heapsimple.cpp@ 329

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1	/* $Id: heapsimple.cpp 329 2007-01-25 19:56:10Z vboxsync $ */
2	/** @file
3	* InnoTek Portable Runtime - A Simple Heap.
4	*/
5
6	/*
7	* Copyright (C) 2006 InnoTek Systemberatung GmbH
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License as published by the Free Software Foundation,
13	* in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
14	* distribution. VirtualBox OSE is distributed in the hope that it will
15	* be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* If you received this file as part of a commercial VirtualBox
18	* distribution, then only the terms of your commercial VirtualBox
19	* license agreement apply instead of the previous paragraph.
20	*/
21
22
23	/*******************************************************************************
24	* Header Files *
25	*******************************************************************************/
26	#define LOG_GROUP RTLOGGROUP_DEFAULT
27	#include <iprt/heap.h>
28	#include <iprt/assert.h>
29	#include <iprt/asm.h>
30	#include <iprt/string.h>
31	#include <iprt/err.h>
32	#include <iprt/log.h>
33	#include <iprt/param.h>
34
35
36	/*******************************************************************************
37	* Structures and Typedefs *
38	*******************************************************************************/
39	/** Pointer to the heap anchor block. */
40	typedef struct RTHEAPSIMPLEINTERNAL *PRTHEAPSIMPLEINTERNAL;
41	/** Pointer to a heap block. */
42	typedef struct RTHEAPSIMPLEBLOCK *PRTHEAPSIMPLEBLOCK;
43	/** Pointer to a free heap block. */
44	typedef struct RTHEAPSIMPLEFREE *PRTHEAPSIMPLEFREE;
45
46	/**
47	* Structure describing a simple heap block.
48	* If this block is allocated, it is followed by the user user data.
49	* If this block is free, see RTHEAPSIMPLEFREE.
50	*/
51	typedef struct RTHEAPSIMPLEBLOCK
52	{
53	/** The next block in the global block list. */
54	PRTHEAPSIMPLEBLOCK pNext;
55	/** The previous block in the global block list. */
56	PRTHEAPSIMPLEBLOCK pPrev;
57	/** Pointer to the heap anchor block. */
58	PRTHEAPSIMPLEINTERNAL pHeap;
59	/** Flags + magic. */
60	uintptr_t fFlags;
61	} RTHEAPSIMPLEBLOCK;
62	AssertCompileSizeAlignment(RTHEAPSIMPLEBLOCK, 16);
63
64	/** The block is free if this flag is set. When cleared it's allocated. */
65	#define RTHEAPSIMPLEBLOCK_FLAGS_FREE ((uintptr_t)BIT(0))
66	/** The magic value. */
67	#define RTHEAPSIMPLEBLOCK_FLAGS_MAGIC ((uintptr_t)0xabcdef00)
68	/** The mask that needs to be applied to RTHEAPSIMPLEBLOCK::fFalgs to obtain the magic value. */
69	#define RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK (~(uintptr_t)BIT(0))
70
71	/**
72	* Checks if the specified block is valid or not.
73	* @returns boolean answer.
74	* @param pBlock Pointer to a RTHEAPSIMPLEBLOCK structure.
75	*/
76	#define RTHEAPSIMPLEBLOCK_IS_VALID(pBlock) \
77	( ((pBlock)->fFlags & RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK) == RTHEAPSIMPLEBLOCK_FLAGS_MAGIC )
78
79	/**
80	* Checks if the specified block is valid and in use.
81	* @returns boolean answer.
82	* @param pBlock Pointer to a RTHEAPSIMPLEBLOCK structure.
83	*/
84	#define RTHEAPSIMPLEBLOCK_IS_VALID_USED(pBlock) \
85	( ((pBlock)->fFlags & (RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK \| RTHEAPSIMPLEBLOCK_FLAGS_FREE)) \
86	== RTHEAPSIMPLEBLOCK_FLAGS_MAGIC )
87
88	/**
89	* Checks if the specified block is valid and free.
90	* @returns boolean answer.
91	* @param pBlock Pointer to a RTHEAPSIMPLEBLOCK structure.
92	*/
93	#define RTHEAPSIMPLEBLOCK_IS_VALID_FREE(pBlock) \
94	( ((pBlock)->fFlags & (RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK \| RTHEAPSIMPLEBLOCK_FLAGS_FREE)) \
95	== (RTHEAPSIMPLEBLOCK_FLAGS_MAGIC \| RTHEAPSIMPLEBLOCK_FLAGS_FREE) )
96
97	/**
98	* Checks if the specified block is free or not.
99	* @returns boolean answer.
100	* @param pBlock Pointer to a valid RTHEAPSIMPLEBLOCK structure.
101	*/
102	#define RTHEAPSIMPLEBLOCK_IS_FREE(pBlock) (!!((pBlock)->fFlags & RTHEAPSIMPLEBLOCK_FLAGS_FREE))
103
104	/**
105	* A free heap block.
106	* This is an extended version of RTHEAPSIMPLEBLOCK that takes the unused
107	* user data to store free list pointers and a cached size value.
