Refactoring in map reading code - part 2/2

include/implem/mapstreamraw.inl

@@ -0,0 +1,74 @@
+namespace dk {
+	namespace implem {
+		///---------------------------------------------------------------------
+		///Only enabled if Device::MapDimensions is defined and is the same
+		///as D. The function's name is set to give a hint to the user as to
+		///why the error has occurred (they are trying to construct a
+		///TileMapData with a set dimension that is different from the one
+		///hardcoded in the device being passed in). The actual name could be
+		///something like get_device_dimensions().
+		///---------------------------------------------------------------------
+		template <std::size_t D, typename Device>
+		inline
+		typename std::enable_if<Device::MapDimensions == D, std::size_t>::type err_mismatching_dimension (const Device*) noexcept {
+				return Device::MapDimensions;
+		}
+
+		///---------------------------------------------------------------------
+		///Only enabled if Device::MapDimensions is not defined. The function's
+		///name is set to give a hint to the user as to why the error has
+		///occurred (they are trying to construct a TileMapData with a set
+		///dimension that is different from the one hardcoded in the device
+		///being passed in). The actual name could be something like
+		///get_device_dimensions().
+		///---------------------------------------------------------------------
+		template <std::size_t D, typename Device>
+		inline
+		typename std::enable_if<HasMapDimensions<Device>::result == false, std::size_t>::type err_mismatching_dimension (const Device*) noexcept {
+			return 0;
+		}
+
+		///---------------------------------------------------------------------
+		///---------------------------------------------------------------------
+		template <std::size_t D, typename Device>
+		inline
+		typename std::enable_if<Device::MapDimensions == D, Vector<CoordinateScalarType, D>>::type retrieve_map_size_from_device (Device* parDevice) {
+			return parDevice->mapSize();
+		}
+
+		///---------------------------------------------------------------------
+		///---------------------------------------------------------------------
+		template <std::size_t D, typename Device>
+		inline
+		typename std::enable_if<HasMapDimensions<Device>::result == false, Vector<CoordinateScalarType, D>>::type retrieve_map_size_from_device (Device* parDevice) {
+			return get_map_size_from_device<D>(parDevice);
+		}
+	} //namespace implem
+
+	///-------------------------------------------------------------------------
+	///-------------------------------------------------------------------------
+	template <typename T, std::size_t D>
+	template <typename Device>
+	MapStreamRaw<T, D>::MapStreamRaw (Device& parDevice) :
+		MapStreamBase<D>(implem::retrieve_map_size_from_device<D>(&parDevice)),
+		m_istream(&parDevice),
+		m_deviceHasDim(D == implem::err_mismatching_dimension<D>(&parDevice))
+	{
+	}
+
+	///-------------------------------------------------------------------------
+	///-------------------------------------------------------------------------
+	template <typename T, std::size_t D>
+	std::size_t MapStreamRaw<T, D>::dataBlockRequested (char* parOut, std::size_t parOutSize, const coords& parFrom, const coords& parTo) {
+		DK_ASSERT(parOut);
+
+		const std::size_t totalBlocks = implem::area(parTo - parFrom);
+		const std::size_t storableBlocks = parOutSize / sizeof(T);
+		const std::size_t readMem = sizeof(T) * std::min(storableBlocks, totalBlocks);
+
+		const std::streamoff readPos = static_cast<std::streamoff>(implem::area(parFrom));
+		m_istream.seekg(readPos, std::ios_base::beg);
+		m_istream.read(parOut, readMem);
+		return readMem;
+	}
+} //namespace dk

include/mapreaders/mapstreamraw.hpp

@@ -0,0 +1,65 @@
+#ifndef id56E2396E102B4E10B20466D6B57A4C66
+#define id56E2396E102B4E10B20466D6B57A4C66
+
+#include "mapreaders/mapstreambase.hpp"
+#include "implem/helpers.hpp"
+#include <cstddef>
+#include <algorithm>
+#include <type_traits>
+#include <istream>
+
+namespace dk {
+	namespace implem {
+		template <typename T>
+		class HasMapDimensions {
+			class yes { char m; };
+			class nope { yes m[2]; };
+			static yes deduce ( int a, int b = T::MapDimensions );
+			static nope deduce ( ... );
+		public:
+			enum {
+				result = (sizeof(yes) == sizeof(deduce(1)))
+			};
+		};
+
+		template <std::size_t D, typename Device>
+		typename std::enable_if<Device::MapDimensions == D, std::size_t>::type err_mismatching_dimension ( const Device* ) noexcept a_pure;
+
+		template <std::size_t D, typename Device>
+		typename std::enable_if<HasMapDimensions<Device>::result == false, std::size_t>::type err_mismatching_dimension ( const Device* ) noexcept a_pure;
+
+		template <std::size_t D, typename Device>
+		typename std::enable_if<Device::MapDimensions == D, Vector<CoordinateScalarType, D>>::type retrieve_map_size_from_device ( Device* parDevice );
+
+		template <std::size_t D, typename Device>
+		typename std::enable_if<HasMapDimensions<Device>::result == false, Vector<CoordinateScalarType, D>>::type retrieve_map_size_from_device ( Device* parDevice );
+	} //namespace implem
+
+	//Customization point - specialize to enable map size retrieval for Device
+	template <std::size_t D, typename Device>
+	typename Device::coords get_map_size_from_device ( const Device* parDevice );
+
+	template <typename T, std::size_t D>
+	class MapStreamRaw : public MapStreamBase<D> {
+	public:
+		typedef typename MapStreamBase<D>::coords coords;
+
+		MapStreamRaw ( void ) = delete;
+		template <typename Device>
+		explicit MapStreamRaw ( Device& parDevice );
+		virtual ~MapStreamRaw ( void ) noexcept = default;
+
+		virtual bool isReadable ( void ) const { return true; }
+		virtual bool isWriteable ( void ) const { return false; }
+
+	private:
+		virtual std::size_t dataBlockRequested ( char* parOut, std::size_t parOutSize, const coords& parFrom, const coords& parTo );
+
+		std::istream m_istream;
+		const bool m_deviceHasDim;
+	};
+} //namespace dk
+
+#include "implem/mapstreamraw.inl"
+
+#endif