source: SVN/rincon/u-boot/common/dlmalloc.src @ 55

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1/* ---------- 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 2.6.6  Sun Mar  5 19:10:03 2000  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 when the request
109       size is treaded as a long will return null.
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 if not WIN32)
193     Define this if your system does not have a <unistd.h>.
194  LACKS_SYS_PARAM_H         (default: undefined if not WIN32)
195     Define this if your system does not have a <sys/param.h>.
196  MORECORE                  (default: sbrk)
197     The name of the routine to call to obtain more memory from the system.
198  MORECORE_FAILURE          (default: -1)
199     The value returned upon failure of MORECORE.
200  MORECORE_CLEARS           (default 1)
201     True (1) if the routine mapped to MORECORE zeroes out memory (which
202     holds for sbrk).
203  DEFAULT_TRIM_THRESHOLD
204  DEFAULT_TOP_PAD
205  DEFAULT_MMAP_THRESHOLD
206  DEFAULT_MMAP_MAX
207     Default values of tunable parameters (described in detail below)
208     controlling interaction with host system routines (sbrk, mmap, etc).
209     These values may also be changed dynamically via mallopt(). The
210     preset defaults are those that give best performance for typical
211     programs/systems.
212  USE_DL_PREFIX             (default: undefined)
213     Prefix all public routines with the string 'dl'.  Useful to
214     quickly avoid procedure declaration conflicts and linker symbol
215     conflicts with existing memory allocation routines.
216
217
218*/
219
220
221
222
223/* Preliminaries */
224
225#ifndef __STD_C
226#ifdef __STDC__
227#define __STD_C     1
228#else
229#if __cplusplus
230#define __STD_C     1
231#else
232#define __STD_C     0
233#endif /*__cplusplus*/
234#endif /*__STDC__*/
235#endif /*__STD_C*/
236
237#ifndef Void_t
238#if (__STD_C || defined(WIN32))
239#define Void_t      void
240#else
241#define Void_t      char
242#endif
243#endif /*Void_t*/
244
245#if __STD_C
246#include <stddef.h>   /* for size_t */
247#else
248#include <sys/types.h>
249#endif
250
251#ifdef __cplusplus
252extern "C" {
253#endif
254
255#include <stdio.h>    /* needed for malloc_stats */
256
257
258/*
259  Compile-time options
260*/
261
262
263/*
264    Debugging:
265
266    Because freed chunks may be overwritten with link fields, this
267    malloc will often die when freed memory is overwritten by user
268    programs.  This can be very effective (albeit in an annoying way)
269    in helping track down dangling pointers.
270
271    If you compile with -DDEBUG, a number of assertion checks are
272    enabled that will catch more memory errors. You probably won't be
273    able to make much sense of the actual assertion errors, but they
274    should help you locate incorrectly overwritten memory.  The
275    checking is fairly extensive, and will slow down execution
276    noticeably. Calling malloc_stats or mallinfo with DEBUG set will
277    attempt to check every non-mmapped allocated and free chunk in the
278    course of computing the summmaries. (By nature, mmapped regions
279    cannot be checked very much automatically.)
280
281    Setting DEBUG may also be helpful if you are trying to modify
282    this code. The assertions in the check routines spell out in more
283    detail the assumptions and invariants underlying the algorithms.
284
285*/
286
287#if DEBUG
288#include <assert.h>
289#else
290#define assert(x) ((void)0)
291#endif
292
293
294/*
295  INTERNAL_SIZE_T is the word-size used for internal bookkeeping
296  of chunk sizes. On a 64-bit machine, you can reduce malloc
297  overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
298  at the expense of not being able to handle requests greater than
299  2^31. This limitation is hardly ever a concern; you are encouraged
300  to set this. However, the default version is the same as size_t.
301*/
302
303#ifndef INTERNAL_SIZE_T
304#define INTERNAL_SIZE_T size_t
305#endif
306
307/*
308  REALLOC_ZERO_BYTES_FREES should be set if a call to
309  realloc with zero bytes should be the same as a call to free.
310  Some people think it should. Otherwise, since this malloc
311  returns a unique pointer for malloc(0), so does realloc(p, 0).
312*/
313
314
315/*   #define REALLOC_ZERO_BYTES_FREES */
316
317
318/*
319  WIN32 causes an emulation of sbrk to be compiled in
320  mmap-based options are not currently supported in WIN32.
