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1 | /* vmem.h |
2 | * | |
3 | * (c) 1999 Microsoft Corporation. All rights reserved. | |
4 | * Portions (c) 1999 ActiveState Tool Corp, http://www.ActiveState.com/ | |
5 | * | |
6 | * You may distribute under the terms of either the GNU General Public | |
7 | * License or the Artistic License, as specified in the README file. | |
8 | * | |
9 | * | |
10 | * Knuth's boundary tag algorithm Vol #1, Page 440. | |
11 | * | |
12 | * Each block in the heap has tag words before and after it, | |
13 | * TAG | |
14 | * block | |
15 | * TAG | |
16 | * The size is stored in these tags as a long word, and includes the 8 bytes | |
17 | * of overhead that the boundary tags consume. Blocks are allocated on long | |
18 | * word boundaries, so the size is always multiples of long words. When the | |
19 | * block is allocated, bit 0, (the tag bit), of the size is set to 1. When | |
20 | * a block is freed, it is merged with adjacent free blocks, and the tag bit | |
21 | * is set to 0. | |
22 | * | |
23 | * A linked list is used to manage the free list. The first two long words of | |
24 | * the block contain double links. These links are only valid when the block | |
25 | * is freed, therefore space needs to be reserved for them. Thus, the minimum | |
26 | * block size (not counting the tags) is 8 bytes. | |
27 | * | |
28 | * Since memory allocation may occur on a single threaded, explict locks are | |
29 | * provided. | |
30 | * | |
31 | */ | |
32 | ||
33 | #ifndef ___VMEM_H_INC___ | |
34 | #define ___VMEM_H_INC___ | |
35 | ||
36 | const long lAllocStart = 0x00010000; /* start at 64K */ | |
37 | const long minBlockSize = sizeof(void*)*2; | |
38 | const long sizeofTag = sizeof(long); | |
39 | const long blockOverhead = sizeofTag*2; | |
40 | const long minAllocSize = minBlockSize+blockOverhead; | |
41 | ||
42 | typedef BYTE* PBLOCK; /* pointer to a memory block */ | |
43 | ||
44 | /* | |
45 | * Macros for accessing hidden fields in a memory block: | |
46 | * | |
47 | * SIZE size of this block (tag bit 0 is 1 if block is allocated) | |
48 | * PSIZE size of previous physical block | |
49 | */ | |
50 | ||
51 | #define SIZE(block) (*(ULONG*)(((PBLOCK)(block))-sizeofTag)) | |
52 | #define PSIZE(block) (*(ULONG*)(((PBLOCK)(block))-(sizeofTag*2))) | |
53 | inline void SetTags(PBLOCK block, long size) | |
54 | { | |
55 | SIZE(block) = size; | |
56 | PSIZE(block+(size&~1)) = size; | |
57 | } | |
58 | ||
59 | /* | |
60 | * Free list pointers | |
61 | * PREV pointer to previous block | |
62 | * NEXT pointer to next block | |
63 | */ | |
64 | ||
65 | #define PREV(block) (*(PBLOCK*)(block)) | |
66 | #define NEXT(block) (*(PBLOCK*)((block)+sizeof(PBLOCK))) | |
67 | inline void SetLink(PBLOCK block, PBLOCK prev, PBLOCK next) | |
68 | { | |
69 | PREV(block) = prev; | |
70 | NEXT(block) = next; | |
71 | } | |
72 | inline void Unlink(PBLOCK p) | |
73 | { | |
74 | PBLOCK next = NEXT(p); | |
75 | PBLOCK prev = PREV(p); | |
76 | NEXT(prev) = next; | |
77 | PREV(next) = prev; | |
78 | } | |
79 | inline void AddToFreeList(PBLOCK block, PBLOCK pInList) | |
80 | { | |
81 | PBLOCK next = NEXT(pInList); | |
82 | NEXT(pInList) = block; | |
83 | SetLink(block, pInList, next); | |
84 | PREV(next) = block; | |
85 | } | |
86 | ||
87 | ||
88 | /* Macro for rounding up to the next sizeof(long) */ | |
89 | #define ROUND_UP(n) (((ULONG)(n)+sizeof(long)-1)&~(sizeof(long)-1)) | |
