Fixes for pre c++20

file constructor from raw data

CMakeLists.txt

@@ -313,6 +313,12 @@ install(
 	COMPONENT Devel
 )
 
+install(
+	FILES include/cif++.hpp
+	DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+	COMPONENT Devel
+)
+
 install(FILES
 	${PROJECT_SOURCE_DIR}/rsrc/mmcif_ddl.dic
 	${PROJECT_SOURCE_DIR}/rsrc/mmcif_pdbx.dic

include/cif++/file.hpp

@@ -51,6 +51,20 @@ class file : public std::list<datablock>
 		load(is);
 	}
 
+	explicit file(const char *data, size_t length)
+	{
+		struct membuf : public std::streambuf
+		{
+			membuf(char *text, size_t length)
+			{
+				this->setg(text, text, text + length);
+			}
+		} buffer(const_cast<char *>(data), length);
+
+		std::istream is(&buffer);
+		load(is);
+	}
+
 	file(const file &) = default;
 	file(file &&) = default;
 	file &operator=(const file &) = default;

include/cif++/item.hpp

@@ -234,6 +234,15 @@ struct item_handle
 		return item_value_as<T>::compare(*this, value, true) == 0;
 	}
 
+	// We may not have C++20 yet...
+
+	template <typename T>
+	bool operator!=(const T &value) const
+	{
+		// TODO: icase or not icase?
+		return item_value_as<T>::compare(*this, value, true) != 0;
+	}
+
 	// empty means either null or unknown
 	bool empty() const
 	{