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QR-Code-generator/qrcodegen.js

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/*
* QR Code generator library (JavaScript)
*
* Copyright (c) 2016 Project Nayuki
* https://www.nayuki.io/page/qr-code-generator-library
*
* (MIT License)
* 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 inside this namespace:
* - Function encodeText(str text, QrCode.Ecc ecl) -> QrCode
* - Function encodeTextToSegment(str text) -> QrSegment
* - Function encodeBinary(list<int> data, QrCode.Ecc ecl) -> QrCode
* - Function encodeSegments(list<QrSegment> segs, QrCode.Ecc ecl) -> QrCode
* - Class QrCode:
* - Constructor QrCode(QrCode qr, int mask)
* - Constructor QrCode(list<int> bytes, int mask, int version, QrCode.Ecc ecl)
* - Method getVersion() -> int
* - Method getSize() -> int
* - Method getErrorCorrectionLevel() -> QrCode.Ecc
* - Method getMask() -> int
* - Method getModule(int x, int y) -> int
* - Method isFunctionModule(int x, int y) -> bool
* - Method toSvgString(int border) -> str
* - Enum Ecc:
* - Constants LOW, MEDIUM, QUARTILE, HIGH
* - Fields int ordinal, formatBits
* - Class QrSegment:
* - Function makeBytes(list<int> data) -> QrSegment
* - Function makeNumeric(str data) -> QrSegment
* - Function makeAlphanumeric(str data) -> QrSegment
* - Constructor QrSegment(QrSegment.Mode mode, int numChars, list<int> bitData)
* - Method getMode() -> QrSegment.Mode
* - Method getNumChars() -> int
* - Method getBits() -> list<int>
* - Enum Mode:
* - Constants NUMERIC, ALPHANUMERIC, BYTE, KANJI
* - Method getModeBits() -> int
* - Method numCharCountBits(int ver) -> int
*/
var qrcodegen = new function() {
/*---- Public static factory functions for QrCode ----*/
/*
* Returns a QR Code symbol 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). The smallest possible QR Code version is automatically chosen for the output.
*/
this.encodeText = function(text, ecl) {
var seg = this.encodeTextToSegment(text);
return this.encodeSegments([seg], ecl);
};
/*
* Returns a single QR segment representing the given Unicode text string.
*/
this.encodeTextToSegment = function(text) {
// Select the most efficient segment encoding automatically
if (QrSegment.NUMERIC_REGEX.test(text))
return this.QrSegment.makeNumeric(text);
else if (QrSegment.ALPHANUMERIC_REGEX.test(text))
return this.QrSegment.makeAlphanumeric(text);
else
return this.QrSegment.makeBytes(toUtf8ByteArray(text));
};
/*
* Returns a QR Code symbol representing the given binary data string 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.
*/
this.encodeBinary = function(data, ecl) {
var seg = this.QrSegment.makeBytes(data);
return this.encodeSegments([seg], ecl);
};
/*
* Returns a QR Code symbol representing the given data segments at the given error
* correction level. The smallest possible QR Code version is automatically chosen for the output.
* This function allows the user to create a custom sequence of segments that switches
* between modes (such as alphanumeric and binary) to encode text more efficiently. This
* function is considered to be lower level than simply encoding text or binary data.