90 | #define ROUND_UP64K(n) (((ULONG)(n)+0x10000-1)&~(0x10000-1)) | |
91 | #define ROUND_DOWN(n) ((ULONG)(n)&~(sizeof(long)-1)) | |
92 | ||
93 | /* | |
94 | * HeapRec - a list of all non-contiguous heap areas | |
95 | * | |
96 | * Each record in this array contains information about a non-contiguous heap area. | |
97 | */ | |
98 | ||
99 | const int maxHeaps = 64; | |
100 | const long lAllocMax = 0x80000000; /* max size of allocation */ | |
101 | ||
102 | typedef struct _HeapRec | |
103 | { | |
104 | PBLOCK base; /* base of heap area */ | |
105 | ULONG len; /* size of heap area */ | |
106 | } HeapRec; | |
107 | ||
108 | ||
109 | class VMem | |
110 | { | |
111 | public: | |
112 | VMem(); | |
113 | ~VMem(); | |
114 | virtual void* Malloc(size_t size); | |
115 | virtual void* Realloc(void* pMem, size_t size); | |
116 | virtual void Free(void* pMem); | |
117 | virtual void GetLock(void); | |
118 | virtual void FreeLock(void); | |
119 | virtual int IsLocked(void); | |
120 | virtual long Release(void); | |
121 | virtual long AddRef(void); | |
122 | ||
123 | inline BOOL CreateOk(void) | |
124 | { | |
125 | return m_hHeap != NULL; | |
126 | }; | |
127 | ||
128 | void ReInit(void); | |
129 | ||
130 | protected: | |
131 | void Init(void); | |
132 | int Getmem(size_t size); | |
133 | int HeapAdd(void* ptr, size_t size); | |
134 | void* Expand(void* block, size_t size); | |
135 | void WalkHeap(void); | |
136 | ||
137 | HANDLE m_hHeap; // memory heap for this script | |
138 | char m_FreeDummy[minAllocSize]; // dummy free block | |
139 | PBLOCK m_pFreeList; // pointer to first block on free list | |
140 | PBLOCK m_pRover; // roving pointer into the free list | |
141 | HeapRec m_heaps[maxHeaps]; // list of all non-contiguous heap areas | |
142 | int m_nHeaps; // no. of heaps in m_heaps | |
143 | long m_lAllocSize; // current alloc size | |
144 | long m_lRefCount; // number of current users | |
145 | CRITICAL_SECTION m_cs; // access lock | |
146 | }; | |
147 | ||
148 | // #define _DEBUG_MEM | |
149 | #ifdef _DEBUG_MEM | |
150 | #define ASSERT(f) if(!(f)) DebugBreak(); | |
151 | ||
152 | inline void MEMODS(char *str) | |
153 | { | |
154 | OutputDebugString(str); | |
155 | OutputDebugString("\n"); | |
156 | } | |
157 | ||
158 | inline void MEMODSlx(char *str, long x) | |
159 | { | |
160 | char szBuffer[512]; | |
161 | sprintf(szBuffer, "%s %lx\n", str, x); | |
162 | OutputDebugString(szBuffer); | |
163 | } | |
164 | ||
165 | #define WALKHEAP() WalkHeap() | |
166 | #define WALKHEAPTRACE() m_pRover = NULL; WalkHeap() | |
167 | ||
168 | #else | |
169 | ||
170 | #define ASSERT(f) | |
171 | #define MEMODS(x) | |
172 | #define MEMODSlx(x, y) | |
173 | #define WALKHEAP() | |
174 | #define WALKHEAPTRACE() | |
175 | ||
176 | #endif | |
177 | ||
178 | ||
179 | VMem::VMem() | |
180 | { | |
181 | m_lRefCount = 1; | |
182 | BOOL bRet = (NULL != (m_hHeap = HeapCreate(HEAP_NO_SERIALIZE, | |
183 | lAllocStart, /* initial size of heap */ | |
184 | 0))); /* no upper limit on size of heap */ | |
185 | ASSERT(bRet); | |
186 | ||
187 | InitializeCriticalSection(&m_cs); | |
188 | ||
189 | Init(); | |
190 | } | |
191 | ||
192 | VMem::~VMem(void) | |
193 | { | |
194 | ASSERT(HeapValidate(m_hHeap, HEAP_NO_SERIALIZE, NULL)); | |
195 | WALKHEAPTRACE(); | |
196 | DeleteCriticalSection(&m_cs); | |
197 | BOOL bRet = HeapDestroy(m_hHeap); | |
198 | ASSERT(bRet); | |
199 | } | |
200 | ||
201 | void VMem::ReInit(void) | |
202 | { | |
203 | for(int index = 0; index < m_nHeaps; ++index) | |
