Blame view

include/malloc.h 32.9 KB
5b1d71372   wdenk   Initial revision
1
2
3
4
5
6
7
8
  /*
    A version of malloc/free/realloc written by Doug Lea and released to the
    public domain.  Send questions/comments/complaints/performance data
    to dl@cs.oswego.edu
  
  * VERSION 2.6.6  Sun Mar  5 19:10:03 2000  Doug Lea  (dl at gee)
  
     Note: There may be an updated version of this malloc obtainable at
8bde7f776   wdenk   * Code cleanup:
9
10
  	   ftp://g.oswego.edu/pub/misc/malloc.c
  	 Check before installing!
5b1d71372   wdenk   Initial revision
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
  
  * Why use this malloc?
  
    This is not the fastest, most space-conserving, most portable, or
    most tunable malloc ever written. However it is among the fastest
    while also being among the most space-conserving, portable and tunable.
    Consistent balance across these factors results in a good general-purpose
    allocator. For a high-level description, see
       http://g.oswego.edu/dl/html/malloc.html
  
  * Synopsis of public routines
  
    (Much fuller descriptions are contained in the program documentation below.)
  
    malloc(size_t n);
       Return a pointer to a newly allocated chunk of at least n bytes, or null
       if no space is available.
    free(Void_t* p);
       Release the chunk of memory pointed to by p, or no effect if p is null.
    realloc(Void_t* p, size_t n);
       Return a pointer to a chunk of size n that contains the same data
       as does chunk p up to the minimum of (n, p's size) bytes, or null
       if no space is available. The returned pointer may or may not be
       the same as p. If p is null, equivalent to malloc.  Unless the
       #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
       size argument of zero (re)allocates a minimum-sized chunk.
    memalign(size_t alignment, size_t n);
       Return a pointer to a newly allocated chunk of n bytes, aligned
       in accord with the alignment argument, which must be a power of
       two.
    valloc(size_t n);
       Equivalent to memalign(pagesize, n), where pagesize is the page
       size of the system (or as near to this as can be figured out from
       all the includes/defines below.)
    pvalloc(size_t n);
       Equivalent to valloc(minimum-page-that-holds(n)), that is,
       round up n to nearest pagesize.
    calloc(size_t unit, size_t quantity);
       Returns a pointer to quantity * unit bytes, with all locations
       set to zero.
    cfree(Void_t* p);
       Equivalent to free(p).
    malloc_trim(size_t pad);
       Release all but pad bytes of freed top-most memory back
       to the system. Return 1 if successful, else 0.
    malloc_usable_size(Void_t* p);
       Report the number usable allocated bytes associated with allocated
       chunk p. This may or may not report more bytes than were requested,
       due to alignment and minimum size constraints.
    malloc_stats();
       Prints brief summary statistics on stderr.
    mallinfo()
       Returns (by copy) a struct containing various summary statistics.
    mallopt(int parameter_number, int parameter_value)
       Changes one of the tunable parameters described below. Returns
       1 if successful in changing the parameter, else 0.
  
  * Vital statistics:
  
    Alignment:                            8-byte
         8 byte alignment is currently hardwired into the design.  This
         seems to suffice for all current machines and C compilers.
  
    Assumed pointer representation:       4 or 8 bytes
         Code for 8-byte pointers is untested by me but has worked
         reliably by Wolfram Gloger, who contributed most of the
         changes supporting this.
  
    Assumed size_t  representation:       4 or 8 bytes
         Note that size_t is allowed to be 4 bytes even if pointers are 8.
  
    Minimum overhead per allocated chunk: 4 or 8 bytes
         Each malloced chunk has a hidden overhead of 4 bytes holding size
         and status information.
  
    Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
8bde7f776   wdenk   * Code cleanup:
87
  			  8-byte ptrs:  24/32 bytes (including, 4/8 overhead)
5b1d71372   wdenk   Initial revision
88
89
90
91
92
93
94
95
96
97
98
  
         When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
         ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
         needed; 4 (8) for a trailing size field
         and 8 (16) bytes for free list pointers. Thus, the minimum
         allocatable size is 16/24/32 bytes.
  
         Even a request for zero bytes (i.e., malloc(0)) returns a
         pointer to something of the minimum allocatable size.
  
