tor-browser

qrcode.mjs (51921B)

---

//---------------------------------------------------------------------
//
// QR Code Generator for JavaScript
//
// Copyright (c) 2009 Kazuhiko Arase
//
// URL: http://www.d-project.com/
//
// Licensed under the MIT license:
//  http://www.opensource.org/licenses/mit-license.php
//
// The word 'QR Code' is registered trademark of
// DENSO WAVE INCORPORATED
//  http://www.denso-wave.com/qrcode/faqpatent-e.html
//
//---------------------------------------------------------------------

//---------------------------------------------------------------------
// qrcode
//---------------------------------------------------------------------

/**
* qrcode
* @param typeNumber 1 to 40
* @param errorCorrectionLevel 'L','M','Q','H'
*/
export const qrcode = function(typeNumber, errorCorrectionLevel) {

 const PAD0 = 0xEC;
 const PAD1 = 0x11;

 let _typeNumber = typeNumber;
 const _errorCorrectionLevel = QRErrorCorrectionLevel[errorCorrectionLevel];
 let _modules = null;
 let _moduleCount = 0;
 let _dataCache = null;
 const _dataList = [];

 const _this = {};

 const makeImpl = function(test, maskPattern) {

   _moduleCount = _typeNumber * 4 + 17;
   _modules = function(moduleCount) {
     const modules = new Array(moduleCount);
     for (let row = 0; row < moduleCount; row += 1) {
       modules[row] = new Array(moduleCount);
       for (let col = 0; col < moduleCount; col += 1) {
         modules[row][col] = null;
       }
     }
     return modules;
   }(_moduleCount);

   setupPositionProbePattern(0, 0);
   setupPositionProbePattern(_moduleCount - 7, 0);
   setupPositionProbePattern(0, _moduleCount - 7);
   setupPositionAdjustPattern();
   setupTimingPattern();
   setupTypeInfo(test, maskPattern);

   if (_typeNumber >= 7) {
     setupTypeNumber(test);
   }

   if (_dataCache == null) {
     _dataCache = createData(_typeNumber, _errorCorrectionLevel, _dataList);
   }

   mapData(_dataCache, maskPattern);
 };

 const setupPositionProbePattern = function(row, col) {

   for (let r = -1; r <= 7; r += 1) {

     if (row + r <= -1 || _moduleCount <= row + r) continue;

     for (let c = -1; c <= 7; c += 1) {

       if (col + c <= -1 || _moduleCount <= col + c) continue;

       if ( (0 <= r && r <= 6 && (c == 0 || c == 6) )
           || (0 <= c && c <= 6 && (r == 0 || r == 6) )
           || (2 <= r && r <= 4 && 2 <= c && c <= 4) ) {
         _modules[row + r][col + c] = true;
       } else {
         _modules[row + r][col + c] = false;
       }
     }
   }
 };

 const getBestMaskPattern = function() {

   let minLostPoint = 0;
   let pattern = 0;

   for (let i = 0; i < 8; i += 1) {

     makeImpl(true, i);

     const lostPoint = QRUtil.getLostPoint(_this);

     if (i == 0 || minLostPoint > lostPoint) {
       minLostPoint = lostPoint;
       pattern = i;
     }
   }

   return pattern;
 };

 const setupTimingPattern = function() {

   for (let r = 8; r < _moduleCount - 8; r += 1) {
     if (_modules[r][6] != null) {
       continue;
     }
     _modules[r][6] = (r % 2 == 0);
   }

   for (let c = 8; c < _moduleCount - 8; c += 1) {
     if (_modules[6][c] != null) {
       continue;
     }
     _modules[6][c] = (c % 2 == 0);
   }
 };

 const setupPositionAdjustPattern = function() {

   const pos = QRUtil.getPatternPosition(_typeNumber);

   for (let i = 0; i < pos.length; i += 1) {

     for (let j = 0; j < pos.length; j += 1) {

       const row = pos[i];
       const col = pos[j];

       if (_modules[row][col] != null) {
         continue;
       }

       for (let r = -2; r <= 2; r += 1) {

         for (let c = -2; c <= 2; c += 1) {

           if (r == -2 || r == 2 || c == -2 || c == 2
               || (r == 0 && c == 0) ) {
             _modules[row + r][col + c] = true;
           } else {
             _modules[row + r][col + c] = false;
           }
         }
       }
     }
   }
 };

 const setupTypeNumber = function(test) {

   const bits = QRUtil.getBCHTypeNumber(_typeNumber);

   for (let i = 0; i < 18; i += 1) {
     const mod = (!test && ( (bits >> i) & 1) == 1);
     _modules[Math.floor(i / 3)][i % 3 + _moduleCount - 8 - 3] = mod;
   }

   for (let i = 0; i < 18; i += 1) {
     const mod = (!test && ( (bits >> i) & 1) == 1);
     _modules[i % 3 + _moduleCount - 8 - 3][Math.floor(i / 3)] = mod;
   }
 };

 const setupTypeInfo = function(test, maskPattern) {

   const data = (_errorCorrectionLevel << 3) | maskPattern;
   const bits = QRUtil.getBCHTypeInfo(data);

   // vertical
   for (let i = 0; i < 15; i += 1) {

     const mod = (!test && ( (bits >> i) & 1) == 1);

     if (i < 6) {
       _modules[i][8] = mod;
     } else if (i < 8) {
       _modules[i + 1][8] = mod;
     } else {
       _modules[_moduleCount - 15 + i][8] = mod;
     }
   }

   // horizontal
   for (let i = 0; i < 15; i += 1) {

     const mod = (!test && ( (bits >> i) & 1) == 1);

     if (i < 8) {
       _modules[8][_moduleCount - i - 1] = mod;
     } else if (i < 9) {
       _modules[8][15 - i - 1 + 1] = mod;
     } else {
       _modules[8][15 - i - 1] = mod;
     }
   }

