heapsimple.cpp@ 1816

Last change on this file since 1816 was 1816, checked in by vboxsync, 18 years ago
moved magics to a common header to avoid duplicating the same defines all over the place.
Property svn:keywords set to `Id`
File size: 30.0 KB

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1	/* $Id: heapsimple.cpp 1816 2007-03-29 18:59:35Z 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	#include "internal/magics.h"
36
37
38	/*******************************************************************************
39	* Structures and Typedefs *
40	*******************************************************************************/
41	/** Pointer to the heap anchor block. */
42	typedef struct RTHEAPSIMPLEINTERNAL *PRTHEAPSIMPLEINTERNAL;
43	/** Pointer to a heap block. */
44	typedef struct RTHEAPSIMPLEBLOCK *PRTHEAPSIMPLEBLOCK;
45	/** Pointer to a free heap block. */
46	typedef struct RTHEAPSIMPLEFREE *PRTHEAPSIMPLEFREE;
47
48	/**
49	* Structure describing a simple heap block.
50	* If this block is allocated, it is followed by the user user data.
51	* If this block is free, see RTHEAPSIMPLEFREE.
52	*/
53	typedef struct RTHEAPSIMPLEBLOCK
54	{
55	/** The next block in the global block list. */
56	PRTHEAPSIMPLEBLOCK pNext;
57	/** The previous block in the global block list. */
58	PRTHEAPSIMPLEBLOCK pPrev;
59	/** Pointer to the heap anchor block. */
60	PRTHEAPSIMPLEINTERNAL pHeap;
61	/** Flags + magic. */
62	uintptr_t fFlags;
63	} RTHEAPSIMPLEBLOCK;
64	AssertCompileSizeAlignment(RTHEAPSIMPLEBLOCK, 16);
65
66	/** The block is free if this flag is set. When cleared it's allocated. */
67	#define RTHEAPSIMPLEBLOCK_FLAGS_FREE ((uintptr_t)BIT(0))
68	/** The magic value. */
69	#define RTHEAPSIMPLEBLOCK_FLAGS_MAGIC ((uintptr_t)0xabcdef00)
70	/** The mask that needs to be applied to RTHEAPSIMPLEBLOCK::fFalgs to obtain the magic value. */
71	#define RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK (~(uintptr_t)BIT(0))
72
73	/**
74	* Checks if the specified block is valid or not.
75	* @returns boolean answer.
76	* @param pBlock Pointer to a RTHEAPSIMPLEBLOCK structure.
77	*/
78	#define RTHEAPSIMPLEBLOCK_IS_VALID(pBlock) \
79	( ((pBlock)->fFlags & RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK) == RTHEAPSIMPLEBLOCK_FLAGS_MAGIC )
80
81	/**
82	* Checks if the specified block is valid and in use.
83	* @returns boolean answer.
84	* @param pBlock Pointer to a RTHEAPSIMPLEBLOCK structure.
85	*/
86	#define RTHEAPSIMPLEBLOCK_IS_VALID_USED(pBlock) \
87	( ((pBlock)->fFlags & (RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK \| RTHEAPSIMPLEBLOCK_FLAGS_FREE)) \
88	== RTHEAPSIMPLEBLOCK_FLAGS_MAGIC )
89
90	/**
91	* Checks if the specified block is valid and free.
92	* @returns boolean answer.
93	* @param pBlock Pointer to a RTHEAPSIMPLEBLOCK structure.
94	*/
95	#define RTHEAPSIMPLEBLOCK_IS_VALID_FREE(pBlock) \
96	( ((pBlock)->fFlags & (RTHEAPSIMPLEBLOCK_FLAGS_MAGIC_MASK \| RTHEAPSIMPLEBLOCK_FLAGS_FREE)) \
97	== (RTHEAPSIMPLEBLOCK_FLAGS_MAGIC \| RTHEAPSIMPLEBLOCK_FLAGS_FREE) )
98
99	/**
100	* Checks if the specified block is free or not.
101	* @returns boolean answer.
102	* @param pBlock Pointer to a valid RTHEAPSIMPLEBLOCK structure.
103	*/
104	#define RTHEAPSIMPLEBLOCK_IS_FREE(pBlock) (!!((pBlock)->fFlags & RTHEAPSIMPLEBLOCK_FLAGS_FREE))
105
106	/**
107	* A free heap block.
108	* This is an extended version of RTHEAPSIMPLEBLOCK that takes the unused
109	* user data to store free list pointers and a cached size value.
