<?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\Mime;

/**
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Xavier De Cock <xdecock@gmail.com>
 *
 * @internal
 */
final class CharacterStream
{
    /** Pre-computed for optimization */
    private const UTF8_LENGTH_MAP = [
        "\x00" => 1, "\x01" => 1, "\x02" => 1, "\x03" => 1, "\x04" => 1, "\x05" => 1, "\x06" => 1, "\x07" => 1,
        "\x08" => 1, "\x09" => 1, "\x0a" => 1, "\x0b" => 1, "\x0c" => 1, "\x0d" => 1, "\x0e" => 1, "\x0f" => 1,
        "\x10" => 1, "\x11" => 1, "\x12" => 1, "\x13" => 1, "\x14" => 1, "\x15" => 1, "\x16" => 1, "\x17" => 1,
        "\x18" => 1, "\x19" => 1, "\x1a" => 1, "\x1b" => 1, "\x1c" => 1, "\x1d" => 1, "\x1e" => 1, "\x1f" => 1,
        "\x20" => 1, "\x21" => 1, "\x22" => 1, "\x23" => 1, "\x24" => 1, "\x25" => 1, "\x26" => 1, "\x27" => 1,
        "\x28" => 1, "\x29" => 1, "\x2a" => 1, "\x2b" => 1, "\x2c" => 1, "\x2d" => 1, "\x2e" => 1, "\x2f" => 1,
        "\x30" => 1, "\x31" => 1, "\x32" => 1, "\x33" => 1, "\x34" => 1, "\x35" => 1, "\x36" => 1, "\x37" => 1,
        "\x38" => 1, "\x39" => 1, "\x3a" => 1, "\x3b" => 1, "\x3c" => 1, "\x3d" => 1, "\x3e" => 1, "\x3f" => 1,
        "\x40" => 1, "\x41" => 1, "\x42" => 1, "\x43" => 1, "\x44" => 1, "\x45" => 1, "\x46" => 1, "\x47" => 1,
        "\x48" => 1, "\x49" => 1, "\x4a" => 1, "\x4b" => 1, "\x4c" => 1, "\x4d" => 1, "\x4e" => 1, "\x4f" => 1,
        "\x50" => 1, "\x51" => 1, "\x52" => 1, "\x53" => 1, "\x54" => 1, "\x55" => 1, "\x56" => 1, "\x57" => 1,
        "\x58" => 1, "\x59" => 1, "\x5a" => 1, "\x5b" => 1, "\x5c" => 1, "\x5d" => 1, "\x5e" => 1, "\x5f" => 1,
        "\x60" => 1, "\x61" => 1, "\x62" => 1, "\x63" => 1, "\x64" => 1, "\x65" => 1, "\x66" => 1, "\x67" => 1,
        "\x68" => 1, "\x69" => 1, "\x6a" => 1, "\x6b" => 1, "\x6c" => 1, "\x6d" => 1, "\x6e" => 1, "\x6f" => 1,
        "\x70" => 1, "\x71" => 1, "\x72" => 1, "\x73" => 1, "\x74" => 1, "\x75" => 1, "\x76" => 1, "\x77" => 1,
        "\x78" => 1, "\x79" => 1, "\x7a" => 1, "\x7b" => 1, "\x7c" => 1, "\x7d" => 1, "\x7e" => 1, "\x7f" => 1,
        "\x80" => 0, "\x81" => 0, "\x82" => 0, "\x83" => 0, "\x84" => 0, "\x85" => 0, "\x86" => 0, "\x87" => 0,
        "\x88" => 0, "\x89" => 0, "\x8a" => 0, "\x8b" => 0, "\x8c" => 0, "\x8d" => 0, "\x8e" => 0, "\x8f" => 0,
        "\x90" => 0, "\x91" => 0, "\x92" => 0, "\x93" => 0, "\x94" => 0, "\x95" => 0, "\x96" => 0, "\x97" => 0,
        "\x98" => 0, "\x99" => 0, "\x9a" => 0, "\x9b" => 0, "\x9c" => 0, "\x9d" => 0, "\x9e" => 0, "\x9f" => 0,
        "\xa0" => 0, "\xa1" => 0, "\xa2" => 0, "\xa3" => 0, "\xa4" => 0, "\xa5" => 0, "\xa6" => 0, "\xa7" => 0,
        "\xa8" => 0, "\xa9" => 0, "\xaa" => 0, "\xab" => 0, "\xac" => 0, "\xad" => 0, "\xae" => 0, "\xaf" => 0,
        "\xb0" => 0, "\xb1" => 0, "\xb2" => 0, "\xb3" => 0, "\xb4" => 0, "\xb5" => 0, "\xb6" => 0, "\xb7" => 0,
        "\xb8" => 0, "\xb9" => 0, "\xba" => 0, "\xbb" => 0, "\xbc" => 0, "\xbd" => 0, "\xbe" => 0, "\xbf" => 0,
        "\xc0" => 2, "\xc1" => 2, "\xc2" => 2, "\xc3" => 2, "\xc4" => 2, "\xc5" => 2, "\xc6" => 2, "\xc7" => 2,
        "\xc8" => 2, "\xc9" => 2, "\xca" => 2, "\xcb" => 2, "\xcc" => 2, "\xcd" => 2, "\xce" => 2, "\xcf" => 2,
        "\xd0" => 2, "\xd1" => 2, "\xd2" => 2, "\xd3" => 2, "\xd4" => 2, "\xd5" => 2, "\xd6" => 2, "\xd7" => 2,
        "\xd8" => 2, "\xd9" => 2, "\xda" => 2, "\xdb" => 2, "\xdc" => 2, "\xdd" => 2, "\xde" => 2, "\xdf" => 2,
        "\xe0" => 3, "\xe1" => 3, "\xe2" => 3, "\xe3" => 3, "\xe4" => 3, "\xe5" => 3, "\xe6" => 3, "\xe7" => 3,
        "\xe8" => 3, "\xe9" => 3, "\xea" => 3, "\xeb" => 3, "\xec" => 3, "\xed" => 3, "\xee" => 3, "\xef" => 3,
        "\xf0" => 4, "\xf1" => 4, "\xf2" => 4, "\xf3" => 4, "\xf4" => 4, "\xf5" => 4, "\xf6" => 4, "\xf7" => 4,
        "\xf8" => 5, "\xf9" => 5, "\xfa" => 5, "\xfb" => 5, "\xfc" => 6, "\xfd" => 6, "\xfe" => 0, "\xff" => 0,
    ];

