/// <summary>
/// Returns a C# type (or null if not found) for the given NBT tag type.
/// </summary>
private static Type GetTypeFromTag(NBT_Tag tag)
{
switch (tag)
{
case NBT_Tag.ByteSigned:
return(typeof(byte));
case NBT_Tag.Short:
return(typeof(short));
case NBT_Tag.Integer:
return(typeof(int));
case NBT_Tag.Long:
return(typeof(long));
case NBT_Tag.Float:
return(typeof(float));
case NBT_Tag.Double:
return(typeof(double));
case NBT_Tag.ByteArray:
return(typeof(byte[]));
case NBT_Tag.String:
return(typeof(string));
case NBT_Tag.IntArray:
return(typeof(int[]));
case NBT_Tag.LongArray:
return(typeof(long[]));
default:
return(null);
}
}
/// <summary>
/// Processes a single tag at the given location onto the destination object.
/// </summary>
private static void ProcessTag(byte[] data, ref int index, object typeObj, List <PropertyInfo> nbtProps)
{
//Are we done processing yet?
if (index == data.Length)
{
return;
}
//Is it an end compound? Then stop here.
if (index < 0)
{
throw new Exception("Invalid index for tag processing (<0).");
}
if ((NBT_Tag)data[index] == NBT_Tag.EndCompound)
{
index++;
return; //Stop processing here if it's the end of a compound.
}
//Get the name of the tag.
if (index + 2 >= data.Length)
{
throw new Exception("Invalid tag entrypoint at index " + index + " (no name length).");
}
int nameLen = BitConverter.ToInt16(data.Skip(index + 1).Take(2).Reverse().ToArray());
if (index + 2 + nameLen >= data.Length)
{
throw new Exception("Invalid tag entrypoint at index " + index + " (invalid name length).");
}
string name = Encoding.ASCII.GetString(data.Skip(index + 3).Take(nameLen).ToArray());
//Get all valid properties that could apply for this tag.
//If the property is using regex, then use IsMatch instead of literal name.
var possibleProps = new List <PropertyInfo>();
foreach (var prop in nbtProps)
{
var nbtAttr = (NBTItem)prop.GetCustomAttribute(typeof(NBTItem));
//Correct if it's a null name to name of the property.
if (nbtAttr.Name == null)
{
nbtAttr.Name = prop.Name;
}
//Check if it's a match, add to list if it is.
if (nbtAttr.Name == name || (nbtAttr.IsRegex && Regex.IsMatch(name, nbtAttr.Name)))
{
possibleProps.Add(prop);
}
}
//Whittle down the possible properties more by required type (if a specific one is required).
Type requiredType = GetTypeFromTag((NBT_Tag)data[index]);
//Cut by type (if a specific type is required).
if (requiredType != null)
{
for (int i = 0; i < possibleProps.Count; i++)
{
if (possibleProps[i].PropertyType != requiredType)
{
possibleProps.RemoveAt(i);
i--;
}
}
}
//Switch over the type and set the value.
int dataStart = index + 3 + nameLen;
var afterHeader = data.Skip(dataStart);
int nextIndex = -1;
NBT_Tag tag = (NBT_Tag)data[index];
switch (tag)
{
//Straightforward value type.s
case NBT_Tag.ByteSigned:
case NBT_Tag.Short:
case NBT_Tag.Integer:
case NBT_Tag.Long:
case NBT_Tag.Float:
case NBT_Tag.Double:
case NBT_Tag.ByteArray:
case NBT_Tag.String:
case NBT_Tag.IntArray:
case NBT_Tag.LongArray:
possibleProps.SetValue(typeObj, GetTagValue(tag, afterHeader, dataStart, ref nextIndex));
break;
//List of items.
case NBT_Tag.List:
ParseList(data, afterHeader, typeObj, possibleProps, dataStart, ref nextIndex);
break;
//Child compound.
case NBT_Tag.StartCompound:
//Consider only custom classes with NBTCompound tag.
for (int i = 0; i < possibleProps.Count; i++)
{
//Not custom/no tag?