204 | HeapFree(m_hHeap, HEAP_NO_SERIALIZE, m_heaps[index].base); | |
205 | ||
206 | Init(); | |
207 | } | |
208 | ||
209 | void VMem::Init(void) | |
210 | { /* | |
211 | * Initialize the free list by placing a dummy zero-length block on it. | |
212 | * Set the number of non-contiguous heaps to zero. | |
213 | */ | |
214 | m_pFreeList = m_pRover = (PBLOCK)(&m_FreeDummy[minBlockSize]); | |
215 | PSIZE(m_pFreeList) = SIZE(m_pFreeList) = 0; | |
216 | PREV(m_pFreeList) = NEXT(m_pFreeList) = m_pFreeList; | |
217 | ||
218 | m_nHeaps = 0; | |
219 | m_lAllocSize = lAllocStart; | |
220 | } | |
221 | ||
222 | void* VMem::Malloc(size_t size) | |
223 | { | |
224 | WALKHEAP(); | |
225 | ||
226 | /* | |
227 | * Adjust the real size of the block to be a multiple of sizeof(long), and add | |
228 | * the overhead for the boundary tags. Disallow negative or zero sizes. | |
229 | */ | |
230 | size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize; | |
231 | if((int)realsize < minAllocSize || size == 0) | |
232 | return NULL; | |
233 | ||
234 | /* | |
235 | * Start searching the free list at the rover. If we arrive back at rover without | |
236 | * finding anything, allocate some memory from the heap and try again. | |
237 | */ | |
238 | PBLOCK ptr = m_pRover; /* start searching at rover */ | |
239 | int loops = 2; /* allow two times through the loop */ | |
240 | for(;;) { | |
241 | size_t lsize = SIZE(ptr); | |
242 | ASSERT((lsize&1)==0); | |
243 | /* is block big enough? */ | |
244 | if(lsize >= realsize) { | |
245 | /* if the remainder is too small, don't bother splitting the block. */ | |
246 | size_t rem = lsize - realsize; | |
247 | if(rem < minAllocSize) { | |
248 | if(m_pRover == ptr) | |
249 | m_pRover = NEXT(ptr); | |
250 | ||
251 | /* Unlink the block from the free list. */ | |
252 | Unlink(ptr); | |
253 | } | |
254 | else { | |
255 | /* | |
256 | * split the block | |
257 | * The remainder is big enough to split off into a new block. | |
258 | * Use the end of the block, resize the beginning of the block | |
259 | * no need to change the free list. | |
260 | */ | |
261 | SetTags(ptr, rem); | |
262 | ptr += SIZE(ptr); | |
263 | lsize = realsize; | |
264 | } | |
265 | /* Set the boundary tags to mark it as allocated. */ | |
266 | SetTags(ptr, lsize | 1); | |
267 | return ((void *)ptr); | |
268 | } | |
269 | ||
270 | /* | |
271 | * This block was unsuitable. If we've gone through this list once already without | |
272 | * finding anything, allocate some new memory from the heap and try again. | |
273 | */ | |
274 | ptr = NEXT(ptr); | |
275 | if(ptr == m_pRover) { | |
276 | if(!(loops-- && Getmem(realsize))) { | |
277 | return NULL; | |
278 | } | |
279 | ptr = m_pRover; | |
280 | } | |
281 | } | |
282 | } | |
283 | ||
284 | void* VMem::Realloc(void* block, size_t size) | |
285 | { | |
286 | WALKHEAP(); | |
287 | ||
288 | /* if size is zero, free the block. */ | |
289 | if(size == 0) { | |
290 | Free(block); | |
291 | return (NULL); | |
292 | } | |
293 | ||
294 | /* if block pointer is NULL, do a Malloc(). */ | |
295 | if(block == NULL) | |
296 | return Malloc(size); | |
297 | ||
298 | /* | |
299 | * Grow or shrink the block in place. | |
300 | * if the block grows then the next block will be used if free | |
301 | */ | |
302 | if(Expand(block, size) != NULL) | |
303 | return block; | |
304 | ||
305 | /* | |
306 | * adjust the real size of the block to be a multiple of sizeof(long), and add the | |
