Outline ![]()
Files ![]()
loading...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
/*
* SPDX-FileCopyrightText: 2006-2016 Matthew Conte
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <string.h>
#include <limits.h>
#include <stdio.h>
#include "tlsf.h"
#include "tlsf_block_functions.h"
#include "tlsf_control_functions.h"
/*
** Static assertion mechanism.
*/
#define _tlsf_glue2(x, y) x ## y
#define _tlsf_glue(x, y) _tlsf_glue2(x, y)
#define tlsf_static_assert(exp) \
typedef char _tlsf_glue(static_assert, __LINE__) [(exp) ? 1 : -1]
/* This code has been tested on 32- and 64-bit (LP/LLP) architectures. */
tlsf_static_assert(sizeof(int) * CHAR_BIT == 32);
tlsf_static_assert(sizeof(size_t) * CHAR_BIT >= 32);
tlsf_static_assert(sizeof(size_t) * CHAR_BIT <= 64);
/* Clear structure and point all empty lists at the null block. */
static control_t* control_construct(control_t* control, size_t bytes)
{
// check that the requested size can at least hold the control_t. This will allow us
// to fill in the field of control_t necessary to determine the final size of
// the metadata overhead and check that the requested size can hold
// this data and at least a block of minimum size
if (bytes < sizeof(control_t))
{
return NULL;
}
/* Find the closest power of two for first layer */
control->fl_index_max = 32 - __builtin_clz(bytes);
/* Adapt second layer to the pool */
if (bytes <= 16 * 1024) control->sl_index_count_log2 = 3;
else if (bytes <= 256 * 1024) control->sl_index_count_log2 = 4;
else control->sl_index_count_log2 = 5;
control->fl_index_shift = (control->sl_index_count_log2 + ALIGN_SIZE_LOG2);
control->sl_index_count = 1 << control->sl_index_count_log2;
control->fl_index_count = control->fl_index_max - control->fl_index_shift + 1;
control->small_block_size = 1 << control->fl_index_shift;
// the total size fo the metadata overhead is the size of the control_t
// added to the size of the sl_bitmaps and the size of blocks
control->size = sizeof(control_t) + (sizeof(*control->sl_bitmap) * control->fl_index_count) +
(sizeof(*control->blocks) * (control->fl_index_count * control->sl_index_count));
// check that the requested size can hold the whole control structure and
// a small block at least
if (bytes < control->size + block_size_min)
{
return NULL;
}
control->block_null.next_free = &control->block_null;
control->block_null.prev_free = &control->block_null;
control->fl_bitmap = 0;
control->sl_bitmap = align_ptr(control + 1, sizeof(*control->sl_bitmap));
control->blocks = align_ptr(control->sl_bitmap + control->fl_index_count, sizeof(*control->blocks));
/* SL_INDEX_COUNT must be <= number of bits in sl_bitmap's storage type. */
tlsf_assert(sizeof(unsigned int) * CHAR_BIT >= control->sl_index_count
&& "CHAR_BIT less than sl_index_count");
/* Ensure we've properly tuned our sizes. */
tlsf_assert(ALIGN_SIZE == control->small_block_size / control->sl_index_count); //ALIGN_SIZE does not match");
for (int i = 0; i < control->fl_index_count; ++i)
{
control->sl_bitmap[i] = 0;
for (int j = 0; j < control->sl_index_count; ++j)
{
control->blocks[i * control->sl_index_count + j] = &control->block_null;
}
}
return control;
}
/*
** Debugging utilities.
*/
typedef struct integrity_t
{
int prev_status;
int status;
} integrity_t;
#define tlsf_insist(x) { if (!(x)) { status--; } }
static bool integrity_walker(void* ptr, size_t size, int used, void* user)
{
block_header_t* block = block_from_ptr(ptr);
integrity_t* integ = tlsf_cast(integrity_t*, user);
const int this_prev_status = block_is_prev_free(block) ? 1 : 0;
const int this_status = block_is_free(block) ? 1 : 0;
const size_t this_block_size = block_size(block);
int status = 0;
tlsf_insist(integ->prev_status == this_prev_status && "prev status incorrect");
tlsf_insist(size == this_block_size && "block size incorrect");
if (tlsf_check_hook != NULL)
{
/* block_size(block) returns the size of the usable memory when the block is allocated.