   // fixed module
   _modules[_moduleCount - 8][8] = (!test);
 };

 const mapData = function(data, maskPattern) {

   let inc = -1;
   let row = _moduleCount - 1;
   let bitIndex = 7;
   let byteIndex = 0;
   const maskFunc = QRUtil.getMaskFunction(maskPattern);

   for (let col = _moduleCount - 1; col > 0; col -= 2) {

     if (col == 6) col -= 1;

     while (true) {

       for (let c = 0; c < 2; c += 1) {

         if (_modules[row][col - c] == null) {

           let dark = false;

           if (byteIndex < data.length) {
             dark = ( ( (data[byteIndex] >>> bitIndex) & 1) == 1);
           }

           const mask = maskFunc(row, col - c);

           if (mask) {
             dark = !dark;
           }

           _modules[row][col - c] = dark;
           bitIndex -= 1;

           if (bitIndex == -1) {
             byteIndex += 1;
             bitIndex = 7;
           }
         }
       }

       row += inc;

       if (row < 0 || _moduleCount <= row) {
         row -= inc;
         inc = -inc;
         break;
       }
     }
   }
 };

 const createBytes = function(buffer, rsBlocks) {

   let offset = 0;

   let maxDcCount = 0;
   let maxEcCount = 0;

   const dcdata = new Array(rsBlocks.length);
   const ecdata = new Array(rsBlocks.length);

   for (let r = 0; r < rsBlocks.length; r += 1) {

     const dcCount = rsBlocks[r].dataCount;
     const ecCount = rsBlocks[r].totalCount - dcCount;

     maxDcCount = Math.max(maxDcCount, dcCount);
     maxEcCount = Math.max(maxEcCount, ecCount);

     dcdata[r] = new Array(dcCount);

     for (let i = 0; i < dcdata[r].length; i += 1) {
       dcdata[r][i] = 0xff & buffer.getBuffer()[i + offset];
     }
     offset += dcCount;

     const rsPoly = QRUtil.getErrorCorrectPolynomial(ecCount);
     const rawPoly = qrPolynomial(dcdata[r], rsPoly.getLength() - 1);

     const modPoly = rawPoly.mod(rsPoly);
     ecdata[r] = new Array(rsPoly.getLength() - 1);
     for (let i = 0; i < ecdata[r].length; i += 1) {
       const modIndex = i + modPoly.getLength() - ecdata[r].length;
       ecdata[r][i] = (modIndex >= 0)? modPoly.getAt(modIndex) : 0;
     }
   }

   let totalCodeCount = 0;
   for (let i = 0; i < rsBlocks.length; i += 1) {
     totalCodeCount += rsBlocks[i].totalCount;
   }

   const data = new Array(totalCodeCount);
   let index = 0;

   for (let i = 0; i < maxDcCount; i += 1) {
     for (let r = 0; r < rsBlocks.length; r += 1) {
       if (i < dcdata[r].length) {
         data[index] = dcdata[r][i];
         index += 1;
       }
     }
   }

   for (let i = 0; i < maxEcCount; i += 1) {
     for (let r = 0; r < rsBlocks.length; r += 1) {
       if (i < ecdata[r].length) {
         data[index] = ecdata[r][i];
         index += 1;
       }
     }
   }

   return data;
 };

 const createData = function(typeNumber, errorCorrectionLevel, dataList) {

   const rsBlocks = QRRSBlock.getRSBlocks(typeNumber, errorCorrectionLevel);

   const buffer = qrBitBuffer();

   for (let i = 0; i < dataList.length; i += 1) {
     const data = dataList[i];
     buffer.put(data.getMode(), 4);
     buffer.put(data.getLength(), QRUtil.getLengthInBits(data.getMode(), typeNumber) );
     data.write(buffer);
   }

   // calc num max data.
   let totalDataCount = 0;
   for (let i = 0; i < rsBlocks.length; i += 1) {
     totalDataCount += rsBlocks[i].dataCount;
   }

   if (buffer.getLengthInBits() > totalDataCount * 8) {
     throw 'code length overflow. ('
       + buffer.getLengthInBits()
       + '>'
       + totalDataCount * 8
       + ')';
   }

   // end code
   if (buffer.getLengthInBits() + 4 <= totalDataCount * 8) {
     buffer.put(0, 4);
   }

   // padding
   while (buffer.getLengthInBits() % 8 != 0) {
     buffer.putBit(false);
   }

   // padding
   while (true) {

     if (buffer.getLengthInBits() >= totalDataCount * 8) {
       break;
     }
     buffer.put(PAD0, 8);

     if (buffer.getLengthInBits() >= totalDataCount * 8) {
       break;
     }
     buffer.put(PAD1, 8);
   }

   return createBytes(buffer, rsBlocks);
 };

 _this.addData = function(data, mode) {

   mode = mode || 'Byte';

   let newData = null;

   switch(mode) {
   case 'Numeric' :
     newData = qrNumber(data);
     break;
   case 'Alphanumeric' :
     newData = qrAlphaNum(data);
     break;
   case 'Byte' :
     newData = qr8BitByte(data);
     break;
   case 'Kanji' :
     newData = qrKanji(data);
     break;
   default :
     throw 'mode:' + mode;
   }

   _dataList.push(newData);
   _dataCache = null;
 };

 _this.isDark = function(row, col) {
   if (row < 0 || _moduleCount <= row || col < 0 || _moduleCount <= col) {
     throw row + ',' + col;
   }
   return _modules[row][col];
 };

 _this.getModuleCount = function() {
   return _moduleCount;
 };

 _this.make = function() {
   if (_typeNumber < 1) {
     let typeNumber = 1;

     for (; typeNumber < 40; typeNumber++) {
       const rsBlocks = QRRSBlock.getRSBlocks(typeNumber, _errorCorrectionLevel);
       const buffer = qrBitBuffer();

       for (let i = 0; i < _dataList.length; i++) {
         const data = _dataList[i];
         buffer.put(data.getMode(), 4);
         buffer.put(data.getLength(), QRUtil.getLengthInBits(data.getMode(), typeNumber) );
         data.write(buffer);
       }

       let totalDataCount = 0;
       for (let i = 0; i < rsBlocks.length; i++) {
         totalDataCount += rsBlocks[i].dataCount;
       }

       if (buffer.getLengthInBits() <= totalDataCount * 8) {
         break;
       }
     }

     _typeNumber = typeNumber;
   }

   makeImpl(false, getBestMaskPattern() );
 };

 _this.createTableTag = function(cellSize, margin) {

   cellSize = cellSize || 2;
   margin = (typeof margin == 'undefined')? cellSize * 4 : margin;

   let qrHtml = '';

   qrHtml += '<table style="';
   qrHtml += ' border-width: 0px; border-style: none;';
   qrHtml += ' border-collapse: collapse;';
   qrHtml += ' padding: 0px; margin: ' + margin + 'px;';
   qrHtml += '">';
   qrHtml += '<tbody>';

   for (let r = 0; r < _this.getModuleCount(); r += 1) {

     qrHtml += '<tr>';

     for (let c = 0; c < _this.getModuleCount(); c += 1) {
       qrHtml += '<td style="';
       qrHtml += ' border-width: 0px; border-style: none;';
       qrHtml += ' border-collapse: collapse;';
       qrHtml += ' padding: 0px; margin: 0px;';
       qrHtml += ' width: ' + cellSize + 'px;';
       qrHtml += ' height: ' + cellSize + 'px;';
       qrHtml += ' background-color: ';
       qrHtml += _this.isDark(r, c)? '#000000' : '#ffffff';
       qrHtml += ';';
       qrHtml += '"/>';
     }

     qrHtml += '</tr>';
   }

   qrHtml += '</tbody>';
   qrHtml += '</table>';

   return qrHtml;
 };

