xref: /openbmc/u-boot/common/dlmalloc.c (revision 226b50bb)
1 #include <common.h>
2 
3 #if defined(CONFIG_UNIT_TEST)
4 #define DEBUG
5 #endif
6 
7 #include <malloc.h>
8 #include <asm/io.h>
9 
10 #ifdef DEBUG
11 #if __STD_C
12 static void malloc_update_mallinfo (void);
13 void malloc_stats (void);
14 #else
15 static void malloc_update_mallinfo ();
16 void malloc_stats();
17 #endif
18 #endif	/* DEBUG */
19 
20 DECLARE_GLOBAL_DATA_PTR;
21 
22 /*
23   Emulation of sbrk for WIN32
24   All code within the ifdef WIN32 is untested by me.
25 
26   Thanks to Martin Fong and others for supplying this.
27 */
28 
29 
30 #ifdef WIN32
31 
32 #define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \
33 ~(malloc_getpagesize-1))
34 #define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 1))
35 
36 /* resrve 64MB to insure large contiguous space */
37 #define RESERVED_SIZE (1024*1024*64)
38 #define NEXT_SIZE (2048*1024)
39 #define TOP_MEMORY ((unsigned long)2*1024*1024*1024)
40 
41 struct GmListElement;
42 typedef struct GmListElement GmListElement;
43 
44 struct GmListElement
45 {
46 	GmListElement* next;
47 	void* base;
48 };
49 
50 static GmListElement* head = 0;
51 static unsigned int gNextAddress = 0;
52 static unsigned int gAddressBase = 0;
53 static unsigned int gAllocatedSize = 0;
54 
55 static
56 GmListElement* makeGmListElement (void* bas)
57 {
58 	GmListElement* this;
59 	this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement));
60 	assert (this);
61 	if (this)
62 	{
63 		this->base = bas;
64 		this->next = head;
65 		head = this;
66 	}
67 	return this;
68 }
69 
70 void gcleanup ()
71 {
72 	BOOL rval;
73 	assert ( (head == NULL) || (head->base == (void*)gAddressBase));
74 	if (gAddressBase && (gNextAddress - gAddressBase))
75 	{
76 		rval = VirtualFree ((void*)gAddressBase,
77 							gNextAddress - gAddressBase,
78 							MEM_DECOMMIT);
79 	assert (rval);
80 	}
81 	while (head)
82 	{
83 		GmListElement* next = head->next;
84 		rval = VirtualFree (head->base, 0, MEM_RELEASE);
85 		assert (rval);
86 		LocalFree (head);
87 		head = next;
88 	}
89 }
90 
91 static
92 void* findRegion (void* start_address, unsigned long size)
93 {
94 	MEMORY_BASIC_INFORMATION info;
95 	if (size >= TOP_MEMORY) return NULL;
96 
97 	while ((unsigned long)start_address + size < TOP_MEMORY)
98 	{
99 		VirtualQuery (start_address, &info, sizeof (info));
100 		if ((info.State == MEM_FREE) && (info.RegionSize >= size))
101 			return start_address;
102 		else
103 		{
104 			/* Requested region is not available so see if the */
105 			/* next region is available.  Set 'start_address' */
106 			/* to the next region and call 'VirtualQuery()' */
107 			/* again. */
108 
109 			start_address = (char*)info.BaseAddress + info.RegionSize;
110 
111 			/* Make sure we start looking for the next region */
112 			/* on the *next* 64K boundary.  Otherwise, even if */
113 			/* the new region is free according to */
114 			/* 'VirtualQuery()', the subsequent call to */
115 			/* 'VirtualAlloc()' (which follows the call to */
116 			/* this routine in 'wsbrk()') will round *down* */
117 			/* the requested address to a 64K boundary which */
118 			/* we already know is an address in the */
119 			/* unavailable region.  Thus, the subsequent call */
120 			/* to 'VirtualAlloc()' will fail and bring us back */
121 			/* here, causing us to go into an infinite loop. */
122 
123 			start_address =
124 				(void *) AlignPage64K((unsigned long) start_address);
125 		}
126 	}
127 	return NULL;
128 
129 }
130 
131 
132 void* wsbrk (long size)
133 {
134 	void* tmp;
135 	if (size > 0)
136 	{
137 		if (gAddressBase == 0)
138 		{
139 			gAllocatedSize = max (RESERVED_SIZE, AlignPage (size));
140 			gNextAddress = gAddressBase =
141 				(unsigned int)VirtualAlloc (NULL, gAllocatedSize,
142 											MEM_RESERVE, PAGE_NOACCESS);
143 		} else if (AlignPage (gNextAddress + size) > (gAddressBase +
144 gAllocatedSize))
145 		{
146 			long new_size = max (NEXT_SIZE, AlignPage (size));
147 			void* new_address = (void*)(gAddressBase+gAllocatedSize);
148 			do
149 			{
150 				new_address = findRegion (new_address, new_size);
151 
152 				if (new_address == 0)
153 					return (void*)-1;
154 
155 				gAddressBase = gNextAddress =
156 					(unsigned int)VirtualAlloc (new_address, new_size,
157 												MEM_RESERVE, PAGE_NOACCESS);
158 				/* repeat in case of race condition */
159 				/* The region that we found has been snagged */
160 				/* by another thread */
161 			}
162 			while (gAddressBase == 0);
163 
164 			assert (new_address == (void*)gAddressBase);
165 
166 			gAllocatedSize = new_size;
167 
168 			if (!makeGmListElement ((void*)gAddressBase))
169 				return (void*)-1;
170 		}
171 		if ((size + gNextAddress) > AlignPage (gNextAddress))
172 		{
173 			void* res;
174 			res = VirtualAlloc ((void*)AlignPage (gNextAddress),
175 								(size + gNextAddress -
176 								 AlignPage (gNextAddress)),
177 								MEM_COMMIT, PAGE_READWRITE);
178 			if (res == 0)
179 				return (void*)-1;
180 		}
181 		tmp = (void*)gNextAddress;
182 		gNextAddress = (unsigned int)tmp + size;
183 		return tmp;
184 	}
185 	else if (size < 0)
186 	{
187 		unsigned int alignedGoal = AlignPage (gNextAddress + size);
188 		/* Trim by releasing the virtual memory */
189 		if (alignedGoal >= gAddressBase)
190 		{
191 			VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal,
192 						 MEM_DECOMMIT);
193 			gNextAddress = gNextAddress + size;
194 			return (void*)gNextAddress;
195 		}
196 		else
197 		{
198 			VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase,
199 						 MEM_DECOMMIT);
200 			gNextAddress = gAddressBase;
201 			return (void*)-1;
202 		}
203 	}
204 	else
205 	{
206 		return (void*)gNextAddress;
207 	}
208 }
209 
210 #endif
211 
212 
213 
214 /*
215   Type declarations
216 */
217 
218 
219 struct malloc_chunk
220 {
221   INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */
222   INTERNAL_SIZE_T size;      /* Size in bytes, including overhead. */
223   struct malloc_chunk* fd;   /* double links -- used only if free. */
224   struct malloc_chunk* bk;
225 } __attribute__((__may_alias__)) ;
226 
227 typedef struct malloc_chunk* mchunkptr;
228 
229 /*
230 
231    malloc_chunk details:
232 
233     (The following includes lightly edited explanations by Colin Plumb.)
234 
235     Chunks of memory are maintained using a `boundary tag' method as
236     described in e.g., Knuth or Standish.  (See the paper by Paul
237     Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
238     survey of such techniques.)  Sizes of free chunks are stored both
239     in the front of each chunk and at the end.  This makes
240     consolidating fragmented chunks into bigger chunks very fast.  The
241     size fields also hold bits representing whether chunks are free or
242     in use.
243 
244     An allocated chunk looks like this:
245 
246 
247     chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
248 	    |             Size of previous chunk, if allocated            | |
249 	    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
250 	    |             Size of chunk, in bytes                         |P|
251       mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
252 	    |             User data starts here...                          .
253 	    .                                                               .
254 	    .             (malloc_usable_space() bytes)                     .
255 	    .                                                               |
256 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
257 	    |             Size of chunk                                     |
258 	    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
259 
260 
261     Where "chunk" is the front of the chunk for the purpose of most of
262     the malloc code, but "mem" is the pointer that is returned to the
263     user.  "Nextchunk" is the beginning of the next contiguous chunk.
264 
265     Chunks always begin on even word boundries, so the mem portion
266     (which is returned to the user) is also on an even word boundary, and
267     thus double-word aligned.
268 
269     Free chunks are stored in circular doubly-linked lists, and look like this:
270 
271     chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
272 	    |             Size of previous chunk                            |
273 	    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
274     `head:' |             Size of chunk, in bytes                         |P|
275       mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
276 	    |             Forward pointer to next chunk in list             |
277 	    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
278 	    |             Back pointer to previous chunk in list            |
279 	    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
280 	    |             Unused space (may be 0 bytes long)                .
281 	    .                                                               .
282 	    .                                                               |
283 nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
284     `foot:' |             Size of chunk, in bytes                           |
285 	    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
286 
287     The P (PREV_INUSE) bit, stored in the unused low-order bit of the
288     chunk size (which is always a multiple of two words), is an in-use
289     bit for the *previous* chunk.  If that bit is *clear*, then the
290     word before the current chunk size contains the previous chunk
291     size, and can be used to find the front of the previous chunk.
292     (The very first chunk allocated always has this bit set,
293     preventing access to non-existent (or non-owned) memory.)
294 
295     Note that the `foot' of the current chunk is actually represented
296     as the prev_size of the NEXT chunk. (This makes it easier to
297     deal with alignments etc).
298 
299     The two exceptions to all this are
300 
301      1. The special chunk `top', which doesn't bother using the
302 	trailing size field since there is no
303 	next contiguous chunk that would have to index off it. (After
304 	initialization, `top' is forced to always exist.  If it would
305 	become less than MINSIZE bytes long, it is replenished via
306 	malloc_extend_top.)
307 
308      2. Chunks allocated via mmap, which have the second-lowest-order
309 	bit (IS_MMAPPED) set in their size fields.  Because they are
310 	never merged or traversed from any other chunk, they have no
311 	foot size or inuse information.