* As the block under test is free, we need to subtract to the block size the next_free
* and prev_free fields of the block header as they are not a part of the usable memory
* when the block is free. In addition, we also need to subtract the size of prev_phys_block
* as this field is in fact part of the current free block and not part of the next (allocated)
* block. Check the comments in block_split function for more details.
*/
const size_t actual_free_block_size = used ? this_block_size :
this_block_size - offsetof(block_header_t, next_free)- block_header_overhead;
void* ptr_block = used ? (void*)block + block_start_offset :
(void*)block + sizeof(block_header_t);
tlsf_insist(tlsf_check_hook(ptr_block, actual_free_block_size, !used));
}
integ->prev_status = this_status;
integ->status += status;
return true;
}
int tlsf_check(tlsf_t tlsf)
{
int i, j;
control_t* control = tlsf_cast(control_t*, tlsf);
int status = 0;
/* Check that the free lists and bitmaps are accurate. */
for (i = 0; i < control->fl_index_count; ++i)
{
for (j = 0; j < control->sl_index_count; ++j)
{
const int fl_map = control->fl_bitmap & (1U << i);
const int sl_list = control->sl_bitmap[i];
const int sl_map = sl_list & (1U << j);
const block_header_t* block = control->blocks[i * control->sl_index_count + j];
/* Check that first- and second-level lists agree. */
if (!fl_map)
{
tlsf_insist(!sl_map && "second-level map must be null");
}
if (!sl_map)
{
tlsf_insist(block == &control->block_null && "block list must be null");
continue;
}
/* Check that there is at least one free block. */
tlsf_insist(sl_list && "no free blocks in second-level map");
tlsf_insist(block != &control->block_null && "block should not be null");
while (block != &control->block_null)
{
int fli, sli;
const bool is_block_free = block_is_free(block);
tlsf_insist(is_block_free && "block should be free");
tlsf_insist(!block_is_prev_free(block) && "blocks should have coalesced");
tlsf_insist(!block_is_free(block_next(block)) && "blocks should have coalesced");
tlsf_insist(block_is_prev_free(block_next(block)) && "block should be free");
tlsf_insist(block_size(block) >= block_size_min && "block not minimum size");
mapping_insert(control, block_size(block), &fli, &sli);
tlsf_insist(fli == i && sli == j && "block size indexed in wrong list");
block = block->next_free;
}
}
}
return status;
}
#undef tlsf_insist
static bool default_walker(void* ptr, size_t size, int used, void* user)
{
(void)user;
printf("\t%p %s size: %x (%p)\n", ptr, used ? "used" : "free", (unsigned int)size, block_from_ptr(ptr));
return true;
}
void tlsf_walk_pool(pool_t pool, tlsf_walker walker, void* user)
{
tlsf_walker pool_walker = walker ? walker : default_walker;
block_header_t* block =
offset_to_block(pool, -(int)block_header_overhead);
bool ret_val = true;
while (block && !block_is_last(block) && ret_val == true)
{
ret_val = pool_walker(
block_to_ptr(block),
block_size(block),
!block_is_free(block),
user);
if (ret_val == true) {
block = block_next(block);
}
}
}
size_t tlsf_block_size(void* ptr)
{
size_t size = 0;
if (ptr)
{
const block_header_t* block = block_from_ptr(ptr);
size = block_size(block);
}
return size;
}
int tlsf_check_pool(pool_t pool)
{
/* Check that the blocks are physically correct. */
integrity_t integ = { 0, 0 };
tlsf_walk_pool(pool, integrity_walker, &integ);
return integ.status;
}
size_t tlsf_fit_size(tlsf_t tlsf, size_t size)
{
if (size == 0 || tlsf == NULL) {
return 0;
}
control_t* control = tlsf_cast(control_t*, tlsf);
if (size < control->small_block_size) {
return adjust_request_size(tlsf, size, ALIGN_SIZE);
}
/* because it's GoodFit, allocable size is one range lower */
size_t sl_interval;
sl_interval = (1 << (32 - __builtin_clz(size) - 1)) / control->sl_index_count;
return size & ~(sl_interval - 1);
}
/*
** Size of the TLSF structures in a given memory block passed to
** tlsf_create, equal to the size of a control_t
*/
size_t tlsf_size(tlsf_t tlsf)
{
if (tlsf == NULL)
{
return 0;
}
control_t* control = tlsf_cast(control_t*, tlsf);
return control->size;
