diff --git a/index.html b/index.html new file mode 100644 index 0000000..2bf527a --- /dev/null +++ b/index.html @@ -0,0 +1,39 @@ + + + + + + QR Code Generator + + + + +

QR Code Generator

+ + + + + diff --git a/index.js b/index.js new file mode 100644 index 0000000..1d1008d --- /dev/null +++ b/index.js @@ -0,0 +1,60 @@ +console.log('here'); + +import { QrCode, Ecc } from './qrcodegen.js'; + +const saveBlob = (function() { + const a = document.createElement('a'); + document.body.appendChild(a); + a.style.display = 'none'; + return function saveData(blob, fileName) { + const url = window.URL.createObjectURL(blob); + a.href = url; + a.download = fileName; + a.click(); + }; +}()); + +const textElem = document.querySelector('#text'); +const canvasElem = document.querySelector('canvas'); +const downloadElem = document.querySelector('#download'); +const ctx = canvasElem.getContext('2d'); + +textElem.addEventListener('input', () => { + updateQRCode(textElem.value); +}); + +downloadElem.addEventListener('click', () => { + canvasElem.toBlob(blob => saveBlob(blob, 'qr-code')); +}); + + +function updateQRCode(s) { + downloadElem.disabled = s ? '' : true; + if (!s) { + canvasElem.width = 1; + return; + } + const qr = QrCode.encodeText(s, Ecc.MEDIUM); + const scale = 4; + const padding = 3; + const size = qr.size + padding * 2; + ctx.canvas.width = size * scale; + ctx.canvas.height = size * scale; + ctx.scale(scale, scale); + for (let y = 0; y < size; y++) { + for (let x = 0; x < size; x++) { + ctx.fillStyle = qr.getModule(x - padding, y - padding) ? 'black' : 'white'; + ctx.fillRect(x, y, 1, 1); + } + } + //const img = new Image(); + //img.src = ctx.canvas.toDataURL(); + //qrCodesElem.appendChild(el('div', { + // className: 'qrcode', + //}, [ + // el('div', {textContent: s}), + // img, + //])); +} + +console.log('here'); \ No newline at end of file diff --git a/qrcodegen.js b/qrcodegen.js new file mode 100644 index 0000000..32dc493 --- /dev/null +++ b/qrcodegen.js @@ -0,0 +1,827 @@ +/* + * QR Code generator library (TypeScript) + * + * 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"; +/*---- QR Code symbol class ----*/ +/* + * 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 dark and light 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.) + */ +class QrCode { + /*-- Constructor (low level) and fields --*/ + // 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. + constructor( + // The version number of this QR Code, which is between 1 and 40 (inclusive). + // This determines the size of this barcode. + version, + // The error correction level used in this QR Code. + errorCorrectionLevel, dataCodewords, msk) { + this.version = version; + this.errorCorrectionLevel = errorCorrectionLevel; + // The modules of this QR Code (false = light, true = dark). + // Immutable after constructor finishes. Accessed through getModule(). + this.modules = []; + // Indicates function modules that are not subjected to masking. Discarded when constructor finishes. + this.isFunction = []; + // Check scalar arguments + if (version < QrCode.MIN_VERSION || version > QrCode.MAX_VERSION) + throw "Version value out of range"; + if (msk < -1 || msk > 7) + throw "Mask value out of range"; + this.size = version * 4 + 17; + // Initialize both grids to be size*size arrays of Boolean false + let row = []; + for (let i = 0; i < this.size; i++) + row.push(false); + for (let i = 0; i < this.size; i++) { + this.modules.push(row.slice()); // Initially all light + this.isFunction.push(row.slice()); + } + // Compute ECC, draw modules + this.drawFunctionPatterns(); + const allCodewords = this.addEccAndInterleave(dataCodewords); + this.drawCodewords(allCodewords); + // Do masking + if (msk == -1) { // Automatically choose best mask + let minPenalty = 1000000000; + for (let i = 0; i < 8; i++) { + this.applyMask(i); + this.drawFormatBits(i); + const