<?php
/**
 * Jingga
 *
 * PHP Version 8.2
 *
 * @package   phpOMS\Utils\Barcode
 * @author    Nicola Asuni - Tecnick.com LTD - www.tecnick.com <info@tecnick.com>
 * @copyright Copyright (C) 2010 - 2014  Nicola Asuni - Tecnick.com LTD
 * @license   GNU-LGPL v3 (http://www.gnu.org/copyleft/lesser.html)
 * @version   1.0.0
 * @link      https://jingga.app
 */
declare(strict_types=1);

namespace phpOMS\Utils\Barcode;

/**
 * QR class.
 *
 * @package phpOMS\Utils\Barcode
 * @license GNU-LGPL v3 (http://www.gnu.org/copyleft/lesser.html)
 * @link    https://jingga.app
 * @since   1.0.0
 */
class QR extends TwoDAbstract
{
    /**
     * Error correction level.
     *
     * @var int
     * @since 1.0.0
     */
    public const QR_ECLEVEL_L = 0;

    /**
     * Error correction level.
     *
     * @var int
     * @since 1.0.0
     */
    public const QR_ECLEVEL_M = 1;

    /**
     * Error correction level.
     *
     * @var int
     * @since 1.0.0
     */
    public const QR_ECLEVEL_Q = 2;

    /**
     * Error correction level.
     *
     * @var int
     * @since 1.0.0
     */
    public const QR_ECLEVEL_H = 3;

    private const QRCODEDEFS = true;

    private const QR_MODE_NL = -1;

    private const QR_MODE_NM = 0;

    private const QR_MODE_AN = 1;

    private const QR_MODE_8B = 2;

    private const QR_MODE_KJ = 3;

    private const QR_MODE_ST = 4;

    private const QRSPEC_VERSION_MAX = 40;

    private const QRSPEC_WIDTH_MAX = 177;

    private const QRCAP_WIDTH = 0;

    private const QRCAP_WORDS = 1;

    private const QRCAP_REMINDER = 2;

    private const QRCAP_EC = 3;

    private const STRUCTURE_HEADER_BITS = 20;

    private const MAX_STRUCTURED_SYMBOLS = 16;

    private const N1 = 3;

    private const N2 = 3;

    private const N3 = 40;

    private const N4 = 10;

    private const QR_FIND_BEST_MASK = true;

    private const QR_FIND_FROM_RANDOM = 2;

    private const QR_DEFAULT_MASK = 2;

    /**
     * Alphabet-numeric convesion table.
     *
     * @var array
     * @since 1.0.0
     */
    private const AN_TABLE = [
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43,
         0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 44, -1, -1, -1, -1, -1,
        -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
        25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    ];

    /**
     * Array Table of the capacity of symbols.
     * See Table 1 (pp.13) and Table 12-16 (pp.30-36), JIS X0510:2004.
     *
     * @var array
     * @since 1.0.0
     */
    private const CAPACITY = [
        [0,    0, 0, [0,    0,    0,    0]],
        [21,   26, 0, [7,   10,   13,   17]], //  1
        [25,   44, 7, [10,   16,   22,   28]],
        [29,   70, 7, [15,   26,   36,   44]],
        [33,  100, 7, [20,   36,   52,   64]],
        [37,  134, 7, [26,   48,   72,   88]], //  5
        [41,  172, 7, [36,   64,   96,  112]],
        [45,  196, 0, [40,   72,  108,  130]],
        [49,  242, 0, [48,   88,  132,  156]],
        [53,  292, 0, [60,  110,  160,  192]],
        [57,  346, 0, [72,  130,  192,  224]], // 10
        [61,  404, 0, [80,  150,  224,  264]],
        [65,  466, 0, [96,  176,  260,  308]],
        [69,  532, 0, [104,  198,  288,  352]],
        [73,  581, 3, [120,  216,  320,  384]],
        [77,  655, 3, [132,  240,  360,  432]], // 15
        [81,  733, 3, [144,  280,  408,  480]],
        [85,  815, 3, [168,  308,  448,  532]],
        [89,  901, 3, [180,  338,  504,  588]],
        [93,  991, 3, [196,  364,  546,  650]],
        [97, 1085, 3, [224,  416,  600,  700]], // 20
        [101, 1156, 4, [224,  442,  644,  750]],
        [105, 1258, 4, [252,  476,  690,  816]],
        [109, 1364, 4, [270,  504,  750,  900]],
        [113, 1474, 4, [300,  560,  810,  960]],
        [117, 1588, 4, [312,  588,  870, 1050]], // 25
        [121, 1706, 4, [336,  644,  952, 1110]],
        [125, 1828, 4, [360,  700, 1020, 1200]],
        [129, 1921, 3, [390,  728, 1050, 1260]],
        [133, 2051, 3, [420,  784, 1140, 1350]],
        [137, 2185, 3, [450,  812, 1200, 1440]], // 30
        [141, 2323, 3, [480,  868, 1290, 1530]],
        [145, 2465, 3, [510,  924, 1350, 1620]],
        [149, 2611, 3, [540,  980, 1440, 1710]],
        [153, 2761, 3, [570, 1036, 1530, 1800]],
        [157, 2876, 0, [570, 1064, 1590, 1890]], // 35
        [161, 3034, 0, [600, 1120, 1680, 1980]],
        [165, 3196, 0, [630, 1204, 1770, 2100]],
        [169, 3362, 0, [660, 1260, 1860, 2220]],
        [173, 3532, 0, [720, 1316, 1950, 2310]],
        [177, 3706, 0, [750, 1372, 2040, 2430]],  // 40
    ];

    /**
     * Array Length indicator.
     *
     * @var array
     * @since 1.0.0
     */
    private const LENGTH_TABLE_BITS = [
        [10, 12, 14],
        [9, 11, 13],
        [8, 16, 16],
        [8, 10, 12],
    ];

    /**
     * Array Table of the error correction code (Reed-Solomon block).
     * See Table 12-16 (pp.30-36), JIS X0510:2004.
     *
     * @var array
     * @since 1.0.0
     */
    private const ECC_TABLE = [
        [[0,  0], [0,  0], [0,  0], [0,  0]],
        [[1,  0], [1,  0], [1,  0], [1,  0]], //  1
        [[1,  0], [1,  0], [1,  0], [1,  0]],
        [[1,  0], [1,  0], [2,  0], [2,  0]],
        [[1,  0], [2,  0], [2,  0], [4,  0]],
        [[1,  0], [2,  0], [2,  2], [2,  2]], //  5
        [[2,  0], [4,  0], [4,  0], [4,  0]],
        [[2,  0], [4,  0], [2,  4], [4,  1]],
        [[2,  0], [2,  2], [4,  2], [4,  2]],
        [[2,  0], [3,  2], [4,  4], [4,  4]],
        [[2,  2], [4,  1], [6,  2], [6,  2]], // 10
        [[4,  0], [1,  4], [4,  4], [3,  8]],
        [[2,  2], [6,  2], [4,  6], [7,  4]],
        [[4,  0], [8,  1], [8,  4], [12,  4]],
        [[3,  1], [4,  5], [11,  5], [11,  5]],
        [[5,  1], [5,  5], [5,  7], [11,  7]], // 15
        [[5,  1], [7,  3], [15,  2], [3, 13]],
        [[1,  5], [10,  1], [1, 15], [2, 17]],
        [[5,  1], [9,  4], [17,  1], [2, 19]],
        [[3,  4], [3, 11], [17,  4], [9, 16]],
        [[3,  5], [3, 13], [15,  5], [15, 10]], // 20
        [[4,  4], [17,  0], [17,  6], [19,  6]],
        [[2,  7], [17,  0], [7, 16], [34,  0]],
        [[4,  5], [4, 14], [11, 14], [16, 14]],
        [[6,  4], [6, 14], [11, 16], [30,  2]],
        [[8,  4], [8, 13], [7, 22], [22, 13]], // 25
        [[10,  2], [19,  4], [28,  6], [33,  4]],
        [[8,  4], [22,  3], [8, 26], [12, 28]],
        [[3, 10], [3, 23], [4, 31], [11, 31]],
        [[7,  7], [21,  7], [1, 37], [19, 26]],
        [[5, 10], [19, 10], [15, 25], [23, 25]], // 30
        [[13,  3], [2, 29], [42,  1], [23, 28]],
        [[17,  0], [10, 23], [10, 35], [19, 35]],
        [[17,  1], [14, 21], [29, 19], [11, 46]],
        [[13,  6], [14, 23], [44,  7], [59,  1]],
        [[12,  7], [12, 26], [39, 14], [22, 41]], // 35
        [[6, 14], [6, 34], [46, 10], [2, 64]],
        [[17,  4], [29, 14], [49, 10], [24, 46]],
        [[4, 18], [13, 32], [48, 14], [42, 32]],
        [[20,  4], [40,  7], [43, 22], [10, 67]],
        [[19,  6], [18, 31], [34, 34], [20, 61]], // 40
    ];

