private byte[] ReallocateBuffer(int size)
{
Debug.Assert(_buffer.Length < size);
// We'll make this a nice round number.
size = IntHelpers.AlignUp(size, 8);
byte[] old = _buffer;
_buffer = new byte[size];
_handle.Free();
_handle = GCHandle.Alloc(_buffer, GCHandleType.Pinned);
return(old);
}
private void Align(int bits)
{
Debug.Assert(bits > 0);
if (bits == 1)
{
return;
}
int amount = (int)(IntHelpers.AlignUp(_bitOffset, bits) - _bitOffset);
if (amount != 0)
{
ReadBits(amount);
}
}
private int ReadBits(int bits)
{
int currentOffset = _bitOffset;
_bitOffset += bits;
int bufferLength = _bufferLength;
int bitLength = bufferLength * 8;
if (_bitOffset > bitLength)
{
int newBufferLength = IntHelpers.AlignUp(_bitOffset, 8) / 8;
FillBuffer(bufferLength, newBufferLength - bufferLength);
}
return(currentOffset);
}
private object ReadInteger(CtfInteger ctfInt)
{
if (ctfInt.Size > 64)
{
throw new NotImplementedException();
}
Align(ctfInt.Align);
int bitOffset = ReadBits(ctfInt.Size);
int byteOffset = bitOffset / 8;
bool fastPath = (_bitOffset % 8) == 0 && (ctfInt.Size % 8) == 0;
if (fastPath)
{
if (ctfInt.Size == 32)
{
if (ctfInt.Signed)
{
return(BitConverter.ToInt32(_buffer, byteOffset));
}
return(BitConverter.ToUInt32(_buffer, byteOffset));
}
if (ctfInt.Size == 8)
{
if (ctfInt.Signed)
{
return((sbyte)_buffer[byteOffset]);
}
return(_buffer[byteOffset]);
}
if (ctfInt.Size == 64)
{
if (ctfInt.Signed)
{
return(BitConverter.ToInt64(_buffer, byteOffset));
}
return(BitConverter.ToUInt64(_buffer, byteOffset));
}
Debug.Assert(ctfInt.Size == 16);
if (ctfInt.Signed)
{
return(BitConverter.ToInt16(_buffer, byteOffset));
}
return(BitConverter.ToUInt16(_buffer, byteOffset));
}
// Sloooow path for misaligned integers
int bits = ctfInt.Size;
ulong value = 0;
int byteLen = IntHelpers.AlignUp(bits, 8) / 8;
for (int i = 0; i < byteLen; i++)
{
value = unchecked ((value << 8) | _buffer[byteOffset + byteLen - i - 1]);
}
value >>= bitOffset;
value &= (ulong)((1 << bits) - 1);
if (ctfInt.Signed)
{
ulong signBit = (1u << (bits - 1));
if ((value & signBit) != 0)
{
value |= ulong.MaxValue << bits;
}
}
if (ctfInt.Size > 32)
{
if (ctfInt.Signed)
{
return((long)value);
}
return(value);
}
if (ctfInt.Size > 16)
{
if (ctfInt.Signed)
{
return((int)value);
}
return((uint)value);
}
if (ctfInt.Size > 8)
{
if (ctfInt.Signed)
{
return((short)value);
}
return((ushort)value);
}
if (ctfInt.Signed)
{
return((sbyte)value);
}
return((byte)value);
}
