1

/* $Id$ */

     2

     3

#include "stdafx.h"

     4

#include "openttd.h"

     5

#include "bridge_map.h"

     6

#include "station_map.h"

     7

#include "depot.h"

     8

#include "functions.h"

     9

#include "map.h"

    10

#include "tile.h"

    11

#include "pathfind.h"

    12

#include "rail.h"

    13

#include "debug.h"

    14

#include "tunnel_map.h"

    15

#include "variables.h"

    16

#include "depot.h"

    17

    18

// remember which tiles we have already visited so we don't visit them again.

    19

static bool TPFSetTileBit(TrackPathFinder *tpf, TileIndex tile, int dir)

    20

{

    21

	uint hash, val, offs;

    22

	TrackPathFinderLink *link, *new_link;

    23

	uint bits = 1 << dir;

    24

    25

	if (tpf->disable_tile_hash)

    26

		return true;

    27

    28

	hash = PATHFIND_HASH_TILE(tile);

    29

    30

	val = tpf->hash_head[hash];

    31

    32

	if (val == 0) {

    33

		/* unused hash entry, set the appropriate bit in it and return true

    34

		 * to indicate that a bit was set. */

    35

		tpf->hash_head[hash] = bits;

    36

		tpf->hash_tile[hash] = tile;

    37

		return true;

    38

	} else if (!(val & 0x8000)) {

    39

		/* single tile */

    40

    41

		if (tile == tpf->hash_tile[hash]) {

    42

			/* found another bit for the same tile,

    43

			 * check if this bit is already set, if so, return false */

    44

			if (val & bits)

    45

				return false;

    46

    47

			/* otherwise set the bit and return true to indicate that the bit

    48

			 * was set */

    49

			tpf->hash_head[hash] = val | bits;

    50

			return true;

    51

		} else {

    52

			/* two tiles with the same hash, need to make a link */

    53

    54

			/* allocate a link. if out of links, handle this by returning

    55

			 * that a tile was already visisted. */

    56

			if (tpf->num_links_left == 0) {

    57

				return false;

    58

			}

    59

			tpf->num_links_left--;

    60

			link = tpf->new_link++;

    61

    62

			/* move the data that was previously in the hash_??? variables

    63

			 * to the link struct, and let the hash variables point to the link */

    64

			link->tile = tpf->hash_tile[hash];

    65

			tpf->hash_tile[hash] = PATHFIND_GET_LINK_OFFS(tpf, link);

    66

    67

			link->flags = tpf->hash_head[hash];

    68

			tpf->hash_head[hash] = 0xFFFF; /* multi link */

    69

    70

			link->next = 0xFFFF;

    71

		}

    72

	} else {

    73

		/* a linked list of many tiles,

    74

		 * find the one corresponding to the tile, if it exists.

    75

		 * otherwise make a new link */

    76

    77

		offs = tpf->hash_tile[hash];

    78

		do {

    79

			link = PATHFIND_GET_LINK_PTR(tpf, offs);

    80

			if (tile == link->tile) {

    81

				/* found the tile in the link list,

    82

				 * check if the bit was alrady set, if so return false to indicate that the

    83

				 * bit was already set */

    84

				if (link->flags & bits)

    85

					return false;

    86

				link->flags |= bits;

    87

				return true;

    88

			}

    89

		} while ((offs=link->next) != 0xFFFF);

    90

	}

    91

    92

	/* get here if we need to add a new link to link,

    93

	 * first, allocate a new link, in the same way as before */

    94

	if (tpf->num_links_left == 0) {

    95

			return false;

    96

	}

    97

	tpf->num_links_left--;

    98

	new_link = tpf->new_link++;

    99

   100

	/* then fill the link with the new info, and establish a ptr from the old

   101

	 * link to the new one */

   102

	new_link->tile = tile;

   103

	new_link->flags = bits;

   104

	new_link->next = 0xFFFF;

   105

   106

	link->next = PATHFIND_GET_LINK_OFFS(tpf, new_link);

   107

	return true;

   108

}

   109

   110

static const byte _bits_mask[4] = {

   111

	0x19,

   112

	0x16,

   113

	0x25,

   114

	0x2A,

   115

};

