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QR-Code-generator/javascript/qrcodegen.js

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/*
* QR Code generator library (JavaScript)
*
* Copyright (c) Project Nayuki. (MIT License)
* https://www.nayuki.io/page/qr-code-generator-library
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
"use strict";
/*
* Module "qrcodegen", public members:
* - Class QrCode:
* - Function encodeText(str text, QrCode.Ecc ecl) -> QrCode
* - Function encodeBinary(list<byte> data, QrCode.Ecc ecl) -> QrCode
* - Function encodeSegments(list<QrSegment> segs, QrCode.Ecc ecl,
* int minVersion=1, int maxVersion=40, mask=-1, boostEcl=true) -> QrCode
* - Constants int MIN_VERSION, MAX_VERSION
* - Constructor QrCode(int version, QrCode.Ecc ecl, list<byte> dataCodewords, int mask)
* - Fields int version, size, mask
* - Field QrCode.Ecc errorCorrectionLevel
* - Method getModule(int x, int y) -> bool
* - Method drawCanvas(int scale, int border, HTMLCanvasElement canvas) -> void
* - Method toSvgString(int border) -> str
* - Enum Ecc:
* - Constants LOW, MEDIUM, QUARTILE, HIGH
* - Field int ordinal
* - Class QrSegment:
* - Function makeBytes(list<byte> data) -> QrSegment
* - Function makeNumeric(str data) -> QrSegment
* - Function makeAlphanumeric(str data) -> QrSegment
* - Function makeSegments(str text) -> list<QrSegment>
* - Function makeEci(int assignVal) -> QrSegment
* - Constructor QrSegment(QrSegment.Mode mode, int numChars, list<int> bitData)
* - Field QrSegment.Mode mode
* - Field int numChars
* - Method getData() -> list<int>
* - Constants RegExp NUMERIC_REGEX, ALPHANUMERIC_REGEX
* - Enum Mode:
* - Constants NUMERIC, ALPHANUMERIC, BYTE, KANJI, ECI
*/
var qrcodegen = new function() {
/*---- QR Code symbol class ----*/
/*
* A class that represents a QR Code symbol, which is a type of two-dimension barcode.
* Invented by Denso Wave and described in the ISO/IEC 18004 standard.
* Instances of this class represent an immutable square grid of black and white cells.
* The class provides static factory functions to create a QR Code from text or binary data.
* The class covers the QR Code Model 2 specification, supporting all versions (sizes)
* from 1 to 40, all 4 error correction levels, and 4 character encoding modes.
*
* Ways to create a QR Code object:
* - High level: Take the payload data and call QrCode.encodeText() or QrCode.encodeBinary().
* - Mid level: Custom-make the list of segments and call QrCode.encodeSegments().
* - Low level: Custom-make the array of data codeword bytes (including
* segment headers and final padding, excluding error correction codewords),
* supply the appropriate version number, and call the QrCode() constructor.
* (Note that all ways require supplying the desired error correction level.)
*
* This constructor creates a new QR Code with the given version number,
* error correction level, data codeword bytes, and mask number.
* This is a low-level API that most users should not use directly.
* A mid-level API is the encodeSegments() function.
*/
this.QrCode = function(version, errCorLvl, dataCodewords, mask) {
/*---- Constructor (low level) ----*/
// Check scalar arguments
if (version < MIN_VERSION || version > MAX_VERSION)
throw "Version value out of range";
if (mask < -1 || mask > 7)
throw "Mask value out of range";
if (!(errCorLvl instanceof Ecc))
throw "QrCode.Ecc expected";
var size = version * 4 + 17;
// Initialize both grids to be size*size arrays of Boolean false
var row = [];
for (var i = 0; i < size; i++)
row.push(false);
var modules = []; // Initially all white
var isFunction = [];
for (var i = 0; i < size; i++) {
modules .push(row.slice());
isFunction.push(row.slice());
}
// Compute ECC, draw modules
drawFunctionPatterns();
var allCodewords = addEccAndInterleave(dataCodewords);
drawCodewords(allCodewords);
// Do masking
if (mask == -1) { // Automatically choose best mask
var minPenalty = Infinity;
for (var i = 0; i < 8; i++) {
drawFormatBits(i);
applyMask(i);
var penalty = getPenaltyScore();
if (penalty < minPenalty) {
mask = i;
minPenalty = penalty;
}
applyMask(i); // Undoes the mask due to XOR
}
}
if (mask < 0 || mask > 7)
throw "Assertion error";
drawFormatBits(mask); // Overwrite old format bits
applyMask(mask); // Apply the final choice of mask
isFunction = null;
/*---- Read-only instance properties ----*/
// The version number of this QR Code, which is between 1 and 40 (inclusive).
// This determines the size of this barcode.
