24 lines
916 B
TypeScript
24 lines
916 B
TypeScript
import assert from 'node:assert';
|
|
|
|
export class Frame {
|
|
static pack (head: Buffer, body: Buffer): Buffer {
|
|
const totalLength = 9 + head.length + body.length + 1;
|
|
const buffer = Buffer.allocUnsafe(totalLength);
|
|
buffer[0] = 0x28;
|
|
buffer.writeUInt32BE(head.length, 1);
|
|
buffer.writeUInt32BE(body.length, 5);
|
|
head.copy(buffer, 9);
|
|
body.copy(buffer, 9 + head.length);
|
|
buffer[totalLength - 1] = 0x29;
|
|
return buffer;
|
|
}
|
|
|
|
static unpack (frame: Buffer): [Buffer, Buffer] {
|
|
assert(frame[0] === 0x28 && frame[frame.length - 1] === 0x29, 'Invalid frame!');
|
|
const headLen = frame.readUInt32BE(1);
|
|
const bodyLen = frame.readUInt32BE(5);
|
|
// assert(frame.length === 9 + headLen + bodyLen + 1, `Frame ${frame.toString('hex')} length does not match head and body lengths!`);
|
|
return [frame.subarray(9, 9 + headLen), frame.subarray(9 + headLen, 9 + headLen + bodyLen)];
|
|
}
|
|
}
|