1

/** @file

     2

 * All actions handling saving and loading goes on in this file. The general actions

     3

 * are as follows for saving a game (loading is analogous):

     4

 * <ol>

     5

 * <li>initialize the writer by creating a temporary memory-buffer for it

     6

 * <li>go through all to-be saved elements, each 'chunk' (ChunkHandler) prefixed by a label

     7

 * <li>use their description array (SaveLoad) to know what elements to save and in what version

     8

 *    of the game it was active (used when loading)

     9

 * <li>write all data byte-by-byte to the temporary buffer so it is endian-safe

    10

 * <li>when the buffer is full; flush it to the output (eg save to file) (_sl.buf, _sl.bufp, _sl.bufe)

    11

 * <li>repeat this until everything is done, and flush any remaining output to file

    12

 * </ol>

    13

 * @see ChunkHandler

    14

 * @see SaveLoad

    15

 */

    16

#include "stdafx.h"

    17

#include "openttd.h"

    18

#include "debug.h"

    19

#include "vehicle.h"

    20

#include "station.h"

    21

#include "town.h"

    22

#include "player.h"

    23

#include "saveload.h"

    24

    25

enum {

    26

	SAVEGAME_MAJOR_VERSION = 15,

    27

	SAVEGAME_MINOR_VERSION = 0,

    28

    29

	SAVEGAME_LOADABLE_VERSION = (SAVEGAME_MAJOR_VERSION << 8) + SAVEGAME_MINOR_VERSION

    30

};

    31

    32

enum NeedLengthValues {NL_NONE = 0, NL_WANTLENGTH = 1, NL_CALCLENGTH = 2};

    33

    34

SaverLoader _sl;

    35

    36

/**

    37

 * Fill the input buffer by reading from the file with the given reader

    38

 */

    39

static void SlReadFill(void)

    40

{

    41

	uint len = _sl.read_bytes();

    42

	assert(len != 0);

    43

    44

	_sl.bufp = _sl.buf;

    45

	_sl.bufe = _sl.buf + len;

    46

	_sl.offs_base += len;

    47

}

    48

    49

static inline uint32 SlGetOffs(void) {return _sl.offs_base - (_sl.bufe - _sl.bufp);}

    50

    51

/** Flush the output buffer by writing to disk with the given reader.

    52

 * If the buffer pointer has not yet been set up, set it up now. Usually

    53

 * only called when the buffer is full, or there is no more data to be processed

    54

 */

    55

static void SlWriteFill(void)

    56

{

    57

	// flush the buffer to disk (the writer)

    58

	if (_sl.bufp != NULL) {

    59

		uint len = _sl.bufp - _sl.buf;

    60

		_sl.offs_base += len;

    61

		if (len) _sl.write_bytes(len);

    62

	}

    63

    64

	/* All the data from the buffer has been written away, rewind to the beginning

    65

	* to start reading in more data */

    66

	_sl.bufp = _sl.buf;

    67

	_sl.bufe = _sl.buf + _sl.bufsize;

    68

}

    69

    70

/** Error handler, calls longjmp to simulate an exception.

    71

 * @todo this was used to have a central place to handle errors, but it is

    72

 * pretty ugly, and seriously interferes with any multithreaded approaches */

    73

static void NORETURN SlError(const char *msg)

    74

{

    75

	_sl.excpt_msg = msg;

    76

	longjmp(_sl.excpt, 0);

    77

}

    78

    79

/** Read in a single byte from file. If the temporary buffer is full,

    80

 * flush it to its final destination

    81

 * @return return the read byte from file

    82

 */

    83

static inline int SlReadByteInternal(void)

    84

{

    85

	if (_sl.bufp == _sl.bufe) SlReadFill();

    86

	return *_sl.bufp++;

    87

}

    88

    89

/** Wrapper for SlReadByteInternal */

    90

int SlReadByte(void) {return SlReadByteInternal();}

    91

    92

/** Write away a single byte from memory. If the temporary buffer is full,

    93

 * flush it to its destination (file)

    94

 * @param b the byte that is currently written

    95

 */

    96

static inline void SlWriteByteInternal(byte b)

    97

{

    98

	if (_sl.bufp == _sl.bufe) SlWriteFill();

    99

	*_sl.bufp++ = b;

   100

}

   101

   102

/** Wrapper for SlWriteByteInternal */

   103

void SlWriteByte(byte b) {SlWriteByteInternal(b);}

   104

   105

static inline int SlReadUint16(void)