321*/
322
323/* #define WIN32 */
324#ifdef WIN32
325#define MORECORE wsbrk
326#define HAVE_MMAP 0
327
328#define LACKS_UNISTD_H
329#define LACKS_SYS_PARAM_H
330
331/*
332  Include 'windows.h' to get the necessary declarations for the
333  Microsoft Visual C++ data structures and routines used in the 'sbrk'
334  emulation.
335
336  Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft
337  Visual C++ header files are included.
338*/
339#define WIN32_LEAN_AND_MEAN
340#include <windows.h>
341#endif
342
343
344/*
345  HAVE_MEMCPY should be defined if you are not otherwise using
346  ANSI STD C, but still have memcpy and memset in your C library
347  and want to use them in calloc and realloc. Otherwise simple
348  macro versions are defined here.
349
350  USE_MEMCPY should be defined as 1 if you actually want to
351  have memset and memcpy called. People report that the macro
352  versions are often enough faster than libc versions on many
353  systems that it is better to use them.
354
355*/
356
357#define HAVE_MEMCPY
358
359#ifndef USE_MEMCPY
360#ifdef HAVE_MEMCPY
361#define USE_MEMCPY 1
362#else
363#define USE_MEMCPY 0
364#endif
365#endif
366
367#if (__STD_C || defined(HAVE_MEMCPY))
368
369#if __STD_C
370void* memset(void*, int, size_t);
371void* memcpy(void*, const void*, size_t);
372#else
373#ifdef WIN32
374/* On Win32 platforms, 'memset()' and 'memcpy()' are already declared in */
375/* 'windows.h' */
376#else
377Void_t* memset();
378Void_t* memcpy();
379#endif
380#endif
381#endif
382
383#if USE_MEMCPY
384
385/* The following macros are only invoked with (2n+1)-multiples of
386   INTERNAL_SIZE_T units, with a positive integer n. This is exploited
387   for fast inline execution when n is small. */
388
389#define MALLOC_ZERO(charp, nbytes)                                            \
390do {                                                                          \
391  INTERNAL_SIZE_T mzsz = (nbytes);                                            \
392  if(mzsz <= 9*sizeof(mzsz)) {                                                \
393    INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
394    if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
395                                     *mz++ = 0;                               \
396      if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
397                                     *mz++ = 0;                               \
398        if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
399                                     *mz++ = 0; }}}                           \
400                                     *mz++ = 0;                               \
401                                     *mz++ = 0;                               \
402                                     *mz   = 0;                               \
403  } else memset((charp), 0, mzsz);                                            \
404} while(0)
405
406#define MALLOC_COPY(dest,src,nbytes)                                          \
407do {                                                                          \
408  INTERNAL_SIZE_T mcsz = (nbytes);                                            \
409  if(mcsz <= 9*sizeof(mcsz)) {                                                \
410    INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
411    INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
412    if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
413                                     *mcdst++ = *mcsrc++;                     \
414      if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
415                                     *mcdst++ = *mcsrc++;                     \
416        if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
417                                     *mcdst++ = *mcsrc++; }}}                 \
418                                     *mcdst++ = *mcsrc++;                     \
419                                     *mcdst++ = *mcsrc++;                     \
420                                     *mcdst   = *mcsrc  ;                     \
421  } else memcpy(dest, src, mcsz);                                             \
422} while(0)
423
424#else /* !USE_MEMCPY */
425
426/* Use Duff's device for good zeroing/copying performance. */
427
428#define MALLOC_ZERO(charp, nbytes)                                            \
429do {                                                                          \
430  INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
431  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
432  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
433  switch (mctmp) {                                                            \
434    case 0: for(;;) { *mzp++ = 0;                                             \
435    case 7:           *mzp++ = 0;                                             \
436    case 6:           *mzp++ = 0;                                             \
437    case 5:           *mzp++ = 0;                                             \
438    case 4:           *mzp++ = 0;                                             \
439    case 3:           *mzp++ = 0;                                             \
440    case 2:           *mzp++ = 0;                                             \
441    case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
442  }                                                                           \
443} while(0)
444
445#define MALLOC_COPY(dest,src,nbytes)                                          \
446do {                                                                          \
447  INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
448  INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
449  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
450  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
451  switch (mctmp) {                                                            \
452    case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
453    case 7:           *mcdst++ = *mcsrc++;                                    \
454    case 6:           *mcdst++ = *mcsrc++;                                    \
455    case 5:           *mcdst++ = *mcsrc++;                                    \
456    case 4:           *mcdst++ = *mcsrc++;                                    \
457    case 3:           *mcdst++ = *mcsrc++;                                    \
458    case 2:           *mcdst++ = *mcsrc++;                                    \
459    case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
460  }                                                                           \
461} while(0)
462
463#endif
464
465
466/*
467  Define HAVE_MMAP to optionally make malloc() use mmap() to
468  allocate very large blocks.  These will be returned to the
469  operating system immediately after a free().
