#define UNSAFE_PUSH
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
namespace Tofvesson.Common
{
public sealed class BitWriter : IDisposable
{
private const int PREALLOC_COLLECT = 10;
private static readonly Queue<List<object>> listPool = new Queue<List<object>>();
private static readonly float[] holder_f = new float[1];
private static readonly double[] holder_d = new double[1];
private static readonly ulong[] holder_u = new ulong[1];
private static readonly uint[] holder_i = new uint[1];
private static readonly List<Type> supportedTypes = new List<Type>()
{
typeof(bool),
typeof(byte),
typeof(sbyte),
typeof(char),
typeof(short),
typeof(ushort),
typeof(int),
typeof(uint),
typeof(long),
typeof(ulong),
typeof(float),
typeof(double),
typeof(decimal)
};
private static readonly FieldInfo
dec_lo,
dec_mid,
dec_hi,
dec_flags;
static BitWriter()
{
dec_lo = typeof(decimal).GetField("lo", BindingFlags.NonPublic);
dec_mid = typeof(decimal).GetField("mid", BindingFlags.NonPublic);
dec_hi = typeof(decimal).GetField("hi", BindingFlags.NonPublic);
dec_flags = typeof(decimal).GetField("flags", BindingFlags.NonPublic);
for (int i = 0; i < PREALLOC_COLLECT; i++)
{
listPool.Enqueue(new List<object>());
}
}
private List<object> collect = null;
private bool tempAlloc = false;
/// <summary>
/// Allocates a new binary collector.
/// </summary>
public BitWriter()
{
if (listPool.Count == 0)
{
Debug.WriteLine("BitWriter: Optimized for "+ PREALLOC_COLLECT + " BitWriters. Have you forgotten to dispose?");
collect = new List<object>();
tempAlloc = true;
}
else
{
collect = listPool.Dequeue();
}
}
#if UNSAFE_PUSH
public
#else
private
# endif
void Push<T>(T b, bool known = false)
{
if (b == null) collect.Add(b);
else if (b is string || b.GetType().IsArray || IsSupportedType(b.GetType()))
collect.Add(b is string ? Encoding.UTF8.GetBytes(b as string) : b as object);
else
Debug.WriteLine("BitWriter: The type \"" + b.GetType() + "\" is not supported by the Binary Serializer. It will be ignored!");
}
// Public write methods to prevent errors when chaning types
public void WriteBool(bool b) => Push(b);
public void WriteFloat(float f) => Push(f);
public void WriteDouble(double d) => Push(d);
public void WriteByte(byte b) => Push(b);
public void WriteUShort(ushort s) => Push(s);
public void WriteUInt(uint i) => Push(i);
public void WriteULong(ulong l) => Push(l);
public void WriteSByte(sbyte b) => Push(ZigZagEncode(b, 8));
public void WriteShort(short s) => Push(ZigZagEncode(s, 8));
public void WriteInt(int i) => Push(ZigZagEncode(i, 8));
public void WriteLong(long l) => Push(ZigZagEncode(l, 8));
public void WriteString(string s) => Push(s);
public void WriteAlignBits() => Push<object>(null);
public void WriteFloatArray(float[] f, bool known = false) => PushArray(f, known);
public void WriteDoubleArray(double[] d, bool known = false) => PushArray(d, known);
public void WriteByteArray(byte[] b, bool known = false) => PushArray(b, known);
public void WriteUShortArray(ushort[] s, bool known = false) => PushArray(s, known);
public void WriteUIntArray(uint[] i, bool known = false) => PushArray(i, known);
public void WriteULongArray(ulong[] l, bool known = false) => PushArray(l, known);
public void WriteSByteArray(sbyte[] b, bool known = false) => PushArray(b, known);
public void WriteShortArray(short[] s, bool known = false) => PushArray(s, known);
