private long ReadInt64Impl(Stream stream, out int bytesRead, VarIntType varIntType)
{
long currentValue = 0;
var byteIndex = 0;
while (true)
{
var currentByte = stream.ReadByte();
if (currentByte == -1)
{
throw new EndOfStreamException();
}
(var byteValue, var readMore) = this.DecodeSingleByte((byte)currentByte, byteIndex++, varIntType);
currentValue |= byteValue;
if (!readMore)
{
break;
}
}
bytesRead = byteIndex;
return(currentValue);
}
private long ToInt64Impl(byte[] value, out int bytesRead, VarIntType varIntType)
{
long current = 0x00;
var byteIndex = 0;
while (true)
{
(var byteValue, var readMore) = this.DecodeSingleByte(value[byteIndex], byteIndex++, varIntType);
current |= byteValue;
if (!readMore)
{
break;
}
}
bytesRead = byteIndex;
return(current);
}
private int GetMaxLength(VarIntType type)
=> type switch
{
private (long byteValue, bool readMore) DecodeSingleByte(byte currentByte, int byteIndex, VarIntType varIntType)
{
if (byteIndex >= this.GetMaxLength(varIntType))
{
throw new FormatException($"{varIntType} cannot span over more than ten bytes.");
}
return(
byteValue : (currentByte & 0x7f) * (long)Math.Pow(0x80, byteIndex),
readMore : (currentByte & 0x80) != 0
);
}
