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