Object.defineProperty(this, "version", {value:version});
// The width and height of this QR Code, measured in modules, between
// 21 and 177 (inclusive). This is equal to version * 4 + 17.
Object.defineProperty(this, "size", {value:size});
// The error correction level used in this QR Code.
Object.defineProperty(this, "errorCorrectionLevel", {value:errCorLvl});
// The index of the mask pattern used in this QR Code, which is between 0 and 7 (inclusive).
// Even if a QR Code is created with automatic masking requested (mask = -1),
// the resulting object still has a mask value between 0 and 7.
Object.defineProperty(this, "mask", {value:mask});
/*---- Accessor methods ----*/
// Returns the color of the module (pixel) at the given coordinates, which is false
// for white or true for black. The top left corner has the coordinates (x=0, y=0).
// If the given coordinates are out of bounds, then false (white) is returned.
this.getModule = function(x, y) {
return 0 <= x && x < size && 0 <= y && y < size && modules[y][x];
};
/*---- Public instance methods ----*/
// Draws this QR Code, with the given module scale and border modules, onto the given HTML
// canvas element. The canvas's width and height is resized to (this.size + border * 2) * scale.
// The drawn image is be purely black and white, and fully opaque.
// The scale must be a positive integer and the border must be a non-negative integer.
this.drawCanvas = function(scale, border, canvas) {
if (scale <= 0 || border < 0)
throw "Value out of range";
var width = (size + border * 2) * scale;
canvas.width = width;
canvas.height = width;
var ctx = canvas.getContext("2d");
for (var y = -border; y < size + border; y++) {
for (var x = -border; x < size + border; x++) {
ctx.fillStyle = this.getModule(x, y) ? "#000000" : "#FFFFFF";
ctx.fillRect((x + border) * scale, (y + border) * scale, scale, scale);
}
}
};
// Returns a string of SVG code for an image depicting this QR Code, with the given number
// of border modules. The string always uses Unix newlines (\n), regardless of the platform.
this.toSvgString = function(border) {
if (border < 0)
throw "Border must be non-negative";
var parts = [];
for (var y = 0; y < size; y++) {
for (var x = 0; x < size; x++) {
if (this.getModule(x, y))
parts.push("M" + (x + border) + "," + (y + border) + "h1v1h-1z");
}
}
return '<?xml version="1.0" encoding="UTF-8"?>\n' +
'<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n' +
'<svg xmlns="http://www.w3.org/2000/svg" version="1.1" viewBox="0 0 ' +
(size + border * 2) + ' ' + (size + border * 2) + '" stroke="none">\n' +
'\t<rect width="100%" height="100%" fill="#FFFFFF"/>\n' +
'\t<path d="' + parts.join(" ") + '" fill="#000000"/>\n' +
'</svg>\n';
};
/*---- Private helper methods for constructor: Drawing function modules ----*/
// Reads this object's version field, and draws and marks all function modules.
function drawFunctionPatterns() {
// Draw horizontal and vertical timing patterns
for (var i = 0; i < size; i++) {
setFunctionModule(6, i, i % 2 == 0);
setFunctionModule(i, 6, i % 2 == 0);
}
// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
drawFinderPattern(3, 3);
drawFinderPattern(size - 4, 3);
drawFinderPattern(3, size - 4);
// Draw numerous alignment patterns
var alignPatPos = getAlignmentPatternPositions();
var numAlign = alignPatPos.length;
for (var i = 0; i < numAlign; i++) {
for (var j = 0; j < numAlign; j++) {
// Don't draw on the three finder corners
if (!(i == 0 && j == 0 || i == 0 && j == numAlign - 1 || i == numAlign - 1 && j == 0))
drawAlignmentPattern(alignPatPos[i], alignPatPos[j]);
}
}
// Draw configuration data
drawFormatBits(0); // Dummy mask value; overwritten later in the constructor
drawVersion();
}
// Draws two copies of the format bits (with its own error correction code)
// based on the given mask and this object's error correction level field.
function drawFormatBits(mask) {
// Calculate error correction code and pack bits
var data = errCorLvl.formatBits << 3 | mask; // errCorrLvl is uint2, mask is uint3
var rem = data;
for (var i = 0; i < 10; i++)
rem = (rem << 1) ^ ((rem >>> 9) * 0x537);
var bits = (data << 10 | rem) ^ 0x5412; // uint15
if (bits >>> 15 != 0)
throw "Assertion error";
// Draw first copy
for (var i = 0; i <= 5; i++)
setFunctionModule(8, i, getBit(bits, i));
setFunctionModule(8, 7, getBit(bits, 6));
setFunctionModule(8, 8, getBit(bits, 7));
setFunctionModule(7, 8, getBit(bits, 8));
for (var i = 9; i < 15; i++)
setFunctionModule(14 - i, 8, getBit(bits, i));
// Draw second copy
for (var i = 0; i < 8; i++)
setFunctionModule(size - 1 - i, 8, getBit(bits, i));
for (var i = 8; i < 15; i++)
setFunctionModule(8, size - 15 + i, getBit(bits, i));
setFunctionModule(8, size - 8, true); // Always black
}
// Draws two copies of the version bits (with its own error correction code),
// based on this object's version field, iff 7 <= version <= 40.