108	*/
109	typedef struct RTHEAPSIMPLEFREE
110	{
111	/** Core stuff. */
112	RTHEAPSIMPLEBLOCK Core;
113	/** Pointer to the next free block. */
114	PRTHEAPSIMPLEFREE pNext;
115	/** Pointer to the previous free block. */
116	PRTHEAPSIMPLEFREE pPrev;
117	/** The size of the block (excluding the RTHEAPSIMPLEBLOCK part). */
118	size_t cb;
119	/** An alignment filler to make it a multiple of (sizeof(void ) 2). */
120	size_t Alignment;
121	} RTHEAPSIMPLEFREE;
122
123
124	/**
125	* The heap anchor block.
126	* This structure is placed at the head of the memory block specified to RTHeapSimpleInit(),
127	* which means that the first RTHEAPSIMPLEBLOCK appears immediately after this structure.
128	*/
129	typedef struct RTHEAPSIMPLEINTERNAL
130	{
131	/** The typical magic (RTHEAPSIMPLE_MAGIC). */
132	size_t uMagic;
133	/** The heap size. (This structure is not included!) */
134	size_t cbHeap;
135	/** Pointer to the end of the heap. */
136	void *pvEnd;
137	/** The amount of free memory in the heap. */
138	size_t cbFree;
139	/** Free head pointer. */
140	PRTHEAPSIMPLEFREE pFreeHead;
141	/** Free tail pointer. */
142	PRTHEAPSIMPLEFREE pFreeTail;
143	/** Make the size of this structure is a multiple of 32. */
144	size_t auAlignment[2];
145	} RTHEAPSIMPLEINTERNAL;
146	AssertCompileSizeAlignment(RTHEAPSIMPLEINTERNAL, 32);
147
148	/** Magic number for RTHEAPSIMPLEINTERNAL::u32Magic. (Kyoichi Katayama) */
149	#define RTHEAPSIMPLE_MAGIC 0x19590105
150
151
152	/** The minimum allocation size. */
153	#define RTHEAPSIMPLE_MIN_BLOCK (sizeof(RTHEAPSIMPLEBLOCK))
154	AssertCompile(RTHEAPSIMPLE_MIN_BLOCK >= sizeof(RTHEAPSIMPLEBLOCK));
155	AssertCompile(RTHEAPSIMPLE_MIN_BLOCK >= sizeof(RTHEAPSIMPLEFREE) - sizeof(RTHEAPSIMPLEBLOCK));
156
157	/** The minimum and default alignment. */
158	#define RTHEAPSIMPLE_ALIGNMENT (sizeof(RTHEAPSIMPLEBLOCK))
159
160
161	/*******************************************************************************
162	* Defined Constants And Macros *
163	*******************************************************************************/
164	#ifdef RT_STRICT
165	# define RTHEAPSIMPLE_STRICT 1
166	#endif
167
168	#define ASSERT_L(a, b) AssertMsg((uintptr_t)(a) < (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
169	#define ASSERT_LE(a, b) AssertMsg((uintptr_t)(a) <= (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
170	#define ASSERT_G(a, b) AssertMsg((uintptr_t)(a) > (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
171	#define ASSERT_GE(a, b) AssertMsg((uintptr_t)(a) >= (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
172	#define ASSERT_ALIGN(a) AssertMsg(!((uintptr_t)(a) & (RTHEAPSIMPLE_ALIGNMENT - 1)), ("a=%p\n", (uintptr_t)(a)))
173
174	#define ASSERT_PREV(pHeapInt, pBlock) \
175	do { ASSERT_ALIGN((pBlock)->pPrev); \
176	if ((pBlock)->pPrev) \
177	{ \
178	ASSERT_L((pBlock)->pPrev, (pBlock)); \
179	ASSERT_GE((pBlock)->pPrev, (pHeapInt) + 1); \
180	} \
181	else \
182	Assert((pBlock) == (PRTHEAPSIMPLEBLOCK)((pHeapInt) + 1)); \
183	} while (0)
184
185	#define ASSERT_NEXT(pHeap, pBlock) \
186	do { ASSERT_ALIGN((pBlock)->pNext); \
187	if ((pBlock)->pNext) \
188	{ \
189	ASSERT_L((pBlock)->pNext, (pHeapInt)->pvEnd); \
190	ASSERT_G((pBlock)->pNext, (pBlock)); \
191	} \
192	} while (0)
193
194	#define ASSERT_BLOCK(pHeapInt, pBlock) \
195	do { AssertMsg(RTHEAPSIMPLEBLOCK_IS_VALID(pBlock), ("%#x\n", (pBlock)->fFlags)); \
196	AssertMsg((pBlock)->pHeap == (pHeapInt), ("%p != %p\n", (pBlock)->pHeap, (pHeapInt))); \
197	ASSERT_GE((pBlock), (pHeapInt) + 1); \
198	ASSERT_L((pBlock), (pHeapInt)->pvEnd); \
199	ASSERT_NEXT(pHeapInt, pBlock); \
200	ASSERT_PREV(pHeapInt, pBlock); \
201	} while (0)