   116

   117

static const byte _tpf_new_direction[14] = {

   118

	0, 1, 0, 1, 2, 1,

   119

	0, 0,

   120

	2, 3, 3, 2, 3, 0,

   121

};

   122

   123

static const byte _tpf_prev_direction[14] = {

   124

	0, 1, 1, 0, 1, 2,

   125

	0, 0,

   126

	2, 3, 2, 3, 0, 3,

   127

};

   128

   129

   130

static const byte _otherdir_mask[4] = {

   131

	0x10,

   132

	0,

   133

	0x5,

   134

	0x2A,

   135

};

   136

   137

static void TPFMode2(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)

   138

{

   139

	uint bits;

   140

	int i;

   141

	RememberData rd;

   142

   143

	assert(tpf->tracktype == TRANSPORT_WATER);

   144

   145

	// This addition will sometimes overflow by a single tile.

   146

	// The use of TILE_MASK here makes sure that we still point at a valid

   147

	// tile, and then this tile will be in the sentinel row/col, so GetTileTrackStatus will fail.

   148

	tile = TILE_MASK(tile + TileOffsByDiagDir(direction));

   149

   150

	if (++tpf->rd.cur_length > 50)

   151

		return;

   152

   153

	bits = GetTileTrackStatus(tile, tpf->tracktype);

   154

	bits = (byte)((bits | (bits >> 8)) & _bits_mask[direction]);

   155

	if (bits == 0)

   156

		return;

   157

   158

	assert(TileX(tile) != MapMaxX() && TileY(tile) != MapMaxY());

   159

   160

	if ( (bits & (bits - 1)) == 0 ) {

   161

		/* only one direction */

   162

		i = 0;

   163

		while (!(bits&1))

   164

			i++, bits>>=1;

   165

   166

		rd = tpf->rd;

   167

		goto continue_here;

   168

	}

   169

	/* several directions */

   170

	i=0;

   171

	do {

   172

		if (!(bits & 1)) continue;

   173

		rd = tpf->rd;

   174

   175

		// Change direction 4 times only

   176

		if ((byte)i != tpf->rd.pft_var6) {

   177

			if (++tpf->rd.depth > 4) {

   178

				tpf->rd = rd;

   179

				return;

   180

			}

   181

			tpf->rd.pft_var6 = (byte)i;

   182

		}

   183

   184

continue_here:;

   185

		tpf->the_dir = i + (HASBIT(_otherdir_mask[direction], i) ? 8 : 0);

   186

   187

		if (!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, NULL)) {

   188

			TPFMode2(tpf, tile, _tpf_new_direction[tpf->the_dir]);

   189

		}

   190

   191

		tpf->rd = rd;

   192

	} while (++i, bits>>=1);

   193

   194

}

   195

   196

   197

/* Returns the end tile and the length of a tunnel. The length does not

   198

 * include the starting tile (entry), it does include the end tile (exit).

   199

 */

   200

FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, DiagDirection dir)

   201

{

   202

	TileIndexDiff delta = TileOffsByDiagDir(dir);

   203

	uint z = GetTileZ(tile);

   204

	FindLengthOfTunnelResult flotr;

   205

   206

	flotr.length = 0;

   207

   208

	dir = ReverseDiagDir(dir);

   209

	do {

   210

		flotr.length++;

   211

		tile += delta;

   212

	} while(

   213

		!IsTunnelTile(tile) ||

   214

		GetTunnelDirection(tile) != dir ||

   215

		GetTileZ(tile) != z

   216

	);

   217

   218

	flotr.tile = tile;

   219

	return flotr;

   220

}

   221

   222

static const uint16 _tpfmode1_and[4] = { 0x1009, 0x16, 0x520, 0x2A00 };

   223

   224

static uint SkipToEndOfTunnel(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)

   225

{

   226

	FindLengthOfTunnelResult flotr;

   227

	TPFSetTileBit(tpf, tile, 14);

   228

	flotr = FindLengthOfTunnel(tile, direction);