penalty = this.getPenaltyScore(); + if (penalty < minPenalty) { + msk = i; + minPenalty = penalty; + } + this.applyMask(i); // Undoes the mask due to XOR + } + } + assert(0 <= msk && msk <= 7); + this.mask = msk; + this.applyMask(msk); // Apply the final choice of mask + this.drawFormatBits(msk); // Overwrite old format bits + this.isFunction = []; + } + /*-- Static factory functions (high level) --*/ + // 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. + static encodeText(text, ecl) { + const segs = QrSegment.makeSegments(text); + return QrCode.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. + static encodeBinary(data, ecl) { + const seg = QrSegment.makeBytes(data); + return QrCode.encodeSegments([seg], ecl); + } + /*-- Static factory functions (mid level) --*/ + // 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(). + static encodeSegments(segs, ecl, minVersion = 1, maxVersion = 40, mask = -1, boostEcl = true) { + if (!(QrCode.MIN_VERSION <= minVersion && minVersion <= maxVersion && maxVersion <= QrCode.MAX_VERSION) + || mask < -1 || mask > 7) + throw "Invalid value"; + // Find the minimal version number to use + let version; + let dataUsedBits; + for (version = minVersion;; version++) { + const dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8; // Number of data bits available + const usedBits = QrSegment.getTotalBits(segs, version); + if (usedBits <= dataCapacityBits) { + dataUsedBits = usedBits; + 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 + for (const newEcl of [Ecc.MEDIUM, Ecc.QUARTILE, Ecc.HIGH]) { // From low to high + if (boostEcl && dataUsedBits <= QrCode.getNumDataCodewords(version, newEcl) * 8) + ecl = newEcl; + } + // Concatenate all segments to create the data bit string + let bb = []; + for (const seg of segs) { + appendBits(seg.mode.modeBits, 4, bb); + appendBits(seg.numChars, seg.mode.numCharCountBits(version), bb); + for (const b of seg.getData()) + bb.push(b); + } + assert(bb.length == dataUsedBits); + // Add terminator and pad up to a byte if applicable + const dataCapacityBits = QrCode.getNumDataCodewords(version, ecl) * 8; + assert(bb.length <= dataCapacityBits); + appendBits(0, Math.min(4, dataCapacityBits - bb.length), bb); + appendBits(0, (8 - bb.length % 8) % 8, bb); + assert(bb.length % 8 == 0); + // Pad with alternating bytes until data capacity is reached + for (let padByte = 0xEC; bb.length < dataCapacityBits; padByte ^= 0xEC ^ 0x11) + appendBits(padByte, 8, bb); + // Pack bits into bytes in big endian + let dataCodewords = []; + while (dataCodewords.length * 8 < bb.length) + dataCodewords.push(0); + bb.forEach((b, i) => dataCodewords[i >>> 3] |= b << (7 - (i & 7))); + // Create the QR Code object + return new QrCode(version, ecl, dataCodewords, mask); + } + /*-- Accessor methods --*/ + // Returns the color of the module (pixel) at the given coordinates, which is false + // for light or true for dark. The top left corner has the coordinates (x=0, y=0). + // If the given coordinates are out of bounds, then false (light) is returned. + getModule(x, y) { + return 0 <= x && x < this.size && 0 <= y && y < this.size && this.modules[y][x]; + } + /*-- Private helper methods for constructor: Drawing function modules --*/ + // Reads this object's version field, and draws and marks all function modules. + drawFunctionPatterns() { + // Draw horizontal and vertical timing patterns + for (let i = 0; i < this.size; i++) { + this.setFunctionModule(6, i, i % 2 == 0); + this.setFunctionModule(i, 6, i % 2 == 0); + } + // Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules) + this.drawFinderPattern(3, 3); + this.drawFinderPattern(this.size - 4, 3); + this.drawFinderPattern(3, this.size - 4); + // Draw numerous alignment patterns + const alignPatPos = this.getAlignmentPatternPositions(); + const numAlign = alignPatPos.length; + for (let i = 0; i < numAlign; i++) { + for (let 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)) + this.drawAlignmentPattern(alignPatPos[i], alignPatPos[j]); + } + } + // Draw configuration data + this.drawFormatBits(0); // Dummy mask value; overwritten later in the constructor + this.