Start to migrate delimiter code to common helper.

IOStreams/OStreamable.test/0.cc

@@ -27,7 +27,7 @@ namespace
 
 
 	auto
-	stringify( const Agg &agg, const char delim )
+	stringify( const Agg &agg, const std::string delim )
 	{
 		std::ostringstream oss;
 		oss << Alepha::IOStreams::setFieldDelimiter( delim );
@@ -44,7 +44,9 @@ static auto init= Alepha::Utility::enroll <=[]
 	"Simple OStream"_test <=TableTest< stringify >
 	::Cases
 	{
-		{ "smoke test", { { 1, 2, 3 }, '\t' }, { "1\t2\t3" } },
-		{ "smoke test", { { 1, 2, 3 }, ',' }, { "1,2,3" } },
+		{ "smoke test", { { 1, 2, 3 }, "\t" }, { "1\t2\t3" } },
+		{ "smoke test", { { 1, 2, 3 }, "," }, { "1,2,3" } },
+		{ "smoke test", { { 1, 2, 3 }, ";;" }, { "1;;2;;3" } },
+		{ "smoke test", { { 1, 2, 3 }, ", " }, { "1, 2, 3" } },
 	};
 };

IOStreams/StreamState.h

@@ -0,0 +1,101 @@
+static_assert( __cplusplus > 2020'00 );
+
+#pragma once
+
+#include <ios>
+#include <exception>
+
+#include <Alepha/Alepha.h>
+
+namespace Alepha::Hydrogen::IOStreams  ::detail::  stream_state
+{
+	inline namespace exports
+	{
+		template< typename Tag, typename Type >
+		class StreamState;
+	}
+
+	template< typename Tag, typename Type >
+	class exports::StreamState
+	{
+		private:
+			static auto
+			index()
+			{
+				static const auto rv= std::ios::xalloc();
+				return rv;
+			}
+
+			static Type *&
+			get_ptr( std::ios_base &ios )
+			{
+				return reinterpret_cast< Type *& >( ios.pword( index() ) );
+			}
+
+			static void
+			destroy( std::ios_base &ios )
+			{
+				delete get_ptr( ios );
+				get_ptr( ios )= nullptr;
+			}
+
+			static void
+			callback_impl( const std::ios_base::event event, std::ios_base &ios, const int idx )
+			{
+				if( idx != index() ) throw std::logic_error( "Wrong index." );
+
+				if( event == std::ios_base::erase_event ) destroy( ios );
+				else if( event == std::ios_base::imbue_event )
+				{
+					// Nothing to do... until I develop locale support.
+				}
+				else if( event == std::ios_base::copyfmt_event )
+				{
+					get_ptr( ios )= new Type{ get( ios ) };
+				}
+			}
+
+			static void
+			callback( const std::ios_base::event event, std::ios_base &ios, const int idx ) noexcept
+			{
+				return callback_impl( event, ios, idx );
+			}
+
+			static void
+			init( std::ios_base &ios )
+			{
+				if( not ios.iword( index() ) )
+				{
+					ios.iword( index() )= 1;
+					ios.register_callback( callback, index() );
+				}
+				auto *&ptr= get_ptr( ios );
+				if( not ptr ) ptr= new Type{};
+			}
+
+		public:
+			static Type &
+			get( std::ios_base &ios )
+			{
+				init( ios );
+				return *get_ptr( ios );
+			}
+
+			struct Setter
+			{
+				const Type val;
+
+				friend std::ostream &
+				operator << ( std::ostream &os, const Setter &s )
+				{
+					StreamState::get( os )= s.val;
+					return os;
+				}
+			};
+	};
+}
+
+namespace Alepha::Hydrogen::IOStreams::inline exports::inline stream_state
+{
+	using namespace detail::stream_state::exports;
+}

IOStreams/delimiters.h

@@ -10,6 +10,8 @@ static_assert( __cplusplus > 2020'00 );
 
 #include <Alepha/StaticValue.h>
 
+#include <Alepha/IOStreams/StreamState.h>
+
 namespace Alepha::Hydrogen::IOStreams  ::detail::  delimiters
 {
 	inline namespace exports
@@ -18,19 +20,21 @@ namespace Alepha::Hydrogen::IOStreams  ::detail::  delimiters
 		enum { RecordDelimiter };
 	}
 
+	using FieldDelimiterState= StreamState< decltype( FieldDelimiter ), std::string >;
+
 	namespace C
 	{
-		const char defaultFieldDelimiter= '\t';
+		const std::string defaultFieldDelimiter= "\t";
 		const char defaultRecordDelimiter= '\n';
 	}
 
 	namespace storage
 	{
-		inline StaticValue< std::optional< char > > globalFieldDelimiter;
+		inline StaticValue< std::optional< std::string > > globalFieldDelimiter;
 		inline StaticValue< std::optional< char > > globalRecordDelimiter;
 	}
 
-	inline char
+	inline std::string
 	globalFieldDelimiter()
 	{
 		if( not storage::globalFieldDelimiter().has_value() ) storage::globalFieldDelimiter()= C::defaultFieldDelimiter;
@@ -43,48 +47,19 @@ namespace Alepha::Hydrogen::IOStreams  ::detail::  delimiters
 		if( not storage::globalRecordDelimiter().has_value() ) storage::globalRecordDelimiter()= C::defaultRecordDelimiter;
 		return storage::globalRecordDelimiter().value();
 	}
-	
-
-	inline const int fieldIndex= std::ios::xalloc();
-
-	inline void
-	setFieldDelimiterOnIOS( std::ios &ios, const char ch )
-	{
-		ios.iword( fieldIndex )= ch;
-	}
-
-	inline char
-	getFieldDelimiter( std::ios &ios )
-	{
-		if( ios.iword( fieldIndex ) == 0 ) setFieldDelimiterOnIOS( ios, globalFieldDelimiter() );
-
-		return ios.iword( fieldIndex );
-	}
 
 	inline std::ostream &
 	operator << ( std::ostream &os, decltype( FieldDelimiter ) )
 	{
-		return os << getFieldDelimiter( os );
+		return os << FieldDelimiterState::get( os );
 	}
 
-	struct FieldDelimiterSetter
-	{
-		const char ch;
-
-		friend std::ostream &
-		operator << ( std::ostream &os, const FieldDelimiterSetter &s )
-		{
-			setFieldDelimiterOnIOS( os, s.ch );
-			return os;
-		}
-	};
-
 	namespace exports
 	{
 		auto
-		setFieldDelimiter( const char ch )
+		setFieldDelimiter( const std::string delim )
 		{
-			return FieldDelimiterSetter{ ch };
+			return FieldDelimiterState::Setter{ delim };
 		}
 	}