96 lines
2.4 KiB
Go
96 lines
2.4 KiB
Go
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package protocol
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import (
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"bytes"
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"compress/zlib"
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"encoding/binary"
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"io"
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"math"
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)
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func ZlibCompress(data []byte) []byte {
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var b bytes.Buffer
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w := zlib.NewWriter(&b)
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w.Write(data)
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w.Close()
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return b.Bytes()
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}
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// Codec Functions (migrated from main.go)
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func ReadVarint(r io.ByteReader) (uint64, error) {
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return binary.ReadUvarint(r)
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}
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func ReadVarintInt64(r io.ByteReader) (int64, error) {
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v, err := binary.ReadUvarint(r)
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return int64(v), err
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}
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func EncodeVarint(v uint64) []byte {
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buf := make([]byte, binary.MaxVarintLen64)
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n := binary.PutUvarint(buf, v)
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return buf[:n]
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}
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func EncodeDouble(v float64) []byte {
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buf := make([]byte, 8)
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binary.LittleEndian.PutUint64(buf, math.Float64bits(v))
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return buf
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}
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func SkipField(reader *bytes.Reader, wireType uint64) {
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switch wireType {
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case 0: // Varint
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ReadVarint(reader)
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case 1: // Fixed64
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reader.Seek(8, io.SeekCurrent)
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case 2: // Length-delimited
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length, _ := ReadVarint(reader)
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reader.Seek(int64(length), io.SeekCurrent)
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case 5: // Fixed32
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reader.Seek(4, io.SeekCurrent)
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}
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}
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// Helper to read a packet length (4 bytes, Big Endian) as per official protocol
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func ReadPacketLength(conn io.Reader) (uint32, error) {
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var length uint32
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err := binary.Read(conn, binary.BigEndian, &length)
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return length, err
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}
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// WrapPacket encapsulates a payload in the Message and Packet structure
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// 1. Message wrapper (Field 1: requestNumber, Field [requestNumber]: payload field)
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// 2. Packet wrapper (Field 1: packetID, Field 3: Message bytes)
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// 3. 4-byte Big Endian length prefix
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func WrapPacket(requestNumber int, payload []byte, packetID uint32) []byte {
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// 1. Wrap in Message
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msg := make([]byte, 0)
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// Field 1: request_number (Varint)
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msg = append(msg, 0x08)
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msg = append(msg, EncodeVarint(uint64(requestNumber))...)
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// Field [requestNumber]: The actual response payload
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msg = append(msg, EncodeVarint(uint64(uint32(requestNumber)<<3|2))...)
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msg = append(msg, EncodeVarint(uint64(len(payload)))...)
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msg = append(msg, payload...)
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// 2. Wrap in Packet
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packet := make([]byte, 0)
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// Field 1: Id (Varint)
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packet = append(packet, 0x08)
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packet = append(packet, EncodeVarint(uint64(packetID))...)
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// Field 3: Payload (Message)
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packet = append(packet, 0x1a)
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packet = append(packet, EncodeVarint(uint64(len(msg)))...)
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packet = append(packet, msg...)
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// 3. Add 4-byte length prefix
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final := make([]byte, 4)
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binary.BigEndian.PutUint32(final, uint32(len(packet)))
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final = append(final, packet...)
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return final
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}
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