110	*/
111	typedef struct RTHEAPSIMPLEFREE
112	{
113	/** Core stuff. */
114	RTHEAPSIMPLEBLOCK Core;
115	/** Pointer to the next free block. */
116	PRTHEAPSIMPLEFREE pNext;
117	/** Pointer to the previous free block. */
118	PRTHEAPSIMPLEFREE pPrev;
119	/** The size of the block (excluding the RTHEAPSIMPLEBLOCK part). */
120	size_t cb;
121	/** An alignment filler to make it a multiple of (sizeof(void ) 2). */
122	size_t Alignment;
123	} RTHEAPSIMPLEFREE;
124
125
126	/**
127	* The heap anchor block.
128	* This structure is placed at the head of the memory block specified to RTHeapSimpleInit(),
129	* which means that the first RTHEAPSIMPLEBLOCK appears immediately after this structure.
130	*/
131	typedef struct RTHEAPSIMPLEINTERNAL
132	{
133	/** The typical magic (RTHEAPSIMPLE_MAGIC). */
134	size_t uMagic;
135	/** The heap size. (This structure is not included!) */
136	size_t cbHeap;
137	/** Pointer to the end of the heap. */
138	void *pvEnd;
139	/** The amount of free memory in the heap. */
140	size_t cbFree;
141	/** Free head pointer. */
142	PRTHEAPSIMPLEFREE pFreeHead;
143	/** Free tail pointer. */
144	PRTHEAPSIMPLEFREE pFreeTail;
145	/** Make the size of this structure is a multiple of 32. */
146	size_t auAlignment[2];
147	} RTHEAPSIMPLEINTERNAL;
148	AssertCompileSizeAlignment(RTHEAPSIMPLEINTERNAL, 32);
149
150
151	/** The minimum allocation size. */
152	#define RTHEAPSIMPLE_MIN_BLOCK (sizeof(RTHEAPSIMPLEBLOCK))
153	AssertCompile(RTHEAPSIMPLE_MIN_BLOCK >= sizeof(RTHEAPSIMPLEBLOCK));
154	AssertCompile(RTHEAPSIMPLE_MIN_BLOCK >= sizeof(RTHEAPSIMPLEFREE) - sizeof(RTHEAPSIMPLEBLOCK));
155
156	/** The minimum and default alignment. */
157	#define RTHEAPSIMPLE_ALIGNMENT (sizeof(RTHEAPSIMPLEBLOCK))
158
159
160	/*******************************************************************************
161	* Defined Constants And Macros *
162	*******************************************************************************/
163	#ifdef RT_STRICT
164	# define RTHEAPSIMPLE_STRICT 1
165	#endif
166
167	#define ASSERT_L(a, b) AssertMsg((uintptr_t)(a) < (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
168	#define ASSERT_LE(a, b) AssertMsg((uintptr_t)(a) <= (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
169	#define ASSERT_G(a, b) AssertMsg((uintptr_t)(a) > (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
170	#define ASSERT_GE(a, b) AssertMsg((uintptr_t)(a) >= (uintptr_t)(b), ("a=%p b=%p\n", (uintptr_t)(a), (uintptr_t)(b)))
171	#define ASSERT_ALIGN(a) AssertMsg(!((uintptr_t)(a) & (RTHEAPSIMPLE_ALIGNMENT - 1)), ("a=%p\n", (uintptr_t)(a)))
172
173	#define ASSERT_PREV(pHeapInt, pBlock) \
174	do { ASSERT_ALIGN((pBlock)->pPrev); \
175	if ((pBlock)->pPrev) \
176	{ \
177	ASSERT_L((pBlock)->pPrev, (pBlock)); \
178	ASSERT_GE((pBlock)->pPrev, (pHeapInt) + 1); \
179	} \
180	else \
181	Assert((pBlock) == (PRTHEAPSIMPLEBLOCK)((pHeapInt) + 1)); \
182	} while (0)
183
184	#define ASSERT_NEXT(pHeap, pBlock) \
185	do { ASSERT_ALIGN((pBlock)->pNext); \
186	if ((pBlock)->pNext) \
187	{ \
188	ASSERT_L((pBlock)->pNext, (pHeapInt)->pvEnd); \
189	ASSERT_G((pBlock)->pNext, (pBlock)); \
190	} \
191	} while (0)
192
193	#define ASSERT_BLOCK(pHeapInt, pBlock) \
