<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\String;

use Symfony\Component\String\Exception\ExceptionInterface;
use Symfony\Component\String\Exception\InvalidArgumentException;
use Symfony\Component\String\Exception\RuntimeException;

/**
 * Represents a binary-safe string of bytes.
 *
 * @author Nicolas Grekas <p@tchwork.com>
 * @author Hugo Hamon <hugohamon@neuf.fr>
 *
 * @throws ExceptionInterface
 */
class ByteString extends AbstractString
{
    private const ALPHABET_ALPHANUMERIC = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';

    public function __construct(string $string = '')
    {
        $this->string = $string;
    }

    /*
     * The following method was derived from code of the Hack Standard Library (v4.40 - 2020-05-03)
     *
     * https://github.com/hhvm/hsl/blob/80a42c02f036f72a42f0415e80d6b847f4bf62d5/src/random/private.php#L16
     *
     * Code subject to the MIT license (https://github.com/hhvm/hsl/blob/master/LICENSE).
     *
     * Copyright (c) 2004-2020, Facebook, Inc. (https://www.facebook.com/)
     */

    public static function fromRandom(int $length = 16, string $alphabet = null): self
    {
        if ($length <= 0) {
            throw new InvalidArgumentException(sprintf('A strictly positive length is expected, "%d" given.', $length));
        }

        $alphabet = $alphabet ?? self::ALPHABET_ALPHANUMERIC;
        $alphabetSize = \strlen($alphabet);
        $bits = (int) ceil(log($alphabetSize, 2.0));
        if ($bits <= 0 || $bits > 56) {
            throw new InvalidArgumentException('The length of the alphabet must in the [2^1, 2^56] range.');
        }

        $ret = '';
        while ($length > 0) {
            $urandomLength = (int) ceil(2 * $length * $bits / 8.0);
            $data = random_bytes($urandomLength);
            $unpackedData = 0;
            $unpackedBits = 0;
            for ($i = 0; $i < $urandomLength && $length > 0; ++$i) {
                // Unpack 8 bits
                $unpackedData = ($unpackedData << 8) | \ord($data[$i]);
                $unpackedBits += 8;

                // While we have enough bits to select a character from the alphabet, keep
                // consuming the random data
                for (; $unpackedBits >= $bits && $length > 0; $unpackedBits -= $bits) {
                    $index = ($unpackedData & ((1 << $bits) - 1));
                    $unpackedData >>= $bits;
                    // Unfortunately, the alphabet size is not necessarily a power of two.
                    // Worst case, it is 2^k + 1, which means we need (k+1) bits and we
                    // have around a 50% chance of missing as k gets larger
                    if ($index < $alphabetSize) {
                        $ret .= $alphabet[$index];
                        --$length;
                    }
                }
            }
        }

        return new static($ret);
    }

    public function bytesAt(int $offset): array
    {
        $str = $this->string[$offset] ?? '';

        return '' === $str ? [] : [\ord($str)];
    }

    public function append(string ...$suffix): static
    {
        $str = clone $this;
        $str->string .= 1 >= \count($suffix) ? ($suffix[0] ?? '') : implode('', $suffix);

        return $str;
    }

    public function camel(): static
    {
        $str = clone $this;

        $parts = explode(' ', trim(ucwords(preg_replace('/[^a-zA-Z0-9\x7f-\xff]++/', ' ', $this->string))));
        $parts[0] = 1 !== \strlen($parts[0]) && ctype_upper($parts[0]) ? $parts[0] : lcfirst($parts[0]);
        $str->string = implode('', $parts);

        return $str;
    }

    public function chunk(int $length = 1): array
    {
        if (1 > $length) {
            throw new InvalidArgumentException('The chunk length must be greater than zero.');
        }

        if ('' === $this->string) {
            return [];
        }

        $str = clone $this;
        $chunks = [];

        foreach (str_split($this->string, $length) as $chunk) {
            $str->string = $chunk;
            $chunks[] = clone $str;
        }

        return $chunks;
    }

    public function endsWith(string|iterable|AbstractString $suffix): bool
    {
        if ($suffix instanceof AbstractString) {
            $suffix = $suffix->string;
        } elseif (!\is_string($suffix)) {
            return parent::endsWith($suffix);
        }

        return '' !== $suffix && \strlen($this->string) >= \strlen($suffix) && 0 === substr_compare($this->string, $suffix, -\strlen($suffix), null, $this->ignoreCase);
    }

    public function equalsTo(string|iterable|AbstractString $string): bool
    {
        if ($string instanceof AbstractString) {
            $string = $string->string;
        } elseif (!\is_string($string)) {
            return parent::equalsTo($string);
        }

        if ('' !== $string && $this->ignoreCase) {
            return 0 === strcasecmp($string, $this->string);
        }

        return $string === $this->string;
    }

    public function folded(): static
    {
        $str = clone $this;
        $str->string = strtolower($str->string);

        return $str;
    }

    public function indexOf(string|iterable|AbstractString $needle, int $offset = 0): ?int
    {
        if ($needle instanceof AbstractString) {
            $needle = $needle->string;
        } elseif (!\is_string($needle)) {
            return parent::indexOf($needle, $offset);
        }