307 | * overhead for the boundary tags. Disallow negative or zero sizes. | |
308 | */ | |
309 | size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize; | |
310 | if((int)realsize < minAllocSize) | |
311 | return NULL; | |
312 | ||
313 | /* | |
314 | * see if the previous block is free, and is it big enough to cover the new size | |
315 | * if merged with the current block. | |
316 | */ | |
317 | PBLOCK ptr = (PBLOCK)block; | |
318 | size_t cursize = SIZE(ptr) & ~1; | |
319 | size_t psize = PSIZE(ptr); | |
320 | if((psize&1) == 0 && (psize + cursize) >= realsize) { | |
321 | PBLOCK prev = ptr - psize; | |
322 | if(m_pRover == prev) | |
323 | m_pRover = NEXT(prev); | |
324 | ||
325 | /* Unlink the next block from the free list. */ | |
326 | Unlink(prev); | |
327 | ||
328 | /* Copy contents of old block to new location, make it the current block. */ | |
329 | memmove(prev, ptr, cursize); | |
330 | cursize += psize; /* combine sizes */ | |
331 | ptr = prev; | |
332 | ||
333 | size_t rem = cursize - realsize; | |
334 | if(rem >= minAllocSize) { | |
335 | /* | |
336 | * The remainder is big enough to be a new block. Set boundary | |
337 | * tags for the resized block and the new block. | |
338 | */ | |
339 | prev = ptr + realsize; | |
340 | /* | |
341 | * add the new block to the free list. | |
342 | * next block cannot be free | |
343 | */ | |
344 | SetTags(prev, rem); | |
345 | AddToFreeList(prev, m_pFreeList); | |
346 | cursize = realsize; | |
347 | } | |
348 | /* Set the boundary tags to mark it as allocated. */ | |
349 | SetTags(ptr, cursize | 1); | |
350 | return ((void *)ptr); | |
351 | } | |
352 | ||
353 | /* Allocate a new block, copy the old to the new, and free the old. */ | |
354 | if((ptr = (PBLOCK)Malloc(size)) != NULL) { | |
355 | memmove(ptr, block, cursize-minBlockSize); | |
356 | Free(block); | |
357 | } | |
358 | return ((void *)ptr); | |
359 | } | |
360 | ||
361 | void VMem::Free(void* p) | |
362 | { | |
363 | WALKHEAP(); | |
364 | ||
365 | /* Ignore null pointer. */ | |
366 | if(p == NULL) | |
367 | return; | |
368 | ||
369 | PBLOCK ptr = (PBLOCK)p; | |
370 | ||
371 | /* Check for attempt to free a block that's already free. */ | |
372 | size_t size = SIZE(ptr); | |
373 | if((size&1) == 0) { | |
374 | MEMODSlx("Attempt to free previously freed block", (long)p); | |
375 | return; | |
376 | } | |
377 | size &= ~1; /* remove allocated tag */ | |
378 | ||
379 | /* if previous block is free, add this block to it. */ | |
380 | int linked = FALSE; | |
381 | size_t psize = PSIZE(ptr); | |
382 | if((psize&1) == 0) { | |
383 | ptr -= psize; /* point to previous block */ | |
384 | size += psize; /* merge the sizes of the two blocks */ | |
385 | linked = TRUE; /* it's already on the free list */ | |
386 | } | |
387 | ||
388 | /* if the next physical block is free, merge it with this block. */ | |
389 | PBLOCK next = ptr + size; /* point to next physical block */ | |
390 | size_t nsize = SIZE(next); | |
391 | if((nsize&1) == 0) { | |
392 | /* block is free move rover if needed */ | |
393 | if(m_pRover == next) | |
394 | m_pRover = NEXT(next); | |
395 | ||
396 | /* unlink the next block from the free list. */ | |
397 | Unlink(next); | |
398 | ||
399 | /* merge the sizes of this block and the next block. */ | |
400 | size += nsize; | |
401 | } | |
402 | ||
403 | /* Set the boundary tags for the block; */ | |
404 | SetTags(ptr, size); | |
405 | ||