202
203	#define ASSERT_BLOCK_USED(pHeapInt, pBlock) \
204	do { AssertMsg(RTHEAPSIMPLEBLOCK_IS_VALID_USED((pBlock)), ("%#x\n", (pBlock)->fFlags)); \
205	AssertMsg((pBlock)->pHeap == (pHeapInt), ("%p != %p\n", (pBlock)->pHeap, (pHeapInt))); \
206	ASSERT_GE((pBlock), (pHeapInt) + 1); \
207	ASSERT_L((pBlock), (pHeapInt)->pvEnd); \
208	ASSERT_NEXT(pHeapInt, pBlock); \
209	ASSERT_PREV(pHeapInt, pBlock); \
210	} while (0)
211
212	#define ASSERT_FREE_PREV(pHeapInt, pBlock) \
213	do { ASSERT_ALIGN((pBlock)->pPrev); \
214	if ((pBlock)->pPrev) \
215	{ \
216	ASSERT_GE((pBlock)->pPrev, (pHeapInt)->pFreeHead); \
217	ASSERT_L((pBlock)->pPrev, (pBlock)); \
218	ASSERT_LE((pBlock)->pPrev, (pBlock)->Core.pPrev); \
219	} \
220	else \
221	Assert((pBlock) == (pHeapInt)->pFreeHead); \
222	} while (0)
223
224	#define ASSERT_FREE_NEXT(pHeapInt, pBlock) \
225	do { ASSERT_ALIGN((pBlock)->pNext); \
226	if ((pBlock)->pNext) \
227	{ \
228	ASSERT_LE((pBlock)->pNext, (pHeapInt)->pFreeTail); \
229	ASSERT_G((pBlock)->pNext, (pBlock)); \
230	ASSERT_GE((pBlock)->pNext, (pBlock)->Core.pNext); \
231	} \
232	else \
233	Assert((pBlock) == (pHeapInt)->pFreeTail); \
234	} while (0)
235
236	#ifdef RTHEAPSIMPLE_STRICT
237	# define ASSERT_FREE_CB(pHeapInt, pBlock) \
238	do { size_t cbCalc = ((pBlock)->Core.pNext ? (uintptr_t)(pBlock)->Core.pNext : (uintptr_t)(pHeapInt)->pvEnd) \
239	- (uintptr_t)(pBlock) - sizeof(RTHEAPSIMPLEBLOCK); \
240	AssertMsg((pBlock)->cb == cbCalc, ("cb=%#zx cbCalc=%#zx\n", (pBlock)->cb, cbCalc)); \
241	} while (0)
242	#else
243	# define ASSERT_FREE_CB(pHeapInt, pBlock) do {} while (0)
244	#endif
245
246	/** Asserts that a free block is valid. */
247	#define ASSERT_BLOCK_FREE(pHeapInt, pBlock) \
248	do { ASSERT_BLOCK(pHeapInt, &(pBlock)->Core); \
249	Assert(RTHEAPSIMPLEBLOCK_IS_VALID_FREE(&(pBlock)->Core)); \
250	ASSERT_GE((pBlock), (pHeapInt)->pFreeHead); \
251	ASSERT_LE((pBlock), (pHeapInt)->pFreeTail); \
252	ASSERT_FREE_NEXT(pHeapInt, pBlock); \
253	ASSERT_FREE_PREV(pHeapInt, pBlock); \
254	ASSERT_FREE_CB(pHeapInt, pBlock); \
255	} while (0)
256
257	/** Asserts that the heap anchor block is ok. */
258	#define ASSERT_ANCHOR(pHeapInt) \
259	do { AssertPtr(pHeapInt);\
260	Assert((pHeapInt)->uMagic == RTHEAPSIMPLE_MAGIC); \
261	} while (0)
262
263
264	/*******************************************************************************
265	* Internal Functions *
266	*******************************************************************************/
267	#ifdef RTHEAPSIMPLE_STRICT
268	static void rtHeapSimpleAssertAll(PRTHEAPSIMPLEINTERNAL pHeapInt);
269	#endif
270	static PRTHEAPSIMPLEBLOCK rtHeapSimpleAllocBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, size_t cb, size_t uAlignment);
271	static void rtHeapSimpleFreeBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, PRTHEAPSIMPLEBLOCK pBlock);
272
273
274	/**
275	* Initializes the heap.
276	*
277	* @returns IPRT status code on success.
278	* @param pHeap Where to store the heap anchor block on success.
279	* @param pvMemory Pointer to the heap memory.
280	* @param cbMemory The size of the heap memory.
281	*/
282	RTDECL(int) RTHeapSimpleInit(PRTHEAPSIMPLE pHeap, void *pvMemory, size_t cbMemory)
283	{
284	/*
285	* Validate input. The imposed minimum heap size is just a convenien value.
286	*/
287	AssertReturn(cbMemory >= PAGE_SIZE, VERR_INVALID_PARAMETER);
288	AssertPtrReturn(pvMemory, VERR_INVALID_POINTER);
289	AssertReturn((uintptr_t)pvMemory + (cbMemory - 1) > (uintptr_t)cbMemory, VERR_INVALID_PARAMETER);
290
291	/*
292	* Place the heap anchor block at the start of the heap memory,
293	* enforce 32 byte alignment of it. Also align the heap size correctly.
