微信小程序生成二维码

1、复制 weapp-qrcode.js

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

// ---------------微信小程序基于base64生成二维码插件修改-------------------
/*
 * @Modified: Pudon
 * @demoURL: https://github.com/Pudon/weapp-qrcode
 * @Date: 2018-09-11 14:00:05
 * @Last Modified by: Pudon
 * @Last Modified time: 2018-09-12 16:33:19
 */
// ---------------------------------------------------------------------

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

    var PAD0 = 0xEC
    var PAD1 = 0x11

    var _typeNumber = typeNumber
    var _errorCorrectLevel = QRErrorCorrectLevel[errorCorrectLevel]
    var _modules = null
    var _moduleCount = 0
    var _dataCache = null
    var _dataList = new Array()

    var _this = {}

    var makeImpl = function(test, maskPattern) {

	_moduleCount = _typeNumber * 4 + 17
	_modules = function(moduleCount) {
	    var modules = new Array(moduleCount)
	    for (var row = 0; row < moduleCount; row += 1) {
		modules[row] = new Array(moduleCount)
		for (var 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, _errorCorrectLevel, _dataList)
	}

	mapData(_dataCache, maskPattern)
    }

    var setupPositionProbePattern = function(row, col) {

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

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

	    for (var 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
		}
	    }
	}
    }

    var getBestMaskPattern = function() {

	var minLostPoint = 0
	var pattern = 0

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

	    makeImpl(true, i)

	    var lostPoint = QRUtil.getLostPoint(_this)

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

	return pattern
    }

    var setupTimingPattern = function() {

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

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

    var setupPositionAdjustPattern = function() {

	var pos = QRUtil.getPatternPosition(_typeNumber)

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

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

		var row = pos[i]
		var col = pos[j]

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

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

		    for (var 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
			}
		    }
		}
	    }
	}
    }

    var setupTypeNumber = function(test) {

	var bits = QRUtil.getBCHTypeNumber(_typeNumber)

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

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

    var setupTypeInfo = function(test, maskPattern) {

	var data = (_errorCorrectLevel << 3) | maskPattern
	var bits = QRUtil.getBCHTypeInfo(data)

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

	    var 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 (var i = 0; i < 15; i += 1) {

	    var 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)
    }

    var mapData = function(data, maskPattern) {

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

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

	    if (col == 6) col -= 1

	    while (true) {

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

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

			var dark = false

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

			var 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
		}
	    }
	}
    }

    var createBytes = function(buffer, rsBlocks) {

	var offset = 0

	var maxDcCount = 0
	var maxEcCount = 0

	var dcdata = new Array(rsBlocks.length)
	var ecdata = new Array(rsBlocks.length)

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

	    var dcCount = rsBlocks[r].dataCount
	    var ecCount = rsBlocks[r].totalCount - dcCount

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

	    dcdata[r] = new Array(dcCount)

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

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

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

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

	var data = new Array(totalCodeCount)
	var index = 0

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

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

	return data
    }

    var createData = function(typeNumber, errorCorrectLevel, dataList) {

	var rsBlocks = QRRSBlock.getRSBlocks(typeNumber, errorCorrectLevel)

	var buffer = qrBitBuffer()

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

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

	if (buffer.getLengthInBits() > totalDataCount * 8) {
	    throw new Error('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) {
	var newData = qr8BitByte(data)
	_dataList.push(newData)
	_dataCache = null
    }

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

    _this.getModuleCount = function() {
	return _moduleCount
    }

    _this.make = function() {
	makeImpl(false, getBestMaskPattern())
    }

    _this.createTableTag = function(cellSize, margin) {

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

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

	    qrHtml += '<tr>'

	    for (var 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.createImgTag = function(cellSize, margin, size) {

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

	var min = margin
	var max = _this.getModuleCount() * cellSize + margin

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

    return _this
}

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

qrcode.stringToBytes = function(s) {
    var bytes = new Array()
    for (var i = 0; i < s.length; i += 1) {
	var 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.

    var unicodeMap = function() {

	var bin = base64DecodeInputStream(unicodeData)
	var read = function() {
	    var b = bin.read()
	    if (b == -1) throw new Error()
	    return b
	}

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

	return unicodeMap
    }()

    var unknownChar = '?'.charCodeAt(0)

    return function(s) {
	var bytes = new Array()
	for (var i = 0; i < s.length; i += 1) {
	    var c = s.charCodeAt(i)
	    if (c < 128) {
		bytes.push(c)
	    } else {
		var 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
// ---------------------------------------------------------------------

