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1 1254 phoenix
/* ---------- To make a malloc.h, start cutting here ------------ */
2
 
3
/*
4
  A version of malloc/free/realloc written by Doug Lea and released to the
5
  public domain.  Send questions/comments/complaints/performance data
6
  to dl@cs.oswego.edu
7
 
8
* VERSION 2.6.4  Thu Nov 28 07:54:55 1996  Doug Lea  (dl at gee)
9
 
10
   Note: There may be an updated version of this malloc obtainable at
11
           ftp://g.oswego.edu/pub/misc/malloc.c
12
         Check before installing!
13
 
14
* Why use this malloc?
15
 
16
  This is not the fastest, most space-conserving, most portable, or
17
  most tunable malloc ever written. However it is among the fastest
18
  while also being among the most space-conserving, portable and tunable.
19
  Consistent balance across these factors results in a good general-purpose
20
  allocator. For a high-level description, see
21
     http://g.oswego.edu/dl/html/malloc.html
22
 
23
* Synopsis of public routines
24
 
25
  (Much fuller descriptions are contained in the program documentation below.)
26
 
27
  malloc(size_t n);
28
     Return a pointer to a newly allocated chunk of at least n bytes, or null
29
     if no space is available.
30
  free(Void_t* p);
31
     Release the chunk of memory pointed to by p, or no effect if p is null.
32
  realloc(Void_t* p, size_t n);
33
     Return a pointer to a chunk of size n that contains the same data
34
     as does chunk p up to the minimum of (n, p's size) bytes, or null
35
     if no space is available. The returned pointer may or may not be
36
     the same as p. If p is null, equivalent to malloc.  Unless the
37
     #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
38
     size argument of zero (re)allocates a minimum-sized chunk.
39
  memalign(size_t alignment, size_t n);
40
     Return a pointer to a newly allocated chunk of n bytes, aligned
41
     in accord with the alignment argument, which must be a power of
42
     two.
43
  valloc(size_t n);
44
     Equivalent to memalign(pagesize, n), where pagesize is the page
45
     size of the system (or as near to this as can be figured out from
46
     all the includes/defines below.)
47
  pvalloc(size_t n);
48
     Equivalent to valloc(minimum-page-that-holds(n)), that is,
49
     round up n to nearest pagesize.
50
  calloc(size_t unit, size_t quantity);
51
     Returns a pointer to quantity * unit bytes, with all locations
52
     set to zero.
53
  cfree(Void_t* p);
54
     Equivalent to free(p).
55
  malloc_trim(size_t pad);
56
     Release all but pad bytes of freed top-most memory back
57
     to the system. Return 1 if successful, else 0.
58
  malloc_usable_size(Void_t* p);
59
     Report the number usable allocated bytes associated with allocated
60
     chunk p. This may or may not report more bytes than were requested,
61
     due to alignment and minimum size constraints.
62
  malloc_stats();
63
     Prints brief summary statistics on stderr.
64
  mallinfo()
65
     Returns (by copy) a struct containing various summary statistics.
66
  mallopt(int parameter_number, int parameter_value)
67
     Changes one of the tunable parameters described below. Returns
68
     1 if successful in changing the parameter, else 0.
69
 
70
* Vital statistics:
71
 
72
  Alignment:                            8-byte
73
       8 byte alignment is currently hardwired into the design.  This
74
       seems to suffice for all current machines and C compilers.
75
 
76
  Assumed pointer representation:       4 or 8 bytes
77
       Code for 8-byte pointers is untested by me but has worked
78
       reliably by Wolfram Gloger, who contributed most of the
79
       changes supporting this.
80
 
81
  Assumed size_t  representation:       4 or 8 bytes
82
       Note that size_t is allowed to be 4 bytes even if pointers are 8.
83
 
84
  Minimum overhead per allocated chunk: 4 or 8 bytes
85
       Each malloced chunk has a hidden overhead of 4 bytes holding size
86
       and status information.
87
 
88
  Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
89
                          8-byte ptrs:  24/32 bytes (including, 4/8 overhead)
90
 
91
       When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
92
       ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
93
       needed; 4 (8) for a trailing size field
94
       and 8 (16) bytes for free list pointers. Thus, the minimum
95
       allocatable size is 16/24/32 bytes.
96
 
97
       Even a request for zero bytes (i.e., malloc(0)) returns a
98
       pointer to something of the minimum allocatable size.
99
 
100
  Maximum allocated size: 4-byte size_t: 2^31 -  8 bytes
101
                          8-byte size_t: 2^63 - 16 bytes
102
 
103
       It is assumed that (possibly signed) size_t bit values suffice to
104
       represent chunk sizes. `Possibly signed' is due to the fact
105
       that `size_t' may be defined on a system as either a signed or
106
       an unsigned type. To be conservative, values that would appear
107
       as negative numbers are avoided.
108
       Requests for sizes with a negative sign bit will return a
109
       minimum-sized chunk.
110
 
111
  Maximum overhead wastage per allocated chunk: normally 15 bytes
112
 
113
       Alignnment demands, plus the minimum allocatable size restriction
114
       make the normal worst-case wastage 15 bytes (i.e., up to 15
115
       more bytes will be allocated than were requested in malloc), with
116
       two exceptions:
117
         1. Because requests for zero bytes allocate non-zero space,
118
            the worst case wastage for a request of zero bytes is 24 bytes.
119
         2. For requests >= mmap_threshold that are serviced via
120
            mmap(), the worst case wastage is 8 bytes plus the remainder
121
            from a system page (the minimal mmap unit); typically 4096 bytes.
122
 
123
* Limitations
124
 
125
    Here are some features that are NOT currently supported
126
 
127
    * No user-definable hooks for callbacks and the like.
128
    * No automated mechanism for fully checking that all accesses
129
      to malloced memory stay within their bounds.
130
    * No support for compaction.
131
 
132
* Synopsis of compile-time options:
133
 
134
    People have reported using previous versions of this malloc on all
135
    versions of Unix, sometimes by tweaking some of the defines
136
    below. It has been tested most extensively on Solaris and
137
    Linux. It is also reported to work on WIN32 platforms.
138
    People have also reported adapting this malloc for use in
139
    stand-alone embedded systems.
140
 
141
    The implementation is in straight, hand-tuned ANSI C.  Among other
142
    consequences, it uses a lot of macros.  Because of this, to be at
143
    all usable, this code should be compiled using an optimizing compiler
144
    (for example gcc -O2) that can simplify expressions and control
145
    paths.
146
 
147
  __STD_C                  (default: derived from C compiler defines)
148
     Nonzero if using ANSI-standard C compiler, a C++ compiler, or
149
     a C compiler sufficiently close to ANSI to get away with it.
150
  DEBUG                    (default: NOT defined)
151
     Define to enable debugging. Adds fairly extensive assertion-based
152
     checking to help track down memory errors, but noticeably slows down
153
     execution.
154
  REALLOC_ZERO_BYTES_FREES (default: NOT defined)
155
     Define this if you think that realloc(p, 0) should be equivalent
156
     to free(p). Otherwise, since malloc returns a unique pointer for
157
     malloc(0), so does realloc(p, 0).
158
  HAVE_MEMCPY               (default: defined)
159
     Define if you are not otherwise using ANSI STD C, but still
160
     have memcpy and memset in your C library and want to use them.
161
     Otherwise, simple internal versions are supplied.
162
  USE_MEMCPY               (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
163
     Define as 1 if you want the C library versions of memset and
164
     memcpy called in realloc and calloc (otherwise macro versions are used).
165
     At least on some platforms, the simple macro versions usually
166
     outperform libc versions.
167
  HAVE_MMAP                 (default: defined as 1)
168
     Define to non-zero to optionally make malloc() use mmap() to
169
     allocate very large blocks.
170
  HAVE_MREMAP                 (default: defined as 0 unless Linux libc set)
171
     Define to non-zero to optionally make realloc() use mremap() to
172
     reallocate very large blocks.
173
  malloc_getpagesize        (default: derived from system #includes)
174
     Either a constant or routine call returning the system page size.
175
  HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
176
     Optionally define if you are on a system with a /usr/include/malloc.h
177
     that declares struct mallinfo. It is not at all necessary to
178
     define this even if you do, but will ensure consistency.
179
  INTERNAL_SIZE_T           (default: size_t)
180
     Define to a 32-bit type (probably `unsigned int') if you are on a
181
     64-bit machine, yet do not want or need to allow malloc requests of
182
     greater than 2^31 to be handled. This saves space, especially for
183
     very small chunks.
184
  INTERNAL_LINUX_C_LIB      (default: NOT defined)
185
     Defined only when compiled as part of Linux libc.
186
     Also note that there is some odd internal name-mangling via defines
187
     (for example, internally, `malloc' is named `mALLOc') needed
188
     when compiling in this case. These look funny but don't otherwise
189
     affect anything.
190
  WIN32                     (default: undefined)
191
     Define this on MS win (95, nt) platforms to compile in sbrk emulation.
192
  LACKS_UNISTD_H            (default: undefined)
193
     Define this if your system does not have a <unistd.h>.
194
  MORECORE                  (default: sbrk)
195
     The name of the routine to call to obtain more memory from the system.
196
  MORECORE_FAILURE          (default: -1)
197
     The value returned upon failure of MORECORE.
198
  MORECORE_CLEARS           (default 1)
199
     True (1) if the routine mapped to MORECORE zeroes out memory (which
200
     holds for sbrk).
201
  DEFAULT_TRIM_THRESHOLD
202
  DEFAULT_TOP_PAD
203
  DEFAULT_MMAP_THRESHOLD
204
  DEFAULT_MMAP_MAX
205
     Default values of tunable parameters (described in detail below)
206
     controlling interaction with host system routines (sbrk, mmap, etc).
207
     These values may also be changed dynamically via mallopt(). The
208
     preset defaults are those that give best performance for typical
209
     programs/systems.
210
 
211
 
212
*/
213
 
214
 
215
 
216
 
217
/* Preliminaries */
218
 
219
#ifndef __STD_C
220
#ifdef __STDC__
221
#define __STD_C     1
222
#else
223
#if __cplusplus
224
#define __STD_C     1
225
#else
226
#define __STD_C     0
227
#endif /*__cplusplus*/
228
#endif /*__STDC__*/
229
#endif /*__STD_C*/
230
 
231
#ifndef Void_t
232
#if __STD_C
233
#define Void_t      void
234
#else
235
#define Void_t      char
236
#endif
237
#endif /*Void_t*/
238
 
239
#if __STD_C
240
#include <stddef.h>   /* for size_t */
241
#else
242
#include <sys/types.h>
243
#endif
244
 
245
#ifdef __cplusplus
246
extern "C" {
247
#endif
248
 
249
#include <stdio.h>    /* needed for malloc_stats */
250
 
251
 
252
/*
253
  Compile-time options
254
*/
255
 
256
 
257
/*
258
    Debugging:
259
 
260
    Because freed chunks may be overwritten with link fields, this
261
    malloc will often die when freed memory is overwritten by user
262
    programs.  This can be very effective (albeit in an annoying way)
263
    in helping track down dangling pointers.
264
 
265
    If you compile with -DDEBUG, a number of assertion checks are
266
    enabled that will catch more memory errors. You probably won't be
267
    able to make much sense of the actual assertion errors, but they
268
    should help you locate incorrectly overwritten memory.  The
269
    checking is fairly extensive, and will slow down execution
270
    noticeably. Calling malloc_stats or mallinfo with DEBUG set will
271
    attempt to check every non-mmapped allocated and free chunk in the
272
    course of computing the summmaries. (By nature, mmapped regions
273
    cannot be checked very much automatically.)
274
 
275
    Setting DEBUG may also be helpful if you are trying to modify
276
    this code. The assertions in the check routines spell out in more
277
    detail the assumptions and invariants underlying the algorithms.
278
 
279
*/
280
 
281
#if DEBUG 
282
#include <assert.h>
283
#else
284
#define assert(x) ((void)0)
285
#endif
286
 
287
 
288
/*
289
  INTERNAL_SIZE_T is the word-size used for internal bookkeeping
290
  of chunk sizes. On a 64-bit machine, you can reduce malloc
291
  overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
292
  at the expense of not being able to handle requests greater than
293
  2^31. This limitation is hardly ever a concern; you are encouraged
294
  to set this. However, the default version is the same as size_t.
295
*/
296
 
297
#ifndef INTERNAL_SIZE_T
298
#define INTERNAL_SIZE_T size_t
299
#endif
300
 
301
/*
302
  REALLOC_ZERO_BYTES_FREES should be set if a call to
303
  realloc with zero bytes should be the same as a call to free.
304
  Some people think it should. Otherwise, since this malloc
305
  returns a unique pointer for malloc(0), so does realloc(p, 0).
306
*/
307
 
308
 
309
/*   #define REALLOC_ZERO_BYTES_FREES */
310
 
311
 
312
/*
313
  WIN32 causes an emulation of sbrk to be compiled in
314
  mmap-based options are not currently supported in WIN32.
315
*/
316
 
317
/* #define WIN32 */
318
#ifdef WIN32
319
#define MORECORE wsbrk
320
#define HAVE_MMAP 0
321
#endif
322
 
323
 
324
/*
325
  HAVE_MEMCPY should be defined if you are not otherwise using
326
  ANSI STD C, but still have memcpy and memset in your C library
327
  and want to use them in calloc and realloc. Otherwise simple
328
  macro versions are defined here.
329
 
330
  USE_MEMCPY should be defined as 1 if you actually want to
331
  have memset and memcpy called. People report that the macro
332
  versions are often enough faster than libc versions on many
333
  systems that it is better to use them.
334
 
335
*/
336
 
337
#define HAVE_MEMCPY 
338
 
339
#ifndef USE_MEMCPY
340
#ifdef HAVE_MEMCPY
341
#define USE_MEMCPY 1
342
#else
343
#define USE_MEMCPY 0
344
#endif
345
#endif
346
 
347
#if (__STD_C || defined(HAVE_MEMCPY)) 
348
 
349
#if __STD_C
350
void* memset(void*, int, size_t);
351
void* memcpy(void*, const void*, size_t);
352
#else
353
Void_t* memset();
354
Void_t* memcpy();
355
#endif
356
#endif
357
 