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. + drawFormatBits(mask) { + // Calculate error correction code and pack bits + const data = this.errorCorrectionLevel.formatBits << 3 | mask; // errCorrLvl is uint2, mask is uint3 + let rem = data; + for (let i = 0; i < 10; i++) + rem = (rem << 1) ^ ((rem >>> 9) * 0x537); + const bits = (data << 10 | rem) ^ 0x5412; // uint15 + assert(bits >>> 15 == 0); + // Draw first copy + for (let i = 0; i <= 5; i++) + this.setFunctionModule(8, i, getBit(bits, i)); + this.setFunctionModule(8, 7, getBit(bits, 6)); + this.setFunctionModule(8, 8, getBit(bits, 7)); + this.setFunctionModule(7, 8, getBit(bits, 8)); + for (let i = 9; i < 15; i++) + this.setFunctionModule(14 - i, 8, getBit(bits, i)); + // Draw second copy + for (let i = 0; i < 8; i++) + this.setFunctionModule(this.size - 1 - i, 8, getBit(bits, i)); + for (let i = 8; i < 15; i++) + this.setFunctionModule(8, this.size - 15 + i, getBit(bits, i)); + this.setFunctionModule(8, this.size - 8, true); // Always dark + } + // Draws two copies of the version bits (with its own error correction code), + // based on this object's version field, iff 7 <= version <= 40. + drawVersion() { + if (this.version < 7) + return; + // Calculate error correction code and pack bits + let rem = this.version; // version is uint6, in the range [7, 40] + for (let i = 0; i < 12; i++) + rem = (rem << 1) ^ ((rem >>> 11) * 0x1F25); + const bits = this.version << 12 | rem; // uint18 + assert(bits >>> 18 == 0); + // Draw two copies + for (let i = 0; i < 18; i++) { + const color = getBit(bits, i); + const a = this.size - 11 + i % 3; + const b = Math.floor(i / 3); + this.setFunctionModule(a, b, color); + this.setFunctionModule(b, a, color); + } + } + // Draws a 9*9 finder pattern including the border separator, + // with the center module at (x, y). Modules can be out of bounds. + drawFinderPattern(x, y) { + for (let dy = -4; dy <= 4; dy++) { + for (let dx = -4; dx <= 4; dx++) { + const dist = Math.max(Math.abs(dx), Math.abs(dy)); // Chebyshev/infinity norm + const xx = x + dx; + const yy = y + dy; + if (0 <= xx && xx < this.size && 0 <= yy && yy < this.size) + this.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. + drawAlignmentPattern(x, y) { + for (let dy = -2; dy <= 2; dy++) { + for (let dx = -2; dx <= 2; dx++) + this.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. + setFunctionModule(x, y, isDark) { + this.modules[y][x] = isDark; + this.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. + addEccAndInterleave(data) { + const ver = this.version; + const ecl = this.errorCorrectionLevel; + if (data.length != QrCode.getNumDataCodewords(ver, ecl)) + throw "Invalid argument"; + // Calculate parameter numbers + const numBlocks = QrCode.NUM_ERROR_CORRECTION_BLOCKS[ecl.ordinal][ver]; + const blockEccLen = QrCode.ECC_CODEWORDS_PER_BLOCK[ecl.ordinal][ver]; + const rawCodewords = Math.floor(QrCode.getNumRawDataModules(ver) / 8); + const numShortBlocks = numBlocks - rawCodewords % numBlocks; + const shortBlockLen = Math.floor(rawCodewords / numBlocks); + // Split data into blocks and append ECC to each block + let blocks = []; + const rsDiv = QrCode.reedSolomonComputeDivisor(blockEccLen); + for (let i = 0, k = 0; i < numBlocks; i++) { + let dat = data.slice(k, k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1)); + k += dat.length; + const ecc = QrCode.reedSolomonComputeRemainder(dat, rsDiv); + if (i < numShortBlocks) + dat.push(0); + blocks.push(dat.concat(ecc)); + } + // Interleave (not concatenate) the bytes