private static TagParserResult ParseTag(string tag, bool throwException)
{
var result = new TagParserResult();
using (var buffer = MemoryPool <char> .Shared.Rent(tag.Length))
{
var input = buffer.Memory.Slice(0, tag.Length).Span;
tag.AsSpan().ToLowerInvariant(input);
var indexStart = 0;
var state = TagParserState.Area;
ReadOnlySpan <char> type = null;
for (var i = 0; i < input.Length; i++)
{
if (input[i] != '.' && input[i] != ',')
{
continue;
}
Parse(tag, ref result, ref indexStart, ref state, ref type, input.Slice(indexStart, i - indexStart), i, throwException);
}
Parse(tag, ref result, ref indexStart, ref state, ref type, input.Slice(indexStart), input.Length - 1, throwException);
state = TagParserState.TypeValidation;
Parse(tag, ref result, ref indexStart, ref state, ref type, input, input.Length - 1, throwException);
if (state == TagParserState.Success)
{
result.ErrorState = TagParserState.Success;
}
}
return(result);
}
private static void Parse(string tag, ref TagParserResult result, ref int indexStart, ref TagParserState state, ref ReadOnlySpan <char> type, ReadOnlySpan <char> data, int index, bool throwException = false)
{
if (!TryExtractData(ref result, data, ref indexStart, ref state, ref type, index) && throwException)
{
result.ErrorState = state;
ThrowHelper.ThrowTagParseException(TagParserState.Area, data.ToString(), tag);
}
}
// DB1.80000,x,1
public static bool TryParseTag(string tag, out TagParserResult result)
{
result = ParseTag(tag, false);
return(result.ErrorState == TagParserState.Success);
}
private static bool TryExtractData(ref TagParserResult result, ReadOnlySpan <char> input, ref int indexStart, ref TagParserState state, ref ReadOnlySpan <char> type, int i)
{
switch (state)
{
case TagParserState.Area:
{
if (TryDetectArea(input, out var selector, out var db))
{
result.Area = selector;
result.DbNumber = db;
indexStart = i + 1;
state = TagParserState.Offset;
return(true);
}
}
break;
case TagParserState.Offset:
{
// TODO: !!!!!!!
#if SPANSUPPORT
if (int.TryParse(input, out var offset))
#else
if (TryConvertSpanToInt32(input, out var offset))
#endif
{
result.Offset = offset;
indexStart = i + 1;
state = TagParserState.Type;
return(true);
}
}
break;
case TagParserState.Type:
{
type = input;
state = TagParserState.NumberOfItems;
indexStart = i + 1;
return(true);
}
case TagParserState.NumberOfItems:
{
if (input.IsEmpty)
{
return(true);
}
// TODO: !!!!!!!
#if SPANSUPPORT
if (ushort.TryParse(input, out var length))
#else
if (TryConvertSpanToUShort(input, out var length))
#endif
{
result.Length = length;
state = TagParserState.TypeValidation;
return(true);
}
}
break;
case TagParserState.TypeValidation:
{
if (result.Length <= 0)
{
result.Length = 1;
}
var offset = result.Offset;
var length = result.Length;
if (!type.IsEmpty && TryDetectTypes(type, ref length, ref offset, out var vtype, out var rType, out var unicode))
{
result.Length = length;
result.Offset = offset;
result.VarType = vtype;
result.ResultType = rType;
result.Encoding = unicode;
indexStart = i + 1;
state = TagParserState.Success;
return(true);
}
}
break;
case TagParserState.Success:
return(true);
}
return(false);
}