*/
this.encodeSegments = function(segs, ecl) {
// Find the minimal version number to use
var version, dataCapacityBits;
outer:
for (version = 1; ; version++) { // Increment until the data fits in the QR Code
if (version > 40) // All versions could not fit the given data
throw "Data too long";
dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8; // Number of data bits available
// Calculate the total number of bits needed at this version number
// to encode all the segments (i.e. segment metadata and payloads)
var dataUsedBits = 0;
for (var i = 0; i < segs.length; i++) {
var seg = segs[i];
if (seg.numChars < 0)
throw "Assertion error";
var ccbits = seg.getMode().numCharCountBits(version);
if (seg.getNumChars() >= (1 << ccbits)) {
// Segment length value doesn't fit in the length field's bit-width, so fail immediately
continue outer;
}
dataUsedBits += 4 + ccbits + seg.getBits().length;
}
if (dataUsedBits <= dataCapacityBits)
break; // This version number is found to be suitable
}
// Create the data bit string by concatenating all segments
var bb = new BitBuffer();
segs.forEach(function(seg) {
bb.appendBits(seg.getMode().getModeBits(), 4);
bb.appendBits(seg.getNumChars(), seg.getMode().numCharCountBits(version));
bb.appendData(seg);
});
// Add terminator and pad up to a byte if applicable
bb.appendBits(0, Math.min(4, dataCapacityBits - bb.bitLength()));
bb.appendBits(0, (8 - bb.bitLength() % 8) % 8);
// Pad with alternate bytes until data capacity is reached
for (var padByte = 0xEC; bb.bitLength() < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
bb.appendBits(padByte, 8);
if (bb.bitLength() % 8 != 0)
throw "Assertion error";
// Create the QR Code symbol
return new this.QrCode(bb.getBytes(), -1, version, ecl);
};
/*---- QR Code symbol class ----*/
/*
* A class that represents an immutable square grid of black and white cells for a QR Code symbol,
* with associated static functions to create a QR Code from user-supplied textual or binary data.
* This class covers the QR Code model 2 specification, supporting all versions (sizes)
* from 1 to 40, all 4 error correction levels.
*
* This constructor can be called in one of two ways:
* - new QrCode(bytes, mask, version, errCorLvl):
* Creates a new QR Code symbol with the given version number, error correction level, binary data array,
* and mask number. This cumbersome constructor can be invoked directly by the user, but is considered
* to be even lower level than qrcodegen.encodeSegments().
* - new QrCode(qr, mask):
* Creates a new QR Code symbol based on the given existing object, but with a potentially different
* mask pattern. The version, error correction level, codewords, etc. of the newly created object are
* all identical to the argument object; only the mask may differ.
* In both cases, mask = -1 is for automatic choice or 0 to 7 for fixed choice.
*/
this.QrCode = function(initData, mask, version, errCorLvl) {
/*-- Constructor --*/
// Handle simple scalar fields
if (mask < -1 || mask > 7)
throw "Mask value out of range";
if (initData instanceof Array) {
if (version < 1 || version > 40)
throw "Version value out of range";
} else if (initData instanceof qrcodegen.QrCode) {
version = initData.getVersion();
errCorLvl = initData.getErrorCorrectionLevel();
} else
throw "Invalid initial data";
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 = [];
var isFunction = [];
for (var i = 0; i < size; i++) {
modules.push(row.slice());
isFunction.push(row.slice());
}
// Handle grid fields
if (initData instanceof Array) {
// Draw function patterns, draw all codewords
drawFunctionPatterns();
var allCodewords = appendErrorCorrection(initData);
drawCodewords(allCodewords);
} else if (initData instanceof qrcodegen.QrCode) {
for (var y = 0; y < size; y++) {
for (var x = 0; x < size; x++) {
modules[y][x] = initData.getModule(x, y) == 1;
isFunction[y][x] = initData.isFunctionModule(x, y);
}
}
applyMask(initData.getMask()); // Undo old mask
} else
throw "Invalid initial data";
// Handle 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
/*-- Accessor methods --*/
// Returns this QR Code symbol's version number, which is always between 1 and 40 (inclusive).
this.getVersion = function() {
return version;
};
// Returns the width and height of this QR Code symbol, measured in modules.
// Always equal to version * 4 + 17, in the range 21 to 177.
this.getSize = function() {
return size;
};
// Returns the error correction level used in this QR Code symbol.
this.getErrorCorrectionLevel = function() {
return errCorLvl;
};
// Returns the mask pattern used in this QR Code symbol, in the range 0 to 7 (i.e. unsigned 3-bit integer).
