aboutsummaryrefslogtreecommitdiff
path: root/engines/tinsel/heapmem.cpp
blob: 82fc3fd11a2808216fcc2a74909cc0e0b8bcda11 (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
466
467
468
469
470
/* 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.
 *
 * This file contains the handle based Memory Manager code.
 */

#include "tinsel/heapmem.h"
#include "tinsel/timers.h"	// For DwGetCurrentTime
#include "tinsel/tinsel.h"

namespace Tinsel {


#define	NUM_MNODES	192	// the number of memory management nodes (was 128, then 192)


// internal allocation flags
#define	DWM_USED		0x0001	///< the objects memory block is in use
#define	DWM_DISCARDED	0x0002	///< the objects memory block has been discarded
#define	DWM_LOCKED		0x0004	///< the objects memory block is locked
#define	DWM_SENTINEL	0x0008	///< the objects memory block is a sentinel


struct MEM_NODE {
	MEM_NODE *pNext;	// link to the next node in the list
	MEM_NODE *pPrev;	// link to the previous node in the list
	uint8 *pBaseAddr;	// base address of the memory object
	long size;		// size of the memory object
	uint32 lruTime;		// time when memory object was last accessed
	int flags;		// allocation attributes
};


// Specifies the total amount of memory required for DW1 demo, DW1, or DW2 respectively.
// Currently this is set at 5MB for the DW1 demo and DW1 and 10MB for DW2
// This could probably be reduced somewhat
// If the memory is not enough, the engine throws an "Out of memory" error in handle.cpp inside LockMem()
static const uint32 MemoryPoolSize[3] = {5 * 1024 * 1024, 5 * 1024 * 1024, 10 * 1024 * 1024};

// FIXME: Avoid non-const global vars


// list of all memory nodes
MEM_NODE g_mnodeList[NUM_MNODES];

// pointer to the linked list of free mnodes
static MEM_NODE *g_pFreeMemNodes;

// list of all fixed memory nodes
MEM_NODE g_s_fixedMnodesList[5];

// the mnode heap sentinel
static MEM_NODE g_heapSentinel;

//
static MEM_NODE *AllocMemNode();

#ifdef DEBUG
static void MemoryStats() {
	int usedNodes = 0;
	int allocedNodes = 0;
	int lockedNodes = 0;
	int lockedSize = 0;
	int totalSize = 0;

	const MEM_NODE *pHeap = &g_heapSentinel;
	MEM_NODE *pCur;

	for (pCur = pHeap->pNext; pCur != pHeap; pCur = pCur->pNext) {
		usedNodes++;
		totalSize += pCur->size;
		if (pCur->flags)
			allocedNodes++;
		if (pCur->flags & DWM_LOCKED) {
			lockedNodes++;
			lockedSize += pCur->size;
		}
	}

	debug("%d nodes used, %d alloced, %d locked; %d bytes locked, %d used",
			usedNodes, allocedNodes, lockedNodes, lockedSize, totalSize);
}
#endif

/**
 * Initializes the memory manager.
 */
void MemoryInit() {
	// place first node on free list
	g_pFreeMemNodes = g_mnodeList;

	// link all other objects after first
	memset(g_mnodeList, 0, sizeof(g_mnodeList));
	for (int i = 1; i < NUM_MNODES; i++) {
		g_mnodeList[i - 1].pNext = g_mnodeList + i;
	}

	// null the last mnode
	g_mnodeList[NUM_MNODES - 1].pNext = NULL;

	// clear list of fixed memory nodes
	memset(g_s_fixedMnodesList, 0, sizeof(g_s_fixedMnodesList));

	// set cyclic links to the sentinel
	g_heapSentinel.pPrev = &g_heapSentinel;
	g_heapSentinel.pNext = &g_heapSentinel;

	// flag sentinel as locked
	g_heapSentinel.flags = DWM_LOCKED | DWM_SENTINEL;

	// store the current heap size in the sentinel
	uint32 size = MemoryPoolSize[0];
	if (TinselVersion == TINSEL_V1) size = MemoryPoolSize[1];
	else if (TinselVersion == TINSEL_V2) size = MemoryPoolSize[2];
	g_heapSentinel.size = size;
}

/**
 * Deinitializes the memory manager.
 */
void MemoryDeinit() {
	const MEM_NODE *pHeap = &g_heapSentinel;
	MEM_NODE *pCur;

	pCur = g_s_fixedMnodesList;
	for (int i = 0; i < ARRAYSIZE(g_s_fixedMnodesList); ++i, ++pCur) {
		free(pCur->pBaseAddr);
		pCur->pBaseAddr = 0;
	}

	for (pCur = pHeap->pNext; pCur != pHeap; pCur = pCur->pNext) {
		free(pCur->pBaseAddr);
		pCur->pBaseAddr = 0;
	}
}