function drawVersion() {
if (version < 7)
return;
// Calculate error correction code and pack bits
var rem = version; // version is uint6, in the range [7, 40]
for (var i = 0; i < 12; i++)
rem = (rem << 1) ^ ((rem >>> 11) * 0x1F25);
var bits = version << 12 | rem; // uint18
if (bits >>> 18 != 0)
throw "Assertion error";
// Draw two copies
for (var i = 0; i < 18; i++) {
var bit = getBit(bits, i);
var a = size - 11 + i % 3;
var b = Math.floor(i / 3);
setFunctionModule(a, b, bit);
setFunctionModule(b, a, bit);
}
}
// Draws a 9*9 finder pattern including the border separator,
// with the center module at (x, y). Modules can be out of bounds.
function drawFinderPattern(x, y) {
for (var dy = -4; dy <= 4; dy++) {
for (var dx = -4; dx <= 4; dx++) {
var dist = Math.max(Math.abs(dx), Math.abs(dy)); // Chebyshev/infinity norm
var xx = x + dx, yy = y + dy;
if (0 <= xx && xx < size && 0 <= yy && yy < size)
setFunctionModule(xx, yy, dist != 2 && dist != 4);
}
}
}
// Draws a 5*5 alignment pattern, with the center module
// at (x, y). All modules must be in bounds.
function drawAlignmentPattern(x, y) {
for (var dy = -2; dy <= 2; dy++) {
for (var dx = -2; dx <= 2; dx++)
setFunctionModule(x + dx, y + dy, Math.max(Math.abs(dx), Math.abs(dy)) != 1);
}
}
// Sets the color of a module and marks it as a function module.
// Only used by the constructor. Coordinates must be in bounds.
function setFunctionModule(x, y, isBlack) {
modules[y][x] = isBlack;
isFunction[y][x] = true;
}
/*---- Private helper methods for constructor: Codewords and masking ----*/
// Returns a new byte string representing the given data with the appropriate error correction
// codewords appended to it, based on this object's version and error correction level.
function addEccAndInterleave(data) {
if (data.length != QrCode.getNumDataCodewords(version, errCorLvl))
throw "Invalid argument";
// Calculate parameter numbers
var numBlocks = QrCode.NUM_ERROR_CORRECTION_BLOCKS[errCorLvl.ordinal][version];
var blockEccLen = QrCode.ECC_CODEWORDS_PER_BLOCK [errCorLvl.ordinal][version];
var rawCodewords = Math.floor(QrCode.getNumRawDataModules(version) / 8);
var numShortBlocks = numBlocks - rawCodewords % numBlocks;
var shortBlockLen = Math.floor(rawCodewords / numBlocks);
// Split data into blocks and append ECC to each block
var blocks = [];
var rs = new ReedSolomonGenerator(blockEccLen);
for (var i = 0, k = 0; i < numBlocks; i++) {
var dat = data.slice(k, k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1));
k += dat.length;
var ecc = rs.getRemainder(dat);
if (i < numShortBlocks)
dat.push(0);
blocks.push(dat.concat(ecc));
}
// Interleave (not concatenate) the bytes from every block into a single sequence
var result = [];
for (var i = 0; i < blocks[0].length; i++) {
for (var j = 0; j < blocks.length; j++) {
// Skip the padding byte in short blocks
if (i != shortBlockLen - blockEccLen || j >= numShortBlocks)
result.push(blocks[j][i]);
}
}
if (result.length != rawCodewords)
throw "Assertion error";
return result;
}
// Draws the given sequence of 8-bit codewords (data and error correction) onto the entire
// data area of this QR Code. Function modules need to be marked off before this is called.
function drawCodewords(data) {
if (data.length != Math.floor(QrCode.getNumRawDataModules(version) / 8))
throw "Invalid argument";
var i = 0; // Bit index into the data
// Do the funny zigzag scan
for (var right = size - 1; right >= 1; right -= 2) { // Index of right column in each column pair
if (right == 6)
right = 5;
for (var vert = 0; vert < size; vert++) { // Vertical counter
for (var j = 0; j < 2; j++) {
var x = right - j; // Actual x coordinate
var upward = ((right + 1) & 2) == 0;
var y = upward ? size - 1 - vert : vert; // Actual y coordinate
if (!isFunction[y][x] && i < data.length * 8) {
modules[y][x] = getBit(data[i >>> 3], 7 - (i & 7));
i++;
}
// If this QR Code has any remainder bits (0 to 7), they were assigned as
// 0/false/white by the constructor and are left unchanged by this method
}
}
}
if (i != data.length * 8)
throw "Assertion error";
}
// XORs the codeword modules in this QR Code with the given mask pattern.