    /**
     * Array Positions of alignment patterns.
     * This array includes only the second and the third position of the alignment patterns. Rest of them can be calculated from the distance between them.
     * See Table 1 in Appendix E (pp.71) of JIS X0510:2004.
     *
     * @var array
     * @since 1.0.0
     */
    private const ALIGNMENT_PATTERN = [
        [0,  0],
        [0,  0], [18,  0], [22,  0], [26,  0], [30,  0], //  1- 5
        [34,  0], [22, 38], [24, 42], [26, 46], [28, 50], //  6-10
        [30, 54], [32, 58], [34, 62], [26, 46], [26, 48], // 11-15
        [26, 50], [30, 54], [30, 56], [30, 58], [34, 62], // 16-20
        [28, 50], [26, 50], [30, 54], [28, 54], [32, 58], // 21-25
        [30, 58], [34, 62], [26, 50], [30, 54], [26, 52], // 26-30
        [30, 56], [34, 60], [30, 58], [34, 62], [30, 54], // 31-35
        [24, 50], [28, 54], [32, 58], [26, 54], [30, 58], // 35-40
    ];

    /**
     * Array Version information pattern (BCH coded).
     * See Table 1 in Appendix D (pp.68) of JIS X0510:2004.
     * size: [QRSPEC_VERSION_MAX - 6]
     *
     * @var array
     * @since 1.0.0
     */
    private const VERSION_PATTERN = [
        0x07c94, 0x085bc, 0x09a99, 0x0a4d3, 0x0bbf6, 0x0c762, 0x0d847, 0x0e60d,
        0x0f928, 0x10b78, 0x1145d, 0x12a17, 0x13532, 0x149a6, 0x15683, 0x168c9,
        0x177ec, 0x18ec4, 0x191e1, 0x1afab, 0x1b08e, 0x1cc1a, 0x1d33f, 0x1ed75,
        0x1f250, 0x209d5, 0x216f0, 0x228ba, 0x2379f, 0x24b0b, 0x2542e, 0x26a64,
        0x27541, 0x28c69,
    ];

    /**
     * Array Format information
     *
     * @var array
     * @since 1.0.0
     */
    private const FORMAT_INFO = [
        [0x77c4, 0x72f3, 0x7daa, 0x789d, 0x662f, 0x6318, 0x6c41, 0x6976],
        [0x5412, 0x5125, 0x5e7c, 0x5b4b, 0x45f9, 0x40ce, 0x4f97, 0x4aa0],
        [0x355f, 0x3068, 0x3f31, 0x3a06, 0x24b4, 0x2183, 0x2eda, 0x2bed],
        [0x1689, 0x13be, 0x1ce7, 0x19d0, 0x0762, 0x0255, 0x0d0c, 0x083b],
    ];

    private const PUT_ALIGNMENT_FILTER = [
        "\xa1\xa1\xa1\xa1\xa1",
        "\xa1\xa0\xa0\xa0\xa1",
        "\xa1\xa0\xa1\xa0\xa1",
        "\xa1\xa0\xa0\xa0\xa1",
        "\xa1\xa1\xa1\xa1\xa1",
    ];

    private const PUT_FINDER = [
        "\xc1\xc1\xc1\xc1\xc1\xc1\xc1",
        "\xc1\xc0\xc0\xc0\xc0\xc0\xc1",
        "\xc1\xc0\xc1\xc1\xc1\xc0\xc1",
        "\xc1\xc0\xc1\xc1\xc1\xc0\xc1",
        "\xc1\xc0\xc1\xc1\xc1\xc0\xc1",
        "\xc1\xc0\xc0\xc0\xc0\xc0\xc1",
        "\xc1\xc1\xc1\xc1\xc1\xc1\xc1",
    ];

    /**
     * Version.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $version = 0;

    /**
     * Levels of error correction. See definitions for possible values.
     *
     * @var int
     * @since 1.0.0
     */
    public int $level = self::QR_ECLEVEL_L;

    /**
     * Encoding mode.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $hint = self::QR_MODE_8B;

    /**
     * Boolean flag, if true the input string will be converted to uppercase.
     *
     * @var bool
     * @since 1.0.0
     */
    protected bool $casesensitive = true;

    /**
     * Structured QR code (not supported yet).
     *
     * @var int
     * @since 1.0.0
     */
    protected int $structured = 0;

    /**
     * Mask data.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $data = [];

    /**
     * Width.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $width = 0;

    /**
     * Frame.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $frame = [];

    /**
     * X position of bit.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $x = 0;

    /**
     * Y position of bit.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $y = 0;

    /**
     * Direction.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $dir = 0;

    /**
     * Single bit value.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $bit = 0;

    /**
     * Data code.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $datacode = [];

    /**
     * Error correction code.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $ecccode = [];

    /**
     * Blocks.
     *
     * @var int
     *
     * @since 1.0.0
     */
    protected int $blocks = 0;

    /**
     * Reed-Solomon blocks.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $rsblocks = []; //of RSblock

    /**
     * Counter.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $count = 0;

    /**
     * Data length.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $dataLength = 0;

    /**
     * Error correction length.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $eccLength = 0;

    /**
     * Value b1.
     *
     * @var int
     * @since 1.0.0
     */
    protected int $b1 = 0;

    /**
     * Run length.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $runLength = [];

    /**
     * Input data string.
     *
     * @var string
     * @since 1.0.0
     */
    protected string $dataStr = '';

    /**
     * Input items.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $items = [];

    /**
     * Reed-Solomon items.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $rsitems = [];

    /**
     * Array of frames.
     *
     * @var array
     * @since 1.0.0
     */
    protected array $frames = [];

    /**
     * {@inheritdoc}
     */
    public function generateCodeArray() : array
    {
        $this->codearray = [];

        if (($this->hint !== self::QR_MODE_8B && $this->hint !== self::QR_MODE_KJ)
            || ($this->version < 0 || $this->version > self::QRSPEC_VERSION_MAX)
        ) {
            return [];
        }

        $this->items = [];
        $this->encodeString($this->content);

        if (empty($this->data)) {
            return [];
        }

        $this->codearray = $this->binarize($this->data);

        return $this->codearray;
    }

    /**
     * Convert the frame in binary form
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function binarize(array $frame) : array
    {
        $bin = [[]];

        foreach ($frame as $row => $cols) {
            $len = \strlen($cols);
            for ($i = 0; $i < $len; ++$i) {
                $bin[$row][$i] = \ord($frame[$row][$i]) & 1;
            }
        }

        return $bin;
    }

    /**
     * Encode the input string to QR code
     *
     * @return void
     *
     * @since 1.0.0
     */
    protected function encodeString(string $string) : void
    {
        $this->dataStr = $string;
        if (!$this->casesensitive) {
            $this->toUpper();
        }

        $ret = $this->splitString();
        if ($ret < 0) {
            return;
        }

        $this->encodeMask(-1);
    }

    /**
     * Encode mask
     *
     * @return void
     *
     * @since 1.0.0
     */
    protected function encodeMask(int $mask) : void
    {
        $spec           = [0, 0, 0, 0, 0];
        $this->datacode = $this->getByteStream($this->items);

        if (empty($this->datacode)) {
            return;
        }

        $spec             = $this->getEccSpec($this->version, $this->level, $spec);
        $this->b1         = $spec[0];
        $this->dataLength = $spec[0] * $spec[1] + $spec[3] * $spec[4];
        $this->eccLength  = ($spec[0] + $spec[3]) * $spec[2];
        $this->ecccode    = \array_fill(0, $this->eccLength, 0);
        $this->blocks     = $spec[0] + $spec[3];
        $ret              = $this->init($spec);

        if ($ret < 0) {
            return;
        }

        $this->count = 0;
        $this->width = self::CAPACITY[$this->version][self::QRCAP_WIDTH];
        $this->frame = $this->newFrame($this->version);
        $this->x     = $this->width - 1;
        $this->y     = $this->width - 1;
        $this->dir   = -1;
        $this->bit   = -1;

        // inteleaved data and ecc codes
        for ($i = 0; $i < $this->dataLength + $this->eccLength; ++$i) {
            $code = $this->getCode();
            $bit  = 0x80;

            for ($j = 0; $j < 8; ++$j) {
                $addr                                = $this->getNextPosition();
                $this->frame[$addr['y']][$addr['x']] = 0x02 | (($bit & $code) !== 0);
                $bit >>= 1;
            }
        }

        // remainder bits
        $j = self::CAPACITY[$this->version][self::QRCAP_REMINDER];
        for ($i = 0; $i < $j; ++$i) {
            $addr                                = $this->getNextPosition();
            $this->frame[$addr['y']][$addr['x']] = 0x02;
        }