294	*/
295	PRTHEAPSIMPLEINTERNAL pHeapInt = (PRTHEAPSIMPLEINTERNAL)pvMemory;
296	if ((uintptr_t)pvMemory & 31)
297	{
298	const unsigned off = 32 - ((uintptr_t)pvMemory & 31);
299	cbMemory -= off;
300	pHeapInt = (PRTHEAPSIMPLEINTERNAL)((uintptr_t)pvMemory + off);
301	}
302	cbMemory &= ~(RTHEAPSIMPLE_ALIGNMENT - 1);
303
304
305	/* Init the heap anchor block. */
306	pHeapInt->uMagic = RTHEAPSIMPLE_MAGIC;
307	pHeapInt->pvEnd = (uint8_t *)pHeapInt + cbMemory;
308	pHeapInt->cbHeap = cbMemory;
309	pHeapInt->cbFree = cbMemory
310	- sizeof(RTHEAPSIMPLEBLOCK)
311	- sizeof(RTHEAPSIMPLEINTERNAL);
312	pHeapInt->pFreeTail = pHeapInt->pFreeHead = (PRTHEAPSIMPLEFREE)(pHeapInt + 1);
313	for (unsigned i = 0; i < ELEMENTS(pHeapInt->auAlignment); i++)
314	pHeapInt->auAlignment[i] = ~(size_t)0;
315
316	/* Init the single free block. */
317	PRTHEAPSIMPLEFREE pFree = pHeapInt->pFreeHead;
318	pFree->Core.pNext = NULL;
319	pFree->Core.pPrev = NULL;
320	pFree->Core.pHeap = pHeapInt;
321	pFree->Core.fFlags = RTHEAPSIMPLEBLOCK_FLAGS_MAGIC \| RTHEAPSIMPLEBLOCK_FLAGS_FREE;
322	pFree->pNext = NULL;
323	pFree->pPrev = NULL;
324	pFree->cb = pHeapInt->cbFree;
325
326	*pHeap = pHeapInt;
327
328	#ifdef RTHEAPSIMPLE_STRICT
329	rtHeapSimpleAssertAll(pHeapInt);
330	#endif
331	return VINF_SUCCESS;
332	}
333
334
335
336	/**
337	* Allocates memory from the specified simple heap.
338	*
339	* @returns Pointer to the allocated memory block on success.
340	* @returns NULL if the request cannot be satisfied. (A VERR_NO_MEMORY condition.)
341	*
342	* @param Heap The heap to allocate the memory on.
343	* @param cb The requested heap block size.
344	* @param cbAlignment The requested heap block alignment. Pass 0 for default alignment.
345	* Must be a power of 2.
346	*/
347	RTDECL(void *) RTHeapSimpleAlloc(RTHEAPSIMPLE Heap, size_t cb, size_t cbAlignment)
348	{
349	PRTHEAPSIMPLEINTERNAL pHeapInt = Heap;
350
351	/*
352	* Validate and adjust the input.
353	*/
354	AssertPtrReturn(pHeapInt, NULL);
355	if (cb < RTHEAPSIMPLE_MIN_BLOCK)
356	cb = RTHEAPSIMPLE_MIN_BLOCK;
357	else
358	cb = RT_ALIGN_Z(cb, RTHEAPSIMPLE_ALIGNMENT);
359	if (!cbAlignment)
360	cbAlignment = RTHEAPSIMPLE_ALIGNMENT;
361	else
362	{
363	Assert(!(cbAlignment & (cbAlignment - 1)));
364	Assert((cbAlignment & ~(cbAlignment - 1)) == cbAlignment);
365	if (cbAlignment < RTHEAPSIMPLE_ALIGNMENT)
366	cbAlignment = RTHEAPSIMPLE_ALIGNMENT;
367	}
368
369	/*
370	* Do the allocation.
371	*/
372	PRTHEAPSIMPLEBLOCK pBlock = rtHeapSimpleAllocBlock(pHeapInt, cb, cbAlignment);
373	if (RT_LIKELY(pBlock))
374	{
375	void *pv = pBlock + 1;
376	return pv;
377	}
378	return NULL;
379	}
380
381
382	/**
383	* Allocates zeroed memory from the specified simple heap.
384	*
385	* @returns Pointer to the allocated memory block on success.
386	* @returns NULL if the request cannot be satisfied. (A VERR_NO_MEMORY condition.)
387	*
388	* @param Heap The heap to allocate the memory on.
389	* @param cb The requested heap block size.
390	* @param cbAlignment The requested heap block alignment. Pass 0 for default alignment.
391	* Must be a power of 2.
392	*/
393	RTDECL(void *) RTHeapSimpleAllocZ(RTHEAPSIMPLE Heap, size_t cb, size_t cbAlignment)
394	{
395	PRTHEAPSIMPLEINTERNAL pHeapInt = Heap;
396
397	/*
398	* Validate and adjust the input.
399	*/
400	AssertPtrReturn(pHeapInt, NULL);
401	if (cb < RTHEAPSIMPLE_MIN_BLOCK)
402	cb = RTHEAPSIMPLE_MIN_BLOCK;
403	else
404	cb = RT_ALIGN_Z(cb, RTHEAPSIMPLE_ALIGNMENT);
405	if (!cbAlignment)
406	cbAlignment = RTHEAPSIMPLE_ALIGNMENT;
407	else
408	{
409	Assert(!(cbAlignment & (cbAlignment - 1)));
410	Assert((cbAlignment & ~(cbAlignment - 1)) == cbAlignment);
411	if (cbAlignment < RTHEAPSIMPLE_ALIGNMENT)
412	cbAlignment = RTHEAPSIMPLE_ALIGNMENT;
413	}
414
415	/*
416	* Do the allocation.
