max)
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$encodedNumber = strtolower(Crockford::encode($number));
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// Add checksum at end of string, calculated as modulo 97-10 (ISO 7064)
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$remainder = self::calculateChecksum($number);
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$payload = $encodedNumber . sprintf('%02d', $remainder);
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return str_pad($payload, 8, '0', STR_PAD_LEFT);
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}
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/**
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* Verifies the provided checksum was generated from the number provided.
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*
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* @param int $number The integer decoded form the base 32 suffix. Original number used to generate suffix.
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* @param int $checksum The two-digit checksum (last two digits of suffix)
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*/
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protected static function verifySuffixChecksum(int $number, int $checksum): bool
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{
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return $checksum === self::calculateChecksum($number);
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}
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/**
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* Checksum calculated as modulo 97-10 (ISO 7064).
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*/
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protected static function calculateChecksum(int $number): int
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{
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return 98 - (($number * 100) % 97);
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}
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}
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