/**
 * Allocate a mnode from the free list.
 */
static MEM_NODE *AllocMemNode() {
	// get the first free mnode
	MEM_NODE *pMemNode = g_pFreeMemNodes;

	// make sure a mnode is available
	assert(pMemNode); // Out of memory nodes

	// the next free mnode
	g_pFreeMemNodes = pMemNode->pNext;

	// wipe out the mnode
	memset(pMemNode, 0, sizeof(MEM_NODE));

	// return new mnode
	return pMemNode;
}

/**
 * Return a mnode back to the free list.
 * @param pMemNode			Node of the memory object
 */
void FreeMemNode(MEM_NODE *pMemNode) {
	// validate mnode pointer
	assert(pMemNode >= g_mnodeList && pMemNode <= g_mnodeList + NUM_MNODES - 1);

	// place free list in mnode next
	pMemNode->pNext = g_pFreeMemNodes;

	// add mnode to top of free list
	g_pFreeMemNodes = pMemNode;
}


/**
 * Tries to make space for the specified number of bytes on the specified heap.
 * @param size			Number of bytes to free up
 * @return true if any blocks were discarded, false otherwise
 */
static bool HeapCompact(long size) {
	const MEM_NODE *pHeap = &g_heapSentinel;
	MEM_NODE *pCur, *pOldest;
	uint32 oldest;		// time of the oldest discardable block

	while (g_heapSentinel.size < size) {

		// find the oldest discardable block
		oldest = DwGetCurrentTime();
		pOldest = NULL;
		for (pCur = pHeap->pNext; pCur != pHeap; pCur = pCur->pNext) {
			if (pCur->flags == DWM_USED) {
				// found a non-discarded discardable block
				if (pCur->lruTime < oldest) {
					oldest = pCur->lruTime;
					pOldest = pCur;
				}
			}
		}

		if (pOldest)
			// discard the oldest block
			MemoryDiscard(pOldest);
		else
			// cannot discard any blocks
			return false;
	}

	// we have freed enough memory
	return true;
}

/**
 * Allocates the specified number of bytes from the heap.
 * @param flags			Allocation attributes
 * @param size			Number of bytes to allocate
 */
static MEM_NODE *MemoryAlloc(long size) {
	MEM_NODE *pHeap = &g_heapSentinel;

#ifdef SCUMM_NEED_ALIGNMENT
	const int alignPadding = sizeof(void *) - 1;
	size = (size + alignPadding) & ~alignPadding;	//round up to nearest multiple of sizeof(void *), this ensures the addresses that are returned are alignment-safe.
#endif

	// compact the heap to make up room for 'size' bytes, if necessary
	if (!HeapCompact(size))
		return 0;

	// success! we may allocate a new node of the right size

	// Allocate a node.
	MEM_NODE *pNode = AllocMemNode();

	// Allocate memory for the node.
	pNode->pBaseAddr = (byte *)malloc(size);

	// Verify that we got the memory.
	// TODO: If this fails, we should first try to compact the heap some further.
	assert(pNode->pBaseAddr);

	// Subtract size of new block from total
	g_heapSentinel.size -= size;

#ifdef DEBUG
	MemoryStats();
#endif

	// Set flags, LRU time and size
	pNode->flags = DWM_USED;
	pNode->lruTime = DwGetCurrentTime() + 1;
	pNode->size = size;

	// set mnode at the end of the list
	pNode->pPrev = pHeap->pPrev;
	pNode->pNext = pHeap;

	// fix links to this mnode
	pHeap->pPrev->pNext = pNode;
	pHeap->pPrev = pNode;

	return pNode;
}

/**
 * Allocate a discarded MEM_NODE. Actual memory can be assigned to it
 * by using MemoryReAlloc().
 */
MEM_NODE *MemoryNoAlloc() {
	MEM_NODE *pHeap = &g_heapSentinel;

	// chain a discarded node onto the end of the heap
	MEM_NODE *pNode = AllocMemNode();
	pNode->flags = DWM_USED | DWM_DISCARDED;
	pNode->lruTime = DwGetCurrentTime();
	pNode->size = 0;

	// set mnode at the end of the list
	pNode->pPrev = pHeap->pPrev;
	pNode->pNext = pHeap;

	// fix links to this mnode
	pHeap->pPrev->pNext = pNode;
	pHeap->pPrev = pNode;

	// return the discarded node
	return pNode;
}

/**
 * Allocate a fixed block of data.
 * @todo We really should keep track of the allocated pointers,
 *       so that we can discard them later on, when the engine quits.
 */
MEM_NODE *MemoryAllocFixed(long size) {