194	do { AssertMsg(RTHEAPSIMPLEBLOCK_IS_VALID(pBlock), ("%#x\n", (pBlock)->fFlags)); \
195	AssertMsg((pBlock)->pHeap == (pHeapInt), ("%p != %p\n", (pBlock)->pHeap, (pHeapInt))); \
196	ASSERT_GE((pBlock), (pHeapInt) + 1); \
197	ASSERT_L((pBlock), (pHeapInt)->pvEnd); \
198	ASSERT_NEXT(pHeapInt, pBlock); \
199	ASSERT_PREV(pHeapInt, pBlock); \
200	} while (0)
201
202	#define ASSERT_BLOCK_USED(pHeapInt, pBlock) \
203	do { AssertMsg(RTHEAPSIMPLEBLOCK_IS_VALID_USED((pBlock)), ("%#x\n", (pBlock)->fFlags)); \
204	AssertMsg((pBlock)->pHeap == (pHeapInt), ("%p != %p\n", (pBlock)->pHeap, (pHeapInt))); \
205	ASSERT_GE((pBlock), (pHeapInt) + 1); \
206	ASSERT_L((pBlock), (pHeapInt)->pvEnd); \
207	ASSERT_NEXT(pHeapInt, pBlock); \
208	ASSERT_PREV(pHeapInt, pBlock); \
209	} while (0)
210
211	#define ASSERT_FREE_PREV(pHeapInt, pBlock) \
212	do { ASSERT_ALIGN((pBlock)->pPrev); \
213	if ((pBlock)->pPrev) \
214	{ \
215	ASSERT_GE((pBlock)->pPrev, (pHeapInt)->pFreeHead); \
216	ASSERT_L((pBlock)->pPrev, (pBlock)); \
217	ASSERT_LE((pBlock)->pPrev, (pBlock)->Core.pPrev); \
218	} \
219	else \
220	Assert((pBlock) == (pHeapInt)->pFreeHead); \
221	} while (0)
222
223	#define ASSERT_FREE_NEXT(pHeapInt, pBlock) \
224	do { ASSERT_ALIGN((pBlock)->pNext); \
225	if ((pBlock)->pNext) \
226	{ \
227	ASSERT_LE((pBlock)->pNext, (pHeapInt)->pFreeTail); \
228	ASSERT_G((pBlock)->pNext, (pBlock)); \
229	ASSERT_GE((pBlock)->pNext, (pBlock)->Core.pNext); \
230	} \
231	else \
232	Assert((pBlock) == (pHeapInt)->pFreeTail); \
233	} while (0)
234
235	#ifdef RTHEAPSIMPLE_STRICT
236	# define ASSERT_FREE_CB(pHeapInt, pBlock) \
237	do { size_t cbCalc = ((pBlock)->Core.pNext ? (uintptr_t)(pBlock)->Core.pNext : (uintptr_t)(pHeapInt)->pvEnd) \
238	- (uintptr_t)(pBlock) - sizeof(RTHEAPSIMPLEBLOCK); \
239	AssertMsg((pBlock)->cb == cbCalc, ("cb=%#zx cbCalc=%#zx\n", (pBlock)->cb, cbCalc)); \
240	} while (0)
241	#else
242	# define ASSERT_FREE_CB(pHeapInt, pBlock) do {} while (0)
243	#endif
244
245	/** Asserts that a free block is valid. */
246	#define ASSERT_BLOCK_FREE(pHeapInt, pBlock) \
247	do { ASSERT_BLOCK(pHeapInt, &(pBlock)->Core); \
248	Assert(RTHEAPSIMPLEBLOCK_IS_VALID_FREE(&(pBlock)->Core)); \
249	ASSERT_GE((pBlock), (pHeapInt)->pFreeHead); \
250	ASSERT_LE((pBlock), (pHeapInt)->pFreeTail); \
251	ASSERT_FREE_NEXT(pHeapInt, pBlock); \
252	ASSERT_FREE_PREV(pHeapInt, pBlock); \
253	ASSERT_FREE_CB(pHeapInt, pBlock); \
254	} while (0)
255
256	/** Asserts that the heap anchor block is ok. */
257	#define ASSERT_ANCHOR(pHeapInt) \
258	do { AssertPtr(pHeapInt);\
259	Assert((pHeapInt)->uMagic == RTHEAPSIMPLE_MAGIC); \
260	} while (0)
261
262
263	/*******************************************************************************
264	* Internal Functions *
265	*******************************************************************************/
266	#ifdef RTHEAPSIMPLE_STRICT
267	static void rtHeapSimpleAssertAll(PRTHEAPSIMPLEINTERNAL pHeapInt);
268	#endif
269	static PRTHEAPSIMPLEBLOCK rtHeapSimpleAllocBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, size_t cb, size_t uAlignment);
270	static void rtHeapSimpleFreeBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, PRTHEAPSIMPLEBLOCK pBlock);
271
272
273	/**
274	* Initializes the heap.
