99 lines
2.5 KiB
Dart
99 lines
2.5 KiB
Dart
import 'dart:typed_data';
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import 'package:msgpack_dart/msgpack_dart.dart';
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import 'package:es_compression/lz4.dart';
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final lz4Codec = Lz4Codec();
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Uint8List packPacket({
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required int ver,
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required int cmd,
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required int seq,
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required int opcode,
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required Map<String, dynamic> payload,
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}) {
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Uint8List payloadBytes = serialize(payload);
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bool isCompressed = false;
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if (payloadBytes.length >= 32) {
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final uncompressedSize = ByteData(4)
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..setUint32(0, payloadBytes.length, Endian.big);
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final compressedData = lz4Codec.encode(payloadBytes);
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final builder = BytesBuilder();
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builder.add(uncompressedSize.buffer.asUint8List());
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builder.add(compressedData);
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payloadBytes = builder.toBytes();
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isCompressed = true;
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}
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final header = ByteData(10);
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header.setUint8(0, ver);
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header.setUint16(1, cmd, Endian.big);
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header.setUint8(3, seq);
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header.setUint16(4, opcode, Endian.big);
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int packedLen = payloadBytes.length;
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if (isCompressed) {
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packedLen |= (1 << 24);
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}
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header.setUint32(6, packedLen, Endian.big);
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final builder = BytesBuilder();
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builder.add(header.buffer.asUint8List());
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builder.add(payloadBytes);
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return builder.toBytes();
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}
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Map<String, dynamic>? unpackPacket(Uint8List data) {
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if (data.length < 10) {
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print("Ошибка распаковки: Пакет слишком короткий для заголовка.");
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return null;
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}
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final byteData = data.buffer.asByteData(
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data.offsetInBytes,
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data.lengthInBytes,
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);
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final ver = byteData.getUint8(0);
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final cmd = byteData.getUint16(1, Endian.big);
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final seq = byteData.getUint8(3);
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final opcode = byteData.getUint16(4, Endian.big);
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final packedLen = byteData.getUint32(6, Endian.big);
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final compFlag = packedLen >> 24;
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final payloadLength = packedLen & 0x00FFFFFF;
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if (data.length < 10 + payloadLength) {
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print(
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"Ошибка распаковки: Фактическая длина пакета (${data.length}) меньше заявленной (${10 + payloadLength}).",
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);
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return null;
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}
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Uint8List payloadBytes = data.sublist(10, 10 + payloadLength);
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if (compFlag != 0) {
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try {
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final compressedData = payloadBytes.sublist(4);
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payloadBytes = Uint8List.fromList(lz4Codec.decode(compressedData));
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} catch (e) {
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print("Ошибка распаковки LZ4: $e");
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return null;
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}
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}
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final dynamic payload = deserialize(payloadBytes);
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return {
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"ver": ver,
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"cmd": cmd,
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"seq": seq,
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"opcode": opcode,
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"payload": payload,
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};
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}
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