358
#if USE_MEMCPY
359
 
360
/* The following macros are only invoked with (2n+1)-multiples of
361
   INTERNAL_SIZE_T units, with a positive integer n. This is exploited
362
   for fast inline execution when n is small. */
363
 
364
#define MALLOC_ZERO(charp, nbytes)                                            \
365
do {                                                                          \
366
  INTERNAL_SIZE_T mzsz = (nbytes);                                            \
367
  if(mzsz <= 9*sizeof(mzsz)) {                                                \
368
    INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
369
    if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
370
                                     *mz++ = 0;                               \
371
      if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
372
                                     *mz++ = 0;                               \
373
        if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
374
                                     *mz++ = 0; }}}                           \
375
                                     *mz++ = 0;                               \
376
                                     *mz++ = 0;                               \
377
                                     *mz   = 0;                               \
378
  } else memset((charp), 0, mzsz);                                            \
379
} while(0)
380
 
381
#define MALLOC_COPY(dest,src,nbytes)                                          \
382
do {                                                                          \
383
  INTERNAL_SIZE_T mcsz = (nbytes);                                            \
384
  if(mcsz <= 9*sizeof(mcsz)) {                                                \
385
    INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
386
    INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
387
    if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
388
                                     *mcdst++ = *mcsrc++;                     \
389
      if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
390
                                     *mcdst++ = *mcsrc++;                     \
391
        if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
392
                                     *mcdst++ = *mcsrc++; }}}                 \
393
                                     *mcdst++ = *mcsrc++;                     \
394
                                     *mcdst++ = *mcsrc++;                     \
395
                                     *mcdst   = *mcsrc  ;                     \
396
  } else memcpy(dest, src, mcsz);                                             \
397
} while(0)
398
 
399
#else /* !USE_MEMCPY */
400
 
401
/* Use Duff's device for good zeroing/copying performance. */
402
 
403
#define MALLOC_ZERO(charp, nbytes)                                            \
404
do {                                                                          \
405
  INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
406
  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
407
  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
408
  switch (mctmp) {                                                            \
409
    case 0: for(;;) { *mzp++ = 0;                                             \
410
    case 7:           *mzp++ = 0;                                             \
411
    case 6:           *mzp++ = 0;                                             \
412
    case 5:           *mzp++ = 0;                                             \
413
    case 4:           *mzp++ = 0;                                             \
414
    case 3:           *mzp++ = 0;                                             \
415
    case 2:           *mzp++ = 0;                                             \
416
    case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
417
  }                                                                           \
418
} while(0)
419
 
420
#define MALLOC_COPY(dest,src,nbytes)                                          \
421
do {                                                                          \
422
  INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
423
  INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
424
  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
425
  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
426
  switch (mctmp) {                                                            \
427
    case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
428
    case 7:           *mcdst++ = *mcsrc++;                                    \
429
    case 6:           *mcdst++ = *mcsrc++;                                    \
430
    case 5:           *mcdst++ = *mcsrc++;                                    \
431
    case 4:           *mcdst++ = *mcsrc++;                                    \
432
    case 3:           *mcdst++ = *mcsrc++;                                    \
433
    case 2:           *mcdst++ = *mcsrc++;                                    \
434
    case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
435
  }                                                                           \
436
} while(0)
437
 
438
#endif
439
 
440
 
441
/*
442
  Define HAVE_MMAP to optionally make malloc() use mmap() to
443
  allocate very large blocks.  These will be returned to the
444
  operating system immediately after a free().
445
*/
446
 
447
#ifndef HAVE_MMAP
448
#define HAVE_MMAP 1
449
#endif
450
 
451
/*
452
  Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
453
  large blocks.  This is currently only possible on Linux with
454
  kernel versions newer than 1.3.77.
455
*/
456
 
457
#ifndef HAVE_MREMAP
458
#ifdef INTERNAL_LINUX_C_LIB
459
#define HAVE_MREMAP 1
460
#else
461
#define HAVE_MREMAP 0
462
#endif
463
#endif
464
 
465
#if HAVE_MMAP
466
 
467
#include <unistd.h>
468
#include <fcntl.h>
469
#include <sys/mman.h>
470
 
471
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
472
#define MAP_ANONYMOUS MAP_ANON
473
#endif
474
 
475
#endif /* HAVE_MMAP */
476
 
477
/*
478
  Access to system page size. To the extent possible, this malloc
479
  manages memory from the system in page-size units.
480
 
481
  The following mechanics for getpagesize were adapted from
482
  bsd/gnu getpagesize.h
483
*/
484
 
485
#ifndef LACKS_UNISTD_H
486
#  include <unistd.h>
487
#endif
488
 
489
#ifndef malloc_getpagesize
490
#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
491
#    ifndef _SC_PAGE_SIZE
492
#      define _SC_PAGE_SIZE _SC_PAGESIZE
493
#    endif
494
#  endif
495
#  ifdef _SC_PAGE_SIZE
496
#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
497
#  else
498
#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
499
       extern size_t getpagesize();
500
#      define malloc_getpagesize getpagesize()
501
#    else
502
#      include <sys/param.h>
503
#      ifdef EXEC_PAGESIZE
504
#        define malloc_getpagesize EXEC_PAGESIZE
505
#      else
506
#        ifdef NBPG
507
#          ifndef CLSIZE
508
#            define malloc_getpagesize NBPG
509
#          else
510
#            define malloc_getpagesize (NBPG * CLSIZE)
511
#          endif
512
#        else 
513
#          ifdef NBPC
514
#            define malloc_getpagesize NBPC
515
#          else
516
#            ifdef PAGESIZE
517
#              define malloc_getpagesize PAGESIZE
518
#            else
519
#              define malloc_getpagesize (4096) /* just guess */
520
#            endif
521
#          endif
522
#        endif 
523
#      endif
524
#    endif 
525
#  endif
526
#endif
527
 
528
 
529
 
530
/*
531
 
532
  This version of malloc supports the standard SVID/XPG mallinfo
533
  routine that returns a struct containing the same kind of
534
  information you can get from malloc_stats. It should work on
535
  any SVID/XPG compliant system that has a /usr/include/malloc.h
536
  defining struct mallinfo. (If you'd like to install such a thing
537
  yourself, cut out the preliminary declarations as described above
538
  and below and save them in a malloc.h file. But there's no
539
  compelling reason to bother to do this.)
540
 
541
  The main declaration needed is the mallinfo struct that is returned
542
  (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
543
  bunch of fields, most of which are not even meaningful in this
544
  version of malloc. Some of these fields are are instead filled by
545
  mallinfo() with other numbers that might possibly be of interest.
546
 
547
  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
548
  /usr/include/malloc.h file that includes a declaration of struct
549
  mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
550
  version is declared below.  These must be precisely the same for
551
  mallinfo() to work.
552
 
553
*/
554
 
555
/* #define HAVE_USR_INCLUDE_MALLOC_H */
556
 
557
#if HAVE_USR_INCLUDE_MALLOC_H
558
#include "/usr/include/malloc.h"
559
#else
560
 
561
/* SVID2/XPG mallinfo structure */
562
 
563
struct mallinfo {
564
  int arena;    /* total space allocated from system */
565
  int ordblks;  /* number of non-inuse chunks */
566
  int smblks;   /* unused -- always zero */
567
  int hblks;    /* number of mmapped regions */
568
  int hblkhd;   /* total space in mmapped regions */
569
  int usmblks;  /* unused -- always zero */
570
  int fsmblks;  /* unused -- always zero */
571
  int uordblks; /* total allocated space */
572
  int fordblks; /* total non-inuse space */
573
  int keepcost; /* top-most, releasable (via malloc_trim) space */
574
};
575
 
576
/* SVID2/XPG mallopt options */
577
 
578
#define M_MXFAST  1    /* UNUSED in this malloc */
579
#define M_NLBLKS  2    /* UNUSED in this malloc */
580
#define M_GRAIN   3    /* UNUSED in this malloc */
581
#define M_KEEP    4    /* UNUSED in this malloc */
582
 
583
#endif
584
 
585
/* mallopt options that actually do something */
586
 
587
#define M_TRIM_THRESHOLD    -1
588
#define M_TOP_PAD           -2
589
#define M_MMAP_THRESHOLD    -3
590
#define M_MMAP_MAX          -4
591
 
592
 
593
 
594
#ifndef DEFAULT_TRIM_THRESHOLD
595
#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
596
#endif
597
 
598
/*
599
    M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
600
      to keep before releasing via malloc_trim in free().
601
 
602
      Automatic trimming is mainly useful in long-lived programs.
603
      Because trimming via sbrk can be slow on some systems, and can
604
      sometimes be wasteful (in cases where programs immediately
605
      afterward allocate more large chunks) the value should be high
606
      enough so that your overall system performance would improve by
607
      releasing.
608
 
609
      The trim threshold and the mmap control parameters (see below)
610
      can be traded off with one another. Trimming and mmapping are
611
      two different ways of releasing unused memory back to the
612
      system. Between these two, it is often possible to keep
613
      system-level demands of a long-lived program down to a bare
614
      minimum. For example, in one test suite of sessions measuring
615
      the XF86 X server on Linux, using a trim threshold of 128K and a
616
      mmap threshold of 192K led to near-minimal long term resource
617
      consumption.
618
 
619
      If you are using this malloc in a long-lived program, it should
620
      pay to experiment with these values.  As a rough guide, you
621
      might set to a value close to the average size of a process
622
      (program) running on your system.  Releasing this much memory
623
      would allow such a process to run in memory.  Generally, it's
624
      worth it to tune for trimming rather tham memory mapping when a
625
      program undergoes phases where several large chunks are
626
      allocated and released in ways that can reuse each other's
627
      storage, perhaps mixed with phases where there are no such
628
      chunks at all.  And in well-behaved long-lived programs,
629
      controlling release of large blocks via trimming versus mapping
630
      is usually faster.
631
 
632
      However, in most programs, these parameters serve mainly as
633
      protection against the system-level effects of carrying around
634
      massive amounts of unneeded memory. Since frequent calls to
635
      sbrk, mmap, and munmap otherwise degrade performance, the default
636
      parameters are set to relatively high values that serve only as
637
      safeguards.
638
 
639
      The default trim value is high enough to cause trimming only in
640
      fairly extreme (by current memory consumption standards) cases.
641
      It must be greater than page size to have any useful effect.  To
642
      disable trimming completely, you can set to (unsigned long)(-1);
643
 
644
 
645
*/
646
 
647
 
648
#ifndef DEFAULT_TOP_PAD
649
#define DEFAULT_TOP_PAD        (0)
650
#endif
651
 
652
/*
653
    M_TOP_PAD is the amount of extra `padding' space to allocate or
654
      retain whenever sbrk is called. It is used in two ways internally:
655
 
656
      * When sbrk is called to extend the top of the arena to satisfy
657
        a new malloc request, this much padding is added to the sbrk
658
        request.
659
 
660
      * When malloc_trim is called automatically from free(),
661
        it is used as the `pad' argument.
662
 
663
      In both cases, the actual amount of padding is rounded
664
      so that the end of the arena is always a system page boundary.
665
 
666
      The main reason for using padding is to avoid calling sbrk so
667
      often. Having even a small pad greatly reduces the likelihood
668
      that nearly every malloc request during program start-up (or
669
      after trimming) will invoke sbrk, which needlessly wastes
670
      time.
671
 
672
      Automatic rounding-up to page-size units is normally sufficient
673
      to avoid measurable overhead, so the default is 0.  However, in
674
      systems where sbrk is relatively slow, it can pay to increase
675
      this value, at the expense of carrying around more memory than
676
      the program needs.
677
 
678
*/
679
 
680
 
681
#ifndef DEFAULT_MMAP_THRESHOLD
682
#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
683
#endif
684
 
685
/*
686
 
687
    M_MMAP_THRESHOLD is the request size threshold for using mmap()
688
      to service a request. Requests of at least this size that cannot
689
      be allocated using already-existing space will be serviced via mmap.
690
      (If enough normal freed space already exists it is used instead.)
691
 
692
      Using mmap segregates relatively large chunks of memory so that
693
      they can be individually obtained and released from the host
694
      system. A request serviced through mmap is never reused by any
695
      other request (at least not directly; the system may just so
696
      happen to remap successive requests to the same locations).
697
 
698
      Segregating space in this way has the benefit that mmapped space
699
      can ALWAYS be individually released back to the system, which
700
      helps keep the system level memory demands of a long-lived
701
      program low. Mapped memory can never become `locked' between
702
      other chunks, as can happen with normally allocated chunks, which
703
      menas that even trimming via malloc_trim would not release them.
704
 
705
      However, it has the disadvantages that:
706
 
707
         1. The space cannot be reclaimed, consolidated, and then
708
            used to service later requests, as happens with normal chunks.
709
         2. It can lead to more wastage because of mmap page alignment
710
            requirements
711
         3. It causes malloc performance to be more dependent on host
712
            system memory management support routines which may vary in
713
            implementation quality and may impose arbitrary
714
            limitations. Generally, servicing a request via normal
715
            malloc steps is faster than going through a system's mmap.
716
 
717
      All together, these considerations should lead you to use mmap
718
      only for relatively large requests.
719
 
720
 
721
*/
722
 
723
 
724
 
725
#ifndef DEFAULT_MMAP_MAX
726
#if HAVE_MMAP
727
#define DEFAULT_MMAP_MAX       (64)
728
#else
729
#define DEFAULT_MMAP_MAX       (0)
730
#endif
731
#endif
732
 
733
/*
734
    M_MMAP_MAX is the maximum number of requests to simultaneously
735
      service using mmap. This parameter exists because:
736
 
737
         1. Some systems have a limited number of internal tables for
738
            use by mmap.
739
         2. In most systems, overreliance on mmap can degrade overall
740
            performance.
741
         3. If a program allocates many large regions, it is probably
742
            better off using normal sbrk-based allocation routines that
743
            can reclaim and reallocate normal heap memory. Using a
744
            small value allows transition into this mode after the
745
            first few allocations.
746
 
747
      Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
748
      the default value is 0, and attempts to set it to non-zero values
749
      in mallopt will fail.
750
*/
751
 