 _this.createSvgTag = function(cellSize, margin, alt, title) {

   let opts = {};
   if (typeof arguments[0] == 'object') {
     // Called by options.
     opts = arguments[0];
     // overwrite cellSize and margin.
     cellSize = opts.cellSize;
     margin = opts.margin;
     alt = opts.alt;
     title = opts.title;
   }

   cellSize = cellSize || 2;
   margin = (typeof margin == 'undefined')? cellSize * 4 : margin;

   // Compose alt property surrogate
   alt = (typeof alt === 'string') ? {text: alt} : alt || {};
   alt.text = alt.text || null;
   alt.id = (alt.text) ? alt.id || 'qrcode-description' : null;

   // Compose title property surrogate
   title = (typeof title === 'string') ? {text: title} : title || {};
   title.text = title.text || null;
   title.id = (title.text) ? title.id || 'qrcode-title' : null;

   const size = _this.getModuleCount() * cellSize + margin * 2;
   let c, mc, r, mr, qrSvg='', rect;

   rect = 'l' + cellSize + ',0 0,' + cellSize +
     ' -' + cellSize + ',0 0,-' + cellSize + 'z ';

   qrSvg += '<svg version="1.1" xmlns="http://www.w3.org/2000/svg"';
   qrSvg += !opts.scalable ? ' width="' + size + 'px" height="' + size + 'px"' : '';
   qrSvg += ' viewBox="0 0 ' + size + ' ' + size + '" ';
   qrSvg += ' preserveAspectRatio="xMinYMin meet"';
   qrSvg += (title.text || alt.text) ? ' role="img" aria-labelledby="' +
       escapeXml([title.id, alt.id].join(' ').trim() ) + '"' : '';
   qrSvg += '>';
   qrSvg += (title.text) ? '<title id="' + escapeXml(title.id) + '">' +
       escapeXml(title.text) + '</title>' : '';
   qrSvg += (alt.text) ? '<description id="' + escapeXml(alt.id) + '">' +
       escapeXml(alt.text) + '</description>' : '';
   qrSvg += '<rect width="100%" height="100%" fill="white" cx="0" cy="0"/>';
   qrSvg += '<path d="';

   for (r = 0; r < _this.getModuleCount(); r += 1) {
     mr = r * cellSize + margin;
     for (c = 0; c < _this.getModuleCount(); c += 1) {
       if (_this.isDark(r, c) ) {
         mc = c*cellSize+margin;
         qrSvg += 'M' + mc + ',' + mr + rect;
       }
     }
   }

   qrSvg += '" stroke="transparent" fill="black"/>';
   qrSvg += '</svg>';

   return qrSvg;
 };

 _this.createDataURL = function(cellSize, margin) {

   cellSize = cellSize || 2;
   margin = (typeof margin == 'undefined')? cellSize * 4 : margin;

   const size = _this.getModuleCount() * cellSize + margin * 2;
   const min = margin;
   const max = size - margin;

   return createDataURL(size, size, function(x, y) {
     if (min <= x && x < max && min <= y && y < max) {
       const c = Math.floor( (x - min) / cellSize);
       const r = Math.floor( (y - min) / cellSize);
       return _this.isDark(r, c)? 0 : 1;
     } else {
       return 1;
     }
   } );
 };

 _this.createImgTag = function(cellSize, margin, alt) {

   cellSize = cellSize || 2;
   margin = (typeof margin == 'undefined')? cellSize * 4 : margin;

   const size = _this.getModuleCount() * cellSize + margin * 2;

   let img = '';
   img += '<img';
   img += '\u0020src="';
   img += _this.createDataURL(cellSize, margin);
   img += '"';
   img += '\u0020width="';
   img += size;
   img += '"';
   img += '\u0020height="';
   img += size;
   img += '"';
   if (alt) {
     img += '\u0020alt="';
     img += escapeXml(alt);
     img += '"';
   }
   img += '/>';

   return img;
 };

 const escapeXml = function(s) {
   let escaped = '';
   for (let i = 0; i < s.length; i += 1) {
     const c = s.charAt(i);
     switch(c) {
     case '<': escaped += '&lt;'; break;
     case '>': escaped += '&gt;'; break;
     case '&': escaped += '&amp;'; break;
     case '"': escaped += '&quot;'; break;
     default : escaped += c; break;
     }
   }
   return escaped;
 };

 const _createHalfASCII = function(margin) {
   const cellSize = 1;
   margin = (typeof margin == 'undefined')? cellSize * 2 : margin;

   const size = _this.getModuleCount() * cellSize + margin * 2;
   const min = margin;
   const max = size - margin;

   let y, x, r1, r2, p;

   const blocks = {
     '██': '█',
     '█ ': '▀',
     ' █': '▄',
     '  ': ' '
   };

   const blocksLastLineNoMargin = {
     '██': '▀',
     '█ ': '▀',
     ' █': ' ',
     '  ': ' '
   };

   let ascii = '';
   for (y = 0; y < size; y += 2) {
     r1 = Math.floor((y - min) / cellSize);
     r2 = Math.floor((y + 1 - min) / cellSize);
     for (x = 0; x < size; x += 1) {
       p = '█';

       if (min <= x && x < max && min <= y && y < max && _this.isDark(r1, Math.floor((x - min) / cellSize))) {
         p = ' ';
       }

       if (min <= x && x < max && min <= y+1 && y+1 < max && _this.isDark(r2, Math.floor((x - min) / cellSize))) {
         p += ' ';
       }
       else {
         p += '█';
       }

       // Output 2 characters per pixel, to create full square. 1 character per pixels gives only half width of square.
       ascii += (margin < 1 && y+1 >= max) ? blocksLastLineNoMargin[p] : blocks[p];
     }

     ascii += '\n';
   }

   if (size % 2 && margin > 0) {
     return ascii.substring(0, ascii.length - size - 1) + Array(size+1).join('▀');
   }

   return ascii.substring(0, ascii.length-1);
 };

 _this.createASCII = function(cellSize, margin) {
   cellSize = cellSize || 1;

   if (cellSize < 2) {
     return _createHalfASCII(margin);
   }

   cellSize -= 1;
   margin = (typeof margin == 'undefined')? cellSize * 2 : margin;

   const size = _this.getModuleCount() * cellSize + margin * 2;
   const min = margin;
   const max = size - margin;

   let y, x, r, p;

   const white = Array(cellSize+1).join('██');
   const black = Array(cellSize+1).join('  ');

   let ascii = '';
   let line = '';
   for (y = 0; y < size; y += 1) {
     r = Math.floor( (y - min) / cellSize);
     line = '';
     for (x = 0; x < size; x += 1) {
       p = 1;

       if (min <= x && x < max && min <= y && y < max && _this.isDark(r, Math.floor((x - min) / cellSize))) {
         p = 0;
       }