   229

	tpf->rd.cur_length += flotr.length;

   230

	TPFSetTileBit(tpf, flotr.tile, 14);

   231

	return flotr.tile;

   232

}

   233

   234

const byte _ffb_64[128] = {

   235

 0,  0,  1,  0,  2,  0,  1,  0,

   236

 3,  0,  1,  0,  2,  0,  1,  0,

   237

 4,  0,  1,  0,  2,  0,  1,  0,

   238

 3,  0,  1,  0,  2,  0,  1,  0,

   239

 5,  0,  1,  0,  2,  0,  1,  0,

   240

 3,  0,  1,  0,  2,  0,  1,  0,

   241

 4,  0,  1,  0,  2,  0,  1,  0,

   242

 3,  0,  1,  0,  2,  0,  1,  0,

   243

   244

 0,  0,  0,  2,  0,  4,  4,  6,

   245

 0,  8,  8, 10,  8, 12, 12, 14,

   246

 0, 16, 16, 18, 16, 20, 20, 22,

   247

16, 24, 24, 26, 24, 28, 28, 30,

   248

 0, 32, 32, 34, 32, 36, 36, 38,

   249

32, 40, 40, 42, 40, 44, 44, 46,

   250

32, 48, 48, 50, 48, 52, 52, 54,

   251

48, 56, 56, 58, 56, 60, 60, 62,

   252

};

   253

   254

static void TPFMode1(TrackPathFinder* tpf, TileIndex tile, DiagDirection direction)

   255

{

   256

	uint bits;

   257

	int i;

   258

	RememberData rd;

   259

	TileIndex tile_org = tile;

   260

   261

	// check if the old tile can be left at that direction

   262

	if (tpf->tracktype == TRANSPORT_ROAD) {

   263

		// road stops and depots now have a track (r4419)

   264

		// don't enter road stop from the back

   265

		if (IsRoadStopTile(tile) && GetRoadStopDir(tile) != direction) return;

   266

		// don't enter road depot from the back

   267

		if (IsTileDepotType(tile, TRANSPORT_ROAD) && GetRoadDepotDirection(tile) != direction) return;

   268

	}

   269

   270

	if (IsTunnelTile(tile)) {

   271

		if (GetTunnelDirection(tile) != direction ||

   272

				GetTunnelTransportType(tile) != tpf->tracktype) {

   273

			return;

   274

		}

   275

		tile = SkipToEndOfTunnel(tpf, tile, direction);

   276

	}

   277

	tile += TileOffsByDiagDir(direction);

   278

   279

	/* Check in case of rail if the owner is the same */

   280

	if (tpf->tracktype == TRANSPORT_RAIL) {

   281

		// don't enter train depot from the back

   282

		if (IsTileDepotType(tile, TRANSPORT_RAIL) && GetRailDepotDirection(tile) == direction) return;

   283

   284

		if (IsTileType(tile_org, MP_RAILWAY) || IsTileType(tile_org, MP_STATION) || IsTileType(tile_org, MP_TUNNELBRIDGE))

   285

			if (IsTileType(tile, MP_RAILWAY) || IsTileType(tile, MP_STATION) || IsTileType(tile, MP_TUNNELBRIDGE))

   286

				/* Check if we are on a bridge (middle parts don't have an owner */

   287

				if (!IsBridgeTile(tile) || !IsBridgeMiddle(tile))

   288

					if (!IsBridgeTile(tile_org) || !IsBridgeMiddle(tile_org))

   289

						if (GetTileOwner(tile_org) != GetTileOwner(tile))

   290

							return;

   291

	}

   292

   293

	// check if the new tile can be entered from that direction

   294

	if (tpf->tracktype == TRANSPORT_ROAD) {

   295

		// road stops and depots now have a track (r4419)

   296

		// don't enter road stop from the back

   297

		if (IsRoadStopTile(tile) && ReverseDiagDir(GetRoadStopDir(tile)) != direction) return;

   298

		// don't enter road depot from the back

   299

		if (IsTileDepotType(tile, TRANSPORT_ROAD) && ReverseDiagDir(GetRoadDepotDirection(tile)) != direction) return;

