136 lines
4.2 KiB
C#
136 lines
4.2 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Linq;
|
|
using System.Text;
|
|
using System.Threading.Tasks;
|
|
using Glove;
|
|
|
|
namespace SockScape {
|
|
class Packet {
|
|
private static readonly byte[] MagicNumber = { 0xF0, 0x9F, 0xA6, 0x91 };
|
|
|
|
public static Packet FromBytes(byte[] raw) {
|
|
if(raw.Length < 7)
|
|
return null;
|
|
|
|
Packet packet = new Packet();
|
|
|
|
if(!raw.Subset(0, 4).SequenceEqual(MagicNumber))
|
|
return null;
|
|
|
|
packet.Id = raw[4];
|
|
var regionCount = raw[5];
|
|
var regionLengths = new List<uint>();
|
|
var headerPtr = 6;
|
|
for(var i = 0; i < regionCount; ++i) {
|
|
regionLengths.Add(0);
|
|
var first = raw[headerPtr];
|
|
if(first < 254) {
|
|
regionLengths[i] = first;
|
|
++headerPtr;
|
|
} else if(first == 254) {
|
|
if(headerPtr + 3 < raw.Length)
|
|
return null;
|
|
regionLengths[i] = raw.Subset(headerPtr + 1, 2).UnpackUInt16();
|
|
headerPtr += 3;
|
|
} else {
|
|
if(headerPtr + 5 < raw.Length)
|
|
return null;
|
|
regionLengths[i] = raw.Subset(headerPtr + 1, 4).UnpackUInt32();
|
|
headerPtr += 5;
|
|
}
|
|
|
|
if(headerPtr > raw.Length)
|
|
return null;
|
|
}
|
|
|
|
if(headerPtr + regionLengths.Sum(x => x) > raw.Length)
|
|
return null;
|
|
|
|
long bodyPtr = headerPtr;
|
|
foreach(var regionLength in regionLengths) {
|
|
// FLAG this could fail if one region exceeds 2^31-1 in size, check later
|
|
packet.Regions.Add(raw.Subset((int)bodyPtr, (int)regionLength));
|
|
bodyPtr += regionLength;
|
|
}
|
|
|
|
return packet;
|
|
}
|
|
|
|
private List<byte[]> Regions = new List<byte[]>();
|
|
public int Id { get; private set; }
|
|
public int RegionCount {
|
|
get => Regions.Count;
|
|
}
|
|
|
|
protected Packet() { }
|
|
|
|
public Packet(int id, params object[] regions) {
|
|
Id = id;
|
|
|
|
foreach(var region in regions)
|
|
AddRegion(region);
|
|
}
|
|
|
|
public Region this[int i] {
|
|
get => new Region(Regions[i]);
|
|
}
|
|
|
|
public Packet AddRegion(object region) {
|
|
if(region.GetType() == typeof(byte[]))
|
|
Regions.Add((byte[])region);
|
|
else if(region.GetType() == typeof(string))
|
|
Regions.Add(((string)region).GetBytes());
|
|
|
|
return this;
|
|
}
|
|
|
|
public byte[] GetBytes() {
|
|
var header = new List<byte>();
|
|
header.AddRange(MagicNumber);
|
|
header.Add((byte)Id);
|
|
header.Add((byte)RegionCount);
|
|
|
|
IEnumerable<byte> body = new byte[0];
|
|
foreach(var region in Regions) {
|
|
if(region.Length < 0xFE)
|
|
header.Add((byte)region.Length);
|
|
else if(region.Length <= 0xFFFF) {
|
|
header.Add(0xFE);
|
|
header.AddRange(((UInt16)region.Length).Pack());
|
|
} else {
|
|
header.Add(0xFF);
|
|
header.AddRange(region.Length.Pack());
|
|
}
|
|
|
|
body = body.Concat(region);
|
|
}
|
|
|
|
return header.Concat(body).ToArray();
|
|
}
|
|
|
|
public class Region {
|
|
public byte[] Data { get; private set; }
|
|
|
|
public Region(byte[] data) {
|
|
Data = data;
|
|
}
|
|
|
|
public static implicit operator byte[] (Region region) => region.Data;
|
|
public string Bytes {
|
|
get => this;
|
|
}
|
|
|
|
public static implicit operator string(Region region) {
|
|
try {
|
|
return Encoding.UTF8.GetString(region.Data);
|
|
} catch {
|
|
return Encoding.ASCII.GetString(region.Data);
|
|
}
|
|
}
|
|
public string Str {
|
|
get => this;
|
|
}
|
|
}
|
|
}
|
|
}
|