aboutsummaryrefslogtreecommitdiff
path: root/engines/sci/engine/script.cpp
blob: 1f32e50b67132c72611cbb8c819526963d8480a6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */

#include "sci/sci.h"
#include "sci/resource.h"
#include "sci/util.h"
#include "sci/engine/features.h"
#include "sci/engine/state.h"
#include "sci/engine/kernel.h"
#include "sci/engine/script.h"

#include "common/util.h"

namespace Sci {

#define END Script_None

opcode_format g_opcode_formats[128][4] = {
	/*00*/
	{Script_None}, {Script_None}, {Script_None}, {Script_None},
	/*04*/
	{Script_None}, {Script_None}, {Script_None}, {Script_None},
	/*08*/
	{Script_None}, {Script_None}, {Script_None}, {Script_None},
	/*0C*/
	{Script_None}, {Script_None}, {Script_None}, {Script_None},
	/*10*/
	{Script_None}, {Script_None}, {Script_None}, {Script_None},
	/*14*/
	{Script_None}, {Script_None}, {Script_None}, {Script_SRelative, END},
	/*18*/
	{Script_SRelative, END}, {Script_SRelative, END}, {Script_SVariable, END}, {Script_None},
	/*1C*/
	{Script_SVariable, END}, {Script_None}, {Script_None}, {Script_Variable, END},
	/*20*/
	{Script_SRelative, Script_Byte, END}, {Script_Variable, Script_Byte, END}, {Script_Variable, Script_Byte, END}, {Script_Variable, Script_SVariable, Script_Byte, END},
	/*24 (24=ret)*/
	{Script_End}, {Script_Byte, END}, {Script_Invalid}, {Script_Invalid},
	/*28*/
	{Script_Variable, END}, {Script_Invalid}, {Script_Byte, END}, {Script_Variable, Script_Byte, END},
	/*2C*/
	{Script_SVariable, END}, {Script_SVariable, Script_Variable, END}, {Script_None}, {Script_Invalid},
	/*30*/
	{Script_None}, {Script_Property, END}, {Script_Property, END}, {Script_Property, END},
	/*34*/
	{Script_Property, END}, {Script_Property, END}, {Script_Property, END}, {Script_Property, END},
	/*38*/
	{Script_Property, END}, {Script_SRelative, END}, {Script_SRelative, END}, {Script_None},
	/*3C*/
	{Script_None}, {Script_None}, {Script_None}, {Script_Word},
	/*40-4F*/
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	/*50-5F*/
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	/*60-6F*/
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	/*70-7F*/
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END},
	{Script_Global, END}, {Script_Local, END}, {Script_Temp, END}, {Script_Param, END}
};
#undef END

// TODO: script_adjust_opcode_formats should probably be part of the
// constructor (?) of a VirtualMachine or a ScriptManager class.
void script_adjust_opcode_formats(EngineState *s) {
	// TODO: Check that this is correct
	if (g_sci->_features->detectLofsType() != SCI_VERSION_0_EARLY) {
		g_opcode_formats[op_lofsa][0] = Script_Offset;
		g_opcode_formats[op_lofss][0] = Script_Offset;
	}

#ifdef ENABLE_SCI32
	// In SCI32, some arguments are now words instead of bytes
	if (getSciVersion() >= SCI_VERSION_2) {
		g_opcode_formats[op_calle][2] = Script_Word;
		g_opcode_formats[op_callk][1] = Script_Word;
		g_opcode_formats[op_super][1] = Script_Word;
		g_opcode_formats[op_send][0] = Script_Word;
		g_opcode_formats[op_self][0] = Script_Word;
		g_opcode_formats[op_call][1] = Script_Word;
		g_opcode_formats[op_callb][1] = Script_Word;
	}
#endif
}

void SegManager::createClassTable() {
	Resource *vocab996 = _resMan->findResource(ResourceId(kResourceTypeVocab, 996), 1);

	if (!vocab996)
		error("SegManager: failed to open vocab 996");

	int totalClasses = vocab996->size >> 2;
	_classTable.resize(totalClasses);

	for (uint16 classNr = 0; classNr < totalClasses; classNr++) {
		uint16 scriptNr = READ_SCI11ENDIAN_UINT16(vocab996->data + classNr * 4 + 2);