   300

	}

   301

   302

	tpf->rd.cur_length++;

   303

   304

	bits = GetTileTrackStatus(tile, tpf->tracktype);

   305

   306

	if ((byte)bits != tpf->var2) {

   307

		bits &= _tpfmode1_and[direction];

   308

		bits = bits | (bits>>8);

   309

	}

   310

	bits &= 0xBF;

   311

   312

	if (bits != 0) {

   313

		if (!tpf->disable_tile_hash || (tpf->rd.cur_length <= 64 && (KILL_FIRST_BIT(bits) == 0 || ++tpf->rd.depth <= 7))) {

   314

			do {

   315

				i = FIND_FIRST_BIT(bits);

   316

				bits = KILL_FIRST_BIT(bits);

   317

   318

				tpf->the_dir = (_otherdir_mask[direction] & (byte)(1 << i)) ? (i+8) : i;

   319

				rd = tpf->rd;

   320

   321

				if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&

   322

						!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {

   323

					TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);

   324

				}

   325

				tpf->rd = rd;

   326

			} while (bits != 0);

   327

		}

   328

	}

   329

   330

	/* the next is only used when signals are checked.

   331

	 * seems to go in 2 directions simultaneously */

   332

   333

	/* if i can get rid of this, tail end recursion can be used to minimize

   334

	 * stack space dramatically. */

   335

   336

	/* If we are doing signal setting, we must reverse at evere tile, so we

   337

	 * iterate all the tracks in a signal block, even when a normal train would

   338

	 * not reach it (for example, when two lines merge */

   339

	if (tpf->hasbit_13)

   340

		return;

   341

   342

	tile = tile_org;

   343

	direction = ReverseDiagDir(direction);

   344

   345

	bits = GetTileTrackStatus(tile, tpf->tracktype);

   346

	bits |= (bits >> 8);

   347

   348

	if ( (byte)bits != tpf->var2) {

   349

		bits &= _bits_mask[direction];

   350

	}

   351

   352

	bits &= 0xBF;

   353

	if (bits == 0)

   354

		return;

   355

   356

	do {

   357

		i = FIND_FIRST_BIT(bits);

   358

		bits = KILL_FIRST_BIT(bits);

   359

   360

		tpf->the_dir = (_otherdir_mask[direction] & (byte)(1 << i)) ? (i+8) : i;

   361

		rd = tpf->rd;

   362

		if (TPFSetTileBit(tpf, tile, tpf->the_dir) &&

   363

				!tpf->enum_proc(tile, tpf->userdata, tpf->the_dir, tpf->rd.cur_length, &tpf->rd.pft_var6) ) {

   364

			TPFMode1(tpf, tile, _tpf_new_direction[tpf->the_dir]);

   365

		}

   366

		tpf->rd = rd;

   367

	} while (bits != 0);

   368

}

   369

   370

void FollowTrack(TileIndex tile, uint16 flags, DiagDirection direction, TPFEnumProc *enum_proc, TPFAfterProc *after_proc, void *data)

   371

{

   372

	TrackPathFinder tpf;

   373

   374

	assert(direction < 4);

   375

   376

	/* initialize path finder variables */

   377

	tpf.userdata = data;

   378

	tpf.enum_proc = enum_proc;

   379

	tpf.new_link = tpf.links;

   380

	tpf.num_links_left = lengthof(tpf.links);

   381

   382

	tpf.rd.cur_length = 0;

   383

	tpf.rd.depth = 0;

   384

	tpf.rd.pft_var6 = 0;

   385

   386

	tpf.var2 = HASBIT(flags, 15) ? 0x43 : 0xFF; /* 0x8000 */

   387

   388

	tpf.disable_tile_hash = HASBIT(flags, 12);  /* 0x1000 */

   389

	tpf.hasbit_13         = HASBIT(flags, 13);  /* 0x2000 */

   390

   391

   392

	tpf.tracktype = (byte)flags;

   393

   394

	if (HASBIT(flags, 11)) {

   395

		tpf.rd.pft_var6 = 0xFF;

   396

		tpf.enum_proc(tile, data, 0, 0, 0);

   397

		TPFMode2(&tpf, tile, direction);

   398

	} else {

   399

		/* clear the hash_heads */

   400

		memset(tpf.hash_head, 0, sizeof(tpf.hash_head));

   401

		TPFMode1(&tpf, tile, direction);

   402

	}

   403

   404

	if (after_proc != NULL)

   405

		after_proc(&tpf);

   406

}

   407

   408

typedef struct {

   409

	TileIndex tile;

   410

	uint16 cur_length; // This is the current length to this tile.