// Note that even if a constructor was called with automatic masking requested
// (mask = -1), the resulting object will still have a mask value between 0 and 7.
this.getMask = function() {
return mask;
};
// Returns the color of the module (pixel) at the given coordinates, which is either 0 for white or 1 for black. The top
// left corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then 0 (white) is returned.
this.getModule = function(x, y) {
if (0 <= x && x < size && 0 <= y && y < size)
return modules[y][x] ? 1 : 0;
else
return 0; // Infinite white border
};
// Tests whether the module at the given coordinates is a function module (true) or not (false). The top left
// corner has the coordinates (x=0, y=0). If the given coordinates are out of bounds, then false is returned.
this.isFunctionModule = function(x, y) {
if (0 <= x && x < size && 0 <= y && y < size)
return isFunction[y][x];
else
return false; // Infinite border
};
/*-- Public instance methods --*/
// Based on the given number of border modules to add as padding, this returns a
// string whose contents represents an SVG XML file that depicts this QR Code symbol.
this.toSvgString = function(border) {
if (border < 0)
throw "Border must be non-negative";
var result = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
result += "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n";
result += "<svg xmlns=\"http://www.w3.org/2000/svg\" version=\"1.1\" viewBox=\"0 0 " + (size + border * 2) + " " + (size + border * 2) + "\">\n";
result += "\t<path d=\"";
var head = true;
for (var y = -border; y < size + border; y++) {
for (var x = -border; x < size + border; x++) {
if (this.getModule(x, y) == 1) {
if (head)
head = false;
else
result += " ";
result += "M" + (x + border) + "," + (y + border) + "h1v1h-1z";
}
}
}
result += "\" fill=\"#000000\" stroke-width=\"0\"/>\n";
result += "</svg>\n";
return result;
};
/*-- Private helper methods for constructor: Drawing function modules --*/
function drawFunctionPatterns() {
// Draw the 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 the numerous alignment patterns
var alignPatPos = QrCode.getAlignmentPatternPositions(version);
var numAlign = alignPatPos.length;
for (var i = 0; i < numAlign; i++) {
for (var j = 0; j < numAlign; j++) {
if (i == 0 && j == 0 || i == 0 && j == numAlign - 1 || i == numAlign - 1 && j == 0)
continue; // Skip the three finder corners
else
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);
data = data << 10 | rem;
data ^= 0x5412; // uint15
if (data >>> 15 != 0)
throw "Assertion error";
// Draw first copy
for (var i = 0; i <= 5; i++)
setFunctionModule(8, i, ((data >>> i) & 1) != 0);
setFunctionModule(8, 7, ((data >>> 6) & 1) != 0);
setFunctionModule(8, 8, ((data >>> 7) & 1) != 0);
setFunctionModule(7, 8, ((data >>> 8) & 1) != 0);
for (var i = 9; i < 15; i++)
setFunctionModule(14 - i, 8, ((data >>> i) & 1) != 0);
// Draw second copy
for (var i = 0; i <= 7; i++)
setFunctionModule(size - 1 - i, 8, ((data >>> i) & 1) != 0);
for (var i = 8; i < 15; i++)
setFunctionModule(8, size - 15 + i, ((data >>> i) & 1) != 0);
setFunctionModule(8, size - 8, true);
}
// Draws two copies of the version bits (with its own error correction code),
// based on this object's version field (which only has an effect for 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 data = version << 12 | rem; // uint18
if (data >>> 18 != 0)
throw "Assertion error";
// Draw two copies
for (var i = 0; i < 18; i++) {
var bit = ((data >>> i) & 1) != 0;
var a = size - 11 + i % 3, 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).
function drawFinderPattern(x, y) {
for (var i = -4; i <= 4; i++) {
for (var j = -4; j <= 4; j++) {
var dist = Math.max(Math.abs(i), Math.abs(j)); // Chebyshev/infinity norm
var xx = x + j, yy = y + i;
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).
function drawAlignmentPattern(x, y) {
for (var i = -2; i <= 2; i++) {
for (var j = -2; j <= 2; j++)
setFunctionModule(x + j, y + i, Math.max(Math.abs(i), Math.abs(j)) != 1);
}
}
// Sets the color of a module and marks it as a function module.
// Only used by the constructor. Coordinates must be in range.