406 | /* Link the block to the head of the free list. */ | |
407 | if(!linked) { | |
408 | AddToFreeList(ptr, m_pFreeList); | |
409 | } | |
410 | } | |
411 | ||
412 | void VMem::GetLock(void) | |
413 | { | |
414 | EnterCriticalSection(&m_cs); | |
415 | } | |
416 | ||
417 | void VMem::FreeLock(void) | |
418 | { | |
419 | LeaveCriticalSection(&m_cs); | |
420 | } | |
421 | ||
422 | int VMem::IsLocked(void) | |
423 | { | |
90430aa1 GS |
424 | #if 0 |
425 | /* XXX TryEnterCriticalSection() is not available in some versions | |
426 | * of Windows 95. Since this code is not used anywhere yet, we | |
427 | * skirt the issue for now. */ | |
7766f137 GS |
428 | BOOL bAccessed = TryEnterCriticalSection(&m_cs); |
429 | if(bAccessed) { | |
430 | LeaveCriticalSection(&m_cs); | |
431 | } | |
432 | return !bAccessed; | |
90430aa1 GS |
433 | #else |
434 | ASSERT(0); /* alarm bells for when somebody calls this */ | |
435 | return 0; | |
436 | #endif | |
7766f137 GS |
437 | } |
438 | ||
439 | ||
440 | long VMem::Release(void) | |
441 | { | |
442 | long lCount = InterlockedDecrement(&m_lRefCount); | |
443 | if(!lCount) | |
444 | delete this; | |
445 | return lCount; | |
446 | } | |
447 | ||
448 | long VMem::AddRef(void) | |
449 | { | |
450 | long lCount = InterlockedIncrement(&m_lRefCount); | |
451 | return lCount; | |
452 | } | |
453 | ||
454 | ||
455 | int VMem::Getmem(size_t requestSize) | |
456 | { /* returns -1 is successful 0 if not */ | |
457 | void *ptr; | |
458 | ||
459 | /* Round up size to next multiple of 64K. */ | |
460 | size_t size = (size_t)ROUND_UP64K(requestSize); | |
461 | ||
462 | /* | |
463 | * if the size requested is smaller than our current allocation size | |
464 | * adjust up | |
465 | */ | |
466 | if(size < (unsigned long)m_lAllocSize) | |
467 | size = m_lAllocSize; | |
468 | ||
469 | /* Update the size to allocate on the next request */ | |
470 | if(m_lAllocSize != lAllocMax) | |
471 | m_lAllocSize <<= 1; | |
472 | ||
473 | if(m_nHeaps != 0) { | |
474 | /* Expand the last allocated heap */ | |
475 | ptr = HeapReAlloc(m_hHeap, HEAP_REALLOC_IN_PLACE_ONLY|HEAP_ZERO_MEMORY|HEAP_NO_SERIALIZE, | |
476 | m_heaps[m_nHeaps-1].base, | |
477 | m_heaps[m_nHeaps-1].len + size); | |
478 | if(ptr != 0) { | |
479 | HeapAdd(((char*)ptr) + m_heaps[m_nHeaps-1].len, size); | |
480 | return -1; | |
481 | } | |
482 | } | |
483 | ||
484 | /* | |
485 | * if we didn't expand a block to cover the requested size | |
486 | * allocate a new Heap | |
487 | * the size of this block must include the additional dummy tags at either end | |
488 | * the above ROUND_UP64K may not have added any memory to include this. | |
489 | */ | |
490 | if(size == requestSize) | |
491 | size = (size_t)ROUND_UP64K(requestSize+(sizeofTag*2)); | |
492 | ||
493 | ptr = HeapAlloc(m_hHeap, HEAP_ZERO_MEMORY|HEAP_NO_SERIALIZE, size); | |
494 | if(ptr == 0) { | |
495 | MEMODSlx("HeapAlloc failed on size!!!", size); | |
496 | return 0; | |
497 | } | |
498 | ||
499 | HeapAdd(ptr, size); | |
500 | return -1; | |
501 | } | |
502 | ||
503 | int VMem::HeapAdd(void *p, size_t size) | |
504 | { /* if the block can be succesfully added to the heap, returns 0; otherwise -1. */ | |
505 | int index; | |
506 | ||
507 | /* Check size, then round size down to next long word boundary. */ | |
508 | if(size < minAllocSize) | |
509 | return -1; | |
510 | ||
511 | size = (size_t)ROUND_DOWN(size); | |
512 | PBLOCK ptr = (PBLOCK)p; | |
513 | ||
514 | /* | |