        // masking
        $this->runLength = \array_fill(0, self::QRSPEC_WIDTH_MAX + 1, 0);
        if ($mask < 0) {
            $masked = self::QR_FIND_BEST_MASK
                ? $this->mask($this->width, $this->frame, $this->level)
                : $this->makeMask($this->width, $this->frame, (self::QR_DEFAULT_MASK % 8), $this->level);
        } else {
            $masked = $this->makeMask($this->width, $this->frame, $mask, $this->level);
        }

        if (empty($masked)) {
            return;
        }

        $this->data = $masked;
    }

    /**
     * Get frame value at specified position
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function getFrameAt(array $at) : int
    {
        return \ord($this->frame[$at['y']][$at['x']]);
    }

    /**
     * Return the next frame position
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function getNextPosition() : array
    {
        do {
            if ($this->bit === -1) {
                $this->bit = 0;

                return ['x' => $this->x, 'y' => $this->y];
            }

            $x = $this->x;
            $y = $this->y;
            $w = $this->width;

            if ($this->bit === 0) {
                --$x;
                ++$this->bit;
            } else {
                ++$x;
                --$this->bit;

                $y += $this->dir;
            }

            if ($this->dir < 0) {
                if ($y < 0) {
                    $y = 0;
                    $x -= 2;
                    $this->dir = 1;

                    if ($x === 6) {
                        --$x;
                        $y = 9;
                    }
                }
            } elseif ($y === $w) {
                $y = $w - 1;
                $x -= 2;
                $this->dir = -1;

                if ($x === 6) {
                    --$x;
                    $y -= 8;
                }
            }

            if (($x < 0) || ($y < 0)) {
                return [];
            }

            $this->x = $x;
            $this->y = $y;
        } while (\ord($this->frame[$y][$x]) & 0x80);

        return ['x' => $x, 'y' => $y];
    }

    // - - - - - - - - - - - - - - - - - - - - - - - - -

    // QRrawcode

    /**
     * Initialize code.
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function init(array $spec) : int
    {
        $dl      = $spec[1];
        $el      = $spec[2];
        $rs      = $this->init_rs(8, 0x11d, 0, 1, $el, 255 - $dl - $el);
        $blockNo = 0;
        $dataPos = 0;
        $eccPos  = 0;
        $endfor  = $spec[0];

        for ($i = 0; $i < $endfor; ++$i) {
            $ecc                                    = \array_slice($this->ecccode, $eccPos);
            $this->rsblocks[$blockNo]               = [];
            $this->rsblocks[$blockNo]['dataLength'] = $dl;
            $this->rsblocks[$blockNo]['data']       = \array_slice($this->datacode, $dataPos);
            $this->rsblocks[$blockNo]['eccLength']  = $el;
            $ecc                                    = $this->encode_rs_char($rs, $this->rsblocks[$blockNo]['data'], $ecc);
            $this->rsblocks[$blockNo]['ecc']        = $ecc;
            $this->ecccode                          = \array_merge(\array_slice($this->ecccode, 0, $eccPos), $ecc);
            $dataPos += $dl;
            $eccPos  += $el;

            ++$blockNo;
        }
        if ($spec[3] === 0) {
            return 0;
        }

        $dl = $spec[4];
        $el = $spec[2];
        $rs = $this->init_rs(8, 0x11d, 0, 1, $el, 255 - $dl - $el);

        if ($rs === null) {
            return -1;
        }

        $endfor = $spec[3];
        for ($i = 0; $i < $endfor; ++$i) {
            $ecc                                    = \array_slice($this->ecccode, $eccPos);
            $this->rsblocks[$blockNo]               = [];
            $this->rsblocks[$blockNo]['dataLength'] = $dl;
            $this->rsblocks[$blockNo]['data']       = \array_slice($this->datacode, $dataPos);
            $this->rsblocks[$blockNo]['eccLength']  = $el;
            $ecc                                    = $this->encode_rs_char($rs, $this->rsblocks[$blockNo]['data'], $ecc);
            $this->rsblocks[$blockNo]['ecc']        = $ecc;
            $this->ecccode                          = \array_merge(\array_slice($this->ecccode, 0, $eccPos), $ecc);
            $dataPos += $dl;
            $eccPos  += $el;

            ++$blockNo;
        }

        return 0;
    }

    /**
     * Return Reed-Solomon block
     *
     * @return int
     *
     * @since 1.0.0code.
     */
    protected function getCode() : int
    {
        if ($this->count < $this->dataLength) {
            $row = $this->count % $this->blocks;
            $col = $this->count / $this->blocks;

            if ($col >= $this->rsblocks[0]['dataLength']) {
                $row += $this->b1;
            }

            $ret = $this->rsblocks[$row]['data'][$col];
        } elseif ($this->count < $this->dataLength + $this->eccLength) {
            $row = ($this->count - $this->dataLength) % $this->blocks;
            $col = ($this->count - $this->dataLength) / $this->blocks;
            $ret = $this->rsblocks[$row]['ecc'][$col];
        } else {
            return 0;
        }

        ++$this->count;

        return $ret;
    }

    /**
     * Write Format Information on frame and returns the number of black bits
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function writeFormatInformation(int $width, array &$frame, int $mask, int $level) : int
    {
        $blacks = 0;
        $format = $mask < 0 || $mask > 7 || $level < 0 || $level > 3
            ? 0
            : self::FORMAT_INFO[$level][$mask];

        for ($i = 0; $i < 8; ++$i) {
            if (($format & 1) !== 0) {
                $blacks += 2;
                $v = 0x85;
            } else {
                $v = 0x84;
            }

            $frame[8][$width - 1 - $i] = \chr($v);
            if ($i < 6) {
                $frame[$i][8] = \chr($v);
            } else {
                $frame[$i + 1][8] = \chr($v);
            }

            $format >>= 1;
        }

        for ($i = 0; $i < 7; ++$i) {
            if (($format & 1) !== 0) {
                $blacks += 2;
                $v = 0x85;
            } else {
                $v = 0x84;
            }

            $frame[$width - 7 + $i][8] = \chr($v);
            if ($i === 0) {
                $frame[8][7] = \chr($v);
            } else {
                $frame[8][6 - $i] = \chr($v);
            }

            $format >>= 1;
        }

        return $blacks;
    }

    /**
     * Return bitmask
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function generateMaskNo(int $maskNo, int $width, array $frame) : array
    {
        $bitMask = \array_fill(0, $width, \array_fill(0, $width, 0));
        for ($y = 0; $y < $width; ++$y) {
            for ($x = 0; $x < $width; ++$x) {
                if ((\ord($frame[$y][$x]) & 0x80) !== 0) {
                    $bitMask[$y][$x] = 0;
                } else {
                    $maskFunc = 0;
                    switch ($maskNo) {
                        case 0:
                            $maskFunc = ($x + $y) & 1;
                            break;
                        case 1:
                            $maskFunc = $y & 1;
                            break;
                        case 2:
                            $maskFunc = $x % 3;
                            break;
                        case 3:
                            $maskFunc = ($x + $y) % 3;
                            break;
                        case 4:
                            $maskFunc = (((int) ($y / 2)) + ((int) ($x / 3))) & 1;
                            break;
                        case 5:
                            $maskFunc = (($x * $y) & 1) + ($x * $y) % 3;
                            break;
                        case 6:
                            $maskFunc = ((($x * $y) & 1) + ($x * $y) % 3) & 1;
                            break;
                        case 7:
                            $maskFunc = ((($x * $y) % 3) + (($x + $y) & 1)) & 1;
                            break;
                    }

                    $bitMask[$y][$x] = $maskFunc === 0 ? 1 : 0;
                }
            }
        }

        return $bitMask;
    }

    /**
     * makeMaskNo
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function makeMaskNo(int $maskNo, int $width, array $s, array &$d, bool $maskGenOnly = false) : int
    {
        $b       = 0;
        $bitMask = [];
        $bitMask = $this->generateMaskNo($maskNo, $width, $s);

        if ($maskGenOnly) {
            return 0;
        }

        $d = $s;
        for ($y = 0; $y < $width; ++$y) {
            for ($x = 0; $x < $width; ++$x) {
                if ($bitMask[$y][$x] === 1) {
                    $d[$y][$x] = \chr(\ord($s[$y][$x]) ^ ((int) ($bitMask[$y][$x])));
                }