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 appendErrorCorrection(data) {
if (data.length != QrCode.getNumDataCodewords(version, errCorLvl))
throw "Invalid argument";
var numBlocks = QrCode.NUM_ERROR_CORRECTION_BLOCKS[errCorLvl.ordinal][version];
var numEcc = QrCode.NUM_ERROR_CORRECTION_CODEWORDS[errCorLvl.ordinal][version];
if (numEcc % numBlocks != 0)
throw "Assertion error";
var eccLen = Math.floor(numEcc / numBlocks);
var numShortBlocks = numBlocks - Math.floor(QrCode.getNumRawDataModules(version) / 8) % numBlocks;
var shortBlockLen = Math.floor(QrCode.getNumRawDataModules(version) / (numBlocks * 8));
var blocks = [];
var rs = new ReedSolomonGenerator(eccLen);
for (var i = 0, k = 0; i < numBlocks; i++) {
var dat = data.slice(k, k + shortBlockLen - eccLen + (i < numShortBlocks ? 0 : 1));
k += dat.length;
var ecc = rs.getRemainder(dat);
if (i < numShortBlocks)
dat.push(0);
ecc.forEach(function(b) {
dat.push(b);
});
blocks.push(dat);
}
var result = [];
for (var i = 0; i < blocks[0].length; i++) {
for (var j = 0; j < blocks.length; j++) {
if (i != shortBlockLen - eccLen || j >= numShortBlocks)
result.push(blocks[j][i]);
}
}
if (result.length != Math.floor(QrCode.getNumRawDataModules(version) / 8))
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 symbol. 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 upwards = ((right & 2) == 0) ^ (x < 6);
var y = upwards ? size - 1 - vert : vert; // Actual y coordinate
if (!isFunction[y][x] && i < data.length * 8) {
modules[y][x] = ((data[i >>> 3] >>> (7 - (i & 7))) & 1) != 0;
i++;
}
}
}
}
if (i != data.length * 8)
throw "Assertion error";
}
// XORs the data modules in this QR Code with the given mask pattern. Due to XOR's mathematical
// properties, calling applyMask(m) twice with the same value is equivalent to no change at all.
// This means it is possible to apply a mask, undo it, and try another mask. Note that a final
// well-formed QR Code symbol needs exactly one mask applied (not zero, not two, etc.).
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";
}
modules[y][x] ^= invert & !isFunction[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
for (var y = 0; y < size; y++) {
var colorX = modules[y][0];
for (var x = 1, runX = 1; x < size; x++) {
if (modules[y][x] != colorX) {
colorX = modules[y][x];
runX = 1;
} else {
runX++;
if (runX == 5)
result += QrCode.PENALTY_N1;
else if (runX > 5)
result++;
}
}
}
// Adjacent modules in column having same color
for (var x = 0; x < size; x++) {
var colorY = modules[0][x];
for (var y = 1, runY = 1; y < size; y++) {
if (modules[y][x] != colorY) {
colorY = modules[y][x];
runY = 1;
} else {
runY++;
if (runY == 5)
result += QrCode.PENALTY_N1;
else if (runY > 5)
result++;
}
}
}
// 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;
}
}
// Finder-like pattern in rows
for (var y = 0; y < size; y++) {
for (var x = 0, bits = 0; x < size; x++) {
bits = ((bits << 1) & 0x7FF) | (modules[y][x] ? 1 : 0);
if (x >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated
result += QrCode.PENALTY_N3;
}
}
// Finder-like pattern in columns
for (var x = 0; x < size; x++) {
for (var y = 0, bits = 0; y < size; y++) {
bits = ((bits << 1) & 0x7FF) | (modules[y][x] ? 1 : 0);
if (y >= 10 && (bits == 0x05D || bits == 0x5D0)) // Needs 11 bits accumulated
result += QrCode.PENALTY_N3;
}
}
// Balance of black and white modules
var black = 0;
modules.forEach(function(row) {
row.forEach(function(color) {
if (color)
black++;
});
});
var total = size * size;
// Find smallest k such that (45-5k)% <= dark/total <= (55+5k)%
for (var k = 0; black*20 < (9-k)*total || black*20 > (11+k)*total; k++)
result += QrCode.PENALTY_N4;
return result;
}
};
/*---- Private static helper functions ----*/
var QrCode = {}; // Private object to assign properties to
// Returns a sequence of positions of the alignment patterns in ascending order. These positions are
// used on both the x and y axes. Each value in the resulting sequence is in the range [0, 177).
// This stateless pure function could be implemented as table of 40 variable-length lists of integers.