       // Output 2 characters per pixel, to create full square. 1 character per pixels gives only half width of square.
       line += p ? white : black;
     }

     for (r = 0; r < cellSize; r += 1) {
       ascii += line + '\n';
     }
   }

   return ascii.substring(0, ascii.length-1);
 };

 _this.renderTo2dContext = function(context, cellSize) {
   cellSize = cellSize || 2;
   const length = _this.getModuleCount();
   for (let row = 0; row < length; row++) {
     for (let col = 0; col < length; col++) {
       context.fillStyle = _this.isDark(row, col) ? 'black' : 'white';
       context.fillRect(col * cellSize, row * cellSize, cellSize, cellSize);
     }
   }
 }

 return _this;
};

//---------------------------------------------------------------------
// qrcode.stringToBytes
//---------------------------------------------------------------------

qrcode.stringToBytes = function(s) {
 const bytes = [];
 for (let i = 0; i < s.length; i += 1) {
   const c = s.charCodeAt(i);
   bytes.push(c & 0xff);
 }
 return bytes;
};

//---------------------------------------------------------------------
// qrcode.createStringToBytes
//---------------------------------------------------------------------

/**
* @param unicodeData base64 string of byte array.
* [16bit Unicode],[16bit Bytes], ...
* @param numChars
*/
qrcode.createStringToBytes = function(unicodeData, numChars) {

 // create conversion map.

 const unicodeMap = function() {

   const bin = base64DecodeInputStream(unicodeData);
   const read = function() {
     const b = bin.read();
     if (b == -1) throw 'eof';
     return b;
   };

   let count = 0;
   const unicodeMap = {};
   while (true) {
     const b0 = bin.read();
     if (b0 == -1) break;
     const b1 = read();
     const b2 = read();
     const b3 = read();
     const k = String.fromCharCode( (b0 << 8) | b1);
     const v = (b2 << 8) | b3;
     unicodeMap[k] = v;
     count += 1;
   }
   if (count != numChars) {
     throw count + ' != ' + numChars;
   }

   return unicodeMap;
 }();

 const unknownChar = '?'.charCodeAt(0);

 return function(s) {
   const bytes = [];
   for (let i = 0; i < s.length; i += 1) {
     const c = s.charCodeAt(i);
     if (c < 128) {
       bytes.push(c);
     } else {
       const b = unicodeMap[s.charAt(i)];
       if (typeof b == 'number') {
         if ( (b & 0xff) == b) {
           // 1byte
           bytes.push(b);
         } else {
           // 2bytes
           bytes.push(b >>> 8);
           bytes.push(b & 0xff);
         }
       } else {
         bytes.push(unknownChar);
       }
     }
   }
   return bytes;
 };
};

//---------------------------------------------------------------------
// QRMode
//---------------------------------------------------------------------

const QRMode = {
 MODE_NUMBER :    1 << 0,
 MODE_ALPHA_NUM : 1 << 1,
 MODE_8BIT_BYTE : 1 << 2,
 MODE_KANJI :     1 << 3
};

//---------------------------------------------------------------------
// QRErrorCorrectionLevel
//---------------------------------------------------------------------

export const QRErrorCorrectionLevel = {
 L : 1,
 M : 0,
 Q : 3,
 H : 2
};

//---------------------------------------------------------------------
// QRMaskPattern
//---------------------------------------------------------------------

const QRMaskPattern = {
 PATTERN000 : 0,
 PATTERN001 : 1,
 PATTERN010 : 2,
 PATTERN011 : 3,
 PATTERN100 : 4,
 PATTERN101 : 5,
 PATTERN110 : 6,
 PATTERN111 : 7
};

//---------------------------------------------------------------------
// QRUtil
//---------------------------------------------------------------------

const QRUtil = function() {

 const 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]
 ];
 const G15 = (1 << 10) | (1 << 8) | (1 << 5) | (1 << 4) | (1 << 2) | (1 << 1) | (1 << 0);
 const G18 = (1 << 12) | (1 << 11) | (1 << 10) | (1 << 9) | (1 << 8) | (1 << 5) | (1 << 2) | (1 << 0);
 const G15_MASK = (1 << 14) | (1 << 12) | (1 << 10) | (1 << 4) | (1 << 1);

 const _this = {};

 const getBCHDigit = function(data) {
   let digit = 0;
   while (data != 0) {
     digit += 1;
     data >>>= 1;
   }
   return digit;
 };

 _this.getBCHTypeInfo = function(data) {
   let d = data << 10;
   while (getBCHDigit(d) - getBCHDigit(G15) >= 0) {
     d ^= (G15 << (getBCHDigit(d) - getBCHDigit(G15) ) );
   }
   return ( (data << 10) | d) ^ G15_MASK;
 };

 _this.getBCHTypeNumber = function(data) {
   let d = data << 12;
   while (getBCHDigit(d) - getBCHDigit(G18) >= 0) {
     d ^= (G18 << (getBCHDigit(d) - getBCHDigit(G18) ) );
   }
   return (data << 12) | d;
 };

 _this.getPatternPosition = function(typeNumber) {
   return PATTERN_POSITION_TABLE[typeNumber - 1];
 };

 _this.getMaskFunction = function(maskPattern) {

   switch (maskPattern) {

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

   default :
     throw 'bad maskPattern:' + maskPattern;
   }
 };

 _this.getErrorCorrectPolynomial = function(errorCorrectLength) {
   let a = qrPolynomial([1], 0);
   for (let i = 0; i < errorCorrectLength; i += 1) {
     a = a.multiply(qrPolynomial([1, QRMath.gexp(i)], 0) );
   }
   return a;
 };

 _this.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 '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 '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 'mode:' + mode;
     }

   } else {
     throw 'type:' + type;
   }
 };

 _this.getLostPoint = function(qrcode) {

   const moduleCount = qrcode.getModuleCount();

   let lostPoint = 0;

   // LEVEL1

   for (let row = 0; row < moduleCount; row += 1) {
     for (let col = 0; col < moduleCount; col += 1) {

       let sameCount = 0;
       const dark = qrcode.isDark(row, col);

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

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

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

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

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

           if (dark == qrcode.isDark(row + r, col + c) ) {
             sameCount += 1;
           }
         }
       }

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

   // LEVEL2

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

   // LEVEL3

   for (let row = 0; row < moduleCount; row += 1) {
     for (let col = 0; col < moduleCount - 6; col += 1) {
       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 (let col = 0; col < moduleCount; col += 1) {
     for (let row = 0; row < moduleCount - 6; row += 1) {
       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

   let darkCount = 0;

   for (let col = 0; col < moduleCount; col += 1) {
     for (let row = 0; row < moduleCount; row += 1) {
       if (qrcode.isDark(row, col) ) {
         darkCount += 1;
       }
     }
   }

   const ratio = Math.abs(100 * darkCount / moduleCount / moduleCount - 50) / 5;
   lostPoint += ratio * 10;

   return lostPoint;
 };

 return _this;
}();