                $b += (int) (\ord($d[$y][$x]) & 1);
            }
        }

        return $b;
    }

    /**
     * makeMask
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function makeMask(int $width, array $frame, int $maskNo, int $level) : array
    {
        $masked = \array_fill(0, $width, \str_repeat("\0", $width));
        $this->makeMaskNo($maskNo, $width, $frame, $masked);
        $this->writeFormatInformation($width, $masked, $maskNo, $level);

        return $masked;
    }

    /**
     * calcN1N3
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function calcN1N3(int $length) : int
    {
        $demerit = 0;
        for ($i = 0; $i < $length; ++$i) {
            if ($this->runLength[$i] >= 5) {
                $demerit += (self::N1 + ($this->runLength[$i] - 5));
            }

            if (($i & 1) !== 0 && (($i >= 3)
                && ($i < ($length - 2)) && ($this->runLength[$i] % 3 === 0))
            ) {
                $fact = (int) ($this->runLength[$i] / 3);

                if (($this->runLength[$i - 2] === $fact)
                    && ($this->runLength[$i - 1] === $fact)
                    && ($this->runLength[$i + 1] === $fact)
                    && ($this->runLength[$i + 2] === $fact)
                ) {
                    if (($this->runLength[$i - 3] < 0) || ($this->runLength[$i - 3] >= (4 * $fact))) {
                        $demerit += self::N3;
                    } elseif (($i + 3) >= $length || $this->runLength[$i + 3] >= (4 * $fact)) {
                        $demerit += self::N3;
                    }
                }
            }
        }

        return $demerit;
    }

    /**
     * evaluateSymbol
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function evaluateSymbol(int $width, array $frame) : int
    {
        $head    = 0;
        $demerit = 0;

        for ($y = 0; $y < $width; ++$y) {
            $head               = 0;
            $this->runLength[0] = 1;
            $frameY             = $frame[$y];

            if ($y > 0) {
                $frameYM = $frame[$y - 1];
            }

            for ($x = 0; $x < $width; ++$x) {
                if (($x > 0) && ($y > 0)) {
                    $b22 = \ord($frameY[$x]) & \ord($frameY[$x - 1]) & \ord($frameYM[$x]) & \ord($frameYM[$x - 1]);
                    $w22 = \ord($frameY[$x]) | \ord($frameY[$x - 1]) | \ord($frameYM[$x]) | \ord($frameYM[$x - 1]);

                    if ((($b22 | ($w22 ^ 1)) & 1) !== 0) {
                        $demerit += self::N2;
                    }
                }

                if (($x === 0) && (\ord($frameY[$x]) & 1)) {
                    $this->runLength[0]     = -1;
                    $head                   = 1;
                    $this->runLength[$head] = 1;
                } elseif ($x > 0) {
                    if (((\ord($frameY[$x]) ^ \ord($frameY[$x - 1])) & 1) !== 0) {
                        ++$head;
                        $this->runLength[$head] = 1;
                    } else {
                        ++$this->runLength[$head];
                    }
                }
            }

            $demerit += $this->calcN1N3($head + 1);
        }

        for ($x = 0; $x < $width; ++$x) {
            $head               = 0;
            $this->runLength[0] = 1;

            for ($y = 0; $y < $width; ++$y) {
                if (($y === 0) && (\ord($frame[$y][$x]) & 1)) {
                    $this->runLength[0]     = -1;
                    $head                   = 1;
                    $this->runLength[$head] = 1;
                } elseif ($y > 0) {
                    if (((\ord($frame[$y][$x]) ^ \ord($frame[$y - 1][$x])) & 1) !== 0) {
                        ++$head;
                        $this->runLength[$head] = 1;
                    } else {
                        ++$this->runLength[$head];
                    }
                }
            }

            $demerit += $this->calcN1N3($head + 1);
        }

        return $demerit;
    }

    /**
     * mask
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function mask(int $width, array $frame, int $level) : array
    {
        $minDemerit    = \PHP_INT_MAX;
        $bestMask      = [];
        $checked_masks = [0, 1, 2, 3, 4, 5, 6, 7];

        if (self::QR_FIND_FROM_RANDOM !== false) {
            $howManuOut = 8 - (self::QR_FIND_FROM_RANDOM % 9);
            for ($i = 0; $i < $howManuOut; ++$i) {
                // @note This is why the same content can result in different QR codes
                $remPos = \array_rand($checked_masks, 1);
                unset($checked_masks[$remPos]);
                $checked_masks = \array_values($checked_masks);
            }
        }

        $bestMask = $frame;
        foreach ($checked_masks as $i) {
            $mask    = \array_fill(0, $width, \str_repeat("\0", $width));
            $demerit = 0;
            $blacks  = 0;
            $blacks  = $this->makeMaskNo($i, $width, $frame, $mask);
            $blacks += $this->writeFormatInformation($width, $mask, $i, $level);
            $blacks  = (int) (100 * $blacks / ($width * $width));
            $demerit = (int) ((int) (\abs($blacks - 50) / 5) * self::N4);
            $demerit += $this->evaluateSymbol($width, $mask);

            if ($demerit < $minDemerit) {
                $minDemerit = $demerit;
                $bestMask   = $mask;
            }
        }

        return $bestMask;
    }

    /**
     * Return true if the character at specified position is a number
     *
     * @return bool
     *
     * @since 1.0.0
     */
    protected function isdigitat(string $str, int $pos) : bool
    {
        if ($pos >= \strlen($str)) {
            return false;
        }

        return \ord($str[$pos]) >= \ord('0') && \ord($str[$pos]) <= \ord('9');
    }

    /**
     * Return true if the character at specified position is an alphanumeric character
     *
     * @return bool
     *
     * @since 1.0.0
     */
    protected function isalnumat(string $str, int $pos) : bool
    {
        if ($pos >= \strlen($str)) {
            return false;
        }

        return $this->lookAnTable(\ord($str[$pos])) >= 0;
    }

    /**
     * identifyMode
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function identifyMode(int $pos) : int
    {
        if ($pos >= \strlen($this->dataStr)) {
            return self::QR_MODE_NL;
        }

        $c = $this->dataStr[$pos];
        if ($this->isdigitat($this->dataStr, $pos)) {
            return self::QR_MODE_NM;
        } elseif ($this->isalnumat($this->dataStr, $pos)) {
            return self::QR_MODE_AN;
        } elseif ($this->hint === self::QR_MODE_KJ) {
            if ($pos + 1 < \strlen($this->dataStr)) {
                $d    = $this->dataStr[$pos + 1];
                $word = (\ord($c) << 8) | \ord($d);

                if (($word >= 0x8140 && $word <= 0x9ffc)
                    || ($word >= 0xe040 && $word <= 0xebbf)
                ) {
                    return self::QR_MODE_KJ;
                }
            }
        }

        return self::QR_MODE_8B;
    }

    /**
     * eatNum
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function eatNum() : int
    {
        $ln = $this->lengthIndicator(self::QR_MODE_NM, $this->version);
        $p  = 0;

        while ($this->isdigitat($this->dataStr, $p)) {
            ++$p;
        }

        $run  = $p;
        $mode = $this->identifyMode($p);

        if ($mode === self::QR_MODE_8B) {
            $dif = $this->estimateBitsModeNum($run) + 4 + $ln
                + $this->estimateBitsMode8(1)         // + 4 + l8
                - $this->estimateBitsMode8($run + 1); // - 4 - l8

            if ($dif > 0) {
                return $this->eat8();
            }
        }
        if ($mode === self::QR_MODE_AN) {
            $dif = $this->estimateBitsModeNum($run) + 4 + $ln
                + $this->estimateBitsModeAn(1)        // + 4 + la
                - $this->estimateBitsModeAn($run + 1);// - 4 - la

            if ($dif > 0) {
                return $this->eatAn();
            }
        }

        $this->items = $this->appendNewInputItem($this->items, self::QR_MODE_NM, $run, \str_split($this->dataStr));

        return $run;
    }

    /**
     * eatAn
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function eatAn() : int
    {
        $la = $this->lengthIndicator(self::QR_MODE_AN,  $this->version);
        $ln = $this->lengthIndicator(self::QR_MODE_NM, $this->version);
        $p  = 1;

        while ($this->isalnumat($this->dataStr, $p)) {
            if ($this->isdigitat($this->dataStr, $p)) {
                $q = $p;
                while ($this->isdigitat($this->dataStr, $q)) {
                    ++$q;
                }

                $dif = $this->estimateBitsModeAn($p) // + 4 + la
                    + $this->estimateBitsModeNum($q - $p) + 4 + $ln
                    - $this->estimateBitsModeAn($q); // - 4 - la

                if ($dif < 0) {
                    break;
                } else {
                    $p = $q;
                }
            } else {
                ++$p;
            }
        }

        $run = $p;
        if (!$this->isalnumat($this->dataStr, $p)) {
            $dif = $this->estimateBitsModeAn($run) + 4 + $la
                + $this->estimateBitsMode8(1) // + 4 + l8
                - $this->estimateBitsMode8($run + 1); // - 4 - l8

            if ($dif > 0) {
                return $this->eat8();
            }
        }

        $this->items = $this->appendNewInputItem($this->items, self::QR_MODE_AN, $run, \str_split($this->dataStr));

        return $run;
    }

    /**
     * eatKanji
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function eatKanji() : int
    {
        $p = 0;
        while ($this->identifyMode($p) === self::QR_MODE_KJ) {
            $p += 2;
        }

        $this->items = $this->appendNewInputItem($this->items, self::QR_MODE_KJ, $p, \str_split($this->dataStr));

        return $p;
    }

    /**
     * eat8
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function eat8() : int
    {
        $la         = $this->lengthIndicator(self::QR_MODE_AN, $this->version);
        $ln         = $this->lengthIndicator(self::QR_MODE_NM, $this->version);
        $p          = 1;
        $dataStrLen = \strlen($this->dataStr);

        while ($p < $dataStrLen) {
            $mode = $this->identifyMode($p);
            if ($mode === self::QR_MODE_KJ) {
                break;
            }

            if ($mode === self::QR_MODE_NM) {
                $q = $p;
                while ($this->isdigitat($this->dataStr, $q)) {
                    ++$q;
                }