417	*/
418	PRTHEAPSIMPLEBLOCK pBlock = rtHeapSimpleAllocBlock(pHeapInt, cb, cbAlignment);
419	if (RT_LIKELY(pBlock))
420	{
421	void *pv = pBlock + 1;
422	memset(pv, 0, cb);
423	return pv;
424	}
425	return NULL;
426	}
427
428
429	/**
430	* Allocates a block of memory from the specified heap.
431	*
432	* No parameter validation or adjustment is preformed.
433	*
434	* @returns Pointer to the allocated block.
435	* @returns NULL on failure.
436	* @param pHeap The heap.
437	* @param cb Size of the memory block to allocate.
438	* @param uAlignment The alignment specifications for the allocated block.
439	*/
440	static PRTHEAPSIMPLEBLOCK rtHeapSimpleAllocBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, size_t cb, size_t uAlignment)
441	{
442	#ifdef RTHEAPSIMPLE_STRICT
443	rtHeapSimpleAssertAll(pHeapInt);
444	#endif
445
446	/*
447	* Search for a fitting block from the lower end of the heap.
448	*/
449	PRTHEAPSIMPLEBLOCK pRet = NULL;
450	for (PRTHEAPSIMPLEFREE pFree = pHeapInt->pFreeHead;
451	pFree;
452	pFree = pFree->pNext)
453	{
454	ASSERT_BLOCK_FREE(pHeapInt, pFree);
455
456	/*
457	* Match for size and alignment.
458	*/
459	if (pFree->cb < cb)
460	continue;
461	uintptr_t offAlign = (uintptr_t)(&pFree->Core + 1) & (uAlignment - 1);
462	if (offAlign)
463	{
464	offAlign = uAlignment - offAlign;
465	if (pFree->cb - offAlign < cb)
466	continue;
467
468	/*
469	* Make a stack copy of the free block header and adjust the pointer.
470	*/
471	RTHEAPSIMPLEFREE Free = *pFree;
472	pFree = (PRTHEAPSIMPLEFREE)((uintptr_t)pFree + offAlign);
473
474	/*
475	* Donate offAlign bytes to the node in front of us.
476	* If we're the head node, we'll have to create a fake node. We'll
477	* mark it USED for simplicity.
478	*
479	* (Should this policy of donating memory to the guy in front of us
480	* cause big 'leaks', we could create a new free node if there is room
481	* for that.)
482	*/
483	PRTHEAPSIMPLEBLOCK pPrev = Free.Core.pPrev;
484	if (pPrev)
485	{
486	AssertMsg(!RTHEAPSIMPLEBLOCK_IS_FREE(pPrev), ("Impossible!\n"));
487	pPrev->pNext = &pFree->Core;
488	}
489	else
490	{
491	pPrev = (PRTHEAPSIMPLEBLOCK)(pHeapInt + 1);
492	Assert(pPrev == &pFree->Core);
493	pPrev->pPrev = NULL;
494	pPrev->pNext = &pFree->Core;
495	pPrev->pHeap = pHeapInt;
496	pPrev->fFlags = RTHEAPSIMPLEBLOCK_FLAGS_MAGIC;
497	}
498	pHeapInt->cbFree -= offAlign;
499
500	/*
501	* Recreate pFree in the new position and adjust the neighbours.
502	*/
503	*pFree = Free;
504
505	/* the core */
506	if (pFree->Core.pNext)
507	pFree->Core.pNext->pPrev = &pFree->Core;
508	pFree->Core.pPrev = pPrev;
509
510	/* the free part */
511	pFree->cb -= offAlign;
512	if (pFree->pNext)
513	pFree->pNext->pPrev = pFree;
514	else
515	pHeapInt->pFreeTail = pFree;
516	if (pFree->pPrev)
517	pFree->pPrev->pNext = pFree;
518	else
519	pHeapInt->pFreeHead = pFree;
520	ASSERT_BLOCK_FREE(pHeapInt, pFree);
521	ASSERT_BLOCK_USED(pHeapInt, pPrev);
522	}
523
524	/*
525	* Split off a new FREE block?
526	*/
527	if (pFree->cb >= cb + RT_ALIGN_Z(sizeof(RTHEAPSIMPLEFREE), RTHEAPSIMPLE_ALIGNMENT))
528	{
529	/*
530	* Move the FREE block up to make room for the new USED block.