//---------------------------------------------------------------------
// QRMath
//---------------------------------------------------------------------

const QRMath = function() {

 const EXP_TABLE = new Array(256);
 const LOG_TABLE = new Array(256);

 // initialize tables
 for (let i = 0; i < 8; i += 1) {
   EXP_TABLE[i] = 1 << i;
 }
 for (let i = 8; i < 256; i += 1) {
   EXP_TABLE[i] = EXP_TABLE[i - 4]
     ^ EXP_TABLE[i - 5]
     ^ EXP_TABLE[i - 6]
     ^ EXP_TABLE[i - 8];
 }
 for (let i = 0; i < 255; i += 1) {
   LOG_TABLE[EXP_TABLE[i] ] = i;
 }

 const _this = {};

 _this.glog = function(n) {

   if (n < 1) {
     throw 'glog(' + n + ')';
   }

   return LOG_TABLE[n];
 };

 _this.gexp = function(n) {

   while (n < 0) {
     n += 255;
   }

   while (n >= 256) {
     n -= 255;
   }

   return EXP_TABLE[n];
 };

 return _this;
}();

//---------------------------------------------------------------------
// qrPolynomial
//---------------------------------------------------------------------

const qrPolynomial = function(num, shift) {

 if (typeof num.length == 'undefined') {
   throw num.length + '/' + shift;
 }

 const _num = function() {
   let offset = 0;
   while (offset < num.length && num[offset] == 0) {
     offset += 1;
   }
   const _num = new Array(num.length - offset + shift);
   for (let i = 0; i < num.length - offset; i += 1) {
     _num[i] = num[i + offset];
   }
   return _num;
 }();

 const _this = {};

 _this.getAt = function(index) {
   return _num[index];
 };

 _this.getLength = function() {
   return _num.length;
 };

 _this.multiply = function(e) {

   const num = new Array(_this.getLength() + e.getLength() - 1);

   for (let i = 0; i < _this.getLength(); i += 1) {
     for (let j = 0; j < e.getLength(); j += 1) {
       num[i + j] ^= QRMath.gexp(QRMath.glog(_this.getAt(i) ) + QRMath.glog(e.getAt(j) ) );
     }
   }

   return qrPolynomial(num, 0);
 };

 _this.mod = function(e) {

   if (_this.getLength() - e.getLength() < 0) {
     return _this;
   }

   const ratio = QRMath.glog(_this.getAt(0) ) - QRMath.glog(e.getAt(0) );

   const num = new Array(_this.getLength() );
   for (let i = 0; i < _this.getLength(); i += 1) {
     num[i] = _this.getAt(i);
   }

   for (let i = 0; i < e.getLength(); i += 1) {
     num[i] ^= QRMath.gexp(QRMath.glog(e.getAt(i) ) + ratio);
   }

   // recursive call
   return qrPolynomial(num, 0).mod(e);
 };

 return _this;
};

//---------------------------------------------------------------------
// QRRSBlock
//---------------------------------------------------------------------

export const QRRSBlock = function() {

 const RS_BLOCK_TABLE = [

   // L
   // M
   // Q
   // H

   // 1
   [1, 26, 19],
   [1, 26, 16],
   [1, 26, 13],
   [1, 26, 9],

   // 2
   [1, 44, 34],
   [1, 44, 28],
   [1, 44, 22],
   [1, 44, 16],

   // 3
   [1, 70, 55],
   [1, 70, 44],
   [2, 35, 17],
   [2, 35, 13],

   // 4
   [1, 100, 80],
   [2, 50, 32],
   [2, 50, 24],
   [4, 25, 9],

   // 5
   [1, 134, 108],
   [2, 67, 43],
   [2, 33, 15, 2, 34, 16],
   [2, 33, 11, 2, 34, 12],

   // 6
   [2, 86, 68],
   [4, 43, 27],
   [4, 43, 19],
   [4, 43, 15],

   // 7
   [2, 98, 78],
   [4, 49, 31],
   [2, 32, 14, 4, 33, 15],
   [4, 39, 13, 1, 40, 14],

   // 8
   [2, 121, 97],
   [2, 60, 38, 2, 61, 39],
   [4, 40, 18, 2, 41, 19],
   [4, 40, 14, 2, 41, 15],

   // 9
   [2, 146, 116],
   [3, 58, 36, 2, 59, 37],
   [4, 36, 16, 4, 37, 17],
   [4, 36, 12, 4, 37, 13],

   // 10
   [2, 86, 68, 2, 87, 69],
   [4, 69, 43, 1, 70, 44],
   [6, 43, 19, 2, 44, 20],
   [6, 43, 15, 2, 44, 16],

   // 11
   [4, 101, 81],
   [1, 80, 50, 4, 81, 51],
   [4, 50, 22, 4, 51, 23],
   [3, 36, 12, 8, 37, 13],

   // 12
   [2, 116, 92, 2, 117, 93],
   [6, 58, 36, 2, 59, 37],
   [4, 46, 20, 6, 47, 21],
   [7, 42, 14, 4, 43, 15],

   // 13
   [4, 133, 107],
   [8, 59, 37, 1, 60, 38],
   [8, 44, 20, 4, 45, 21],
   [12, 33, 11, 4, 34, 12],

   // 14
   [3, 145, 115, 1, 146, 116],
   [4, 64, 40, 5, 65, 41],
   [11, 36, 16, 5, 37, 17],
   [11, 36, 12, 5, 37, 13],

   // 15
   [5, 109, 87, 1, 110, 88],
   [5, 65, 41, 5, 66, 42],
   [5, 54, 24, 7, 55, 25],
   [11, 36, 12, 7, 37, 13],

   // 16
   [5, 122, 98, 1, 123, 99],
   [7, 73, 45, 3, 74, 46],
   [15, 43, 19, 2, 44, 20],
   [3, 45, 15, 13, 46, 16],

   // 17
   [1, 135, 107, 5, 136, 108],
   [10, 74, 46, 1, 75, 47],
   [1, 50, 22, 15, 51, 23],
   [2, 42, 14, 17, 43, 15],

   // 18
   [5, 150, 120, 1, 151, 121],
   [9, 69, 43, 4, 70, 44],
   [17, 50, 22, 1, 51, 23],
   [2, 42, 14, 19, 43, 15],

   // 19
   [3, 141, 113, 4, 142, 114],
   [3, 70, 44, 11, 71, 45],
   [17, 47, 21, 4, 48, 22],
   [9, 39, 13, 16, 40, 14],

   // 20
   [3, 135, 107, 5, 136, 108],
   [3, 67, 41, 13, 68, 42],
   [15, 54, 24, 5, 55, 25],
   [15, 43, 15, 10, 44, 16],