                $dif = $this->estimateBitsMode8($p) // + 4 + l8
                    + $this->estimateBitsModeNum($q - $p) + 4 + $ln
                    - $this->estimateBitsMode8($q); // - 4 - l8

                if ($dif < 0) {
                    break;
                } else {
                    $p = $q;
                }
            } elseif ($mode === self::QR_MODE_AN) {
                $q = $p;
                while ($this->isalnumat($this->dataStr, $q)) {
                    ++$q;
                }

                $dif = $this->estimateBitsMode8($p)  // + 4 + l8
                    + $this->estimateBitsModeAn($q - $p) + 4 + $la
                    - $this->estimateBitsMode8($q); // - 4 - l8

                if ($dif < 0) {
                    break;
                } else {
                    $p = $q;
                }
            } else {
                ++$p;
            }
        }

        $run         = $p;
        $this->items = $this->appendNewInputItem($this->items, self::QR_MODE_8B, $run, \str_split($this->dataStr));

        return $run;
    }

    /**
     * splitString
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function splitString() : int
    {
        while (\strlen($this->dataStr) > 0) {
            $mode = $this->identifyMode(0);
            switch ($mode) {
                case self::QR_MODE_NM:
                    $length = $this->eatNum();
                    break;
                case self::QR_MODE_AN:
                    $length = $this->eatAn();
                    break;
                case self::QR_MODE_KJ:
                    $length = $this->hint === self::QR_MODE_KJ
                        ? $this->eatKanji()
                        : $this->eat8();
                    break;
                default:
                    $length = $this->eat8();
                    break;
            }

            if ($length === 0) {
                return 0;
            }

            if ($length < 0) {
                return -1;
            }

            $this->dataStr = \substr($this->dataStr, $length);
        }

        return 0;
    }

    /**
     * toUpper
     *
     * @return string
     *
     * @since 1.0.0
     */
    protected function toUpper() : string
    {
        $stringLen = \strlen($this->dataStr);
        $p         = 0;

        while ($p < $stringLen) {
            $mode = $this->identifyMode(\strlen(\substr($this->dataStr, $p))/*, $this->hint*/);

            if ($mode === self::QR_MODE_KJ) {
                $p += 2;
            } else {
                if (\ord($this->dataStr[$p]) >= \ord('a')
                    && \ord($this->dataStr[$p]) <= \ord('z')
                ) {
                    $this->dataStr[$p] = \chr(\ord($this->dataStr[$p]) - 32);
                }

                ++$p;
            }
        }
        return $this->dataStr;
    }

    /**
     * newInputItem
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function newInputItem(int $mode, int $size, array $data, array $bstream = []) : array
    {
        $setData = \array_slice($data, 0, $size);
        if (\count($setData) < $size) {
            $setData = \array_merge($setData, \array_fill(0, ($size - \count($setData)), 0));
        }

        if (!$this->check($mode, $size, $setData)) {
            return [];
        }

        $inputitem            = [];
        $inputitem['mode']    = $mode;
        $inputitem['size']    = $size;
        $inputitem['data']    = $setData;
        $inputitem['bstream'] = $bstream;

        return $inputitem;
    }

    /**
     * encodeModeNum
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encodeModeNum(array $inputitem, int $version) : array
    {
        $words                = (int) ($inputitem['size'] / 3);
        $inputitem['bstream'] = [];
        $val                  = 0x1;
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, $val);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], $this->lengthIndicator(self::QR_MODE_NM, $version), $inputitem['size']);

        $ord0 = \ord('0');

        for ($i = 0; $i < $words; ++$i) {
            $val = (\ord($inputitem['data'][$i * 3  ]) - $ord0) * 100;
            $val += (\ord($inputitem['data'][$i * 3 + 1]) - $ord0) * 10;
            $val += (\ord($inputitem['data'][$i * 3 + 2]) - $ord0);

            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 10, $val);
        }

        if ($inputitem['size'] - $words * 3 === 1) {
            $val                  = \ord($inputitem['data'][$words * 3]) - $ord0;
            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, $val);
        } elseif (($inputitem['size'] - ($words * 3)) === 2) {
            $val = (\ord($inputitem['data'][$words * 3  ]) - $ord0) * 10;
            $val += (\ord($inputitem['data'][$words * 3 + 1]) - $ord0);

            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 7, $val);
        }

        return $inputitem;
    }

    /**
     * encodeModeAn
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encodeModeAn(array $inputitem, int $version) : array
    {
        $words = (int) ($inputitem['size'] / 2);

        $inputitem['bstream'] = [];
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, 0x02);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], $this->lengthIndicator(self::QR_MODE_AN, $version), $inputitem['size']);

        for ($i = 0; $i < $words; ++$i) {
            $val = $this->lookAnTable(\ord($inputitem['data'][$i * 2])) * 45;
            $val += $this->lookAnTable(\ord($inputitem['data'][($i * 2) + 1]));

            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 11, $val);
        }

        if (($inputitem['size'] & 1) !== 0) {
            $val = $this->lookAnTable(\ord($inputitem['data'][($words * 2)]));

            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 6, $val);
        }

        return $inputitem;
    }

    /**
     * encodeMode8
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encodeMode8(array $inputitem, int $version) : array
    {
        $inputitem['bstream'] = [];
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, 0x4);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], $this->lengthIndicator(self::QR_MODE_8B, $version), $inputitem['size']);

        for ($i = 0; $i < $inputitem['size']; ++$i) {
            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 8, \ord($inputitem['data'][$i]));
        }

        return $inputitem;
    }

    /**
     * encodeModeKanji
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encodeModeKanji(array $inputitem, int $version) : array
    {
        $inputitem['bstream'] = [];
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, 0x8);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], $this->lengthIndicator(self::QR_MODE_KJ, $version), (int) ($inputitem['size'] / 2));

        for ($i = 0; $i < $inputitem['size']; $i += 2) {
            $val = (\ord($inputitem['data'][$i]) << 8) | \ord($inputitem['data'][$i + 1]);

            if ($val <= 0x9ffc) {
                $val -= 0x8140;
            } else {
                $val -= 0xc140;
            }

            $h   = ($val >> 8) * 0xc0;
            $val = ($val & 0xff) + $h;

            $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 13, $val);
        }

        return $inputitem;
    }

    /**
     * encodeModeStructure
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encodeModeStructure(array $inputitem) : array
    {
        $inputitem['bstream'] = [];
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, 0x03);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, \ord($inputitem['data'][1]) - 1);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 4, \ord($inputitem['data'][0]) - 1);
        $inputitem['bstream'] = $this->appendNum($inputitem['bstream'], 8, \ord($inputitem['data'][2]));

        return $inputitem;
    }

    /**
     * encodeBitStream
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encodeBitStream(array $inputitem, int $version) : array
    {
        $inputitem['bstream'] = [];
        $words                = $this->maximumWords($inputitem['mode'], $version);

        if ($inputitem['size'] > $words) {
            $st1 = $this->newInputItem($inputitem['mode'], $words, $inputitem['data']);
            $st2 = $this->newInputItem($inputitem['mode'], $inputitem['size'] - $words, \array_slice($inputitem['data'], $words));
            $st1 = $this->encodeBitStream($st1, $version);
            $st2 = $this->encodeBitStream($st2, $version);

            $inputitem['bstream'] = [];
            $inputitem['bstream'] = $this->appendBitstream($inputitem['bstream'], $st1['bstream']);
            $inputitem['bstream'] = $this->appendBitstream($inputitem['bstream'], $st2['bstream']);
        } else {
            switch($inputitem['mode']) {
                case self::QR_MODE_NM:
                    $inputitem = $this->encodeModeNum($inputitem, $version);
                    break;
                case self::QR_MODE_AN:
                    $inputitem = $this->encodeModeAn($inputitem, $version);
                    break;
                case self::QR_MODE_8B:
                    $inputitem = $this->encodeMode8($inputitem, $version);
                    break;
                case self::QR_MODE_KJ:
                    $inputitem = $this->encodeModeKanji($inputitem, $version);
                    break;
                case self::QR_MODE_ST:
                    $inputitem = $this->encodeModeStructure($inputitem);
                    break;
            }
        }

        return $inputitem;
    }

    /**
     * Append data to an input object.
     * The data is copied and appended to the input object.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function appendNewInputItem(array $items, int $mode, int $size, array $data) : array
    {
        $newitem = $this->newInputItem($mode, $size, $data);

        if (!empty($newitem)) {
            $items[] = $newitem;
        }

        return $items;
    }

    /**
     * insertStructuredAppendHeader
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function insertStructuredAppendHeader(array $items, int $size, int $index, int $parity) : array
    {
        if ($size > self::MAX_STRUCTURED_SYMBOLS
            || $index <= 0
            || $index > self::MAX_STRUCTURED_SYMBOLS
        ) {
            return [];
        }