        if ('' === $needle) {
            return null;
        }

        $i = $this->ignoreCase ? stripos($this->string, $needle, $offset) : strpos($this->string, $needle, $offset);

        return false === $i ? null : $i;
    }

    public function indexOfLast(string|iterable|AbstractString $needle, int $offset = 0): ?int
    {
        if ($needle instanceof AbstractString) {
            $needle = $needle->string;
        } elseif (!\is_string($needle)) {
            return parent::indexOfLast($needle, $offset);
        }

        if ('' === $needle) {
            return null;
        }

        $i = $this->ignoreCase ? strripos($this->string, $needle, $offset) : strrpos($this->string, $needle, $offset);

        return false === $i ? null : $i;
    }

    public function isUtf8(): bool
    {
        return '' === $this->string || preg_match('//u', $this->string);
    }

    public function join(array $strings, string $lastGlue = null): static
    {
        $str = clone $this;

        $tail = null !== $lastGlue && 1 < \count($strings) ? $lastGlue.array_pop($strings) : '';
        $str->string = implode($this->string, $strings).$tail;

        return $str;
    }

    public function length(): int
    {
        return \strlen($this->string);
    }

    public function lower(): static
    {
        $str = clone $this;
        $str->string = strtolower($str->string);

        return $str;
    }

    public function match(string $regexp, int $flags = 0, int $offset = 0): array
    {
        $match = ((\PREG_PATTERN_ORDER | \PREG_SET_ORDER) & $flags) ? 'preg_match_all' : 'preg_match';

        if ($this->ignoreCase) {
            $regexp .= 'i';
        }

        set_error_handler(static function ($t, $m) { throw new InvalidArgumentException($m); });

        try {
            if (false === $match($regexp, $this->string, $matches, $flags | \PREG_UNMATCHED_AS_NULL, $offset)) {
                $lastError = preg_last_error();

                foreach (get_defined_constants(true)['pcre'] as $k => $v) {
                    if ($lastError === $v && '_ERROR' === substr($k, -6)) {
                        throw new RuntimeException('Matching failed with '.$k.'.');
                    }
                }

                throw new RuntimeException('Matching failed with unknown error code.');
            }
        } finally {
            restore_error_handler();
        }

        return $matches;
    }

    public function padBoth(int $length, string $padStr = ' '): static
    {
        $str = clone $this;
        $str->string = str_pad($this->string, $length, $padStr, \STR_PAD_BOTH);

        return $str;
    }

    public function padEnd(int $length, string $padStr = ' '): static
    {
        $str = clone $this;
        $str->string = str_pad($this->string, $length, $padStr, \STR_PAD_RIGHT);

        return $str;
    }

    public function padStart(int $length, string $padStr = ' '): static
    {
        $str = clone $this;
        $str->string = str_pad($this->string, $length, $padStr, \STR_PAD_LEFT);

        return $str;
    }

    public function prepend(string ...$prefix): static
    {
        $str = clone $this;
        $str->string = (1 >= \count($prefix) ? ($prefix[0] ?? '') : implode('', $prefix)).$str->string;

        return $str;
    }

    public function replace(string $from, string $to): static
    {
        $str = clone $this;

        if ('' !== $from) {
            $str->string = $this->ignoreCase ? str_ireplace($from, $to, $this->string) : str_replace($from, $to, $this->string);
        }

        return $str;
    }

    public function replaceMatches(string $fromRegexp, string|callable $to): static
    {
        if ($this->ignoreCase) {
            $fromRegexp .= 'i';
        }

        $replace = \is_array($to) || $to instanceof \Closure ? 'preg_replace_callback' : 'preg_replace';

        set_error_handler(static function ($t, $m) { throw new InvalidArgumentException($m); });

        try {
            if (null === $string = $replace($fromRegexp, $to, $this->string)) {
                $lastError = preg_last_error();

                foreach (get_defined_constants(true)['pcre'] as $k => $v) {
                    if ($lastError === $v && '_ERROR' === substr($k, -6)) {
                        throw new RuntimeException('Matching failed with '.$k.'.');
                    }
                }

                throw new RuntimeException('Matching failed with unknown error code.');
            }
        } finally {
            restore_error_handler();
        }

        $str = clone $this;
        $str->string = $string;

        return $str;
    }

    public function reverse(): static
    {
        $str = clone $this;
        $str->string = strrev($str->string);

        return $str;
    }

    public function slice(int $start = 0, int $length = null): static
    {
        $str = clone $this;
        $str->string = (string) substr($this->string, $start, $length ?? \PHP_INT_MAX);

        return $str;
    }

    public function snake(): static
    {
        $str = $this->camel();
        $str->string = strtolower(preg_replace(['/([A-Z]+)([A-Z][a-z])/', '/([a-z\d])([A-Z])/'], '\1_\2', $str->string));

        return $str;
    }

    public function splice(string $replacement, int $start = 0, int $length = null): static
    {
        $str = clone $this;
        $str->string = substr_replace($this->string, $replacement, $start, $length ?? \PHP_INT_MAX);

        return $str;
    }

    public function split(string $delimiter, int $limit = null, int $flags = null): array
    {
        if (1 > $limit = $limit ?? \PHP_INT_MAX) {
            throw new InvalidArgumentException('Split limit must be a positive integer.');
        }

        if ('' === $delimiter) {
            throw new InvalidArgumentException('Split delimiter is empty.');
        }

        if (null !== $flags) {
            return parent::split($delimiter, $limit, $flags);
        }

