initial commit

.eslintrc.js

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+module.exports = {
+  env: {
+    node: true,
+    commonjs: true,
+    es2021: true,
+  },
+  extends: ['airbnb', 'prettier'],
+  parserOptions: {
+    ecmaVersion: 'latest',
+  },
+  ignorePatterns: ['**/node_modules', '**/dist'],
+};

.gitignore

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+node_modules

.npmrc

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+git-tag-version=false

.nvmrc

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+v20.15.1

.prettierignore

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+*.md
+*.min.*
+dist

.prettierrc.js

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+module.exports = {
+  trailingComma: 'es5',
+  tabWidth: 2,
+  semi: true,
+  singleQuote: true,
+  bracketSameLine: true,
+  printWidth: 120,
+};

package.json

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+{
+  "name": "acn",
+  "version": "0.0.0",
+  "private": true,
+  "author": {
+    "name": "Joel Wetzell",
+    "email": "me@jwetzell.com",
+    "url": "https://jwetzell.com"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/jwetzell/acn-js.git"
+  },
+  "scripts": {
+    "lint:check": "eslint ./",
+    "format:check": "prettier ./ --check",
+    "format:write": "prettier ./ --write"
+  },
+  "workspaces": [
+    "packages/*"
+  ],
+  "devDependencies": {
+    "prettier": "3.3.3",
+    "eslint": "^8.48.0",
+    "eslint-config-airbnb": "^19.0.4",
+    "eslint-config-prettier": "^9.0.0"
+  }
+}

packages/acn/.gitignore

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+dist

packages/acn/package.json

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+{
+  "name": "@jwetzell/acn",
+  "version": "0.1.0",
+  "description": "",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "scripts": {
+    "prebuild": "rimraf dist",
+    "build": "tsc",
+    "prepublishOnly": "npm run build",
+    "pretest": "npm run build",
+    "test": "node --test --experimental-test-coverage"
+  },
+  "files": [
+    "dist"
+  ],
+  "author": {
+    "name": "Joel Wetzell",
+    "email": "me@jwetzell.com",
+    "url": "https://jwetzell.com"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/jwetzell/acn-js.git"
+  },
+  "license": "MIT",
+  "devDependencies": {
+    "@types/node": "22.7.5",
+    "rimraf": "6.0.1",
+    "typescript": "5.6.3"
+  }
+}

packages/acn/src/index.ts

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+export * from './models';
+export * from './udp';

packages/acn/src/models.ts

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+export type Protocols = {
+  SDT: 1;
+};
+
+export type UDPPreamble = {
+  preambleSize: number;
+  postambleSize: number;
+  packetIdentifier: string;
+};
+
+export type ACNPacket<PreambleType, PDUBlockType, PostambleType> = {
+  preamble: PreambleType;
+  pduBlock: PDUBlockType;
+  postamble: PostambleType;
+};
+
+export type RootLayerPDU = {
+  vector: number;
+  header: Uint8Array;
+  data: Uint8Array;
+};

packages/acn/src/pdu/index.ts

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+import rlp from './rlp';
+export default {
+  rlp,
+};

