zigbee-herdsman
Version:
An open source ZigBee gateway solution with node.js.
53 lines • 2.01 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.Frame = void 0;
const constants_1 = require("./constants");
class Frame {
type;
subsystem;
commandID;
data;
length;
fcs;
constructor(type, subsystem, commandID, data, length, fcs) {
this.type = type;
this.subsystem = subsystem;
this.commandID = commandID;
this.data = data;
this.length = length;
this.fcs = fcs;
}
toBuffer() {
const length = this.data.length;
const cmd0 = ((this.type << 5) & 0xe0) | (this.subsystem & 0x1f);
let payload = Buffer.from([constants_1.SOF, length, cmd0, this.commandID]);
payload = Buffer.concat([payload, this.data]);
const fcs = Frame.calculateChecksum(payload.slice(1, payload.length));
return Buffer.concat([payload, Buffer.from([fcs])]);
}
static fromBuffer(length, fcsPosition, buffer) {
const subsystem = buffer.readUInt8(constants_1.PositionCmd0) & 0x1f;
const type = (buffer.readUInt8(constants_1.PositionCmd0) & 0xe0) >> 5;
const commandID = buffer.readUInt8(constants_1.PositionCmd1);
const data = buffer.subarray(constants_1.DataStart, fcsPosition);
const fcs = buffer.readUInt8(fcsPosition);
// Validate the checksum to see if we fully received the message
const checksum = Frame.calculateChecksum(buffer.subarray(1, fcsPosition));
if (checksum === fcs) {
return new Frame(type, subsystem, commandID, data, length, fcs);
}
throw new Error("Invalid checksum");
}
static calculateChecksum(values) {
let checksum = 0;
for (const value of values) {
checksum ^= value;
}
return checksum;
}
toString() {
return `${this.length} - ${this.type} - ${this.subsystem} - ${this.commandID} - [${[...this.data]}] - ${this.fcs}`;
}
}
exports.Frame = Frame;
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