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

// ---------------------------------------------------------------------
// QRErrorCorrectLevel
// ---------------------------------------------------------------------

var QRErrorCorrectLevel = {
    L : 1,
    M : 0,
    Q : 3,
    H : 2
}

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

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

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

var QRUtil = function() {

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

    var _this = {}

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

    _this.getBCHTypeInfo = function(data) {
	var 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) {
	var 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 new Error('bad maskPattern:' + maskPattern)
	}
    }

    _this.getErrorCorrectPolynomial = function(errorCorrectLength) {
	var a = qrPolynomial([1], 0)
	for (var 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 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)
	}
    }

    _this.getLostPoint = function(qrcode) {

	var moduleCount = qrcode.getModuleCount()

	var lostPoint = 0

	// LEVEL1

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

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

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

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

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

	var darkCount = 0

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

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

	return lostPoint
    }

    return _this
}()

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

var QRMath = function() {

    var EXP_TABLE = new Array(256)
    var LOG_TABLE = new Array(256)

    // initialize tables
    for (var i = 0; i < 8; i += 1) {
	EXP_TABLE[i] = 1 << i
    }
    for (var 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 (var i = 0; i < 255; i += 1) {
	LOG_TABLE[EXP_TABLE[i] ] = i
    }

    var _this = {}

    _this.glog = function(n) {

	if (n < 1) {
	    throw new Error('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
// ---------------------------------------------------------------------

function qrPolynomial(num, shift) {

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

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

    var _this = {}

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

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

    _this.multiply = function(e) {

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

	for (var i = 0; i < _this.getLength(); i += 1) {
	    for (var 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
	}

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

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

	for (var 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
// ---------------------------------------------------------------------