275	*
276	* @returns IPRT status code on success.
277	* @param pHeap Where to store the heap anchor block on success.
278	* @param pvMemory Pointer to the heap memory.
279	* @param cbMemory The size of the heap memory.
280	*/
281	RTDECL(int) RTHeapSimpleInit(PRTHEAPSIMPLE pHeap, void *pvMemory, size_t cbMemory)
282	{
283	/*
284	* Validate input. The imposed minimum heap size is just a convenien value.
285	*/
286	AssertReturn(cbMemory >= PAGE_SIZE, VERR_INVALID_PARAMETER);
287	AssertPtrReturn(pvMemory, VERR_INVALID_POINTER);
288	AssertReturn((uintptr_t)pvMemory + (cbMemory - 1) > (uintptr_t)cbMemory, VERR_INVALID_PARAMETER);
289
290	/*
291	* Place the heap anchor block at the start of the heap memory,
292	* enforce 32 byte alignment of it. Also align the heap size correctly.
293	*/
294	PRTHEAPSIMPLEINTERNAL pHeapInt = (PRTHEAPSIMPLEINTERNAL)pvMemory;
295	if ((uintptr_t)pvMemory & 31)
296	{
297	const unsigned off = 32 - ((uintptr_t)pvMemory & 31);
298	cbMemory -= off;
299	pHeapInt = (PRTHEAPSIMPLEINTERNAL)((uintptr_t)pvMemory + off);
300	}
301	cbMemory &= ~(RTHEAPSIMPLE_ALIGNMENT - 1);
302
303
304	/* Init the heap anchor block. */
305	pHeapInt->uMagic = RTHEAPSIMPLE_MAGIC;
306	pHeapInt->pvEnd = (uint8_t *)pHeapInt + cbMemory;
307	pHeapInt->cbHeap = cbMemory;
308	pHeapInt->cbFree = cbMemory
309	- sizeof(RTHEAPSIMPLEBLOCK)
310	- sizeof(RTHEAPSIMPLEINTERNAL);
311	pHeapInt->pFreeTail = pHeapInt->pFreeHead = (PRTHEAPSIMPLEFREE)(pHeapInt + 1);
312	unsigned i;
313	for (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	PRTHEAPSIMPLEFREE pFree;
451	for (pFree = pHeapInt->pFreeHead;
452	pFree;
453	pFree = pFree->pNext)
454	{
455	ASSERT_BLOCK_FREE(pHeapInt, pFree);
456
457	/*
458	* Match for size and alignment.
459	*/
460	if (pFree->cb < cb)
461	continue;
462	uintptr_t offAlign = (uintptr_t)(&pFree->Core + 1) & (uAlignment - 1);
463	if (offAlign)
464	{
465	offAlign = uAlignment - offAlign;
466	if (pFree->cb - offAlign < cb)
467	continue;
468
469	/*
470	* Make a stack copy of the free block header and adjust the pointer.
471	*/
472	RTHEAPSIMPLEFREE Free = *pFree;
473	pFree = (PRTHEAPSIMPLEFREE)((uintptr_t)pFree + offAlign);
474
475	/*
476	* Donate offAlign bytes to the node in front of us.
477	* If we're the head node, we'll have to create a fake node. We'll
478	* mark it USED for simplicity.
479	*
480	* (Should this policy of donating memory to the guy in front of us
481	* cause big 'leaks', we could create a new free node if there is room
482	* for that.)
483	*/
484	PRTHEAPSIMPLEBLOCK pPrev = Free.Core.pPrev;
485	if (pPrev)
486	{
487	AssertMsg(!RTHEAPSIMPLEBLOCK_IS_FREE(pPrev), ("Impossible!\n"));
488	pPrev->pNext = &pFree->Core;
489	}
490	else
491	{
492	pPrev = (PRTHEAPSIMPLEBLOCK)(pHeapInt + 1);
493	Assert(pPrev == &pFree->Core);
494	pPrev->pPrev = NULL;
495	pPrev->pNext = &pFree->Core;
496	pPrev->pHeap = pHeapInt;
497	pPrev->fFlags = RTHEAPSIMPLEBLOCK_FLAGS_MAGIC;
498	}
499	pHeapInt->cbFree -= offAlign;
500
501	/*
502	* Recreate pFree in the new position and adjust the neighbours.
