<?php
/*
 * PHP QR Code encoder
 *
 * Masking
 *
 * Based on libqrencode C library distributed under LGPL 2.1
 * Copyright (C) 2006, 2007, 2008, 2009 Kentaro Fukuchi <fukuchi@megaui.net>
 *
 * PHP QR Code is distributed under LGPL 3
 * Copyright (C) 2010 Dominik Dzienia <deltalab at poczta dot fm>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
define('N1', 3);
define('N2', 3);
define('N3', 40);
define('N4', 10);
class QRmask
{

    public $runLength = array();

    //----------------------------------------------------------------------
    public function __construct()
    {
        $this->runLength = array_fill(0, QRSPEC_WIDTH_MAX + 1, 0);
    }

    //----------------------------------------------------------------------
    public function writeFormatInformation($width, &$frame, $mask, $level)
    {
        $blacks = 0;
        $format = QRspec::getFormatInfo($mask, $level);
        for ($i = 0; $i < 8; $i++) {
            if ($format & 1) {
                $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 = $format >> 1;
        }
        for ($i = 0; $i < 7; $i++) {
            if ($format & 1) {
                $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 = $format >> 1;
        }

        return $blacks;
    }

    //----------------------------------------------------------------------
    public function mask0($x, $y)
    {
        return ($x + $y) & 1;
    }

    public function mask1($x, $y)
    {
        return ($y & 1);
    }

    public function mask2($x, $y)
    {
        return ($x % 3);
    }

    public function mask3($x, $y)
    {
        return ($x + $y) % 3;
    }

    public function mask4($x, $y)
    {
        return (((int)($y / 2)) + ((int)($x / 3))) & 1;
    }

    public function mask5($x, $y)
    {
        return (($x * $y) & 1) + ($x * $y) % 3;
    }

    public function mask6($x, $y)
    {
        return ((($x * $y) & 1) + ($x * $y) % 3) & 1;
    }

    public function mask7($x, $y)
    {
        return ((($x * $y) % 3) + (($x + $y) & 1)) & 1;
    }

    //----------------------------------------------------------------------
    private function generateMaskNo($maskNo, $width, $frame)
    {
        $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) {
                    $bitMask[$y][$x] = 0;
                } else {
                    $maskFunc        = call_user_func(array($this, 'mask' . $maskNo), $x, $y);
                    $bitMask[$y][$x] = ($maskFunc == 0) ? 1 : 0;
                }

            }
        }

        return $bitMask;
    }

    //----------------------------------------------------------------------
    public static function serial($bitFrame)
    {
        $codeArr = array();
        foreach ($bitFrame as $line)
            $codeArr[] = join('', $line);

        return gzcompress(join("\n", $codeArr), 9);
    }

    //----------------------------------------------------------------------
    public static function unserial($code)
    {
        $codeArr   = array();
        $codeLines = explode("\n", gzuncompress($code));
        foreach ($codeLines as $line)
            $codeArr[] = str_split($line);

        return $codeArr;
    }

    //----------------------------------------------------------------------
    public function makeMaskNo($maskNo, $width, $s, &$d, $maskGenOnly = false)
    {
        $b        = 0;
        $bitMask  = array();
        $fileName = QR_CACHE_DIR . 'mask_' . $maskNo . DIRECTORY_SEPARATOR . 'mask_' . $width . '_' . $maskNo . '.dat';
        if (QR_CACHEABLE) {
            if (file_exists($fileName)) {
                $bitMask = self::unserial(file_get_contents($fileName));
            } else {
                $bitMask = $this->generateMaskNo($maskNo, $width, $s, $d);
                if (!file_exists(QR_CACHE_DIR . 'mask_' . $maskNo))
                    mkdir(QR_CACHE_DIR . 'mask_' . $maskNo);
                file_put_contents($fileName, self::serial($bitMask));
            }
        } else {
            $bitMask = $this->generateMaskNo($maskNo, $width, $s, $d);
        }
        if ($maskGenOnly)
            return;
        $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;
    }

    //----------------------------------------------------------------------
    public function makeMask($width, $frame, $maskNo, $level)
    {
        $masked = array_fill(0, $width, str_repeat("\0", $width));
        $this->makeMaskNo($maskNo, $width, $frame, $masked);
        $this->writeFormatInformation($width, $masked, $maskNo, $level);

        return $masked;
    }

    //----------------------------------------------------------------------
    public function calcN1N3($length)
    {
        $demerit = 0;
        for ($i = 0; $i < $length; $i++) {
            if ($this->runLength[$i] >= 5) {
                $demerit += (N1 + ($this->runLength[$i] - 5));
            }
            if ($i & 1) {
                if (($i >= 3) && ($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))) {
                            $demerit += N3;
                        } else if ((($i + 3) >= $length) || ($this->runLength[$i + 3] >= (4 * $fact))) {
                            $demerit += N3;
                        }
                    }
                }
            }
        }

        return $demerit;
    }

    //----------------------------------------------------------------------
    public function evaluateSymbol($width, $frame)
    {
        $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) {
                        $demerit += N2;
                    }
                }
                if (($x == 0) && (ord($frameY[$x]) & 1)) {
                    $this->runLength[0]     = -1;
                    $head                   = 1;
                    $this->runLength[$head] = 1;
                } else if ($x > 0) {
                    if ((ord($frameY[$x]) ^ ord($frameY[$x - 1])) & 1) {
                        $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;
                } else if ($y > 0) {
                    if ((ord($frame[$y][$x]) ^ ord($frame[$y - 1][$x])) & 1) {
                        $head++;
                        $this->runLength[$head] = 1;
                    } else {
                        $this->runLength[$head]++;
                    }
                }
            }
            $demerit += $this->calcN1N3($head + 1);
        }

        return $demerit;
    }

    //----------------------------------------------------------------------
    public function mask($width, $frame, $level)
    {
        $minDemerit    = PHP_INT_MAX;
        $bestMaskNum   = 0;
        $bestMask      = array();
        $checked_masks = array(0, 1, 2, 3, 4, 5, 6, 7);
        if (QR_FIND_FROM_RANDOM !== false) {
            $howManuOut = 8 - (QR_FIND_FROM_RANDOM % 9);
            for ($i = 0; $i < $howManuOut; $i++) {
                $remPos = rand(0, count($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) * N4);
            $demerit += $this->evaluateSymbol($width, $mask);
            if ($demerit < $minDemerit) {
                $minDemerit  = $demerit;
                $bestMask    = $mask;
                $bestMaskNum = $i;
            }
        }

        return $bestMask;
    }

    //----------------------------------------------------------------------
}