312 
313     Available chunks are kept in any of several places (all declared below):
314 
315     * `av': An array of chunks serving as bin headers for consolidated
316        chunks. Each bin is doubly linked.  The bins are approximately
317        proportionally (log) spaced.  There are a lot of these bins
318        (128). This may look excessive, but works very well in
319        practice.  All procedures maintain the invariant that no
320        consolidated chunk physically borders another one. Chunks in
321        bins are kept in size order, with ties going to the
322        approximately least recently used chunk.
323 
324        The chunks in each bin are maintained in decreasing sorted order by
325        size.  This is irrelevant for the small bins, which all contain
326        the same-sized chunks, but facilitates best-fit allocation for
327        larger chunks. (These lists are just sequential. Keeping them in
328        order almost never requires enough traversal to warrant using
329        fancier ordered data structures.)  Chunks of the same size are
330        linked with the most recently freed at the front, and allocations
331        are taken from the back.  This results in LRU or FIFO allocation
332        order, which tends to give each chunk an equal opportunity to be
333        consolidated with adjacent freed chunks, resulting in larger free
334        chunks and less fragmentation.
335 
336     * `top': The top-most available chunk (i.e., the one bordering the
337        end of available memory) is treated specially. It is never
338        included in any bin, is used only if no other chunk is
339        available, and is released back to the system if it is very
340        large (see M_TRIM_THRESHOLD).
341 
342     * `last_remainder': A bin holding only the remainder of the
343        most recently split (non-top) chunk. This bin is checked
344        before other non-fitting chunks, so as to provide better
345        locality for runs of sequentially allocated chunks.
346 
347     *  Implicitly, through the host system's memory mapping tables.
348        If supported, requests greater than a threshold are usually
349        serviced via calls to mmap, and then later released via munmap.
350 
351 */
352 
353 /*  sizes, alignments */
354 
355 #define SIZE_SZ                (sizeof(INTERNAL_SIZE_T))
356 #define MALLOC_ALIGNMENT       (SIZE_SZ + SIZE_SZ)
357 #define MALLOC_ALIGN_MASK      (MALLOC_ALIGNMENT - 1)
358 #define MINSIZE                (sizeof(struct malloc_chunk))
359 
360 /* conversion from malloc headers to user pointers, and back */
361 
362 #define chunk2mem(p)   ((Void_t*)((char*)(p) + 2*SIZE_SZ))
363 #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
364 
365 /* pad request bytes into a usable size */
366 
367 #define request2size(req) \
368  (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
369   (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
370    (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
371 
372 /* Check if m has acceptable alignment */
373 
374 #define aligned_OK(m)    (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
375 
376 
377 
378 
379 /*
380   Physical chunk operations
381 */
382 
383 
384 /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
385 
386 #define PREV_INUSE 0x1
387 
388 /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
389 
390 #define IS_MMAPPED 0x2
391 
392 /* Bits to mask off when extracting size */
393 
394 #define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
395 
396 
397 /* Ptr to next physical malloc_chunk. */
398 
399 #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))
400 
401 /* Ptr to previous physical malloc_chunk */
402 
403 #define prev_chunk(p)\
404    ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
405 
406 
407 /* Treat space at ptr + offset as a chunk */
408 
409 #define chunk_at_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
410 
411 
412 
413 
414 /*
415   Dealing with use bits
416 */
417 
418 /* extract p's inuse bit */
419 
420 #define inuse(p)\
421 ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)
422 
423 /* extract inuse bit of previous chunk */
424 
425 #define prev_inuse(p)  ((p)->size & PREV_INUSE)
426 
427 /* check for mmap()'ed chunk */
428 
429 #define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
430 
431 /* set/clear chunk as in use without otherwise disturbing */
432 
433 #define set_inuse(p)\
434 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE
435 
436 #define clear_inuse(p)\
437 ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)
438 
439 /* check/set/clear inuse bits in known places */
440 
441 #define inuse_bit_at_offset(p, s)\
442  (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
443 
444 #define set_inuse_bit_at_offset(p, s)\
445  (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
446 
447 #define clear_inuse_bit_at_offset(p, s)\
448  (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
449 
450 
451 
452 
453 /*
454   Dealing with size fields
455 */
456 
457 /* Get size, ignoring use bits */
458 
459 #define chunksize(p)          ((p)->size & ~(SIZE_BITS))
460 
461 /* Set size at head, without disturbing its use bit */
462 
463 #define set_head_size(p, s)   ((p)->size = (((p)->size & PREV_INUSE) | (s)))
464 
465 /* Set size/use ignoring previous bits in header */
466 
467 #define set_head(p, s)        ((p)->size = (s))
468 
469 /* Set size at footer (only when chunk is not in use) */
470 
471 #define set_foot(p, s)   (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
472 
473 
474 
475 
476 
477 /*
478    Bins
479 
480     The bins, `av_' are an array of pairs of pointers serving as the
481     heads of (initially empty) doubly-linked lists of chunks, laid out
482     in a way so that each pair can be treated as if it were in a
483     malloc_chunk. (This way, the fd/bk offsets for linking bin heads
484     and chunks are the same).
485 
486     Bins for sizes < 512 bytes contain chunks of all the same size, spaced
487     8 bytes apart. Larger bins are approximately logarithmically
488     spaced. (See the table below.) The `av_' array is never mentioned
489     directly in the code, but instead via bin access macros.
490 
491     Bin layout:
492 
493     64 bins of size       8
494     32 bins of size      64
495     16 bins of size     512
496      8 bins of size    4096
497      4 bins of size   32768
498      2 bins of size  262144
499      1 bin  of size what's left
500 
501     There is actually a little bit of slop in the numbers in bin_index
502     for the sake of speed. This makes no difference elsewhere.
503 
504     The special chunks `top' and `last_remainder' get their own bins,
505     (this is implemented via yet more trickery with the av_ array),
506     although `top' is never properly linked to its bin since it is
507     always handled specially.
508 
509 */
510 
511 #define NAV             128   /* number of bins */
512 
513 typedef struct malloc_chunk* mbinptr;
514 
515 /* access macros */
516 
517 #define bin_at(i)      ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
518 #define next_bin(b)    ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
519 #define prev_bin(b)    ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))
520 
521 /*
522    The first 2 bins are never indexed. The corresponding av_ cells are instead
523    used for bookkeeping. This is not to save space, but to simplify
524    indexing, maintain locality, and avoid some initialization tests.
525 */
526 
527 #define top            (av_[2])          /* The topmost chunk */
528 #define last_remainder (bin_at(1))       /* remainder from last split */
529 
530 
531 /*
532    Because top initially points to its own bin with initial
533    zero size, thus forcing extension on the first malloc request,
534    we avoid having any special code in malloc to check whether
535    it even exists yet. But we still need to in malloc_extend_top.
536 */
537 
538 #define initial_top    ((mchunkptr)(bin_at(0)))
539 
540 /* Helper macro to initialize bins */
541 
542 #define IAV(i)  bin_at(i), bin_at(i)
543 
544 static mbinptr av_[NAV * 2 + 2] = {
545  NULL, NULL,
546  IAV(0),   IAV(1),   IAV(2),   IAV(3),   IAV(4),   IAV(5),   IAV(6),   IAV(7),
547  IAV(8),   IAV(9),   IAV(10),  IAV(11),  IAV(12),  IAV(13),  IAV(14),  IAV(15),
548  IAV(16),  IAV(17),  IAV(18),  IAV(19),  IAV(20),  IAV(21),  IAV(22),  IAV(23),
549  IAV(24),  IAV(25),  IAV(26),  IAV(27),  IAV(28),  IAV(29),  IAV(30),  IAV(31),
550  IAV(32),  IAV(33),  IAV(34),  IAV(35),  IAV(36),  IAV(37),  IAV(38),  IAV(39),
551  IAV(40),  IAV(41),  IAV(42),  IAV(43),  IAV(44),  IAV(45),  IAV(46),  IAV(47),
552  IAV(48),  IAV(49),  IAV(50),  IAV(51),  IAV(52),  IAV(53),  IAV(54),  IAV(55),
553  IAV(56),  IAV(57),  IAV(58),  IAV(59),  IAV(60),  IAV(61),  IAV(62),  IAV(63),
554  IAV(64),  IAV(65),  IAV(66),  IAV(67),  IAV(68),  IAV(69),  IAV(70),  IAV(71),
555  IAV(72),  IAV(73),  IAV(74),  IAV(75),  IAV(76),  IAV(77),  IAV(78),  IAV(79),
556  IAV(80),  IAV(81),  IAV(82),  IAV(83),  IAV(84),  IAV(85),  IAV(86),  IAV(87),
557  IAV(88),  IAV(89),  IAV(90),  IAV(91),  IAV(92),  IAV(93),  IAV(94),  IAV(95),
558  IAV(96),  IAV(97),  IAV(98),  IAV(99),  IAV(100), IAV(101), IAV(102), IAV(103),
559  IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
560  IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
561  IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
562 };
563 
564 #ifdef CONFIG_NEEDS_MANUAL_RELOC
565 static void malloc_bin_reloc(void)
566 {
567 	mbinptr *p = &av_[2];
568 	size_t i;
569 
570 	for (i = 2; i < ARRAY_SIZE(av_); ++i, ++p)
571 		*p = (mbinptr)((ulong)*p + gd->reloc_off);
572 }
573 #else
574 static inline void malloc_bin_reloc(void) {}
575 #endif
576 
577 ulong mem_malloc_start = 0;
578 ulong mem_malloc_end = 0;
579 ulong mem_malloc_brk = 0;
580 
581 void *sbrk(ptrdiff_t increment)
582 {
583 	ulong old = mem_malloc_brk;
584 	ulong new = old + increment;
585 
586 	/*
587 	 * if we are giving memory back make sure we clear it out since
588 	 * we set MORECORE_CLEARS to 1
589 	 */
590 	if (increment < 0)
591 		memset((void *)new, 0, -increment);
592 
593 	if ((new < mem_malloc_start) || (new > mem_malloc_end))
594 		return (void *)MORECORE_FAILURE;
595 
596 	mem_malloc_brk = new;
597 
598 	return (void *)old;
599 }
600 
601 void mem_malloc_init(ulong start, ulong size)
602 {
603 	mem_malloc_start = start;
604 	mem_malloc_end = start + size;
605 	mem_malloc_brk = start;
606 
607 	debug("using memory %#lx-%#lx for malloc()\n", mem_malloc_start,
608 	      mem_malloc_end);
609 #ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
610 	memset((void *)mem_malloc_start, 0x0, size);
611 #endif
612 	malloc_bin_reloc();
613 }
614 
615 /* field-extraction macros */
616 
617 #define first(b) ((b)->fd)
618 #define last(b)  ((b)->bk)
619 
620 /*
621   Indexing into bins
622 */
623 
624 #define bin_index(sz)                                                          \
625 (((((unsigned long)(sz)) >> 9) ==    0) ?       (((unsigned long)(sz)) >>  3): \
626  ((((unsigned long)(sz)) >> 9) <=    4) ?  56 + (((unsigned long)(sz)) >>  6): \
627  ((((unsigned long)(sz)) >> 9) <=   20) ?  91 + (((unsigned long)(sz)) >>  9): \
628  ((((unsigned long)(sz)) >> 9) <=   84) ? 110 + (((unsigned long)(sz)) >> 12): \
629  ((((unsigned long)(sz)) >> 9) <=  340) ? 119 + (((unsigned long)(sz)) >> 15): \
630  ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
631 					  126)
632 /*
633   bins for chunks < 512 are all spaced 8 bytes apart, and hold
634   identically sized chunks. This is exploited in malloc.