   411

	uint16 priority; // This is the current length + estimated length to the goal.

   412

	byte track;

   413

	byte depth;

   414

	byte state;

   415

	byte first_track;

   416

} StackedItem;

   417

   418

static const byte _new_track[6][4] = {

   419

{0,    0xff, 8,    0xff,},

   420

{0xff, 1,    0xff, 9,},

   421

{0xff, 2,    10,   0xff,},

   422

{3,    0xff, 0xff, 11,},

   423

{12,   4,    0xff, 0xff,},

   424

{0xff, 0xff, 5,    13,},

   425

};

   426

   427

typedef struct HashLink {

   428

	TileIndex tile;

   429

	uint16 typelength;

   430

	uint16 next;

   431

} HashLink;

   432

   433

typedef struct {

   434

	NTPEnumProc *enum_proc;

   435

	void *userdata;

   436

	TileIndex dest;

   437

   438

	TransportType tracktype;

   439

	RailTypeMask railtypes;

   440

	uint maxlength;

   441

   442

	HashLink *new_link;

   443

	uint num_links_left;

   444

   445

	uint nstack;

   446

	StackedItem stack[256]; // priority queue of stacked items

   447

   448

	uint16 hash_head[0x400]; // hash heads. 0 means unused. 0xFFFC = length, 0x3 = dir

   449

	TileIndex hash_tile[0x400]; // tiles. or links.

   450

   451

	HashLink links[0x400]; // hash links

   452

   453

} NewTrackPathFinder;

   454

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

   455

#define NTP_GET_LINK_PTR(tpf, link_offs) (HashLink*)((byte*)tpf->links + (link_offs))

   456

   457

#define ARR(i) tpf->stack[(i)-1]

   458

   459

// called after a new element was added in the queue at the last index.

   460

// move it down to the proper position

   461

static inline void HeapifyUp(NewTrackPathFinder *tpf)

   462

{

   463

	StackedItem si;

   464

	int i = ++tpf->nstack;

   465

   466

	while (i != 1 && ARR(i).priority < ARR(i>>1).priority) {

   467

		// the child element is larger than the parent item.

   468

		// swap the child item and the parent item.

   469

		si = ARR(i); ARR(i) = ARR(i>>1); ARR(i>>1) = si;

   470

		i>>=1;

   471

	}

   472

}

   473

   474

// called after the element 0 was eaten. fill it with a new element

   475

static inline void HeapifyDown(NewTrackPathFinder *tpf)

   476

{

   477

	StackedItem si;

   478

	int i = 1, j;

   479

	int n;

   480

   481

	assert(tpf->nstack > 0);

   482

	n = --tpf->nstack;

   483

   484

	if (n == 0) return; // heap is empty so nothing to do?

   485

   486

	// copy the last item to index 0. we use it as base for heapify.

   487

	ARR(1) = ARR(n+1);

   488

   489

	while ((j=i*2) <= n) {

   490

		// figure out which is smaller of the children.

   491

		if (j != n && ARR(j).priority > ARR(j+1).priority)

   492

			j++; // right item is smaller

   493

   494

		assert(i <= n && j <= n);

   495

		if (ARR(i).priority <= ARR(j).priority)

   496

			break; // base elem smaller than smallest, done!

   497

   498

		// swap parent with the child

   499

		si = ARR(i); ARR(i) = ARR(j); ARR(j) = si;

   500

		i = j;

   501

	}

   502

}

   503

   504

// mark a tile as visited and store the length of the path.

   505

// if we already had a better path to this tile, return false.

   506

// otherwise return true.