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

	if (IsTileType(tile, MP_TUNNELBRIDGE)) {

   262

		if (IsTunnel(tile)) {

   263

			if (GetTunnelDirection(tile) != direction ||

   264

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

   265

				return;

   266

			}

   267

			tile = SkipToEndOfTunnel(tpf, tile, direction);

   268

		} else {

   269

			TileIndex tile_end;

   270

			if (GetBridgeRampDirection(tile) != direction ||

   271

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

   272

				return;

   273

			}

   274

			//fprintf(stderr, "%s: Planning over bridge\n", __func__);

   275

			// TODO doesn't work - WHAT doesn't work?

   276

			TPFSetTileBit(tpf, tile, 14);

   277

			tile_end = GetOtherBridgeEnd(tile);

   278

			tpf->rd.cur_length += DistanceManhattan(tile, tile_end);

   279

			tile = tile_end;

   280

			TPFSetTileBit(tpf, tile, 14);

   281

		}

   282

	}

   283

	tile += TileOffsByDiagDir(direction);

   284

   285

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

   286

	if (tpf->tracktype == TRANSPORT_RAIL) {

   287

		// don't enter train depot from the back

   288

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

   289

   290

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

   291

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

   292

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

   293

	}

   294

   295

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

   296

	if (tpf->tracktype == TRANSPORT_ROAD) {

   297

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

   298

		// don't enter road stop from the back

   299

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

   300

		// don't enter road depot from the back

   301

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

   302

	}

   303

   304

	/* Check if the new tile is a tunnel or bridge head and that the direction

   305

	 * and transport type match */

   306

	if (IsTileType(tile, MP_TUNNELBRIDGE)) {

   307

		if (IsTunnel(tile)) {

   308

			if (GetTunnelDirection(tile) != direction ||

   309

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

   310

				return;

   311

			}

   312

		} else if (IsBridge(tile)) {

   313

			if (GetBridgeRampDirection(tile) != direction ||

   314

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

   315

				return;

   316

			}

   317

		}

   318

	}

   319

   320

	tpf->rd.cur_length++;

   321

   322

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

   323

   324

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

   325

		bits &= _tpfmode1_and[direction];

   326

		bits = bits | (bits>>8);

   327

	}

   328

	bits &= 0xBF;

   329

   330

	if (bits != 0) {

   331

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

   332

			do {

   333

				i = FIND_FIRST_BIT(bits);

   334

				bits = KILL_FIRST_BIT(bits);

   335

   336

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

   337

				rd = tpf->rd;

   338

   339

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

   340

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

   341

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

   342

				}

   343

				tpf->rd = rd;

   344

			} while (bits != 0);

   345

		}

   346

	}

   347

   348

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

   349

	 * seems to go in 2 directions simultaneously */

   350

   351

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

   352

	 * stack space dramatically. */

   353

   354

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

   355

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

   356

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

   357

	if (tpf->hasbit_13)

   358

		return;

   359

   360

	direction = ReverseDiagDir(direction);

   361

	tile += TileOffsByDiagDir(direction);

   362

   363

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

   364

	bits |= (bits >> 8);

   365

   366

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

   367

		bits &= _bits_mask[direction];

   368

	}

   369

   370

	bits &= 0xBF;

   371

	if (bits == 0)

   372

		return;

   373

   374

	do {

   375

		i = FIND_FIRST_BIT(bits);

   376

		bits = KILL_FIRST_BIT(bits);

   377

   378

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

   379

		rd = tpf->rd;

   380

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

   381

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

   382

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

   383

		}

   384

		tpf->rd = rd;

   385

	} while (bits != 0);

   386

}

   387

   388

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

   389

{

   390

	TrackPathFinder tpf;

   391

   392

	assert(direction < 4);

   393

   394

	/* initialize path finder variables */

   395

	tpf.userdata = data;

   396

	tpf.enum_proc = enum_proc;

   397

	tpf.new_link = tpf.links;

   398

	tpf.num_links_left = lengthof(tpf.links);

   399

   400

	tpf.rd.cur_length = 0;

   401

	tpf.rd.depth = 0;

   402

	tpf.rd.pft_var6 = 0;

   403

   404

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

   405

   406

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

   407

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

   408

   409

   410

	tpf.tracktype = (byte)flags;

   411

   412

	if (HASBIT(flags, 11)) {

   413

		tpf.rd.pft_var6 = 0xFF;

   414

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

   415

		TPFMode2(&tpf, tile, direction);

   416

	} else {

   417

		/* clear the hash_heads */

   418

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

   419

		TPFMode1(&tpf, tile, direction);

   420

	}

   421

   422

	if (after_proc != NULL)

   423

		after_proc(&tpf);

   424

}

   425

   426

typedef struct {

   427

	TileIndex tile;

   428

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

   429

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

   430

	byte track;

   431

	byte depth;

   432

	byte state;

   433

	byte first_track;

   434

} StackedItem;

   435

   436

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

   437

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

   438

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

   439

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

   440

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

   441

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

   442

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

   443

};

   444

   445

typedef struct HashLink {

   446

	TileIndex tile;

   447

	uint16 typelength;

   448

	uint16 next;

   449

} HashLink;

   450

   451

typedef struct {

   452

	NTPEnumProc *enum_proc;

   453

	void *userdata;

   454

	TileIndex dest;

   455

   456

	TransportType tracktype;

   457

	RailTypeMask railtypes;

   458

	uint maxlength;

   459

   460

	HashLink *new_link;

   461

	uint num_links_left;

   462

   463

	uint nstack;

   464

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

   465

   466

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

   467

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

   468

   469

	HashLink links[0x400]; // hash links

   470

   471

} NewTrackPathFinder;

   472

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

   473

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

   474

   475

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

   476

   477

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

   478

// move it down to the proper position

   479

static inline void HeapifyUp(NewTrackPathFinder *tpf)

   480

{

   481

	StackedItem si;

   482

	int i = ++tpf->nstack;

   483

   484

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

   485

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

   486

		// swap the child item and the parent item.

   487

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

   488

		i>>=1;

   489

	}

   490

}

   491

   492

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

   493

static inline void HeapifyDown(NewTrackPathFinder *tpf)

   494

{

   495

	StackedItem si;

   496

	int i = 1, j;

   497

	int n;

   498

   499

	assert(tpf->nstack > 0);

   500

	n = --tpf->nstack;

   501

   502

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

   503

   504

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

   505

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

   506