503	*/
504	*pFree = Free;
505
506	/* the core */
507	if (pFree->Core.pNext)
508	pFree->Core.pNext->pPrev = &pFree->Core;
509	pFree->Core.pPrev = pPrev;
510
511	/* the free part */
512	pFree->cb -= offAlign;
513	if (pFree->pNext)
514	pFree->pNext->pPrev = pFree;
515	else
516	pHeapInt->pFreeTail = pFree;
517	if (pFree->pPrev)
518	pFree->pPrev->pNext = pFree;
519	else
520	pHeapInt->pFreeHead = pFree;
521	ASSERT_BLOCK_FREE(pHeapInt, pFree);
522	ASSERT_BLOCK_USED(pHeapInt, pPrev);
523	}
524
525	/*
526	* Split off a new FREE block?
527	*/
528	if (pFree->cb >= cb + RT_ALIGN_Z(sizeof(RTHEAPSIMPLEFREE), RTHEAPSIMPLE_ALIGNMENT))
529	{
530	/*
531	* Move the FREE block up to make room for the new USED block.
532	*/
533	PRTHEAPSIMPLEFREE pNew = (PRTHEAPSIMPLEFREE)((uintptr_t)&pFree->Core + cb + sizeof(RTHEAPSIMPLEBLOCK));
534
535	pNew->Core.pNext = pFree->Core.pNext;
536	if (pFree->Core.pNext)
537	pFree->Core.pNext->pPrev = &pNew->Core;
538	pNew->Core.pPrev = &pFree->Core;
539	pNew->Core.pHeap = pHeapInt;
540	pNew->Core.fFlags = RTHEAPSIMPLEBLOCK_FLAGS_MAGIC \| RTHEAPSIMPLEBLOCK_FLAGS_FREE;
541
542	pNew->pNext = pFree->pNext;
543	if (pNew->pNext)
544	pNew->pNext->pPrev = pNew;
545	else
546	pHeapInt->pFreeTail = pNew;
547	pNew->pPrev = pFree->pPrev;
548	if (pNew->pPrev)
549	pNew->pPrev->pNext = pNew;
550	else
551	pHeapInt->pFreeHead = pNew;
552	pNew->cb = (pNew->Core.pNext ? (uintptr_t)pNew->Core.pNext : (uintptr_t)pHeapInt->pvEnd) \
553	- (uintptr_t)pNew - sizeof(RTHEAPSIMPLEBLOCK);
554	ASSERT_BLOCK_FREE(pHeapInt, pNew);
555
556	/*
557	* Update the old FREE node making it a USED node.
558	*/
559	pFree->Core.fFlags &= ~RTHEAPSIMPLEBLOCK_FLAGS_FREE;
560	pFree->Core.pNext = &pNew->Core;
561	pHeapInt->cbFree -= pFree->cb;
562	pHeapInt->cbFree += pNew->cb;
563	pRet = &pFree->Core;
564	ASSERT_BLOCK_USED(pHeapInt, pRet);
565	}
566	else
567	{
568	/*
569	* Link it out of the free list.
570	*/
571	if (pFree->pNext)
572	pFree->pNext->pPrev = pFree->pPrev;
573	else
574	pHeapInt->pFreeTail = pFree->pPrev;
575	if (pFree->pPrev)
576	pFree->pPrev->pNext = pFree->pNext;
577	else
578	pHeapInt->pFreeHead = pFree->pNext;
579
580	/*
581	* Convert it to a used block.
582	*/
583	pHeapInt->cbFree -= pFree->cb;
584	pFree->Core.fFlags &= ~RTHEAPSIMPLEBLOCK_FLAGS_FREE;
585	pRet = &pFree->Core;
586	ASSERT_BLOCK_USED(pHeapInt, pRet);
587	}
588	break;
589	}
590
591	#ifdef RTHEAPSIMPLE_STRICT
592	rtHeapSimpleAssertAll(pHeapInt);
593	#endif
594	return pRet;
595	}
596
597
598
599
600	/**
601	* Frees memory allocated from a simple heap.
602	*
603	* @param Heap The heap. This is optional and will only be used for strict assertions.
604	* @param pv The heap block returned by RTHeapSimple
605	*/
606	RTDECL(void) RTHeapSimpleFree(RTHEAPSIMPLE Heap, void *pv)
607	{
608	/*
609	* Validate input.