531	*/
532	PRTHEAPSIMPLEFREE pNew = (PRTHEAPSIMPLEFREE)((uintptr_t)&pFree->Core + cb + sizeof(RTHEAPSIMPLEBLOCK));
533
534	pNew->Core.pNext = pFree->Core.pNext;
535	if (pFree->Core.pNext)
536	pFree->Core.pNext->pPrev = &pNew->Core;
537	pNew->Core.pPrev = &pFree->Core;
538	pNew->Core.pHeap = pHeapInt;
539	pNew->Core.fFlags = RTHEAPSIMPLEBLOCK_FLAGS_MAGIC \| RTHEAPSIMPLEBLOCK_FLAGS_FREE;
540
541	pNew->pNext = pFree->pNext;
542	if (pNew->pNext)
543	pNew->pNext->pPrev = pNew;
544	else
545	pHeapInt->pFreeTail = pNew;
546	pNew->pPrev = pFree->pPrev;
547	if (pNew->pPrev)
548	pNew->pPrev->pNext = pNew;
549	else
550	pHeapInt->pFreeHead = pNew;
551	pNew->cb = (pNew->Core.pNext ? (uintptr_t)pNew->Core.pNext : (uintptr_t)pHeapInt->pvEnd) \
552	- (uintptr_t)pNew - sizeof(RTHEAPSIMPLEBLOCK);
553	ASSERT_BLOCK_FREE(pHeapInt, pNew);
554
555	/*
556	* Update the old FREE node making it a USED node.
557	*/
558	pFree->Core.fFlags &= ~RTHEAPSIMPLEBLOCK_FLAGS_FREE;
559	pFree->Core.pNext = &pNew->Core;
560	pHeapInt->cbFree -= pFree->cb;
561	pHeapInt->cbFree += pNew->cb;
562	pRet = &pFree->Core;
563	ASSERT_BLOCK_USED(pHeapInt, pRet);
564	}
565	else
566	{
567	/*
568	* Link it out of the free list.
569	*/
570	if (pFree->pNext)
571	pFree->pNext->pPrev = pFree->pPrev;
572	else
573	pHeapInt->pFreeTail = pFree->pPrev;
574	if (pFree->pPrev)
575	pFree->pPrev->pNext = pFree->pNext;
576	else
577	pHeapInt->pFreeHead = pFree->pNext;
578
579	/*
580	* Convert it to a used block.
581	*/
582	pHeapInt->cbFree -= pFree->cb;
583	pFree->Core.fFlags &= ~RTHEAPSIMPLEBLOCK_FLAGS_FREE;
584	pRet = &pFree->Core;
585	ASSERT_BLOCK_USED(pHeapInt, pRet);
586	}
587	break;
588	}
589
590	#ifdef RTHEAPSIMPLE_STRICT
591	rtHeapSimpleAssertAll(pHeapInt);
592	#endif
593	return pRet;
594	}
595
596
597
598
599	/**
600	* Frees memory allocated from a simple heap.
601	*
602	* @param Heap The heap. This is optional and will only be used for strict assertions.
603	* @param pv The heap block returned by RTHeapSimple
604	*/
605	RTDECL(void) RTHeapSimpleFree(RTHEAPSIMPLE Heap, void *pv)
606	{
607	/*
608	* Validate input.
609	*/
610	if (!pv)
611	return;
612	AssertPtr(pv);
613	Assert(RT_ALIGN_P(pv, RTHEAPSIMPLE_ALIGNMENT) == pv);
614
615	/*
616	* Get the block and heap. If in strict mode, validate these.
617	*/
618	PRTHEAPSIMPLEBLOCK pBlock = (PRTHEAPSIMPLEBLOCK)pv - 1;
619	PRTHEAPSIMPLEINTERNAL pHeapInt = pBlock->pHeap;
620	ASSERT_BLOCK_USED(pHeapInt, pBlock);
621	ASSERT_ANCHOR(pHeapInt);
622	Assert(pHeapInt == (PRTHEAPSIMPLEINTERNAL)Heap \|\| !Heap);
623
624	#ifdef RTHEAPSIMPLE_FREE_POISON
625	/*
626	* Poison the block.
627	*/
628	const size_t cbBlock = (pBlock->pNext ? (uintptr_t)pBlock->pNext : (uintptr_t)pHeapInt->pvEnd)
629	- (uintptr_t)pBlock - sizeof(RTHEAPSIMPLEBLOCK);
630	memset(pBlock + 1, RTHEAPSIMPLE_FREE_POISON, cbBlock);
631	#endif
632
633	/*
634	* Call worker which does the actual job.
635	*/
636	rtHeapSimpleFreeBlock(pHeapInt, pBlock);
637	}
638
639
640	/**
641	* Free memory a memory block.
642	*
643	* @param pHeapInt The heap.
644	* @param pBlock The memory block to free.
645	*/
646	static void rtHeapSimpleFreeBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, PRTHEAPSIMPLEBLOCK pBlock)
647	{
648	PRTHEAPSIMPLEFREE pFree = (PRTHEAPSIMPLEFREE)pBlock;
649
650	#ifdef RTHEAPSIMPLE_STRICT
651	rtHeapSimpleAssertAll(pHeapInt);
652	#endif
653
654	/*
655	* Look for the closest free list blocks by walking the blocks right
656	* of us (both list are sorted on address).
