System.Text.RegularExpressions.Interpreter.IsPosition C# (CSharp) Метод

		private bool IsPosition (Position pos, int ptr) {
			switch (pos) {
			case Position.Start: case Position.StartOfString:
				return ptr == 0;

			case Position.StartOfLine:
				return ptr == 0 || text[ptr - 1] == '\n';
				
			case Position.StartOfScan:
				return ptr == scan_ptr;
			
			case Position.End:
				return ptr == text_end ||
					(ptr == text_end - 1 && text[ptr] == '\n');

			case Position.EndOfLine:
				return ptr == text_end || text[ptr] == '\n';
				
			case Position.EndOfString:
				return ptr == text_end;
				
			case Position.Boundary:
				if (text_end == 0)
					return false;

				if (ptr == 0)
					return IsWordChar (text[ptr]);
				else if (ptr == text_end)
					return IsWordChar (text[ptr - 1]);
				else
					return IsWordChar (text[ptr]) != IsWordChar (text[ptr - 1]);

			case Position.NonBoundary:
				if (text_end == 0)
					return false;

				if (ptr == 0)
					return !IsWordChar (text[ptr]);
				else if (ptr == text_end)
					return !IsWordChar (text[ptr - 1]);
				else
					return IsWordChar (text[ptr]) == IsWordChar (text[ptr - 1]);
			
			default:
				return false;
			}
		}