[libcalamares] Named enumeration support

src/libcalamares/utils/NamedEnum.h

@@ -0,0 +1,88 @@
+/* === This file is part of Calamares - <https://github.com/calamares> ===
+ *
+ *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @brief Support for "named" enumerations
+ *
+ * For tables which map string names to enum values, provide a NamedEnumTable
+ * which hangs on to an initializer_list of pairs of names and values.
+ * This table can be used with find() to map names to values, or
+ * values to names. A convenience function smash() is provided to help
+ * in printing integer (underlying) values of an enum.
+ */
+
+#ifndef LIBCALAMARES_NAMEDENUM_H
+#define LIBCALAMARES_NAMEDENUM_H
+
+#include <QString>
+
+#include <type_traits>
+#include <initializer_list>
+
+/** @brief Type for collecting parts of a named enum. */
+template<typename T>
+struct NamedEnumTable
+{
+    using string_t = QString;
+    using enum_t = T;
+    using pair_t = std::pair< string_t, enum_t >;
+    using type = std::initializer_list< pair_t >;
+} ;
+
+/** @brief Find a name @p s in the @p table. */
+template<typename T>
+typename NamedEnumTable<T>::enum_t find( const typename NamedEnumTable<T>::type& table, const QString& s, bool& ok )
+{
+    ok = false;
+
+    for ( const auto p : table )
+        if ( s == p.first )
+        {
+            ok = true;
+            return p.second;
+        }
+
+    // ok is still false
+    return table.begin()->second;
+}
+
+/** @brief Find a value @p s in the @p table. */
+template<typename T>
+typename NamedEnumTable<T>::enum_t find( const typename NamedEnumTable<T>::type& table, const T s, bool& ok )
+{
+    ok = false;
+
+    for ( const auto p : table )
+        if ( s == p.second)
+        {
+            ok = true;
+            return p.first;
+        }
+
+    // ok is still false
+    return QString();
+}
+
+/** @brief Smashes an enum value to its underlying type. */
+template<typename E>
+constexpr typename std::underlying_type<E>::type smash( const E e )
+{
+    return static_cast<typename std::underlying_type<E>::type>( e );
+}
+
+
+#endif