public void WriteIntArray(int[] i, bool known = false) => PushArray(i, known);
public void WriteLongArray(long[] l, bool known = false) => PushArray(l, known);
#if UNSAFE_PUSH
public
#else
private
#endif
void PushArray<T>(T[] t, bool knownSize = false)
{
if (!knownSize) Push((uint)t.Length);
bool signed = IsSigned(t.GetType().GetElementType());
int size = Marshal.SizeOf(t.GetType().GetElementType());
foreach (T t1 in t) Push(signed ? (object)ZigZagEncode(t1 as long? ?? t1 as int? ?? t1 as short? ?? t1 as sbyte? ?? 0, size) : (object)t1);
}
// Actually serialize
public byte[] Finalize()
{
byte[] b = new byte[GetFinalizeSize()];
Finalize(ref b);
return b;
}
public long Finalize(ref byte[] buffer)
{
if(buffer == null)
{
Debug.WriteLine("BitWriter: no buffer provided");
return 0;
}
long bitCount = 0;
for (int i = 0; i < collect.Count; ++i) bitCount += collect[i] == null ? (8 - (bitCount % 8)) % 8 : GetBitCount(collect[i]);
if (buffer.Length < ((bitCount / 8) + (bitCount % 8 == 0 ? 0 : 1)))
{
Debug.WriteLine("BitWriter: The buffer size is not large enough");
return 0;
}
long bitOffset = 0;
bool isAligned = true;
foreach (var item in collect)
if (item == null)
{
bitOffset += (8 - (bitOffset % 8)) % 8;
isAligned = true;
}
else Serialize(item, buffer, ref bitOffset, ref isAligned);
collect.Clear(); // Allow GC to clean up any dangling references
return (bitCount / 8) + (bitCount % 8 == 0 ? 0 : 1);
}
// Compute output size (in bytes)
public long GetFinalizeSize()
{
long bitCount = 0;
for (int i = 0; i < collect.Count; ++i) bitCount += collect[i]==null ? (8 - (bitCount % 8)) % 8 : GetBitCount(collect[i]);
return ((bitCount / 8) + (bitCount % 8 == 0 ? 0 : 1));
}
// Serialization: Originally used dynamic, but due to the requirement of an adaptation using without dynamic,
// it has been completely retrofitted to not use dynamic
private static void Serialize<T>(T t, byte[] writeTo, ref long bitOffset, ref bool isAligned)
{
Type type = t.GetType();
bool size = false;
if (type.IsArray)
{
var array = t as Array;
Serialize((uint)array.Length, writeTo, ref bitOffset, ref isAligned);
foreach (var element in array)
Serialize(element, writeTo, ref bitOffset, ref isAligned);
}
else if (IsSupportedType(type))
{
long offset = t is bool ? 1 : BytesToRead(t) * 8;
if (type == typeof(bool))
{
WriteBit(writeTo, t as bool? ?? false, bitOffset);
bitOffset += offset;
isAligned = bitOffset % 8 == 0;
}
else if (type == typeof(decimal))
{
WriteDynamic(writeTo, (int)dec_lo.GetValue(t), 4, bitOffset, isAligned);
WriteDynamic(writeTo, (int)dec_mid.GetValue(t), 4, bitOffset + 32, isAligned);
WriteDynamic(writeTo, (int)dec_hi.GetValue(t), 4, bitOffset + 64, isAligned);
WriteDynamic(writeTo, (int)dec_flags.GetValue(t), 4, bitOffset + 96, isAligned);
bitOffset += offset;
}
else if ((size = type == typeof(float)) || type == typeof(double))
{
int bytes = size ? 4 : 8;
Array type_holder = size ? holder_f as Array : holder_d as Array; // Fetch the preallocated array
Array result_holder = size ? holder_i as Array : holder_u as Array;
lock (result_holder)
lock (type_holder)
{
// Clear artifacts
if (size) result_holder.SetValue(0U, 0);
else result_holder.SetValue(0UL, 0);
type_holder.SetValue(t, 0); // Insert the value to convert into the preallocated holder array
Buffer.BlockCopy(type_holder, 0, result_holder, 0, bytes); // Perform an internal copy to the byte-based holder