   // 21
   [4, 144, 116, 4, 145, 117],
   [17, 68, 42],
   [17, 50, 22, 6, 51, 23],
   [19, 46, 16, 6, 47, 17],

   // 22
   [2, 139, 111, 7, 140, 112],
   [17, 74, 46],
   [7, 54, 24, 16, 55, 25],
   [34, 37, 13],

   // 23
   [4, 151, 121, 5, 152, 122],
   [4, 75, 47, 14, 76, 48],
   [11, 54, 24, 14, 55, 25],
   [16, 45, 15, 14, 46, 16],

   // 24
   [6, 147, 117, 4, 148, 118],
   [6, 73, 45, 14, 74, 46],
   [11, 54, 24, 16, 55, 25],
   [30, 46, 16, 2, 47, 17],

   // 25
   [8, 132, 106, 4, 133, 107],
   [8, 75, 47, 13, 76, 48],
   [7, 54, 24, 22, 55, 25],
   [22, 45, 15, 13, 46, 16],

   // 26
   [10, 142, 114, 2, 143, 115],
   [19, 74, 46, 4, 75, 47],
   [28, 50, 22, 6, 51, 23],
   [33, 46, 16, 4, 47, 17],

   // 27
   [8, 152, 122, 4, 153, 123],
   [22, 73, 45, 3, 74, 46],
   [8, 53, 23, 26, 54, 24],
   [12, 45, 15, 28, 46, 16],

   // 28
   [3, 147, 117, 10, 148, 118],
   [3, 73, 45, 23, 74, 46],
   [4, 54, 24, 31, 55, 25],
   [11, 45, 15, 31, 46, 16],

   // 29
   [7, 146, 116, 7, 147, 117],
   [21, 73, 45, 7, 74, 46],
   [1, 53, 23, 37, 54, 24],
   [19, 45, 15, 26, 46, 16],

   // 30
   [5, 145, 115, 10, 146, 116],
   [19, 75, 47, 10, 76, 48],
   [15, 54, 24, 25, 55, 25],
   [23, 45, 15, 25, 46, 16],

   // 31
   [13, 145, 115, 3, 146, 116],
   [2, 74, 46, 29, 75, 47],
   [42, 54, 24, 1, 55, 25],
   [23, 45, 15, 28, 46, 16],

   // 32
   [17, 145, 115],
   [10, 74, 46, 23, 75, 47],
   [10, 54, 24, 35, 55, 25],
   [19, 45, 15, 35, 46, 16],

   // 33
   [17, 145, 115, 1, 146, 116],
   [14, 74, 46, 21, 75, 47],
   [29, 54, 24, 19, 55, 25],
   [11, 45, 15, 46, 46, 16],

   // 34
   [13, 145, 115, 6, 146, 116],
   [14, 74, 46, 23, 75, 47],
   [44, 54, 24, 7, 55, 25],
   [59, 46, 16, 1, 47, 17],

   // 35
   [12, 151, 121, 7, 152, 122],
   [12, 75, 47, 26, 76, 48],
   [39, 54, 24, 14, 55, 25],
   [22, 45, 15, 41, 46, 16],

   // 36
   [6, 151, 121, 14, 152, 122],
   [6, 75, 47, 34, 76, 48],
   [46, 54, 24, 10, 55, 25],
   [2, 45, 15, 64, 46, 16],

   // 37
   [17, 152, 122, 4, 153, 123],
   [29, 74, 46, 14, 75, 47],
   [49, 54, 24, 10, 55, 25],
   [24, 45, 15, 46, 46, 16],

   // 38
   [4, 152, 122, 18, 153, 123],
   [13, 74, 46, 32, 75, 47],
   [48, 54, 24, 14, 55, 25],
   [42, 45, 15, 32, 46, 16],

   // 39
   [20, 147, 117, 4, 148, 118],
   [40, 75, 47, 7, 76, 48],
   [43, 54, 24, 22, 55, 25],
   [10, 45, 15, 67, 46, 16],

   // 40
   [19, 148, 118, 6, 149, 119],
   [18, 75, 47, 31, 76, 48],
   [34, 54, 24, 34, 55, 25],
   [20, 45, 15, 61, 46, 16]
 ];

 const qrRSBlock = function(totalCount, dataCount) {
   const _this = {};
   _this.totalCount = totalCount;
   _this.dataCount = dataCount;
   return _this;
 };

 const _this = {};

 const getRsBlockTable = function(typeNumber, errorCorrectionLevel) {

   switch(errorCorrectionLevel) {
   case QRErrorCorrectionLevel.L :
     return RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 0];
   case QRErrorCorrectionLevel.M :
     return RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 1];
   case QRErrorCorrectionLevel.Q :
     return RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 2];
   case QRErrorCorrectionLevel.H :
     return RS_BLOCK_TABLE[(typeNumber - 1) * 4 + 3];
   default :
     return undefined;
   }
 };

 _this.getRSBlocks = function(typeNumber, errorCorrectionLevel) {

   const rsBlock = getRsBlockTable(typeNumber, errorCorrectionLevel);

   if (typeof rsBlock == 'undefined') {
     throw 'bad rs block @ typeNumber:' + typeNumber +
         '/errorCorrectionLevel:' + errorCorrectionLevel;
   }

   const length = rsBlock.length / 3;

   const list = [];

   for (let i = 0; i < length; i += 1) {

     const count = rsBlock[i * 3 + 0];
     const totalCount = rsBlock[i * 3 + 1];
     const dataCount = rsBlock[i * 3 + 2];

     for (let j = 0; j < count; j += 1) {
       list.push(qrRSBlock(totalCount, dataCount) );
     }
   }

   return list;
 };

 return _this;
}();

//---------------------------------------------------------------------
// qrBitBuffer
//---------------------------------------------------------------------

const qrBitBuffer = function() {

 const _buffer = [];
 let _length = 0;

 const _this = {};

 _this.getBuffer = function() {
   return _buffer;
 };

 _this.getAt = function(index) {
   const bufIndex = Math.floor(index / 8);
   return ( (_buffer[bufIndex] >>> (7 - index % 8) ) & 1) == 1;
 };

 _this.put = function(num, length) {
   for (let i = 0; i < length; i += 1) {
     _this.putBit( ( (num >>> (length - i - 1) ) & 1) == 1);
   }
 };

 _this.getLengthInBits = function() {
   return _length;
 };

 _this.putBit = function(bit) {

   const bufIndex = Math.floor(_length / 8);
   if (_buffer.length <= bufIndex) {
     _buffer.push(0);
   }

   if (bit) {
     _buffer[bufIndex] |= (0x80 >>> (_length % 8) );
   }

   _length += 1;
 };

 return _this;
};

//---------------------------------------------------------------------
// qrNumber
//---------------------------------------------------------------------

const qrNumber = function(data) {

 const _mode = QRMode.MODE_NUMBER;
 const _data = data;

 const _this = {};