		_classTable[classNr].reg = NULL_REG;
		_classTable[classNr].script = scriptNr;
	}

	_resMan->unlockResource(vocab996);
}

reg_t SegManager::getClassAddress(int classnr, ScriptLoadType lock, reg_t caller) {
	if (classnr == 0xffff)
		return NULL_REG;

	if (classnr < 0 || (int)_classTable.size() <= classnr || _classTable[classnr].script < 0) {
		error("[VM] Attempt to dereference class %x, which doesn't exist (max %x)", classnr, _classTable.size());
		return NULL_REG;
	} else {
		Class *the_class = &_classTable[classnr];
		if (!the_class->reg.segment) {
			getScriptSegment(the_class->script, lock);

			if (!the_class->reg.segment) {
				error("[VM] Trying to instantiate class %x by instantiating script 0x%x (%03d) failed;", classnr, the_class->script, the_class->script);
				return NULL_REG;
			}
		} else
			if (caller.segment != the_class->reg.segment)
				getScript(the_class->reg.segment)->incrementLockers();

		return the_class->reg;
	}
}

void SegManager::scriptInitialiseLocalsZero(SegmentId seg, int count) {
	Script *scr = getScript(seg);

	scr->_localsOffset = -count * 2; // Make sure it's invalid

	LocalVariables *locals = allocLocalsSegment(scr, count);
	if (locals) {
		for (int i = 0; i < count; i++)
			locals->_locals[i] = NULL_REG;
	}
}

void SegManager::scriptInitialiseLocals(reg_t location) {
	Script *scr = getScript(location.segment);
	unsigned int count;

	VERIFY(location.offset + 1 < (uint16)scr->getBufSize(), "Locals beyond end of script\n");

	if (getSciVersion() >= SCI_VERSION_1_1)
		count = READ_SCI11ENDIAN_UINT16(scr->_buf + location.offset - 2);
	else
		count = (READ_LE_UINT16(scr->_buf + location.offset - 2) - 4) >> 1;
	// half block size

	scr->_localsOffset = location.offset;

	if (!(location.offset + count * 2 + 1 < scr->getBufSize())) {
		warning("Locals extend beyond end of script: offset %04x, count %x vs size %x", location.offset, count, (uint)scr->getBufSize());
		count = (scr->getBufSize() - location.offset) >> 1;
	}

	LocalVariables *locals = allocLocalsSegment(scr, count);
	if (locals) {
		uint i;
		const byte *base = (const byte *)(scr->_buf + location.offset);

		for (i = 0; i < count; i++)
			locals->_locals[i] = make_reg(0, READ_SCI11ENDIAN_UINT16(base + i * 2));
	}
}

void SegManager::scriptInitialiseObjectsSci11(SegmentId seg) {
	Script *scr = getScript(seg);
	const byte *seeker = scr->_heapStart + 4 + READ_SCI11ENDIAN_UINT16(scr->_heapStart + 2) * 2;

	while (READ_SCI11ENDIAN_UINT16(seeker) == SCRIPT_OBJECT_MAGIC_NUMBER) {
		if (READ_SCI11ENDIAN_UINT16(seeker + 14) & kInfoFlagClass) {	// -info- selector
			int classpos = seeker - scr->_buf;
			int species = READ_SCI11ENDIAN_UINT16(seeker + 10);

			if (species < 0 || species >= (int)_classTable.size()) {
				error("Invalid species %d(0x%x) not in interval [0,%d) while instantiating script %d",
				          species, species, _classTable.size(), scr->_nr);
				return;
			}

			_classTable[species].reg.segment = seg;
			_classTable[species].reg.offset = classpos;
		}
		seeker += READ_SCI11ENDIAN_UINT16(seeker + 2) * 2;
	}

	seeker = scr->_heapStart + 4 + READ_SCI11ENDIAN_UINT16(scr->_heapStart + 2) * 2;
	while (READ_SCI11ENDIAN_UINT16(seeker) == SCRIPT_OBJECT_MAGIC_NUMBER) {
		reg_t reg = make_reg(seg, seeker - scr->_buf);
		Object *obj = scr->scriptObjInit(reg);