752
 
753
 
754
 
755
/*
756
 
757
  Special defines for linux libc
758
 
759
  Except when compiled using these special defines for Linux libc
760
  using weak aliases, this malloc is NOT designed to work in
761
  multithreaded applications.  No semaphores or other concurrency
762
  control are provided to ensure that multiple malloc or free calls
763
  don't run at the same time, which could be disasterous. A single
764
  semaphore could be used across malloc, realloc, and free (which is
765
  essentially the effect of the linux weak alias approach). It would
766
  be hard to obtain finer granularity.
767
 
768
*/
769
 
770
 
771
#ifdef INTERNAL_LINUX_C_LIB
772
 
773
#if __STD_C
774
 
775
Void_t * __default_morecore_init (ptrdiff_t);
776
Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
777
 
778
#else
779
 
780
Void_t * __default_morecore_init ();
781
Void_t *(*__morecore)() = __default_morecore_init;
782
 
783
#endif
784
 
785
#define MORECORE (*__morecore)
786
#define MORECORE_FAILURE 0
787
#define MORECORE_CLEARS 1 
788
 
789
#else /* INTERNAL_LINUX_C_LIB */
790
 
791
#if __STD_C
792
extern Void_t*     sbrk(ptrdiff_t);
793
#else
794
extern Void_t*     sbrk();
795
#endif
796
 
797
#ifndef MORECORE
798
#define MORECORE sbrk
799
#endif
800
 
801
#ifndef MORECORE_FAILURE
802
#define MORECORE_FAILURE -1
803
#endif
804
 
805
#ifndef MORECORE_CLEARS
806
#define MORECORE_CLEARS 1
807
#endif
808
 
809
#endif /* INTERNAL_LINUX_C_LIB */
810
 
811
#if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)
812
 
813
#define cALLOc          __libc_calloc
814
#define fREe            __libc_free
815
#define mALLOc          __libc_malloc
816
#define mEMALIGn        __libc_memalign
817
#define rEALLOc         __libc_realloc
818
#define vALLOc          __libc_valloc
819
#define pvALLOc         __libc_pvalloc
820
#define mALLINFo        __libc_mallinfo
821
#define mALLOPt         __libc_mallopt
822
 
823
#pragma weak calloc = __libc_calloc
824
#pragma weak free = __libc_free
825
#pragma weak cfree = __libc_free
826
#pragma weak malloc = __libc_malloc
827
#pragma weak memalign = __libc_memalign
828
#pragma weak realloc = __libc_realloc
829
#pragma weak valloc = __libc_valloc
830
#pragma weak pvalloc = __libc_pvalloc
831
#pragma weak mallinfo = __libc_mallinfo
832
#pragma weak mallopt = __libc_mallopt
833
 
834
#else
835
 
836
 
837
#define cALLOc          calloc
838
#define fREe            free
839
#define mALLOc          malloc
840
#define mEMALIGn        memalign
841
#define rEALLOc         realloc
842
#define vALLOc          valloc
843
#define pvALLOc         pvalloc
844
#define mALLINFo        mallinfo
845
#define mALLOPt         mallopt
846
 
847
#endif
848
 
849
/* Public routines */
850
 
851
#if __STD_C
852
 
853
Void_t* mALLOc(size_t);
854
void    fREe(Void_t*);
855
Void_t* rEALLOc(Void_t*, size_t);
856
Void_t* mEMALIGn(size_t, size_t);
857
Void_t* vALLOc(size_t);
858
Void_t* pvALLOc(size_t);
859
Void_t* cALLOc(size_t, size_t);
860
void    cfree(Void_t*);
861
int     malloc_trim(size_t);
862
size_t  malloc_usable_size(Void_t*);
863
void    malloc_stats();
864
int     mALLOPt(int, int);
865
struct mallinfo mALLINFo(void);
866
#else
867
Void_t* mALLOc();
868
void    fREe();
869
Void_t* rEALLOc();
870
Void_t* mEMALIGn();
871
Void_t* vALLOc();
872
Void_t* pvALLOc();
873
Void_t* cALLOc();
874
void    cfree();
875
int     malloc_trim();
876
size_t  malloc_usable_size();
877
void    malloc_stats();
878
int     mALLOPt();
879
struct mallinfo mALLINFo();
880
#endif
881
 
882
 
883
#ifdef __cplusplus
884
};  /* end of extern "C" */
885
#endif
886
 
887
/* ---------- To make a malloc.h, end cutting here ------------ */
888
 
889
 
890
/*
891
  Emulation of sbrk for WIN32
892
  All code within the ifdef WIN32 is untested by me.
893
*/
894
 
895
 
896
#ifdef WIN32
897
 
898
#define AlignPage(add) (((add) + (malloc_getpagesize-1)) &
899
~(malloc_getpagesize-1))
900
 
901
/* resrve 64MB to insure large contiguous space */
902
#define RESERVED_SIZE (1024*1024*64)
903
#define NEXT_SIZE (2048*1024)
904
#define TOP_MEMORY ((unsigned long)2*1024*1024*1024)
905
 
906
struct GmListElement;
907
typedef struct GmListElement GmListElement;
908
 
909
struct GmListElement
910
{
911
        GmListElement* next;
912
        void* base;
913
};
914
 
915
static GmListElement* head = 0;
916
static unsigned int gNextAddress = 0;
917
static unsigned int gAddressBase = 0;
918
static unsigned int gAllocatedSize = 0;
919
 
920
static
921
GmListElement* makeGmListElement (void* bas)
922
{
923
        GmListElement* this;
924
        this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement));
925
        ASSERT (this);
926
        if (this)
927
        {
928
                this->base = bas;
929
                this->next = head;
930
                head = this;
931
        }
932
        return this;
933
}
934
 
935
void gcleanup ()
936
{
937
        BOOL rval;
938
        ASSERT ( (head == NULL) || (head->base == (void*)gAddressBase));
939
        if (gAddressBase && (gNextAddress - gAddressBase))
940
        {
941
                rval = VirtualFree ((void*)gAddressBase,
942
                                                        gNextAddress - gAddressBase,
943
                                                        MEM_DECOMMIT);
944
        ASSERT (rval);
945
        }
946
        while (head)
947
        {
948
                GmListElement* next = head->next;
949
                rval = VirtualFree (head->base, 0, MEM_RELEASE);
950
                ASSERT (rval);
951
                LocalFree (head);
952
                head = next;
953
        }
954
}
955
 
956
static
957
void* findRegion (void* start_address, unsigned long size)
958
{
959
        MEMORY_BASIC_INFORMATION info;
960
        while ((unsigned long)start_address < TOP_MEMORY)
961
        {
962
                VirtualQuery (start_address, &info, sizeof (info));
963
                if (info.State != MEM_FREE)
964
                        start_address = (char*)info.BaseAddress + info.RegionSize;
965
                else if (info.RegionSize >= size)
966
                        return start_address;
967
                else
968
                        start_address = (char*)info.BaseAddress + info.RegionSize;
969
        }
970
        return NULL;
971
 
972
}
973
 
974
 
975
void* wsbrk (long size)
976
{
977
        void* tmp;
978
        if (size > 0)
979
        {
980
                if (gAddressBase == 0)
981
                {
982
                        gAllocatedSize = max (RESERVED_SIZE, AlignPage (size));
983
                        gNextAddress = gAddressBase =
984
                                (unsigned int)VirtualAlloc (NULL, gAllocatedSize,
985
                                                                                        MEM_RESERVE, PAGE_NOACCESS);
986
                } else if (AlignPage (gNextAddress + size) > (gAddressBase +
987
gAllocatedSize))
988
                {
989
                        long new_size = max (NEXT_SIZE, AlignPage (size));
990
                        void* new_address = (void*)(gAddressBase+gAllocatedSize);
991
                        do
992
                        {
993
                                new_address = findRegion (new_address, new_size);
994
 
995
                                if (new_address == 0)
996
                                        return (void*)-1;
997
 
998
                                gAddressBase = gNextAddress =
999
                                        (unsigned int)VirtualAlloc (new_address, new_size,
1000
                                                                                                MEM_RESERVE, PAGE_NOACCESS);
1001
                                // repeat in case of race condition
1002
                                // The region that we found has been snagged 
1003
                                // by another thread
1004
                        }
1005
                        while (gAddressBase == 0);
1006
 
1007
                        ASSERT (new_address == (void*)gAddressBase);
1008
 
1009
                        gAllocatedSize = new_size;
1010
 
1011
                        if (!makeGmListElement ((void*)gAddressBase))
1012
                                return (void*)-1;
1013
                }
1014
                if ((size + gNextAddress) > AlignPage (gNextAddress))
1015
                {
1016
                        void* res;
1017
                        res = VirtualAlloc ((void*)AlignPage (gNextAddress),
1018
                                                                (size + gNextAddress -
1019
                                                                 AlignPage (gNextAddress)),
1020
                                                                MEM_COMMIT, PAGE_READWRITE);
1021
                        if (res == 0)
1022
                                return (void*)-1;
1023
                }
1024
                tmp = (void*)gNextAddress;
1025
                gNextAddress = (unsigned int)tmp + size;
1026
                return tmp;
1027
        }
1028
        else if (size < 0)
1029
        {
1030
                unsigned int alignedGoal = AlignPage (gNextAddress + size);
1031
                /* Trim by releasing the virtual memory */
1032
                if (alignedGoal >= gAddressBase)
1033
                {
1034
                        VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal,
1035
                                                 MEM_DECOMMIT);
1036
                        gNextAddress = gNextAddress + size;
1037
                        return (void*)gNextAddress;
1038
                }
1039
                else
1040
                {
1041
                        VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase,
1042
                                                 MEM_DECOMMIT);
1043
                        gNextAddress = gAddressBase;
1044
                        return (void*)-1;
1045
                }
1046
        }
1047
        else
1048
        {
1049
                return (void*)gNextAddress;
1050
        }
1051
}
1052
 
1053
#endif
1054
 
1055
 
1056
 
1057
/*
1058
  Type declarations
1059
*/
1060
 
1061
 
1062
struct malloc_chunk
1063
{
1064
  INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */
1065
  INTERNAL_SIZE_T size;      /* Size in bytes, including overhead. */
1066
  struct malloc_chunk* fd;   /* double links -- used only if free. */
1067
  struct malloc_chunk* bk;
1068
};
1069
 
1070
typedef struct malloc_chunk* mchunkptr;
1071
 
1072
/*
1073
 
1074
   malloc_chunk details:
1075
 
1076
    (The following includes lightly edited explanations by Colin Plumb.)
1077
 
1078
    Chunks of memory are maintained using a `boundary tag' method as
1079
    described in e.g., Knuth or Standish.  (See the paper by Paul
1080
    Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
1081
    survey of such techniques.)  Sizes of free chunks are stored both
1082
    in the front of each chunk and at the end.  This makes
1083
    consolidating fragmented chunks into bigger chunks very fast.  The
1084
    size fields also hold bits representing whether chunks are free or
1085
    in use.
1086
 
1087
    An allocated chunk looks like this:
1088
 
1089
 
1090
    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1091
            |             Size of previous chunk, if allocated            | |
1092
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1093
            |             Size of chunk, in bytes                         |P|
1094
      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1095
            |             User data starts here...                          .
1096
            .                                                               .
1097
            .             (malloc_usable_space() bytes)                     .
1098
            .                                                               |
1099
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1100
            |             Size of chunk                                     |
1101
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1102
 
1103
 
1104
    Where "chunk" is the front of the chunk for the purpose of most of
1105
    the malloc code, but "mem" is the pointer that is returned to the
1106
    user.  "Nextchunk" is the beginning of the next contiguous chunk.
1107
 
1108
    Chunks always begin on even word boundries, so the mem portion
1109
    (which is returned to the user) is also on an even word boundary, and
1110
    thus double-word aligned.
1111
 
1112
    Free chunks are stored in circular doubly-linked lists, and look like this:
1113
 
1114
    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1115
            |             Size of previous chunk                            |
1116
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1117
    `head:' |             Size of chunk, in bytes                         |P|
1118
      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1119
            |             Forward pointer to next chunk in list             |
1120
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1121
            |             Back pointer to previous chunk in list            |
1122
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1123
            |             Unused space (may be 0 bytes long)                .
1124
            .                                                               .
1125
            .                                                               |
1126
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1127
    `foot:' |             Size of chunk, in bytes                           |
1128
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1129
 
1130
    The P (PREV_INUSE) bit, stored in the unused low-order bit of the
1131
    chunk size (which is always a multiple of two words), is an in-use
1132
    bit for the *previous* chunk.  If that bit is *clear*, then the
1133
    word before the current chunk size contains the previous chunk
1134
    size, and can be used to find the front of the previous chunk.
1135
    (The very first chunk allocated always has this bit set,
1136
    preventing access to non-existent (or non-owned) memory.)
1137
 
1138
    Note that the `foot' of the current chunk is actually represented
1139
    as the prev_size of the NEXT chunk. (This makes it easier to
1140
    deal with alignments etc).
1141
 
1142
    The two exceptions to all this are
1143
 
1144
     1. The special chunk `top', which doesn't bother using the
1145
        trailing size field since there is no
1146
        next contiguous chunk that would have to index off it. (After
1147
        initialization, `top' is forced to always exist.  If it would
1148
        become less than MINSIZE bytes long, it is replenished via
1149
        malloc_extend_top.)
1150
 
1151
     2. Chunks allocated via mmap, which have the second-lowest-order
1152
        bit (IS_MMAPPED) set in their size fields.  Because they are
1153
        never merged or traversed from any other chunk, they have no
1154
        foot size or inuse information.
1155
 
1156
    Available chunks are kept in any of several places (all declared below):
1157
 
1158
    * `av': An array of chunks serving as bin headers for consolidated
1159
       chunks. Each bin is doubly linked.  The bins are approximately
1160
       proportionally (log) spaced.  There are a lot of these bins
1161
       (128). This may look excessive, but works very well in
1162
       practice.  All procedures maintain the invariant that no
1163
       consolidated chunk physically borders another one. Chunks in
1164
       bins are kept in size order, with ties going to the
1165
       approximately least recently used chunk.
1166
 