// The function modules must be marked and the codeword bits must be drawn
// before masking. Due to the arithmetic of XOR, calling applyMask() with
// the same mask value a second time will undo the mask. A final well-formed
// QR Code needs exactly one (not zero, two, etc.) mask applied.
function applyMask(mask) {
if (mask < 0 || mask > 7)
throw "Mask value out of range";
for (var y = 0; y < size; y++) {
for (var x = 0; x < size; x++) {
var invert;
switch (mask) {
case 0: invert = (x + y) % 2 == 0; break;
case 1: invert = y % 2 == 0; break;
case 2: invert = x % 3 == 0; break;
case 3: invert = (x + y) % 3 == 0; break;
case 4: invert = (Math.floor(x / 3) + Math.floor(y / 2)) % 2 == 0; break;
case 5: invert = x * y % 2 + x * y % 3 == 0; break;
case 6: invert = (x * y % 2 + x * y % 3) % 2 == 0; break;
case 7: invert = ((x + y) % 2 + x * y % 3) % 2 == 0; break;
default: throw "Assertion error";
}
if (!isFunction[y][x] && invert)
modules[y][x] = !modules[y][x];
}
}
}
// Calculates and returns the penalty score based on state of this QR Code's current modules.
// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
function getPenaltyScore() {
var result = 0;
// Adjacent modules in row having same color, and finder-like patterns
for (var y = 0; y < size; y++) {
var runHistory = [0,0,0,0,0,0,0];
var color = false;
var runX = 0;
for (var x = 0; x < size; x++) {
if (modules[y][x] == color) {
runX++;
if (runX == 5)
result += QrCode.PENALTY_N1;
else if (runX > 5)
result++;
} else {
QrCode.addRunToHistory(runX, runHistory);
if (!color && QrCode.hasFinderLikePattern(runHistory))
result += QrCode.PENALTY_N3;
color = modules[y][x];
runX = 1;
}
}
QrCode.addRunToHistory(runX, runHistory);
if (color)
QrCode.addRunToHistory(0, runHistory); // Dummy run of white
if (QrCode.hasFinderLikePattern(runHistory))
result += QrCode.PENALTY_N3;
}
// Adjacent modules in column having same color, and finder-like patterns
for (var x = 0; x < size; x++) {
var runHistory = [0,0,0,0,0,0,0];
var color = false;
var runY = 0;
for (var y = 0; y < size; y++) {
if (modules[y][x] == color) {
runY++;
if (runY == 5)
result += QrCode.PENALTY_N1;
else if (runY > 5)
result++;
} else {
QrCode.addRunToHistory(runY, runHistory);
if (!color && QrCode.hasFinderLikePattern(runHistory))
result += QrCode.PENALTY_N3;
color = modules[y][x];
runY = 1;
}
}
QrCode.addRunToHistory(runY, runHistory);
if (color)
QrCode.addRunToHistory(0, runHistory); // Dummy run of white
if (QrCode.hasFinderLikePattern(runHistory))
result += QrCode.PENALTY_N3;
}
// 2*2 blocks of modules having same color
for (var y = 0; y < size - 1; y++) {
for (var x = 0; x < size - 1; x++) {
var color = modules[y][x];
if ( color == modules[y][x + 1] &&
color == modules[y + 1][x] &&
color == modules[y + 1][x + 1])
result += QrCode.PENALTY_N2;
}
}
// Balance of black and white modules
var black = 0;
modules.forEach(function(row) {
row.forEach(function(color) {
if (color)
black++;
});
});
var total = size * size; // Note that size is odd, so black/total != 1/2
// Compute the smallest integer k >= 0 such that (45-5k)% <= black/total <= (55+5k)%
var k = Math.ceil(Math.abs(black * 20 - total * 10) / total) - 1;
result += k * QrCode.PENALTY_N4;
return result;
}
// Returns an ascending list of positions of alignment patterns for this version number.
// Each position is in the range [0,177), and are used on both the x and y axes.
