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r24755:9b2ef076754d 2.2 KiB text/x-c Show Annotation Show as Raw Download as Raw

Michael Lutz

Codechange: Don't use cpp_offsetof in the save/load code.

Many of the member variables that are used in save/load are inside types
that are not standard layout types. Using pointer arithmetics to determine
addresses of members inside types that are not standard layout is generally
undefined behaviour. If we'd use C++17, it is conditionally supported, which means
each compiler may or may not support it. And even then using it for individual
array elements is syntactically not supported the the standard offsetof function.

Unfortunately, the trickery employed for saving linkgraph settings causes quite some
clutter in the settings ini files.

/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file signal_func.h Functions related to signals. */

#ifndef SIGNAL_FUNC_H
#define SIGNAL_FUNC_H

#include "track_type.h"
#include "tile_type.h"
#include "direction_type.h"
#include "company_type.h"

/**
 * Maps a trackdir to the bit that stores its status in the map arrays, in the
 * direction along with the trackdir.
 */
static inline byte SignalAlongTrackdir(Trackdir trackdir)
{
	extern const byte _signal_along_trackdir[TRACKDIR_END];
	return _signal_along_trackdir[trackdir];
}

/**
 * Maps a trackdir to the bit that stores its status in the map arrays, in the
 * direction against the trackdir.
 */
static inline byte SignalAgainstTrackdir(Trackdir trackdir)
{
	extern const byte _signal_against_trackdir[TRACKDIR_END];
	return _signal_against_trackdir[trackdir];
}

/**
 * Maps a Track to the bits that store the status of the two signals that can
 * be present on the given track.
 */
static inline byte SignalOnTrack(Track track)
{
	extern const byte _signal_on_track[TRACK_END];
	return _signal_on_track[track];
}

/** State of the signal segment */
enum SigSegState {
	SIGSEG_FREE,    ///< Free and has no pre-signal exits or at least one green exit
	SIGSEG_FULL,    ///< Occupied by a train
	SIGSEG_PBS,     ///< Segment is a PBS segment
};

SigSegState UpdateSignalsOnSegment(TileIndex tile, DiagDirection side, Owner owner);
void SetSignalsOnBothDir(TileIndex tile, Track track, Owner owner);
void AddTrackToSignalBuffer(TileIndex tile, Track track, Owner owner);
void AddSideToSignalBuffer(TileIndex tile, DiagDirection side, Owner owner);
void UpdateSignalsInBuffer();

#endif /* SIGNAL_FUNC_H */