        $str = clone $this;
        $chunks = $this->ignoreCase
            ? preg_split('{'.preg_quote($delimiter).'}iD', $this->string, $limit)
            : explode($delimiter, $this->string, $limit);

        foreach ($chunks as &$chunk) {
            $str->string = $chunk;
            $chunk = clone $str;
        }

        return $chunks;
    }

    public function startsWith(string|iterable|AbstractString $prefix): bool
    {
        if ($prefix instanceof AbstractString) {
            $prefix = $prefix->string;
        } elseif (!\is_string($prefix)) {
            return parent::startsWith($prefix);
        }

        return '' !== $prefix && 0 === ($this->ignoreCase ? strncasecmp($this->string, $prefix, \strlen($prefix)) : strncmp($this->string, $prefix, \strlen($prefix)));
    }

    public function title(bool $allWords = false): static
    {
        $str = clone $this;
        $str->string = $allWords ? ucwords($str->string) : ucfirst($str->string);

        return $str;
    }

    public function toUnicodeString(string $fromEncoding = null): UnicodeString
    {
        return new UnicodeString($this->toCodePointString($fromEncoding)->string);
    }

    public function toCodePointString(string $fromEncoding = null): CodePointString
    {
        $u = new CodePointString();

        if (\in_array($fromEncoding, [null, 'utf8', 'utf-8', 'UTF8', 'UTF-8'], true) && preg_match('//u', $this->string)) {
            $u->string = $this->string;

            return $u;
        }

        set_error_handler(static function ($t, $m) { throw new InvalidArgumentException($m); });

        try {
            try {
                $validEncoding = false !== mb_detect_encoding($this->string, $fromEncoding ?? 'Windows-1252', true);
            } catch (InvalidArgumentException $e) {
                if (!\function_exists('iconv')) {
                    throw $e;
                }

                $u->string = iconv($fromEncoding ?? 'Windows-1252', 'UTF-8', $this->string);

                return $u;
            }
        } finally {
            restore_error_handler();
        }

        if (!$validEncoding) {
            throw new InvalidArgumentException(sprintf('Invalid "%s" string.', $fromEncoding ?? 'Windows-1252'));
        }

        $u->string = mb_convert_encoding($this->string, 'UTF-8', $fromEncoding ?? 'Windows-1252');

        return $u;
    }

    public function trim(string $chars = " \t\n\r\0\x0B\x0C"): static
    {
        $str = clone $this;
        $str->string = trim($str->string, $chars);

        return $str;
    }

    public function trimEnd(string $chars = " \t\n\r\0\x0B\x0C"): static
    {
        $str = clone $this;
        $str->string = rtrim($str->string, $chars);

        return $str;
    }

    public function trimStart(string $chars = " \t\n\r\0\x0B\x0C"): static
    {
        $str = clone $this;
        $str->string = ltrim($str->string, $chars);

        return $str;
    }

    public function upper(): static
    {
        $str = clone $this;
        $str->string = strtoupper($str->string);

        return $str;
    }

    public function width(bool $ignoreAnsiDecoration = true): int
    {
        $string = preg_match('//u', $this->string) ? $this->string : preg_replace('/[\x80-\xFF]/', '?', $this->string);

        return (new CodePointString($string))->width($ignoreAnsiDecoration);
    }
}

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• [F] AbstractString.php
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• [F] ByteString.php
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• [F] CHANGELOG.md
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Encryption is a process that transforms data into a secure format, known as ciphertext, which can only be deciphered using a specific decryption key. This means that even if data is intercepted during transmission, it remains unreadable and protected from unauthorized access. Encryption is essential in safeguarding sensitive payment information, such as credit card details and personal data, during online transactions.
Tokenization, on the other hand, involves substituting sensitive data with unique identifiers or "tokens." These tokens serve as placeholders and have no value outside of the specific transaction context. If intercepted, tokens are meaningless and cannot be used to access the original sensitive data. This method significantly reduces the risk of fraud and data breaches, as the actual payment information is not stored or transmitted.
Together, encryption and tokenization form a powerful security framework. Encryption ensures that data is protected during transmission, while tokenization minimizes the risk of exposing sensitive information by replacing it with secure, non-sensitive tokens.
These technologies are integral to modern payment platforms, providing a robust defense against cyber threats. By implementing advanced encryption and tokenization techniques, businesses can enhance the security of digital transactions, ensuring that users' financial and personal information remains safe. This comprehensive approach not only builds user trust but also fortifies the overall security infrastructure of digital payment systems. As cyber threats evolve, the continued advancement of encryption and tokenization will be crucial in maintaining secure and reliable payment processes.

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