635 */
636 
637 #define MAX_SMALLBIN         63
638 #define MAX_SMALLBIN_SIZE   512
639 #define SMALLBIN_WIDTH        8
640 
641 #define smallbin_index(sz)  (((unsigned long)(sz)) >> 3)
642 
643 /*
644    Requests are `small' if both the corresponding and the next bin are small
645 */
646 
647 #define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)
648 
649 
650 
651 /*
652     To help compensate for the large number of bins, a one-level index
653     structure is used for bin-by-bin searching.  `binblocks' is a
654     one-word bitvector recording whether groups of BINBLOCKWIDTH bins
655     have any (possibly) non-empty bins, so they can be skipped over
656     all at once during during traversals. The bits are NOT always
657     cleared as soon as all bins in a block are empty, but instead only
658     when all are noticed to be empty during traversal in malloc.
659 */
660 
661 #define BINBLOCKWIDTH     4   /* bins per block */
662 
663 #define binblocks_r     ((INTERNAL_SIZE_T)av_[1]) /* bitvector of nonempty blocks */
664 #define binblocks_w     (av_[1])
665 
666 /* bin<->block macros */
667 
668 #define idx2binblock(ix)    ((unsigned)1 << (ix / BINBLOCKWIDTH))
669 #define mark_binblock(ii)   (binblocks_w = (mbinptr)(binblocks_r | idx2binblock(ii)))
670 #define clear_binblock(ii)  (binblocks_w = (mbinptr)(binblocks_r & ~(idx2binblock(ii))))
671 
672 
673 
674 
675 
676 /*  Other static bookkeeping data */
677 
678 /* variables holding tunable values */
679 
680 static unsigned long trim_threshold   = DEFAULT_TRIM_THRESHOLD;
681 static unsigned long top_pad          = DEFAULT_TOP_PAD;
682 static unsigned int  n_mmaps_max      = DEFAULT_MMAP_MAX;
683 static unsigned long mmap_threshold   = DEFAULT_MMAP_THRESHOLD;
684 
685 /* The first value returned from sbrk */
686 static char* sbrk_base = (char*)(-1);
687 
688 /* The maximum memory obtained from system via sbrk */
689 static unsigned long max_sbrked_mem = 0;
690 
691 /* The maximum via either sbrk or mmap */
692 static unsigned long max_total_mem = 0;
693 
694 /* internal working copy of mallinfo */
695 static struct mallinfo current_mallinfo = {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
696 
697 /* The total memory obtained from system via sbrk */
698 #define sbrked_mem  (current_mallinfo.arena)
699 
700 /* Tracking mmaps */
701 
702 #ifdef DEBUG
703 static unsigned int n_mmaps = 0;
704 #endif	/* DEBUG */
705 static unsigned long mmapped_mem = 0;
706 #if HAVE_MMAP
707 static unsigned int max_n_mmaps = 0;
708 static unsigned long max_mmapped_mem = 0;
709 #endif
710 
711 
712 
713 /*
714   Debugging support
715 */
716 
717 #ifdef DEBUG
718 
719 
720 /*
721   These routines make a number of assertions about the states
722   of data structures that should be true at all times. If any
723   are not true, it's very likely that a user program has somehow
724   trashed memory. (It's also possible that there is a coding error
725   in malloc. In which case, please report it!)
726 */
727 
728 #if __STD_C
729 static void do_check_chunk(mchunkptr p)
730 #else
731 static void do_check_chunk(p) mchunkptr p;
732 #endif
733 {
734   INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
735 
736   /* No checkable chunk is mmapped */
737   assert(!chunk_is_mmapped(p));
738 
739   /* Check for legal address ... */
740   assert((char*)p >= sbrk_base);
741   if (p != top)
742     assert((char*)p + sz <= (char*)top);
743   else
744     assert((char*)p + sz <= sbrk_base + sbrked_mem);
745 
746 }
747 
748 
749 #if __STD_C
750 static void do_check_free_chunk(mchunkptr p)
751 #else
752 static void do_check_free_chunk(p) mchunkptr p;
753 #endif
754 {
755   INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
756   mchunkptr next = chunk_at_offset(p, sz);
757 
758   do_check_chunk(p);
759 
760   /* Check whether it claims to be free ... */
761   assert(!inuse(p));
762 
763   /* Unless a special marker, must have OK fields */
764   if ((long)sz >= (long)MINSIZE)
765   {
766     assert((sz & MALLOC_ALIGN_MASK) == 0);
767     assert(aligned_OK(chunk2mem(p)));
768     /* ... matching footer field */
769     assert(next->prev_size == sz);
770     /* ... and is fully consolidated */
771     assert(prev_inuse(p));
772     assert (next == top || inuse(next));
773 
774     /* ... and has minimally sane links */
775     assert(p->fd->bk == p);
776     assert(p->bk->fd == p);
777   }
778   else /* markers are always of size SIZE_SZ */
779     assert(sz == SIZE_SZ);
780 }
781 
782 #if __STD_C
783 static void do_check_inuse_chunk(mchunkptr p)
784 #else
785 static void do_check_inuse_chunk(p) mchunkptr p;
786 #endif
787 {
788   mchunkptr next = next_chunk(p);
789   do_check_chunk(p);
790 
791   /* Check whether it claims to be in use ... */
792   assert(inuse(p));
793 
794   /* ... and is surrounded by OK chunks.
795     Since more things can be checked with free chunks than inuse ones,
796     if an inuse chunk borders them and debug is on, it's worth doing them.
797   */
798   if (!prev_inuse(p))
799   {
800     mchunkptr prv = prev_chunk(p);
801     assert(next_chunk(prv) == p);
802     do_check_free_chunk(prv);
803   }
804   if (next == top)
805   {
806     assert(prev_inuse(next));
807     assert(chunksize(next) >= MINSIZE);
808   }
809   else if (!inuse(next))
810     do_check_free_chunk(next);
811 
812 }
813 
814 #if __STD_C
815 static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
816 #else
817 static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
818 #endif
819 {
820   INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
821   long room = sz - s;
822 
823   do_check_inuse_chunk(p);
824 
825   /* Legal size ... */
826   assert((long)sz >= (long)MINSIZE);
827   assert((sz & MALLOC_ALIGN_MASK) == 0);
828   assert(room >= 0);
829   assert(room < (long)MINSIZE);
830 
831   /* ... and alignment */
832   assert(aligned_OK(chunk2mem(p)));
833 
834 
835   /* ... and was allocated at front of an available chunk */
836   assert(prev_inuse(p));
837 
838 }
839 
840 
841 #define check_free_chunk(P)  do_check_free_chunk(P)
842 #define check_inuse_chunk(P) do_check_inuse_chunk(P)
843 #define check_chunk(P) do_check_chunk(P)
844 #define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N)
845 #else
846 #define check_free_chunk(P)
847 #define check_inuse_chunk(P)
848 #define check_chunk(P)
849 #define check_malloced_chunk(P,N)
850 #endif
851 
852 
853 
854 /*
855   Macro-based internal utilities
856 */
857 
858 
859 /*
860   Linking chunks in bin lists.
861   Call these only with variables, not arbitrary expressions, as arguments.
862 */
863 
864 /*
865   Place chunk p of size s in its bin, in size order,
866   putting it ahead of others of same size.
867 */
868 
869 
870 #define frontlink(P, S, IDX, BK, FD)                                          \
871 {                                                                             \
872   if (S < MAX_SMALLBIN_SIZE)                                                  \
873   {                                                                           \
874     IDX = smallbin_index(S);                                                  \
875     mark_binblock(IDX);                                                       \
876     BK = bin_at(IDX);                                                         \
877     FD = BK->fd;                                                              \
878     P->bk = BK;                                                               \
879     P->fd = FD;                                                               \
880     FD->bk = BK->fd = P;                                                      \
881   }                                                                           \
882   else                                                                        \
883   {                                                                           \
884     IDX = bin_index(S);                                                       \
885     BK = bin_at(IDX);                                                         \
886     FD = BK->fd;                                                              \
887     if (FD == BK) mark_binblock(IDX);                                         \
888     else                                                                      \
889     {                                                                         \
890       while (FD != BK && S < chunksize(FD)) FD = FD->fd;                      \
891       BK = FD->bk;                                                            \
892     }                                                                         \
893     P->bk = BK;                                                               \
894     P->fd = FD;                                                               \
895     FD->bk = BK->fd = P;                                                      \
896   }                                                                           \
897 }
898 
899 
900 /* take a chunk off a list */
901 
902 #define unlink(P, BK, FD)                                                     \
903 {                                                                             \
904   BK = P->bk;                                                                 \
905   FD = P->fd;                                                                 \
906   FD->bk = BK;                                                                \
907   BK->fd = FD;                                                                \
908 }                                                                             \
909 
910 /* Place p as the last remainder */
911 
912 #define link_last_remainder(P)                                                \
913 {                                                                             \
914   last_remainder->fd = last_remainder->bk =  P;                               \
915   P->fd = P->bk = last_remainder;                                             \
916 }
917 
918 /* Clear the last_remainder bin */
919 
920 #define clear_last_remainder \
921   (last_remainder->fd = last_remainder->bk = last_remainder)
922 
923 
924 
925 
926 
927 /* Routines dealing with mmap(). */
928 
929 #if HAVE_MMAP
930 
931 #if __STD_C
932 static mchunkptr mmap_chunk(size_t size)
933 #else
934 static mchunkptr mmap_chunk(size) size_t size;
935 #endif
936 {
937   size_t page_mask = malloc_getpagesize - 1;
938   mchunkptr p;
939 
940 #ifndef MAP_ANONYMOUS
941   static int fd = -1;
942 #endif
943 
944   if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */
945 
946   /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
947    * there is no following chunk whose prev_size field could be used.