515 | * Search for another heap area that's contiguous with the bottom of this new area. | |
516 | * (It should be extremely unusual to find one that's contiguous with the top). | |
517 | */ | |
518 | for(index = 0; index < m_nHeaps; ++index) { | |
519 | if(ptr == m_heaps[index].base + (int)m_heaps[index].len) { | |
520 | /* | |
521 | * The new block is contiguous with a previously allocated heap area. Add its | |
522 | * length to that of the previous heap. Merge it with the the dummy end-of-heap | |
523 | * area marker of the previous heap. | |
524 | */ | |
525 | m_heaps[index].len += size; | |
526 | break; | |
527 | } | |
528 | } | |
529 | ||
530 | if(index == m_nHeaps) { | |
531 | /* The new block is not contiguous. Add it to the heap list. */ | |
532 | if(m_nHeaps == maxHeaps) { | |
533 | return -1; /* too many non-contiguous heaps */ | |
534 | } | |
535 | m_heaps[m_nHeaps].base = ptr; | |
536 | m_heaps[m_nHeaps].len = size; | |
537 | m_nHeaps++; | |
538 | ||
539 | /* | |
540 | * Reserve the first LONG in the block for the ending boundary tag of a dummy | |
541 | * block at the start of the heap area. | |
542 | */ | |
543 | size -= minBlockSize; | |
544 | ptr += minBlockSize; | |
545 | PSIZE(ptr) = 1; /* mark the dummy previous block as allocated */ | |
546 | } | |
547 | ||
548 | /* | |
549 | * Convert the heap to one large block. Set up its boundary tags, and those of | |
550 | * marker block after it. The marker block before the heap will already have | |
551 | * been set up if this heap is not contiguous with the end of another heap. | |
552 | */ | |
553 | SetTags(ptr, size | 1); | |
554 | PBLOCK next = ptr + size; /* point to dummy end block */ | |
555 | SIZE(next) = 1; /* mark the dummy end block as allocated */ | |
556 | ||
557 | /* | |
558 | * Link the block to the start of the free list by calling free(). | |
559 | * This will merge the block with any adjacent free blocks. | |
560 | */ | |
561 | Free(ptr); | |
562 | return 0; | |
563 | } | |
564 | ||
565 | ||
566 | void* VMem::Expand(void* block, size_t size) | |
567 | { | |
568 | /* | |
569 | * Adjust the size of the block to be a multiple of sizeof(long), and add the | |
570 | * overhead for the boundary tags. Disallow negative or zero sizes. | |
571 | */ | |
572 | size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize; | |
573 | if((int)realsize < minAllocSize || size == 0) | |
574 | return NULL; | |
575 | ||
576 | PBLOCK ptr = (PBLOCK)block; | |
577 | ||
578 | /* if the current size is the same as requested, do nothing. */ | |
579 | size_t cursize = SIZE(ptr) & ~1; | |
580 | if(cursize == realsize) { | |
581 | return block; | |
582 | } | |
583 | ||
584 | /* if the block is being shrunk, convert the remainder of the block into a new free block. */ | |
585 | if(realsize <= cursize) { | |
586 | size_t nextsize = cursize - realsize; /* size of new remainder block */ | |
587 | if(nextsize >= minAllocSize) { | |
588 | /* | |
589 | * Split the block | |
590 | * Set boundary tags for the resized block and the new block. | |
591 | */ | |
592 | SetTags(ptr, realsize | 1); | |
593 | ptr += realsize; | |
594 | ||
595 | /* | |
596 | * add the new block to the free list. | |
597 | * call Free to merge this block with next block if free | |
598 | */ | |
599 | SetTags(ptr, nextsize | 1); | |
600 | Free(ptr); | |
601 | } | |
602 | ||
603 | return block; | |
604 | } | |
605 | ||
606 | PBLOCK next = ptr + cursize; | |
607 | size_t nextsize = SIZE(next); | |