// This could be implemented as lookup table of 40 variable-length lists of integers.
function getAlignmentPatternPositions() {
if (version == 1)
return [];
else {
var numAlign = Math.floor(version / 7) + 2;
var step = (version == 32) ? 26 :
Math.ceil((size - 13) / (numAlign*2 - 2)) * 2;
var result = [6];
for (var pos = size - 7; result.length < numAlign; pos -= step)
result.splice(1, 0, pos);
return result;
}
}
// Returns true iff the i'th bit of x is set to 1.
function getBit(x, i) {
return ((x >>> i) & 1) != 0;
}
};
/*---- Static factory functions (high level) for QrCode ----*/
/*
* Returns a QR Code representing the given Unicode text string at the given error correction level.
* As a conservative upper bound, this function is guaranteed to succeed for strings that have 738 or fewer
* Unicode code points (not UTF-16 code units) if the low error correction level is used. The smallest possible
* QR Code version is automatically chosen for the output. The ECC level of the result may be higher than the
* ecl argument if it can be done without increasing the version.
*/
this.QrCode.encodeText = function(text, ecl) {
var segs = qrcodegen.QrSegment.makeSegments(text);
return this.encodeSegments(segs, ecl);
};
/*
* Returns a QR Code representing the given binary data at the given error correction level.
* This function always encodes using the binary segment mode, not any text mode. The maximum number of
* bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output.
* The ECC level of the result may be higher than the ecl argument if it can be done without increasing the version.
*/
this.QrCode.encodeBinary = function(data, ecl) {
var seg = qrcodegen.QrSegment.makeBytes(data);
return this.encodeSegments([seg], ecl);
};
/*---- Static factory functions (mid level) for QrCode ----*/
/*
* Returns a QR Code representing the given segments with the given encoding parameters.
* The smallest possible QR Code version within the given range is automatically
* chosen for the output. Iff boostEcl is true, then the ECC level of the result
* may be higher than the ecl argument if it can be done without increasing the
* version. The mask number is either between 0 to 7 (inclusive) to force that
* mask, or -1 to automatically choose an appropriate mask (which may be slow).
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and byte) to encode text in less space.
* This is a mid-level API; the high-level API is encodeText() and encodeBinary().
*/
this.QrCode.encodeSegments = function(segs, ecl, minVersion, maxVersion, mask, boostEcl) {
if (minVersion == undefined) minVersion = MIN_VERSION;
if (maxVersion == undefined) maxVersion = MAX_VERSION;
if (mask == undefined) mask = -1;
if (boostEcl == undefined) boostEcl = true;
if (!(MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= MAX_VERSION) || mask < -1 || mask > 7)
throw "Invalid value";
// Find the minimal version number to use
var version, dataUsedBits;
for (version = minVersion; ; version++) {
var dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = qrcodegen.QrSegment.getTotalBits(segs, version);
if (dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
if (version >= maxVersion) // All versions in the range could not fit the given data
throw "Data too long";
}
// Increase the error correction level while the data still fits in the current version number
[this.Ecc.MEDIUM, this.Ecc.QUARTILE, this.Ecc.HIGH].forEach(function(newEcl) { // From low to high
if (boostEcl && dataUsedBits <= QrCode.getNumDataCodewords(version, newEcl) * 8)
ecl = newEcl;
});
// Concatenate all segments to create the data bit string
var bb = new BitBuffer();
segs.forEach(function(seg) {
bb.appendBits(seg.mode.modeBits, 4);
bb.appendBits(seg.numChars, seg.mode.numCharCountBits(version));
seg.getData().forEach(function(bit) {
bb.push(bit);
});
});
if (bb.length != dataUsedBits)
throw "Assertion error";
// Add terminator and pad up to a byte if applicable
var dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8;
if (bb.length > dataCapacityBits)
throw "Assertion error";
bb.appendBits(0, Math.min(4, dataCapacityBits - bb.length));
bb.appendBits(0, (8 - bb.length % 8) % 8);
if (bb.length % 8 != 0)
throw "Assertion error";
// Pad with alternating bytes until data capacity is reached
for (var padByte = 0xEC; bb.length < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bb.appendBits(padByte, 8);
// Pack bits into bytes in big endian
var dataCodewords = [];
while (dataCodewords.length * 8 < bb.length)
dataCodewords.push(0);
bb.forEach(function(bit, i) {
dataCodewords[i >>> 3] |= bit << (7 - (i & 7));
});
// Create the QR Code object
return new this(version, ecl, dataCodewords, mask);
};
/*---- Private static helper functions for QrCode ----*/
var QrCode = {}; // Private object to assign properties to. Not the same object as 'this.QrCode'.
// Returns the number of data bits that can be stored in a QR Code of the given version number, after
// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
QrCode.getNumRawDataModules = function(ver) {
if (ver < MIN_VERSION || ver > MAX_VERSION)
throw "Version number out of range";
var result = (16 * ver + 128) * ver + 64;
if (ver >= 2) {
var numAlign = Math.floor(ver / 7) + 2;
result -= (25 * numAlign - 10) * numAlign - 55;
if (ver >= 7)
result -= 36;
}
return result;
};
// Returns the number of 8-bit data (i.e. not error correction) codewords contained in any
// QR Code of the given version number and error correction level, with remainder bits discarded.