948    */
949   size = (size + SIZE_SZ + page_mask) & ~page_mask;
950 
951 #ifdef MAP_ANONYMOUS
952   p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE,
953 		      MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
954 #else /* !MAP_ANONYMOUS */
955   if (fd < 0)
956   {
957     fd = open("/dev/zero", O_RDWR);
958     if(fd < 0) return 0;
959   }
960   p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
961 #endif
962 
963   if(p == (mchunkptr)-1) return 0;
964 
965   n_mmaps++;
966   if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;
967 
968   /* We demand that eight bytes into a page must be 8-byte aligned. */
969   assert(aligned_OK(chunk2mem(p)));
970 
971   /* The offset to the start of the mmapped region is stored
972    * in the prev_size field of the chunk; normally it is zero,
973    * but that can be changed in memalign().
974    */
975   p->prev_size = 0;
976   set_head(p, size|IS_MMAPPED);
977 
978   mmapped_mem += size;
979   if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
980     max_mmapped_mem = mmapped_mem;
981   if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
982     max_total_mem = mmapped_mem + sbrked_mem;
983   return p;
984 }
985 
986 #if __STD_C
987 static void munmap_chunk(mchunkptr p)
988 #else
989 static void munmap_chunk(p) mchunkptr p;
990 #endif
991 {
992   INTERNAL_SIZE_T size = chunksize(p);
993   int ret;
994 
995   assert (chunk_is_mmapped(p));
996   assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
997   assert((n_mmaps > 0));
998   assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);
999 
1000   n_mmaps--;
1001   mmapped_mem -= (size + p->prev_size);
1002 
1003   ret = munmap((char *)p - p->prev_size, size + p->prev_size);
1004 
1005   /* munmap returns non-zero on failure */
1006   assert(ret == 0);
1007 }
1008 
1009 #if HAVE_MREMAP
1010 
1011 #if __STD_C
1012 static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
1013 #else
1014 static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
1015 #endif
1016 {
1017   size_t page_mask = malloc_getpagesize - 1;
1018   INTERNAL_SIZE_T offset = p->prev_size;
1019   INTERNAL_SIZE_T size = chunksize(p);
1020   char *cp;
1021 
1022   assert (chunk_is_mmapped(p));
1023   assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1024   assert((n_mmaps > 0));
1025   assert(((size + offset) & (malloc_getpagesize-1)) == 0);
1026 
1027   /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
1028   new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;
1029 
1030   cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1);
1031 
1032   if (cp == (char *)-1) return 0;
1033 
1034   p = (mchunkptr)(cp + offset);
1035 
1036   assert(aligned_OK(chunk2mem(p)));
1037 
1038   assert((p->prev_size == offset));
1039   set_head(p, (new_size - offset)|IS_MMAPPED);
1040 
1041   mmapped_mem -= size + offset;
1042   mmapped_mem += new_size;
1043   if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1044     max_mmapped_mem = mmapped_mem;
1045   if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1046     max_total_mem = mmapped_mem + sbrked_mem;
1047   return p;
1048 }
1049 
1050 #endif /* HAVE_MREMAP */
1051 
1052 #endif /* HAVE_MMAP */
1053 
1054 
1055 
1056 
1057 /*
1058   Extend the top-most chunk by obtaining memory from system.
1059   Main interface to sbrk (but see also malloc_trim).
1060 */
1061 
1062 #if __STD_C
1063 static void malloc_extend_top(INTERNAL_SIZE_T nb)
1064 #else
1065 static void malloc_extend_top(nb) INTERNAL_SIZE_T nb;
1066 #endif
1067 {
1068   char*     brk;                  /* return value from sbrk */
1069   INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
1070   INTERNAL_SIZE_T correction;     /* bytes for 2nd sbrk call */
1071   char*     new_brk;              /* return of 2nd sbrk call */
1072   INTERNAL_SIZE_T top_size;       /* new size of top chunk */
1073 
1074   mchunkptr old_top     = top;  /* Record state of old top */
1075   INTERNAL_SIZE_T old_top_size = chunksize(old_top);
1076   char*     old_end      = (char*)(chunk_at_offset(old_top, old_top_size));
1077 
1078   /* Pad request with top_pad plus minimal overhead */
1079 
1080   INTERNAL_SIZE_T    sbrk_size     = nb + top_pad + MINSIZE;
1081   unsigned long pagesz    = malloc_getpagesize;
1082 
1083   /* If not the first time through, round to preserve page boundary */
1084   /* Otherwise, we need to correct to a page size below anyway. */
1085   /* (We also correct below if an intervening foreign sbrk call.) */
1086 
1087   if (sbrk_base != (char*)(-1))
1088     sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1);
1089 
1090   brk = (char*)(MORECORE (sbrk_size));
1091 
1092   /* Fail if sbrk failed or if a foreign sbrk call killed our space */
1093   if (brk == (char*)(MORECORE_FAILURE) ||
1094       (brk < old_end && old_top != initial_top))
1095     return;
1096 
1097   sbrked_mem += sbrk_size;
1098 
1099   if (brk == old_end) /* can just add bytes to current top */
1100   {
1101     top_size = sbrk_size + old_top_size;
1102     set_head(top, top_size | PREV_INUSE);
1103   }
1104   else
1105   {
1106     if (sbrk_base == (char*)(-1))  /* First time through. Record base */
1107       sbrk_base = brk;
1108     else  /* Someone else called sbrk().  Count those bytes as sbrked_mem. */
1109       sbrked_mem += brk - (char*)old_end;
1110 
1111     /* Guarantee alignment of first new chunk made from this space */
1112     front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
1113     if (front_misalign > 0)
1114     {
1115       correction = (MALLOC_ALIGNMENT) - front_misalign;
1116       brk += correction;
1117     }
1118     else
1119       correction = 0;
1120 
1121     /* Guarantee the next brk will be at a page boundary */
1122 
1123     correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) &
1124 		   ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size));
1125 
1126     /* Allocate correction */
1127     new_brk = (char*)(MORECORE (correction));
1128     if (new_brk == (char*)(MORECORE_FAILURE)) return;
1129 
1130     sbrked_mem += correction;
1131 
1132     top = (mchunkptr)brk;
1133     top_size = new_brk - brk + correction;
1134     set_head(top, top_size | PREV_INUSE);
1135 
1136     if (old_top != initial_top)
1137     {
1138 
1139       /* There must have been an intervening foreign sbrk call. */
1140       /* A double fencepost is necessary to prevent consolidation */
1141 
1142       /* If not enough space to do this, then user did something very wrong */
1143       if (old_top_size < MINSIZE)
1144       {
1145 	set_head(top, PREV_INUSE); /* will force null return from malloc */
1146 	return;
1147       }
1148 
1149       /* Also keep size a multiple of MALLOC_ALIGNMENT */
1150       old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
1151       set_head_size(old_top, old_top_size);
1152       chunk_at_offset(old_top, old_top_size          )->size =
1153 	SIZE_SZ|PREV_INUSE;
1154       chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size =
1155 	SIZE_SZ|PREV_INUSE;
1156       /* If possible, release the rest. */
1157       if (old_top_size >= MINSIZE)
1158 	fREe(chunk2mem(old_top));
1159     }
1160   }
1161 
1162   if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
1163     max_sbrked_mem = sbrked_mem;
1164   if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1165     max_total_mem = mmapped_mem + sbrked_mem;
1166 
1167   /* We always land on a page boundary */
1168   assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0);
1169 }
1170 
1171 
1172 
1173 
1174 /* Main public routines */
1175 
1176 
1177 /*
1178   Malloc Algorthim:
1179 
1180     The requested size is first converted into a usable form, `nb'.
1181     This currently means to add 4 bytes overhead plus possibly more to
1182     obtain 8-byte alignment and/or to obtain a size of at least
1183     MINSIZE (currently 16 bytes), the smallest allocatable size.
1184     (All fits are considered `exact' if they are within MINSIZE bytes.)
1185 
1186     From there, the first successful of the following steps is taken:
1187 
1188       1. The bin corresponding to the request size is scanned, and if
1189 	 a chunk of exactly the right size is found, it is taken.
1190 
1191       2. The most recently remaindered chunk is used if it is big
1192 	 enough.  This is a form of (roving) first fit, used only in
1193 	 the absence of exact fits. Runs of consecutive requests use
1194 	 the remainder of the chunk used for the previous such request
1195 	 whenever possible. This limited use of a first-fit style
1196 	 allocation strategy tends to give contiguous chunks
1197 	 coextensive lifetimes, which improves locality and can reduce
1198 	 fragmentation in the long run.
1199 
1200       3. Other bins are scanned in increasing size order, using a
1201 	 chunk big enough to fulfill the request, and splitting off
1202 	 any remainder.  This search is strictly by best-fit; i.e.,
1203 	 the smallest (with ties going to approximately the least
1204 	 recently used) chunk that fits is selected.
1205 
1206       4. If large enough, the chunk bordering the end of memory
1207 	 (`top') is split off. (This use of `top' is in accord with
1208 	 the best-fit search rule.  In effect, `top' is treated as
1209 	 larger (and thus less well fitting) than any other available
1210 	 chunk since it can be extended to be as large as necessary
1211 	 (up to system limitations).
1212 
1213       5. If the request size meets the mmap threshold and the
1214 	 system supports mmap, and there are few enough currently
1215 	 allocated mmapped regions, and a call to mmap succeeds,
1216 	 the request is allocated via direct memory mapping.
1217 
1218       6. Otherwise, the top of memory is extended by
1219 	 obtaining more space from the system (normally using sbrk,
1220 	 but definable to anything else via the MORECORE macro).
1221 	 Memory is gathered from the system (in system page-sized
1222 	 units) in a way that allows chunks obtained across different
1223 	 sbrk calls to be consolidated, but does not require
1224 	 contiguous memory. Thus, it should be safe to intersperse
1225 	 mallocs with other sbrk calls.