   106

{

   107

	int x = SlReadByte() << 8;

   108

	return x | SlReadByte();

   109

}

   110

   111

static inline uint32 SlReadUint32(void)

   112

{

   113

	uint32 x = SlReadUint16() << 16;

   114

	return x | SlReadUint16();

   115

}

   116

   117

static inline uint64 SlReadUint64(void)

   118

{

   119

	uint32 x = SlReadUint32();

   120

	uint32 y = SlReadUint32();

   121

	return (uint64)x << 32 | y;

   122

}

   123

   124

static inline void SlWriteUint16(VarType v)

   125

{

   126

	SlWriteByte((byte)(v >> 8));

   127

	SlWriteByte((byte)v);

   128

}

   129

   130

static inline void SlWriteUint32(uint32 v)

   131

{

   132

	SlWriteUint16((uint16)(v >> 16));

   133

	SlWriteUint16((uint16)v);

   134

}

   135

   136

static inline void SlWriteUint64(uint64 x)

   137

{

   138

	SlWriteUint32((uint32)(x >> 32));

   139

	SlWriteUint32((uint32)x);

   140

}

   141

   142

/**

   143

 * Read in the header descriptor of an object or an array.

   144

 * If the highest bit is set (7), then the index is bigger than 127

   145

 * elements, so use the next byte to read in the real value.

   146

 * The actual value is then both bytes added with the first shifted

   147

 * 8 bits to the left, and dropping the highest bit (which only indicated a big index).

   148

 * x = ((x & 0x7F) << 8) + SlReadByte();

   149

 * @return Return the value of the index

   150

 */

   151

static uint SlReadSimpleGamma(void)

   152

{

   153

	uint i = SlReadByte();

   154

	if (HASBIT(i, 7)) {

   155

		i &= ~0x80;

   156

		if (HASBIT(i, 6)) {

   157

			i &= ~0x40;

   158

			if (HASBIT(i, 5)) {

   159

				i &= ~0x20;

   160

				if (HASBIT(i, 4))

   161

					SlError("Unsupported gamma");

   162

				i = (i << 8) | SlReadByte();

   163

			}

   164

			i = (i << 8) | SlReadByte();

   165

		}

   166

		i = (i << 8) | SlReadByte();

   167

	}

   168

	return i;

   169

}

   170

   171

/**

   172

 * Write the header descriptor of an object or an array.

   173

 * If the element is bigger than 127, use 2 bytes for saving

   174

 * and use the highest byte of the first written one as a notice

   175

 * that the length consists of 2 bytes, etc.. like this:

   176

 * 0xxxxxxx

   177

 * 10xxxxxx xxxxxxxx

   178

 * 110xxxxx xxxxxxxx xxxxxxxx

   179

 * 1110xxxx xxxxxxxx xxxxxxxx xxxxxxxx

   180

 * @param i Index being written

   181

 */

   182

   183

static void SlWriteSimpleGamma(uint i)

   184

{

   185

	if (i >= (1 << 7)) {

   186

		if (i >= (1 << 14)) {

   187

			if (i >= (1 << 21)) {

   188

				assert(i < (1 << 28));

   189

				SlWriteByte((byte)0xE0 | (i>>24));

   190

				SlWriteByte((byte)(i>>16));

   191

			} else {

   192

				SlWriteByte((byte)0xC0 | (i>>16));

   193

			}

   194

			SlWriteByte((byte)(i>>8));

   195

		} else {

   196

			SlWriteByte((byte)(0x80 | (i>>8)));

   197

		}

   198

	}

   199

	SlWriteByte(i);

   200

}

   201

   202

/** Return how many bytes used to encode a gamma value */

   203

static inline uint SlGetGammaLength(uint i) {

   204

	return 1 + (i >= (1 << 7)) + (i >= (1 << 14)) + (i >= (1 << 21));

   205

}

   206

   207

static inline int SlReadSparseIndex(void) {return SlReadSimpleGamma();}

   208

static inline void SlWriteSparseIndex(uint index) {SlWriteSimpleGamma(index);}

   209

   210

static inline int SlReadArrayLength(void) {return SlReadSimpleGamma();}

   211

static inline void SlWriteArrayLength(uint length) {SlWriteSimpleGamma(length);}

   212

   213

void SlSetArrayIndex(uint index)

   214

{

   215

	_sl.need_length = NL_WANTLENGTH;

   216

	_sl.array_index = index;