var QRRSBlock = function() {

    // [1: [L, M, Q, H], ..]
    var RS_BLOCK_TABLE = [[1, 26, 19], [1, 26, 16], [1, 26, 13], [1, 26, 9], [1, 44, 34], [1, 44, 28], [1, 44, 22], [1, 44, 16], [1, 70, 55], [1, 70, 44], [2, 35, 17], [2, 35, 13], [1, 100, 80], [2, 50, 32], [2, 50, 24], [4, 25, 9], [1, 134, 108], [2, 67, 43], [2, 33, 15, 2, 34, 16], [2, 33, 11, 2, 34, 12], [2, 86, 68], [4, 43, 27], [4, 43, 19], [4, 43, 15], [2, 98, 78], [4, 49, 31], [2, 32, 14, 4, 33, 15], [4, 39, 13, 1, 40, 14], [2, 121, 97], [2, 60, 38, 2, 61, 39], [4, 40, 18, 2, 41, 19], [4, 40, 14, 2, 41, 15], [2, 146, 116], [3, 58, 36, 2, 59, 37], [4, 36, 16, 4, 37, 17], [4, 36, 12, 4, 37, 13], [2, 86, 68, 2, 87, 69], [4, 69, 43, 1, 70, 44], [6, 43, 19, 2, 44, 20], [6, 43, 15, 2, 44, 16], [4, 101, 81], [1, 80, 50, 4, 81, 51], [4, 50, 22, 4, 51, 23], [3, 36, 12, 8, 37, 13], [2, 116, 92, 2, 117, 93], [6, 58, 36, 2, 59, 37], [4, 46, 20, 6, 47, 21], [7, 42, 14, 4, 43, 15], [4, 133, 107], [8, 59, 37, 1, 60, 38], [8, 44, 20, 4, 45, 21], [12, 33, 11, 4, 34, 12], [3, 145, 115, 1, 146, 116], [4, 64, 40, 5, 65, 41], [11, 36, 16, 5, 37, 17], [11, 36, 12, 5, 37, 13], [5, 109, 87, 1, 110, 88], [5, 65, 41, 5, 66, 42], [5, 54, 24, 7, 55, 25], [11, 36, 12], [5, 122, 98, 1, 123, 99], [7, 73, 45, 3, 74, 46], [15, 43, 19, 2, 44, 20], [3, 45, 15, 13, 46, 16], [1, 135, 107, 5, 136, 108], [10, 74, 46, 1, 75, 47], [1, 50, 22, 15, 51, 23], [2, 42, 14, 17, 43, 15], [5, 150, 120, 1, 151, 121], [9, 69, 43, 4, 70, 44], [17, 50, 22, 1, 51, 23], [2, 42, 14, 19, 43, 15], [3, 141, 113, 4, 142, 114], [3, 70, 44, 11, 71, 45], [17, 47, 21, 4, 48, 22], [9, 39, 13, 16, 40, 14], [3, 135, 107, 5, 136, 108], [3, 67, 41, 13, 68, 42], [15, 54, 24, 5, 55, 25], [15, 43, 15, 10, 44, 16], [4, 144, 116, 4, 145, 117], [17, 68, 42], [17, 50, 22, 6, 51, 23], [19, 46, 16, 6, 47, 17], [2, 139, 111, 7, 140, 112], [17, 74, 46], [7, 54, 24, 16, 55, 25], [34, 37, 13], [4, 151, 121, 5, 152, 122], [4, 75, 47, 14, 76, 48], [11, 54, 24, 14, 55, 25], [16, 45, 15, 14, 46, 16], [6, 147, 117, 4, 148, 118], [6, 73, 45, 14, 74, 46], [11, 54, 24, 16, 55, 25], [30, 46, 16, 2, 47, 17], [8, 132, 106, 4, 133, 107], [8, 75, 47, 13, 76, 48], [7, 54, 24, 22, 55, 25], [22, 45, 15, 13, 46, 16], [10, 142, 114, 2, 143, 115], [19, 74, 46, 4, 75, 47], [28, 50, 22, 6, 51, 23], [33, 46, 16, 4, 47, 17], [8, 152, 122, 4, 153, 123], [22, 73, 45, 3, 74, 46], [8, 53, 23, 26, 54, 24], [12, 45, 15, 28, 46, 16], [3, 147, 117, 10, 148, 118], [3, 73, 45, 23, 74, 46], [4, 54, 24, 31, 55, 25], [11, 45, 15, 31, 46, 16], [7, 146, 116, 7, 147, 117], [21, 73, 45, 7, 74, 46], [1, 53, 23, 37, 54, 24], [19, 45, 15, 26, 46, 16], [5, 145, 115, 10, 146, 116], [19, 75, 47, 10, 76, 48], [15, 54, 24, 25, 55, 25], [23, 45, 15, 25, 46, 16], [13, 145, 115, 3, 146, 116], [2, 74, 46, 29, 75, 47], [42, 54, 24, 1, 55, 25], [23, 45, 15, 28, 46, 16], [17, 145, 115], [10, 74, 46, 23, 75, 47], [10, 54, 24, 35, 55, 25], [19, 45, 15, 35, 46, 16], [17, 145, 115, 1, 146, 116], [14, 74, 46, 21, 75, 47], [29, 54, 24, 19, 55, 25], [11, 45, 15, 46, 46, 16], [13, 145, 115, 6, 146, 116], [14, 74, 46, 23, 75, 47], [44, 54, 24, 7, 55, 25], [59, 46, 16, 1, 47, 17], [12, 151, 121, 7, 152, 122], [12, 75, 47, 26, 76, 48], [39, 54, 24, 14, 55, 25], [22, 45, 15, 41, 46, 16], [6, 151, 121, 14, 152, 122], [6, 75, 47, 34, 76, 48], [46, 54, 24, 10, 55, 25], [2, 45, 15, 64, 46, 16], [17, 152, 122, 4, 153, 123], [29, 74, 46, 14, 75, 47], [49, 54, 24, 10, 55, 25], [24, 45, 15, 46, 46, 16], [4, 152, 122, 18, 153, 123], [13, 74, 46, 32, 75, 47], [48, 54, 24, 14, 55, 25], [42, 45, 15, 32, 46, 16], [20, 147, 117, 4, 148, 118], [40, 75, 47, 7, 76, 48], [43, 54, 24, 22, 55, 25], [10, 45, 15, 67, 46, 16], [19, 148, 118, 6, 149, 119], [18, 75, 47, 31, 76, 48], [34, 54, 24, 34, 55, 25], [20, 45, 15, 61, 46, 16]]

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

    var _this = {}

    var getRsBlockTable = function(typeNumber, errorCorrectLevel) {

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

    _this.getRSBlocks = function(typeNumber, errorCorrectLevel) {

	var rsBlock = getRsBlockTable(typeNumber, errorCorrectLevel)

	if (typeof rsBlock == 'undefined') {
	    throw new Error('bad rs block @ typeNumber:' + typeNumber +
			    '/errorCorrectLevel:' + errorCorrectLevel)
	}

	var length = rsBlock.length / 3

	var list = new Array()

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

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

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

	return list
    }

    return _this
}()

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

var qrBitBuffer = function() {

    var _buffer = new Array()
    var _length = 0

    var _this = {}

    _this.getBuffer = function() {
	return _buffer
    }

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

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

    _this.getLengthInBits = function() {
	return _length
    }

    _this.putBit = function(bit) {

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

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

	_length += 1
    }

    return _this
}

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

var qr8BitByte = function(data) {

    var _mode = QRMode.MODE_8BIT_BYTE
    var _data = data
    var _parsedData = []

    var _this = {}

    // Added to support UTF-8 Characters
    for (var i = 0, l = _data.length; i < l; i++) {
	var byteArray = []
	var code = _data.charCodeAt(i)