1226 
1227 
1228       All allocations are made from the the `lowest' part of any found
1229       chunk. (The implementation invariant is that prev_inuse is
1230       always true of any allocated chunk; i.e., that each allocated
1231       chunk borders either a previously allocated and still in-use chunk,
1232       or the base of its memory arena.)
1233 
1234 */
1235 
1236 #if __STD_C
1237 Void_t* mALLOc(size_t bytes)
1238 #else
1239 Void_t* mALLOc(bytes) size_t bytes;
1240 #endif
1241 {
1242   mchunkptr victim;                  /* inspected/selected chunk */
1243   INTERNAL_SIZE_T victim_size;       /* its size */
1244   int       idx;                     /* index for bin traversal */
1245   mbinptr   bin;                     /* associated bin */
1246   mchunkptr remainder;               /* remainder from a split */
1247   long      remainder_size;          /* its size */
1248   int       remainder_index;         /* its bin index */
1249   unsigned long block;               /* block traverser bit */
1250   int       startidx;                /* first bin of a traversed block */
1251   mchunkptr fwd;                     /* misc temp for linking */
1252   mchunkptr bck;                     /* misc temp for linking */
1253   mbinptr q;                         /* misc temp */
1254 
1255   INTERNAL_SIZE_T nb;
1256 
1257 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1258 	if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT))
1259 		return malloc_simple(bytes);
1260 #endif
1261 
1262   /* check if mem_malloc_init() was run */
1263   if ((mem_malloc_start == 0) && (mem_malloc_end == 0)) {
1264     /* not initialized yet */
1265     return NULL;
1266   }
1267 
1268   if ((long)bytes < 0) return NULL;
1269 
1270   nb = request2size(bytes);  /* padded request size; */
1271 
1272   /* Check for exact match in a bin */
1273 
1274   if (is_small_request(nb))  /* Faster version for small requests */
1275   {
1276     idx = smallbin_index(nb);
1277 
1278     /* No traversal or size check necessary for small bins.  */
1279 
1280     q = bin_at(idx);
1281     victim = last(q);
1282 
1283     /* Also scan the next one, since it would have a remainder < MINSIZE */
1284     if (victim == q)
1285     {
1286       q = next_bin(q);
1287       victim = last(q);
1288     }
1289     if (victim != q)
1290     {
1291       victim_size = chunksize(victim);
1292       unlink(victim, bck, fwd);
1293       set_inuse_bit_at_offset(victim, victim_size);
1294       check_malloced_chunk(victim, nb);
1295       return chunk2mem(victim);
1296     }
1297 
1298     idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */
1299 
1300   }
1301   else
1302   {
1303     idx = bin_index(nb);
1304     bin = bin_at(idx);
1305 
1306     for (victim = last(bin); victim != bin; victim = victim->bk)
1307     {
1308       victim_size = chunksize(victim);
1309       remainder_size = victim_size - nb;
1310 
1311       if (remainder_size >= (long)MINSIZE) /* too big */
1312       {
1313 	--idx; /* adjust to rescan below after checking last remainder */
1314 	break;
1315       }
1316 
1317       else if (remainder_size >= 0) /* exact fit */
1318       {
1319 	unlink(victim, bck, fwd);
1320 	set_inuse_bit_at_offset(victim, victim_size);
1321 	check_malloced_chunk(victim, nb);
1322 	return chunk2mem(victim);
1323       }
1324     }
1325 
1326     ++idx;
1327 
1328   }
1329 
1330   /* Try to use the last split-off remainder */
1331 
1332   if ( (victim = last_remainder->fd) != last_remainder)
1333   {
1334     victim_size = chunksize(victim);
1335     remainder_size = victim_size - nb;
1336 
1337     if (remainder_size >= (long)MINSIZE) /* re-split */
1338     {
1339       remainder = chunk_at_offset(victim, nb);
1340       set_head(victim, nb | PREV_INUSE);
1341       link_last_remainder(remainder);
1342       set_head(remainder, remainder_size | PREV_INUSE);
1343       set_foot(remainder, remainder_size);
1344       check_malloced_chunk(victim, nb);
1345       return chunk2mem(victim);
1346     }
1347 
1348     clear_last_remainder;
1349 
1350     if (remainder_size >= 0)  /* exhaust */
1351     {
1352       set_inuse_bit_at_offset(victim, victim_size);
1353       check_malloced_chunk(victim, nb);
1354       return chunk2mem(victim);
1355     }
1356 
1357     /* Else place in bin */
1358 
1359     frontlink(victim, victim_size, remainder_index, bck, fwd);
1360   }
1361 
1362   /*
1363      If there are any possibly nonempty big-enough blocks,
1364      search for best fitting chunk by scanning bins in blockwidth units.
1365   */
1366 
1367   if ( (block = idx2binblock(idx)) <= binblocks_r)
1368   {
1369 
1370     /* Get to the first marked block */
1371 
1372     if ( (block & binblocks_r) == 0)
1373     {
1374       /* force to an even block boundary */
1375       idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
1376       block <<= 1;
1377       while ((block & binblocks_r) == 0)
1378       {
1379 	idx += BINBLOCKWIDTH;
1380 	block <<= 1;
1381       }
1382     }
1383 
1384     /* For each possibly nonempty block ... */
1385     for (;;)
1386     {
1387       startidx = idx;          /* (track incomplete blocks) */
1388       q = bin = bin_at(idx);
1389 
1390       /* For each bin in this block ... */
1391       do
1392       {
1393 	/* Find and use first big enough chunk ... */
1394 
1395 	for (victim = last(bin); victim != bin; victim = victim->bk)
1396 	{
1397 	  victim_size = chunksize(victim);
1398 	  remainder_size = victim_size - nb;
1399 
1400 	  if (remainder_size >= (long)MINSIZE) /* split */
1401 	  {
1402 	    remainder = chunk_at_offset(victim, nb);
1403 	    set_head(victim, nb | PREV_INUSE);
1404 	    unlink(victim, bck, fwd);
1405 	    link_last_remainder(remainder);
1406 	    set_head(remainder, remainder_size | PREV_INUSE);
1407 	    set_foot(remainder, remainder_size);
1408 	    check_malloced_chunk(victim, nb);
1409 	    return chunk2mem(victim);
1410 	  }
1411 
1412 	  else if (remainder_size >= 0)  /* take */
1413 	  {
1414 	    set_inuse_bit_at_offset(victim, victim_size);
1415 	    unlink(victim, bck, fwd);
1416 	    check_malloced_chunk(victim, nb);
1417 	    return chunk2mem(victim);
1418 	  }
1419 
1420 	}
1421 
1422        bin = next_bin(bin);
1423 
1424       } while ((++idx & (BINBLOCKWIDTH - 1)) != 0);
1425 
1426       /* Clear out the block bit. */
1427 
1428       do   /* Possibly backtrack to try to clear a partial block */
1429       {
1430 	if ((startidx & (BINBLOCKWIDTH - 1)) == 0)
1431 	{
1432 	  av_[1] = (mbinptr)(binblocks_r & ~block);
1433 	  break;
1434 	}
1435 	--startidx;
1436        q = prev_bin(q);
1437       } while (first(q) == q);
1438 
1439       /* Get to the next possibly nonempty block */
1440 
1441       if ( (block <<= 1) <= binblocks_r && (block != 0) )
1442       {
1443 	while ((block & binblocks_r) == 0)
1444 	{
1445 	  idx += BINBLOCKWIDTH;
1446 	  block <<= 1;
1447 	}
1448       }
1449       else
1450 	break;
1451     }
1452   }
1453 
1454 
1455   /* Try to use top chunk */
1456 
1457   /* Require that there be a remainder, ensuring top always exists  */
1458   if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
1459   {
1460 
1461 #if HAVE_MMAP
1462     /* If big and would otherwise need to extend, try to use mmap instead */
1463     if ((unsigned long)nb >= (unsigned long)mmap_threshold &&
1464 	(victim = mmap_chunk(nb)) != 0)
1465       return chunk2mem(victim);
1466 #endif
1467 
1468     /* Try to extend */
1469     malloc_extend_top(nb);
1470     if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
1471       return NULL; /* propagate failure */
1472   }
1473 
1474   victim = top;
1475   set_head(victim, nb | PREV_INUSE);
1476   top = chunk_at_offset(victim, nb);
1477   set_head(top, remainder_size | PREV_INUSE);
1478   check_malloced_chunk(victim, nb);
1479   return chunk2mem(victim);
1480 
1481 }
1482 
1483 
1484 
1485 
1486 /*
1487 
1488   free() algorithm :
1489 
1490     cases:
1491 
1492        1. free(0) has no effect.
1493 
1494        2. If the chunk was allocated via mmap, it is release via munmap().
1495 
1496        3. If a returned chunk borders the current high end of memory,
1497 	  it is consolidated into the top, and if the total unused
1498 	  topmost memory exceeds the trim threshold, malloc_trim is
1499 	  called.
1500 
1501        4. Other chunks are consolidated as they arrive, and
1502 	  placed in corresponding bins. (This includes the case of
1503 	  consolidating with the current `last_remainder').