1167
       The chunks in each bin are maintained in decreasing sorted order by
1168
       size.  This is irrelevant for the small bins, which all contain
1169
       the same-sized chunks, but facilitates best-fit allocation for
1170
       larger chunks. (These lists are just sequential. Keeping them in
1171
       order almost never requires enough traversal to warrant using
1172
       fancier ordered data structures.)  Chunks of the same size are
1173
       linked with the most recently freed at the front, and allocations
1174
       are taken from the back.  This results in LRU or FIFO allocation
1175
       order, which tends to give each chunk an equal opportunity to be
1176
       consolidated with adjacent freed chunks, resulting in larger free
1177
       chunks and less fragmentation.
1178
 
1179
    * `top': The top-most available chunk (i.e., the one bordering the
1180
       end of available memory) is treated specially. It is never
1181
       included in any bin, is used only if no other chunk is
1182
       available, and is released back to the system if it is very
1183
       large (see M_TRIM_THRESHOLD).
1184
 
1185
    * `last_remainder': A bin holding only the remainder of the
1186
       most recently split (non-top) chunk. This bin is checked
1187
       before other non-fitting chunks, so as to provide better
1188
       locality for runs of sequentially allocated chunks.
1189
 
1190
    *  Implicitly, through the host system's memory mapping tables.
1191
       If supported, requests greater than a threshold are usually
1192
       serviced via calls to mmap, and then later released via munmap.
1193
 
1194
*/
1195
 
1196
 
1197
 
1198
 
1199
 
1200
 
1201
/*  sizes, alignments */
1202
 
1203
#define SIZE_SZ                (sizeof(INTERNAL_SIZE_T))
1204
#define MALLOC_ALIGNMENT       (SIZE_SZ + SIZE_SZ)
1205
#define MALLOC_ALIGN_MASK      (MALLOC_ALIGNMENT - 1)
1206
#define MINSIZE                (sizeof(struct malloc_chunk))
1207
 
1208
/* conversion from malloc headers to user pointers, and back */
1209
 
1210
#define chunk2mem(p)   ((Void_t*)((char*)(p) + 2*SIZE_SZ))
1211
#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
1212
 
1213
/* pad request bytes into a usable size */
1214
 
1215
#define request2size(req) \
1216
 (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
1217
  (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
1218
   (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
1219
 
1220
/* Check if m has acceptable alignment */
1221
 
1222
#define aligned_OK(m)    (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
1223
 
1224
 
1225
 
1226
 
1227
/*
1228
  Physical chunk operations
1229
*/
1230
 
1231
 
1232
/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
1233
 
1234
#define PREV_INUSE 0x1 
1235
 
1236
/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
1237
 
1238
#define IS_MMAPPED 0x2
1239
 
1240
/* Bits to mask off when extracting size */
1241
 
1242
#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
1243
 
1244
 
1245
/* Ptr to next physical malloc_chunk. */
1246
 
1247
#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))
1248
 
1249
/* Ptr to previous physical malloc_chunk */
1250
 
1251
#define prev_chunk(p)\
1252
   ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
1253
 
1254
 
1255
/* Treat space at ptr + offset as a chunk */
1256
 
1257
#define chunk_at_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
1258
 
1259
 
1260
 
1261
 
1262
/*
1263
  Dealing with use bits
1264
*/
1265
 
1266
/* extract p's inuse bit */
1267
 
1268
#define inuse(p)\
1269
((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)
1270
 
1271
/* extract inuse bit of previous chunk */
1272
 
1273
#define prev_inuse(p)  ((p)->size & PREV_INUSE)
1274
 
1275
/* check for mmap()'ed chunk */
1276
 
1277
#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
1278
 
1279
/* set/clear chunk as in use without otherwise disturbing */
1280
 
1281
#define set_inuse(p)\
1282
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE
1283
 
1284
#define clear_inuse(p)\
1285
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)
1286
 
1287
/* check/set/clear inuse bits in known places */
1288
 
1289
#define inuse_bit_at_offset(p, s)\
1290
 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
1291
 
1292
#define set_inuse_bit_at_offset(p, s)\
1293
 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
1294
 
1295
#define clear_inuse_bit_at_offset(p, s)\
1296
 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
1297
 
1298
 
1299
 
1300
 
1301
/*
1302
  Dealing with size fields
1303
*/
1304
 
1305
/* Get size, ignoring use bits */
1306
 
1307
#define chunksize(p)          ((p)->size & ~(SIZE_BITS))
1308
 
1309
/* Set size at head, without disturbing its use bit */
1310
 
1311
#define set_head_size(p, s)   ((p)->size = (((p)->size & PREV_INUSE) | (s)))
1312
 
1313
/* Set size/use ignoring previous bits in header */
1314
 
1315
#define set_head(p, s)        ((p)->size = (s))
1316
 
1317
/* Set size at footer (only when chunk is not in use) */
1318
 
1319
#define set_foot(p, s)   (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
1320
 
1321
 
1322
 
1323
 
1324
 
1325
/*
1326
   Bins
1327
 
1328
    The bins, `av_' are an array of pairs of pointers serving as the
1329
    heads of (initially empty) doubly-linked lists of chunks, laid out
1330
    in a way so that each pair can be treated as if it were in a
1331
    malloc_chunk. (This way, the fd/bk offsets for linking bin heads
1332
    and chunks are the same).
1333
 
1334
    Bins for sizes < 512 bytes contain chunks of all the same size, spaced
1335
    8 bytes apart. Larger bins are approximately logarithmically
1336
    spaced. (See the table below.) The `av_' array is never mentioned
1337
    directly in the code, but instead via bin access macros.
1338
 
1339
    Bin layout:
1340
 
1341
    64 bins of size       8
1342
    32 bins of size      64
1343
    16 bins of size     512
1344
     8 bins of size    4096
1345
     4 bins of size   32768
1346
     2 bins of size  262144
1347
     1 bin  of size what's left
1348
 
1349
    There is actually a little bit of slop in the numbers in bin_index
1350
    for the sake of speed. This makes no difference elsewhere.
1351
 
1352
    The special chunks `top' and `last_remainder' get their own bins,
1353
    (this is implemented via yet more trickery with the av_ array),
1354
    although `top' is never properly linked to its bin since it is
1355
    always handled specially.
1356
 
1357
*/
1358
 
1359
#define NAV             128   /* number of bins */
1360
 
1361
typedef struct malloc_chunk* mbinptr;
1362
 
1363
/* access macros */
1364
 
1365
#define bin_at(i)      ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
1366
#define next_bin(b)    ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
1367
#define prev_bin(b)    ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))
1368
 
1369
/*
1370
   The first 2 bins are never indexed. The corresponding av_ cells are instead
1371
   used for bookkeeping. This is not to save space, but to simplify
1372
   indexing, maintain locality, and avoid some initialization tests.
1373
*/
1374
 
1375
#define top            (bin_at(0)->fd)   /* The topmost chunk */
1376
#define last_remainder (bin_at(1))       /* remainder from last split */
1377
 
1378
 
1379
/*
1380
   Because top initially points to its own bin with initial
1381
   zero size, thus forcing extension on the first malloc request,
1382
   we avoid having any special code in malloc to check whether
1383
   it even exists yet. But we still need to in malloc_extend_top.
1384
*/
1385
 
1386
#define initial_top    ((mchunkptr)(bin_at(0)))
1387
 
1388
/* Helper macro to initialize bins */
1389
 
1390
#define IAV(i)  bin_at(i), bin_at(i)
1391
 
1392
static mbinptr av_[NAV * 2 + 2] = {
1393
 0, 0,
1394
 IAV(0),   IAV(1),   IAV(2),   IAV(3),   IAV(4),   IAV(5),   IAV(6),   IAV(7),
1395
 IAV(8),   IAV(9),   IAV(10),  IAV(11),  IAV(12),  IAV(13),  IAV(14),  IAV(15),
1396
 IAV(16),  IAV(17),  IAV(18),  IAV(19),  IAV(20),  IAV(21),  IAV(22),  IAV(23),
1397
 IAV(24),  IAV(25),  IAV(26),  IAV(27),  IAV(28),  IAV(29),  IAV(30),  IAV(31),
1398
 IAV(32),  IAV(33),  IAV(34),  IAV(35),  IAV(36),  IAV(37),  IAV(38),  IAV(39),
1399
 IAV(40),  IAV(41),  IAV(42),  IAV(43),  IAV(44),  IAV(45),  IAV(46),  IAV(47),
1400
 IAV(48),  IAV(49),  IAV(50),  IAV(51),  IAV(52),  IAV(53),  IAV(54),  IAV(55),
1401
 IAV(56),  IAV(57),  IAV(58),  IAV(59),  IAV(60),  IAV(61),  IAV(62),  IAV(63),
1402
 IAV(64),  IAV(65),  IAV(66),  IAV(67),  IAV(68),  IAV(69),  IAV(70),  IAV(71),
1403
 IAV(72),  IAV(73),  IAV(74),  IAV(75),  IAV(76),  IAV(77),  IAV(78),  IAV(79),
1404
 IAV(80),  IAV(81),  IAV(82),  IAV(83),  IAV(84),  IAV(85),  IAV(86),  IAV(87),
1405
 IAV(88),  IAV(89),  IAV(90),  IAV(91),  IAV(92),  IAV(93),  IAV(94),  IAV(95),
1406
 IAV(96),  IAV(97),  IAV(98),  IAV(99),  IAV(100), IAV(101), IAV(102), IAV(103),
1407
 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
1408
 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
1409
 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
1410
};
1411
 
1412
 
1413
 
1414
/* field-extraction macros */
1415
 
1416
#define first(b) ((b)->fd)
1417
#define last(b)  ((b)->bk)
1418
 
1419
/*
1420
  Indexing into bins
1421
*/
1422
 
1423
#define bin_index(sz)                                                          \
1424
(((((unsigned long)(sz)) >> 9) ==    0) ?       (((unsigned long)(sz)) >>  3): \
1425
 ((((unsigned long)(sz)) >> 9) <=    4) ?  56 + (((unsigned long)(sz)) >>  6): \
1426
 ((((unsigned long)(sz)) >> 9) <=   20) ?  91 + (((unsigned long)(sz)) >>  9): \
1427
 ((((unsigned long)(sz)) >> 9) <=   84) ? 110 + (((unsigned long)(sz)) >> 12): \
1428
 ((((unsigned long)(sz)) >> 9) <=  340) ? 119 + (((unsigned long)(sz)) >> 15): \
1429
 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
1430
                                          126)
1431
/*
1432
  bins for chunks < 512 are all spaced 8 bytes apart, and hold
1433
  identically sized chunks. This is exploited in malloc.
1434
*/
1435
 
1436
#define MAX_SMALLBIN         63
1437
#define MAX_SMALLBIN_SIZE   512
1438
#define SMALLBIN_WIDTH        8
1439
 
1440
#define smallbin_index(sz)  (((unsigned long)(sz)) >> 3)
1441
 
1442
/*
1443
   Requests are `small' if both the corresponding and the next bin are small
1444
*/
1445
 
1446
#define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)
1447
 
1448
 
1449
 
1450
/*
1451
    To help compensate for the large number of bins, a one-level index
1452
    structure is used for bin-by-bin searching.  `binblocks' is a
1453
    one-word bitvector recording whether groups of BINBLOCKWIDTH bins
1454
    have any (possibly) non-empty bins, so they can be skipped over
1455
    all at once during during traversals. The bits are NOT always
1456
    cleared as soon as all bins in a block are empty, but instead only
1457
    when all are noticed to be empty during traversal in malloc.
1458
*/
1459
 
1460
#define BINBLOCKWIDTH     4   /* bins per block */
1461
 
1462
#define binblocks      (bin_at(0)->size) /* bitvector of nonempty blocks */
1463
 
1464
/* bin<->block macros */
1465
 
1466
#define idx2binblock(ix)    ((unsigned)1 << (ix / BINBLOCKWIDTH))
1467
#define mark_binblock(ii)   (binblocks |= idx2binblock(ii))
1468
#define clear_binblock(ii)  (binblocks &= ~(idx2binblock(ii)))
1469
 
1470
 
1471
 
1472
 
1473
 
1474
/*  Other static bookkeeping data */
1475
 
1476
/* variables holding tunable values */
1477
 
1478
static unsigned long trim_threshold   = DEFAULT_TRIM_THRESHOLD;
1479
static unsigned long top_pad          = DEFAULT_TOP_PAD;
1480
static unsigned int  n_mmaps_max      = DEFAULT_MMAP_MAX;
1481
static unsigned long mmap_threshold   = DEFAULT_MMAP_THRESHOLD;
1482
 
1483
/* The first value returned from sbrk */
1484
static char* sbrk_base = (char*)(-1);
1485
 
1486
/* The maximum memory obtained from system via sbrk */
1487
static unsigned long max_sbrked_mem = 0;
1488
 
1489
/* The maximum via either sbrk or mmap */
1490
static unsigned long max_total_mem = 0;
1491
 
1492
/* internal working copy of mallinfo */
1493
static struct mallinfo current_mallinfo = {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
1494
 
1495
/* The total memory obtained from system via sbrk */
1496
#define sbrked_mem  (current_mallinfo.arena)
1497
 
1498
/* Tracking mmaps */
1499
 
1500
static unsigned int n_mmaps = 0;
1501
static unsigned int max_n_mmaps = 0;
1502
static unsigned long mmapped_mem = 0;
1503
static unsigned long max_mmapped_mem = 0;
1504
 
1505
 
1506
 
1507
/*
1508
  Debugging support
1509
*/
1510
 
1511
#if DEBUG
1512
 
1513
 
1514
/*
1515
  These routines make a number of assertions about the states
1516
  of data structures that should be true at all times. If any
1517
  are not true, it's very likely that a user program has somehow
1518
  trashed memory. (It's also possible that there is a coding error
1519
  in malloc. In which case, please report it!)
1520
*/
1521
 
1522
#if __STD_C
1523
static void do_check_chunk(mchunkptr p)
1524
#else
1525
static void do_check_chunk(p) mchunkptr p;
1526
#endif
1527
{
1528
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1529
 