// Since floating point flag bits are seemingly the highest bytes of the floating point values
// and even very small values have them, we swap the endianness in the hopes of reducing the size
if(size) Serialize(BinaryHelpers.SwapEndian((uint)result_holder.GetValue(0)), writeTo, ref bitOffset, ref isAligned);
else Serialize(BinaryHelpers.SwapEndian((ulong)result_holder.GetValue(0)), writeTo, ref bitOffset, ref isAligned);
}
}
else
{
//bool signed = IsSigned(t.GetType());
ulong value;
/*if (signed)
{
Type t1 = t.GetType();
if (t1 == typeof(sbyte)) value = (byte)ZigZagEncode(t as sbyte? ?? 0, 1);
else if (t1 == typeof(short)) value = (ushort)ZigZagEncode(t as short? ?? 0, 2);
else if (t1 == typeof(int)) value = (uint)ZigZagEncode(t as int? ?? 0, 4);
else /*if (t1 == typeof(long)) value = (ulong)ZigZagEncode(t as long? ?? 0, 8);
}
else*/
if (t is byte)
{
WriteByte(writeTo, t as byte? ?? 0, bitOffset, isAligned);
bitOffset += 8;
return;
}
else if (t is ushort) value = t as ushort? ?? 0;
else if (t is uint) value = t as uint? ?? 0;
else /*if (t is ulong)*/ value = t as ulong? ?? 0;
// VarInt implementation
if (value <= 240) WriteByte(writeTo, (byte)value, bitOffset, isAligned);
else if (value <= 2287)
{
WriteByte(writeTo, (value - 240) / 256 + 241, bitOffset, isAligned);
WriteByte(writeTo, (value - 240) % 256, bitOffset + 8, isAligned);
}
else if (value <= 67823)
{
WriteByte(writeTo, 249, bitOffset, isAligned);
WriteByte(writeTo, (value - 2288) / 256, bitOffset + 8, isAligned);
WriteByte(writeTo, (value - 2288) % 256, bitOffset + 16, isAligned);
}
else
{
WriteByte(writeTo, value & 255, bitOffset + 8, isAligned);
WriteByte(writeTo, (value >> 8) & 255, bitOffset + 16, isAligned);
WriteByte(writeTo, (value >> 16) & 255, bitOffset + 24, isAligned);
if (value > 16777215)
{
WriteByte(writeTo, (value >> 24) & 255, bitOffset + 32, isAligned);
if (value > 4294967295)
{
WriteByte(writeTo, (value >> 32) & 255, bitOffset + 40, isAligned);
if (value > 1099511627775)
{
WriteByte(writeTo, (value >> 40) & 55, bitOffset + 48, isAligned);
if (value > 281474976710655)
{
WriteByte(writeTo, (value >> 48) & 255, bitOffset + 56, isAligned);
if (value > 72057594037927935)
{
WriteByte(writeTo, 255, bitOffset, isAligned);
WriteByte(writeTo, (value >> 56) & 255, bitOffset + 64, isAligned);
}
else WriteByte(writeTo, 254, bitOffset, isAligned);
}
else WriteByte(writeTo, 253, bitOffset, isAligned);
}
else WriteByte(writeTo, 252, bitOffset, isAligned);
}
else WriteByte(writeTo, 251, bitOffset, isAligned);
}
else WriteByte(writeTo, 250, bitOffset, isAligned);
}
bitOffset += BytesToRead(value) * 8;
}
}
}
// Write oddly bounded data
private static byte Read7BitRange(byte higher, byte lower, int bottomBits) => (byte)((higher << bottomBits) & (lower & (0xFF << (8-bottomBits))));
private static byte ReadNBits(byte from, int offset, int count) => (byte)(from & ((0xFF >> (8-count)) << offset));
// Check if type is signed (int, long, etc)
private static bool IsSigned(Type t) => t == typeof(sbyte) || t == typeof(short) || t == typeof(int) || t == typeof(long);
private static Type GetUnsignedType(Type t) =>
t == typeof(sbyte) ? typeof(byte) :
t == typeof(short) ? typeof(ushort) :
t == typeof(int) ? typeof(uint) :
t == typeof(long) ? typeof(ulong) :
null;
// Encode signed values in a way that preserves magnitude
private static ulong ZigZagEncode(long d, int bytes) => (ulong)(((d >> (bytes * 8 - 1))&1) | (d << 1));