1504 
1505 */
1506 
1507 
1508 #if __STD_C
1509 void fREe(Void_t* mem)
1510 #else
1511 void fREe(mem) Void_t* mem;
1512 #endif
1513 {
1514   mchunkptr p;         /* chunk corresponding to mem */
1515   INTERNAL_SIZE_T hd;  /* its head field */
1516   INTERNAL_SIZE_T sz;  /* its size */
1517   int       idx;       /* its bin index */
1518   mchunkptr next;      /* next contiguous chunk */
1519   INTERNAL_SIZE_T nextsz; /* its size */
1520   INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */
1521   mchunkptr bck;       /* misc temp for linking */
1522   mchunkptr fwd;       /* misc temp for linking */
1523   int       islr;      /* track whether merging with last_remainder */
1524 
1525 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1526 	/* free() is a no-op - all the memory will be freed on relocation */
1527 	if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT))
1528 		return;
1529 #endif
1530 
1531   if (mem == NULL)                              /* free(0) has no effect */
1532     return;
1533 
1534   p = mem2chunk(mem);
1535   hd = p->size;
1536 
1537 #if HAVE_MMAP
1538   if (hd & IS_MMAPPED)                       /* release mmapped memory. */
1539   {
1540     munmap_chunk(p);
1541     return;
1542   }
1543 #endif
1544 
1545   check_inuse_chunk(p);
1546 
1547   sz = hd & ~PREV_INUSE;
1548   next = chunk_at_offset(p, sz);
1549   nextsz = chunksize(next);
1550 
1551   if (next == top)                            /* merge with top */
1552   {
1553     sz += nextsz;
1554 
1555     if (!(hd & PREV_INUSE))                    /* consolidate backward */
1556     {
1557       prevsz = p->prev_size;
1558       p = chunk_at_offset(p, -((long) prevsz));
1559       sz += prevsz;
1560       unlink(p, bck, fwd);
1561     }
1562 
1563     set_head(p, sz | PREV_INUSE);
1564     top = p;
1565     if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
1566       malloc_trim(top_pad);
1567     return;
1568   }
1569 
1570   set_head(next, nextsz);                    /* clear inuse bit */
1571 
1572   islr = 0;
1573 
1574   if (!(hd & PREV_INUSE))                    /* consolidate backward */
1575   {
1576     prevsz = p->prev_size;
1577     p = chunk_at_offset(p, -((long) prevsz));
1578     sz += prevsz;
1579 
1580     if (p->fd == last_remainder)             /* keep as last_remainder */
1581       islr = 1;
1582     else
1583       unlink(p, bck, fwd);
1584   }
1585 
1586   if (!(inuse_bit_at_offset(next, nextsz)))   /* consolidate forward */
1587   {
1588     sz += nextsz;
1589 
1590     if (!islr && next->fd == last_remainder)  /* re-insert last_remainder */
1591     {
1592       islr = 1;
1593       link_last_remainder(p);
1594     }
1595     else
1596       unlink(next, bck, fwd);
1597   }
1598 
1599 
1600   set_head(p, sz | PREV_INUSE);
1601   set_foot(p, sz);
1602   if (!islr)
1603     frontlink(p, sz, idx, bck, fwd);
1604 }
1605 
1606 
1607 
1608 
1609 
1610 /*
1611 
1612   Realloc algorithm:
1613 
1614     Chunks that were obtained via mmap cannot be extended or shrunk
1615     unless HAVE_MREMAP is defined, in which case mremap is used.
1616     Otherwise, if their reallocation is for additional space, they are
1617     copied.  If for less, they are just left alone.
1618 
1619     Otherwise, if the reallocation is for additional space, and the
1620     chunk can be extended, it is, else a malloc-copy-free sequence is
1621     taken.  There are several different ways that a chunk could be
1622     extended. All are tried:
1623 
1624        * Extending forward into following adjacent free chunk.
1625        * Shifting backwards, joining preceding adjacent space
1626        * Both shifting backwards and extending forward.
1627        * Extending into newly sbrked space
1628 
1629     Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
1630     size argument of zero (re)allocates a minimum-sized chunk.
1631 
1632     If the reallocation is for less space, and the new request is for
1633     a `small' (<512 bytes) size, then the newly unused space is lopped
1634     off and freed.
1635 
1636     The old unix realloc convention of allowing the last-free'd chunk
1637     to be used as an argument to realloc is no longer supported.
1638     I don't know of any programs still relying on this feature,
1639     and allowing it would also allow too many other incorrect
1640     usages of realloc to be sensible.
1641 
1642 
1643 */
1644 
1645 
1646 #if __STD_C
1647 Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
1648 #else
1649 Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
1650 #endif
1651 {
1652   INTERNAL_SIZE_T    nb;      /* padded request size */
1653 
1654   mchunkptr oldp;             /* chunk corresponding to oldmem */
1655   INTERNAL_SIZE_T    oldsize; /* its size */
1656 
1657   mchunkptr newp;             /* chunk to return */
1658   INTERNAL_SIZE_T    newsize; /* its size */
1659   Void_t*   newmem;           /* corresponding user mem */
1660 
1661   mchunkptr next;             /* next contiguous chunk after oldp */
1662   INTERNAL_SIZE_T  nextsize;  /* its size */
1663 
1664   mchunkptr prev;             /* previous contiguous chunk before oldp */
1665   INTERNAL_SIZE_T  prevsize;  /* its size */
1666 
1667   mchunkptr remainder;        /* holds split off extra space from newp */
1668   INTERNAL_SIZE_T  remainder_size;   /* its size */
1669 
1670   mchunkptr bck;              /* misc temp for linking */
1671   mchunkptr fwd;              /* misc temp for linking */
1672 
1673 #ifdef REALLOC_ZERO_BYTES_FREES
1674   if (bytes == 0) { fREe(oldmem); return 0; }
1675 #endif
1676 
1677   if ((long)bytes < 0) return NULL;
1678 
1679   /* realloc of null is supposed to be same as malloc */
1680   if (oldmem == NULL) return mALLOc(bytes);
1681 
1682 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
1683 	if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT)) {
1684 		/* This is harder to support and should not be needed */
1685 		panic("pre-reloc realloc() is not supported");
1686 	}
1687 #endif
1688 
1689   newp    = oldp    = mem2chunk(oldmem);
1690   newsize = oldsize = chunksize(oldp);
1691 
1692 
1693   nb = request2size(bytes);
1694 
1695 #if HAVE_MMAP
1696   if (chunk_is_mmapped(oldp))
1697   {
1698 #if HAVE_MREMAP
1699     newp = mremap_chunk(oldp, nb);
1700     if(newp) return chunk2mem(newp);
1701 #endif
1702     /* Note the extra SIZE_SZ overhead. */
1703     if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
1704     /* Must alloc, copy, free. */
1705     newmem = mALLOc(bytes);
1706     if (newmem == 0) return 0; /* propagate failure */
1707     MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
1708     munmap_chunk(oldp);
1709     return newmem;
1710   }
1711 #endif
1712 
1713   check_inuse_chunk(oldp);
1714 
1715   if ((long)(oldsize) < (long)(nb))
1716   {
1717 
1718     /* Try expanding forward */
1719 
1720     next = chunk_at_offset(oldp, oldsize);
1721     if (next == top || !inuse(next))
1722     {
1723       nextsize = chunksize(next);
1724 
1725       /* Forward into top only if a remainder */
1726       if (next == top)
1727       {
1728 	if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE))
1729 	{
1730 	  newsize += nextsize;
1731 	  top = chunk_at_offset(oldp, nb);
1732 	  set_head(top, (newsize - nb) | PREV_INUSE);
1733 	  set_head_size(oldp, nb);
1734 	  return chunk2mem(oldp);
1735 	}
1736       }
1737 
1738       /* Forward into next chunk */
1739       else if (((long)(nextsize + newsize) >= (long)(nb)))
1740       {
1741 	unlink(next, bck, fwd);
1742 	newsize  += nextsize;
1743 	goto split;
1744       }
1745     }
1746     else
1747     {
1748       next = NULL;
1749       nextsize = 0;
1750     }
1751 
1752     /* Try shifting backwards. */
1753 
1754     if (!prev_inuse(oldp))
1755     {
1756       prev = prev_chunk(oldp);
1757       prevsize = chunksize(prev);
1758 
1759       /* try forward + backward first to save a later consolidation */
1760 
1761       if (next != NULL)
1762       {
1763 	/* into top */
1764 	if (next == top)
1765 	{
1766 	  if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE))
1767 	  {
1768 	    unlink(prev, bck, fwd);
1769 	    newp = prev;
1770 	    newsize += prevsize + nextsize;
1771 	    newmem = chunk2mem(newp);
1772 	    MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1773 	    top = chunk_at_offset(newp, nb);
1774 	    set_head(top, (newsize - nb) | PREV_INUSE);
1775 	    set_head_size(newp, nb);
1776 	    return newmem;
1777 	  }
1778 	}
1779 
1780 	/* into next chunk */
1781 	else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
1782 	{
1783 	  unlink(next, bck, fwd);
1784 	  unlink(prev, bck, fwd);
1785 	  newp = prev;
1786 	  newsize += nextsize + prevsize;
1787 	  newmem = chunk2mem(newp);
1788 	  MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1789 	  goto split;
1790 	}
1791       }
1792 
1793       /* backward only */
1794       if (prev != NULL && (long)(prevsize + newsize) >= (long)nb)
1795       {
1796 	unlink(prev, bck, fwd);
1797 	newp = prev;
1798 	newsize += prevsize;
1799 	newmem = chunk2mem(newp);
1800 	MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1801 	goto split;
1802       }
1803     }
1804 
1805     /* Must allocate */
1806 
1807     newmem = mALLOc (bytes);
1808 
1809     if (newmem == NULL)  /* propagate failure */
1810       return NULL;
1811 
1812     /* Avoid copy if newp is next chunk after oldp. */
1813     /* (This can only happen when new chunk is sbrk'ed.) */
1814 
1815     if ( (newp = mem2chunk(newmem)) == next_chunk(oldp))
1816     {
1817       newsize += chunksize(newp);
1818       newp = oldp;
1819       goto split;
1820     }
1821 
1822     /* Otherwise copy, free, and exit */
1823     MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
1824     fREe(oldmem);
1825     return newmem;
1826   }
1827 
1828 
1829  split:  /* split off extra room in old or expanded chunk */
1830 
1831   if (newsize - nb >= MINSIZE) /* split off remainder */
1832   {
1833     remainder = chunk_at_offset(newp, nb);
1834     remainder_size = newsize - nb;
1835     set_head_size(newp, nb);
1836     set_head(remainder, remainder_size | PREV_INUSE);
1837     set_inuse_bit_at_offset(remainder, remainder_size);
1838     fREe(chunk2mem(remainder)); /* let free() deal with it */
1839   }
1840   else
1841   {
1842     set_head_size(newp, newsize);
1843     set_inuse_bit_at_offset(newp, newsize);
1844   }
1845 
1846   check_inuse_chunk(newp);
1847   return chunk2mem(newp);
1848 }
1849 
1850 
1851 
1852 
1853 /*
1854 
1855   memalign algorithm:
1856 
1857     memalign requests more than enough space from malloc, finds a spot
1858     within that chunk that meets the alignment request, and then
1859     possibly frees the leading and trailing space.
1860 
1861     The alignment argument must be a power of two. This property is not
1862     checked by memalign, so misuse may result in random runtime errors.
1863 
1864     8-byte alignment is guaranteed by normal malloc calls, so don't
1865     bother calling memalign with an argument of 8 or less.