470*/
471
472#ifndef HAVE_MMAP
473#define HAVE_MMAP 1
474#endif
475
476/*
477  Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
478  large blocks.  This is currently only possible on Linux with
479  kernel versions newer than 1.3.77.
480*/
481
482#ifndef HAVE_MREMAP
483#ifdef INTERNAL_LINUX_C_LIB
484#define HAVE_MREMAP 1
485#else
486#define HAVE_MREMAP 0
487#endif
488#endif
489
490#if HAVE_MMAP
491
492#include <unistd.h>
493#include <fcntl.h>
494#include <sys/mman.h>
495
496#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
497#define MAP_ANONYMOUS MAP_ANON
498#endif
499
500#endif /* HAVE_MMAP */
501
502/*
503  Access to system page size. To the extent possible, this malloc
504  manages memory from the system in page-size units.
505
506  The following mechanics for getpagesize were adapted from
507  bsd/gnu getpagesize.h
508*/
509
510#ifndef LACKS_UNISTD_H
511#  include <unistd.h>
512#endif
513
514#ifndef malloc_getpagesize
515#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
516#    ifndef _SC_PAGE_SIZE
517#      define _SC_PAGE_SIZE _SC_PAGESIZE
518#    endif
519#  endif
520#  ifdef _SC_PAGE_SIZE
521#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
522#  else
523#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
524       extern size_t getpagesize();
525#      define malloc_getpagesize getpagesize()
526#    else
527#      ifdef WIN32
528#        define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */
529#      else
530#        ifndef LACKS_SYS_PARAM_H
531#          include <sys/param.h>
532#        endif
533#        ifdef EXEC_PAGESIZE
534#          define malloc_getpagesize EXEC_PAGESIZE
535#        else
536#          ifdef NBPG
537#            ifndef CLSIZE
538#              define malloc_getpagesize NBPG
539#            else
540#              define malloc_getpagesize (NBPG * CLSIZE)
541#            endif
542#          else
543#            ifdef NBPC
544#              define malloc_getpagesize NBPC
545#            else
546#              ifdef PAGESIZE
547#                define malloc_getpagesize PAGESIZE
548#              else
549#                define malloc_getpagesize (4096) /* just guess */
550#              endif
551#            endif
552#          endif
553#        endif
554#      endif
555#    endif
556#  endif
557#endif
558
559
560/*
561
562  This version of malloc supports the standard SVID/XPG mallinfo
563  routine that returns a struct containing the same kind of
564  information you can get from malloc_stats. It should work on
565  any SVID/XPG compliant system that has a /usr/include/malloc.h
566  defining struct mallinfo. (If you'd like to install such a thing
567  yourself, cut out the preliminary declarations as described above
568  and below and save them in a malloc.h file. But there's no
569  compelling reason to bother to do this.)
570
571  The main declaration needed is the mallinfo struct that is returned
572  (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
573  bunch of fields, most of which are not even meaningful in this
574  version of malloc. Some of these fields are are instead filled by
575  mallinfo() with other numbers that might possibly be of interest.
576
577  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
578  /usr/include/malloc.h file that includes a declaration of struct
579  mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
580  version is declared below.  These must be precisely the same for
581  mallinfo() to work.
582
583*/
584
585/* #define HAVE_USR_INCLUDE_MALLOC_H */
586
587#if HAVE_USR_INCLUDE_MALLOC_H
588#include "/usr/include/malloc.h"
589#else
590
591/* SVID2/XPG mallinfo structure */
592
593struct mallinfo {
594  int arena;    /* total space allocated from system */
595  int ordblks;  /* number of non-inuse chunks */
596  int smblks;   /* unused -- always zero */
597  int hblks;    /* number of mmapped regions */
598  int hblkhd;   /* total space in mmapped regions */
599  int usmblks;  /* unused -- always zero */
600  int fsmblks;  /* unused -- always zero */
601  int uordblks; /* total allocated space */
602  int fordblks; /* total non-inuse space */
603  int keepcost; /* top-most, releasable (via malloc_trim) space */
604};
605
606/* SVID2/XPG mallopt options */
607
608#define M_MXFAST  1    /* UNUSED in this malloc */
609#define M_NLBLKS  2    /* UNUSED in this malloc */
610#define M_GRAIN   3    /* UNUSED in this malloc */
611#define M_KEEP    4    /* UNUSED in this malloc */
612
613#endif
614
615/* mallopt options that actually do something */
616
617#define M_TRIM_THRESHOLD    -1
618#define M_TOP_PAD           -2
619#define M_MMAP_THRESHOLD    -3
620#define M_MMAP_MAX          -4
621
622
623#ifndef DEFAULT_TRIM_THRESHOLD
624#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
625#endif
626
627/*
628    M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
629      to keep before releasing via malloc_trim in free().