from every block into a single sequence + let result = []; + for (let i = 0; i < blocks[0].length; i++) { + blocks.forEach((block, j) => { + // Skip the padding byte in short blocks + if (i != shortBlockLen - blockEccLen || j >= numShortBlocks) + result.push(block[i]); + }); + } + assert(result.length == rawCodewords); + 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. + drawCodewords(data) { + if (data.length != Math.floor(QrCode.getNumRawDataModules(this.version) / 8)) + throw "Invalid argument"; + let i = 0; // Bit index into the data + // Do the funny zigzag scan + for (let right = this.size - 1; right >= 1; right -= 2) { // Index of right column in each column pair + if (right == 6) + right = 5; + for (let vert = 0; vert < this.size; vert++) { // Vertical counter + for (let j = 0; j < 2; j++) { + const x = right - j; // Actual x coordinate + const upward = ((right + 1) & 2) == 0; + const y = upward ? this.size - 1 - vert : vert; // Actual y coordinate + if (!this.isFunction[y][x] && i < data.length * 8) { + this.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/light by the constructor and are left unchanged by this method + } + } + } + assert(i == data.length * 8); + } + // 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. + applyMask(mask) { + if (mask < 0 || mask > 7) + throw "Mask value out of range"; + for (let y = 0; y < this.size; y++) { + for (let x = 0; x < this.size; x++) { + let 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 "Unreachable"; + } + if (!this.isFunction[y][x] && invert) + this.modules[y][x] = !this.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. + getPenaltyScore() { + let result = 0; + // Adjacent modules in row having same color, and finder-like patterns + for (let y = 0; y < this.size; y++) { + let runColor = false; + let runX = 0; + let runHistory = [0, 0, 0, 0, 0, 0, 0]; + for (let x = 0; x < this.size; x++) { + if (this.modules[y][x] == runColor) { + runX++; + if (runX == 5) + result += QrCode.PENALTY_N1; + else if (runX > 5) + result++; + } + else { + this.finderPenaltyAddHistory(runX, runHistory); + if (!runColor) + result += this.finderPenaltyCountPatterns(runHistory) * QrCode.PENALTY_N3; + runColor = this.modules[y][x]; + runX = 1; + } + } + result += this.finderPenaltyTerminateAndCount(runColor, runX, runHistory) * QrCode.PENALTY_N3; + } + // Adjacent modules in column having same color, and finder-like patterns + for (let x = 0; x < this.size; x++) { + let runColor = false; + let runY = 0; + let runHistory = [0, 0, 0, 0, 0, 0, 0]; + for (let y = 0; y < this.size; y++) { + if (this.modules[y][x] == runColor) { + runY++; + if (runY == 5) + result += QrCode.PENALTY_N1; + else if (runY > 5) + result++; + } + else { + this.finderPenaltyAddHistory(runY, runHistory); + if (!runColor) + result += this.finderPenaltyCountPatterns(runHistory) * QrCode.PENALTY_N3; + runColor = this.modules[y][x]; + runY = 1; + } + } + result += this.finderPenaltyTerminateAndCount(runColor, runY, runHistory) * QrCode.PENALTY_N3; + } + // 2*2 blocks of modules having same color + for (let y = 0; y < this.size - 1; y++) { + for (let x = 0; x < this.size - 1; x++) { + const color = this.modules[y][x]; + if (color == this.modules[y][x + 1] && + color == this.modules[y + 1][x] && + color == this.modules[y + 1][x + 1]) + result += QrCode.PENALTY_N2; + } + } + // Balance of dark and light modules + let dark = 0; + for (const row of this.modules) + dark = row.reduce((sum, color) => sum + (color ? 1 : 0), dark); + const total = this.size * this.size; // Note that size is odd, so dark/total != 1/2 + // Compute the smallest integer k >= 0 such that (45-5k)% <= dark/total <= (55+5k)% + const k = Math.ceil(Math.abs(dark * 20 - total * 10) / total) - 1; + assert(0 <= k && k <= 9); + result += k * QrCode.PENALTY_N4; + assert(0 <= result && result <= 2568888); // Non-tight upper bound based on default values of PENALTY_N1, ..., N4 + return result; + } + /*-- Private helper functions --*/ + // 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. + getAlignmentPatternPositions() { + if (this.version == 1) + return []; + else { + const numAlign = Math.floor(this.version / 7) + 2; + const step = (this.version == 32) ? 