private static bool TryReadIPv4MappedIPv6(Tokenizer tokenizer, out IpAddressV6 result)
{
ulong high = 0;
ulong low = 0;
byte segmentsRead = 0;
ParsedToken token;
// Read reverse, we're only interested in the IPv4 on the end
byte toRead = 4;
for (byte i = 0; i < toRead; i++)
{
token = tokenizer.ParseAndAdvanceReverse(false);
if (token.Type == TokenType.None)
{
break;
}
if (i > 0)
{
// The read token MUST be a dot
if (token.Type != TokenType.Dot)
{
result = default;
return(false);
}
// Advance once more
token = tokenizer.ParseAndAdvanceReverse(false);
}
// Read a number
if (token.Type == TokenType.Number)
{
BitUtilities.SetByte(ref low, ref high, (byte)(15 - i), token.Value);
segmentsRead++;
}
else
{
result = default;
return(false);
}
}
// Assert that the next tokens are [Double-/Colon, ffff, Colon]
token = tokenizer.ParseAndAdvanceReverse(false);
if (token.Type != TokenType.Colon)
{
result = default;
return(false);
}
token = tokenizer.ParseAndAdvanceReverse(true);
if (token.Type != TokenType.Number || token.Value != 0xffff)
{
result = default;
return(false);
}
token = tokenizer.ParseAndAdvanceReverse(false);
if (token.Type is not TokenType.Colon && token.Type is not TokenType.DoubleColon)
{
result = default;
return(false);
}
// Place 0xFFFF in the correct position
BitUtilities.SetTuplet(ref low, ref high, 5, 0xFFFF);
result = new IpAddressV6(high, low);
return(true);
}