657	*/
658	PRTHEAPSIMPLEFREE pLeft = NULL;
659	PRTHEAPSIMPLEFREE pRight = NULL;
660	if (pHeapInt->pFreeTail)
661	{
662	pRight = (PRTHEAPSIMPLEFREE)pFree->Core.pNext;
663	while (pRight && !RTHEAPSIMPLEBLOCK_IS_FREE(&pRight->Core))
664	{
665	ASSERT_BLOCK(pHeapInt, &pRight->Core);
666	pRight = (PRTHEAPSIMPLEFREE)pRight->Core.pNext;
667	}
668	if (!pRight)
669	pLeft = pHeapInt->pFreeTail;
670	else
671	{
672	ASSERT_BLOCK_FREE(pHeapInt, pRight);
673	pLeft = pRight->pPrev;
674	}
675	if (pLeft)
676	ASSERT_BLOCK_FREE(pHeapInt, pLeft);
677	}
678	AssertMsgReturnVoid(pLeft != pFree, ("Freed twice! pv=%p (pBlock=%p)\n", pBlock + 1, pBlock));
679	ASSERT_L(pLeft, pFree);
680	Assert(!pRight \|\| (uintptr_t)pRight > (uintptr_t)pFree);
681	Assert(!pLeft \|\| pLeft->pNext == pRight);
682
683	/*
684	* Insert at the head of the free block list?
685	*/
686	if (!pLeft)
687	{
688	Assert(pRight == pHeapInt->pFreeHead);
689	pFree->Core.fFlags \|= RTHEAPSIMPLEBLOCK_FLAGS_FREE;
690	pFree->pPrev = NULL;
691	pFree->pNext = pRight;
692	if (pRight)
693	pRight->pPrev = pFree;
694	else
695	pHeapInt->pFreeTail = pFree;
696	pHeapInt->pFreeHead = pFree;
697	}
698	else
699	{
700	/*
701	* Can we merge with left hand free block?
702	*/
703	if (pLeft->Core.pNext == &pFree->Core)
704	{
705	pLeft->Core.pNext = pFree->Core.pNext;
706	if (pFree->Core.pNext)
707	pFree->Core.pNext->pPrev = &pLeft->Core;
708	pHeapInt->cbFree -= pLeft->cb;
709	pFree = pLeft;
710	}
711	/*
712	* No, just link it into the free list then.
713	*/
714	else
715	{
716	pFree->Core.fFlags \|= RTHEAPSIMPLEBLOCK_FLAGS_FREE;
717	pFree->pNext = pRight;
718	pFree->pPrev = pLeft;
719	pLeft->pNext = pFree;
720	if (pRight)
721	pRight->pPrev = pFree;
722	else
723	pHeapInt->pFreeTail = pFree;
724	}
725	}
726
727	/*
728	* Can we merge with right hand free block?
729	*/
730	if ( pRight
731	&& pRight->Core.pPrev == &pFree->Core)
732	{
733	/* core */
734	pFree->Core.pNext = pRight->Core.pNext;
735	if (pRight->Core.pNext)
736	pRight->Core.pNext->pPrev = &pFree->Core;
737
738	/* free */
739	pFree->pNext = pRight->pNext;
740	if (pRight->pNext)
741	pRight->pNext->pPrev = pFree;
742	else
743	pHeapInt->pFreeTail = pFree;
744	pHeapInt->cbFree -= pRight->cb;
745	}
746
747	/*
748	* Calculate the size and update free stats.
749	*/
750	pFree->cb = (pFree->Core.pNext ? (uintptr_t)pFree->Core.pNext : (uintptr_t)pHeapInt->pvEnd)
751	- (uintptr_t)pFree - sizeof(RTHEAPSIMPLEBLOCK);
752	pHeapInt->cbFree += pFree->cb;
753	ASSERT_BLOCK_FREE(pHeapInt, pFree);
754
755	#ifdef RTHEAPSIMPLE_STRICT
756	rtHeapSimpleAssertAll(pHeapInt);
757	#endif
758	}
759
760
761	#ifdef RTHEAPSIMPLE_STRICT
762	/**
763	* Internal consitency check (relying on assertions).
764	* @param pHeapInt
765	*/
766	static void rtHeapSimpleAssertAll(PRTHEAPSIMPLEINTERNAL pHeapInt)
767	{
768	PRTHEAPSIMPLEFREE pPrev = NULL;
769	PRTHEAPSIMPLEFREE pPrevFree = NULL;
770	for (PRTHEAPSIMPLEFREE pBlock = (PRTHEAPSIMPLEFREE)(pHeapInt + 1);
771	pBlock;
772	pBlock = (PRTHEAPSIMPLEFREE)pBlock->Core.pNext)
773	{
774	if (RTHEAPSIMPLEBLOCK_IS_FREE(&pBlock->Core))
775	{
776	ASSERT_BLOCK_FREE(pHeapInt, pBlock);
777	Assert(pBlock->pPrev == pPrevFree);
778	Assert(pPrevFree \|\| pHeapInt->pFreeHead == pBlock);
779	pPrevFree = pBlock;
780	}
781	else
782	ASSERT_BLOCK_USED(pHeapInt, &pBlock->Core);
783	Assert(!pPrev \|\| pPrev == (PRTHEAPSIMPLEFREE)pBlock->Core.pPrev);
784	pPrev = pBlock;
785	}
786	Assert(pHeapInt->pFreeTail == pPrevFree);
787	}
788	#endif
789
790
791	/**
792	* Gets the size of the specified heap block.
793	*
794	* @returns The actual size of the heap block.
795	* @returns 0 if \a pv is NULL or it doesn't point to a valid heap block. An invalid \a pv
796	* can also cause traps or trigger assertions.
797	* @param Heap The heap. This is optional and will only be used for strict assertions.