    private string $data = '';
    private int $dataSize = 0;
    private array $map = [];
    private int $charCount = 0;
    private int $currentPos = 0;
    private int $fixedWidth = 0;

    /**
     * @param resource|string $input
     */
    public function __construct($input, ?string $charset = 'utf-8')
    {
        $charset = strtolower(trim($charset)) ?: 'utf-8';
        if ('utf-8' === $charset || 'utf8' === $charset) {
            $this->fixedWidth = 0;
            $this->map = ['p' => [], 'i' => []];
        } else {
            switch ($charset) {
                // 16 bits
                case 'ucs2':
                case 'ucs-2':
                case 'utf16':
                case 'utf-16':
                    $this->fixedWidth = 2;
                    break;

                    // 32 bits
                case 'ucs4':
                case 'ucs-4':
                case 'utf32':
                case 'utf-32':
                    $this->fixedWidth = 4;
                    break;

                    // 7-8 bit charsets: (us-)?ascii, (iso|iec)-?8859-?[0-9]+, windows-?125[0-9], cp-?[0-9]+, ansi, macintosh,
                //                   koi-?7, koi-?8-?.+, mik, (cork|t1), v?iscii
                    // and fallback
                default:
                    $this->fixedWidth = 1;
            }
        }
        if (\is_resource($input)) {
            $blocks = 16372;
            while (false !== $read = fread($input, $blocks)) {
                $this->write($read);
            }
        } else {
            $this->write($input);
        }
    }