1530
  /* No checkable chunk is mmapped */
1531
  assert(!chunk_is_mmapped(p));
1532
 
1533
  /* Check for legal address ... */
1534
  assert((char*)p >= sbrk_base);
1535
  if (p != top)
1536
    assert((char*)p + sz <= (char*)top);
1537
  else
1538
    assert((char*)p + sz <= sbrk_base + sbrked_mem);
1539
 
1540
}
1541
 
1542
 
1543
#if __STD_C
1544
static void do_check_free_chunk(mchunkptr p)
1545
#else
1546
static void do_check_free_chunk(p) mchunkptr p;
1547
#endif
1548
{
1549
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1550
  mchunkptr next = chunk_at_offset(p, sz);
1551
 
1552
  do_check_chunk(p);
1553
 
1554
  /* Check whether it claims to be free ... */
1555
  assert(!inuse(p));
1556
 
1557
  /* Unless a special marker, must have OK fields */
1558
  if ((long)sz >= (long)MINSIZE)
1559
  {
1560
    assert((sz & MALLOC_ALIGN_MASK) == 0);
1561
    assert(aligned_OK(chunk2mem(p)));
1562
    /* ... matching footer field */
1563
    assert(next->prev_size == sz);
1564
    /* ... and is fully consolidated */
1565
    assert(prev_inuse(p));
1566
    assert (next == top || inuse(next));
1567
 
1568
    /* ... and has minimally sane links */
1569
    assert(p->fd->bk == p);
1570
    assert(p->bk->fd == p);
1571
  }
1572
  else /* markers are always of size SIZE_SZ */
1573
    assert(sz == SIZE_SZ);
1574
}
1575
 
1576
#if __STD_C
1577
static void do_check_inuse_chunk(mchunkptr p)
1578
#else
1579
static void do_check_inuse_chunk(p) mchunkptr p;
1580
#endif
1581
{
1582
  mchunkptr next = next_chunk(p);
1583
  do_check_chunk(p);
1584
 
1585
  /* Check whether it claims to be in use ... */
1586
  assert(inuse(p));
1587
 
1588
  /* ... and is surrounded by OK chunks.
1589
    Since more things can be checked with free chunks than inuse ones,
1590
    if an inuse chunk borders them and debug is on, it's worth doing them.
1591
  */
1592
  if (!prev_inuse(p))
1593
  {
1594
    mchunkptr prv = prev_chunk(p);
1595
    assert(next_chunk(prv) == p);
1596
    do_check_free_chunk(prv);
1597
  }
1598
  if (next == top)
1599
  {
1600
    assert(prev_inuse(next));
1601
    assert(chunksize(next) >= MINSIZE);
1602
  }
1603
  else if (!inuse(next))
1604
    do_check_free_chunk(next);
1605
 
1606
}
1607
 
1608
#if __STD_C
1609
static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
1610
#else
1611
static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
1612
#endif
1613
{
1614
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1615
  long room = sz - s;
1616
 
1617
  do_check_inuse_chunk(p);
1618
 
1619
  /* Legal size ... */
1620
  assert((long)sz >= (long)MINSIZE);
1621
  assert((sz & MALLOC_ALIGN_MASK) == 0);
1622
  assert(room >= 0);
1623
  assert(room < (long)MINSIZE);
1624
 
1625
  /* ... and alignment */
1626
  assert(aligned_OK(chunk2mem(p)));
1627
 
1628
 
1629
  /* ... and was allocated at front of an available chunk */
1630
  assert(prev_inuse(p));
1631
 
1632
}
1633
 
1634
 
1635
#define check_free_chunk(P)  do_check_free_chunk(P)
1636
#define check_inuse_chunk(P) do_check_inuse_chunk(P)
1637
#define check_chunk(P) do_check_chunk(P)
1638
#define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N)
1639
#else
1640
#define check_free_chunk(P) 
1641
#define check_inuse_chunk(P)
1642
#define check_chunk(P)
1643
#define check_malloced_chunk(P,N)
1644
#endif
1645
 
1646
 
1647
 
1648
/*
1649
  Macro-based internal utilities
1650
*/
1651
 
1652
 
1653
/*
1654
  Linking chunks in bin lists.
1655
  Call these only with variables, not arbitrary expressions, as arguments.
1656
*/
1657
 
1658
/*
1659
  Place chunk p of size s in its bin, in size order,
1660
  putting it ahead of others of same size.
1661
*/
1662
 
1663
 
1664
#define frontlink(P, S, IDX, BK, FD)                                          \
1665
{                                                                             \
1666
  if (S < MAX_SMALLBIN_SIZE)                                                  \
1667
  {                                                                           \
1668
    IDX = smallbin_index(S);                                                  \
1669
    mark_binblock(IDX);                                                       \
1670
    BK = bin_at(IDX);                                                         \
1671
    FD = BK->fd;                                                              \
1672
    P->bk = BK;                                                               \
1673
    P->fd = FD;                                                               \
1674
    FD->bk = BK->fd = P;                                                      \
1675
  }                                                                           \
1676
  else                                                                        \
1677
  {                                                                           \
1678
    IDX = bin_index(S);                                                       \
1679
    BK = bin_at(IDX);                                                         \
1680
    FD = BK->fd;                                                              \
1681
    if (FD == BK) mark_binblock(IDX);                                         \
1682
    else                                                                      \
1683
    {                                                                         \
1684
      while (FD != BK && S < chunksize(FD)) FD = FD->fd;                      \
1685
      BK = FD->bk;                                                            \
1686
    }                                                                         \
1687
    P->bk = BK;                                                               \
1688
    P->fd = FD;                                                               \
1689
    FD->bk = BK->fd = P;                                                      \
1690
  }                                                                           \
1691
}
1692
 
1693
 
1694
/* take a chunk off a list */
1695
 
1696
#define unlink(P, BK, FD)                                                     \
1697
{                                                                             \
1698
  BK = P->bk;                                                                 \
1699
  FD = P->fd;                                                                 \
1700
  FD->bk = BK;                                                                \
1701
  BK->fd = FD;                                                                \
1702
}                                                                             \
1703
 
1704
/* Place p as the last remainder */
1705
 
1706
#define link_last_remainder(P)                                                \
1707
{                                                                             \
1708
  last_remainder->fd = last_remainder->bk =  P;                               \
1709
  P->fd = P->bk = last_remainder;                                             \
1710
}
1711
 
1712
/* Clear the last_remainder bin */
1713
 
1714
#define clear_last_remainder \
1715
  (last_remainder->fd = last_remainder->bk = last_remainder)
1716
 
1717
 
1718
 
1719
 
1720
 
1721
 
1722
/* Routines dealing with mmap(). */
1723
 
1724
#if HAVE_MMAP
1725
 
1726
#if __STD_C
1727
static mchunkptr mmap_chunk(size_t size)
1728
#else
1729
static mchunkptr mmap_chunk(size) size_t size;
1730
#endif
1731
{
1732
  size_t page_mask = malloc_getpagesize - 1;
1733
  mchunkptr p;
1734
 
1735
#ifndef MAP_ANONYMOUS
1736
  static int fd = -1;
1737
#endif
1738
 
1739
  if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */
1740
 
1741
  /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
1742
   * there is no following chunk whose prev_size field could be used.
1743
   */
1744
  size = (size + SIZE_SZ + page_mask) & ~page_mask;
1745
 
1746
#ifdef MAP_ANONYMOUS
1747
  p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE,
1748
                      MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
1749
#else /* !MAP_ANONYMOUS */
1750
  if (fd < 0)
1751
  {
1752
    fd = open("/dev/zero", O_RDWR);
1753
    if(fd < 0) return 0;
1754
  }
1755
  p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
1756
#endif
1757
 
1758
  if(p == (mchunkptr)-1) return 0;
1759
 
1760
  n_mmaps++;
1761
  if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;
1762
 
1763
  /* We demand that eight bytes into a page must be 8-byte aligned. */
1764
  assert(aligned_OK(chunk2mem(p)));
1765
 
1766
  /* The offset to the start of the mmapped region is stored
1767
   * in the prev_size field of the chunk; normally it is zero,
1768
   * but that can be changed in memalign().
1769
   */
1770
  p->prev_size = 0;
1771
  set_head(p, size|IS_MMAPPED);
1772
 
1773
  mmapped_mem += size;
1774
  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1775
    max_mmapped_mem = mmapped_mem;
1776
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1777
    max_total_mem = mmapped_mem + sbrked_mem;
1778
  return p;
1779
}
1780
 
1781
#if __STD_C
1782
static void munmap_chunk(mchunkptr p)
1783
#else
1784
static void munmap_chunk(p) mchunkptr p;
1785
#endif
1786
{
1787
  INTERNAL_SIZE_T size = chunksize(p);
1788
  int ret;
1789
 
1790
  assert (chunk_is_mmapped(p));
1791
  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1792
  assert((n_mmaps > 0));
1793
  assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);
1794
 
1795
  n_mmaps--;
1796
  mmapped_mem -= (size + p->prev_size);
1797
 
1798
  ret = munmap((char *)p - p->prev_size, size + p->prev_size);
1799
 
1800
  /* munmap returns non-zero on failure */
1801
  assert(ret == 0);
1802
}
1803
 
1804
#if HAVE_MREMAP
1805
 
1806
#if __STD_C
1807
static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
1808
#else
1809
static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
1810
#endif
1811
{
1812
  size_t page_mask = malloc_getpagesize - 1;
1813
  INTERNAL_SIZE_T offset = p->prev_size;
1814
  INTERNAL_SIZE_T size = chunksize(p);
1815
  char *cp;
1816
 
1817
  assert (chunk_is_mmapped(p));
1818
  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1819
  assert((n_mmaps > 0));
1820
  assert(((size + offset) & (malloc_getpagesize-1)) == 0);
1821
 
1822
  /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
1823
  new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;
1824
 
1825
  cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1);
1826
 
1827
  if (cp == (char *)-1) return 0;
1828
 
1829
  p = (mchunkptr)(cp + offset);
1830
 
1831
  assert(aligned_OK(chunk2mem(p)));
1832
 
1833
  assert((p->prev_size == offset));
1834
  set_head(p, (new_size - offset)|IS_MMAPPED);
1835
 
1836
  mmapped_mem -= size + offset;
1837
  mmapped_mem += new_size;
1838
  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1839
    max_mmapped_mem = mmapped_mem;
1840
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1841
    max_total_mem = mmapped_mem + sbrked_mem;
1842
  return p;
1843
}
1844
 
1845
#endif /* HAVE_MREMAP */
1846
 
1847
#endif /* HAVE_MMAP */
1848
 
1849
 
1850
 
1851
 
1852
/*
1853
  Extend the top-most chunk by obtaining memory from system.
1854
  Main interface to sbrk (but see also malloc_trim).
1855
*/
1856
 
1857
#if __STD_C
1858
static void malloc_extend_top(INTERNAL_SIZE_T nb)
1859
#else
1860
static void malloc_extend_top(nb) INTERNAL_SIZE_T nb;
1861
#endif
1862
{
1863
  char*     brk;                  /* return value from sbrk */
1864
  INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
1865
  INTERNAL_SIZE_T correction;     /* bytes for 2nd sbrk call */
1866
  char*     new_brk;              /* return of 2nd sbrk call */
1867
  INTERNAL_SIZE_T top_size;       /* new size of top chunk */
1868
 
1869
  mchunkptr old_top     = top;  /* Record state of old top */
1870
  INTERNAL_SIZE_T old_top_size = chunksize(old_top);
1871
  char*     old_end      = (char*)(chunk_at_offset(old_top, old_top_size));
1872
 
1873
  /* Pad request with top_pad plus minimal overhead */
1874
 
1875
  INTERNAL_SIZE_T    sbrk_size     = nb + top_pad + MINSIZE;
1876
  unsigned long pagesz    = malloc_getpagesize;
1877
 
1878
  /* If not the first time through, round to preserve page boundary */
1879
  /* Otherwise, we need to correct to a page size below anyway. */
1880
  /* (We also correct below if an intervening foreign sbrk call.) */
1881
 
1882
  if (sbrk_base != (char*)(-1))
1883
    sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1);
1884
 
1885
  brk = (char*)(MORECORE (sbrk_size));
1886
 
1887
  /* Fail if sbrk failed or if a foreign sbrk call killed our space */
1888
  if (brk == (char*)(MORECORE_FAILURE) ||
1889
      (brk < old_end && old_top != initial_top))
1890
    return;
1891
 
1892
  sbrked_mem += sbrk_size;
1893
 
1894
  if (brk == old_end) /* can just add bytes to current top */
1895
  {
1896
    top_size = sbrk_size + old_top_size;
1897
    set_head(top, top_size | PREV_INUSE);
1898
  }
1899
  else
1900
  {
1901
    if (sbrk_base == (char*)(-1))  /* First time through. Record base */
1902
      sbrk_base = brk;
1903
    else  /* Someone else called sbrk().  Count those bytes as sbrked_mem. */
1904
      sbrked_mem += brk - (char*)old_end;
1905
 
1906
    /* Guarantee alignment of first new chunk made from this space */
1907
    front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
1908
    if (front_misalign > 0)
1909
    {
1910
      correction = (MALLOC_ALIGNMENT) - front_misalign;
1911
      brk += correction;
1912
    }
1913
    else
1914
      correction = 0;
1915
 
1916
    /* Guarantee the next brk will be at a page boundary */
1917
    correction += pagesz - ((unsigned long)(brk + sbrk_size) & (pagesz - 1));
1918
 
1919
    /* Allocate correction */
1920
    new_brk = (char*)(MORECORE (correction));
1921
    if (new_brk == (char*)(MORECORE_FAILURE)) return;
1922
 
1923
    sbrked_mem += correction;
1924
 
1925
    top = (mchunkptr)brk;
1926
    top_size = new_brk - brk + correction;
1927
    set_head(top, top_size | PREV_INUSE);
1928
 
1929
    if (old_top != initial_top)
1930
    {
1931
 
1932
      /* There must have been an intervening foreign sbrk call. */
1933
      /* A double fencepost is necessary to prevent consolidation */
1934
 