        $buf   = [$size, $index, $parity];
        $entry = $this->newInputItem(self::QR_MODE_ST, 3, $buf);

        \array_unshift($items, $entry);

        return $items;
    }

    /**
     * calcParity
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function calcParity(array $items) : int
    {
        $parity = 0;
        foreach ($items as $item) {
            if ($item['mode'] !== self::QR_MODE_ST) {
                for ($i = $item['size'] - 1; $i >= 0; --$i) {
                    $parity ^= $item['data'][$i];
                }
            }
        }

        return $parity;
    }

    /**
     * checkModeNum
     *
     * @return bool
     *
     * @since 1.0.0
     */
    protected function checkModeNum(int $size, array $data) : bool
    {
        for ($i = 0; $i < $size; ++$i) {
            if (\ord($data[$i]) < \ord('0') || \ord($data[$i]) > \ord('9')) {
                return false;
            }
        }

        return true;
    }

    /**
     * Look up the alphabet-numeric conversion table (see JIS X0510:2004, pp.19).
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function lookAnTable(int $c) : int
    {
        return $c > 127 ? -1 : self::AN_TABLE[$c];
    }

    /**
     * checkModeAn
     *
     * @return bool
     *
     * @since 1.0.0
     */
    protected function checkModeAn(int $size, array $data) : bool
    {
        for ($i = 0; $i < $size; ++$i) {
            if ($this->lookAnTable(\ord($data[$i])) === -1) {
                return false;
            }
        }

        return true;
    }

    /**
     * estimateBitsModeNum
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function estimateBitsModeNum(int $size) : int
    {
        $w    = (int) ($size / 3);
        $bits = ($w * 10);

        switch($size - ($w * 3)) {
            case 1:
                $bits += 4;
                break;
            case 2:
                $bits += 7;
                break;
        }

        return $bits;
    }

    /**
     * estimateBitsModeAn
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function estimateBitsModeAn(int $size) : int
    {
        $bits = (int) ($size * 5.5); // (size / 2 ) * 11
        if (($size & 1) !== 0) {
            $bits += 6;
        }

        return $bits;
    }

    /**
     * estimateBitsMode8
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function estimateBitsMode8(int $size) : int
    {
        return $size * 8;
    }

    /**
     * estimateBitsModeKanji
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function estimateBitsModeKanji(int $size) : int
    {
        return (int) ($size * 6.5); // (size / 2 ) * 13
    }

    /**
     * checkModeKanji
     *
     * @return bool
     *
     * @since 1.0.0
     */
    protected function checkModeKanji(int $size, array $data) : bool
    {
        if (($size & 1) !== 0) {
            return false;
        }

        for ($i = 0; $i < $size; $i += 2) {
            $val = (\ord($data[$i]) << 8) | \ord($data[$i + 1]);
            if ($val < 0x8140 || ($val > 0x9ffc && $val < 0xe040) || $val > 0xebbf) {
                return false;
            }
        }

        return true;
    }

    /**
     * Validate the input data.
     *
     * @return bool
     *
     * @since 1.0.0
     */
    protected function check(int $mode, int $size, array $data) : bool
    {
        if ($size <= 0) {
            return false;
        }

        switch($mode) {
            case self::QR_MODE_NM:
                return $this->checkModeNum($size, $data);
            case self::QR_MODE_AN:
                return $this->checkModeAn($size, $data);
            case self::QR_MODE_KJ:
                return $this->checkModeKanji($size, $data);
            case self::QR_MODE_8B:
                return true;
            case self::QR_MODE_ST:
                return true;
        }

        return false;
    }

    /**
     * estimateBitStreamSize
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function estimateBitStreamSize(array $items, int $version) : int
    {
        $bits = 0;
        if ($version === 0) {
            $version = 1;
        }

        foreach ($items as $item) {
            switch($item['mode']) {
                case self::QR_MODE_NM:
                    $bits = $this->estimateBitsModeNum($item['size']);
                    break;
                case self::QR_MODE_AN:
                    $bits = $this->estimateBitsModeAn($item['size']);
                    break;
                case self::QR_MODE_8B:
                    $bits = $this->estimateBitsMode8($item['size']);
                    break;
                case self::QR_MODE_KJ:
                    $bits = $this->estimateBitsModeKanji($item['size']);
                    break;
                case self::QR_MODE_ST:
                    return self::STRUCTURE_HEADER_BITS;
                default:
                    return 0;
            }

            $l   = $this->lengthIndicator($item['mode'], $version);
            $m   = 1 << $l;
            $num = (int) (($item['size'] + $m - 1) / $m);
            $bits += $num * (4 + $l);
        }

        return $bits;
    }

    /**
     * estimateVersion
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function estimateVersion(array $items) : int
    {
        $version = 0;
        $prev    = 0;

        do {
            $prev    = $version;
            $bits    = $this->estimateBitStreamSize($items, $prev);
            $version = $this->getMinimumVersion((int) (($bits + 7) / 8), $this->level);

            if ($version < 0) {
                return -1;
            }
        } while ($version > $prev);

        return $version;
    }

    /**
     * lengthOfCode
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function lengthOfCode(int $mode, int $version, int $bits) : int
    {
        $payload = $bits - 4 - $this->lengthIndicator($mode, $version);
        switch($mode) {
            case self::QR_MODE_NM:
                $chunks = (int) ($payload / 10);
                $remain = $payload - $chunks * 10;
                $size   = $chunks * 3;

                if ($remain >= 7) {
                    $size += 2;
                } elseif ($remain >= 4) {
                    ++$size;
                }

                break;
            case self::QR_MODE_AN:
                $chunks = (int) ($payload / 11);
                $remain = $payload - $chunks * 11;
                $size   = $chunks * 2;

                if ($remain >= 6) {
                    ++$size;
                }

                break;
            case self::QR_MODE_8B:
                $size = (int) ($payload / 8);
                break;
            case self::QR_MODE_KJ:
                $size = (int) (($payload / 13) * 2);
                break;
            case self::QR_MODE_ST:
                $size = (int) ($payload / 8);
                break;
            default:
                $size = 0;
                break;
        }

        $maxsize = $this->maximumWords($mode, $version);
        if ($size < 0) {
            $size = 0;
        }

        if ($size > $maxsize) {
            $size = $maxsize;
        }

        return $size;
    }

    /**
     * createBitStream
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function createBitStream(array $items) : array
    {
        $total = 0;
        foreach ($items as $key => $item) {
            $items[$key] = $this->encodeBitStream($item, $this->version);
            $bits        = \count($items[$key]['bstream']);
            $total += $bits;
        }

        return [$items, $total];
    }

    /**
     * convertData
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function convertData(array $items) : array
    {
        $ver = $this->estimateVersion($items);
        if ($ver > $this->version) {
            $this->version = $ver;
        }

        while (true) {
            $cbs   = $this->createBitStream($items);
            $items = $cbs[0];
            $bits  = $cbs[1];

            if ($bits < 0) {
                return [];
            }

            $ver = $this->getMinimumVersion((int) (($bits + 7) / 8), $this->level);
            if ($ver < 0) {
                return [];
            } elseif ($ver > $this->version) {
                $this->version = $ver;
            } else {
                break;
            }
        }

        return $items;
    }

    /**
     * Append Padding Bit to bitstream
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function appendPaddingBit(array $bstream) : array
    {
        if (empty($bstream)) {
            return [];
        }

        $bits     = \count($bstream);
        $maxwords = self::CAPACITY[$this->version][self::QRCAP_WORDS] - self::CAPACITY[$this->version][self::QRCAP_EC][$this->level];
        $maxbits  = $maxwords * 8;

        if ($maxbits === $bits) {
            return $bstream;
        }

        if ($maxbits - $bits < 5) {
            return $this->appendNum($bstream, $maxbits - $bits, 0);
        }

        $bits += 4;
        $words   = (int) (($bits + 7) / 8);
        $padding = [];
        $padding = $this->appendNum($padding, $words * 8 - $bits + 4, 0);
        $padlen  = $maxwords - $words;

        if ($padlen > 0) {
            $padbuf = [];

            for ($i = 0; $i < $padlen; ++$i) {
                $padbuf[$i] = (($i & 1) !== 0) ? 0x11 : 0xec;
            }

            $padding = $this->appendBytes($padding, $padlen, $padbuf);
        }

        return $this->appendBitstream($bstream, $padding);
    }

    /**
     * mergeBitStream
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function mergeBitStream(array $items) : array
    {
        $items = $this->convertData($items);
        if (empty($items)) {
            return [];
        }