   217

}

   218

   219

/**

   220

 * Iterate through the elements of an array and read the whole thing

   221

 * @return The index of the object, or -1 if we have reached the end of current block

   222

 */

   223

int SlIterateArray(void)

   224

{

   225

	int index;

   226

	static uint32 next_offs;

   227

   228

	/* After reading in the whole array inside the loop

   229

	 * we must have read in all the data, so we must be at end of current block. */

   230

	assert(next_offs == 0 || SlGetOffs() == next_offs);

   231

   232

	while (true) {

   233

		uint length = SlReadArrayLength();

   234

		if (length == 0) {

   235

			next_offs = 0;

   236

			return -1;

   237

		}

   238

   239

		_sl.obj_len = --length;

   240

		next_offs = SlGetOffs() + length;

   241

   242

		switch (_sl.block_mode) {

   243

		case CH_SPARSE_ARRAY: index = SlReadSparseIndex(); break;

   244

		case CH_ARRAY:        index = _sl.array_index++; break;

   245

		default:

   246

			DEBUG(misc, 0) ("SlIterateArray: error");

   247

			return -1; // error

   248

		}

   249

   250

		if (length != 0) return index;

   251

	}

   252

}

   253

   254

/**

   255

 * Sets the length of either a RIFF object or the number of items in an array.

   256

 * This lets us load an object or an array of arbitrary size

   257

 * @param length The length of the sought object/array

   258

 */

   259

void SlSetLength(size_t length)

   260

{

   261

	switch (_sl.need_length) {

   262

	case NL_WANTLENGTH:

   263

		_sl.need_length = NL_NONE;

   264

		switch (_sl.block_mode) {

   265

		case CH_RIFF:

   266

			// Ugly encoding of >16M RIFF chunks

   267

			// The lower 24 bits are normal

   268

			// The uppermost 4 bits are bits 24:27

   269

			assert(length < (1<<28));

   270

			SlWriteUint32((length & 0xFFFFFF) | ((length >> 24) << 28));

   271

			break;

   272

		case CH_ARRAY:

   273

			assert(_sl.last_array_index <= _sl.array_index);

   274

			while (++_sl.last_array_index <= _sl.array_index)

   275

				SlWriteArrayLength(1);

   276

			SlWriteArrayLength(length + 1);

   277

			break;

   278

		case CH_SPARSE_ARRAY:

   279

			SlWriteArrayLength(length + 1 + SlGetGammaLength(_sl.array_index)); // Also include length of sparse index.

   280

			SlWriteSparseIndex(_sl.array_index);

   281

			break;

   282

		default: NOT_REACHED();

   283

		} break;

   284

	case NL_CALCLENGTH:

   285

		_sl.obj_len += length;

   286

		break;

   287

	}

   288

}

   289

   290

/**

   291

 * Save/Load bytes. These do not need to be converted to Little/Big Endian

   292

 * so directly write them or read them to/from file

   293

 * @param ptr The source or destination of the object being manipulated

   294

 * @param length number of bytes this fast CopyBytes lasts

   295

 */

   296

static void SlCopyBytes(void *ptr, size_t length)

   297

{

   298

	byte *p = (byte*)ptr;

   299

   300

	if (_sl.save) {

   301

		for (; length != 0; length--) {SlWriteByteInternal(*p++);}

   302

	} else {

   303

		for (; length != 0; length--) {*p++ = SlReadByteInternal();}

   304

	}

   305

}

   306

   307

#if 0

   308

/**

   309

 * Read in bytes from the file/data structure but don't do

   310

 * anything with them

   311

 * NOTICE: currently unused

   312

 * @param length The amount of bytes that is being treated this way

   313

 */

   314

static inline void SlSkipBytes(size_t length)

   315

{

   316

	for (; length != 0; length--)

   317

		SlReadByte();

   318

}

   319

#endif

   320

   321

/* Get the length of the current object */

   322

uint SlGetFieldLength(void) {return _sl.obj_len;}

   323

   324

/**

   325

 * Handle all conversion and typechecking of variables here.

