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"

    20

#include "vehicle.h"

    21

#include "station.h"

    22

#include "town.h"

    23

#include "player.h"

    24

#include "saveload.h"

    25

#include "variables.h"

    26

    27

enum {

    28

	SAVEGAME_MAJOR_VERSION = 15,

    29

	SAVEGAME_MINOR_VERSION = 0,

    30

    31

	SAVEGAME_LOADABLE_VERSION = (SAVEGAME_MAJOR_VERSION << 8) + SAVEGAME_MINOR_VERSION

    32

};

    33

    34

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

    35

    36

SaverLoader _sl;

    37

    38

/**

    39

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

    40

 */

    41

static void SlReadFill(void)

    42

{

    43

	uint len = _sl.read_bytes();

    44

	assert(len != 0);

    45

    46

	_sl.bufp = _sl.buf;

    47

	_sl.bufe = _sl.buf + len;

    48

	_sl.offs_base += len;

    49

}

    50

    51

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

    52

    53

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

    54

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

    55

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

    56

 */

    57

static void SlWriteFill(void)

    58

{

    59

	// flush the buffer to disk (the writer)

    60

	if (_sl.bufp != NULL) {

    61

		uint len = _sl.bufp - _sl.buf;

    62

		_sl.offs_base += len;

    63

		if (len) _sl.write_bytes(len);

    64

	}

    65

    66

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

    67

	* to start reading in more data */

    68

	_sl.bufp = _sl.buf;

    69

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

    70

}

    71

    72

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

    73

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

    74

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

    75

static void NORETURN SlError(const char *msg)

    76

{

    77

	_sl.excpt_msg = msg;

    78

	longjmp(_sl.excpt, 0);

    79

}

    80

    81

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

    82

 * flush it to its final destination

    83

 * @return return the read byte from file

    84

 */

    85

static inline int SlReadByteInternal(void)

    86

{

    87

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

    88

	return *_sl.bufp++;

    89

}

    90

    91

/** Wrapper for SlReadByteInternal */

    92

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

    93

    94

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

    95

 * flush it to its destination (file)

    96

 * @param b the byte that is currently written

    97

 */

    98

static inline void SlWriteByteInternal(byte b)

    99

{

   100

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

   101

	*_sl.bufp++ = b;

   102

}

   103

   104

/** Wrapper for SlWriteByteInternal */

   105

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

   106

   107

static inline int SlReadUint16(void)

   108

{

   109

	int x = SlReadByte() << 8;

   110

	return x | SlReadByte();

   111

}

   112

   113

static inline uint32 SlReadUint32(void)

   114

{

   115

	uint32 x = SlReadUint16() << 16;

   116

	return x | SlReadUint16();

   117

}

   118

   119

static inline uint64 SlReadUint64(void)

   120

{

   121

	uint32 x = SlReadUint32();

   122

	uint32 y = SlReadUint32();

   123

	return (uint64)x << 32 | y;

   124

}

   125

   126

static inline void SlWriteUint16(uint16 v)

   127

{

   128

	SlWriteByte(GB(v, 8, 8));

   129

	SlWriteByte(GB(v, 0, 8));

   130

}

   131

   132

static inline void SlWriteUint32(uint32 v)

   133

{

   134

	SlWriteUint16(GB(v, 16, 16));

   135

	SlWriteUint16(GB(v,  0, 16));

   136

}

   137

   138

static inline void SlWriteUint64(uint64 x)

   139

{

   140

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

   141

	SlWriteUint32((uint32)x);

   142

}

   143

   144

/**

   145

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

   146

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

   147

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

   148

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

   149

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

   150

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

   151

 * @return Return the value of the index

   152

 */

   153

static uint SlReadSimpleGamma(void)

   154

{

   155

	uint i = SlReadByte();

   156

	if (HASBIT(i, 7)) {

   157

		i &= ~0x80;

   158

		if (HASBIT(i, 6)) {

   159

			i &= ~0x40;

   160

			if (HASBIT(i, 5)) {

   161

				i &= ~0x20;

   162

				if (HASBIT(i, 4))

   163

					SlError("Unsupported gamma");

   164

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

   165

			}

   166

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

   167

		}

   168

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

   169

	}

   170

	return i;

   171

}

   172

   173

/**

   174

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

   175

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

   176

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

   177

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

   178

 * 0xxxxxxx

   179

 * 10xxxxxx xxxxxxxx

   180

 * 110xxxxx xxxxxxxx xxxxxxxx

   181

 * 1110xxxx xxxxxxxx xxxxxxxx xxxxxxxx

   182

 * @param i Index being written

   183

 */

   184

   185

static void SlWriteSimpleGamma(uint i)

   186

{

   187

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

   188

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

   189

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

   190

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

   191

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

   192

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

   193

			} else {

   194

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

   195

			}

   196

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

   197

		} else {

   198

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

   199

		}

   200

	}

   201

	SlWriteByte(i);

   202

}

   203

   204

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

   205

static inline uint SlGetGammaLength(uint i) {

   206

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

   207

}

   208

   209

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

   210

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

   211

   212

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

   213

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

   214

   215

void SlSetArrayIndex(uint index)

   216

{

   217

	_sl.need_length = NL_WANTLENGTH;

   218

	_sl.array_index = index;

   219

}

   220

   221

/**

   222

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

   223

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

   224

 */

   225

int SlIterateArray(void)

   226

{

   227

	int index;

   228

	static uint32 next_offs;

   229

   230

	/* After reading in the whole array inside the loop

   231

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

   232

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

   233

   234

	while (true) {

   235

		uint length = SlReadArrayLength();

   236

		if (length == 0) {

   237

			next_offs = 0;