610	*/
611	if (!pv)
612	return;
613	AssertPtr(pv);
614	Assert(RT_ALIGN_P(pv, RTHEAPSIMPLE_ALIGNMENT) == pv);
615
616	/*
617	* Get the block and heap. If in strict mode, validate these.
618	*/
619	PRTHEAPSIMPLEBLOCK pBlock = (PRTHEAPSIMPLEBLOCK)pv - 1;
620	PRTHEAPSIMPLEINTERNAL pHeapInt = pBlock->pHeap;
621	ASSERT_BLOCK_USED(pHeapInt, pBlock);
622	ASSERT_ANCHOR(pHeapInt);
623	Assert(pHeapInt == (PRTHEAPSIMPLEINTERNAL)Heap \|\| !Heap);
624
625	#ifdef RTHEAPSIMPLE_FREE_POISON
626	/*
627	* Poison the block.
628	*/
629	const size_t cbBlock = (pBlock->pNext ? (uintptr_t)pBlock->pNext : (uintptr_t)pHeapInt->pvEnd)
630	- (uintptr_t)pBlock - sizeof(RTHEAPSIMPLEBLOCK);
631	memset(pBlock + 1, RTHEAPSIMPLE_FREE_POISON, cbBlock);
632	#endif
633
634	/*
635	* Call worker which does the actual job.
636	*/
637	rtHeapSimpleFreeBlock(pHeapInt, pBlock);
638	}
639
640
641	/**
642	* Free memory a memory block.
643	*
644	* @param pHeapInt The heap.
645	* @param pBlock The memory block to free.
646	*/
647	static void rtHeapSimpleFreeBlock(PRTHEAPSIMPLEINTERNAL pHeapInt, PRTHEAPSIMPLEBLOCK pBlock)
648	{
649	PRTHEAPSIMPLEFREE pFree = (PRTHEAPSIMPLEFREE)pBlock;
650
651	#ifdef RTHEAPSIMPLE_STRICT
652	rtHeapSimpleAssertAll(pHeapInt);
653	#endif
654
655	/*
656	* Look for the closest free list blocks by walking the blocks right
657	* of us (both list are sorted on address).
658	*/
659	PRTHEAPSIMPLEFREE pLeft = NULL;
660	PRTHEAPSIMPLEFREE pRight = NULL;
661	if (pHeapInt->pFreeTail)
662	{
663	pRight = (PRTHEAPSIMPLEFREE)pFree->Core.pNext;
664	while (pRight && !RTHEAPSIMPLEBLOCK_IS_FREE(&pRight->Core))
665	{
666	ASSERT_BLOCK(pHeapInt, &pRight->Core);
667	pRight = (PRTHEAPSIMPLEFREE)pRight->Core.pNext;
668	}
669	if (!pRight)
670	pLeft = pHeapInt->pFreeTail;
671	else
672	{
673	ASSERT_BLOCK_FREE(pHeapInt, pRight);
674	pLeft = pRight->pPrev;
675	}
676	if (pLeft)
677	ASSERT_BLOCK_FREE(pHeapInt, pLeft);
678	}
679	AssertMsgReturnVoid(pLeft != pFree, ("Freed twice! pv=%p (pBlock=%p)\n", pBlock + 1, pBlock));
680	ASSERT_L(pLeft, pFree);
681	Assert(!pRight \|\| (uintptr_t)pRight > (uintptr_t)pFree);
682	Assert(!pLeft \|\| pLeft->pNext == pRight);
683
684	/*
685	* Insert at the head of the free block list?
686	*/
687	if (!pLeft)
688	{
689	Assert(pRight == pHeapInt->pFreeHead);
690	pFree->Core.fFlags \|= RTHEAPSIMPLEBLOCK_FLAGS_FREE;
691	pFree->pPrev = NULL;
692	pFree->pNext = pRight;
693	if (pRight)
694	pRight->pPrev = pFree;
695	else
696	pHeapInt->pFreeTail = pFree;
697	pHeapInt->pFreeHead = pFree;
698	}
699	else
700	{
701	/*
702	* Can we merge with left hand free block?
703	*/
704	if (pLeft->Core.pNext == &pFree->Core)
705	{
706	pLeft->Core.pNext = pFree->Core.pNext;
707	if (pFree->Core.pNext)
708	pFree->Core.pNext->pPrev = &pLeft->Core;
709	pHeapInt->cbFree -= pLeft->cb;
710	pFree = pLeft;
711	}
712	/*
713	* No, just link it into the free list then.
