public bool TryGet(ref Position position, out Span <T> item, bool advance = false)
{
item = default(Span <T>);
if (_count == 0)
{
position = Position.AfterLast;
return(false);
}
if (position.Equals(Position.BeforeFirst))
{
if (advance)
{
position = Position.First;
}
return(false);
}
if (position.Equals(Position.AfterLast))
{
return(false);
}
item = this[position.IntegerPosition];
if (advance)
{
position.IntegerPosition++;
if (position.IntegerPosition >= _count)
{
position = Position.AfterLast;
}
}
return(true);
}
public static bool TryParseUInt32 <TSequence>(this TSequence bytes, EncodingData encoding, out uint value, out int consumed) where TSequence : ISpanSequence <byte>
{
Position position = Position.First;
Span <byte> first;
if (!bytes.TryGet(ref position, out first, advance: true))
{
throw new ArgumentException("bytes cannot be empty");
}
if (!PrimitiveParser.TryParseUInt32(first, EncodingData.Encoding.Utf8, out value, out consumed))
{
return(false); // TODO: maybe we should continue in some cases, e.g. if the first span ends in a decimal separator
// ... cont, maybe consumed could be set even if TryParse returns false
}
if (position.Equals(Position.AfterLast) || first.Length > consumed)
{
return(true);
}
Span <byte> second;
if (!bytes.TryGet(ref position, out second, advance: true))
{
throw new ArgumentException("bytes cannot be empty");
}
Span <byte> temp;
int numberOfBytesFromSecond = second.Length;
if (numberOfBytesFromSecond > 64)
{
numberOfBytesFromSecond = 64;
}
var tempBufferLength = first.Length + numberOfBytesFromSecond;
if (tempBufferLength > 128)
{
temp = new byte[tempBufferLength];
}
else
{
unsafe
{
byte *data = stackalloc byte[tempBufferLength];
temp = new Span <byte>(data, tempBufferLength);
}
}
first.CopyTo(temp);
second.Slice(0, numberOfBytesFromSecond).CopyTo(temp.Slice(first.Length));
if (!PrimitiveParser.TryParseUInt32(temp, EncodingData.Encoding.Utf8, out value, out consumed))
{
return(false);
}
if (position.Equals(Position.AfterLast) || temp.Length > consumed)
{
return(true);
}
throw new NotImplementedException();
}