1935
      /* If not enough space to do this, then user did something very wrong */
1936
      if (old_top_size < MINSIZE)
1937
      {
1938
        set_head(top, PREV_INUSE); /* will force null return from malloc */
1939
        return;
1940
      }
1941
 
1942
      /* Also keep size a multiple of MALLOC_ALIGNMENT */
1943
      old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
1944
      chunk_at_offset(old_top, old_top_size          )->size =
1945
        SIZE_SZ|PREV_INUSE;
1946
      chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size =
1947
        SIZE_SZ|PREV_INUSE;
1948
      set_head_size(old_top, old_top_size);
1949
      /* If possible, release the rest. */
1950
      if (old_top_size >= MINSIZE)
1951
        fREe(chunk2mem(old_top));
1952
    }
1953
  }
1954
 
1955
  if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
1956
    max_sbrked_mem = sbrked_mem;
1957
  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1958
    max_total_mem = mmapped_mem + sbrked_mem;
1959
 
1960
  /* We always land on a page boundary */
1961
  assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0);
1962
}
1963
 
1964
 
1965
 
1966
 
1967
/* Main public routines */
1968
 
1969
 
1970
/*
1971
  Malloc Algorthim:
1972
 
1973
    The requested size is first converted into a usable form, `nb'.
1974
    This currently means to add 4 bytes overhead plus possibly more to
1975
    obtain 8-byte alignment and/or to obtain a size of at least
1976
    MINSIZE (currently 16 bytes), the smallest allocatable size.
1977
    (All fits are considered `exact' if they are within MINSIZE bytes.)
1978
 
1979
    From there, the first successful of the following steps is taken:
1980
 
1981
      1. The bin corresponding to the request size is scanned, and if
1982
         a chunk of exactly the right size is found, it is taken.
1983
 
1984
      2. The most recently remaindered chunk is used if it is big
1985
         enough.  This is a form of (roving) first fit, used only in
1986
         the absence of exact fits. Runs of consecutive requests use
1987
         the remainder of the chunk used for the previous such request
1988
         whenever possible. This limited use of a first-fit style
1989
         allocation strategy tends to give contiguous chunks
1990
         coextensive lifetimes, which improves locality and can reduce
1991
         fragmentation in the long run.
1992
 
1993
      3. Other bins are scanned in increasing size order, using a
1994
         chunk big enough to fulfill the request, and splitting off
1995
         any remainder.  This search is strictly by best-fit; i.e.,
1996
         the smallest (with ties going to approximately the least
1997
         recently used) chunk that fits is selected.
1998
 
1999
      4. If large enough, the chunk bordering the end of memory
2000
         (`top') is split off. (This use of `top' is in accord with
2001
         the best-fit search rule.  In effect, `top' is treated as
2002
         larger (and thus less well fitting) than any other available
2003
         chunk since it can be extended to be as large as necessary
2004
         (up to system limitations).
2005
 
2006
      5. If the request size meets the mmap threshold and the
2007
         system supports mmap, and there are few enough currently
2008
         allocated mmapped regions, and a call to mmap succeeds,
2009
         the request is allocated via direct memory mapping.
2010
 
2011
      6. Otherwise, the top of memory is extended by
2012
         obtaining more space from the system (normally using sbrk,
2013
         but definable to anything else via the MORECORE macro).
2014
         Memory is gathered from the system (in system page-sized
2015
         units) in a way that allows chunks obtained across different
2016
         sbrk calls to be consolidated, but does not require
2017
         contiguous memory. Thus, it should be safe to intersperse
2018
         mallocs with other sbrk calls.
2019
 
2020
 
2021
      All allocations are made from the the `lowest' part of any found
2022
      chunk. (The implementation invariant is that prev_inuse is
2023
      always true of any allocated chunk; i.e., that each allocated
2024
      chunk borders either a previously allocated and still in-use chunk,
2025
      or the base of its memory arena.)
2026
 
2027
*/
2028
 
2029
#if __STD_C
2030
Void_t* mALLOc(size_t bytes)
2031
#else
2032
Void_t* mALLOc(bytes) size_t bytes;
2033
#endif
2034
{
2035
  mchunkptr victim;                  /* inspected/selected chunk */
2036
  INTERNAL_SIZE_T victim_size;       /* its size */
2037
  int       idx;                     /* index for bin traversal */
2038
  mbinptr   bin;                     /* associated bin */
2039
  mchunkptr remainder;               /* remainder from a split */
2040
  long      remainder_size;          /* its size */
2041
  int       remainder_index;         /* its bin index */
2042
  unsigned long block;               /* block traverser bit */
2043
  int       startidx;                /* first bin of a traversed block */
2044
  mchunkptr fwd;                     /* misc temp for linking */
2045
  mchunkptr bck;                     /* misc temp for linking */
2046
  mbinptr q;                         /* misc temp */
2047
 
2048
  INTERNAL_SIZE_T nb  = request2size(bytes);  /* padded request size; */
2049
 
2050
  /* Check for exact match in a bin */
2051
 
2052
  if (is_small_request(nb))  /* Faster version for small requests */
2053
  {
2054
    idx = smallbin_index(nb);
2055
 
2056
    /* No traversal or size check necessary for small bins.  */
2057
 
2058
    q = bin_at(idx);
2059
    victim = last(q);
2060
 
2061
    /* Also scan the next one, since it would have a remainder < MINSIZE */
2062
    if (victim == q)
2063
    {
2064
      q = next_bin(q);
2065
      victim = last(q);
2066
    }
2067
    if (victim != q)
2068
    {
2069
      victim_size = chunksize(victim);
2070
      unlink(victim, bck, fwd);
2071
      set_inuse_bit_at_offset(victim, victim_size);
2072
      check_malloced_chunk(victim, nb);
2073
      return chunk2mem(victim);
2074
    }
2075
 
2076
    idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */
2077
 
2078
  }
2079
  else
2080
  {
2081
    idx = bin_index(nb);
2082
    bin = bin_at(idx);
2083
 
2084
    for (victim = last(bin); victim != bin; victim = victim->bk)
2085
    {
2086
      victim_size = chunksize(victim);
2087
      remainder_size = victim_size - nb;
2088
 
2089
      if (remainder_size >= (long)MINSIZE) /* too big */
2090
      {
2091
        --idx; /* adjust to rescan below after checking last remainder */
2092
        break;
2093
      }
2094
 
2095
      else if (remainder_size >= 0) /* exact fit */
2096
      {
2097
        unlink(victim, bck, fwd);
2098
        set_inuse_bit_at_offset(victim, victim_size);
2099
        check_malloced_chunk(victim, nb);
2100
        return chunk2mem(victim);
2101
      }
2102
    }
2103
 
2104
    ++idx;
2105
 
2106
  }
2107
 
2108
  /* Try to use the last split-off remainder */
2109
 
2110
  if ( (victim = last_remainder->fd) != last_remainder)
2111
  {
2112
    victim_size = chunksize(victim);
2113
    remainder_size = victim_size - nb;
2114
 
2115
    if (remainder_size >= (long)MINSIZE) /* re-split */
2116
    {
2117
      remainder = chunk_at_offset(victim, nb);
2118
      set_head(victim, nb | PREV_INUSE);
2119
      link_last_remainder(remainder);
2120
      set_head(remainder, remainder_size | PREV_INUSE);
2121
      set_foot(remainder, remainder_size);
2122
      check_malloced_chunk(victim, nb);
2123
      return chunk2mem(victim);
2124
    }
2125
 
2126
    clear_last_remainder;
2127
 
2128
    if (remainder_size >= 0)  /* exhaust */
2129
    {
2130
      set_inuse_bit_at_offset(victim, victim_size);
2131
      check_malloced_chunk(victim, nb);
2132
      return chunk2mem(victim);
2133
    }
2134
 
2135
    /* Else place in bin */
2136
 
2137
    frontlink(victim, victim_size, remainder_index, bck, fwd);
2138
  }
2139
 
2140
  /*
2141
     If there are any possibly nonempty big-enough blocks,
2142
     search for best fitting chunk by scanning bins in blockwidth units.
2143
  */
2144
 
2145
  if ( (block = idx2binblock(idx)) <= binblocks)
2146
  {
2147
 
2148
    /* Get to the first marked block */
2149
 
2150
    if ( (block & binblocks) == 0)
2151
    {
2152
      /* force to an even block boundary */
2153
      idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
2154
      block <<= 1;
2155
      while ((block & binblocks) == 0)
2156
      {
2157
        idx += BINBLOCKWIDTH;
2158
        block <<= 1;
2159
      }
2160
    }
2161
 
2162
    /* For each possibly nonempty block ... */
2163
    for (;;)
2164
    {
2165
      startidx = idx;          /* (track incomplete blocks) */
2166
      q = bin = bin_at(idx);
2167
 
2168
      /* For each bin in this block ... */
2169
      do
2170
      {
2171
        /* Find and use first big enough chunk ... */
2172
 
2173
        for (victim = last(bin); victim != bin; victim = victim->bk)
2174
        {
2175
          victim_size = chunksize(victim);
2176
          remainder_size = victim_size - nb;
2177
 
2178
          if (remainder_size >= (long)MINSIZE) /* split */
2179
          {
2180
            remainder = chunk_at_offset(victim, nb);
2181
            set_head(victim, nb | PREV_INUSE);
2182
            unlink(victim, bck, fwd);
2183
            link_last_remainder(remainder);
2184
            set_head(remainder, remainder_size | PREV_INUSE);
2185
            set_foot(remainder, remainder_size);
2186
            check_malloced_chunk(victim, nb);
2187
            return chunk2mem(victim);
2188
          }
2189
 
2190
          else if (remainder_size >= 0)  /* take */
2191
          {
2192
            set_inuse_bit_at_offset(victim, victim_size);
2193
            unlink(victim, bck, fwd);
2194
            check_malloced_chunk(victim, nb);
2195
            return chunk2mem(victim);
2196
          }
2197
 
2198
        }
2199
 
2200
       bin = next_bin(bin);
2201
 
2202
      } while ((++idx & (BINBLOCKWIDTH - 1)) != 0);
2203
 
2204
      /* Clear out the block bit. */
2205
 
2206
      do   /* Possibly backtrack to try to clear a partial block */
2207
      {
2208
        if ((startidx & (BINBLOCKWIDTH - 1)) == 0)
2209
        {
2210
          binblocks &= ~block;
2211
          break;
2212
        }
2213
        --startidx;
2214
       q = prev_bin(q);
2215
      } while (first(q) == q);
2216
 
2217
      /* Get to the next possibly nonempty block */
2218
 
2219
      if ( (block <<= 1) <= binblocks && (block != 0) )
2220
      {
2221
        while ((block & binblocks) == 0)
2222
        {
2223
          idx += BINBLOCKWIDTH;
2224
          block <<= 1;
2225
        }
2226
      }
2227
      else
2228
        break;
2229
    }
2230
  }
2231
 
2232
 
2233
  /* Try to use top chunk */
2234
 
2235
  /* Require that there be a remainder, ensuring top always exists  */
2236
  if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
2237
  {
2238
 
2239
#if HAVE_MMAP
2240
    /* If big and would otherwise need to extend, try to use mmap instead */
2241
    if ((unsigned long)nb >= (unsigned long)mmap_threshold &&
2242
        (victim = mmap_chunk(nb)) != 0)
2243
      return chunk2mem(victim);
2244
#endif
2245
 
2246
    /* Try to extend */
2247
    malloc_extend_top(nb);
2248
    if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
2249
      return 0; /* propagate failure */
2250
  }
2251
 
2252
  victim = top;
2253
  set_head(victim, nb | PREV_INUSE);
2254
  top = chunk_at_offset(victim, nb);
2255
  set_head(top, remainder_size | PREV_INUSE);
2256
  check_malloced_chunk(victim, nb);
2257
  return chunk2mem(victim);
2258
 
2259
}
2260
 
2261
 
2262
 
2263
 
2264
/*
2265
 
2266
  free() algorithm :
2267
 
2268
    cases:
2269
 
2270
       1. free(0) has no effect.
2271
 
2272
       2. If the chunk was allocated via mmap, it is release via munmap().
2273
 
2274
       3. If a returned chunk borders the current high end of memory,
2275
          it is consolidated into the top, and if the total unused
2276
          topmost memory exceeds the trim threshold, malloc_trim is
2277
          called.
2278
 
2279
       4. Other chunks are consolidated as they arrive, and
2280
          placed in corresponding bins. (This includes the case of
2281
          consolidating with the current `last_remainder').
2282
 
2283
*/
2284
 
2285
 
2286
#if __STD_C
2287
void fREe(Void_t* mem)
2288
#else
2289
void fREe(mem) Void_t* mem;
2290
#endif
2291
{
2292
  mchunkptr p;         /* chunk corresponding to mem */
2293
  INTERNAL_SIZE_T hd;  /* its head field */
2294
  INTERNAL_SIZE_T sz;  /* its size */
2295
  int       idx;       /* its bin index */
2296
  mchunkptr next;      /* next contiguous chunk */
2297
  INTERNAL_SIZE_T nextsz; /* its size */
2298
  INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */
2299
  mchunkptr bck;       /* misc temp for linking */
2300
  mchunkptr fwd;       /* misc temp for linking */
2301
  int       islr;      /* track whether merging with last_remainder */
2302
 
2303
  if (mem == 0)                              /* free(0) has no effect */
2304
    return;
2305
 
2306
  p = mem2chunk(mem);
2307
  hd = p->size;
2308
 
2309
#if HAVE_MMAP
2310
  if (hd & IS_MMAPPED)                       /* release mmapped memory. */
2311
  {
2312
    munmap_chunk(p);
2313
    return;
2314
  }
2315
#endif
2316
 
2317
  check_inuse_chunk(p);
2318
 
2319
  sz = hd & ~PREV_INUSE;
2320
  next = chunk_at_offset(p, sz);
2321
  nextsz = chunksize(next);
2322
 
2323
  if (next == top)                            /* merge with top */
2324
  {
2325
    sz += nextsz;
2326
 
2327
    if (!(hd & PREV_INUSE))                    /* consolidate backward */
2328
    {
2329
      prevsz = p->prev_size;
2330
      p = chunk_at_offset(p, -prevsz);
2331
      sz += prevsz;
2332
      unlink(p, bck, fwd);
2333
    }
2334
 