    public function read(int $length): ?string
    {
        if ($this->currentPos >= $this->charCount) {
            return null;
        }
        $length = ($this->currentPos + $length > $this->charCount) ? $this->charCount - $this->currentPos : $length;
        if ($this->fixedWidth > 0) {
            $len = $length * $this->fixedWidth;
            $ret = substr($this->data, $this->currentPos * $this->fixedWidth, $len);
            $this->currentPos += $length;
        } else {
            $end = $this->currentPos + $length;
            $end = $end > $this->charCount ? $this->charCount : $end;
            $ret = '';
            $start = 0;
            if ($this->currentPos > 0) {
                $start = $this->map['p'][$this->currentPos - 1];
            }
            $to = $start;
            for (; $this->currentPos < $end; ++$this->currentPos) {
                if (isset($this->map['i'][$this->currentPos])) {
                    $ret .= substr($this->data, $start, $to - $start).'?';
                    $start = $this->map['p'][$this->currentPos];
                } else {
                    $to = $this->map['p'][$this->currentPos];
                }
            }
            $ret .= substr($this->data, $start, $to - $start);
        }

        return $ret;
    }

    public function readBytes(int $length): ?array
    {
        if (null !== $read = $this->read($length)) {
            return array_map('ord', str_split($read, 1));
        }

        return null;
    }

    public function setPointer(int $charOffset): void
    {
        if ($this->charCount < $charOffset) {
            $charOffset = $this->charCount;
        }
        $this->currentPos = $charOffset;
    }

    public function write(string $chars): void
    {
        $ignored = '';
        $this->data .= $chars;
        if ($this->fixedWidth > 0) {
            $strlen = \strlen($chars);
            $ignoredL = $strlen % $this->fixedWidth;
            $ignored = $ignoredL ? substr($chars, -$ignoredL) : '';
            $this->charCount += ($strlen - $ignoredL) / $this->fixedWidth;
        } else {
            $this->charCount += $this->getUtf8CharPositions($chars, $this->dataSize, $ignored);
        }
        $this->dataSize = \strlen($this->data) - \strlen($ignored);
    }

    private function getUtf8CharPositions(string $string, int $startOffset, string &$ignoredChars): int
    {
        $strlen = \strlen($string);
        $charPos = \count($this->map['p']);
        $foundChars = 0;
        $invalid = false;
        for ($i = 0; $i < $strlen; ++$i) {
            $char = $string[$i];
            $size = self::UTF8_LENGTH_MAP[$char];
            if (0 == $size) {
                /* char is invalid, we must wait for a resync */
                $invalid = true;
                continue;
            }

            if ($invalid) {
                /* We mark the chars as invalid and start a new char */
                $this->map['p'][$charPos + $foundChars] = $startOffset + $i;
                $this->map['i'][$charPos + $foundChars] = true;
                ++$foundChars;
                $invalid = false;
            }
            if (($i + $size) > $strlen) {
                $ignoredChars = substr($string, $i);
                break;
            }
            for ($j = 1; $j < $size; ++$j) {
                $char = $string[$i + $j];
                if ($char > "\x7F" && $char < "\xC0") {
                    // Valid - continue parsing
                } else {
                    /* char is invalid, we must wait for a resync */
                    $invalid = true;
                    continue 2;
                }
            }
            /* Ok we got a complete char here */
            $this->map['p'][$charPos + $foundChars] = $startOffset + $i + $size;
            $i += $j - 1;
            ++$foundChars;
        }

        return $foundChars;
    }
}

• [D] Crypto
• [D] DependencyInjection
• [D] Encoder
• [D] Exception
• [D] Header
• [D] Part
• [D] Resources
• [D] Test
• [F] Address.php
  Delete
• [F] BodyRendererInterface.php
  Delete
• [F] CHANGELOG.md
  Delete
• [F] CharacterStream.php
  Delete
• [F] composer.json
  Delete
• [F] Email.php
  Delete
• [F] FileBinaryMimeTypeGuesser.php
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• [F] FileinfoMimeTypeGuesser.php
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• [F] LICENSE
  Delete
• [F] Message.php
  Delete
• [F] MessageConverter.php
  Delete
• [F] MimeTypeGuesserInterface.php
  Delete
• [F] MimeTypes.php
  Delete
• [F] MimeTypesInterface.php
  Delete
• [F] RawMessage.php
  Delete
• [F] README.md
  Delete

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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.
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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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