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✏️ Editing: QRUtil.js

var QRMode = require('./QRMode');
var QRPolynomial = require('./QRPolynomial');
var QRMath = require('./QRMath');
var QRMaskPattern = require('./QRMaskPattern');

var QRUtil = {

PATTERN_POSITION_TABLE : [
        [],
        [6, 18],
        [6, 22],
        [6, 26],
        [6, 30],
        [6, 34],
        [6, 22, 38],
        [6, 24, 42],
        [6, 26, 46],
        [6, 28, 50],
        [6, 30, 54],        
        [6, 32, 58],
        [6, 34, 62],
        [6, 26, 46, 66],
        [6, 26, 48, 70],
        [6, 26, 50, 74],
        [6, 30, 54, 78],
        [6, 30, 56, 82],
        [6, 30, 58, 86],
        [6, 34, 62, 90],
        [6, 28, 50, 72, 94],
        [6, 26, 50, 74, 98],
        [6, 30, 54, 78, 102],
        [6, 28, 54, 80, 106],
        [6, 32, 58, 84, 110],
        [6, 30, 58, 86, 114],
        [6, 34, 62, 90, 118],
        [6, 26, 50, 74, 98, 122],
        [6, 30, 54, 78, 102, 126],
        [6, 26, 52, 78, 104, 130],
        [6, 30, 56, 82, 108, 134],
        [6, 34, 60, 86, 112, 138],
        [6, 30, 58, 86, 114, 142],
        [6, 34, 62, 90, 118, 146],
        [6, 30, 54, 78, 102, 126, 150],
        [6, 24, 50, 76, 102, 128, 154],
        [6, 28, 54, 80, 106, 132, 158],
        [6, 32, 58, 84, 110, 136, 162],
        [6, 26, 54, 82, 110, 138, 166],
        [6, 30, 58, 86, 114, 142, 170]
    ],

G15 : (1 << 10) | (1 << 8) | (1 << 5) | (1 << 4) | (1 << 2) | (1 << 1) | (1 << 0),
    G18 : (1 << 12) | (1 << 11) | (1 << 10) | (1 << 9) | (1 << 8) | (1 << 5) | (1 << 2) | (1 << 0),
    G15_MASK : (1 << 14) | (1 << 12) | (1 << 10)    | (1 << 4) | (1 << 1),

getBCHTypeInfo : function(data) {
        var d = data << 10;
        while (QRUtil.getBCHDigit(d) - QRUtil.getBCHDigit(QRUtil.G15) >= 0) {
            d ^= (QRUtil.G15 << (QRUtil.getBCHDigit(d) - QRUtil.getBCHDigit(QRUtil.G15) ) );    
        }
        return ( (data << 10) | d) ^ QRUtil.G15_MASK;
    },

getBCHTypeNumber : function(data) {
        var d = data << 12;
        while (QRUtil.getBCHDigit(d) - QRUtil.getBCHDigit(QRUtil.G18) >= 0) {
            d ^= (QRUtil.G18 << (QRUtil.getBCHDigit(d) - QRUtil.getBCHDigit(QRUtil.G18) ) );    
        }
        return (data << 12) | d;
    },

getBCHDigit : function(data) {

var digit = 0;

while (data !== 0) {
            digit++;
            data >>>= 1;
        }

return digit;
    },

getPatternPosition : function(typeNumber) {
        return QRUtil.PATTERN_POSITION_TABLE[typeNumber - 1];
    },

getMask : function(maskPattern, i, j) {
        
        switch (maskPattern) {
            
        case QRMaskPattern.PATTERN000 : return (i + j) % 2 === 0;
        case QRMaskPattern.PATTERN001 : return i % 2 === 0;
        case QRMaskPattern.PATTERN010 : return j % 3 === 0;
        case QRMaskPattern.PATTERN011 : return (i + j) % 3 === 0;
        case QRMaskPattern.PATTERN100 : return (Math.floor(i / 2) + Math.floor(j / 3) ) % 2 === 0;
        case QRMaskPattern.PATTERN101 : return (i * j) % 2 + (i * j) % 3 === 0;
        case QRMaskPattern.PATTERN110 : return ( (i * j) % 2 + (i * j) % 3) % 2 === 0;
        case QRMaskPattern.PATTERN111 : return ( (i * j) % 3 + (i + j) % 2) % 2 === 0;

default :
            throw new Error("bad maskPattern:" + maskPattern);
        }
    },