26 : + Math.ceil((this.version * 4 + 4) / (numAlign * 2 - 2)) * 2; + let result = [6]; + for (let pos = this.size - 7; result.length < numAlign; pos -= step) + result.splice(1, 0, pos); + return result; + } + } + // 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. + static getNumRawDataModules(ver) { + if (ver < QrCode.MIN_VERSION || ver > QrCode.MAX_VERSION) + throw "Version number out of range"; + let result = (16 * ver + 128) * ver + 64; + if (ver >= 2) { + const numAlign = Math.floor(ver / 7) + 2; + result -= (25 * numAlign - 10) * numAlign - 55; + if (ver >= 7) + result -= 36; + } + assert(208 <= result && result <= 29648); + 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. + static getNumDataCodewords(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]; + } + // Returns a Reed-Solomon ECC generator polynomial for the given degree. This could be + // implemented as a lookup table over all possible parameter values, instead of as an algorithm. + static reedSolomonComputeDivisor(degree) { + if (degree < 1 || degree > 255) + throw "Degree out of range"; + // Polynomial coefficients are 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]. + let result = []; + for (let i = 0; i < degree - 1; i++) + result.push(0); + result.push(1); // Start off with the monomial x^0 + // Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}), + // and drop the highest monomial term which is always 1x^degree. + // Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D). + let root = 1; + for (let i = 0; i < degree; i++) { + // Multiply the current product by (x - r^i) + for (let j = 0; j < result.length; j++) { + result[j] = QrCode.reedSolomonMultiply(result[j], root); + if (j + 1 < result.length) + result[j] ^= result[j + 1]; + } + root = QrCode.reedSolomonMultiply(root, 0x02); + } + return result; + } + // Returns the Reed-Solomon error correction codeword for the given data and divisor polynomials. + static reedSolomonComputeRemainder(data, divisor) { + let result = divisor.map(_ => 0); + for (const b of data) { // Polynomial division + const factor = b ^ result.shift(); + result.push(0); + divisor.forEach((coef, i) => result[i] ^= QrCode.reedSolomonMultiply(coef, factor)); + } + return result; + } + // 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. + static reedSolomonMultiply(x, y) { + if (x >>> 8 != 0 || y >>> 8 != 0) + throw "Byte out of range"; + // Russian peasant multiplication + let z = 0; + for (let i = 7; i >= 0; i--) { + z = (z << 1) ^ ((z >>> 7) * 0x11D); + z ^= ((y >>> i) & 1) * x; + } + assert(z >>> 8 == 0); + return z; + } + // Can only be called immediately after a light run is added, and + // returns either 0, 1, or 2. A helper function for getPenaltyScore(). + finderPenaltyCountPatterns(runHistory) { + const n = runHistory[1]; + assert(n <= this.size * 3); + const core = n > 0 && runHistory[2] == n && runHistory[3] == n * 3 && runHistory[4] == n && runHistory[5] == n; + return (core && runHistory[0] >= n * 4 && runHistory[6] >= n ? 1 : 0) + + (core && runHistory[6] >= n * 4 && runHistory[0] >= n ? 