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/* $Id$ */

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#include "stdafx.h"

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#include "openttd.h"

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#include "rail.h"

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#include "station.h"

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/* XXX: Below 3 tables store duplicate data. Maybe remove some? */

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/* Maps a trackdir to the bit that stores its status in the map arrays, in the

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 * direction along with the trackdir */

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const byte _signal_along_trackdir[] = {

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	0x80, 0x80, 0x80, 0x20, 0x40, 0x10, 0, 0,

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	0x40, 0x40, 0x40, 0x10, 0x80, 0x20

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};

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/* Maps a trackdir to the bit that stores its status in the map arrays, in the

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 * direction against the trackdir */

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const byte _signal_against_trackdir[] = {

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	0x40, 0x40, 0x40, 0x10, 0x80, 0x20, 0, 0,

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	0x80, 0x80, 0x80, 0x20, 0x40, 0x10

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};

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/* Maps a Track to the bits that store the status of the two signals that can

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 * be present on the given track */

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const byte _signal_on_track[] = {

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	0xC0, 0xC0, 0xC0, 0x30, 0xC0, 0x30

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};

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/* Maps a diagonal direction to the all trackdirs that are connected to any

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 * track entering in this direction (including those making 90 degree turns)

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 */

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const TrackdirBits _exitdir_reaches_trackdirs[] = {

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	TRACKDIR_BIT_X_NE | TRACKDIR_BIT_LOWER_E | TRACKDIR_BIT_LEFT_N,  /* DIAGDIR_NE */

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	TRACKDIR_BIT_Y_SE | TRACKDIR_BIT_LEFT_S  | TRACKDIR_BIT_UPPER_E, /* DIAGDIR_SE */

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	TRACKDIR_BIT_X_SW | TRACKDIR_BIT_UPPER_W | TRACKDIR_BIT_RIGHT_S, /* DIAGDIR_SW */

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	TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_RIGHT_N | TRACKDIR_BIT_LOWER_W  /* DIAGDIR_NW */

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};

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const Trackdir _next_trackdir[] = {

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	TRACKDIR_X_NE,  TRACKDIR_Y_SE,  TRACKDIR_LOWER_E, TRACKDIR_UPPER_E, TRACKDIR_RIGHT_S, TRACKDIR_LEFT_S, INVALID_TRACKDIR, INVALID_TRACKDIR,

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	TRACKDIR_X_SW,  TRACKDIR_Y_NW,  TRACKDIR_LOWER_W, TRACKDIR_UPPER_W, TRACKDIR_RIGHT_N, TRACKDIR_LEFT_N

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};

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/* Maps a trackdir to all trackdirs that make 90 deg turns with it. */

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const TrackdirBits _track_crosses_trackdirs[] = {

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	TRACKDIR_BIT_Y_SE     | TRACKDIR_BIT_Y_NW,                                                   /* TRACK_X     */

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	TRACKDIR_BIT_X_NE     | TRACKDIR_BIT_X_SW,                                                   /* TRACK_Y     */

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	TRACKDIR_BIT_RIGHT_N  | TRACKDIR_BIT_RIGHT_S  | TRACKDIR_BIT_LEFT_N  | TRACKDIR_BIT_LEFT_S,  /* TRACK_UPPER */

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	TRACKDIR_BIT_RIGHT_N  | TRACKDIR_BIT_RIGHT_S  | TRACKDIR_BIT_LEFT_N  | TRACKDIR_BIT_LEFT_S,  /* TRACK_LOWER */

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	TRACKDIR_BIT_UPPER_W  | TRACKDIR_BIT_UPPER_E  | TRACKDIR_BIT_LOWER_W | TRACKDIR_BIT_LOWER_E, /* TRACK_LEFT  */

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	TRACKDIR_BIT_UPPER_W  | TRACKDIR_BIT_UPPER_E  | TRACKDIR_BIT_LOWER_W | TRACKDIR_BIT_LOWER_E  /* TRACK_RIGHT */

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};

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/* Maps a track to all tracks that make 90 deg turns with it. */

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const TrackBits _track_crosses_tracks[] = {

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	TRACK_BIT_Y,                       /* TRACK_X     */

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	TRACK_BIT_X,                       /* TRACK_Y     */

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	TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, /* TRACK_UPPER */

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	TRACK_BIT_LEFT  | TRACK_BIT_RIGHT, /* TRACK_LOWER */

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	TRACK_BIT_UPPER | TRACK_BIT_LOWER, /* TRACK_LEFT  */

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	TRACK_BIT_UPPER | TRACK_BIT_LOWER  /* TRACK_RIGHT */

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};

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/* Maps a trackdir to the (4-way) direction the tile is exited when following

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 * that trackdir */

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const DiagDirection _trackdir_to_exitdir[] = {

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	DIAGDIR_NE,DIAGDIR_SE,DIAGDIR_NE,DIAGDIR_SE,DIAGDIR_SW,DIAGDIR_SE, DIAGDIR_NE,DIAGDIR_NE,

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	DIAGDIR_SW,DIAGDIR_NW,DIAGDIR_NW,DIAGDIR_SW,DIAGDIR_NW,DIAGDIR_NE,

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};

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const Trackdir _track_exitdir_to_trackdir[][DIAGDIR_END] = {