        $bstream = [];
        foreach ($items as $item) {
            $bstream = $this->appendBitstream($bstream, $item['bstream']);
        }

        return $bstream;
    }

    /**
     * Returns a stream of bits.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function getBitStream(array $items) : array
    {
        $bstream = $this->mergeBitStream($items);

        return $this->appendPaddingBit($bstream);
    }

    /**
     * Pack all bit streams padding bits into a byte array.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function getByteStream(array $items) : array
    {
        $bstream = $this->getBitStream($items);

        return $this->bitstreamToByte($bstream);
    }

    /**
     * Return an array with zeros
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function allocate(int $setLength) : array
    {
        return \array_fill(0, $setLength, 0);
    }

    /**
     * Return new bitstream from number
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function newFromNum(int $bits, int $num) : array
    {
        $bstream = $this->allocate($bits);
        $mask    = 1 << ($bits - 1);

        for ($i = 0; $i < $bits; ++$i) {
            $bstream[$i] = (($num & $mask) !== 0) ? 1 : 0;
            $mask >>= 1;
        }

        return $bstream;
    }

    /**
     * Return new bitstream from bytes
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function newFromBytes(int $size, array $data) : array
    {
        $bstream = $this->allocate($size * 8);
        $p       = 0;

        for ($i = 0; $i < $size; ++$i) {
            $mask = 0x80;

            for ($j = 0; $j < 8; ++$j) {
                $bstream[$p] = (($data[$i] & $mask) !== 0) ? 1 : 0;
                     $mask >>= 1;

                ++$p;
            }
        }

        return $bstream;
    }

    /**
     * Append one bitstream to another
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function appendBitstream(array $bitstream, array $append) : array
    {
        if (empty($append)) {
            return $bitstream;
        }

        if (empty($bitstream)) {
            return $append;
        }

        return \array_values(\array_merge($bitstream, $append));
    }

    /**
     * Append one bitstream created from number to another
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function appendNum(array $bitstream, int $bits, int $num) : array
    {
        if ($bits === 0) {
            return [];
        }

        $b = $this->newFromNum($bits, $num);

        return $this->appendBitstream($bitstream, $b);
    }

    /**
     * Append one bitstream created from bytes to another
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function appendBytes(array $bitstream, int $size, array $data) : array
    {
        if ($size === 0) {
            return [];
        }

        $b = $this->newFromBytes($size, $data);

        return $this->appendBitstream($bitstream, $b);
    }

    /**
     * Convert bitstream to bytes
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function bitstreamToByte(array $bstream) : array
    {
        $size = \count($bstream);
        if ($size === 0) {
            return [];
        }

        $data  = \array_fill(0, (int) (($size + 7) / 8), 0);
        $bytes = (int) ($size / 8);
        $p     = 0;

        for ($i = 0; $i < $bytes; ++$i) {
            $v = 0;

            for ($j = 0; $j < 8; ++$j) {
                $v <<= 1;
                $v |= $bstream[$p];
                ++$p;
            }

            $data[$i] = $v;
        }

        if (($size & 7) !== 0) {
            $v = 0;

            for ($j = 0; $j < ($size & 7); ++$j) {
                $v <<= 1;
                $v |= $bstream[$p];
                ++$p;
            }

            $data[$bytes] = $v;
        }

        return $data;
    }

    /**
     * Replace a value on the array at the specified position
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function qrstrset(array $srctab, int $x, int $y, string $repl, int $replLen = 0) : array
    {
        $srctab[$y] = \substr_replace(
            $srctab[$y],
            $replLen !== 0 ? \substr($repl, 0, $replLen) : $repl,
            $x,
            $replLen !== 0 ? $replLen : \strlen($repl)
        );

        return $srctab;
    }

    /**
     * Return a version number that satisfies the input code length.
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function getMinimumVersion(int $size, int $level) : int
    {
        for ($i = 1; $i <= self::QRSPEC_VERSION_MAX; ++$i) {
            $words = self::CAPACITY[$i][self::QRCAP_WORDS] - self::CAPACITY[$i][self::QRCAP_EC][$level];
            if ($words >= $size) {
                return $i;
            }
        }

        // the size of input data is greater than QR capacity, try to lover the error correction mode
        return -1;
    }

    /**
     * Return the size of length indicator for the mode and version.
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function lengthIndicator(int $mode, int $version) : int
    {
        if ($mode === self::QR_MODE_ST) {
            return 0;
        }

        if ($version <= 9) {
            $l = 0;
        } elseif ($version <= 26) {
            $l = 1;
        } else {
            $l = 2;
        }

        return self::LENGTH_TABLE_BITS[$mode][$l];
    }

    /**
     * Return the maximum length for the mode and version.
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function maximumWords(int $mode, int $version) : int
    {
        if ($mode === self::QR_MODE_ST) {
            return 3;
        }

        if ($version <= 9) {
            $l = 0;
        } elseif ($version <= 26) {
            $l = 1;
        } else {
            $l = 2;
        }

        $bits  = self::LENGTH_TABLE_BITS[$mode][$l];
        $words = (1 << $bits) - 1;

        if ($mode === self::QR_MODE_KJ) {
            $words *= 2; // the number of bytes is required
        }

        return $words;
    }

    /**
     * Return an array of ECC specification.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function getEccSpec(int $version, int $level, array $spec) : array
    {
        if (\count($spec) < 5) {
            $spec = [0, 0, 0, 0, 0];
        }

        $b1   = self::ECC_TABLE[$version][$level][0];
        $b2   = self::ECC_TABLE[$version][$level][1];
        $data = self::CAPACITY[$version][self::QRCAP_WORDS] - self::CAPACITY[$version][self::QRCAP_EC][$level];
        $ecc  = self::CAPACITY[$version][self::QRCAP_EC][$level];

        if ($b2 === 0) {
            $spec[0] = $b1;
            $spec[1] = (int) ($data / $b1);
            $spec[2] = (int) ($ecc / $b1);
            $spec[3] = 0;
            $spec[4] = 0;
        } else {
            $spec[0] = $b1;
            $spec[1] = (int) ($data / ($b1 + $b2));
            $spec[2] = (int) ($ecc / ($b1 + $b2));
            $spec[3] = $b2;
            $spec[4] = $spec[1] + 1;
        }

        return $spec;
    }

    /**
     * Put an alignment marker.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function putAlignmentMarker(array $frame, int $ox, int $oy) : array
    {
        $yStart = $oy - 2;
        $xStart = $ox - 2;

        for ($y = 0; $y < 5; ++$y) {
            $frame = $this->qrstrset($frame, $xStart, $yStart + $y, self::PUT_ALIGNMENT_FILTER[$y]);
        }

        return $frame;
    }

    /**
     * Put an alignment pattern.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function putAlignmentPattern(int $version, array $frame, int $width) : array
    {
        if ($version < 2) {
            return $frame;
        }

        $d = self::ALIGNMENT_PATTERN[$version][1] - self::ALIGNMENT_PATTERN[$version][0];
        $w = $d < 0
            ? 2
            : (int) (($width - self::ALIGNMENT_PATTERN[$version][0]) / $d + 2);

        if ($w * $w - 3 === 1) {
            $x = self::ALIGNMENT_PATTERN[$version][0];
            $y = self::ALIGNMENT_PATTERN[$version][0];

            return $this->putAlignmentMarker($frame, $x, $y);
        }

        $cx = self::ALIGNMENT_PATTERN[$version][0];
        $wo = $w - 1;

        for ($x = 1; $x < $wo; ++$x) {
            $frame = $this->putAlignmentMarker($frame, 6, $cx);
            $frame = $this->putAlignmentMarker($frame, $cx,  6);

            $cx += $d;
        }

        $cy = self::ALIGNMENT_PATTERN[$version][0];
        for ($y = 0; $y < $wo; ++$y) {
            $cx = self::ALIGNMENT_PATTERN[$version][0];

            for ($x = 0; $x < $wo; ++$x) {
                $frame = $this->putAlignmentMarker($frame, $cx, $cy);

                $cx += $d;
            }

            $cy += $d;
        }

        return $frame;
    }

    /**
     * Put a finder pattern.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function putFinderPattern(array $frame, int $ox, int $oy) : array
    {
        for ($y = 0; $y < 7; ++$y) {
            $frame = $this->qrstrset($frame, $ox, ($oy + $y), self::PUT_FINDER[$y]);
        }

        return $frame;
    }

    /**
     * Return a copy of initialized frame.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function createFrame(int $version) : array
    {
        $width     = self::CAPACITY[$version][self::QRCAP_WIDTH];
        $frameLine = \str_repeat("\0", $width);
        $frame     = \array_fill(0, $width, $frameLine);

        // Finder pattern
        $frame = $this->putFinderPattern($frame, 0, 0);
        $frame = $this->putFinderPattern($frame, $width - 7, 0);
        $frame = $this->putFinderPattern($frame, 0, $width - 7);

        // Separator
        $yOffset = $width - 7;
        for ($y = 0; $y < 7; ++$y) {
            $frame[$y][7]          = "\xc0";
            $frame[$y][$width - 8] = "\xc0";
            $frame[$yOffset][7]    = "\xc0";