2335
    set_head(p, sz | PREV_INUSE);
2336
    top = p;
2337
    if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
2338
      malloc_trim(top_pad);
2339
    return;
2340
  }
2341
 
2342
  set_head(next, nextsz);                    /* clear inuse bit */
2343
 
2344
  islr = 0;
2345
 
2346
  if (!(hd & PREV_INUSE))                    /* consolidate backward */
2347
  {
2348
    prevsz = p->prev_size;
2349
    p = chunk_at_offset(p, -prevsz);
2350
    sz += prevsz;
2351
 
2352
    if (p->fd == last_remainder)             /* keep as last_remainder */
2353
      islr = 1;
2354
    else
2355
      unlink(p, bck, fwd);
2356
  }
2357
 
2358
  if (!(inuse_bit_at_offset(next, nextsz)))   /* consolidate forward */
2359
  {
2360
    sz += nextsz;
2361
 
2362
    if (!islr && next->fd == last_remainder)  /* re-insert last_remainder */
2363
    {
2364
      islr = 1;
2365
      link_last_remainder(p);
2366
    }
2367
    else
2368
      unlink(next, bck, fwd);
2369
  }
2370
 
2371
 
2372
  set_head(p, sz | PREV_INUSE);
2373
  set_foot(p, sz);
2374
  if (!islr)
2375
    frontlink(p, sz, idx, bck, fwd);
2376
}
2377
 
2378
 
2379
 
2380
 
2381
 
2382
/*
2383
 
2384
  Realloc algorithm:
2385
 
2386
    Chunks that were obtained via mmap cannot be extended or shrunk
2387
    unless HAVE_MREMAP is defined, in which case mremap is used.
2388
    Otherwise, if their reallocation is for additional space, they are
2389
    copied.  If for less, they are just left alone.
2390
 
2391
    Otherwise, if the reallocation is for additional space, and the
2392
    chunk can be extended, it is, else a malloc-copy-free sequence is
2393
    taken.  There are several different ways that a chunk could be
2394
    extended. All are tried:
2395
 
2396
       * Extending forward into following adjacent free chunk.
2397
       * Shifting backwards, joining preceding adjacent space
2398
       * Both shifting backwards and extending forward.
2399
       * Extending into newly sbrked space
2400
 
2401
    Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
2402
    size argument of zero (re)allocates a minimum-sized chunk.
2403
 
2404
    If the reallocation is for less space, and the new request is for
2405
    a `small' (<512 bytes) size, then the newly unused space is lopped
2406
    off and freed.
2407
 
2408
    The old unix realloc convention of allowing the last-free'd chunk
2409
    to be used as an argument to realloc is no longer supported.
2410
    I don't know of any programs still relying on this feature,
2411
    and allowing it would also allow too many other incorrect
2412
    usages of realloc to be sensible.
2413
 
2414
 
2415
*/
2416
 
2417
 
2418
#if __STD_C
2419
Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
2420
#else
2421
Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
2422
#endif
2423
{
2424
  INTERNAL_SIZE_T    nb;      /* padded request size */
2425
 
2426
  mchunkptr oldp;             /* chunk corresponding to oldmem */
2427
  INTERNAL_SIZE_T    oldsize; /* its size */
2428
 
2429
  mchunkptr newp;             /* chunk to return */
2430
  INTERNAL_SIZE_T    newsize; /* its size */
2431
  Void_t*   newmem;           /* corresponding user mem */
2432
 
2433
  mchunkptr next;             /* next contiguous chunk after oldp */
2434
  INTERNAL_SIZE_T  nextsize;  /* its size */
2435
 
2436
  mchunkptr prev;             /* previous contiguous chunk before oldp */
2437
  INTERNAL_SIZE_T  prevsize;  /* its size */
2438
 
2439
  mchunkptr remainder;        /* holds split off extra space from newp */
2440
  INTERNAL_SIZE_T  remainder_size;   /* its size */
2441
 
2442
  mchunkptr bck;              /* misc temp for linking */
2443
  mchunkptr fwd;              /* misc temp for linking */
2444
 
2445
#ifdef REALLOC_ZERO_BYTES_FREES
2446
  if (bytes == 0) { fREe(oldmem); return 0; }
2447
#endif
2448
 
2449
 
2450
  /* realloc of null is supposed to be same as malloc */
2451
  if (oldmem == 0) return mALLOc(bytes);
2452
 
2453
  newp    = oldp    = mem2chunk(oldmem);
2454
  newsize = oldsize = chunksize(oldp);
2455
 
2456
 
2457
  nb = request2size(bytes);
2458
 
2459
#if HAVE_MMAP
2460
  if (chunk_is_mmapped(oldp))
2461
  {
2462
#if HAVE_MREMAP
2463
    newp = mremap_chunk(oldp, nb);
2464
    if(newp) return chunk2mem(newp);
2465
#endif
2466
    /* Note the extra SIZE_SZ overhead. */
2467
    if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
2468
    /* Must alloc, copy, free. */
2469
    newmem = mALLOc(bytes);
2470
    if (newmem == 0) return 0; /* propagate failure */
2471
    MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
2472
    munmap_chunk(oldp);
2473
    return newmem;
2474
  }
2475
#endif
2476
 
2477
  check_inuse_chunk(oldp);
2478
 
2479
  if ((long)(oldsize) < (long)(nb))
2480
  {
2481
 
2482
    /* Try expanding forward */
2483
 
2484
    next = chunk_at_offset(oldp, oldsize);
2485
    if (next == top || !inuse(next))
2486
    {
2487
      nextsize = chunksize(next);
2488
 
2489
      /* Forward into top only if a remainder */
2490
      if (next == top)
2491
      {
2492
        if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE))
2493
        {
2494
          newsize += nextsize;
2495
          top = chunk_at_offset(oldp, nb);
2496
          set_head(top, (newsize - nb) | PREV_INUSE);
2497
          set_head_size(oldp, nb);
2498
          return chunk2mem(oldp);
2499
        }
2500
      }
2501
 
2502
      /* Forward into next chunk */
2503
      else if (((long)(nextsize + newsize) >= (long)(nb)))
2504
      {
2505
        unlink(next, bck, fwd);
2506
        newsize  += nextsize;
2507
        goto split;
2508
      }
2509
    }
2510
    else
2511
    {
2512
      next = 0;
2513
      nextsize = 0;
2514
    }
2515
 
2516
    /* Try shifting backwards. */
2517
 
2518
    if (!prev_inuse(oldp))
2519
    {
2520
      prev = prev_chunk(oldp);
2521
      prevsize = chunksize(prev);
2522
 
2523
      /* try forward + backward first to save a later consolidation */
2524
 
2525
      if (next != 0)
2526
      {
2527
        /* into top */
2528
        if (next == top)
2529
        {
2530
          if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE))
2531
          {
2532
            unlink(prev, bck, fwd);
2533
            newp = prev;
2534
            newsize += prevsize + nextsize;
2535
            newmem = chunk2mem(newp);
2536
            MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2537
            top = chunk_at_offset(newp, nb);
2538
            set_head(top, (newsize - nb) | PREV_INUSE);
2539
            set_head_size(newp, nb);
2540
            return newmem;
2541
          }
2542
        }
2543
 
2544
        /* into next chunk */
2545
        else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
2546
        {
2547
          unlink(next, bck, fwd);
2548
          unlink(prev, bck, fwd);
2549
          newp = prev;
2550
          newsize += nextsize + prevsize;
2551
          newmem = chunk2mem(newp);
2552
          MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2553
          goto split;
2554
        }
2555
      }
2556
 
2557
      /* backward only */
2558
      if (prev != 0 && (long)(prevsize + newsize) >= (long)nb)
2559
      {
2560
        unlink(prev, bck, fwd);
2561
        newp = prev;
2562
        newsize += prevsize;
2563
        newmem = chunk2mem(newp);
2564
        MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2565
        goto split;
2566
      }
2567
    }
2568
 
2569
    /* Must allocate */
2570
 
2571
    newmem = mALLOc (bytes);
2572
 
2573
    if (newmem == 0)  /* propagate failure */
2574
      return 0;
2575
 
2576
    /* Avoid copy if newp is next chunk after oldp. */
2577
    /* (This can only happen when new chunk is sbrk'ed.) */
2578
 
2579
    if ( (newp = mem2chunk(newmem)) == next_chunk(oldp))
2580
    {
2581
      newsize += chunksize(newp);
2582
      newp = oldp;
2583
      goto split;
2584
    }
2585
 
2586
    /* Otherwise copy, free, and exit */
2587
    MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2588
    fREe(oldmem);
2589
    return newmem;
2590
  }
2591
 
2592
 
2593
 split:  /* split off extra room in old or expanded chunk */
2594
 
2595
  if (newsize - nb >= MINSIZE) /* split off remainder */
2596
  {
2597
    remainder = chunk_at_offset(newp, nb);
2598
    remainder_size = newsize - nb;
2599
    set_head_size(newp, nb);
2600
    set_head(remainder, remainder_size | PREV_INUSE);
2601
    set_inuse_bit_at_offset(remainder, remainder_size);
2602
    fREe(chunk2mem(remainder)); /* let free() deal with it */
2603
  }
2604
  else
2605
  {
2606
    set_head_size(newp, newsize);
2607
    set_inuse_bit_at_offset(newp, newsize);
2608
  }
2609
 
2610
  check_inuse_chunk(newp);
2611
  return chunk2mem(newp);
2612
}
2613
 
2614
 
2615
 
2616
 
2617
/*
2618
 
2619
  memalign algorithm:
2620
 
2621
    memalign requests more than enough space from malloc, finds a spot
2622
    within that chunk that meets the alignment request, and then
2623
    possibly frees the leading and trailing space.
2624
 
2625
    The alignment argument must be a power of two. This property is not
2626
    checked by memalign, so misuse may result in random runtime errors.
2627
 
2628
    8-byte alignment is guaranteed by normal malloc calls, so don't
2629
    bother calling memalign with an argument of 8 or less.
2630
 
2631
    Overreliance on memalign is a sure way to fragment space.
2632
 
2633
*/
2634
 
2635
 
2636
#if __STD_C
2637
Void_t* mEMALIGn(size_t alignment, size_t bytes)
2638
#else
2639
Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
2640
#endif
2641
{
2642
  INTERNAL_SIZE_T    nb;      /* padded  request size */
2643
  char*     m;                /* memory returned by malloc call */
2644
  mchunkptr p;                /* corresponding chunk */
2645
  char*     brk;              /* alignment point within p */
2646
  mchunkptr newp;             /* chunk to return */
2647
  INTERNAL_SIZE_T  newsize;   /* its size */
2648
  INTERNAL_SIZE_T  leadsize;  /* leading space befor alignment point */
2649
  mchunkptr remainder;        /* spare room at end to split off */
2650
  long      remainder_size;   /* its size */
2651
 
2652
  /* If need less alignment than we give anyway, just relay to malloc */
2653
 
2654
  if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);
2655
 
2656
  /* Otherwise, ensure that it is at least a minimum chunk size */
2657
 
2658
  if (alignment <  MINSIZE) alignment = MINSIZE;
2659
 
2660
  /* Call malloc with worst case padding to hit alignment. */
2661
 
2662
  nb = request2size(bytes);
2663
  m  = (char*)(mALLOc(nb + alignment + MINSIZE));
2664
 
2665
  if (m == 0) return 0; /* propagate failure */
2666
 
2667
  p = mem2chunk(m);
2668
 
2669
  if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
2670
  {
2671
#if HAVE_MMAP
2672
    if(chunk_is_mmapped(p))
2673
      return chunk2mem(p); /* nothing more to do */
2674
#endif
2675
  }
2676
  else /* misaligned */
2677
  {
2678
    /*
2679
      Find an aligned spot inside chunk.
2680
      Since we need to give back leading space in a chunk of at
2681
      least MINSIZE, if the first calculation places us at
2682
      a spot with less than MINSIZE leader, we can move to the
2683
      next aligned spot -- we've allocated enough total room so that
2684
      this is always possible.
2685
    */
2686
 
2687
    brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -alignment);
2688
    if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment;
2689
 
2690
    newp = (mchunkptr)brk;
2691
    leadsize = brk - (char*)(p);
2692
    newsize = chunksize(p) - leadsize;
2693
 
2694
#if HAVE_MMAP
2695
    if(chunk_is_mmapped(p))
2696
    {
2697
      newp->prev_size = p->prev_size + leadsize;
2698
      set_head(newp, newsize|IS_MMAPPED);
2699
      return chunk2mem(newp);
2700
    }
2701
#endif
2702
 
2703
    /* give back leader, use the rest */
2704
 
2705
    set_head(newp, newsize | PREV_INUSE);
2706
    set_inuse_bit_at_offset(newp, newsize);
2707
    set_head_size(p, leadsize);
2708
    fREe(chunk2mem(p));
2709
    p = newp;
2710
 
2711
    assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0);
2712
  }
2713
 
2714
  /* Also give back spare room at the end */
2715
 
2716
  remainder_size = chunksize(p) - nb;
2717
 
2718
  if (remainder_size >= (long)MINSIZE)
2719
  {
2720
    remainder = chunk_at_offset(p, nb);
2721
    set_head(remainder, remainder_size | PREV_INUSE);
2722
    set_head_size(p, nb);
2723
    fREe(chunk2mem(remainder));
2724
  }
2725
 
2726
  check_inuse_chunk(p);
2727
  return chunk2mem(p);
2728
 
2729
}
2730
 
2731
 
2732
 
2733
 
2734
/*
2735
    valloc just invokes memalign with alignment argument equal
2736
    to the page size of the system (or as near to this as can
2737
    be figured out from all the includes/defines above.)
2738
*/
2739
 
2740
#if __STD_C
2741
Void_t* vALLOc(size_t bytes)
2742
#else
2743
Void_t* vALLOc(bytes) size_t bytes;
2744
#endif
2745
{
2746
  return mEMALIGn (malloc_getpagesize, bytes);
2747
}
2748
 
2749
/*
2750
  pvalloc just invokes valloc for the nearest pagesize
2751
  that will accommodate request
2752
*/
2753
 
