blob: 1423356a3dd064713b7070bd71652912c41e62ac [file] [log] [blame]
// Copyright 2021 The Pigweed Authors
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
import * as protocol from './protocol';
import * as util from './util';
const FLAG_BYTE = Uint8Array.from([protocol.FLAG]);
export class Encoder {
constructor() {}
/** Encodes an HDLC UI-frame with a CRC-32 frame check sequence. */
uiFrame(address: number, data: Uint8Array): Uint8Array {
const addr = protocol.encodeAddress(address);
const frameControl = protocol.UI_FRAME_CONTROL;
const start = util.concatenate(addr, frameControl, data);
let frame = util.concatenate(start, protocol.frameCheckSequence(start));
frame = util.replace(frame, 0x7d, [0x7d, 0x5d]);
frame = util.replace(frame, 0x7e, [0x7d, 0x5e]);
return util.concatenate(FLAG_BYTE, frame, FLAG_BYTE);