    Maximum allocated size: 4-byte size_t: 2^31 -  8 bytes
8bde7f776   wdenk   * Code cleanup:
99
  			  8-byte size_t: 2^63 - 16 bytes
5b1d71372   wdenk   Initial revision
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
  
         It is assumed that (possibly signed) size_t bit values suffice to
         represent chunk sizes. `Possibly signed' is due to the fact
         that `size_t' may be defined on a system as either a signed or
         an unsigned type. To be conservative, values that would appear
         as negative numbers are avoided.
         Requests for sizes with a negative sign bit when the request
         size is treaded as a long will return null.
  
    Maximum overhead wastage per allocated chunk: normally 15 bytes
  
         Alignnment demands, plus the minimum allocatable size restriction
         make the normal worst-case wastage 15 bytes (i.e., up to 15
         more bytes will be allocated than were requested in malloc), with
         two exceptions:
8bde7f776   wdenk   * Code cleanup:
115
116
117
118
119
  	 1. Because requests for zero bytes allocate non-zero space,
  	    the worst case wastage for a request of zero bytes is 24 bytes.
  	 2. For requests >= mmap_threshold that are serviced via
  	    mmap(), the worst case wastage is 8 bytes plus the remainder
  	    from a system page (the minimal mmap unit); typically 4096 bytes.
5b1d71372   wdenk   Initial revision
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
  
  * Limitations
  
      Here are some features that are NOT currently supported
  
      * No user-definable hooks for callbacks and the like.
      * No automated mechanism for fully checking that all accesses
        to malloced memory stay within their bounds.
      * No support for compaction.
  
  * Synopsis of compile-time options:
  
      People have reported using previous versions of this malloc on all
      versions of Unix, sometimes by tweaking some of the defines
      below. It has been tested most extensively on Solaris and
      Linux. It is also reported to work on WIN32 platforms.
      People have also reported adapting this malloc for use in
      stand-alone embedded systems.
  
      The implementation is in straight, hand-tuned ANSI C.  Among other
      consequences, it uses a lot of macros.  Because of this, to be at
      all usable, this code should be compiled using an optimizing compiler
      (for example gcc -O2) that can simplify expressions and control
      paths.
  
    __STD_C                  (default: derived from C compiler defines)
       Nonzero if using ANSI-standard C compiler, a C++ compiler, or
       a C compiler sufficiently close to ANSI to get away with it.
    DEBUG                    (default: NOT defined)
       Define to enable debugging. Adds fairly extensive assertion-based
       checking to help track down memory errors, but noticeably slows down
       execution.
    REALLOC_ZERO_BYTES_FREES (default: NOT defined)
       Define this if you think that realloc(p, 0) should be equivalent
       to free(p). Otherwise, since malloc returns a unique pointer for
       malloc(0), so does realloc(p, 0).
    HAVE_MEMCPY               (default: defined)
       Define if you are not otherwise using ANSI STD C, but still
       have memcpy and memset in your C library and want to use them.
       Otherwise, simple internal versions are supplied.
    USE_MEMCPY               (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
       Define as 1 if you want the C library versions of memset and
       memcpy called in realloc and calloc (otherwise macro versions are used).
       At least on some platforms, the simple macro versions usually
       outperform libc versions.
    HAVE_MMAP                 (default: defined as 1)
       Define to non-zero to optionally make malloc() use mmap() to
       allocate very large blocks.
    HAVE_MREMAP                 (default: defined as 0 unless Linux libc set)
       Define to non-zero to optionally make realloc() use mremap() to
       reallocate very large blocks.
    malloc_getpagesize        (default: derived from system #includes)
       Either a constant or routine call returning the system page size.
    HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
       Optionally define if you are on a system with a /usr/include/malloc.h
       that declares struct mallinfo. It is not at all necessary to
       define this even if you do, but will ensure consistency.
    INTERNAL_SIZE_T           (default: size_t)
       Define to a 32-bit type (probably `unsigned int') if you are on a
       64-bit machine, yet do not want or need to allow malloc requests of
       greater than 2^31 to be handled. This saves space, especially for
       very small chunks.
    INTERNAL_LINUX_C_LIB      (default: NOT defined)
       Defined only when compiled as part of Linux libc.
       Also note that there is some odd internal name-mangling via defines
       (for example, internally, `malloc' is named `mALLOc') needed
       when compiling in this case. These look funny but don't otherwise
       affect anything.
    WIN32                     (default: undefined)
       Define this on MS win (95, nt) platforms to compile in sbrk emulation.
    LACKS_UNISTD_H            (default: undefined if not WIN32)
       Define this if your system does not have a <unistd.h>.
    LACKS_SYS_PARAM_H         (default: undefined if not WIN32)
       Define this if your system does not have a <sys/param.h>.
    MORECORE                  (default: sbrk)
       The name of the routine to call to obtain more memory from the system.
    MORECORE_FAILURE          (default: -1)
       The value returned upon failure of MORECORE.
    MORECORE_CLEARS           (default 1)
       True (1) if the routine mapped to MORECORE zeroes out memory (which
       holds for sbrk).
    DEFAULT_TRIM_THRESHOLD
    DEFAULT_TOP_PAD
    DEFAULT_MMAP_THRESHOLD
    DEFAULT_MMAP_MAX
       Default values of tunable parameters (described in detail below)
       controlling interaction with host system routines (sbrk, mmap, etc).
       These values may also be changed dynamically via mallopt(). The
       preset defaults are those that give best performance for typical
       programs/systems.
    USE_DL_PREFIX             (default: undefined)
       Prefix all public routines with the string 'dl'.  Useful to
       quickly avoid procedure declaration conflicts and linker symbol
       conflicts with existing memory allocation routines.
  