if (possibleProps[i].PropertyType.Namespace.StartsWith("System") ||
possibleProps[i].PropertyType.GetCustomAttribute(typeof(NBTCompound)) == null)
{
continue;
}
//Get valid property data for destination type.
var childValidProps = possibleProps[i].PropertyType.GetProperties()
.Where(x => x.GetCustomAttribute(typeof(NBTItem)) != null);
//Recursively process NBT tags for child.
object childCompound = Activator.CreateInstance(possibleProps[i].PropertyType);
ProcessTag(data, ref dataStart, childCompound, childValidProps.ToList());
//Set in parent.
possibleProps[i].SetValue(typeObj, childCompound);
}
//If there are no possible properties, still recursively process on empty class.
if (possibleProps.Count == 0)
{
object childCompound = Activator.CreateInstance(typeof(NBTCompound));
ProcessTag(data, ref dataStart, childCompound, new List <PropertyInfo>());
}
//Set next index and break.
nextIndex = dataStart;
break;
}
//Process the next tag in the compound.
index = nextIndex;
ProcessTag(data, ref index, typeObj, nbtProps);
}
/// <summary>
/// Parses an NBT list tag given the starting data.
/// </summary>
private static void ParseList(byte[] data, IEnumerable <byte> afterHeader, object typeObj, List <PropertyInfo> possibleOriginal, int dataStart, ref int nextIndex)
{
//Get the length of the list.
int listLen = BitConverter.ToInt32(afterHeader.Skip(1).Take(4).Reverse().ToArray());
//If the list is zero length, just shuffle up the next index and return.
if (listLen == 0)
{
nextIndex = dataStart + 5;
return;
}
//Get the list type.
NBT_Tag tag = (NBT_Tag)afterHeader.ElementAt(0);
if (tag == NBT_Tag.EndCompound && listLen != 0)
{
throw new Exception("NBT list cannot be of type 'EndCompound' and have a non-zero length.");
}
Type listType = GetTypeFromTag(tag);
//Shallow copy the original list to not modify it.
List <PropertyInfo> possible = possibleOriginal.ShallowCopy();
//Whittle down the possible properties (must be lists with generic parameter (if found).
for (int i = 0; i < possible.Count; i++)
{
//Make sure it's a list. (todo: check)
if (possible[i].PropertyType.GetGenericTypeDefinition() != typeof(List <>) ||
!possible[i].PropertyType.IsGenericType ||
possible[i].PropertyType.GetGenericArguments().Length == 0)
{
possible.RemoveAt(i);
i--;
continue;
}
//Is the list generic of the right type (if type required).
if (listType != null && possible[i].PropertyType.GetGenericArguments()[0] != listType)
{
possible.RemoveAt(i);
i--;
continue;
}
}
//Make a list of the type and get values for the straightforward value types.
if (listType != null)
{
var lt = typeof(List <>).MakeGenericType(listType);
var list = (System.Collections.IList)Activator.CreateInstance(lt);
int startIndex = 5;
for (int i = 0; i < listLen; i++)
{
list.Add(GetTagValue(tag, afterHeader.Skip(startIndex), startIndex, ref startIndex));
}
//Set next, return the list.
nextIndex = dataStart + startIndex;
possible.SetValue(typeObj, list);
return;
}
//If it's a list of lists, give up (for now) and just emulate RDLP.
if (tag == NBT_Tag.List)
{
dataStart += 5;
for (int i = 0; i < listLen; i++)
{
ParseList(data, data.Skip(dataStart), new NBTCompound(), new List <PropertyInfo>(), dataStart, ref nextIndex);
dataStart = nextIndex;
}
}
//If it's a list of compounds, get the listed type from the NBTList tag.
if (tag == NBT_Tag.StartCompound)
{
foreach (var prop in possible)
{
//Yes, use it to get the types for the list indices.
listType = prop.PropertyType.GetGenericArguments()[0];
var lt = typeof(List <>).MakeGenericType(listType);
var list = (System.Collections.IList)Activator.CreateInstance(lt);
dataStart += 5;
for (int i = 0; i < listLen; i++)
{
//Create an instance of that type.
var listPropObj = Activator.CreateInstance(listType);
var nbtProps = listType.GetProperties()
.Where(x => x.GetCustomAttribute(typeof(NBTItem)) != null)
.ToList();
//Process all tags for the object.