   238

			return -1;

   239

		}

   240

   241

		_sl.obj_len = --length;

   242

		next_offs = SlGetOffs() + length;

   243

   244

		switch (_sl.block_mode) {

   245

		case CH_SPARSE_ARRAY: index = SlReadSparseIndex(); break;

   246

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

   247

		default:

   248

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

   249

			return -1; // error

   250

		}

   251

   252

		if (length != 0) return index;

   253

	}

   254

}

   255

   256

/**

   257

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

   258

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

   259

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

   260

 */

   261

void SlSetLength(size_t length)

   262

{

   263

	switch (_sl.need_length) {

   264

	case NL_WANTLENGTH:

   265

		_sl.need_length = NL_NONE;

   266

		switch (_sl.block_mode) {

   267

		case CH_RIFF:

   268

			// Ugly encoding of >16M RIFF chunks

   269

			// The lower 24 bits are normal

   270

			// The uppermost 4 bits are bits 24:27

   271

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

   272

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

   273

			break;

   274

		case CH_ARRAY:

   275

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

   276

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

   277

				SlWriteArrayLength(1);

   278

			SlWriteArrayLength(length + 1);

   279

			break;

   280

		case CH_SPARSE_ARRAY:

   281

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

   282

			SlWriteSparseIndex(_sl.array_index);

   283

			break;

   284

		default: NOT_REACHED();

   285

		} break;

   286

	case NL_CALCLENGTH:

   287

		_sl.obj_len += length;

   288

		break;

   289

	}

   290

}

   291

   292

/**

   293

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

   294

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

   295

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

   296

 * @param length number of bytes this fast CopyBytes lasts

   297

 */

   298

static void SlCopyBytes(void *ptr, size_t length)

   299

{

   300

	byte *p = (byte*)ptr;

   301

   302

	if (_sl.save) {

   303

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

   304

	} else {

   305

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

   306

	}

   307

}

   308

   309

#if 0

   310

/**

   311

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

   312

 * anything with them

   313

 * NOTICE: currently unused

   314

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

   315

 */

   316

static inline void SlSkipBytes(size_t length)

   317

{

   318

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

   319

		SlReadByte();

   320

}

   321

#endif

   322

   323

/* Get the length of the current object */

   324

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

   325

   326

/**

   327

 * Handle all conversion and typechecking of variables here.

   328

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

   329

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

   330

 * goes exactly the opposite way

   331

 * @param ptr The object being filled/read

   332

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

   333

 */

   334

static void SlSaveLoadConv(void *ptr, VarType conv)

   335

{

   336

	int64 x = 0;

   337

   338

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

   339

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

   340

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

   341

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

   342

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

   343

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

   344

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

   345

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

   346

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

   347

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

   348

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

   349

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

   350

		default: NOT_REACHED();

   351

		}

   352

   353

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

   354

		switch (conv & 0xF) {

   355

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

   356

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

   357

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

   358

		case SLE_FILE_STRINGID:

   359

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

   360

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

   361

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

   362

		default: NOT_REACHED();

   363

		}

   364

	} else { /* LOAD values */

   365

   366

		// Read a value from the file

   367

		switch (conv & 0xF) {

   368

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

   369

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

   370

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

   371

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

   372

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

   373

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

   374

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

   375

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

   376

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

   377

		default: NOT_REACHED();

   378

		}

   379

   380

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

   381

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

   382

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

   383

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

   384

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

   385

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

   386

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

   387

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

   388

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

   389

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

   390

		case SLE_VAR_NULL >> 4: break;

   391

		default: NOT_REACHED();

   392

		}

   393

	}

   394

}

   395

   396

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

   397

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

   398

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

   399

   400

/**

   401

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

   402

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

   403

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

   404

 * @return Return the size of this type in byes

   405

 */

   406

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

   407

   408

/**

   409

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

   410

 */

   411

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

   412

   413

/**

   414

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

   415

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

   416

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

   417

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

   418

 */

   419

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

   420

   421

/**

   422

 * Save/Load an array.

   423

 * @param array The array being manipulated

   424

 * @param length The length of the array in elements

   425

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

   426

 */

   427

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

   428

{

   429

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

   430

   431

	// Automatically calculate the length?

   432

	if (_sl.need_length != NL_NONE) {

   433

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

   434

		// Determine length only?

   435

		if (_sl.need_length == NL_CALCLENGTH)

   436

			return;

   437

	}

   438

   439

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

   440

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

   441

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

   442

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

   443

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

   444

			conv = SLE_INT8;

   445

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

   446

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

   447

			conv = SLE_INT8;

   448

		}

   449

	}

   450

   451

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

   452

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

   453

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

   454

		SlCopyBytes(array, length);

   455

	} else {

   456

		byte *a = (byte*)array;

   457

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

   458

			SlSaveLoadConv(a, conv);

   459

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

   460

		}

   461

	}

   462

}

   463

   464

/**

   465

 * Calculate the size of an object.

   466

 * @param object Object that needs its length calculated

   467

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

   468

 */

   469

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

   470

{

   471

	size_t length = 0;

   472

   473

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

   474

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

   475

		if (sld->cmd < SL_WRITEBYTE) {

   476

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

   477

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

   478

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

   479

					continue;

   480

			}

   481

   482

			switch (sld->cmd) {

   483

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

   484

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

   485

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

   486

				length += SlCalcRefLen(); break;

   487

			case SL_ARR: case SL_CONDARR: /* Array */

   488

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

   489

			default: NOT_REACHED();

   490

			}

   491

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

   492

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

   493

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

   494

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

   495

		} else

   496

			assert(sld->cmd == SL_END);

   497

	}