// This stateless pure function could be implemented as a (40*4)-cell lookup table.
QrCode.getNumDataCodewords = function(ver, ecl) {
return Math.floor(QrCode.getNumRawDataModules(ver) / 8) -
QrCode.ECC_CODEWORDS_PER_BLOCK [ecl.ordinal][ver] *
QrCode.NUM_ERROR_CORRECTION_BLOCKS[ecl.ordinal][ver];
};
// Inserts the given value to the front of the given array, which shifts over the
// existing values and deletes the last value. A helper function for getPenaltyScore().
QrCode.addRunToHistory = function(run, history) {
history.pop();
history.unshift(run);
};
// Tests whether the given run history has the pattern of ratio 1:1:3:1:1 in the middle, and
// surrounded by at least 4 on either or both ends. A helper function for getPenaltyScore().
// Must only be called immediately after a run of white modules has ended.
QrCode.hasFinderLikePattern = function(runHistory) {
var n = runHistory[1];
return n > 0 && runHistory[2] == n && runHistory[4] == n && runHistory[5] == n
&& runHistory[3] == n * 3 && Math.max(runHistory[0], runHistory[6]) >= n * 4;
};
/*---- Constants and tables for QrCode ----*/
var MIN_VERSION = 1; // The minimum version number supported in the QR Code Model 2 standard
var MAX_VERSION = 40; // The maximum version number supported in the QR Code Model 2 standard
Object.defineProperty(this.QrCode, "MIN_VERSION", {value:MIN_VERSION});
Object.defineProperty(this.QrCode, "MAX_VERSION", {value:MAX_VERSION});
// For use in getPenaltyScore(), when evaluating which mask is best.
QrCode.PENALTY_N1 = 3;
QrCode.PENALTY_N2 = 3;
QrCode.PENALTY_N3 = 40;
QrCode.PENALTY_N4 = 10;
QrCode.ECC_CODEWORDS_PER_BLOCK = [
// Version: (note that index 0 is for padding, and is set to an illegal value)
// 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level
[null, 7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30], // Low
[null, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28], // Medium
[null, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30], // Quartile
[null, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30], // High
];
QrCode.NUM_ERROR_CORRECTION_BLOCKS = [
// Version: (note that index 0 is for padding, and is set to an illegal value)
// 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 Error correction level
[null, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 6, 7, 8, 8, 9, 9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25], // Low
[null, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 5, 8, 9, 9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49], // Medium
[null, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8, 8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68], // Quartile
[null, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81], // High
];
/*---- Public helper enumeration ----*/
/*
* The error correction level in a QR Code symbol. Immutable.
*/
this.QrCode.Ecc = {
LOW : new Ecc(0, 1), // The QR Code can tolerate about 7% erroneous codewords
MEDIUM : new Ecc(1, 0), // The QR Code can tolerate about 15% erroneous codewords
QUARTILE: new Ecc(2, 3), // The QR Code can tolerate about 25% erroneous codewords
HIGH : new Ecc(3, 2), // The QR Code can tolerate about 30% erroneous codewords
};
// Private constructor.
function Ecc(ord, fb) {
// (Public) In the range 0 to 3 (unsigned 2-bit integer)
Object.defineProperty(this, "ordinal", {value:ord});
// (Package-private) In the range 0 to 3 (unsigned 2-bit integer)
Object.defineProperty(this, "formatBits", {value:fb});
}
/*---- Data segment class ----*/
/*
* A segment of character/binary/control data in a QR Code symbol.
* Instances of this class are immutable.
* The mid-level way to create a segment is to take the payload data
* and call a static factory function such as QrSegment.makeNumeric().
* The low-level way to create a segment is to custom-make the bit buffer
* and call the QrSegment() constructor with appropriate values.
* This segment class imposes no length restrictions, but QR Codes have restrictions.
* Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
* Any segment longer than this is meaningless for the purpose of generating QR Codes.
* This constructor creates a QR Code segment with the given attributes and data.
* The character count (numChars) must agree with the mode and the bit buffer length,
* but the constraint isn't checked. The given bit buffer is cloned and stored.
*/
this.QrSegment = function(mode, numChars, bitData) {
/*---- Constructor (low level) ----*/
if (numChars < 0 || !(mode instanceof Mode))
throw "Invalid argument";
// The data bits of this segment. Accessed through getData().
bitData = bitData.slice(); // Make defensive copy
// The mode indicator of this segment.
Object.defineProperty(this, "mode", {value:mode});
// The length of this segment's unencoded data. Measured in characters for
// numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
// Always zero or positive. Not the same as the data's bit length.