packages/acn/src/pdu/rlp.ts

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+import { RootLayerPDU } from '../models';
+
+function decode(bytes: Uint8Array): RootLayerPDU {
+  const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  const flags = view.getUint8(0) >> 4;
+  const lengthFlag = ((flags >> 3) & 0x1) === 1;
+  const vectorFlag = ((flags >> 2) & 0x1) === 1;
+
+  if (!vectorFlag) {
+    throw new Error('Root Layer PDU must have a vector');
+  }
+
+  const headerFlag = ((flags >> 1) & 0x1) === 1;
+
+  if (!headerFlag) {
+    throw new Error('Root Layer PDU must have a header');
+  }
+
+  const dataFlag = (flags & 0x1) === 1;
+
+  if (!dataFlag) {
+    // TODO(jwetzell): idk know if this is true
+    throw new Error('Root Layer PDU must have data');
+  }
+
+  const lengthH = view.getUint8(0) & 0x0f;
+  let lengthOffset = 1;
+  const lengthL = view.getUint8(lengthOffset);
+
+  let length = (lengthH << 8) + lengthL;
+
+  if (lengthFlag) {
+    lengthOffset += 1;
+    const lengthX = view.getUint8(lengthOffset);
+    length = (lengthH << 16) + (lengthL << 8) + lengthX;
+  }
+  let vectorOffset = lengthOffset + 1;
+
+  if (lengthFlag) {
+    vectorOffset += 1;
+  }
+
+  const vector = view.getUint32(vectorOffset);
+  const headerOffset = vectorOffset + 4;
+
+  const header = bytes.subarray(headerOffset, headerOffset + 16);
+  const dataOffset = headerOffset + 16;
+  // NOTE(jwetzell): flags/lengthH + lengthL + lengthX + vector + header
+  const dataLength = length - (1 + 1 + (lengthFlag ? 1 : 0) + 4 + 16);
+  const data = bytes.subarray(dataOffset, dataOffset + dataLength);
+
+  return {
+    vector,
+    header,
+    data,
+  };
+}
+
+export default {
+  decode,
+};

packages/acn/src/udp.ts

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+import { ACNPacket, RootLayerPDU, UDPPreamble } from './models';
+import pdu from './pdu';
+
+// ANSI E1.17 - 2015 (R2020) EPI 17
+export function decode(bytes: Uint8Array): ACNPacket<UDPPreamble, RootLayerPDU, undefined> {
+  if (bytes.byteLength < 16) {
+    throw new Error('ACN UDP packet must be at least 16 bytes long');
+  }
+
+  const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+
+  const preambleSize = view.getUint16(0, false);
+  if (preambleSize != 16) {
+    throw new Error('ACN UDP preamble size should 16');
+  }
+  const postambleSize = view.getUint16(2, false);
+  if (postambleSize > 0) {
+    throw new Error('ACN UDP postamble size should be 0');
+  }
+
+  const packetIdentifier = new TextDecoder().decode(bytes.subarray(4, preambleSize));
+
+  if (packetIdentifier !== 'ASC-E1.17\0\0\0') {
+    throw new Error('ACN Packet Identifier is incorrect');
+  }
+
+  const pduBlock = pdu.rlp.decode(bytes.subarray(preambleSize));
+
+  return {
+    preamble: {
+      preambleSize,
+      postambleSize,
+      packetIdentifier,
+    },
+    pduBlock,
+    postamble: undefined,
+  };
+}