#ifdef SCUMM_NEED_ALIGNMENT
	const int alignPadding = sizeof(void *) - 1;
	size = (size + alignPadding) & ~alignPadding;	//round up to nearest multiple of sizeof(void *), this ensures the addresses that are returned are alignment-safe.
#endif

	// Search for a free entry in s_fixedMnodesList
	MEM_NODE *pNode = g_s_fixedMnodesList;
	for (int i = 0; i < ARRAYSIZE(g_s_fixedMnodesList); ++i, ++pNode) {
		if (!pNode->pBaseAddr) {
			pNode->pNext = 0;
			pNode->pPrev = 0;
			pNode->pBaseAddr = (byte *)malloc(size);
			pNode->size = size;
			pNode->lruTime = DwGetCurrentTime() + 1;
			pNode->flags = DWM_USED;

			// Subtract size of new block from total
			g_heapSentinel.size -= size;

			return pNode;
		}
	}

	return 0;
}


/**
 * Discards the specified memory object.
 * @param pMemNode			Node of the memory object
 */
void MemoryDiscard(MEM_NODE *pMemNode) {
	// validate mnode pointer
	assert(pMemNode >= g_mnodeList && pMemNode <= g_mnodeList + NUM_MNODES - 1);

	// object must be in use and locked
	assert((pMemNode->flags & (DWM_USED | DWM_LOCKED)) == DWM_USED);

	// discard it if it isn't already
	if ((pMemNode->flags & DWM_DISCARDED) == 0) {
		// free memory
		free(pMemNode->pBaseAddr);
		g_heapSentinel.size += pMemNode->size;

#ifdef DEBUG
		MemoryStats();
#endif

		// mark the node as discarded
		pMemNode->flags |= DWM_DISCARDED;
		pMemNode->pBaseAddr = NULL;
		pMemNode->size = 0;
	}
}

/**
 * Locks a memory object and returns a pointer to the first byte
 * of the objects memory block.
 * @param pMemNode			Node of the memory object
 */
void *MemoryLock(MEM_NODE *pMemNode) {
	// make sure memory object is not already locked
	assert((pMemNode->flags & DWM_LOCKED) == 0);

	// check for a discarded or null memory object
	if ((pMemNode->flags & DWM_DISCARDED) || pMemNode->size == 0)
		return NULL;

	// set the lock flag
	pMemNode->flags |= DWM_LOCKED;

#ifdef DEBUG
	MemoryStats();
#endif

	// return memory objects base address
	return pMemNode->pBaseAddr;
}

/**
 * Unlocks a memory object.
 * @param pMemNode		Node of the memory object
 */
void MemoryUnlock(MEM_NODE *pMemNode) {
	// make sure memory object is already locked
	assert(pMemNode->flags & DWM_LOCKED);

	// clear the lock flag
	pMemNode->flags &= ~DWM_LOCKED;

#ifdef DEBUG
	MemoryStats();
#endif

	// update the LRU time
	pMemNode->lruTime = DwGetCurrentTime();
}

/**
 * Changes the size of a specified memory object and re-allocate it if necessary.
 * @param pMemNode		Node of the memory object
 * @param size			New size of block
 */
void MemoryReAlloc(MEM_NODE *pMemNode, long size) {
	MEM_NODE *pNew;

	// validate mnode pointer
	assert(pMemNode >= g_mnodeList && pMemNode <= g_mnodeList + NUM_MNODES - 1);

	// align the size to machine boundary requirements
	size = (size + sizeof(void *) - 1) & ~(sizeof(void *) - 1);

	// validate the size
	assert(size);

	if (size != pMemNode->size) {
		// make sure memory object is discarded and not locked
		assert(pMemNode->flags == (DWM_USED | DWM_DISCARDED));
		assert(pMemNode->size == 0);

		// unlink the mnode from the current heap
		pMemNode->pNext->pPrev = pMemNode->pPrev;
		pMemNode->pPrev->pNext = pMemNode->pNext;

		// allocate a new node
		pNew = MemoryAlloc(size);

		// make sure memory allocated
		assert(pNew != NULL);

		// copy the node to the current node
		memcpy(pMemNode, pNew, sizeof(MEM_NODE));

		// relink the mnode into the list
		pMemNode->pPrev->pNext = pMemNode;
		pMemNode->pNext->pPrev = pMemNode;

		// free the new node
		FreeMemNode(pNew);
	}

	assert(pMemNode->pBaseAddr);
}

/**
 * Touch a memory object by updating its LRU time.
 * @param pMemNode		Node of the memory object
 */
void MemoryTouch(MEM_NODE *pMemNode) {
	// update the LRU time
	pMemNode->lruTime = DwGetCurrentTime();
}

uint8 *MemoryDeref(MEM_NODE *pMemNode) {
	return pMemNode->pBaseAddr;
}


} // End of namespace Tinsel