Object.defineProperty(this, "numChars", {value:numChars});
// Returns a new copy of the data bits of this segment.
this.getData = function() {
return bitData.slice(); // Make defensive copy
};
};
/*---- Static factory functions (mid level) for QrSegment ----*/
/*
* Returns a segment representing the given binary data encoded in
* byte mode. All input byte arrays are acceptable. Any text string
* can be converted to UTF-8 bytes and encoded as a byte mode segment.
*/
this.QrSegment.makeBytes = function(data) {
var bb = new BitBuffer();
data.forEach(function(b) {
bb.appendBits(b, 8);
});
return new this(this.Mode.BYTE, data.length, bb);
};
/*
* Returns a segment representing the given string of decimal digits encoded in numeric mode.
*/
this.QrSegment.makeNumeric = function(digits) {
if (!this.NUMERIC_REGEX.test(digits))
throw "String contains non-numeric characters";
var bb = new BitBuffer();
for (var i = 0; i < digits.length; ) { // Consume up to 3 digits per iteration
var n = Math.min(digits.length - i, 3);
bb.appendBits(parseInt(digits.substring(i, i + n), 10), n * 3 + 1);
i += n;
}
return new this(this.Mode.NUMERIC, digits.length, bb);
};
/*
* Returns a segment representing the given text string encoded in alphanumeric mode.
* The characters allowed are: 0 to 9, A to Z (uppercase only), space,
* dollar, percent, asterisk, plus, hyphen, period, slash, colon.
*/
this.QrSegment.makeAlphanumeric = function(text) {
if (!this.ALPHANUMERIC_REGEX.test(text))
throw "String contains unencodable characters in alphanumeric mode";
var bb = new BitBuffer();
var i;
for (i = 0; i + 2 <= text.length; i += 2) { // Process groups of 2
var temp = QrSegment.ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)) * 45;
temp += QrSegment.ALPHANUMERIC_CHARSET.indexOf(text.charAt(i + 1));
bb.appendBits(temp, 11);
}
if (i < text.length) // 1 character remaining
bb.appendBits(QrSegment.ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)), 6);
return new this(this.Mode.ALPHANUMERIC, text.length, bb);
};
/*
* Returns a new mutable list of zero or more segments to represent the given Unicode text string.
* The result may use various segment modes and switch modes to optimize the length of the bit stream.
*/
this.QrSegment.makeSegments = function(text) {
// Select the most efficient segment encoding automatically
if (text == "")
return [];
else if (this.NUMERIC_REGEX.test(text))
return [this.makeNumeric(text)];
else if (this.ALPHANUMERIC_REGEX.test(text))
return [this.makeAlphanumeric(text)];
else
return [this.makeBytes(toUtf8ByteArray(text))];
};
/*
* Returns a segment representing an Extended Channel Interpretation
* (ECI) designator with the given assignment value.
*/
this.QrSegment.makeEci = function(assignVal) {
var bb = new BitBuffer();
if (assignVal < 0)
throw "ECI assignment value out of range";
else if (assignVal < (1 << 7))
bb.appendBits(assignVal, 8);
else if (assignVal < (1 << 14)) {
bb.appendBits(2, 2);
bb.appendBits(assignVal, 14);
} else if (assignVal < 1000000) {
bb.appendBits(6, 3);
bb.appendBits(assignVal, 21);
} else
throw "ECI assignment value out of range";
return new this(this.Mode.ECI, 0, bb);
};
// (Package-private) Calculates and returns the number of bits needed to encode the given segments at the
// given version. The result is infinity if a segment has too many characters to fit its length field.
this.QrSegment.getTotalBits = function(segs, version) {
var result = 0;
for (var i = 0; i < segs.length; i++) {
var seg = segs[i];
var ccbits = seg.mode.numCharCountBits(version);
if (seg.numChars >= (1 << ccbits))
return Infinity; // The segment's length doesn't fit the field's bit width
result += 4 + ccbits + seg.getData().length;
}
return result;
};
/*---- Constants for QrSegment ----*/
var QrSegment = {}; // Private object to assign properties to. Not the same object as 'this.QrSegment'.
// (Public) Describes precisely all strings that are encodable in numeric mode.
// To test whether a string s is encodable: var ok = NUMERIC_REGEX.test(s);
// A string is encodable iff each character is in the range 0 to 9.
this.QrSegment.NUMERIC_REGEX = /^[0-9]*$/;
// (Public) Describes precisely all strings that are encodable in alphanumeric mode.
// To test whether a string s is encodable: var ok = ALPHANUMERIC_REGEX.test(s);
// A string is encodable iff each character is in the following set: 0 to 9, A to Z
// (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
this.QrSegment.ALPHANUMERIC_REGEX = /^[A-Z0-9 $%*+.\/:-]*$/;
// (Private) The set of all legal characters in alphanumeric mode,
// where each character value maps to the index in the string.