630
631      Automatic trimming is mainly useful in long-lived programs.
632      Because trimming via sbrk can be slow on some systems, and can
633      sometimes be wasteful (in cases where programs immediately
634      afterward allocate more large chunks) the value should be high
635      enough so that your overall system performance would improve by
636      releasing.
637
638      The trim threshold and the mmap control parameters (see below)
639      can be traded off with one another. Trimming and mmapping are
640      two different ways of releasing unused memory back to the
641      system. Between these two, it is often possible to keep
642      system-level demands of a long-lived program down to a bare
643      minimum. For example, in one test suite of sessions measuring
644      the XF86 X server on Linux, using a trim threshold of 128K and a
645      mmap threshold of 192K led to near-minimal long term resource
646      consumption.
647
648      If you are using this malloc in a long-lived program, it should
649      pay to experiment with these values.  As a rough guide, you
650      might set to a value close to the average size of a process
651      (program) running on your system.  Releasing this much memory
652      would allow such a process to run in memory.  Generally, it's
653      worth it to tune for trimming rather tham memory mapping when a
654      program undergoes phases where several large chunks are
655      allocated and released in ways that can reuse each other's
656      storage, perhaps mixed with phases where there are no such
657      chunks at all.  And in well-behaved long-lived programs,
658      controlling release of large blocks via trimming versus mapping
659      is usually faster.
660
661      However, in most programs, these parameters serve mainly as
662      protection against the system-level effects of carrying around
663      massive amounts of unneeded memory. Since frequent calls to
664      sbrk, mmap, and munmap otherwise degrade performance, the default
665      parameters are set to relatively high values that serve only as
666      safeguards.
667
668      The default trim value is high enough to cause trimming only in
669      fairly extreme (by current memory consumption standards) cases.
670      It must be greater than page size to have any useful effect.  To
671      disable trimming completely, you can set to (unsigned long)(-1);
672
673
674*/
675
676
677#ifndef DEFAULT_TOP_PAD
678#define DEFAULT_TOP_PAD        (0)
679#endif
680
681/*
682    M_TOP_PAD is the amount of extra `padding' space to allocate or
683      retain whenever sbrk is called. It is used in two ways internally:
684
685      * When sbrk is called to extend the top of the arena to satisfy
686        a new malloc request, this much padding is added to the sbrk
687        request.
688
689      * When malloc_trim is called automatically from free(),
690        it is used as the `pad' argument.
691
692      In both cases, the actual amount of padding is rounded
693      so that the end of the arena is always a system page boundary.
694
695      The main reason for using padding is to avoid calling sbrk so
696      often. Having even a small pad greatly reduces the likelihood
697      that nearly every malloc request during program start-up (or
698      after trimming) will invoke sbrk, which needlessly wastes
699      time.
700
701      Automatic rounding-up to page-size units is normally sufficient
702      to avoid measurable overhead, so the default is 0.  However, in
703      systems where sbrk is relatively slow, it can pay to increase
704      this value, at the expense of carrying around more memory than
705      the program needs.
706
707*/
708
709
710#ifndef DEFAULT_MMAP_THRESHOLD
711#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
712#endif
713
714/*
715
716    M_MMAP_THRESHOLD is the request size threshold for using mmap()
717      to service a request. Requests of at least this size that cannot
718      be allocated using already-existing space will be serviced via mmap.
719      (If enough normal freed space already exists it is used instead.)
720
721      Using mmap segregates relatively large chunks of memory so that
722      they can be individually obtained and released from the host
723      system. A request serviced through mmap is never reused by any
724      other request (at least not directly; the system may just so
725      happen to remap successive requests to the same locations).