 _this.getMode = function() {
   return _mode;
 };

 _this.getLength = function(buffer) {
   return _data.length;
 };

 _this.write = function(buffer) {

   const data = _data;

   let i = 0;

   while (i + 2 < data.length) {
     buffer.put(strToNum(data.substring(i, i + 3) ), 10);
     i += 3;
   }

   if (i < data.length) {
     if (data.length - i == 1) {
       buffer.put(strToNum(data.substring(i, i + 1) ), 4);
     } else if (data.length - i == 2) {
       buffer.put(strToNum(data.substring(i, i + 2) ), 7);
     }
   }
 };

 const strToNum = function(s) {
   let num = 0;
   for (let i = 0; i < s.length; i += 1) {
     num = num * 10 + chatToNum(s.charAt(i) );
   }
   return num;
 };

 const chatToNum = function(c) {
   if ('0' <= c && c <= '9') {
     return c.charCodeAt(0) - '0'.charCodeAt(0);
   }
   throw 'illegal char :' + c;
 };

 return _this;
};

//---------------------------------------------------------------------
// qrAlphaNum
//---------------------------------------------------------------------

const qrAlphaNum = function(data) {

 const _mode = QRMode.MODE_ALPHA_NUM;
 const _data = data;

 const _this = {};

 _this.getMode = function() {
   return _mode;
 };

 _this.getLength = function(buffer) {
   return _data.length;
 };

 _this.write = function(buffer) {

   const s = _data;

   let i = 0;

   while (i + 1 < s.length) {
     buffer.put(
       getCode(s.charAt(i) ) * 45 +
       getCode(s.charAt(i + 1) ), 11);
     i += 2;
   }

   if (i < s.length) {
     buffer.put(getCode(s.charAt(i) ), 6);
   }
 };

 const getCode = function(c) {

   if ('0' <= c && c <= '9') {
     return c.charCodeAt(0) - '0'.charCodeAt(0);
   } else if ('A' <= c && c <= 'Z') {
     return c.charCodeAt(0) - 'A'.charCodeAt(0) + 10;
   } else {
     switch (c) {
     case '\u0020' : return 36;
     case '$' : return 37;
     case '%' : return 38;
     case '*' : return 39;
     case '+' : return 40;
     case '-' : return 41;
     case '.' : return 42;
     case '/' : return 43;
     case ':' : return 44;
     default :
       throw 'illegal char :' + c;
     }
   }
 };

 return _this;
};

//---------------------------------------------------------------------
// qr8BitByte
//---------------------------------------------------------------------

const qr8BitByte = function(data) {

 const _mode = QRMode.MODE_8BIT_BYTE;
 const _data = data;
 const _bytes = qrcode.stringToBytes(data);

 const _this = {};

 _this.getMode = function() {
   return _mode;
 };

 _this.getLength = function(buffer) {
   return _bytes.length;
 };

 _this.write = function(buffer) {
   for (let i = 0; i < _bytes.length; i += 1) {
     buffer.put(_bytes[i], 8);
   }
 };

 return _this;
};

//---------------------------------------------------------------------
// qrKanji
//---------------------------------------------------------------------

const qrKanji = function(data) {

 const _mode = QRMode.MODE_KANJI;
 const _data = data;

 const stringToBytes = qrcode.stringToBytes;
 !function(c, code) {
   // self test for sjis support.
   const test = stringToBytes(c);
   if (test.length != 2 || ( (test[0] << 8) | test[1]) != code) {
     throw 'sjis not supported.';
   }
 }('\u53cb', 0x9746);

 const _bytes = stringToBytes(data);

 const _this = {};

 _this.getMode = function() {
   return _mode;
 };

 _this.getLength = function(buffer) {
   return ~~(_bytes.length / 2);
 };

 _this.write = function(buffer) {

   const data = _bytes;

   let i = 0;

   while (i + 1 < data.length) {

     let c = ( (0xff & data[i]) << 8) | (0xff & data[i + 1]);

     if (0x8140 <= c && c <= 0x9FFC) {
       c -= 0x8140;
     } else if (0xE040 <= c && c <= 0xEBBF) {
       c -= 0xC140;
     } else {
       throw 'illegal char at ' + (i + 1) + '/' + c;
     }

     c = ( (c >>> 8) & 0xff) * 0xC0 + (c & 0xff);

     buffer.put(c, 13);

     i += 2;
   }

   if (i < data.length) {
     throw 'illegal char at ' + (i + 1);
   }
 };

 return _this;
};

//=====================================================================
// GIF Support etc.
//

//---------------------------------------------------------------------
// byteArrayOutputStream
//---------------------------------------------------------------------

const byteArrayOutputStream = function() {

 const _bytes = [];

 const _this = {};

 _this.writeByte = function(b) {
   _bytes.push(b & 0xff);
 };

 _this.writeShort = function(i) {
   _this.writeByte(i);
   _this.writeByte(i >>> 8);
 };

 _this.writeBytes = function(b, off, len) {
   off = off || 0;
   len = len || b.length;
   for (let i = 0; i < len; i += 1) {
     _this.writeByte(b[i + off]);
   }
 };

 _this.writeString = function(s) {
   for (let i = 0; i < s.length; i += 1) {
     _this.writeByte(s.charCodeAt(i) );
   }
 };

 _this.toByteArray = function() {
   return _bytes;
 };

 _this.toString = function() {
   let s = '';
   s += '[';
   for (let i = 0; i < _bytes.length; i += 1) {
     if (i > 0) {
       s += ',';
     }
     s += _bytes[i];
   }
   s += ']';
   return s;
 };

 return _this;
};

//---------------------------------------------------------------------
// base64EncodeOutputStream
//---------------------------------------------------------------------

const base64EncodeOutputStream = function() {

 let _buffer = 0;
 let _buflen = 0;
 let _length = 0;
 let _base64 = '';

 const _this = {};

 const writeEncoded = function(b) {
   _base64 += String.fromCharCode(encode(b & 0x3f) );
 };

 const encode = function(n) {
   if (n < 0) {
     throw 'n:' + n;
   } else if (n < 26) {
     return 0x41 + n;
   } else if (n < 52) {
     return 0x61 + (n - 26);
   } else if (n < 62) {
     return 0x30 + (n - 52);
   } else if (n == 62) {
     return 0x2b;
   } else if (n == 63) {
     return 0x2f;
   } else {
     throw 'n:' + n;
   }
 };

 _this.writeByte = function(n) {

   _buffer = (_buffer << 8) | (n & 0xff);
   _buflen += 8;
   _length += 1;

   while (_buflen >= 6) {
     writeEncoded(_buffer >>> (_buflen - 6) );
     _buflen -= 6;
   }
 };