608 | ||
609 | /* Check the next block for consistency.*/ | |
610 | if((nextsize&1) == 0 && (nextsize + cursize) >= realsize) { | |
611 | /* | |
612 | * The next block is free and big enough. Add the part that's needed | |
613 | * to our block, and split the remainder off into a new block. | |
614 | */ | |
615 | if(m_pRover == next) | |
616 | m_pRover = NEXT(next); | |
617 | ||
618 | /* Unlink the next block from the free list. */ | |
619 | Unlink(next); | |
620 | cursize += nextsize; /* combine sizes */ | |
621 | ||
622 | size_t rem = cursize - realsize; /* size of remainder */ | |
623 | if(rem >= minAllocSize) { | |
624 | /* | |
625 | * The remainder is big enough to be a new block. | |
626 | * Set boundary tags for the resized block and the new block. | |
627 | */ | |
628 | next = ptr + realsize; | |
629 | /* | |
630 | * add the new block to the free list. | |
631 | * next block cannot be free | |
632 | */ | |
633 | SetTags(next, rem); | |
634 | AddToFreeList(next, m_pFreeList); | |
635 | cursize = realsize; | |
636 | } | |
637 | /* Set the boundary tags to mark it as allocated. */ | |
638 | SetTags(ptr, cursize | 1); | |
639 | return ((void *)ptr); | |
640 | } | |
641 | return NULL; | |
642 | } | |
643 | ||
644 | #ifdef _DEBUG_MEM | |
645 | #define LOG_FILENAME "P:\\Apps\\Perl\\Result.txt" | |
646 | ||
647 | void MemoryUsageMessage(char *str, long x, long y, int c) | |
648 | { | |
649 | static FILE* fp = NULL; | |
650 | char szBuffer[512]; | |
651 | if(str) { | |
652 | if(!fp) | |
653 | fp = fopen(LOG_FILENAME, "w"); | |
654 | sprintf(szBuffer, str, x, y, c); | |
655 | fputs(szBuffer, fp); | |
656 | } | |
657 | else { | |
658 | fflush(fp); | |
659 | fclose(fp); | |
660 | } | |
661 | } | |
662 | ||
663 | void VMem::WalkHeap(void) | |
664 | { | |
665 | if(!m_pRover) { | |
666 | MemoryUsageMessage("VMem heaps used %d\n", m_nHeaps, 0, 0); | |
667 | } | |
668 | ||
669 | /* Walk all the heaps - verify structures */ | |
670 | for(int index = 0; index < m_nHeaps; ++index) { | |
671 | PBLOCK ptr = m_heaps[index].base; | |
672 | size_t size = m_heaps[index].len; | |
673 | ASSERT(HeapValidate(m_hHeap, HEAP_NO_SERIALIZE, p)); | |
674 | ||
675 | /* set over reserved header block */ | |
676 | size -= minBlockSize; | |
677 | ptr += minBlockSize; | |
678 | PBLOCK pLast = ptr + size; | |
679 | ASSERT(PSIZE(ptr) == 1); /* dummy previous block is allocated */ | |
680 | ASSERT(SIZE(pLast) == 1); /* dummy next block is allocated */ | |
681 | while(ptr < pLast) { | |
682 | ASSERT(ptr > m_heaps[index].base); | |
683 | size_t cursize = SIZE(ptr) & ~1; | |
684 | ASSERT((PSIZE(ptr+cursize) & ~1) == cursize); | |
685 | if(!m_pRover) { | |
686 | MemoryUsageMessage("Memory Block %08x: Size %08x %c\n", (long)ptr, cursize, (SIZE(p)&1) ? 'x' : ' '); | |
687 | } | |
688 | if(!(SIZE(ptr)&1)) { | |
689 | /* this block is on the free list */ | |
690 | PBLOCK tmp = NEXT(ptr); | |
691 | while(tmp != ptr) { | |
692 | ASSERT((SIZE(tmp)&1)==0); | |
693 | if(tmp == m_pFreeList) | |
694 | break; | |
695 | ASSERT(NEXT(tmp)); | |
696 | tmp = NEXT(tmp); | |
697 | } | |
698 | if(tmp == ptr) { | |
699 | MemoryUsageMessage("Memory Block %08x: Size %08x free but not in free list\n", (long)ptr, cursize, 0); | |
700 | } | |
701 | } | |
702 | ptr += cursize; | |
703 | } | |
704 | } | |
705 | if(!m_pRover) { | |
706 | MemoryUsageMessage(NULL, 0, 0, 0); | |
707 | } | |
708 | } | |
709 | #endif | |
710 | ||
711 | #endif /* ___VMEM_H_INC___ */ |