		// Copy base from species class, as we need its selector IDs
		obj->setSuperClassSelector(
			getClassAddress(obj->getSuperClassSelector().offset, SCRIPT_GET_LOCK, NULL_REG));

		// If object is instance, get -propDict- from class and set it for this object
		//  This is needed for ::isMemberOf() to work.
		// Example testcase - room 381 of sq4cd - if isMemberOf() doesn't work, talk-clicks on the robot will act like
		//                     clicking on ego
		if (!obj->isClass()) {
			reg_t classObject = obj->getSuperClassSelector();
			Object *classObj = getObject(classObject);
			obj->setPropDictSelector(classObj->getPropDictSelector());
		}

		// Set the -classScript- selector to the script number.
		// FIXME: As this selector is filled in at run-time, it is likely
		// that it is supposed to hold a pointer. The Obj::isKindOf method
		// uses this selector together with -propDict- to compare classes.
		// For the purpose of Obj::isKindOf, using the script number appears
		// to be sufficient.
		obj->setClassScriptSelector(make_reg(0, scr->_nr));

		seeker += READ_SCI11ENDIAN_UINT16(seeker + 2) * 2;
	}
}

void script_instantiate_sci0(Script *scr, int segmentId, SegManager *segMan) {
	int objType;
	uint32 objLength = 0;
	bool oldScriptHeader = (getSciVersion() == SCI_VERSION_0_EARLY);
	uint16 curOffset = oldScriptHeader ? 2 : 0;

	if (oldScriptHeader) {
		// Old script block
		// There won't be a localvar block in this case
		// Instead, the script starts with a 16 bit int specifying the
		// number of locals we need; these are then allocated and zeroed.
		int localsCount = READ_LE_UINT16(scr->_buf);
		if (localsCount)
			segMan->scriptInitialiseLocalsZero(segmentId, localsCount);
	}

	// Now do a first pass through the script objects to find the
	// local variable blocks

	do {
		objType = scr->getHeap(curOffset);
		if (!objType)
			break;

		objLength = scr->getHeap(curOffset + 2);
		curOffset += 4;		// skip header

		switch (objType) {
		case SCI_OBJ_LOCALVARS:
			segMan->scriptInitialiseLocals(make_reg(segmentId, curOffset));
			break;
		case SCI_OBJ_CLASS: {
			int classpos = curOffset - SCRIPT_OBJECT_MAGIC_OFFSET;
			int species = scr->getHeap(curOffset - SCRIPT_OBJECT_MAGIC_OFFSET + SCRIPT_SPECIES_OFFSET);
			if (species < 0 || species >= (int)segMan->classTableSize()) {
				if (species == (int)segMan->classTableSize()) {
					// Happens in the LSL2 demo
					warning("Applying workaround for an off-by-one invalid species access");
					segMan->resizeClassTable(segMan->classTableSize() + 1);
				} else {
					error("Invalid species %d(0x%x) not in interval "
							  "[0,%d) while instantiating script at segment %d\n",
							  species, species, segMan->classTableSize(),
							  segmentId);
					return;
				}
			}

			segMan->setClassOffset(species, make_reg(segmentId, classpos));
			// Set technical class position-- into the block allocated for it
		}
		break;

		default:
			break;
		}

		curOffset += objLength - 4;
	} while (objType != 0 && curOffset < scr->getScriptSize() - 2);

	// And now a second pass to adjust objects and class pointers, and the general pointers
	objLength = 0;
	curOffset = oldScriptHeader ? 2 : 0;

	do {
		objType = scr->getHeap(curOffset);
		if (!objType)
			break;

		objLength = scr->getHeap(curOffset + 2);
		curOffset += 4;		// skip header

		reg_t addr = make_reg(segmentId, curOffset);

		switch (objType) {
		case SCI_OBJ_CODE:
			scr->scriptAddCodeBlock(addr);
			break;
		case SCI_OBJ_OBJECT:
		case SCI_OBJ_CLASS: { // object or class?
			Object *obj = scr->scriptObjInit(addr);
			obj->initSpecies(segMan, addr);

			if (!obj->initBaseObject(segMan, addr)) {
				warning("Failed to locate base object for object at %04X:%04X; skipping", PRINT_REG(addr));
				scr->scriptObjRemove(addr);
			}
		} // if object or class
		break;
		default:
			break;
		}