packages/acn/tests/udp-decode.test.js

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+const { deepEqual, throws } = require('assert');
+const { describe, it } = require('node:test');
+const acn = require('../dist/index');
+
+const goodTests = [
+  {
+    description: 'simple udp pdu join',
+    bytes: new Uint8Array([
+      0, 16, 0, 0, 65, 83, 67, 45, 69, 49, 46, 49, 55, 0, 0, 0, 0x70, 72, 0, 0, 0, 1, 176, 171, 216, 42, 32, 210, 66,
+      64, 167, 205, 62, 73, 217, 153, 164, 229, 112, 50, 4, 73, 136, 131, 52, 255, 255, 74, 69, 176, 66, 102, 183, 33,
+      235, 216, 155, 0, 1, 244, 136, 0, 0, 0, 0, 244, 136, 0, 0, 244, 136, 1, 67, 216, 239, 192, 220, 207, 5, 0, 0, 2,
+      0, 10, 0, 20, 1, 44,
+    ]),
+    expected: {
+      preamble: {
+        preambleSize: 16,
+        postambleSize: 0,
+        packetIdentifier: 'ASC-E1.17\0\0\0',
+      },
+      pduBlock: {
+        vector: 1,
+        header: new Uint8Array([176, 171, 216, 42, 32, 210, 66, 64, 167, 205, 62, 73, 217, 153, 164, 229]),
+        data: new Uint8Array([
+          112, 50, 4, 73, 136, 131, 52, 255, 255, 74, 69, 176, 66, 102, 183, 33, 235, 216, 155, 0, 1, 244, 136, 0, 0, 0,
+          0, 244, 136, 0, 0, 244, 136, 1, 67, 216, 239, 192, 220, 207, 5, 0, 0, 2, 0, 10, 0, 20, 1, 44,
+        ]),
+      },
+      postamble: undefined,
+    },
+  },
+];
+
+const badTests = [
+  {
+    description: 'bad UDP packet size',
+    bytes: new Uint8Array([0, 16]),
+    throwsMessage: { name: /^Error$/, message: /ACN UDP packet must be at least 16 bytes long/ },
+  },
+  {
+    description: 'bad UDP preamble size',
+    bytes: new Uint8Array([
+      0, 20, 0, 0, 65, 83, 67, 45, 69, 49, 46, 49, 55, 0, 0, 0, 112, 72, 0, 0, 0, 1, 176, 171, 216, 42, 32, 210, 66, 64,
+      167, 205, 62, 73, 217, 153, 164, 229, 112, 50, 4, 73, 136, 131, 52, 255, 255, 74, 69, 176, 66, 102, 183, 33, 235,
+      216, 155, 0, 1, 244, 136, 0, 0, 0, 0, 244, 136, 0, 0, 244, 136, 1, 67, 216, 239, 192, 220, 207, 5, 0, 0, 2, 0, 10,
+      0, 20, 1, 44,
+    ]),
+    throwsMessage: { name: /^Error$/, message: /ACN UDP preamble size should 16/ },
+  },
+  {
+    description: 'bad UDP postamble size',
+    bytes: new Uint8Array([
+      0, 16, 0, 2, 65, 83, 67, 45, 69, 49, 46, 49, 55, 0, 0, 0, 112, 72, 0, 0, 0, 1, 176, 171, 216, 42, 32, 210, 66, 64,
+      167, 205, 62, 73, 217, 153, 164, 229, 112, 50, 4, 73, 136, 131, 52, 255, 255, 74, 69, 176, 66, 102, 183, 33, 235,
+      216, 155, 0, 1, 244, 136, 0, 0, 0, 0, 244, 136, 0, 0, 244, 136, 1, 67, 216, 239, 192, 220, 207, 5, 0, 0, 2, 0, 10,
+      0, 20, 1, 44,
+    ]),
+    throwsMessage: { name: /^Error$/, message: /ACN UDP postamble size should be 0/ },
+  },
+  {
+    description: 'bad ACN Packet Identifier',
+    bytes: new Uint8Array([
+      0, 16, 0, 0, 63, 83, 67, 45, 69, 49, 46, 49, 55, 0, 0, 0, 112, 72, 0, 0, 0, 1, 176, 171, 216, 42, 32, 210, 66, 64,
+      167, 205, 62, 73, 217, 153, 164, 229, 112, 50, 4, 73, 136, 131, 52, 255, 255, 74, 69, 176, 66, 102, 183, 33, 235,
+      216, 155, 0, 1, 244, 136, 0, 0, 0, 0, 244, 136, 0, 0, 244, 136, 1, 67, 216, 239, 192, 220, 207, 5, 0, 0, 2, 0, 10,
+      0, 20, 1, 44,
+    ]),
+    throwsMessage: { name: /^Error$/, message: /ACN Packet Identifier is incorrect/ },
+  },
+];
+
+describe('ACN Message Decoding Pass', () => {
+  goodTests.forEach((messageTest) => {
+    it(messageTest.description, () => {
+      const decoded = acn.decode(messageTest.bytes);
+      deepEqual(decoded, messageTest.expected);
+    });
+  });
+});
+
+describe('ACN Message Decoding Throws', () => {
+  badTests.forEach((messageTest) => {
+    it(messageTest.description, () => {
+      throws(() => {
+        acn.decode(messageTest.bytes);
+      }, messageTest.throwsMessage);
+    });
+  });
+});

packages/acn/tsconfig.json

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+{
+  "compilerOptions": {
+    "esModuleInterop": true,
+    "module": "commonjs",
+    "target": "ES2020",
+    "declaration": true,
+    "rootDir": "./src",
+    "strict": true,
+    "outDir": "dist"
+  },
+  "exclude": ["node_modules", "dist", "examples"]
+}