	if (code > 0x10000) {
	    byteArray[0] = 0xF0 | ((code & 0x1C0000) >>> 18)
	    byteArray[1] = 0x80 | ((code & 0x3F000) >>> 12)
	    byteArray[2] = 0x80 | ((code & 0xFC0) >>> 6)
	    byteArray[3] = 0x80 | (code & 0x3F)
	} else if (code > 0x800) {
	    byteArray[0] = 0xE0 | ((code & 0xF000) >>> 12)
	    byteArray[1] = 0x80 | ((code & 0xFC0) >>> 6)
	    byteArray[2] = 0x80 | (code & 0x3F)
	} else if (code > 0x80) {
	    byteArray[0] = 0xC0 | ((code & 0x7C0) >>> 6)
	    byteArray[1] = 0x80 | (code & 0x3F)
	} else {
	    byteArray[0] = code
	}

        // Fix Unicode corruption bug
        _parsedData.push(byteArray)
    }

    _parsedData = Array.prototype.concat.apply([], _parsedData)

    if (_parsedData.length != _data.length) {
	_parsedData.unshift(191)
	_parsedData.unshift(187)
	_parsedData.unshift(239)
    }

    var _bytes = _parsedData

    _this.getMode = function() {
	return _mode
    }

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

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

    return _this
}

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

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

var byteArrayOutputStream = function() {

    var _bytes = new Array()

    var _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 (var i = 0; i < len; i += 1) {
	    _this.writeByte(b[i + off])
	}
    }

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

    _this.toByteArray = function() {
	return _bytes
    }

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

    return _this
}

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

var base64EncodeOutputStream = function() {

    var _buffer = 0
    var _buflen = 0
    var _length = 0
    var _base64 = ''

    var _this = {}

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

    var encode = function(n) {
	if (n < 0) {
	    // error.
	} 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
	}
	throw new Error('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
	    var padlen = 3 - _length % 3
	    for (var i = 0; i < padlen; i += 1) {
		_base64 += '='
	    }
	}
    }

    _this.toString = function() {
	return _base64
    }

    return _this
}

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

var base64DecodeInputStream = function(str) {

    var _str = str
    var _pos = 0
    var _buffer = 0
    var _buflen = 0

    var _this = {}

    _this.read = function() {

	while (_buflen < 8) {

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

	    var 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
	}

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

    var 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 new Error('c:' + c)
	}
    }

    return _this
}

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

var gifImage = function(width, height) {

    var _width = width
    var _height = height
    var _data = new Array(width * height)

    var _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

	var lzwMinCodeSize = 2
	var raster = getLZWRaster(lzwMinCodeSize)

	out.writeByte(lzwMinCodeSize)

	var 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(';')
    }

    var bitOutputStream = function(out) {

	var _out = out
	var _bitLength = 0
	var _bitBuffer = 0

	var _this = {}

	_this.write = function(data, length) {

	    if ((data >>> length) != 0) {
		throw new Error('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
    }

    var getLZWRaster = function(lzwMinCodeSize) {

	var clearCode = 1 << lzwMinCodeSize
	var endCode = (1 << lzwMinCodeSize) + 1
	var bitLength = lzwMinCodeSize + 1

	// Setup LZWTable
	var table = lzwTable()

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

	var byteOut = byteArrayOutputStream()
	var bitOut = bitOutputStream(byteOut)

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

	var dataIndex = 0

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

	while (dataIndex < _data.length) {

	    var 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()
    }

    var lzwTable = function() {

	var _map = {}
	var _size = 0

	var _this = {}

	_this.add = function(key) {
	    if (_this.contains(key)) {
		throw new Error('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
}

var createImgTag = function(width, height, getPixel, alt) {

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

    var b = byteArrayOutputStream()
    gif.write(b)

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

    var img = ''
    img += 'data:image/gif;base64,'
    img += base64

    return img
}

// ---------------------------------------------------------------------
// returns qrcode function.

var drawImg = function(text, options) {
    options = options || {}
    var typeNumber = options.typeNumber || 4
    var errorCorrectLevel = options.errorCorrectLevel || 'M'
    var size = options.size || 500

    var qr

    try {
        qr = qrcode(typeNumber, errorCorrectLevel || 'M')
        qr.addData(text)
        qr.make()
    } catch (e) {
        if (typeNumber >= 40) {
            throw new Error('Text too long to encode')
        } else {
            return drawImg(text, {
                size: size,
                errorCorrectLevel: errorCorrectLevel,
                typeNumber: typeNumber + 1
            })
        }
    }

    // calc cellsize and margin
    var cellsize = parseInt(size / qr.getModuleCount())
    var margin = parseInt((size - qr.getModuleCount() * cellsize) / 2)

    return qr.createImgTag(cellsize, margin, size)
}
module.exports = {
	drawImg: drawImg
}