}
/*
** Overhead of the TLSF structures in a given memory block passed to
** tlsf_add_pool, equal to the overhead of a free block and the
** sentinel block.
*/
size_t tlsf_pool_overhead(void)
{
return 2 * block_header_overhead;
}
size_t tlsf_alloc_overhead(void)
{
return block_header_overhead;
}
pool_t tlsf_add_pool(tlsf_t tlsf, void* mem, size_t bytes)
{
block_header_t* block;
block_header_t* next;
const size_t pool_overhead = tlsf_pool_overhead();
const size_t pool_bytes = align_down(bytes - pool_overhead, ALIGN_SIZE);
if (((ptrdiff_t)mem % ALIGN_SIZE) != 0)
{
printf("tlsf_add_pool: Memory must be aligned by %u bytes.\n",
(unsigned int)ALIGN_SIZE);
return 0;
}
if (pool_bytes < block_size_min || pool_bytes > tlsf_block_size_max(tlsf))
{
#if defined (TLSF_64BIT)
printf("tlsf_add_pool: Memory size must be between 0x%x and 0x%x00 bytes.\n",
(unsigned int)(pool_overhead + block_size_min),
(unsigned int)((pool_overhead + tlsf_block_size_max(tlsf)) / 256));
#else
printf("tlsf_add_pool: Memory size must be between %u and %u bytes.\n",
(unsigned int)(pool_overhead + block_size_min),
(unsigned int)(pool_overhead + tlsf_block_size_max(tlsf)));
#endif
return 0;
}
/*
** Create the main free block. Offset the start of the block slightly
** so that the prev_phys_block field falls outside of the pool -
** it will never be used.
*/
block = offset_to_block(mem, -(tlsfptr_t)block_header_overhead);
block_set_size(block, pool_bytes);
block_set_free(block);
block_set_prev_used(block);
block_insert(tlsf_cast(control_t*, tlsf), block);
/* Split the block to create a zero-size sentinel block. */
next = block_link_next(block);
block_set_size(next, 0);
block_set_used(next);
block_set_prev_free(next);
return mem;
}
void tlsf_remove_pool(tlsf_t tlsf, pool_t pool)
{
control_t* control = tlsf_cast(control_t*, tlsf);
block_header_t* block = offset_to_block(pool, -(int)block_header_overhead);
int fl = 0, sl = 0;
tlsf_assert(block_is_free(block) && "block should be free");
tlsf_assert(!block_is_free(block_next(block)) && "next block should not be free");
tlsf_assert(block_size(block_next(block)) == 0 && "next block size should be zero");
mapping_insert(control, block_size(block), &fl, &sl);
remove_free_block(control, block, fl, sl);