getErrorCorrectPolynomial : function(errorCorrectLength) {

var a = new QRPolynomial([1], 0);

for (var i = 0; i < errorCorrectLength; i++) {
            a = a.multiply(new QRPolynomial([1, QRMath.gexp(i)], 0) );
        }

return a;
    },

getLengthInBits : function(mode, type) {

if (1 <= type && type < 10) {

// 1 - 9

switch(mode) {
            case QRMode.MODE_NUMBER     : return 10;
            case QRMode.MODE_ALPHA_NUM  : return 9;
            case QRMode.MODE_8BIT_BYTE  : return 8;
            case QRMode.MODE_KANJI      : return 8;
            default :
                throw new Error("mode:" + mode);
            }

} else if (type < 27) {

// 10 - 26

switch(mode) {
            case QRMode.MODE_NUMBER     : return 12;
            case QRMode.MODE_ALPHA_NUM  : return 11;
            case QRMode.MODE_8BIT_BYTE  : return 16;
            case QRMode.MODE_KANJI      : return 10;
            default :
                throw new Error("mode:" + mode);
            }

} else if (type < 41) {

// 27 - 40

switch(mode) {
            case QRMode.MODE_NUMBER     : return 14;
            case QRMode.MODE_ALPHA_NUM  : return 13;
            case QRMode.MODE_8BIT_BYTE  : return 16;
            case QRMode.MODE_KANJI      : return 12;
            default :
                throw new Error("mode:" + mode);
            }

} else {
            throw new Error("type:" + type);
        }
    },

getLostPoint : function(qrCode) {
        
        var moduleCount = qrCode.getModuleCount();
        var lostPoint = 0;
        var row = 0; 
        var col = 0;

// LEVEL1
        
        for (row = 0; row < moduleCount; row++) {

for (col = 0; col < moduleCount; col++) {

var sameCount = 0;
                var dark = qrCode.isDark(row, col);

for (var r = -1; r <= 1; r++) {

if (row + r < 0 || moduleCount <= row + r) {
                        continue;
                    }

for (var c = -1; c <= 1; c++) {

if (col + c < 0 || moduleCount <= col + c) {
                            continue;
                        }

if (r === 0 && c === 0) {
                            continue;
                        }

if (dark === qrCode.isDark(row + r, col + c) ) {
                            sameCount++;
                        }
                    }
                }

if (sameCount > 5) {
                    lostPoint += (3 + sameCount - 5);
                }
            }
        }

// LEVEL2

for (row = 0; row < moduleCount - 1; row++) {
            for (col = 0; col < moduleCount - 1; col++) {
                var count = 0;
                if (qrCode.isDark(row,     col    ) ) count++;
                if (qrCode.isDark(row + 1, col    ) ) count++;
                if (qrCode.isDark(row,     col + 1) ) count++;
                if (qrCode.isDark(row + 1, col + 1) ) count++;
                if (count === 0 || count === 4) {
                    lostPoint += 3;
                }
            }
        }

// LEVEL3

for (row = 0; row < moduleCount; row++) {
            for (col = 0; col < moduleCount - 6; col++) {
                if (qrCode.isDark(row, col) && 
                        !qrCode.isDark(row, col + 1) && 
                         qrCode.isDark(row, col + 2) && 
                         qrCode.isDark(row, col + 3) && 
                         qrCode.isDark(row, col + 4) && 
                        !qrCode.isDark(row, col + 5) && 
                         qrCode.isDark(row, col + 6) ) {
                    lostPoint += 40;
                }
            }
        }

for (col = 0; col < moduleCount; col++) {
            for (row = 0; row < moduleCount - 6; row++) {
                if (qrCode.isDark(row, col) &&
                        !qrCode.isDark(row + 1, col) &&
                         qrCode.isDark(row + 2, col) &&
                         qrCode.isDark(row + 3, col) &&
                         qrCode.isDark(row + 4, col) &&
                        !qrCode.isDark(row + 5, col) &&
                         qrCode.isDark(row + 6, col) ) {
                    lostPoint += 40;
                }
            }
        }

// LEVEL4
        
        var darkCount = 0;

for (col = 0; col < moduleCount; col++) {
            for (row = 0; row < moduleCount; row++) {
                if (qrCode.isDark(row, col) ) {
                    darkCount++;
                }
            }
        }
        
        var ratio = Math.abs(100 * darkCount / moduleCount / moduleCount - 50) / 5;
        lostPoint += ratio * 10;

return lostPoint;       
    }

};

module.exports = QRUtil;

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