   326

 * In the case of saving, read in the actual value from the struct

   327

 * and then write them to file, endian safely. Loading a value

   328

 * goes exactly the opposite way

   329

 * @param ptr The object being filled/read

   330

 * @param conv @VarType type of the current element of the struct

   331

 */

   332

static void SlSaveLoadConv(void *ptr, VarType conv)

   333

{

   334

	int64 x = 0;

   335

   336

	if (_sl.save) { /* SAVE values */

   337

		/* Read a value from the struct. These ARE endian safe. */

   338

		switch ((conv >> 4) & 0xF) {

   339

		case SLE_VAR_I8   >> 4: x = *(int8*)ptr; break;

   340

		case SLE_VAR_U8   >> 4: x = *(byte*)ptr; break;

   341

		case SLE_VAR_I16  >> 4: x = *(int16*)ptr; break;

   342

		case SLE_VAR_U16  >> 4: x = *(uint16*)ptr; break;

   343

		case SLE_VAR_I32  >> 4: x = *(int32*)ptr; break;

   344

		case SLE_VAR_U32  >> 4: x = *(uint32*)ptr; break;

   345

		case SLE_VAR_I64  >> 4: x = *(int64*)ptr; break;

   346

		case SLE_VAR_U64  >> 4: x = *(uint64*)ptr; break;

   347

		case SLE_VAR_NULL >> 4: x = 0; break;

   348

		default: NOT_REACHED();

   349

		}

   350

   351

		// Write the value to the file and check if its value is in the desired range

   352

		switch (conv & 0xF) {

   353

		case SLE_FILE_I8: assert(x >= -128 && x <= 127);     SlWriteByte(x);break;

   354

		case SLE_FILE_U8: assert(x >= 0 && x <= 255);        SlWriteByte(x);break;

   355

		case SLE_FILE_I16:assert(x >= -32768 && x <= 32767); SlWriteUint16(x);break;

   356

		case SLE_FILE_STRINGID:

   357

		case SLE_FILE_U16:assert(x >= 0 && x <= 65535);      SlWriteUint16(x);break;

   358

		case SLE_FILE_I32: case SLE_FILE_U32:                SlWriteUint32((uint32)x);break;

   359

		case SLE_FILE_I64: case SLE_FILE_U64:                SlWriteUint64(x);break;

   360

		default: NOT_REACHED();

   361

		}

   362

	} else { /* LOAD values */

   363

   364

		// Read a value from the file

   365

		switch (conv & 0xF) {

   366

		case SLE_FILE_I8:  x = (int8)SlReadByte(); break;

   367

		case SLE_FILE_U8:  x = (byte)SlReadByte(); break;

   368

		case SLE_FILE_I16: x = (int16)SlReadUint16(); break;

   369

		case SLE_FILE_U16: x = (uint16)SlReadUint16(); break;

   370

		case SLE_FILE_I32: x = (int32)SlReadUint32(); break;

   371

		case SLE_FILE_U32: x = (uint32)SlReadUint32(); break;

   372

		case SLE_FILE_I64: x = (int64)SlReadUint64(); break;

   373

		case SLE_FILE_U64: x = (uint64)SlReadUint64(); break;

   374

		case SLE_FILE_STRINGID: x = RemapOldStringID((uint16)SlReadUint16()); break;

   375

		default: NOT_REACHED();

   376

		}

   377

   378

		/* Write The value to the struct. These ARE endian safe. */

   379

		switch ((conv >> 4) & 0xF) {

   380

		case SLE_VAR_I8   >> 4:  *(int8*)ptr = x; break;

   381

		case SLE_VAR_U8   >> 4:  *(byte*)ptr = x; break;

   382

		case SLE_VAR_I16  >> 4: *(int16*)ptr = x; break;

   383

		case SLE_VAR_U16  >> 4: *(uint16*)ptr = x; break;

   384

		case SLE_VAR_I32  >> 4: *(int32*)ptr = x; break;

   385

		case SLE_VAR_U32  >> 4: *(uint32*)ptr = x; break;

   386

		case SLE_VAR_I64  >> 4: *(int64*)ptr = x; break;

   387

		case SLE_VAR_U64  >> 4: *(uint64*)ptr = x; break;

   388

		case SLE_VAR_NULL >> 4: break;

   389

		default: NOT_REACHED();

   390

		}

   391

	}

   392

}

   393

   394

/* Length in bytes of the various datatypes in a savefile. These

   395

 * sizes are guaranteed by assert_compiles in stdafx.h */

   396

static const byte _conv_lengths[] = {1, 1, 2, 2, 4, 4, 8, 8, 2};

   397

   398

/**

   399

 * Return the size in bytes of a certain type of normal/atomic variable

   400

 * @param var The variable the size is being asked of (NOTICE: unused)