}
/*
** TLSF main interface.
*/
#if _DEBUG
int test_ffs_fls()
{
/* Verify ffs/fls work properly. */
int rv = 0;
rv += (tlsf_ffs(0) == -1) ? 0 : 0x1;
rv += (tlsf_fls(0) == -1) ? 0 : 0x2;
rv += (tlsf_ffs(1) == 0) ? 0 : 0x4;
rv += (tlsf_fls(1) == 0) ? 0 : 0x8;
rv += (tlsf_ffs(0x80000000) == 31) ? 0 : 0x10;
rv += (tlsf_ffs(0x80008000) == 15) ? 0 : 0x20;
rv += (tlsf_fls(0x80000008) == 31) ? 0 : 0x40;
rv += (tlsf_fls(0x7FFFFFFF) == 30) ? 0 : 0x80;
#if defined (TLSF_64BIT)
rv += (tlsf_fls_sizet(0x80000000) == 31) ? 0 : 0x100;
rv += (tlsf_fls_sizet(0x100000000) == 32) ? 0 : 0x200;
rv += (tlsf_fls_sizet(0xffffffffffffffff) == 63) ? 0 : 0x400;
#endif
if (rv)
{
printf("test_ffs_fls: %x ffs/fls tests failed.\n", rv);
}
return rv;
}
#endif
tlsf_t tlsf_create(void* mem, size_t max_bytes)
{
#if _DEBUG
if (test_ffs_fls())
{
return NULL;
}
#endif
if (mem == NULL)
{
return NULL;
}
if (((tlsfptr_t)mem % ALIGN_SIZE) != 0)
{
printf("tlsf_create: Memory must be aligned to %u bytes.\n",
(unsigned int)ALIGN_SIZE);
return NULL;
}
control_t* control_ptr = control_construct(tlsf_cast(control_t*, mem), max_bytes);
return tlsf_cast(tlsf_t, control_ptr);
}
tlsf_t tlsf_create_with_pool(void* mem, size_t pool_bytes, size_t max_bytes)
{
tlsf_t tlsf = tlsf_create(mem, max_bytes ? max_bytes : pool_bytes);
if (tlsf != NULL)
{
tlsf_add_pool(tlsf, (char*)mem + tlsf_size(tlsf), pool_bytes - tlsf_size(tlsf));
}
return tlsf;
}
void tlsf_destroy(tlsf_t tlsf)
{
/* Nothing to do. */
(void)tlsf;
}
pool_t tlsf_get_pool(tlsf_t tlsf)
{
return tlsf_cast(pool_t, (char*)tlsf + tlsf_size(tlsf));
}
void* tlsf_malloc(tlsf_t tlsf, size_t size)
{
control_t* control = tlsf_cast(control_t*, tlsf);
size_t adjust = adjust_request_size(tlsf, size, ALIGN_SIZE);
// Returned size is 0 when the requested size is larger than the max block
// size.
if (adjust == 0) {
return NULL;
}
// block_locate_free() may adjust our allocated size further.
block_header_t* block = block_locate_free(control, &adjust);
return block_prepare_used(control, block, adjust);
}
/**
* @brief Allocate memory of at least `size` bytes at a given address in the pool.
*
* @param tlsf TLSF structure to allocate memory from.
* @param size Minimum size, in bytes, of the memory to allocate
* @param address address at which the allocation must be done
*
* @return pointer to free memory or NULL in case of incapacity to perform the malloc
*/
void* tlsf_malloc_addr(tlsf_t tlsf, size_t size, void *address)
{
control_t* control = tlsf_cast(control_t*, tlsf);
/* adjust the address to be ALIGN_SIZE bytes aligned. */
const unsigned int addr_adjusted = align_down(tlsf_cast(unsigned int, address), ALIGN_SIZE);
/* adjust the size to be ALIGN_SIZE bytes aligned. Add to the size the difference
* between the requested address and the address_adjusted. */
size_t size_adjusted = align_up(size + (tlsf_cast(unsigned int, address) - addr_adjusted), ALIGN_SIZE);
/* find the free block that starts before the address in the pool and is big enough
* to support the size of allocation at the given address */
block_header_t* block = offset_to_block(tlsf_get_pool(tlsf), -(int)block_header_overhead);
const char *alloc_start = tlsf_cast(char*, addr_adjusted);
const char *alloc_end = alloc_start + size_adjusted;
bool block_found = false;
do {
const char *block_start = tlsf_cast(char*, block_to_ptr(block));
const char *block_end = tlsf_cast(char*, block_to_ptr(block)) + block_size(block);
if (block_start <= alloc_start && block_end > alloc_start) {
/* A: block_end >= alloc_end. B: block is free */
if (block_end < alloc_end || !block_is_free(block)) {
/* not(A) || not(B)
* We won't find another suitable block from this point on
* so we can break and return NULL */
break;
}
/* A && B
* The block can fit the alloc and is located at a position allowing for the alloc
* to be placed at the given address. We can return from the while */
block_found = true;
} else if (!block_is_last(block)) {
/* the block doesn't match the expected criteria, continue with the next block */
block = block_next(block);
}
} while (!block_is_last(block) && block_found == false);
if (!block_found) {
return NULL;
}
/* remove block from the free list since a part of it will be used */
block_remove(control, block);
/* trim any leading space or add the leading space to the overall requested size
* if the leading space is not big enough to store a block of minimum size */
const size_t space_before_addr_adjusted = addr_adjusted - tlsf_cast(unsigned int, block_to_ptr(block));
block_header_t *return_block = block;
if (space_before_addr_adjusted >= block_size_min) {
return_block = block_trim_free_leading(control, block, space_before_addr_adjusted);
}
else {
size_adjusted += space_before_addr_adjusted;
}
/* trim trailing space if any and return a pointer to the first usable byte allocated */
return block_prepare_used(control, return_block, size_adjusted);
}
/**
* @brief Allocate memory of at least `size` bytes where byte at `data_offset` will be aligned to `alignment`.
