public int ReadSignedInt(int numBits)
{
BitStreamUtil.AssertMaxBits(32, numBits);
// Just like PeekInt, but we cast to signed long before the shr because we need to sext
var result =
(int)
((long)(BitConverter.ToUInt64(Buffer, (Offset / 8) & ~3) << (8 * 8 - Offset % (8 * 4) - numBits)) >>
(8 * 8 - numBits));
Advance(numBits);
return(result);
}
public int ReadProtobufVarInt()
{
var availableBits = BitsInBuffer + SLED * 8 - Offset;
// Start by overflowingly reading 32 bits.
// Reading beyond the buffer contents is safe in this case,
// because the sled ensures that we stay inside of the buffer.
var buf = PeekInt(32, true);
// always take the first bytes; others if necessary
var result = buf & MSK_1;
BitStreamUtil.AssertMaxBits(availableBits, 1 * 8);
if ((buf & MSB_1) != 0)
{
result |= (buf & MSK_2) >> 1;
BitStreamUtil.AssertMaxBits(availableBits, 1 * 8);
if ((buf & MSB_2) != 0)
{
result |= (buf & MSK_3) >> 2;
BitStreamUtil.AssertMaxBits(availableBits, 2 * 8);
if ((buf & MSB_3) != 0)
{
result |= (buf & MSK_4) >> 3;
BitStreamUtil.AssertMaxBits(availableBits, 3 * 8);
if ((buf & MSB_4) != 0)
{
// dammit, it's too large (probably negative)
// fall back to the slow implementation, that's rare
return(BitStreamUtil.ReadProtobufVarIntStub(this));
}
Advance(4 * 8);
}
else
{
Advance(3 * 8);
}
}
else
{
Advance(2 * 8);
}
}
else
{
Advance(1 * 8);
}
return(unchecked ((int)result));
}
private uint PeekInt(int numBits, bool mayOverflow = false)
{
BitStreamUtil.AssertMaxBits(32, numBits);
Debug.Assert(mayOverflow || Offset + numBits <= BitsInBuffer + SLED * 8, "gg",
"This code just fell apart. We're all dead. Offset={0} numBits={1} BitsInBuffer={2}", Offset, numBits,
BitsInBuffer);
// _ xxxnno _
// _ xxxnno _
// _ xxxnno
return
((uint)
((BitConverter.ToUInt64(Buffer, (Offset / 8) & ~3) << (8 * 8 - Offset % (8 * 4) - numBits)) >>
(8 * 8 - numBits)));
}
public int ReadProtobufVarInt()
{
return(BitStreamUtil.ReadProtobufVarIntStub(this));
}
public byte ReadByte(int bits)
{
BitStreamUtil.AssertMaxBits(8, bits);
return((byte)ReadInt(bits));
}