// Gets the amount of bits required to serialize a given value
private static long GetBitCount<T>(T t)
{
Type type = t.GetType();
long count = 0;
if (type.IsArray)
{
Type elementType = type.GetElementType();
count += BytesToRead((t as Array).Length) * 8; // Int16 array size. Arrays shouldn't be syncing more than 65k elements
if (elementType == typeof(bool)) count += (t as Array).Length;
else
foreach (var element in t as Array)
count += GetBitCount(element);
}
else if (IsSupportedType(type))
{
long ba = t is bool ? 1 : BytesToRead(t)*8;
if (ba == 0) count += Encoding.UTF8.GetByteCount(t as string);
else if (t is bool || t is decimal) count += ba;
else count += BytesToRead(t) * 8;
}
//else
// Debug.LogWarning("MLAPI: The type \"" + b.GetType() + "\" is not supported by the Binary Serializer. It will be ignored");
return count;
}
// Write methods
private static void WriteBit(byte[] b, bool bit, long index)
=> b[index / 8] = (byte)((b[index / 8] & ~(1 << (int)(index % 8))) | (bit ? 1 << (int)(index % 8) : 0));
private static void WriteByte(byte[] b, ulong value, long index, bool isAligned) => WriteByte(b, (byte)value, index, isAligned);
private static void WriteByte(byte[] b, byte value, long index, bool isAligned)
{
if (isAligned) b[index / 8] = value;
else
{
int byteIndex = (int)(index / 8);
int shift = (int)(index % 8);
byte upper_mask = (byte)(0xFF << shift);
b[byteIndex] = (byte)((b[byteIndex] & (byte)~upper_mask) | (value << shift));
b[byteIndex + 1] = (byte)((b[byteIndex + 1] & upper_mask) | (value >> (8 - shift)));
}
}
private static void WriteDynamic(byte[] b, int value, int byteCount, long index, bool isAligned)
{
for (int i = 0; i < byteCount; ++i)
WriteByte(b, (byte)((value >> (8 * i)) & 0xFF), index + (8 * i), isAligned);
}
private static int BytesToRead(object i)
{
if (i is byte) return 1;
bool size;
ulong integer;
if (i is decimal) return BytesToRead((int)dec_flags.GetValue(i)) + BytesToRead((int)dec_lo.GetValue(i)) + BytesToRead((int)dec_mid.GetValue(i)) + BytesToRead((int)dec_hi.GetValue(i));
if ((size = i is float) || i is double)
{
int bytes = size ? 4 : 8;
Array type_holder = size ? holder_f as Array : holder_d as Array; // Fetch the preallocated array
Array result_holder = size ? holder_i as Array : holder_u as Array;
lock (result_holder)
lock (type_holder)
{
// Clear artifacts
if (size) result_holder.SetValue(0U, 0);
else result_holder.SetValue(0UL, 0);
type_holder.SetValue(i, 0); // Insert the value to convert into the preallocated holder array
Buffer.BlockCopy(type_holder, 0, result_holder, 0, bytes); // Perform an internal copy to the byte-based holder
if(size) integer = BinaryHelpers.SwapEndian((uint)result_holder.GetValue(0));
else integer = BinaryHelpers.SwapEndian((ulong)result_holder.GetValue(0));
}
}
else integer = i as ulong? ?? i as uint? ?? i as ushort? ?? i as byte? ?? 0;
return
integer <= 240 ? 1 :
integer <= 2287 ? 2 :
integer <= 67823 ? 3 :
integer <= 16777215 ? 4 :
integer <= 4294967295 ? 5 :
integer <= 1099511627775 ? 6 :
integer <= 281474976710655 ? 7 :
integer <= 72057594037927935 ? 8 :
9;
}
// Supported datatypes for serialization
private static bool IsSupportedType(Type t) => supportedTypes.Contains(t);
// Creates a weak reference to the allocated collector so that reuse may be possible
public void Dispose()
{
if (!tempAlloc)
{
collect.Clear();
listPool.Enqueue(collect);
}
collect = null; //GC picks this
}
}
}