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/* $Id$ */

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/** @file pathfind.h The oldest pathfinder that's supported. */

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#ifndef PATHFIND_H

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#define PATHFIND_H

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#include "direction_type.h"

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enum {

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	STR_FACTOR  = 2,

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	DIAG_FACTOR = 3

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};

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//#define PF_BENCH // perform simple benchmarks on the train pathfinder (not

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//supported on all archs)

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struct TrackPathFinder;

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typedef bool TPFEnumProc(TileIndex tile, void *data, Trackdir trackdir, uint length);

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typedef void TPFAfterProc(TrackPathFinder *tpf);

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typedef bool NTPEnumProc(TileIndex tile, void *data, int track, uint length);

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#define PATHFIND_GET_LINK_OFFS(tpf, link) ((byte*)(link) - (byte*)tpf->links)

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#define PATHFIND_GET_LINK_PTR(tpf, link_offs) (TrackPathFinderLink*)((byte*)tpf->links + (link_offs))

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/* y7 y6 y5 y4 y3 y2 y1 y0 x7 x6 x5 x4 x3 x2 x1 x0

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 * y7 y6 y5 y4 y3 y2 y1 y0 x4 x3 x2 x1 x0  0  0  0

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 *  0  0 y7 y6 y5 y4 y3 y2 y1 y0 x4 x3 x2 x1 x0  0

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 *  0  0  0  0 y5 y4 y3 y2 y1 y0 x4 x3 x2 x1 x0  0

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 */

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#define PATHFIND_HASH_TILE(tile) (TileX(tile) & 0x1F) + ((TileY(tile) & 0x1F) << 5)

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struct TrackPathFinderLink {

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	TileIndex tile;

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	uint16 flags;

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	uint16 next;

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};

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struct RememberData {

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	uint16 cur_length;

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	byte depth;

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	Track last_choosen_track;

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};

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struct TrackPathFinder {

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	int num_links_left;

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	TrackPathFinderLink *new_link;

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	TPFEnumProc *enum_proc;

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	void *userdata;

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	RememberData rd;

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	TrackdirByte the_dir;

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	TransportType tracktype;

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	uint sub_type;

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	bool disable_tile_hash;

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	uint16 hash_head[0x400];

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	TileIndex hash_tile[0x400];       ///< stores the link index when multi link.

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	TrackPathFinderLink links[0x400]; ///< hopefully, this is enough.

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};

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/** Some flags to modify the behaviour of original pathfinder */

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enum PathfindFlags {

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	PATHFIND_FLAGS_NONE              = 0,

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	PATHFIND_FLAGS_SHIP_MODE         = 0x0800, ///< pathfinder with some optimizations for ships, but does not work for other types.

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	PATHFIND_FLAGS_DISABLE_TILE_HASH = 0x1000, ///< do not check for searching in circles

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};

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DECLARE_ENUM_AS_BIT_SET(PathfindFlags)

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void FollowTrack(TileIndex tile, PathfindFlags flags, TransportType tt, uint sub_type, DiagDirection direction, TPFEnumProc* enum_proc, TPFAfterProc* after_proc, void* data);

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void NewTrainPathfind(TileIndex tile, TileIndex dest, RailTypes railtypes, DiagDirection direction, NTPEnumProc* enum_proc, void* data);

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#endif /* PATHFIND_H */