2754
 
2755
#if __STD_C
2756
Void_t* pvALLOc(size_t bytes)
2757
#else
2758
Void_t* pvALLOc(bytes) size_t bytes;
2759
#endif
2760
{
2761
  size_t pagesize = malloc_getpagesize;
2762
  return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
2763
}
2764
 
2765
/*
2766
 
2767
  calloc calls malloc, then zeroes out the allocated chunk.
2768
 
2769
*/
2770
 
2771
#if __STD_C
2772
Void_t* cALLOc(size_t n, size_t elem_size)
2773
#else
2774
Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
2775
#endif
2776
{
2777
  mchunkptr p;
2778
  INTERNAL_SIZE_T csz;
2779
 
2780
  INTERNAL_SIZE_T sz = n * elem_size;
2781
 
2782
  /* check if expand_top called, in which case don't need to clear */
2783
#if MORECORE_CLEARS
2784
  mchunkptr oldtop = top;
2785
  INTERNAL_SIZE_T oldtopsize = chunksize(top);
2786
#endif
2787
  Void_t* mem = mALLOc (sz);
2788
 
2789
  if (mem == 0)
2790
    return 0;
2791
  else
2792
  {
2793
    p = mem2chunk(mem);
2794
 
2795
    /* Two optional cases in which clearing not necessary */
2796
 
2797
 
2798
#if HAVE_MMAP
2799
    if (chunk_is_mmapped(p)) return mem;
2800
#endif
2801
 
2802
    csz = chunksize(p);
2803
 
2804
#if MORECORE_CLEARS
2805
    if (p == oldtop && csz > oldtopsize)
2806
    {
2807
      /* clear only the bytes from non-freshly-sbrked memory */
2808
      csz = oldtopsize;
2809
    }
2810
#endif
2811
 
2812
    MALLOC_ZERO(mem, csz - SIZE_SZ);
2813
    return mem;
2814
  }
2815
}
2816
 
2817
/*
2818
 
2819
  cfree just calls free. It is needed/defined on some systems
2820
  that pair it with calloc, presumably for odd historical reasons.
2821
 
2822
*/
2823
 
2824
#if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__)
2825
#if __STD_C
2826
void cfree(Void_t *mem)
2827
#else
2828
void cfree(mem) Void_t *mem;
2829
#endif
2830
{
2831
  free(mem);
2832
}
2833
#endif
2834
 
2835
 
2836
 
2837
/*
2838
 
2839
    Malloc_trim gives memory back to the system (via negative
2840
    arguments to sbrk) if there is unused memory at the `high' end of
2841
    the malloc pool. You can call this after freeing large blocks of
2842
    memory to potentially reduce the system-level memory requirements
2843
    of a program. However, it cannot guarantee to reduce memory. Under
2844
    some allocation patterns, some large free blocks of memory will be
2845
    locked between two used chunks, so they cannot be given back to
2846
    the system.
2847
 
2848
    The `pad' argument to malloc_trim represents the amount of free
2849
    trailing space to leave untrimmed. If this argument is zero,
2850
    only the minimum amount of memory to maintain internal data
2851
    structures will be left (one page or less). Non-zero arguments
2852
    can be supplied to maintain enough trailing space to service
2853
    future expected allocations without having to re-obtain memory
2854
    from the system.
2855
 
2856
    Malloc_trim returns 1 if it actually released any memory, else 0.
2857
 
2858
*/
2859
 
2860
#if __STD_C
2861
int malloc_trim(size_t pad)
2862
#else
2863
int malloc_trim(pad) size_t pad;
2864
#endif
2865
{
2866
  long  top_size;        /* Amount of top-most memory */
2867
  long  extra;           /* Amount to release */
2868
  char* current_brk;     /* address returned by pre-check sbrk call */
2869
  char* new_brk;         /* address returned by negative sbrk call */
2870
 
2871
  unsigned long pagesz = malloc_getpagesize;
2872
 
2873
  top_size = chunksize(top);
2874
  extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
2875
 
2876
  if (extra < (long)pagesz)  /* Not enough memory to release */
2877
    return 0;
2878
 
2879
  else
2880
  {
2881
    /* Test to make sure no one else called sbrk */
2882
    current_brk = (char*)(MORECORE (0));
2883
    if (current_brk != (char*)(top) + top_size)
2884
      return 0;     /* Apparently we don't own memory; must fail */
2885
 
2886
    else
2887
    {
2888
      new_brk = (char*)(MORECORE (-extra));
2889
 
2890
      if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */
2891
      {
2892
        /* Try to figure out what we have */
2893
        current_brk = (char*)(MORECORE (0));
2894
        top_size = current_brk - (char*)top;
2895
        if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
2896
        {
2897
          sbrked_mem = current_brk - sbrk_base;
2898
          set_head(top, top_size | PREV_INUSE);
2899
        }
2900
        check_chunk(top);
2901
        return 0;
2902
      }
2903
 
2904
      else
2905
      {
2906
        /* Success. Adjust top accordingly. */
2907
        set_head(top, (top_size - extra) | PREV_INUSE);
2908
        sbrked_mem -= extra;
2909
        check_chunk(top);
2910
        return 1;
2911
      }
2912
    }
2913
  }
2914
}
2915
 
2916
 
2917
 
2918
/*
2919
  malloc_usable_size:
2920
 
2921
    This routine tells you how many bytes you can actually use in an
2922
    allocated chunk, which may be more than you requested (although
2923
    often not). You can use this many bytes without worrying about
2924
    overwriting other allocated objects. Not a particularly great
2925
    programming practice, but still sometimes useful.
2926
 
2927
*/
2928
 
2929
#if __STD_C
2930
size_t malloc_usable_size(Void_t* mem)
2931
#else
2932
size_t malloc_usable_size(mem) Void_t* mem;
2933
#endif
2934
{
2935
  mchunkptr p;
2936
  if (mem == 0)
2937
    return 0;
2938
  else
2939
  {
2940
    p = mem2chunk(mem);
2941
    if(!chunk_is_mmapped(p))
2942
    {
2943
      if (!inuse(p)) return 0;
2944
      check_inuse_chunk(p);
2945
      return chunksize(p) - SIZE_SZ;
2946
    }
2947
    return chunksize(p) - 2*SIZE_SZ;
2948
  }
2949
}
2950
 
2951
 
2952
 
2953
 
2954
/* Utility to update current_mallinfo for malloc_stats and mallinfo() */
2955
 
2956
static void malloc_update_mallinfo()
2957
{
2958
  int i;
2959
  mbinptr b;
2960
  mchunkptr p;
2961
#if DEBUG
2962
  mchunkptr q;
2963
#endif
2964
 
2965
  INTERNAL_SIZE_T avail = chunksize(top);
2966
  int   navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;
2967
 
2968
  for (i = 1; i < NAV; ++i)
2969
  {
2970
    b = bin_at(i);
2971
    for (p = last(b); p != b; p = p->bk)
2972
    {
2973
#if DEBUG
2974
      check_free_chunk(p);
2975
      for (q = next_chunk(p);
2976
           q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
2977
           q = next_chunk(q))
2978
        check_inuse_chunk(q);
2979
#endif
2980
      avail += chunksize(p);
2981
      navail++;
2982
    }
2983
  }
2984
 
2985
  current_mallinfo.ordblks = navail;
2986
  current_mallinfo.uordblks = sbrked_mem - avail;
2987
  current_mallinfo.fordblks = avail;
2988
  current_mallinfo.hblks = n_mmaps;
2989
  current_mallinfo.hblkhd = mmapped_mem;
2990
  current_mallinfo.keepcost = chunksize(top);
2991
 
2992
}
2993
 
2994
 
2995
 
2996
/*
2997
 
2998
  malloc_stats:
2999
 
3000
    Prints on stderr the amount of space obtain from the system (both
3001
    via sbrk and mmap), the maximum amount (which may be more than
3002
    current if malloc_trim and/or munmap got called), the maximum
3003
    number of simultaneous mmap regions used, and the current number
3004
    of bytes allocated via malloc (or realloc, etc) but not yet
3005
    freed. (Note that this is the number of bytes allocated, not the
3006
    number requested. It will be larger than the number requested
3007
    because of alignment and bookkeeping overhead.)
3008
 
3009
*/
3010
 
3011
void malloc_stats()
3012
{
3013
  malloc_update_mallinfo();
3014
  fprintf(stderr, "max system bytes = %10u\n",
3015
          (unsigned int)(max_total_mem));
3016
  fprintf(stderr, "system bytes     = %10u\n",
3017
          (unsigned int)(sbrked_mem + mmapped_mem));
3018
  fprintf(stderr, "in use bytes     = %10u\n",
3019
          (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
3020
#if HAVE_MMAP
3021
  fprintf(stderr, "max mmap regions = %10u\n",
3022
          (unsigned int)max_n_mmaps);
3023
#endif
3024
}
3025
 
3026
/*
3027
  mallinfo returns a copy of updated current mallinfo.
3028
*/
3029
 
3030
struct mallinfo mALLINFo()
3031
{
3032
  malloc_update_mallinfo();
3033
  return current_mallinfo;
3034
}
3035
 
3036
 
3037
 
3038
 
3039
/*
3040
  mallopt:
3041
 
3042
    mallopt is the general SVID/XPG interface to tunable parameters.
3043
    The format is to provide a (parameter-number, parameter-value) pair.
3044
    mallopt then sets the corresponding parameter to the argument
3045
    value if it can (i.e., so long as the value is meaningful),
3046
    and returns 1 if successful else 0.
3047
 
3048
    See descriptions of tunable parameters above.
3049
 
3050
*/
3051
 
3052
#if __STD_C
3053
int mALLOPt(int param_number, int value)
3054
#else
3055
int mALLOPt(param_number, value) int param_number; int value;
3056
#endif
3057
{
3058
  switch(param_number)
3059
  {
3060
    case M_TRIM_THRESHOLD:
3061
      trim_threshold = value; return 1;
3062
    case M_TOP_PAD:
3063
      top_pad = value; return 1;
3064
    case M_MMAP_THRESHOLD:
3065
      mmap_threshold = value; return 1;
3066
    case M_MMAP_MAX:
3067
#if HAVE_MMAP
3068
      n_mmaps_max = value; return 1;
3069
#else
3070
      if (value != 0) return 0; else  n_mmaps_max = value; return 1;
3071
#endif
3072
 
3073
    default:
3074
      return 0;
3075
  }
3076
}
3077
 
3078
/*
3079
 
3080
History:
3081
 
3082
    V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
3083
      * Added pvalloc, as recommended by H.J. Liu
3084
      * Added 64bit pointer support mainly from Wolfram Gloger
3085
      * Added anonymously donated WIN32 sbrk emulation
3086
      * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
3087
      * malloc_extend_top: fix mask error that caused wastage after
3088
        foreign sbrks
3089
      * Add linux mremap support code from HJ Liu
3090
 
3091
    V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
3092
      * Integrated most documentation with the code.
3093
      * Add support for mmap, with help from
3094
        Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
3095
      * Use last_remainder in more cases.
3096
      * Pack bins using idea from  colin@nyx10.cs.du.edu
3097
      * Use ordered bins instead of best-fit threshhold
3098
      * Eliminate block-local decls to simplify tracing and debugging.
3099
      * Support another case of realloc via move into top
3100
      * Fix error occuring when initial sbrk_base not word-aligned.
3101
      * Rely on page size for units instead of SBRK_UNIT to
3102
        avoid surprises about sbrk alignment conventions.
3103
      * Add mallinfo, mallopt. Thanks to Raymond Nijssen
3104
        (raymond@es.ele.tue.nl) for the suggestion.
3105
      * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
3106
      * More precautions for cases where other routines call sbrk,
3107
        courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
3108
      * Added macros etc., allowing use in linux libc from
3109
        H.J. Lu (hjl@gnu.ai.mit.edu)
3110
      * Inverted this history list
3111
 
3112
    V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
3113
      * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
3114
      * Removed all preallocation code since under current scheme
3115
        the work required to undo bad preallocations exceeds
3116
        the work saved in good cases for most test programs.
3117
      * No longer use return list or unconsolidated bins since
3118
        no scheme using them consistently outperforms those that don't
3119
        given above changes.
3120
      * Use best fit for very large chunks to prevent some worst-cases.
3121
      * Added some support for debugging
3122
 
3123
    V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
3124
      * Removed footers when chunks are in use. Thanks to
3125
        Paul Wilson (wilson@cs.texas.edu) for the suggestion.
3126
 
3127
    V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
3128
      * Added malloc_trim, with help from Wolfram Gloger
3129
        (wmglo@Dent.MED.Uni-Muenchen.DE).
3130
 
3131
    V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)
3132
 
3133
    V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
3134
      * realloc: try to expand in both directions
3135
      * malloc: swap order of clean-bin strategy;
3136
      * realloc: only conditionally expand backwards
3137
      * Try not to scavenge used bins
3138
      * Use bin counts as a guide to preallocation
3139
      * Occasionally bin return list chunks in first scan
3140
      * Add a few optimizations from colin@nyx10.cs.du.edu
3141
 
3142
    V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
3143
      * faster bin computation & slightly different binning
3144
      * merged all consolidations to one part of malloc proper
3145
         (eliminating old malloc_find_space & malloc_clean_bin)
3146
      * Scan 2 returns chunks (not just 1)
3147
      * Propagate failure in realloc if malloc returns 0
3148
      * Add stuff to allow compilation on non-ANSI compilers
3149
          from kpv@research.att.com
3150
 
3151
    V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
3152
      * removed potential for odd address access in prev_chunk
3153
      * removed dependency on getpagesize.h
3154
      * misc cosmetics and a bit more internal documentation
3155
      * anticosmetics: mangled names in macros to evade debugger strangeness
3156
      * tested on sparc, hp-700, dec-mips, rs6000
3157
          with gcc & native cc (hp, dec only) allowing
3158
          Detlefs & Zorn comparison study (in SIGPLAN Notices.)
3159
 
3160
    Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
3161
      * Based loosely on libg++-1.2X malloc. (It retains some of the overall
3162
         structure of old version,  but most details differ.)
3163
 
3164
*/
3165
 
3166
 

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