714	*/
715	else
716	{
717	pFree->Core.fFlags \|= RTHEAPSIMPLEBLOCK_FLAGS_FREE;
718	pFree->pNext = pRight;
719	pFree->pPrev = pLeft;
720	pLeft->pNext = pFree;
721	if (pRight)
722	pRight->pPrev = pFree;
723	else
724	pHeapInt->pFreeTail = pFree;
725	}
726	}
727
728	/*
729	* Can we merge with right hand free block?
730	*/
731	if ( pRight
732	&& pRight->Core.pPrev == &pFree->Core)
733	{
734	/* core */
735	pFree->Core.pNext = pRight->Core.pNext;
736	if (pRight->Core.pNext)
737	pRight->Core.pNext->pPrev = &pFree->Core;
738
739	/* free */
740	pFree->pNext = pRight->pNext;
741	if (pRight->pNext)
742	pRight->pNext->pPrev = pFree;
743	else
744	pHeapInt->pFreeTail = pFree;
745	pHeapInt->cbFree -= pRight->cb;
746	}
747
748	/*
749	* Calculate the size and update free stats.
750	*/
751	pFree->cb = (pFree->Core.pNext ? (uintptr_t)pFree->Core.pNext : (uintptr_t)pHeapInt->pvEnd)
752	- (uintptr_t)pFree - sizeof(RTHEAPSIMPLEBLOCK);
753	pHeapInt->cbFree += pFree->cb;
754	ASSERT_BLOCK_FREE(pHeapInt, pFree);
755
756	#ifdef RTHEAPSIMPLE_STRICT
757	rtHeapSimpleAssertAll(pHeapInt);
758	#endif
759	}
760
761
762	#ifdef RTHEAPSIMPLE_STRICT
763	/**
764	* Internal consitency check (relying on assertions).
765	* @param pHeapInt
766	*/
767	static void rtHeapSimpleAssertAll(PRTHEAPSIMPLEINTERNAL pHeapInt)
768	{
769	PRTHEAPSIMPLEFREE pPrev = NULL;
770	PRTHEAPSIMPLEFREE pPrevFree = NULL;
771	PRTHEAPSIMPLEFREE pBlock;
772	for (pBlock = (PRTHEAPSIMPLEFREE)(pHeapInt + 1);
773	pBlock;
774	pBlock = (PRTHEAPSIMPLEFREE)pBlock->Core.pNext)
775	{
776	if (RTHEAPSIMPLEBLOCK_IS_FREE(&pBlock->Core))
777	{
778	ASSERT_BLOCK_FREE(pHeapInt, pBlock);
779	Assert(pBlock->pPrev == pPrevFree);
780	Assert(pPrevFree \|\| pHeapInt->pFreeHead == pBlock);
781	pPrevFree = pBlock;
782	}
783	else
784	ASSERT_BLOCK_USED(pHeapInt, &pBlock->Core);
785	Assert(!pPrev \|\| pPrev == (PRTHEAPSIMPLEFREE)pBlock->Core.pPrev);
786	pPrev = pBlock;
787	}
788	Assert(pHeapInt->pFreeTail == pPrevFree);
789	}
790	#endif
791
792
793	/**
794	* Gets the size of the specified heap block.
795	*
796	* @returns The actual size of the heap block.
797	* @returns 0 if \a pv is NULL or it doesn't point to a valid heap block. An invalid \a pv
798	* can also cause traps or trigger assertions.
799	* @param Heap The heap. This is optional and will only be used for strict assertions.
800	* @param pv The heap block returned by RTHeapSimple
801	*/
802	RTDECL(size_t) RTHeapSimpleSize(RTHEAPSIMPLE Heap, void *pv)
803	{
804	/*
805	* Validate input.
806	*/
807	if (!pv)
808	return 0;
809	AssertPtrReturn(pv, 0);
810	AssertReturn(RT_ALIGN_P(pv, RTHEAPSIMPLE_ALIGNMENT) == pv, 0);
811
812	/*
813	* Get the block and heap. If in strict mode, validate these.
814	*/
815	PRTHEAPSIMPLEBLOCK pBlock = (PRTHEAPSIMPLEBLOCK)pv - 1;
816	PRTHEAPSIMPLEINTERNAL pHeapInt = pBlock->pHeap;
817	ASSERT_BLOCK_USED(pHeapInt, pBlock);
818	ASSERT_ANCHOR(pHeapInt);
819	Assert(pHeapInt == (PRTHEAPSIMPLEINTERNAL)Heap \|\| !Heap);
820
821	/*
822	* Calculate the block size.
