klf-200-api
Version:
This module provides a wrapper to the socket API of a Velux KLF-200 interface. You will need at least firmware 0.2.0.0.71 on your KLF interface for this library to work.
58 lines • 2.68 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.arrayToBitArray = exports.bitArrayToArray = void 0;
/**
* Converts a binary bit array to an array of numbers.
*
* @export
* @param {Buffer} bitArray Bytes where each bit is set for the corresponding number, e.g. the node ID.
* @returns {number[]} Returns an array of numbers with an entry for each set bit.
*/
function bitArrayToArray(bitArray) {
const resultArray = [];
for (let index = 0; index < bitArray.byteLength; index++) {
let arrayByte = bitArray.readUInt8(index);
// Skip bit operations if zero -> no bit is set
if (arrayByte !== 0) {
for (let bitIndex = 0; bitIndex < 8; bitIndex++) {
if ((arrayByte & 0x01) === 0x01) {
resultArray.push(index * 8 + bitIndex);
}
arrayByte = arrayByte >>> 1;
}
}
}
return resultArray;
}
exports.bitArrayToArray = bitArrayToArray;
/**
* Converts an array of numbers to a binary bit array.
*
* @export
* @param {number[]} numberArray Each number in the array corresponds to the bit that has to be set in the buffer.
* @param {number} bufferLength Length of the resulting buffer. This value will be ignored, if a destination buffer is provided.
* @param {Buffer} [destinationBuffer] Instead of creating a new buffer, the result can be written directly to an existing buffer.
* @returns {Buffer} Returns a new buffer with the bit array or the destination buffer, if a value for the destination buffer is provided.
*/
function arrayToBitArray(numberArray, bufferLength, destinationBuffer) {
const returnBuffer = destinationBuffer ? destinationBuffer : Buffer.alloc(bufferLength);
if (destinationBuffer) {
// Get the bufferLength from the destination buffer, if one is provided
bufferLength = destinationBuffer.byteLength;
}
const maxAllowedNumber = bufferLength * 8 - 1; // Max. allowed number is defined by the buffer size
// Fill buffer with zeros first
returnBuffer.fill(0);
// Write bits
for (let index = 0; index < numberArray.length; index++) {
// Check for valid number
const numberToWrite = numberArray[index];
if (numberToWrite < 0 || numberToWrite > maxAllowedNumber)
throw new Error("Number out of range.");
// Set bit
returnBuffer[Math.floor(numberToWrite / 8)] |= 1 << numberToWrite % 8; // numberToWrite / 8 = byte position (0-bufferLength), numberToWrite % 8 = bit position (0-7)
}
return returnBuffer;
}
exports.arrayToBitArray = arrayToBitArray;
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