            ++$yOffset;
        }

        $setPattern = \str_repeat("\xc0", 8);
        $frame      = $this->qrstrset($frame, 0, 7, $setPattern);
        $frame      = $this->qrstrset($frame, $width - 8, 7, $setPattern);
        $frame      = $this->qrstrset($frame, 0, $width - 8, $setPattern);

        // Format info
        $setPattern = \str_repeat("\x84", 9);
        $frame      = $this->qrstrset($frame, 0, 8, $setPattern);
        $frame      = $this->qrstrset($frame, $width - 8, 8, $setPattern, 8);
        $yOffset    = $width - 8;

        for ($y = 0; $y < 8; ++$y, ++$yOffset) {
            $frame[$y][8]       = "\x84";
            $frame[$yOffset][8] = "\x84";
        }

        // Timing pattern
        $wo = $width - 15;
        for ($i = 1; $i < $wo; ++$i) {
            $frame[6][7 + $i] = \chr(0x90 | ($i & 1));
            $frame[7 + $i][6] = \chr(0x90 | ($i & 1));
        }

        // Alignment pattern
        $frame = $this->putAlignmentPattern($version, $frame, $width);

        // Version information
        if ($version >= 7) {
            $vinf = $version > self::QRSPEC_VERSION_MAX
                ? 0
                : self::VERSION_PATTERN[$version - 7];

            $v = $vinf;
            for ($x = 0; $x < 6; ++$x) {
                for ($y = 0; $y < 3; ++$y) {
                    $frame[($width - 11) + $y][$x] = \chr(0x88 | ($v & 1));
                    $v >>= 1;
                }
            }

            $v = $vinf;
            for ($y = 0; $y < 6; ++$y) {
                for ($x = 0; $x < 3; ++$x) {
                    $frame[$y][$x + ($width - 11)] = \chr(0x88 | ($v & 1));
                    $v >>= 1;
                }
            }
        }

        // and a little bit...
        $frame[$width - 8][8] = "\x81";

        return $frame;
    }

    /**
     * Set new frame for the specified version.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function newFrame(int $version) : array
    {
        if ($version < 1 || $version > self::QRSPEC_VERSION_MAX) {
            return [];
        }

        if (!isset($this->frames[$version])) {
            $this->frames[$version] = $this->createFrame($version);
        }

        if ($this->frames[$version] === null) {
            return [];
        }

        return $this->frames[$version];
    }

    /**
     * Initialize a Reed-Solomon codec and add it to existing rsitems
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function init_rs(int $symsize, int $gfpoly, int $fcr, int $prim, int $nroots, int $pad) : array
    {
        foreach ($this->rsitems as $rs) {
            if (($rs['pad'] !== $pad) || ($rs['nroots'] !== $nroots) || ($rs['mm'] !== $symsize)
                || ($rs['gfpoly'] !== $gfpoly) || ($rs['fcr'] !== $fcr) || ($rs['prim'] !== $prim)
            ) {
                continue;
            }

            return $rs;
        }

        $rs = $this->init_rs_char($symsize, $gfpoly, $fcr, $prim, $nroots, $pad);
        \array_unshift($this->rsitems, $rs);

        return $rs;
    }

    /**
     * modnn
     *
     * @return int
     *
     * @since 1.0.0
     */
    protected function modnn(array $rs, int $x) : int
    {
        while ($x >= $rs['nn']) {
            $x -= $rs['nn'];
            $x = ($x >> $rs['mm']) + ($x & $rs['nn']);
        }

        return $x;
    }

    /**
     * Initialize a Reed-Solomon codec and returns an array of values.
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function init_rs_char(int $symsize, int $gfpoly, int $fcr, int $prim, int $nroots, int $pad) : array
    {
        // Based on Reed solomon encoder by Phil Karn, KA9Q (GNU-LGPLv2)
        // Check parameter ranges
        if ($symsize < 0 || $symsize > 8
            || $fcr < 0 || $fcr >= (1 << $symsize)
            || $prim <= 0 || $prim >= (1 << $symsize)
            || $nroots < 0 || $nroots >= (1 << $symsize)
            || $pad < 0 || $pad >= ((1 << $symsize) - 1 - $nroots)
        ) {
            return [];
        }

        $rs             = [];
        $rs['mm']       = $symsize;
        $rs['nn']       = (1 << $symsize) - 1;
        $rs['pad']      = $pad;
        $rs['alpha_to'] = \array_fill(0, ($rs['nn'] + 1), 0);
        $rs['index_of'] = \array_fill(0, ($rs['nn'] + 1), 0);

        // PHP style macro replacement ;)
        $NN = & $rs['nn'];
        $A0 = & $NN;

        // Generate Galois field lookup tables
        $rs['index_of'][0]   = $A0; // log(zero) = -inf
        $rs['alpha_to'][$A0] = 0; // alpha**-inf = 0
        $sr                  = 1;

        for ($i = 0; $i < $rs['nn']; ++$i) {
            $rs['index_of'][$sr] = $i;
            $rs['alpha_to'][$i]  = $sr;
            $sr <<= 1;

            if (($sr & (1 << $symsize)) !== 0) {
                $sr ^= $gfpoly;
            }

            $sr &= $rs['nn'];
        }

        if ($sr !== 1) {
            // field generator polynomial is not primitive!
            return [];
        }

        // Form RS code generator polynomial from its roots
        $rs['genpoly'] = \array_fill(0, ($nroots + 1), 0);
        $rs['fcr']     = $fcr;
        $rs['prim']    = $prim;
        $rs['nroots']  = $nroots;
        $rs['gfpoly']  = $gfpoly;

        // Find prim-th root of 1, used in decoding
        $iprim = 1;
        while ($iprim % $prim !== 0) {
            $iprim += $rs['nn'];
        }

        $rs['iprim']      = (int) ($iprim / $prim);
        $rs['genpoly'][0] = 1;

        for ($i = 0, $root = $fcr * $prim; $i < $nroots; ++$i, $root += $prim) {
            $rs['genpoly'][$i + 1] = 1;

            // Multiply rs->genpoly[] by  @**(root + x)
            for ($j = $i; $j > 0; --$j) {
                if ($rs['genpoly'][$j] !== 0) {
                    $rs['genpoly'][$j] = $rs['genpoly'][$j - 1] ^ $rs['alpha_to'][$this->modnn($rs, $rs['index_of'][$rs['genpoly'][$j]] + $root)];
                } else {
                    $rs['genpoly'][$j] = $rs['genpoly'][$j - 1];
                }
            }

            // rs->genpoly[0] can never be zero
            $rs['genpoly'][0] = $rs['alpha_to'][$this->modnn($rs, $rs['index_of'][$rs['genpoly'][0]] + $root)];
        }

        // convert rs->genpoly[] to index form for quicker encoding
        for ($i = 0; $i <= $nroots; ++$i) {
            $rs['genpoly'][$i] = $rs['index_of'][$rs['genpoly'][$i]];
        }

        return $rs;
    }

    /**
     * Encode a Reed-Solomon codec and returns the parity array
     *
     * @return array
     *
     * @since 1.0.0
     */
    protected function encode_rs_char(array $rs, array $data, array $parity) : array
    {
        $MM       = & $rs['mm']; // bits per symbol
        $NN       = & $rs['nn']; // the total number of symbols in a RS block
        $ALPHA_TO = & $rs['alpha_to']; // the address of an array of NN elements to convert Galois field elements in index (log) form to polynomial form
        $INDEX_OF = & $rs['index_of']; // the address of an array of NN elements to convert Galois field elements in polynomial form to index (log) form
        $GENPOLY  = & $rs['genpoly']; // an array of NROOTS+1 elements containing the generator polynomial in index form
        $NROOTS   = & $rs['nroots']; // the number of roots in the RS code generator polynomial, which is the same as the number of parity symbols in a block
        $FCR      = & $rs['fcr']; // first consecutive root, index form
        $PRIM     = & $rs['prim']; // primitive element, index form
        $IPRIM    = & $rs['iprim']; // prim-th root of 1, index form
        $PAD      = & $rs['pad']; // the number of pad symbols in a block
        $A0       = & $NN;
        $parity   = \array_fill(0, $NROOTS, 0);

        for ($i = 0; $i < $NN - $NROOTS - $PAD; ++$i) {
            $feedback = $INDEX_OF[$data[$i] ^ $parity[0]];

            if ($feedback !== $A0) {
                // feedback term is non-zero
                // This line is unnecessary when GENPOLY[NROOTS] is unity, as it must
                // always be for the polynomials constructed by init_rs()
                $feedback = $this->modnn($rs, $NN - $GENPOLY[$NROOTS] + $feedback);

                for ($j = 1; $j < $NROOTS; ++$j) {
                    $parity[$j] ^= $ALPHA_TO[$this->modnn($rs, $feedback + $GENPOLY[($NROOTS - $j)])];
                }
            }

            // Shift
            \array_shift($parity);
            $parity[] = $feedback !== $A0
                ? $ALPHA_TO[$this->modnn($rs, $feedback + $GENPOLY[0])]
                : 0;
        }

        return $parity;
    }
}