1 : 0); + } + // Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore(). + finderPenaltyTerminateAndCount(currentRunColor, currentRunLength, runHistory) { + if (currentRunColor) { // Terminate dark run + this.finderPenaltyAddHistory(currentRunLength, runHistory); + currentRunLength = 0; + } + currentRunLength += this.size; // Add light border to final run + this.finderPenaltyAddHistory(currentRunLength, runHistory); + return this.finderPenaltyCountPatterns(runHistory); + } + // Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore(). + finderPenaltyAddHistory(currentRunLength, runHistory) { + if (runHistory[0] == 0) + currentRunLength += this.size; // Add light border to initial run + runHistory.pop(); + runHistory.unshift(currentRunLength); + } +} +/*-- Constants and tables --*/ +// The minimum version number supported in the QR Code Model 2 standard. +QrCode.MIN_VERSION = 1; +// The maximum version number supported in the QR Code Model 2 standard. +QrCode.MAX_VERSION = 40; +// 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 + [-1, 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], + [-1, 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], + [-1, 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], + [-1, 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 + [-1, 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], + [-1, 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], + [-1, 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], + [-1, 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 +]; +// Appends the given number of low-order bits of the given value +// to the given buffer. Requires 0 <= len <= 31 and 0 <= val < 2^len. +function appendBits(val, len, bb) { + if (len < 0 || len > 31 || val >>> len != 0) + throw "Value out of range"; + for (let i = len - 1; i >= 0; i--) // Append bit by bit + bb.push((val >>> i) & 1); +} +// Returns true iff the i'th bit of x is set to 1. +function getBit(x, i) { + return ((x >>> i) & 1) != 0; +} +// Throws an exception if the given condition is false. +function assert(cond) { + if (!cond) + throw "Assertion error"; +} +/*---- 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. + */ +class QrSegment { + /*-- Constructor (low level) and fields --*/ + // Creates a new 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. + constructor( + // The mode indicator of this segment. + 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. + numChars, + // The data bits of this segment. Accessed through getData(). + bitData) { + this.mode = mode; + this.numChars = numChars; + this.bitData = bitData; + if (numChars < 0) + throw "Invalid argument"; + this.bitData = bitData.slice(); // Make defensive copy + } + /*-- Static factory functions (mid level) --*/ + // 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. + static makeBytes(data) { + let bb = []; + for (const b of data) + appendBits(b, 8, bb); + return new QrSegment(Mode.BYTE, data.length, bb); + } + // Returns a segment representing the given string of decimal digits encoded in numeric mode. + static makeNumeric(digits) { + if (!QrSegment.isNumeric(digits)) + throw "String contains non-numeric characters"; + let bb = []; + for (let i = 0; i < digits.length;) { // Consume up to 3 digits per iteration + const n = Math.min(digits.length - i, 3); + appendBits(parseInt(digits.substr(i, n), 10), n * 3 + 1, bb); + i += n; + } + return new QrSegment(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. + static makeAlphanumeric(text) { + if (!QrSegment.isAlphanumeric(text)) + throw "String contains unencodable characters in alphanumeric mode"; + let bb = []; + let i; + for (i = 0; i + 2 <= text.length; i += 2) { // Process groups of 2 + let temp = QrSegment.ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)) * 45; + temp += QrSegment.ALPHANUMERIC_CHARSET.indexOf(text.charAt(i + 1)); + appendBits(temp, 11, bb); + } + if (i < text.length) // 1 character remaining + appendBits(QrSegment.ALPHANUMERIC_CHARSET.indexOf(text.charAt(i)), 6, bb); + return new QrSegment(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. + static makeSegments(text) { + // Select the most efficient segment encoding automatically + if (text == "") + return []; + else if (QrSegment.isNumeric(text)) + return [QrSegment.makeNumeric(text)]; + else if (QrSegment.isAlphanumeric(text)) + return [QrSegment.makeAlphanumeric(text)]; + else + return [QrSegment.makeBytes(QrSegment.toUtf8ByteArray(text))]; + } + // Returns a segment representing an Extended Channel Interpretation + // (ECI) designator with the given assignment value. + static makeEci(assignVal) { + let bb = []; + if (assignVal < 0) + throw "ECI assignment value out of range"; + else if (assignVal < (1 << 7)) + appendBits(assignVal, 8, bb); + else if (assignVal < (1 << 14)) { + appendBits(0b10, 2, bb); + appendBits(assignVal, 14, bb); + } + else if (assignVal < 1000000) { + appendBits(0b110, 3, bb); + appendBits(assignVal, 21, bb); + } + else + throw "ECI assignment value out of range"; + return new QrSegment(Mode.ECI, 0, bb); + } + // Tests whether the given string can be encoded as a segment in numeric mode. + // A string is encodable iff each character is in the range 0 to 9. + static isNumeric(text) { + return QrSegment.NUMERIC_REGEX.test(text); + } + // Tests whether the given string can be encoded as a segment in alphanumeric mode. + // 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. + static isAlphanumeric(text) { + return QrSegment.ALPHANUMERIC_REGEX.test(text); + } + /*-- Methods --*/ + // Returns a new copy of the data bits of this segment. + getData() { + return this.bitData.slice(); // Make defensive copy + } + // (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. + static getTotalBits(segs, version) { + let result = 0; + for (const seg of segs) { + const 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.bitData.length; + } + return result; + } + // Returns a new array of bytes representing the given string encoded in UTF-8. + static toUtf8ByteArray(str) { + str = encodeURI(str); + let result = []; + for (let 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; + } +} +/*-- Constants --*/ +// Describes precisely all strings that are encodable in numeric mode. +QrSegment.NUMERIC_REGEX = /^[0-9]*$/; +// Describes precisely all strings that are encodable in alphanumeric mode. +QrSegment.ALPHANUMERIC_REGEX = /^[A-Z0-9 $%*+.\/:-]*$/; +// 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 ----*/ +/* + * The error correction level in a QR Code symbol. Immutable. + */ +class Ecc { + /*-- Constructor and fields --*/ + constructor( + // In the range 0 to 3 (unsigned 2-bit integer). + ordinal, + // (Package-private) In the range 0 to 3 (unsigned 2-bit integer). + formatBits) { + this.ordinal = ordinal; + this.formatBits = formatBits; + } +} +/*-- Constants --*/ +Ecc.LOW = new Ecc(0, 1); // The QR Code can tolerate about 7% erroneous codewords +Ecc.MEDIUM = new Ecc(1, 0); // The QR Code can tolerate about 15% erroneous codewords +Ecc.QUARTILE = new Ecc(2, 3); // The QR Code can tolerate about 25% erroneous codewords +Ecc.HIGH = new Ecc(3, 2); // The QR Code can tolerate about 30% erroneous codewords +/*---- Public helper enumeration ----*/ +/* + * Describes how a segment's data bits are interpreted. Immutable. + */ +class Mode { + /*-- Constructor and fields --*/ + constructor( + // The mode indicator bits, which is a uint4 value (range 0 to 15). + modeBits, + // Number of character count bits for three different version ranges. + numBitsCharCount) { + this.modeBits = modeBits; + this.numBitsCharCount = numBitsCharCount; + } + /*-- Method --*/ + // (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]. + numCharCountBits(ver) { + return this.numBitsCharCount[Math.floor((ver + 7) / 17)]; + } +} +/*-- Constants --*/ +Mode.NUMERIC = new Mode(0x1, [10, 12, 14]); +Mode.ALPHANUMERIC = new Mode(0x2, [9, 11, 13]); +Mode.BYTE = new Mode(0x4, [8, 16, 16]); +Mode.KANJI = new Mode(0x8, [8, 10, 12]); +Mode.ECI = new Mode(0x7, [0, 0, 0]); + +export { + QrCode, + Ecc, + QrSegment, + Mode, +}; \ No newline at end of file