ProcessTag(data, ref dataStart, listPropObj, nbtProps);
list.Add(listPropObj);
}
//Set list property.
prop.SetValue(typeObj, list);
}
//If no possible properties, just emulate with an empty class.
if (possible.Count == 0)
{
dataStart += 5;
for (int i = 0; i < listLen; i++)
{
//Create an instance of some class (doesn't really matter).
var listPropObj = Activator.CreateInstance(typeof(NBTCompound));
//Process all tags for the object.
ProcessTag(data, ref dataStart, listPropObj, new List <PropertyInfo>());
}
}
//Set the new starting index.
nextIndex = dataStart;
}
}
/// <summary>
/// Returns the value of a given tag given the type and starting data.
/// </summary>
private static object GetTagValue(NBT_Tag tag, IEnumerable <byte> afterHeader, int dataStart, ref int nextIndex)
{
switch (tag)
{
//One byte.
case NBT_Tag.ByteSigned:
nextIndex = dataStart + 1;
return(afterHeader.ElementAt(0));
//Short.
case NBT_Tag.Short:
nextIndex = dataStart + 2;
return(BitConverter.ToInt16(afterHeader.Take(2).Reverse().ToArray()));
//Integer (4 bytes, big endian).
case NBT_Tag.Integer:
nextIndex = dataStart + 4;
return(BitConverter.ToInt32(afterHeader.Take(4).Reverse().ToArray()));
//Long (8 bytes, big endian).
case NBT_Tag.Long:
nextIndex = dataStart + 8;
return(BitConverter.ToInt64(afterHeader.Take(8).Reverse().ToArray()));
//Float (4 byte IEEE-754 single precision).
case NBT_Tag.Float:
nextIndex = dataStart + 4;
return(BitConverter.ToSingle(afterHeader.Take(4).ToArray()));
//Double (8 byte IEEE-754 double precision).
case NBT_Tag.Double:
nextIndex = dataStart + 8;
return(BitConverter.ToDouble(afterHeader.Take(8).ToArray()));
//Byte array (length prefixed w/ signed 4-byte int).
case NBT_Tag.ByteArray:
int arrayLen = BitConverter.ToInt32(afterHeader.Take(4).Reverse().ToArray());
nextIndex = dataStart + 4 + arrayLen;
return(afterHeader.Skip(4).Take(arrayLen).ToArray());
//String (length prefixed with 2 byte ushort).
case NBT_Tag.String:
int strLen = BitConverter.ToUInt16(afterHeader.Take(2).Reverse().ToArray());
nextIndex = dataStart + 2 + strLen;
return(Encoding.UTF8.GetString(afterHeader.Skip(2).Take(strLen).ToArray()));
//Integer array (length prefixed with signed 4-byte int).
case NBT_Tag.IntArray:
int iArrLen = BitConverter.ToInt32(afterHeader.Take(4).Reverse().ToArray());
var ints = new List <int>();
for (int i = 0; i < iArrLen; i++)
{
ints.Add(BitConverter.ToInt32(afterHeader.Skip(4 + 4 * i).Take(4).Reverse().ToArray()));
}
nextIndex = dataStart + 4 + iArrLen * 4;
return(ints.ToArray());
//Long array (length prefixed with signed 4-byte int).
case NBT_Tag.LongArray:
int lArrLen = BitConverter.ToInt32(afterHeader.Take(4).Reverse().ToArray());
var longs = new List <long>();
for (int i = 0; i < lArrLen; i++)
{
longs.Add(BitConverter.ToInt64(afterHeader.Skip(4 + 8 * i).Take(8).Reverse().ToArray()));
}
nextIndex = dataStart + 4 + lArrLen * 8;
return(longs.ToArray());
default:
//Uh oh.
throw new Exception("Tag value cannot be grabbed for type '" + tag.ToString() + "'.");
}
}