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	{TRACKDIR_X_NE,     INVALID_TRACKDIR,  TRACKDIR_X_SW,     INVALID_TRACKDIR},

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	{INVALID_TRACKDIR,  TRACKDIR_Y_SE,     INVALID_TRACKDIR,  TRACKDIR_Y_NW},

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	{TRACKDIR_UPPER_E,  INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_UPPER_W},

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	{INVALID_TRACKDIR,  TRACKDIR_LOWER_E,  TRACKDIR_LOWER_W,  INVALID_TRACKDIR},

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	{INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_LEFT_S,   TRACKDIR_LEFT_N},

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	{TRACKDIR_RIGHT_N,  TRACKDIR_RIGHT_S,  INVALID_TRACKDIR,  INVALID_TRACKDIR}

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};

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const Trackdir _track_enterdir_to_trackdir[][DIAGDIR_END] = { // TODO: replace magic with enums

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	{TRACKDIR_X_NE,     INVALID_TRACKDIR,  TRACKDIR_X_SW,     INVALID_TRACKDIR},

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	{INVALID_TRACKDIR,  TRACKDIR_Y_SE,     INVALID_TRACKDIR,  TRACKDIR_Y_NW},

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	{INVALID_TRACKDIR,  TRACKDIR_UPPER_E,  TRACKDIR_UPPER_W,  INVALID_TRACKDIR},

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	{TRACKDIR_LOWER_E,  INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_LOWER_W},

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	{TRACKDIR_LEFT_N,   TRACKDIR_LEFT_S,   INVALID_TRACKDIR,  INVALID_TRACKDIR},

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	{INVALID_TRACKDIR,  INVALID_TRACKDIR,  TRACKDIR_RIGHT_S,  TRACKDIR_RIGHT_N}

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};

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const Trackdir _track_direction_to_trackdir[][DIR_END] = {

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	{INVALID_TRACKDIR, TRACKDIR_X_NE,     INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_X_SW,     INVALID_TRACKDIR, INVALID_TRACKDIR},

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	{INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_Y_SE,     INVALID_TRACKDIR, INVALID_TRACKDIR,  INVALID_TRACKDIR, TRACKDIR_Y_NW},

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	{INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_UPPER_E, INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_UPPER_W, INVALID_TRACKDIR},

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	{INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_LOWER_E, INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_LOWER_W, INVALID_TRACKDIR},

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	{TRACKDIR_LEFT_N,  INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_LEFT_S,  INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR},

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	{TRACKDIR_RIGHT_N, INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR,  TRACKDIR_RIGHT_S, INVALID_TRACKDIR,  INVALID_TRACKDIR, INVALID_TRACKDIR}

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};

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const Trackdir _dir_to_diag_trackdir[] = {

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	TRACKDIR_X_NE, TRACKDIR_Y_SE, TRACKDIR_X_SW, TRACKDIR_Y_NW,

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};

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const Trackdir _reverse_trackdir[] = {

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	TRACKDIR_X_SW, TRACKDIR_Y_NW, TRACKDIR_UPPER_W, TRACKDIR_LOWER_W, TRACKDIR_LEFT_N, TRACKDIR_RIGHT_N, INVALID_TRACKDIR, INVALID_TRACKDIR,

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	TRACKDIR_X_NE, TRACKDIR_Y_SE, TRACKDIR_UPPER_E, TRACKDIR_LOWER_E, TRACKDIR_LEFT_S, TRACKDIR_RIGHT_S

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};

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RailType GetTileRailType(TileIndex tile, Trackdir trackdir)

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{

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	RailType type = INVALID_RAILTYPE;

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	DiagDirection exitdir = TrackdirToExitdir(trackdir);

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	switch (GetTileType(tile)) {

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		case MP_RAILWAY:

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			/* railway track */

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			type = _m[tile].m3 & RAILTYPE_MASK;

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			break;

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		case MP_STREET:

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			/* rail/road crossing */

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			if (IsLevelCrossing(tile))

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				type = _m[tile].m4 & RAILTYPE_MASK;

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			break;

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		case MP_STATION:

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			if (IsTrainStationTile(tile))

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				type = _m[tile].m3 & RAILTYPE_MASK;

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			break;

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		case MP_TUNNELBRIDGE:

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			/* railway tunnel */

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			if ((_m[tile].m5 & 0xFC) == 0) type = _m[tile].m3 & RAILTYPE_MASK;

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			/* railway bridge ending */

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			if ((_m[tile].m5 & 0xC6) == 0x80) type = _m[tile].m3 & RAILTYPE_MASK;

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			/* on railway bridge */

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			if ((_m[tile].m5 & 0xC6) == 0xC0 && ((DiagDirection)(_m[tile].m5 & 0x1)) == (exitdir & 0x1))

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				type = (_m[tile].m3 >> 4) & RAILTYPE_MASK;

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			/* under bridge (any type) */

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			if ((_m[tile].m5 & 0xC0) == 0xC0 && (_m[tile].m5 & 0x1U) != (exitdir & 0x1))

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				type = _m[tile].m3 & RAILTYPE_MASK;

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			break;

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		default:

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			break;

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	}

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	return type;

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}