  
  */
  
  
  
  
  /* Preliminaries */
  
  #ifndef __STD_C
  #ifdef __STDC__
  #define __STD_C     1
  #else
  #if __cplusplus
  #define __STD_C     1
  #else
  #define __STD_C     0
  #endif /*__cplusplus*/
  #endif /*__STDC__*/
  #endif /*__STD_C*/
  
  #ifndef Void_t
  #if (__STD_C || defined(WIN32))
  #define Void_t      void
  #else
  #define Void_t      char
  #endif
  #endif /*Void_t*/
  
  #if __STD_C
  #include <linux/stddef.h>	/* for size_t */
  #else
  #include <sys/types.h>
  #endif	/* __STD_C */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #if 0	/* not for U-Boot */
  #include <stdio.h>	/* needed for malloc_stats */
  #endif
  
  
  /*
    Compile-time options
  */
  
  
  /*
      Debugging:
  
      Because freed chunks may be overwritten with link fields, this
      malloc will often die when freed memory is overwritten by user
      programs.  This can be very effective (albeit in an annoying way)
      in helping track down dangling pointers.
  
      If you compile with -DDEBUG, a number of assertion checks are
      enabled that will catch more memory errors. You probably won't be
      able to make much sense of the actual assertion errors, but they
      should help you locate incorrectly overwritten memory.  The
      checking is fairly extensive, and will slow down execution
      noticeably. Calling malloc_stats or mallinfo with DEBUG set will
      attempt to check every non-mmapped allocated and free chunk in the
      course of computing the summmaries. (By nature, mmapped regions
      cannot be checked very much automatically.)
  
      Setting DEBUG may also be helpful if you are trying to modify
      this code. The assertions in the check routines spell out in more
      detail the assumptions and invariants underlying the algorithms.
  
  */
  
  #ifdef DEBUG
  /* #include <assert.h> */
  #define assert(x) ((void)0)
  #else
  #define assert(x) ((void)0)
  #endif
  
  
  /*
    INTERNAL_SIZE_T is the word-size used for internal bookkeeping
    of chunk sizes. On a 64-bit machine, you can reduce malloc
    overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
    at the expense of not being able to handle requests greater than
    2^31. This limitation is hardly ever a concern; you are encouraged
    to set this. However, the default version is the same as size_t.
  */
  
  #ifndef INTERNAL_SIZE_T
  #define INTERNAL_SIZE_T size_t
  #endif
  
  /*
    REALLOC_ZERO_BYTES_FREES should be set if a call to
    realloc with zero bytes should be the same as a call to free.
    Some people think it should. Otherwise, since this malloc
    returns a unique pointer for malloc(0), so does realloc(p, 0).
  */
  
  
  /*   #define REALLOC_ZERO_BYTES_FREES */
  
  
  /*
    WIN32 causes an emulation of sbrk to be compiled in
    mmap-based options are not currently supported in WIN32.
  */
  
  /* #define WIN32 */
  #ifdef WIN32
  #define MORECORE wsbrk
  #define HAVE_MMAP 0
  
  #define LACKS_UNISTD_H
  #define LACKS_SYS_PARAM_H
  
  /*
    Include 'windows.h' to get the necessary declarations for the
    Microsoft Visual C++ data structures and routines used in the 'sbrk'
    emulation.
  
    Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft
    Visual C++ header files are included.
  */
  #define WIN32_LEAN_AND_MEAN
  #include <windows.h>
  #endif
  
  
  /*
    HAVE_MEMCPY should be defined if you are not otherwise using
    ANSI STD C, but still have memcpy and memset in your C library
    and want to use them in calloc and realloc. Otherwise simple
    macro versions are defined here.
  
    USE_MEMCPY should be defined as 1 if you actually want to
    have memset and memcpy called. People report that the macro
    versions are often enough faster than libc versions on many
    systems that it is better to use them.
  
  */
  
  #define HAVE_MEMCPY
  
  #ifndef USE_MEMCPY
  #ifdef HAVE_MEMCPY
  #define USE_MEMCPY 1
  #else
  #define USE_MEMCPY 0
  #endif
  #endif
  
  #if (__STD_C || defined(HAVE_MEMCPY))
  
  #if __STD_C
  void* memset(void*, int, size_t);
  void* memcpy(void*, const void*, size_t);
  #else
  #ifdef WIN32
8bde7f776   wdenk   * Code cleanup:
375
376
  /* On Win32 platforms, 'memset()' and 'memcpy()' are already declared in */
  /* 'windows.h' */
5b1d71372   wdenk   Initial revision
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
  #else
  Void_t* memset();
  Void_t* memcpy();
  #endif
  #endif
  #endif
  
  #if USE_MEMCPY
  
  /* The following macros are only invoked with (2n+1)-multiples of
     INTERNAL_SIZE_T units, with a positive integer n. This is exploited
     for fast inline execution when n is small. */
  
  #define MALLOC_ZERO(charp, nbytes)                                            \
  do {                                                                          \
    INTERNAL_SIZE_T mzsz = (nbytes);                                            \
    if(mzsz <= 9*sizeof(mzsz)) {                                                \
      INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
      if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
8bde7f776   wdenk   * Code cleanup:
396
  				     *mz++ = 0;                               \
5b1d71372   wdenk   Initial revision
397
        if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
8bde7f776   wdenk   * Code cleanup:
398
399
400
401
402
403
  				     *mz++ = 0;                               \
  	if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
  				     *mz++ = 0; }}}                           \
  				     *mz++ = 0;                               \
  				     *mz++ = 0;                               \
  				     *mz   = 0;                               \
5b1d71372   wdenk   Initial revision
404
405
406
407
408
409
410
411
412
413
    } else memset((charp), 0, mzsz);                                            \
  } while(0)
  
  #define MALLOC_COPY(dest,src,nbytes)                                          \
  do {                                                                          \
    INTERNAL_SIZE_T mcsz = (nbytes);                                            \
    if(mcsz <= 9*sizeof(mcsz)) {                                                \
      INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
      INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
      if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
8bde7f776   wdenk   * Code cleanup:
414
  				     *mcdst++ = *mcsrc++;                     \
5b1d71372   wdenk   Initial revision
415
        if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
8bde7f776   wdenk   * Code cleanup:
416
417
418
419
420
421
  				     *mcdst++ = *mcsrc++;                     \
  	if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
  				     *mcdst++ = *mcsrc++; }}}                 \
  				     *mcdst++ = *mcsrc++;                     \
  				     *mcdst++ = *mcsrc++;                     \
  				     *mcdst   = *mcsrc  ;                     \
5b1d71372   wdenk   Initial revision
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
    } else memcpy(dest, src, mcsz);                                             \
  } while(0)
  
  #else /* !USE_MEMCPY */
  
  /* Use Duff's device for good zeroing/copying performance. */
  
  #define MALLOC_ZERO(charp, nbytes)                                            \
  do {                                                                          \
    INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
    long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
    if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
    switch (mctmp) {                                                            \
      case 0: for(;;) { *mzp++ = 0;                                             \
      case 7:           *mzp++ = 0;                                             \
      case 6:           *mzp++ = 0;                                             \
      case 5:           *mzp++ = 0;                                             \
      case 4:           *mzp++ = 0;                                             \
      case 3:           *mzp++ = 0;                                             \
      case 2:           *mzp++ = 0;                                             \
      case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
    }                                                                           \
  } while(0)
  