*
* This function will allocate memory pointed by `ptr`. However, the byte at `data_offset` of
* this piece of memory (i.e., byte at `ptr` + `data_offset`) will be aligned to `alignment`.
* This function is useful for allocating memory that will internally have a header, and the
* usable memory following the header (i.e. `ptr` + `data_offset`) must be aligned.
*
* For example, a call to `multi_heap_aligned_alloc_impl_offs(heap, 64, 256, 20)` will return a
* pointer `ptr` to free memory of minimum 64 bytes, where `ptr + 20` is aligned on `256`.
* So `(ptr + 20) % 256` equals 0.
*
* @param tlsf TLSF structure to allocate memory from.
* @param align Alignment for the returned pointer's offset.
* @param size Minimum size, in bytes, of the memory to allocate INCLUDING
* `data_offset` bytes.
* @param data_offset Offset to be aligned on `alignment`. This can be 0, in
* this case, the returned pointer will be aligned on
* `alignment`. If it is not a multiple of CPU word size,
* it will be aligned up to the closest multiple of it.
*
* @return pointer to free memory.
*/
void* tlsf_memalign_offs(tlsf_t tlsf, size_t align, size_t size, size_t data_offset)
{
control_t* control = tlsf_cast(control_t*, tlsf);
const size_t adjust = adjust_request_size(tlsf, size, ALIGN_SIZE);
const size_t off_adjust = align_up(data_offset, ALIGN_SIZE);
/*
** We must allocate an additional minimum block size bytes so that if
** our free block will leave an alignment gap which is smaller, we can
** trim a leading free block and release it back to the pool. We must
** do this because the previous physical block is in use, therefore
** the prev_phys_block field is not valid, and we can't simply adjust
** the size of that block.
*/
const size_t gap_minimum = sizeof(block_header_t) + off_adjust;
/* The offset is included in both `adjust` and `gap_minimum`, so we
** need to subtract it once.
*/
const size_t size_with_gap = adjust_request_size(tlsf, adjust + align + gap_minimum - off_adjust, align);
/*
** If alignment is less than or equal to base alignment, we're done, because
** we are guaranteed that the size is at least sizeof(block_header_t), enough
** to store next blocks' metadata. Plus, all pointers allocated will all be
** aligned on a 4-byte bound, so ptr + data_offset will also have this
** alignment constraint. Thus, the gap is not required.
** If we requested 0 bytes, return null, as tlsf_malloc(0) does.
*/
size_t aligned_size = (adjust && align > ALIGN_SIZE) ? size_with_gap : adjust;
block_header_t* block = block_locate_free(control, &aligned_size);
/* This can't be a static assert. */
tlsf_assert(sizeof(block_header_t) == block_size_min + block_header_overhead);
if (block)
{
void* ptr = block_to_ptr(block);
void* aligned = align_ptr(ptr, align);
size_t gap = tlsf_cast(size_t,
tlsf_cast(tlsfptr_t, aligned) - tlsf_cast(tlsfptr_t, ptr));