   401

 * @param conv @VarType type of variable that is used for calculating the size

   402

 * @return Return the size of this type in byes

   403

 */

   404

static inline size_t SlCalcConvLen(const void *var, VarType conv) {return _conv_lengths[conv & 0xF];}

   405

   406

/**

   407

 * Return the size in bytes of a reference (pointer)

   408

 */

   409

static inline size_t SlCalcRefLen(void) {return 2;}

   410

   411

/**

   412

 * Return the size in bytes of a certain type of atomic array

   413

 * @param array The variable the size is being asked of (NOTICE: unused)

   414

 * @param length The length of the array counted in elements

   415

 * @param conv @VarType type of the variable that is used in calculating the size

   416

 */

   417

static inline size_t SlCalcArrayLen(const void *array, uint length, VarType conv) {return _conv_lengths[conv & 0xF] * length;}

   418

   419

/**

   420

 * Save/Load an array.

   421

 * @param array The array being manipulated

   422

 * @param length The length of the array in elements

   423

 * @param conv @VarType type of the atomic array (int, byte, uint64, etc.)

   424

 */

   425

void SlArray(void *array, uint length, VarType conv)

   426

{

   427

	static const byte conv_mem_size[] = {1, 1, 2, 2, 4, 4, 8, 8, 0};

   428

   429

	// Automatically calculate the length?

   430

	if (_sl.need_length != NL_NONE) {

   431

		SlSetLength(SlCalcArrayLen(array, length, conv));

   432

		// Determine length only?

   433

		if (_sl.need_length == NL_CALCLENGTH)

   434

			return;

   435

	}

   436

   437

	/* NOTICE - handle some buggy stuff, in really old versions everything was saved

   438

	 * as a byte-type. So detect this, and adjust array size accordingly */

   439

	if (!_sl.save && _sl.version == 0) {

   440

		if (conv == SLE_INT16 || conv == SLE_UINT16 || conv == SLE_STRINGID) {

   441

			length *= 2; // int16, uint16 and StringID are 2 bytes in size

   442

			conv = SLE_INT8;

   443

		} else if (conv == SLE_INT32 || conv == SLE_UINT32) {

   444

			length *= 4; // int32 and uint32 are 4 bytes in size

   445

			conv = SLE_INT8;

   446

		}

   447

	}

   448

   449

	/* If the size of elements is 1 byte, no special conversion is needed,

   450

	 * use specialized copy-to-copy function to speed up things */

   451

	if (conv == SLE_INT8 || conv == SLE_UINT8) {

   452

		SlCopyBytes(array, length);

   453

	} else {

   454

		byte *a = (byte*)array;

   455

		for (; length != 0; length --) {

   456

			SlSaveLoadConv(a, conv);

   457

			a += conv_mem_size[(conv >> 4) & 0xF]; // get size

   458

		}

   459

	}

   460

}

   461

   462

/**

   463

 * Calculate the size of an object.

   464

 * @param object Object that needs its length calculated

   465

 * @param sld The @SaveLoad description of the object so we know how to manipulate it

   466

 */

   467

static size_t SlCalcObjLength(void *object, const SaveLoad *sld)

   468

{

   469

	size_t length = 0;

   470

   471

	// Need to determine the length and write a length tag.

   472

	for (; sld->cmd != SL_END; sld++) {

   473

		if (sld->cmd < SL_WRITEBYTE) {

   474

			if (HASBIT(sld->cmd, 2)) {

   475

				// check if the field is used in the current savegame version

   476

				if (_sl.version < sld->version_from || _sl.version > sld->version_to)

   477

					continue;

   478

			}

   479

   480

			switch (sld->cmd) {

   481

			case SL_VAR: case SL_CONDVAR: /* Normal Variable */

   482

				length += SlCalcConvLen(NULL, sld->type); break;

   483

			case SL_REF: case SL_CONDREF:  /* Reference variable */

   484

				length += SlCalcRefLen(); break;

   485

			case SL_ARR: case SL_CONDARR: /* Array */

   486

				length += SlCalcArrayLen(NULL, sld->length, sld->type); break;

   487

			default: NOT_REACHED();

   488

			}

   489

		} else if (sld->cmd == SL_WRITEBYTE) {

   490

			length++; // a byte is logically of size 1

   491

		} else if (sld->cmd == SL_INCLUDE) {

   492

			length += SlCalcObjLength(NULL, _sl.includes[sld->version_from]);

   493

		} else

   494

			assert(sld->cmd == SL_END);

   495

	}

   496

	return length;

   497

}

   498