823	*/
824	const size_t cbBlock = (pBlock->pNext ? (uintptr_t)pBlock->pNext : (uintptr_t)pHeapInt->pvEnd)
825	- (uintptr_t)pBlock- sizeof(RTHEAPSIMPLEBLOCK);
826	return cbBlock;
827	}
828
829
830	/**
831	* Gets the size of the heap.
832	*
833	* This size includes all the internal heap structures. So, even if the heap is
834	* empty the RTHeapSimpleGetFreeSize() will never reach the heap size returned
835	* by this function.
836	*
837	* @returns The heap size.
838	* @returns 0 if heap was safely detected as being bad.
839	* @param Heap The heap.
840	*/
841	RTDECL(size_t) RTHeapSimpleGetHeapSize(RTHEAPSIMPLE Heap)
842	{
843	if (Heap == NIL_RTHEAPSIMPLE)
844	return 0;
845	PRTHEAPSIMPLEINTERNAL pHeapInt = Heap;
846	AssertPtrReturn(pHeapInt, 0);
847	ASSERT_ANCHOR(pHeapInt);
848	return pHeapInt->cbHeap;
849	}
850
851
852	/**
853	* Returns the sum of all free heap blocks.
854	*
855	* This is the amount of memory you can theoretically allocate
856	* if you do allocations exactly matching the free blocks.
857	*
858	* @returns The size of the free blocks.
859	* @returns 0 if heap was safely detected as being bad.
860	* @param Heap The heap.
861	*/
862	RTDECL(size_t) RTHeapSimpleGetFreeSize(RTHEAPSIMPLE Heap)
863	{
864	if (Heap == NIL_RTHEAPSIMPLE)
865	return 0;
866	PRTHEAPSIMPLEINTERNAL pHeapInt = Heap;
867	AssertPtrReturn(pHeapInt, 0);
868	ASSERT_ANCHOR(pHeapInt);
869	return pHeapInt->cbFree;
870	}
871
872
873	/**
874	* Dumps the hypervisor heap.
875	*
876	* @param Heap The heap handle.
877	* @param pfnPrintf Printf like function that groks IPRT formatting.
878	*/
879	RTDECL(void) RTHeapSimpleDump(RTHEAPSIMPLE Heap, PFNRTHEAPSIMPLEPRINTF pfnPrintf)
880	{
881	PRTHEAPSIMPLEINTERNAL pHeapInt = (PRTHEAPSIMPLEINTERNAL)Heap;
882	pfnPrintf("** Dumping Heap %p - cbHeap=%zx cbFree=%zx **\n",
883	Heap, pHeapInt->cbHeap, pHeapInt->cbFree);
884
885	PRTHEAPSIMPLEFREE pBlock;
886	for (pBlock = (PRTHEAPSIMPLEFREE)(pHeapInt + 1);
887	pBlock;
888	pBlock = (PRTHEAPSIMPLEFREE)pBlock->Core.pNext)
889	{
890	size_t cb = (pBlock->pNext ? (uintptr_t)pBlock->Core.pNext : (uintptr_t)pHeapInt->pvEnd)
891	- (uintptr_t)pBlock - sizeof(RTHEAPSIMPLEBLOCK);
892	if (RTHEAPSIMPLEBLOCK_IS_FREE(&pBlock->Core))
893	pfnPrintf("%p %06x FREE pNext=%p pPrev=%p fFlags=%#x cb=%#06x : cb=%#06x pNext=%p pPrev=%p\n",
894	pBlock, (uintptr_t)pBlock - (uintptr_t)(pHeapInt + 1), pBlock->Core.pNext, pBlock->Core.pPrev, pBlock->Core.fFlags, cb,
895	pBlock->cb, pBlock->pNext, pBlock->pPrev);
896	else
897	pfnPrintf("%p %06x USED pNext=%p pPrev=%p fFlags=%#x cb=%#06x\n",
898	pBlock, (uintptr_t)pBlock - (uintptr_t)(pHeapInt + 1), pBlock->Core.pNext, pBlock->Core.pPrev, pBlock->Core.fFlags, cb);
899	}
900	pfnPrintf("** Done dumping Heap %p **\n", Heap);
901	}
902

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source: vbox/trunk/src/VBox/Runtime/alloc/heapsimple.cpp@ 1816

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