1866 
1867     Overreliance on memalign is a sure way to fragment space.
1868 
1869 */
1870 
1871 
1872 #if __STD_C
1873 Void_t* mEMALIGn(size_t alignment, size_t bytes)
1874 #else
1875 Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
1876 #endif
1877 {
1878   INTERNAL_SIZE_T    nb;      /* padded  request size */
1879   char*     m;                /* memory returned by malloc call */
1880   mchunkptr p;                /* corresponding chunk */
1881   char*     brk;              /* alignment point within p */
1882   mchunkptr newp;             /* chunk to return */
1883   INTERNAL_SIZE_T  newsize;   /* its size */
1884   INTERNAL_SIZE_T  leadsize;  /* leading space befor alignment point */
1885   mchunkptr remainder;        /* spare room at end to split off */
1886   long      remainder_size;   /* its size */
1887 
1888   if ((long)bytes < 0) return NULL;
1889 
1890   /* If need less alignment than we give anyway, just relay to malloc */
1891 
1892   if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);
1893 
1894   /* Otherwise, ensure that it is at least a minimum chunk size */
1895 
1896   if (alignment <  MINSIZE) alignment = MINSIZE;
1897 
1898   /* Call malloc with worst case padding to hit alignment. */
1899 
1900   nb = request2size(bytes);
1901   m  = (char*)(mALLOc(nb + alignment + MINSIZE));
1902 
1903   /*
1904   * The attempt to over-allocate (with a size large enough to guarantee the
1905   * ability to find an aligned region within allocated memory) failed.
1906   *
1907   * Try again, this time only allocating exactly the size the user wants. If
1908   * the allocation now succeeds and just happens to be aligned, we can still
1909   * fulfill the user's request.
1910   */
1911   if (m == NULL) {
1912     size_t extra, extra2;
1913     /*
1914      * Use bytes not nb, since mALLOc internally calls request2size too, and
1915      * each call increases the size to allocate, to account for the header.
1916      */
1917     m  = (char*)(mALLOc(bytes));
1918     /* Aligned -> return it */
1919     if ((((unsigned long)(m)) % alignment) == 0)
1920       return m;
1921     /*
1922      * Otherwise, try again, requesting enough extra space to be able to
1923      * acquire alignment.
1924      */
1925     fREe(m);
1926     /* Add in extra bytes to match misalignment of unexpanded allocation */
1927     extra = alignment - (((unsigned long)(m)) % alignment);
1928     m  = (char*)(mALLOc(bytes + extra));
1929     /*
1930      * m might not be the same as before. Validate that the previous value of
1931      * extra still works for the current value of m.
1932      * If (!m), extra2=alignment so
1933      */
1934     if (m) {
1935       extra2 = alignment - (((unsigned long)(m)) % alignment);
1936       if (extra2 > extra) {
1937         fREe(m);
1938         m = NULL;
1939       }
1940     }
1941     /* Fall through to original NULL check and chunk splitting logic */
1942   }
1943 
1944   if (m == NULL) return NULL; /* propagate failure */
1945 
1946   p = mem2chunk(m);
1947 
1948   if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
1949   {
1950 #if HAVE_MMAP
1951     if(chunk_is_mmapped(p))
1952       return chunk2mem(p); /* nothing more to do */
1953 #endif
1954   }
1955   else /* misaligned */
1956   {
1957     /*
1958       Find an aligned spot inside chunk.
1959       Since we need to give back leading space in a chunk of at
1960       least MINSIZE, if the first calculation places us at
1961       a spot with less than MINSIZE leader, we can move to the
1962       next aligned spot -- we've allocated enough total room so that
1963       this is always possible.
1964     */
1965 
1966     brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment));
1967     if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment;
1968 
1969     newp = (mchunkptr)brk;
1970     leadsize = brk - (char*)(p);
1971     newsize = chunksize(p) - leadsize;
1972 
1973 #if HAVE_MMAP
1974     if(chunk_is_mmapped(p))
1975     {
1976       newp->prev_size = p->prev_size + leadsize;
1977       set_head(newp, newsize|IS_MMAPPED);
1978       return chunk2mem(newp);
1979     }
1980 #endif
1981 
1982     /* give back leader, use the rest */
1983 
1984     set_head(newp, newsize | PREV_INUSE);
1985     set_inuse_bit_at_offset(newp, newsize);
1986     set_head_size(p, leadsize);
1987     fREe(chunk2mem(p));
1988     p = newp;
1989 
1990     assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0);
1991   }
1992 
1993   /* Also give back spare room at the end */
1994 
1995   remainder_size = chunksize(p) - nb;
1996 
1997   if (remainder_size >= (long)MINSIZE)
1998   {
1999     remainder = chunk_at_offset(p, nb);
2000     set_head(remainder, remainder_size | PREV_INUSE);
2001     set_head_size(p, nb);
2002     fREe(chunk2mem(remainder));
2003   }
2004 
2005   check_inuse_chunk(p);
2006   return chunk2mem(p);
2007 
2008 }
2009 
2010 
2011 
2012 
2013 /*
2014     valloc just invokes memalign with alignment argument equal
2015     to the page size of the system (or as near to this as can
2016     be figured out from all the includes/defines above.)
2017 */
2018 
2019 #if __STD_C
2020 Void_t* vALLOc(size_t bytes)
2021 #else
2022 Void_t* vALLOc(bytes) size_t bytes;
2023 #endif
2024 {
2025   return mEMALIGn (malloc_getpagesize, bytes);
2026 }
2027 
2028 /*
2029   pvalloc just invokes valloc for the nearest pagesize
2030   that will accommodate request
2031 */
2032 
2033 
2034 #if __STD_C
2035 Void_t* pvALLOc(size_t bytes)
2036 #else
2037 Void_t* pvALLOc(bytes) size_t bytes;
2038 #endif
2039 {
2040   size_t pagesize = malloc_getpagesize;
2041   return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
2042 }
2043 
2044 /*
2045 
2046   calloc calls malloc, then zeroes out the allocated chunk.
2047 
2048 */
2049 
2050 #if __STD_C
2051 Void_t* cALLOc(size_t n, size_t elem_size)
2052 #else
2053 Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
2054 #endif
2055 {
2056   mchunkptr p;
2057   INTERNAL_SIZE_T csz;
2058 
2059   INTERNAL_SIZE_T sz = n * elem_size;
2060 
2061 
2062   /* check if expand_top called, in which case don't need to clear */
2063 #ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
2064 #if MORECORE_CLEARS
2065   mchunkptr oldtop = top;
2066   INTERNAL_SIZE_T oldtopsize = chunksize(top);
2067 #endif
2068 #endif
2069   Void_t* mem = mALLOc (sz);
2070 
2071   if ((long)n < 0) return NULL;
2072 
2073   if (mem == NULL)
2074     return NULL;
2075   else
2076   {
2077 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
2078 	if (!(gd->flags & GD_FLG_FULL_MALLOC_INIT)) {
2079 		MALLOC_ZERO(mem, sz);
2080 		return mem;
2081 	}
2082 #endif
2083     p = mem2chunk(mem);
2084 
2085     /* Two optional cases in which clearing not necessary */
2086 
2087 
2088 #if HAVE_MMAP
2089     if (chunk_is_mmapped(p)) return mem;
2090 #endif
2091 
2092     csz = chunksize(p);
2093 
2094 #ifdef CONFIG_SYS_MALLOC_CLEAR_ON_INIT
2095 #if MORECORE_CLEARS
2096     if (p == oldtop && csz > oldtopsize)
2097     {
2098       /* clear only the bytes from non-freshly-sbrked memory */
2099       csz = oldtopsize;
2100     }
2101 #endif
2102 #endif
2103 
2104     MALLOC_ZERO(mem, csz - SIZE_SZ);
2105     return mem;
2106   }
2107 }
2108 
2109 /*
2110 
2111   cfree just calls free. It is needed/defined on some systems
2112   that pair it with calloc, presumably for odd historical reasons.
2113 
2114 */
2115 
2116 #if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__)
2117 #if __STD_C
2118 void cfree(Void_t *mem)
2119 #else
2120 void cfree(mem) Void_t *mem;
2121 #endif
2122 {
2123   fREe(mem);
2124 }
2125 #endif
2126 
2127 
2128 
2129 /*
2130 
2131     Malloc_trim gives memory back to the system (via negative
2132     arguments to sbrk) if there is unused memory at the `high' end of
2133     the malloc pool. You can call this after freeing large blocks of
2134     memory to potentially reduce the system-level memory requirements
2135     of a program. However, it cannot guarantee to reduce memory. Under
2136     some allocation patterns, some large free blocks of memory will be
2137     locked between two used chunks, so they cannot be given back to
2138     the system.
2139 
2140     The `pad' argument to malloc_trim represents the amount of free
2141     trailing space to leave untrimmed. If this argument is zero,
2142     only the minimum amount of memory to maintain internal data
2143     structures will be left (one page or less). Non-zero arguments
2144     can be supplied to maintain enough trailing space to service
2145     future expected allocations without having to re-obtain memory
2146     from the system.
2147 
2148     Malloc_trim returns 1 if it actually released any memory, else 0.
2149 
2150 */
2151 
2152 #if __STD_C
2153 int malloc_trim(size_t pad)
2154 #else
2155 int malloc_trim(pad) size_t pad;
2156 #endif
2157 {
2158   long  top_size;        /* Amount of top-most memory */
2159   long  extra;           /* Amount to release */
2160   char* current_brk;     /* address returned by pre-check sbrk call */
2161   char* new_brk;         /* address returned by negative sbrk call */
2162 
2163   unsigned long pagesz = malloc_getpagesize;
2164 
2165   top_size = chunksize(top);
2166   extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
2167 
2168   if (extra < (long)pagesz)  /* Not enough memory to release */
2169     return 0;
2170 
2171   else
2172   {
2173     /* Test to make sure no one else called sbrk */
2174     current_brk = (char*)(MORECORE (0));
2175     if (current_brk != (char*)(top) + top_size)
2176       return 0;     /* Apparently we don't own memory; must fail */
2177 
2178     else
2179     {
2180       new_brk = (char*)(MORECORE (-extra));
2181 
2182       if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */
2183       {
2184 	/* Try to figure out what we have */
2185 	current_brk = (char*)(MORECORE (0));
2186 	top_size = current_brk - (char*)top;
2187 	if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
2188 	{
2189 	  sbrked_mem = current_brk - sbrk_base;
2190 	  set_head(top, top_size | PREV_INUSE);
2191 	}
2192 	check_chunk(top);
2193 	return 0;
2194       }
2195 
2196       else
2197       {
2198 	/* Success. Adjust top accordingly. */
2199 	set_head(top, (top_size - extra) | PREV_INUSE);
2200 	sbrked_mem -= extra;
2201 	check_chunk(top);
2202 	return 1;
2203       }
2204     }
2205   }
2206 }
2207 
2208 
2209 
2210 /*
2211   malloc_usable_size:
2212 
2213     This routine tells you how many bytes you can actually use in an
2214     allocated chunk, which may be more than you requested (although
2215     often not). You can use this many bytes without worrying about
2216     overwriting other allocated objects. Not a particularly great
2217     programming practice, but still sometimes useful.