		curOffset += objLength - 4;
	} while (objType != 0 && curOffset < scr->getScriptSize() - 2);
}

int script_instantiate(ResourceManager *resMan, SegManager *segMan, int scriptNum) {
	SegmentId segmentId = segMan->getScriptSegment(scriptNum);
	Script *scr = segMan->getScriptIfLoaded(segmentId);
	if (scr) {
		if (!scr->isMarkedAsDeleted()) {
			scr->incrementLockers();
			return segmentId;
		} else {
			scr->freeScript();
		}
	} else {
		scr = segMan->allocateScript(scriptNum, &segmentId);
	}

	scr->init(scriptNum, resMan);
	scr->load(resMan);

	if (getSciVersion() >= SCI_VERSION_1_1) {
		int heapStart = scr->getScriptSize();
		segMan->scriptInitialiseLocals(make_reg(segmentId, heapStart + 4));
		segMan->scriptInitialiseObjectsSci11(segmentId);
		scr->relocate(make_reg(segmentId, READ_SCI11ENDIAN_UINT16(scr->_heapStart)));
	} else {
		script_instantiate_sci0(scr, segmentId, segMan);
		byte *relocationBlock = scr->findBlock(SCI_OBJ_POINTERS);
		if (relocationBlock)
			scr->relocate(make_reg(segmentId, relocationBlock - scr->_buf + 4));
	}

	return segmentId;
}

void script_uninstantiate_sci0(SegManager *segMan, int script_nr, SegmentId seg) {
	bool oldScriptHeader = (getSciVersion() == SCI_VERSION_0_EARLY);
	reg_t reg = make_reg(seg, oldScriptHeader ? 2 : 0);
	int objType, objLength = 0;
	Script *scr = segMan->getScript(seg);

	// Make a pass over the object in order uninstantiate all superclasses

	do {
		reg.offset += objLength; // Step over the last checked object

		objType = scr->getHeap(reg.offset);
		if (!objType)
			break;
		objLength = scr->getHeap(reg.offset + 2);  // use SEG_UGET_HEAP ??

		reg.offset += 4; // Step over header

		if ((objType == SCI_OBJ_OBJECT) || (objType == SCI_OBJ_CLASS)) { // object or class?
			int superclass;

			reg.offset -= SCRIPT_OBJECT_MAGIC_OFFSET;

			superclass = scr->getHeap(reg.offset + SCRIPT_SUPERCLASS_OFFSET); // Get superclass...

			if (superclass >= 0) {
				int superclass_script = segMan->getClass(superclass).script;

				if (superclass_script == script_nr) {
					if (scr->getLockers())
						scr->decrementLockers();  // Decrease lockers if this is us ourselves
				} else
					script_uninstantiate(segMan, superclass_script);
				// Recurse to assure that the superclass lockers number gets decreased
			}

			reg.offset += SCRIPT_OBJECT_MAGIC_OFFSET;
		} // if object or class

		reg.offset -= 4; // Step back on header

	} while (objType != 0);
}

void script_uninstantiate(SegManager *segMan, int script_nr) {
	SegmentId segment = segMan->getScriptSegment(script_nr);
	Script *scr = segMan->getScriptIfLoaded(segment);

	if (!scr) {   // Is it already loaded?
		//warning("unloading script 0x%x requested although not loaded", script_nr);
		// This is perfectly valid SCI behaviour
		return;
	}

	scr->decrementLockers();   // One less locker

	if (scr->getLockers() > 0)
		return;

	// Free all classtable references to this script
	for (uint i = 0; i < segMan->classTableSize(); i++)
		if (segMan->getClass(i).reg.segment == segment)
			segMan->setClassOffset(i, NULL_REG);

	if (getSciVersion() < SCI_VERSION_1_1)
		script_uninstantiate_sci0(segMan, script_nr, segment);
	// FIXME: Add proper script uninstantiation for SCI 1.1

	if (scr->getLockers())
		return; // if xxx.lockers > 0

	// Otherwise unload it completely
	// Explanation: I'm starting to believe that this work is done by SCI itself.
	scr->markDeleted();

	debugC(kDebugLevelScripts, "Unloaded script 0x%x.", script_nr);

	return;
}


} // End of namespace Sci