Port to CMake from qmake, and split decoder into subdirectory

Qt 5 has had to be dropped as CMakeLists.txt uses qt_* specific commands
which are implemented in Qt 6 onwards.

cmake --install is only working on Linux at the moment; it installs the
executable and the bundled example tti files into /usr/local/share/doc

The teletext decoder with its document storage has been moved to a
subdirectory with the intention of making it possible to use in other
projects, but some further separation of editing stuff will be needed.

src/qteletextdecoder/x26triplets.h

@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2020-2024 Gavin MacGregor
+ *
+ * This file is part of QTeletextMaker.
+ *
+ * QTeletextMaker 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.
+ *
+ * QTeletextMaker 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 QTeletextMaker.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef X26TRIPLETS_H
+#define X26TRIPLETS_H
+
+#include <QList>
+
+class X26Triplet
+{
+public:
+	// x26model.h has the Plain English descriptions of these errors
+	enum X26TripletError { NoError, ActivePositionMovedUp, ActivePositionMovedLeft, InvokePointerInvalid, InvokeTypeMismatch, OriginModifierAlone };
+	enum ObjectSource { InvalidObjectSource, LocalObject, POPObject, GPOPObject };
+
+	X26Triplet() {}
+//	X26Triplet(const X26Triplet &other);
+
+//	X26Triplet &operator=(const X26Triplet &other);
+
+	X26Triplet(int address, int mode, int data);
+
+	int address() const { return m_address; }
+	int mode() const { return m_mode; }
+	int modeExt() const { return (m_address >= 40) ? m_mode : (m_mode | 0x20); }
+	int data() const { return m_data; }
+	int addressRow() const { return (m_address == 40) ? 24 :m_address-40; }
+	int addressColumn() const { return (m_address); }
+	bool isRowTriplet() const { return (m_address >= 40); }
+
+	void setAddress(int address);
+	void setMode(int mode);
+	void setData(int data);
+	void setAddressRow(int addressRow);
+	void setAddressColumn(int addressColumn);
+
+	int objectSource() const { return (m_address & 0x18) >> 3; }
+
+	int objectLocalDesignationCode() const { return (((m_address & 0x01) << 3) | (m_data >> 4)); }
+	int objectLocalTripletNumber() const { return m_data & 0x0f; }
+	int objectLocalIndex() const { return objectLocalDesignationCode() * 13 + objectLocalTripletNumber(); }
+	void setObjectLocalDesignationCode(int i);
+	void setObjectLocalTripletNumber(int i);
+	void setObjectLocalIndex(int i);
+
+	int activePositionRow() const { return m_activePositionRow; }
+	int activePositionColumn() const { return m_activePositionColumn; }
+	int activePositionRow1p5() const { return m_activePositionRow1p5; }
+	int activePositionColumn1p5() const { return m_activePositionColumn1p5; }
+	X26TripletError error() const { return m_error; }
+	bool reservedMode() const { return m_reservedMode; }
+	bool reservedData() const { return m_reservedData; }
+
+	friend class X26TripletList;
+
+private:
+	// Only these variables are manipulated by the X26Triplet class
+	int m_address, m_mode, m_data;
+	// and the following are filled in by X26TripletList::updateInternalData()
+	int m_activePositionRow = -1;
+	int m_activePositionColumn = -1;
+	int m_activePositionRow1p5 = -1;
+	int m_activePositionColumn1p5 = -1;
+	X26TripletError m_error = NoError;
+	bool m_reservedMode = false;
+	bool m_reservedData = false;
+};
+
+class X26TripletList
+{
+public:
+	void append(const X26Triplet &value);
+	void insert(int i, const X26Triplet &value);
+	void removeAt(int i);
+	void replace(int i, const X26Triplet &value);
+
+	void removeLast() { m_list.removeLast(); }
+
+	const X26Triplet &at(int i) const { return m_list.at(i); }
+	bool isEmpty() const { return m_list.isEmpty(); }
+	void reserve(int alloc) { m_list.reserve(alloc); }
+	int size() const { return m_list.size(); }
+	const QList<int> &objects(int t) const { return m_objects[t]; };
+
+private:
+	void updateInternalData();
+
+	QList<X26Triplet> m_list;
+	QList<int> m_objects[3];
+
+	class ActivePosition
+	{
+	public:
+		ActivePosition();
+		void reset();
+//		int row() const { return (m_row == -1) ? 0 : m_row; }
+//		int column() const { return (m_column == -1) ? 0 : m_column; }
+		int row() const { return m_row; }
+		int column() const { return m_column; }
+		bool isDeployed() const { return m_row != -1; }
+		bool setRow(int);
+		bool setColumn(int);
+//		bool setRowAndColumn(int, int);
+
+	private:
+		int m_row, m_column;
+	};
+};
+
+#endif