  #define MALLOC_COPY(dest,src,nbytes)                                          \
  do {                                                                          \
    INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
    INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
    long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
    if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
    switch (mctmp) {                                                            \
      case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
      case 7:           *mcdst++ = *mcsrc++;                                    \
      case 6:           *mcdst++ = *mcsrc++;                                    \
      case 5:           *mcdst++ = *mcsrc++;                                    \
      case 4:           *mcdst++ = *mcsrc++;                                    \
      case 3:           *mcdst++ = *mcsrc++;                                    \
      case 2:           *mcdst++ = *mcsrc++;                                    \
      case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
    }                                                                           \
  } while(0)
  
  #endif
  
  
  /*
    Define HAVE_MMAP to optionally make malloc() use mmap() to
    allocate very large blocks.  These will be returned to the
    operating system immediately after a free().
  */
  
  /***
  #ifndef HAVE_MMAP
  #define HAVE_MMAP 1
  #endif
  ***/
  #undef	HAVE_MMAP	/* Not available for U-Boot */
  
  /*
    Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
    large blocks.  This is currently only possible on Linux with
    kernel versions newer than 1.3.77.
  */
  
  /***
  #ifndef HAVE_MREMAP
  #ifdef INTERNAL_LINUX_C_LIB
  #define HAVE_MREMAP 1
  #else
  #define HAVE_MREMAP 0
  #endif
  #endif
  ***/
  #undef	HAVE_MREMAP	/* Not available for U-Boot */
  
  #if HAVE_MMAP
  
  #include <unistd.h>
  #include <fcntl.h>
  #include <sys/mman.h>
  
  #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
  #define MAP_ANONYMOUS MAP_ANON
  #endif
  
  #endif /* HAVE_MMAP */
  
  /*
    Access to system page size. To the extent possible, this malloc
    manages memory from the system in page-size units.
  
    The following mechanics for getpagesize were adapted from
    bsd/gnu getpagesize.h
  */
  
  #define	LACKS_UNISTD_H	/* Shortcut for U-Boot */
  #define	malloc_getpagesize	4096
  
  #ifndef LACKS_UNISTD_H
  #  include <unistd.h>
  #endif
  
  #ifndef malloc_getpagesize
  #  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
  #    ifndef _SC_PAGE_SIZE
  #      define _SC_PAGE_SIZE _SC_PAGESIZE
  #    endif
  #  endif
  #  ifdef _SC_PAGE_SIZE
  #    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
  #  else
  #    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
         extern size_t getpagesize();
  #      define malloc_getpagesize getpagesize()
  #    else
  #      ifdef WIN32
  #        define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */
  #      else
  #        ifndef LACKS_SYS_PARAM_H
  #          include <sys/param.h>
  #        endif
  #        ifdef EXEC_PAGESIZE
  #          define malloc_getpagesize EXEC_PAGESIZE
  #        else
  #          ifdef NBPG
  #            ifndef CLSIZE
  #              define malloc_getpagesize NBPG
  #            else
  #              define malloc_getpagesize (NBPG * CLSIZE)
  #            endif
  #          else
  #            ifdef NBPC
  #              define malloc_getpagesize NBPC
  #            else
  #              ifdef PAGESIZE
  #                define malloc_getpagesize PAGESIZE
  #              else
  #                define malloc_getpagesize (4096) /* just guess */
  #              endif
  #            endif
  #          endif
  #        endif
  #      endif
  #    endif
  #  endif
  #endif
5b1d71372   wdenk   Initial revision
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
  /*
  
    This version of malloc supports the standard SVID/XPG mallinfo
    routine that returns a struct containing the same kind of
    information you can get from malloc_stats. It should work on
    any SVID/XPG compliant system that has a /usr/include/malloc.h
    defining struct mallinfo. (If you'd like to install such a thing
    yourself, cut out the preliminary declarations as described above
    and below and save them in a malloc.h file. But there's no
    compelling reason to bother to do this.)
  