QrCode.getAlignmentPatternPositions = function(ver) {
if (ver < 1 || ver > 40)
throw "Version number out of range";
else if (ver == 1)
return [];
else {
var size = ver * 4 + 17;
var numAlign = Math.floor(ver / 7) + 2;
var step;
if (ver != 32)
step = Math.ceil((size - 13) / (2 * numAlign - 2)) * 2;
else // C-C-C-Combo breaker!
step = 26;
var result = [];
for (var i = numAlign - 1, pos = size - 7; i >= 1; i--, pos -= step)
result.push(pos);
result.push(6);
result.reverse();
return result;
}
};
// Returns the number of raw data modules (bits) available at the given version number.
// These data modules are used for both user data codewords and error correction codewords.
// This stateless pure function could be implemented as a 40-entry lookup table.
QrCode.getNumRawDataModules = function(ver) {
if (ver < 1 || ver > 40)
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 -= 18 * 2; // Subtract version information
}
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) {
if (ver < 1 || ver > 40)
throw "Version number out of range";
return Math.floor(QrCode.getNumRawDataModules(ver) / 8) - QrCode.NUM_ERROR_CORRECTION_CODEWORDS[ecl.ordinal][ver];
};
/*---- Tables of constants ----*/
// 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.NUM_ERROR_CORRECTION_CODEWORDS = [
// 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, 36, 40, 48, 60, 72, 80, 96, 104, 120, 132, 144, 168, 180, 196, 224, 224, 252, 270, 300, 312, 336, 360, 390, 420, 450, 480, 510, 540, 570, 570, 600, 630, 660, 720, 750], // Low
[null, 10, 16, 26, 36, 48, 64, 72, 88, 110, 130, 150, 176, 198, 216, 240, 280, 308, 338, 364, 416, 442, 476, 504, 560, 588, 644, 700, 728, 784, 812, 868, 924, 980, 1036, 1064, 1120, 1204, 1260, 1316, 1372], // Medium
[null, 13, 22, 36, 52, 72, 96, 108, 132, 160, 192, 224, 260, 288, 320, 360, 408, 448, 504, 546, 600, 644, 690, 750, 810, 870, 952, 1020, 1050, 1140, 1200, 1290, 1350, 1440, 1530, 1590, 1680, 1770, 1860, 1950, 2040], // Quartile
[null, 17, 28, 44, 64, 88, 112, 130, 156, 192, 224, 264, 308, 352, 384, 432, 480, 532, 588, 650, 700, 750, 816, 900, 960, 1050, 1110, 1200, 1260, 1350, 1440, 1530, 1620, 1710, 1800, 1890, 1980, 2100, 2220, 2310, 2430], // 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
];
/*
* A public helper enumeration that represents the error correction level used in a QR Code symbol.
* The fields 'ordinal' and 'formatBits' are in the range 0 to 3 (unsigned 2-bit integer).
*/
this.QrCode.Ecc = {
// Constants declared in ascending order of error protection
LOW : {ordinal: 0, formatBits: 1},
MEDIUM : {ordinal: 1, formatBits: 0},
QUARTILE: {ordinal: 2, formatBits: 3},
HIGH : {ordinal: 3, formatBits: 2},
};
/*---- Data segment class ----*/
/*
* A public class that represents a character string to be encoded in a QR Code symbol.
* Each segment has a mode, and a sequence of characters that is already encoded as
* a sequence of bits. Instances of this class are immutable.
* 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.QrSegment = function(mode, numChars, bitData) {
if (numChars < 0 || !(mode instanceof Mode))
throw "Invalid argument";
/*-- Accessor methods --*/
this.getMode = function() {
return mode;
};
this.getNumChars = function() {
return numChars;
};
this.getBits = function() {
return bitData.slice();
};
};
/*-- Public static factory functions --*/
// Returns a segment representing the given binary data encoded in byte mode.