/*
** If gap size is too small or if there is no gap but we need one,
** offset to next aligned boundary.
** NOTE: No need for a gap if the alignment required is less than or is
** equal to ALIGN_SIZE.
*/
if ((gap && gap < gap_minimum) || (!gap && off_adjust && align > ALIGN_SIZE))
{
const size_t gap_remain = gap_minimum - gap;
const size_t offset = tlsf_max(gap_remain, align);
const void* next_aligned = tlsf_cast(void*,
tlsf_cast(tlsfptr_t, aligned) + offset);
aligned = align_ptr(next_aligned, align);
gap = tlsf_cast(size_t,
tlsf_cast(tlsfptr_t, aligned) - tlsf_cast(tlsfptr_t, ptr));
}
if (gap)
{
tlsf_assert(gap >= gap_minimum && "gap size too small");
block = block_trim_free_leading(control, block, gap - off_adjust);
}
}
/* Preparing the block will also the trailing free memory. */
return block_prepare_used(control, block, adjust);
}
/**
* @brief Same as `tlsf_memalign_offs` function but with a 0 offset.
* The pointer returned is aligned on `align`.
*/
void* tlsf_memalign(tlsf_t tlsf, size_t align, size_t size)
{
return tlsf_memalign_offs(tlsf, align, size, 0);
}
void tlsf_free(tlsf_t tlsf, void* ptr)
{
/* Don't attempt to free a NULL pointer. */
if (ptr)
{
control_t* control = tlsf_cast(control_t*, tlsf);
block_header_t* block = block_from_ptr(ptr);
tlsf_assert(!block_is_free(block) && "block already marked as free");
block_mark_as_free(block);
block = block_merge_prev(control, block);
block = block_merge_next(control, block);
block_insert(control, block);
}
}
/*
** The TLSF block information provides us with enough information to
** provide a reasonably intelligent implementation of realloc, growing or
** shrinking the currently allocated block as required.
**
** This routine handles the somewhat esoteric edge cases of realloc:
** - a non-zero size with a null pointer will behave like malloc
** - a zero size with a non-null pointer will behave like free
** - a request that cannot be satisfied will leave the original buffer
** untouched
** - an extended buffer size will leave the newly-allocated area with
** contents undefined
*/
void* tlsf_realloc(tlsf_t tlsf, void* ptr, size_t size)
{
control_t* control = tlsf_cast(control_t*, tlsf);
void* p = 0;
/* Zero-size requests are treated as free. */
if (ptr && size == 0)
{
tlsf_free(tlsf, ptr);
}
/* Requests with NULL pointers are treated as malloc. */
else if (!ptr)
{
p = tlsf_malloc(tlsf, size);
}
else
{
block_header_t* block = block_from_ptr(ptr);
block_header_t* next = block_next(block);
const size_t cursize = block_size(block);
const size_t combined = cursize + block_size(next) + block_header_overhead;
const size_t adjust = adjust_request_size(tlsf, size, ALIGN_SIZE);
// if adjust if equal to 0, the size is too big
if (adjust == 0)
{
return p;
}
tlsf_assert(!block_is_free(block) && "block already marked as free");
/*
** If the next block is used, or when combined with the current
** block, does not offer enough space, we must reallocate and copy.
*/
if (adjust > cursize && (!block_is_free(next) || adjust > combined))
{
p = tlsf_malloc(tlsf, size);
if (p)
{
const size_t minsize = tlsf_min(cursize, size);
memcpy(p, ptr, minsize);
tlsf_free(tlsf, ptr);
}
}
else
{
/* Do we need to expand to the next block? */
if (adjust > cursize)
{
block_merge_next(control, block);
block_mark_as_used(block);
}
/* Trim the resulting block and return the original pointer. */
block_trim_used(control, block, adjust);
p = ptr;
}
}
return p;
}
Details ![]()
Show: from Types: Columns: ![]( "Show Project Names")
![]( "Show Locations")
![]( "Show Referring Symbols")
![]( "Show Scope")
This file uses the notable symbols shown below. Click anywhere in the file to view more details.