    The main declaration needed is the mallinfo struct that is returned
    (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
    bunch of fields, most of which are not even meaningful in this
    version of malloc. Some of these fields are are instead filled by
    mallinfo() with other numbers that might possibly be of interest.
  
    HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
    /usr/include/malloc.h file that includes a declaration of struct
    mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
    version is declared below.  These must be precisely the same for
    mallinfo() to work.
  
  */
  
  /* #define HAVE_USR_INCLUDE_MALLOC_H */
  
  #if HAVE_USR_INCLUDE_MALLOC_H
  #include "/usr/include/malloc.h"
  #else
  
  /* SVID2/XPG mallinfo structure */
  
  struct mallinfo {
    int arena;    /* total space allocated from system */
    int ordblks;  /* number of non-inuse chunks */
    int smblks;   /* unused -- always zero */
    int hblks;    /* number of mmapped regions */
    int hblkhd;   /* total space in mmapped regions */
    int usmblks;  /* unused -- always zero */
    int fsmblks;  /* unused -- always zero */
    int uordblks; /* total allocated space */
    int fordblks; /* total non-inuse space */
    int keepcost; /* top-most, releasable (via malloc_trim) space */
  };
  
  /* SVID2/XPG mallopt options */
  
  #define M_MXFAST  1    /* UNUSED in this malloc */
  #define M_NLBLKS  2    /* UNUSED in this malloc */
  #define M_GRAIN   3    /* UNUSED in this malloc */
  #define M_KEEP    4    /* UNUSED in this malloc */
  
  #endif
  
  /* mallopt options that actually do something */
  
  #define M_TRIM_THRESHOLD    -1
  #define M_TOP_PAD           -2
  #define M_MMAP_THRESHOLD    -3
  #define M_MMAP_MAX          -4
5b1d71372   wdenk   Initial revision
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
  #ifndef DEFAULT_TRIM_THRESHOLD
  #define DEFAULT_TRIM_THRESHOLD (128 * 1024)
  #endif
  
  /*
      M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
        to keep before releasing via malloc_trim in free().
  
        Automatic trimming is mainly useful in long-lived programs.
        Because trimming via sbrk can be slow on some systems, and can
        sometimes be wasteful (in cases where programs immediately
        afterward allocate more large chunks) the value should be high
        enough so that your overall system performance would improve by
        releasing.
  
        The trim threshold and the mmap control parameters (see below)
        can be traded off with one another. Trimming and mmapping are
        two different ways of releasing unused memory back to the
        system. Between these two, it is often possible to keep
        system-level demands of a long-lived program down to a bare
        minimum. For example, in one test suite of sessions measuring
        the XF86 X server on Linux, using a trim threshold of 128K and a
        mmap threshold of 192K led to near-minimal long term resource
        consumption.
  
        If you are using this malloc in a long-lived program, it should
        pay to experiment with these values.  As a rough guide, you
        might set to a value close to the average size of a process
        (program) running on your system.  Releasing this much memory
        would allow such a process to run in memory.  Generally, it's
        worth it to tune for trimming rather tham memory mapping when a
        program undergoes phases where several large chunks are
        allocated and released in ways that can reuse each other's
        storage, perhaps mixed with phases where there are no such
        chunks at all.  And in well-behaved long-lived programs,
        controlling release of large blocks via trimming versus mapping
        is usually faster.
  
        However, in most programs, these parameters serve mainly as
        protection against the system-level effects of carrying around
        massive amounts of unneeded memory. Since frequent calls to
        sbrk, mmap, and munmap otherwise degrade performance, the default
        parameters are set to relatively high values that serve only as
        safeguards.
  
        The default trim value is high enough to cause trimming only in
        fairly extreme (by current memory consumption standards) cases.
        It must be greater than page size to have any useful effect.  To
        disable trimming completely, you can set to (unsigned long)(-1);
  
  
  */
  
  
  #ifndef DEFAULT_TOP_PAD
  #define DEFAULT_TOP_PAD        (0)
  #endif
  
  /*
      M_TOP_PAD is the amount of extra `padding' space to allocate or
        retain whenever sbrk is called. It is used in two ways internally:
  
        * When sbrk is called to extend the top of the arena to satisfy
8bde7f776   wdenk   * Code cleanup:
692
693
  	a new malloc request, this much padding is added to the sbrk
  	request.
5b1d71372   wdenk   Initial revision
694
695
  
        * When malloc_trim is called automatically from free(),
8bde7f776   wdenk   * Code cleanup:
696
  	it is used as the `pad' argument.
5b1d71372   wdenk   Initial revision
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
  
        In both cases, the actual amount of padding is rounded
        so that the end of the arena is always a system page boundary.
  
