rework header encode/decode

src/encoders/rttrp-header.ts

@@ -0,0 +1,45 @@
+const HEADER_SIZE = 18;
+
+export default (
+  floatSignature: number,
+  version: number,
+  packetID: number,
+  packetFormat: number,
+  context: number,
+  subModules: Uint8Array[],
+  isLittleEndian: boolean = false
+): Uint8Array => {
+  if (version !== 2) {
+    throw new Error('Only version 2 of the RTTrP header is currently supported');
+  }
+  const bytes = new Uint8Array(HEADER_SIZE);
+
+  let totalPacketSize = bytes.byteLength;
+  subModules.forEach((subModule) => {
+    totalPacketSize += subModule.length;
+  });
+
+  const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  let dataOffset = 0;
+
+  view.setUint16(dataOffset, 0x4154, isLittleEndian);
+  dataOffset += 2;
+  view.setUint16(dataOffset, floatSignature, isLittleEndian);
+  dataOffset += 2;
+  view.setUint16(dataOffset, version);
+  dataOffset += 2;
+
+  view.setUint32(dataOffset, packetID, isLittleEndian);
+  dataOffset += 4;
+
+  view.setUint8(dataOffset, packetFormat);
+  dataOffset += 1;
+  view.setUint16(dataOffset, totalPacketSize, isLittleEndian);
+  dataOffset += 2;
+  view.setUint32(dataOffset, context, isLittleEndian);
+  dataOffset += 4;
+  view.setUint8(dataOffset, subModules.length);
+  dataOffset += 1;
+
+  return bytes;
+};