798	* @param pv The heap block returned by RTHeapSimple
799	*/
800	RTDECL(size_t) RTHeapSimpleSize(RTHEAPSIMPLE Heap, void *pv)
801	{
802	/*
803	* Validate input.
804	*/
805	if (!pv)
806	return 0;
807	AssertPtrReturn(pv, 0);
808	AssertReturn(RT_ALIGN_P(pv, RTHEAPSIMPLE_ALIGNMENT) == pv, 0);
809
810	/*
811	* Get the block and heap. If in strict mode, validate these.
812	*/
813	PRTHEAPSIMPLEBLOCK pBlock = (PRTHEAPSIMPLEBLOCK)pv - 1;
814	PRTHEAPSIMPLEINTERNAL pHeapInt = pBlock->pHeap;
815	ASSERT_BLOCK_USED(pHeapInt, pBlock);
816	ASSERT_ANCHOR(pHeapInt);
817	Assert(pHeapInt == (PRTHEAPSIMPLEINTERNAL)Heap \|\| !Heap);
818
819	/*
820	* Calculate the block size.
821	*/
822	const size_t cbBlock = (pBlock->pNext ? (uintptr_t)pBlock->pNext : (uintptr_t)pHeapInt->pvEnd)
823	- (uintptr_t)pBlock- sizeof(RTHEAPSIMPLEBLOCK);
824	return cbBlock;
825	}
826
827
828	/**
829	* Gets the size of the heap.
830	*
831	* This size includes all the internal heap structures. So, even if the heap is
832	* empty the RTHeapSimpleGetFreeSize() will never reach the heap size returned
833	* by this function.
834	*
835	* @returns The heap size.
836	* @returns 0 if heap was safely detected as being bad.
837	* @param Heap The heap.
838	*/
839	RTDECL(size_t) RTHeapSimpleGetHeapSize(RTHEAPSIMPLE Heap)
840	{
841	if (Heap == NIL_RTHEAPSIMPLE)
842	return 0;
843	PRTHEAPSIMPLEINTERNAL pHeapInt = Heap;
844	AssertPtrReturn(pHeapInt, 0);
845	ASSERT_ANCHOR(pHeapInt);
846	return pHeapInt->cbHeap;
847	}
848
849
850	/**
851	* Returns the sum of all free heap blocks.
852	*
853	* This is the amount of memory you can theoretically allocate
854	* if you do allocations exactly matching the free blocks.
855	*
856	* @returns The size of the free blocks.
857	* @returns 0 if heap was safely detected as being bad.
858	* @param Heap The heap.
859	*/
860	RTDECL(size_t) RTHeapSimpleGetFreeSize(RTHEAPSIMPLE Heap)
861	{
862	if (Heap == NIL_RTHEAPSIMPLE)
863	return 0;
864	PRTHEAPSIMPLEINTERNAL pHeapInt = Heap;
865	AssertPtrReturn(pHeapInt, 0);
866	ASSERT_ANCHOR(pHeapInt);
867	return pHeapInt->cbFree;
868	}
869
870
871	/**
872	* Dumps the hypervisor heap.
873	*
874	* @param Heap The heap handle.
875	* @param pfnPrintf Printf like function that groks IPRT formatting.
876	*/
877	RTDECL(void) RTHeapSimpleDump(RTHEAPSIMPLE Heap, PFNRTHEAPSIMPLEPRINTF pfnPrintf)
878	{
879	PRTHEAPSIMPLEINTERNAL pHeapInt = (PRTHEAPSIMPLEINTERNAL)Heap;
880	pfnPrintf("** Dumping Heap %p - cbHeap=%zx cbFree=%zx **\n",
881	Heap, pHeapInt->cbHeap, pHeapInt->cbFree);
882
883	for (PRTHEAPSIMPLEFREE pBlock = (PRTHEAPSIMPLEFREE)(pHeapInt + 1);
884	pBlock;
885	pBlock = (PRTHEAPSIMPLEFREE)pBlock->Core.pNext)
886	{
887	size_t cb = (pBlock->pNext ? (uintptr_t)pBlock->Core.pNext : (uintptr_t)pHeapInt->pvEnd)
888	- (uintptr_t)pBlock - sizeof(RTHEAPSIMPLEBLOCK);
889	if (RTHEAPSIMPLEBLOCK_IS_FREE(&pBlock->Core))
890	pfnPrintf("%p %06x FREE pNext=%p pPrev=%p fFlags=%#x cb=%#06x : cb=%#06x pNext=%p pPrev=%p\n",
891	pBlock, (uintptr_t)pBlock - (uintptr_t)(pHeapInt + 1), pBlock->Core.pNext, pBlock->Core.pPrev, pBlock->Core.fFlags, cb,
892	pBlock->cb, pBlock->pNext, pBlock->pPrev);
893	else
894	pfnPrintf("%p %06x USED pNext=%p pPrev=%p fFlags=%#x cb=%#06x\n",
895	pBlock, (uintptr_t)pBlock - (uintptr_t)(pHeapInt + 1), pBlock->Core.pNext, pBlock->Core.pPrev, pBlock->Core.fFlags, cb);
896	}
897	pfnPrintf("** Done dumping Heap %p **\n", Heap);
898	}
899

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source: vbox/trunk/src/VBox/Runtime/alloc/heapsimple.cpp@ 329

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