        The main reason for using padding is to avoid calling sbrk so
        often. Having even a small pad greatly reduces the likelihood
        that nearly every malloc request during program start-up (or
        after trimming) will invoke sbrk, which needlessly wastes
        time.
  
        Automatic rounding-up to page-size units is normally sufficient
        to avoid measurable overhead, so the default is 0.  However, in
        systems where sbrk is relatively slow, it can pay to increase
        this value, at the expense of carrying around more memory than
        the program needs.
  
  */
  
  
  #ifndef DEFAULT_MMAP_THRESHOLD
  #define DEFAULT_MMAP_THRESHOLD (128 * 1024)
  #endif
  
  /*
  
      M_MMAP_THRESHOLD is the request size threshold for using mmap()
        to service a request. Requests of at least this size that cannot
        be allocated using already-existing space will be serviced via mmap.
        (If enough normal freed space already exists it is used instead.)
  
        Using mmap segregates relatively large chunks of memory so that
        they can be individually obtained and released from the host
        system. A request serviced through mmap is never reused by any
        other request (at least not directly; the system may just so
        happen to remap successive requests to the same locations).
  
        Segregating space in this way has the benefit that mmapped space
        can ALWAYS be individually released back to the system, which
        helps keep the system level memory demands of a long-lived
        program low. Mapped memory can never become `locked' between
        other chunks, as can happen with normally allocated chunks, which
        menas that even trimming via malloc_trim would not release them.
  
        However, it has the disadvantages that:
8bde7f776   wdenk   * Code cleanup:
741
742
743
744
745
746
747
748
749
  	 1. The space cannot be reclaimed, consolidated, and then
  	    used to service later requests, as happens with normal chunks.
  	 2. It can lead to more wastage because of mmap page alignment
  	    requirements
  	 3. It causes malloc performance to be more dependent on host
  	    system memory management support routines which may vary in
  	    implementation quality and may impose arbitrary
  	    limitations. Generally, servicing a request via normal
  	    malloc steps is faster than going through a system's mmap.
5b1d71372   wdenk   Initial revision
750
751
752
753
754
755
  
        All together, these considerations should lead you to use mmap
        only for relatively large requests.
  
  
  */
5b1d71372   wdenk   Initial revision
756
757
758
759
760
761
762
763
764
765
766
  #ifndef DEFAULT_MMAP_MAX
  #if HAVE_MMAP
  #define DEFAULT_MMAP_MAX       (64)
  #else
  #define DEFAULT_MMAP_MAX       (0)
  #endif
  #endif
  
  /*
      M_MMAP_MAX is the maximum number of requests to simultaneously
        service using mmap. This parameter exists because:
8bde7f776   wdenk   * Code cleanup:
767
768
769
770
771
772
773
774
775
  	 1. Some systems have a limited number of internal tables for
  	    use by mmap.
  	 2. In most systems, overreliance on mmap can degrade overall
  	    performance.
  	 3. If a program allocates many large regions, it is probably
  	    better off using normal sbrk-based allocation routines that
  	    can reclaim and reallocate normal heap memory. Using a
  	    small value allows transition into this mode after the
  	    first few allocations.
5b1d71372   wdenk   Initial revision
776
777
778
779
780
  
        Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
        the default value is 0, and attempts to set it to non-zero values
        in mallopt will fail.
  */
5b1d71372   wdenk   Initial revision
781
782
783
784
785
786
787
788
  /*
      USE_DL_PREFIX will prefix all public routines with the string 'dl'.
        Useful to quickly avoid procedure declaration conflicts and linker
        symbol conflicts with existing memory allocation routines.
  