QrSegment.ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
/*---- Public helper enumeration ----*/
/*
* Describes how a segment's data bits are interpreted. Immutable.
*/
this.QrSegment.Mode = { // Constants
NUMERIC : new Mode(0x1, [10, 12, 14]),
ALPHANUMERIC: new Mode(0x2, [ 9, 11, 13]),
BYTE : new Mode(0x4, [ 8, 16, 16]),
KANJI : new Mode(0x8, [ 8, 10, 12]),
ECI : new Mode(0x7, [ 0, 0, 0]),
};
// Private constructor.
function Mode(mode, ccbits) {
// (Package-private) The mode indicator bits, which is a uint4 value (range 0 to 15).
Object.defineProperty(this, "modeBits", {value:mode});
// (Package-private) Returns the bit width of the character count field for a segment in
// this mode in a QR Code at the given version number. The result is in the range [0, 16].
this.numCharCountBits = function(ver) {
return ccbits[Math.floor((ver + 7) / 17)];
};
}
/*---- Private helper functions and classes ----*/
// Returns a new array of bytes representing the given string encoded in UTF-8.
function toUtf8ByteArray(str) {
str = encodeURI(str);
var result = [];
for (var i = 0; i < str.length; i++) {
if (str.charAt(i) != "%")
result.push(str.charCodeAt(i));
else {
result.push(parseInt(str.substring(i + 1, i + 3), 16));
i += 2;
}
}
return result;
}
/*
* A private helper class that computes the Reed-Solomon error correction codewords for a sequence of
* data codewords at a given degree. Objects are immutable, and the state only depends on the degree.
* This class exists because each data block in a QR Code shares the same the divisor polynomial.
* This constructor creates a Reed-Solomon ECC generator for the given degree. This could be implemented
* as a lookup table over all possible parameter values, instead of as an algorithm.
*/
function ReedSolomonGenerator(degree) {
if (degree < 1 || degree > 255)
throw "Degree out of range";
// Coefficients of the divisor polynomial, stored from highest to lowest power, excluding the leading term which
// is always 1. For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
var coefficients = [];
// Start with the monomial x^0
for (var i = 0; i < degree - 1; i++)
coefficients.push(0);
coefficients.push(1);
// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
// drop the highest term, and store the rest of the coefficients in order of descending powers.
// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
var root = 1;
for (var i = 0; i < degree; i++) {
// Multiply the current product by (x - r^i)
for (var j = 0; j < coefficients.length; j++) {
coefficients[j] = ReedSolomonGenerator.multiply(coefficients[j], root);
if (j + 1 < coefficients.length)
coefficients[j] ^= coefficients[j + 1];
}
root = ReedSolomonGenerator.multiply(root, 0x02);
}
// Computes and returns the Reed-Solomon error correction codewords for the given
// sequence of data codewords. The returned object is always a new byte array.
// This method does not alter this object's state (because it is immutable).
this.getRemainder = function(data) {
// Compute the remainder by performing polynomial division
var result = coefficients.map(function() { return 0; });
data.forEach(function(b) {
var factor = b ^ result.shift();
result.push(0);
coefficients.forEach(function(coef, i) {
result[i] ^= ReedSolomonGenerator.multiply(coef, factor);
});
});
return result;
};
}
// This static function returns the product of the two given field elements modulo GF(2^8/0x11D). The arguments and
// result are unsigned 8-bit integers. This could be implemented as a lookup table of 256*256 entries of uint8.
ReedSolomonGenerator.multiply = function(x, y) {
if (x >>> 8 != 0 || y >>> 8 != 0)
throw "Byte out of range";
// Russian peasant multiplication
var z = 0;
for (var i = 7; i >= 0; i--) {
z = (z << 1) ^ ((z >>> 7) * 0x11D);
z ^= ((y >>> i) & 1) * x;
}
if (z >>> 8 != 0)
throw "Assertion error";
return z;
};
/*
* A private helper class that represents an appendable sequence of bits (0s and 1s).
* Mainly used by QrSegment. This constructor creates an empty bit buffer (length 0).
*/
function BitBuffer() {
Array.call(this);
// Appends the given number of low-order bits of the given value
// to this buffer. Requires 0 <= len <= 31 and 0 <= val < 2^len.
this.appendBits = function(val, len) {
if (len < 0 || len > 31 || val >>> len != 0)
throw "Value out of range";
for (var i = len - 1; i >= 0; i--) // Append bit by bit
this.push((val >>> i) & 1);
};
}
BitBuffer.prototype = Object.create(Array.prototype);
BitBuffer.prototype.constructor = BitBuffer;
};
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