2218 
2219 */
2220 
2221 #if __STD_C
2222 size_t malloc_usable_size(Void_t* mem)
2223 #else
2224 size_t malloc_usable_size(mem) Void_t* mem;
2225 #endif
2226 {
2227   mchunkptr p;
2228   if (mem == NULL)
2229     return 0;
2230   else
2231   {
2232     p = mem2chunk(mem);
2233     if(!chunk_is_mmapped(p))
2234     {
2235       if (!inuse(p)) return 0;
2236       check_inuse_chunk(p);
2237       return chunksize(p) - SIZE_SZ;
2238     }
2239     return chunksize(p) - 2*SIZE_SZ;
2240   }
2241 }
2242 
2243 
2244 
2245 
2246 /* Utility to update current_mallinfo for malloc_stats and mallinfo() */
2247 
2248 #ifdef DEBUG
2249 static void malloc_update_mallinfo()
2250 {
2251   int i;
2252   mbinptr b;
2253   mchunkptr p;
2254 #ifdef DEBUG
2255   mchunkptr q;
2256 #endif
2257 
2258   INTERNAL_SIZE_T avail = chunksize(top);
2259   int   navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;
2260 
2261   for (i = 1; i < NAV; ++i)
2262   {
2263     b = bin_at(i);
2264     for (p = last(b); p != b; p = p->bk)
2265     {
2266 #ifdef DEBUG
2267       check_free_chunk(p);
2268       for (q = next_chunk(p);
2269 	   q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
2270 	   q = next_chunk(q))
2271 	check_inuse_chunk(q);
2272 #endif
2273       avail += chunksize(p);
2274       navail++;
2275     }
2276   }
2277 
2278   current_mallinfo.ordblks = navail;
2279   current_mallinfo.uordblks = sbrked_mem - avail;
2280   current_mallinfo.fordblks = avail;
2281   current_mallinfo.hblks = n_mmaps;
2282   current_mallinfo.hblkhd = mmapped_mem;
2283   current_mallinfo.keepcost = chunksize(top);
2284 
2285 }
2286 #endif	/* DEBUG */
2287 
2288 
2289 
2290 /*
2291 
2292   malloc_stats:
2293 
2294     Prints on the amount of space obtain from the system (both
2295     via sbrk and mmap), the maximum amount (which may be more than
2296     current if malloc_trim and/or munmap got called), the maximum
2297     number of simultaneous mmap regions used, and the current number
2298     of bytes allocated via malloc (or realloc, etc) but not yet
2299     freed. (Note that this is the number of bytes allocated, not the
2300     number requested. It will be larger than the number requested
2301     because of alignment and bookkeeping overhead.)
2302 
2303 */
2304 
2305 #ifdef DEBUG
2306 void malloc_stats()
2307 {
2308   malloc_update_mallinfo();
2309   printf("max system bytes = %10u\n",
2310 	  (unsigned int)(max_total_mem));
2311   printf("system bytes     = %10u\n",
2312 	  (unsigned int)(sbrked_mem + mmapped_mem));
2313   printf("in use bytes     = %10u\n",
2314 	  (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
2315 #if HAVE_MMAP
2316   printf("max mmap regions = %10u\n",
2317 	  (unsigned int)max_n_mmaps);
2318 #endif
2319 }
2320 #endif	/* DEBUG */
2321 
2322 /*
2323   mallinfo returns a copy of updated current mallinfo.
2324 */
2325 
2326 #ifdef DEBUG
2327 struct mallinfo mALLINFo()
2328 {
2329   malloc_update_mallinfo();
2330   return current_mallinfo;
2331 }
2332 #endif	/* DEBUG */
2333 
2334 
2335 
2336 
2337 /*
2338   mallopt:
2339 
2340     mallopt is the general SVID/XPG interface to tunable parameters.
2341     The format is to provide a (parameter-number, parameter-value) pair.
2342     mallopt then sets the corresponding parameter to the argument
2343     value if it can (i.e., so long as the value is meaningful),
2344     and returns 1 if successful else 0.
2345 
2346     See descriptions of tunable parameters above.
2347 
2348 */
2349 
2350 #if __STD_C
2351 int mALLOPt(int param_number, int value)
2352 #else
2353 int mALLOPt(param_number, value) int param_number; int value;
2354 #endif
2355 {
2356   switch(param_number)
2357   {
2358     case M_TRIM_THRESHOLD:
2359       trim_threshold = value; return 1;
2360     case M_TOP_PAD:
2361       top_pad = value; return 1;
2362     case M_MMAP_THRESHOLD:
2363       mmap_threshold = value; return 1;
2364     case M_MMAP_MAX:
2365 #if HAVE_MMAP
2366       n_mmaps_max = value; return 1;
2367 #else
2368       if (value != 0) return 0; else  n_mmaps_max = value; return 1;
2369 #endif
2370 
2371     default:
2372       return 0;
2373   }
2374 }
2375 
2376 int initf_malloc(void)
2377 {
2378 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
2379 	assert(gd->malloc_base);	/* Set up by crt0.S */
2380 	gd->malloc_limit = CONFIG_VAL(SYS_MALLOC_F_LEN);
2381 	gd->malloc_ptr = 0;
2382 #endif
2383 
2384 	return 0;
2385 }
2386 
2387 /*
2388 
2389 History:
2390 
2391     V2.6.6 Sun Dec  5 07:42:19 1999  Doug Lea  (dl at gee)
2392       * return null for negative arguments
2393       * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com>
2394 	 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
2395 	  (e.g. WIN32 platforms)
2396 	 * Cleanup up header file inclusion for WIN32 platforms
2397 	 * Cleanup code to avoid Microsoft Visual C++ compiler complaints
2398 	 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
2399 	   memory allocation routines
2400 	 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
2401 	 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
2402 	   usage of 'assert' in non-WIN32 code
2403 	 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
2404 	   avoid infinite loop
2405       * Always call 'fREe()' rather than 'free()'
2406 
2407     V2.6.5 Wed Jun 17 15:57:31 1998  Doug Lea  (dl at gee)
2408       * Fixed ordering problem with boundary-stamping
2409 
2410     V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
2411       * Added pvalloc, as recommended by H.J. Liu
2412       * Added 64bit pointer support mainly from Wolfram Gloger
2413       * Added anonymously donated WIN32 sbrk emulation
2414       * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
2415       * malloc_extend_top: fix mask error that caused wastage after
2416 	foreign sbrks
2417       * Add linux mremap support code from HJ Liu
2418 
2419     V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
2420       * Integrated most documentation with the code.
2421       * Add support for mmap, with help from
2422 	Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
2423       * Use last_remainder in more cases.
2424       * Pack bins using idea from  colin@nyx10.cs.du.edu
2425       * Use ordered bins instead of best-fit threshhold
2426       * Eliminate block-local decls to simplify tracing and debugging.
2427       * Support another case of realloc via move into top
2428       * Fix error occuring when initial sbrk_base not word-aligned.
2429       * Rely on page size for units instead of SBRK_UNIT to
2430 	avoid surprises about sbrk alignment conventions.
2431       * Add mallinfo, mallopt. Thanks to Raymond Nijssen
2432 	(raymond@es.ele.tue.nl) for the suggestion.
2433       * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
2434       * More precautions for cases where other routines call sbrk,
2435 	courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
2436       * Added macros etc., allowing use in linux libc from
2437 	H.J. Lu (hjl@gnu.ai.mit.edu)
2438       * Inverted this history list
2439 
2440     V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
2441       * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
2442       * Removed all preallocation code since under current scheme
2443 	the work required to undo bad preallocations exceeds
2444 	the work saved in good cases for most test programs.
2445       * No longer use return list or unconsolidated bins since
2446 	no scheme using them consistently outperforms those that don't
2447 	given above changes.
2448       * Use best fit for very large chunks to prevent some worst-cases.
2449       * Added some support for debugging
2450 
2451     V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
2452       * Removed footers when chunks are in use. Thanks to
2453 	Paul Wilson (wilson@cs.texas.edu) for the suggestion.
2454 
2455     V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
2456       * Added malloc_trim, with help from Wolfram Gloger
2457 	(wmglo@Dent.MED.Uni-Muenchen.DE).
2458 
2459     V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)
2460 
2461     V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
2462       * realloc: try to expand in both directions
2463       * malloc: swap order of clean-bin strategy;
2464       * realloc: only conditionally expand backwards
2465       * Try not to scavenge used bins
2466       * Use bin counts as a guide to preallocation
2467       * Occasionally bin return list chunks in first scan
2468       * Add a few optimizations from colin@nyx10.cs.du.edu
2469 
2470     V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
2471       * faster bin computation & slightly different binning
2472       * merged all consolidations to one part of malloc proper
2473 	 (eliminating old malloc_find_space & malloc_clean_bin)
2474       * Scan 2 returns chunks (not just 1)
2475       * Propagate failure in realloc if malloc returns 0
2476       * Add stuff to allow compilation on non-ANSI compilers
2477 	  from kpv@research.att.com
2478 
2479     V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
2480       * removed potential for odd address access in prev_chunk
2481       * removed dependency on getpagesize.h
2482       * misc cosmetics and a bit more internal documentation
2483       * anticosmetics: mangled names in macros to evade debugger strangeness
2484       * tested on sparc, hp-700, dec-mips, rs6000
2485 	  with gcc & native cc (hp, dec only) allowing
2486 	  Detlefs & Zorn comparison study (in SIGPLAN Notices.)
2487 
2488     Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
2489       * Based loosely on libg++-1.2X malloc. (It retains some of the overall
2490 	 structure of old version,  but most details differ.)
2491 
2492 */
2493