  */
  
  /* #define USE_DL_PREFIX */
5b1d71372   wdenk   Initial revision
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
  /*
  
    Special defines for linux libc
  
    Except when compiled using these special defines for Linux libc
    using weak aliases, this malloc is NOT designed to work in
    multithreaded applications.  No semaphores or other concurrency
    control are provided to ensure that multiple malloc or free calls
    don't run at the same time, which could be disasterous. A single
    semaphore could be used across malloc, realloc, and free (which is
    essentially the effect of the linux weak alias approach). It would
    be hard to obtain finer granularity.
  
  */
  
  
  #ifdef INTERNAL_LINUX_C_LIB
  
  #if __STD_C
  
  Void_t * __default_morecore_init (ptrdiff_t);
  Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
  
  #else
  
  Void_t * __default_morecore_init ();
  Void_t *(*__morecore)() = __default_morecore_init;
  
  #endif
  
  #define MORECORE (*__morecore)
  #define MORECORE_FAILURE 0
  #define MORECORE_CLEARS 1
  
  #else /* INTERNAL_LINUX_C_LIB */
  
  #if __STD_C
  extern Void_t*     sbrk(ptrdiff_t);
  #else
  extern Void_t*     sbrk();
  #endif
  
  #ifndef MORECORE
  #define MORECORE sbrk
  #endif
  
  #ifndef MORECORE_FAILURE
  #define MORECORE_FAILURE -1
  #endif
  
  #ifndef MORECORE_CLEARS
  #define MORECORE_CLEARS 1
  #endif
  
  #endif /* INTERNAL_LINUX_C_LIB */
  
  #if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)
  
  #define cALLOc		__libc_calloc
  #define fREe		__libc_free
  #define mALLOc		__libc_malloc
  #define mEMALIGn	__libc_memalign
  #define rEALLOc		__libc_realloc
  #define vALLOc		__libc_valloc
  #define pvALLOc		__libc_pvalloc
  #define mALLINFo	__libc_mallinfo
  #define mALLOPt		__libc_mallopt
  
  #pragma weak calloc = __libc_calloc
  #pragma weak free = __libc_free
  #pragma weak cfree = __libc_free
  #pragma weak malloc = __libc_malloc
  #pragma weak memalign = __libc_memalign
  #pragma weak realloc = __libc_realloc
  #pragma weak valloc = __libc_valloc
  #pragma weak pvalloc = __libc_pvalloc
  #pragma weak mallinfo = __libc_mallinfo
  #pragma weak mallopt = __libc_mallopt
  
  #else
  
  #ifdef USE_DL_PREFIX
  #define cALLOc		dlcalloc
  #define fREe		dlfree
  #define mALLOc		dlmalloc
  #define mEMALIGn	dlmemalign
  #define rEALLOc		dlrealloc
  #define vALLOc		dlvalloc
  #define pvALLOc		dlpvalloc
  #define mALLINFo	dlmallinfo
  #define mALLOPt		dlmallopt
  #else /* USE_DL_PREFIX */
  #define cALLOc		calloc
  #define fREe		free
  #define mALLOc		malloc
  #define mEMALIGn	memalign
  #define rEALLOc		realloc
  #define vALLOc		valloc
  #define pvALLOc		pvalloc
  #define mALLINFo	mallinfo
  #define mALLOPt		mallopt
  #endif /* USE_DL_PREFIX */
  
  #endif
  
  /* Public routines */
  
  #if __STD_C
  
  Void_t* mALLOc(size_t);
  void    fREe(Void_t*);
  Void_t* rEALLOc(Void_t*, size_t);
  Void_t* mEMALIGn(size_t, size_t);
  Void_t* vALLOc(size_t);
  Void_t* pvALLOc(size_t);
  Void_t* cALLOc(size_t, size_t);
  void    cfree(Void_t*);
  int     malloc_trim(size_t);
  size_t  malloc_usable_size(Void_t*);
  void    malloc_stats(void);
  int     mALLOPt(int, int);
  struct mallinfo mALLINFo(void);
  #else
  Void_t* mALLOc();
  void    fREe();
  Void_t* rEALLOc();
  Void_t* mEMALIGn();
  Void_t* vALLOc();
  Void_t* pvALLOc();
  Void_t* cALLOc();
  void    cfree();
  int     malloc_trim();
  size_t  malloc_usable_size();
  void    malloc_stats();
  int     mALLOPt();
  struct mallinfo mALLINFo();
  #endif
  
  
  #ifdef __cplusplus
  };  /* end of extern "C" */
  #endif