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rubidium

(svn r20593) -Fix: (rlongago, r20547): long ago the service interval was int16, after which is got converted to Date except in the order backup. Much later I copied the savegame snippets from a vehicle and applied that on the order backup. Presto, reading/writing 32 bits (of Date) into 16 bits of ancient style service interval. That would then "spoil" the name pointer and that eventually crashes OpenTTD as it's likely to be an invalid pointer.

/* $Id$ */

/*
 * 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 zoom_func.h Functions related to zooming. */

#ifndef ZOOM_FUNC_H
#define ZOOM_FUNC_H

#include "zoom_type.h"

/**
 * Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)
 * When shifting right, value is rounded up
 * @param value value to shift
 * @param zoom  zoom level to shift to
 * @return shifted value
 */
static inline int ScaleByZoom(int value, ZoomLevel zoom)
{
	if (zoom == ZOOM_LVL_NORMAL) return value;
	int izoom = zoom - ZOOM_LVL_NORMAL;
	return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : (value + (1 << -izoom) - 1) >> -izoom;
}

/**
 * Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)
 * When shifting right, value is rounded up
 * @param value value to shift
 * @param zoom  zoom level to shift to
 * @return shifted value
 */
static inline int UnScaleByZoom(int value, ZoomLevel zoom)
{
	if (zoom == ZOOM_LVL_NORMAL) return value;
	int izoom = zoom - ZOOM_LVL_NORMAL;
	return (zoom > ZOOM_LVL_NORMAL) ? (value + (1 << izoom) - 1) >> izoom : value << -izoom;
}

/**
 * Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)
 * @param value value to shift
 * @param zoom  zoom level to shift to
 * @return shifted value
 */
static inline int ScaleByZoomLower(int value, ZoomLevel zoom)
{
	if (zoom == ZOOM_LVL_NORMAL) return value;
	int izoom = zoom - ZOOM_LVL_NORMAL;
	return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : value >> -izoom;
}

/**
 * Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)
 * @param value value to shift
 * @param zoom  zoom level to shift to
 * @return shifted value
 */
static inline int UnScaleByZoomLower(int value, ZoomLevel zoom)
{
	if (zoom == ZOOM_LVL_NORMAL) return value;
	int izoom = zoom - ZOOM_LVL_NORMAL;
	return (zoom > ZOOM_LVL_NORMAL) ? value >> izoom : value << -izoom;
}

#endif /* ZOOM_FUNC_H */