 _this.flush = function() {

   if (_buflen > 0) {
     writeEncoded(_buffer << (6 - _buflen) );
     _buffer = 0;
     _buflen = 0;
   }

   if (_length % 3 != 0) {
     // padding
     const padlen = 3 - _length % 3;
     for (let i = 0; i < padlen; i += 1) {
       _base64 += '=';
     }
   }
 };

 _this.toString = function() {
   return _base64;
 };

 return _this;
};

//---------------------------------------------------------------------
// base64DecodeInputStream
//---------------------------------------------------------------------

const base64DecodeInputStream = function(str) {

 const _str = str;
 let _pos = 0;
 let _buffer = 0;
 let _buflen = 0;

 const _this = {};

 _this.read = function() {

   while (_buflen < 8) {

     if (_pos >= _str.length) {
       if (_buflen == 0) {
         return -1;
       }
       throw 'unexpected end of file./' + _buflen;
     }

     const c = _str.charAt(_pos);
     _pos += 1;

     if (c == '=') {
       _buflen = 0;
       return -1;
     } else if (c.match(/^\s$/) ) {
       // ignore if whitespace.
       continue;
     }

     _buffer = (_buffer << 6) | decode(c.charCodeAt(0) );
     _buflen += 6;
   }

   const n = (_buffer >>> (_buflen - 8) ) & 0xff;
   _buflen -= 8;
   return n;
 };

 const decode = function(c) {
   if (0x41 <= c && c <= 0x5a) {
     return c - 0x41;
   } else if (0x61 <= c && c <= 0x7a) {
     return c - 0x61 + 26;
   } else if (0x30 <= c && c <= 0x39) {
     return c - 0x30 + 52;
   } else if (c == 0x2b) {
     return 62;
   } else if (c == 0x2f) {
     return 63;
   } else {
     throw 'c:' + c;
   }
 };

 return _this;
};

//---------------------------------------------------------------------
// gifImage (B/W)
//---------------------------------------------------------------------

const gifImage = function(width, height) {

 const _width = width;
 const _height = height;
 const _data = new Array(width * height);

 const _this = {};

 _this.setPixel = function(x, y, pixel) {
   _data[y * _width + x] = pixel;
 };

 _this.write = function(out) {

   //---------------------------------
   // GIF Signature

   out.writeString('GIF87a');

   //---------------------------------
   // Screen Descriptor

   out.writeShort(_width);
   out.writeShort(_height);

   out.writeByte(0x80); // 2bit
   out.writeByte(0);
   out.writeByte(0);

   //---------------------------------
   // Global Color Map

   // black
   out.writeByte(0x00);
   out.writeByte(0x00);
   out.writeByte(0x00);

   // white
   out.writeByte(0xff);
   out.writeByte(0xff);
   out.writeByte(0xff);

   //---------------------------------
   // Image Descriptor

   out.writeString(',');
   out.writeShort(0);
   out.writeShort(0);
   out.writeShort(_width);
   out.writeShort(_height);
   out.writeByte(0);

   //---------------------------------
   // Local Color Map

   //---------------------------------
   // Raster Data

   const lzwMinCodeSize = 2;
   const raster = getLZWRaster(lzwMinCodeSize);

   out.writeByte(lzwMinCodeSize);

   let offset = 0;

   while (raster.length - offset > 255) {
     out.writeByte(255);
     out.writeBytes(raster, offset, 255);
     offset += 255;
   }

   out.writeByte(raster.length - offset);
   out.writeBytes(raster, offset, raster.length - offset);
   out.writeByte(0x00);

   //---------------------------------
   // GIF Terminator
   out.writeString(';');
 };

 const bitOutputStream = function(out) {

   const _out = out;
   let _bitLength = 0;
   let _bitBuffer = 0;

   const _this = {};

   _this.write = function(data, length) {

     if ( (data >>> length) != 0) {
       throw 'length over';
     }

     while (_bitLength + length >= 8) {
       _out.writeByte(0xff & ( (data << _bitLength) | _bitBuffer) );
       length -= (8 - _bitLength);
       data >>>= (8 - _bitLength);
       _bitBuffer = 0;
       _bitLength = 0;
     }

     _bitBuffer = (data << _bitLength) | _bitBuffer;
     _bitLength = _bitLength + length;
   };

   _this.flush = function() {
     if (_bitLength > 0) {
       _out.writeByte(_bitBuffer);
     }
   };

   return _this;
 };

 const getLZWRaster = function(lzwMinCodeSize) {

   const clearCode = 1 << lzwMinCodeSize;
   const endCode = (1 << lzwMinCodeSize) + 1;
   let bitLength = lzwMinCodeSize + 1;

   // Setup LZWTable
   const table = lzwTable();

   for (let i = 0; i < clearCode; i += 1) {
     table.add(String.fromCharCode(i) );
   }
   table.add(String.fromCharCode(clearCode) );
   table.add(String.fromCharCode(endCode) );

   const byteOut = byteArrayOutputStream();
   const bitOut = bitOutputStream(byteOut);

   // clear code
   bitOut.write(clearCode, bitLength);

   let dataIndex = 0;

   let s = String.fromCharCode(_data[dataIndex]);
   dataIndex += 1;

   while (dataIndex < _data.length) {

     const c = String.fromCharCode(_data[dataIndex]);
     dataIndex += 1;

     if (table.contains(s + c) ) {

       s = s + c;

     } else {

       bitOut.write(table.indexOf(s), bitLength);

       if (table.size() < 0xfff) {

         if (table.size() == (1 << bitLength) ) {
           bitLength += 1;
         }

         table.add(s + c);
       }

       s = c;
     }
   }

   bitOut.write(table.indexOf(s), bitLength);

   // end code
   bitOut.write(endCode, bitLength);

   bitOut.flush();

   return byteOut.toByteArray();
 };

 const lzwTable = function() {

   const _map = {};
   let _size = 0;

   const _this = {};

   _this.add = function(key) {
     if (_this.contains(key) ) {
       throw 'dup key:' + key;
     }
     _map[key] = _size;
     _size += 1;
   };

   _this.size = function() {
     return _size;
   };

   _this.indexOf = function(key) {
     return _map[key];
   };

   _this.contains = function(key) {
     return typeof _map[key] != 'undefined';
   };

   return _this;
 };

 return _this;
};

const createDataURL = function(width, height, getPixel) {
 const gif = gifImage(width, height);
 for (let y = 0; y < height; y += 1) {
   for (let x = 0; x < width; x += 1) {
     gif.setPixel(x, y, getPixel(x, y) );
   }
 }

 const b = byteArrayOutputStream();
 gif.write(b);

 const base64 = base64EncodeOutputStream();
 const bytes = b.toByteArray();
 for (let i = 0; i < bytes.length; i += 1) {
   base64.writeByte(bytes[i]);
 }
 base64.flush();

 return 'data:image/gif;base64,' + base64;
};

export default qrcode;

export const stringToBytes = qrcode.stringToBytes;