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.getBits());
};
// Returns a segment representing the given string of decimal digits encoded in numeric mode.
this.QrSegment.makeNumeric = function(digits) {
if (!QrSegment.NUMERIC_REGEX.test(digits))
throw "String contains non-numeric characters";
var bb = new BitBuffer();
var i;
for (i = 0; i + 3 <= digits.length; i += 3) // Process groups of 3
bb.appendBits(parseInt(digits.substr(i, 3), 10), 10);
var rem = digits.length - i;
if (rem > 0) // 1 or 2 digits remaining
bb.appendBits(parseInt(digits.substring(i), 10), rem * 3 + 1);
return new this(this.Mode.NUMERIC, digits.length, bb.getBits());
};
// 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 (!QrSegment.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_ENCODING_TABLE[text.charCodeAt(i) - 32] * 45;
temp += QrSegment.ALPHANUMERIC_ENCODING_TABLE[text.charCodeAt(i + 1) - 32];
bb.appendBits(temp, 11);
}
if (i < text.length) // 1 character remaining
bb.appendBits(QrSegment.ALPHANUMERIC_ENCODING_TABLE[text.charCodeAt(i) - 32], 6);
return new this(this.Mode.ALPHANUMERIC, text.length, bb.getBits());
};
/*-- Constants --*/
var QrSegment = {}; // Private object to assign properties to
// Can test whether a string is encodable in numeric mode (such as by using QrSegment.makeNumeric()).
QrSegment.NUMERIC_REGEX = /^[0-9]*$/;
// Can test whether a string is encodable in alphanumeric mode (such as by using QrSegment.makeAlphanumeric()).
QrSegment.ALPHANUMERIC_REGEX = /^[A-Z0-9 $%*+.\/:-]*$/;
QrSegment.ALPHANUMERIC_ENCODING_TABLE = [
// SP, !, ", #, $, %, &, ', (, ), *, +, ,, -, ., /, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, :, ;, <, =, >, ?, @, // ASCII codes 32 to 64
36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, -1, // Array indices 0 to 32
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, // Array indices 33 to 58
// A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, // ASCII codes 65 to 90
];
/*
* A public helper enumeration that represents the mode field of a segment.
* Objects are immutable. Provides methods to retrieve closely related values.
*/
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]),
};
// Private constructor for the enum.
function Mode(mode, ccbits) {
// Returns an unsigned 4-bit integer value (range 0 to 15) representing the mode indicator bits for this mode object.
this.getModeBits = function() {
return mode;
};
// Returns the bit width of the segment character count field for this mode object at the given version number.
this.numCharCountBits = function(ver) {
if ( 1 <= ver && ver <= 9) return ccbits[0];
else if (10 <= ver && ver <= 26) return ccbits[1];
else if (27 <= ver && ver <= 40) return ccbits[2];
else throw "Version number out of range";
};
}
/*---- 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.substr(i + 1, 2), 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 the divisor polynomial does not need to be recalculated for every input.
* 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 = (root << 1) ^ ((root >>> 7) * 0x11D); // Multiply by 0x02 mod GF(2^8/0x11D)
}
// 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[0];
result.shift();
result.push(0);
for (var j = 0; j < result.length; j++)
result[j] ^= ReedSolomonGenerator.multiply(coefficients[j], 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.
* This constructor creates an empty bit buffer (length 0).
*/
function BitBuffer() {
// Array of bits; each item is the integer 0 or 1
var bitData = [];
/*-- Methods --*/
// Returns the number of bits in the buffer, which is a non-negative value.
this.bitLength = function() {
return bitData.length;
};
// Returns a copy of all bits.
this.getBits = function() {
return bitData.slice();
};
// Returns a copy of all bytes, padding up to the nearest byte.
this.getBytes = function() {
var result = [];
var numBytes = Math.ceil(bitData.length / 8);
for (var i = 0; i < numBytes; i++)
result.push(0);
bitData.forEach(function(bit, i) {
result[i >>> 3] |= bit << (7 - (i & 7));
});
return result;
};
// Appends the given number of bits of the given value to this sequence.
// If 0 <= len <= 31, then this requires 0 <= val < 2^len.
this.appendBits = function(val, len) {
if (len < 0 || len > 32 || len < 32 && (val >>> len) != 0)
throw "Value out of range";
for (var i = len - 1; i >= 0; i--) // Append bit by bit
bitData.push((val >>> i) & 1);
};
// Appends the bit data of the given segment to this bit buffer.
this.appendData = function(seg) {
seg.getBits().forEach(function(b) { // Append bit by bit
bitData.push(b);
});
};
}
};
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