726
727      Segregating space in this way has the benefit that mmapped space
728      can ALWAYS be individually released back to the system, which
729      helps keep the system level memory demands of a long-lived
730      program low. Mapped memory can never become `locked' between
731      other chunks, as can happen with normally allocated chunks, which
732      menas that even trimming via malloc_trim would not release them.
733
734      However, it has the disadvantages that:
735
736         1. The space cannot be reclaimed, consolidated, and then
737            used to service later requests, as happens with normal chunks.
738         2. It can lead to more wastage because of mmap page alignment
739            requirements
740         3. It causes malloc performance to be more dependent on host
741            system memory management support routines which may vary in
742            implementation quality and may impose arbitrary
743            limitations. Generally, servicing a request via normal
744            malloc steps is faster than going through a system's mmap.
745
746      All together, these considerations should lead you to use mmap
747      only for relatively large requests.
748
749
750*/
751
752
753#ifndef DEFAULT_MMAP_MAX
754#if HAVE_MMAP
755#define DEFAULT_MMAP_MAX       (64)
756#else
757#define DEFAULT_MMAP_MAX       (0)
758#endif
759#endif
760
761/*
762    M_MMAP_MAX is the maximum number of requests to simultaneously
763      service using mmap. This parameter exists because:
764
765         1. Some systems have a limited number of internal tables for
766            use by mmap.
767         2. In most systems, overreliance on mmap can degrade overall
768            performance.
769         3. If a program allocates many large regions, it is probably
770            better off using normal sbrk-based allocation routines that
771            can reclaim and reallocate normal heap memory. Using a
772            small value allows transition into this mode after the
773            first few allocations.
774
775      Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
776      the default value is 0, and attempts to set it to non-zero values
777      in mallopt will fail.
778*/
779
780
781/*
782    USE_DL_PREFIX will prefix all public routines with the string 'dl'.
783      Useful to quickly avoid procedure declaration conflicts and linker
784      symbol conflicts with existing memory allocation routines.
785
786*/
787
788/* #define USE_DL_PREFIX */
789
790
791/*
792
793  Special defines for linux libc
794
795  Except when compiled using these special defines for Linux libc
796  using weak aliases, this malloc is NOT designed to work in
797  multithreaded applications.  No semaphores or other concurrency
798  control are provided to ensure that multiple malloc or free calls
799  don't run at the same time, which could be disasterous. A single
800  semaphore could be used across malloc, realloc, and free (which is
801  essentially the effect of the linux weak alias approach). It would
802  be hard to obtain finer granularity.
803
804*/
805
806
807#ifdef INTERNAL_LINUX_C_LIB
808
809#if __STD_C
810
811Void_t * __default_morecore_init (ptrdiff_t);
812Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
813
814#else
815
816Void_t * __default_morecore_init ();
817Void_t *(*__morecore)() = __default_morecore_init;
818
819#endif
820
821#define MORECORE (*__morecore)
822#define MORECORE_FAILURE 0
823#define MORECORE_CLEARS 1
824
825#else /* INTERNAL_LINUX_C_LIB */
826
827#if __STD_C
828extern Void_t*     sbrk(ptrdiff_t);
829#else
830extern Void_t*     sbrk();
831#endif
832
833#ifndef MORECORE
834#define MORECORE sbrk
835#endif
836
837#ifndef MORECORE_FAILURE
838#define MORECORE_FAILURE -1
839#endif
840
841#ifndef MORECORE_CLEARS
842#define MORECORE_CLEARS 1
843#endif
844
845#endif /* INTERNAL_LINUX_C_LIB */
846
847#if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)
848
849#define cALLOc          __libc_calloc
850#define fREe            __libc_free
851#define mALLOc          __libc_malloc
852#define mEMALIGn        __libc_memalign
853#define rEALLOc         __libc_realloc
854#define vALLOc          __libc_valloc
855#define pvALLOc         __libc_pvalloc
856#define mALLINFo        __libc_mallinfo
857#define mALLOPt         __libc_mallopt
858
859#pragma weak calloc = __libc_calloc
860#pragma weak free = __libc_free
861#pragma weak cfree = __libc_free
862#pragma weak malloc = __libc_malloc
863#pragma weak memalign = __libc_memalign
864#pragma weak realloc = __libc_realloc
865#pragma weak valloc = __libc_valloc
866#pragma weak pvalloc = __libc_pvalloc
867#pragma weak mallinfo = __libc_mallinfo
868#pragma weak mallopt = __libc_mallopt
869
870#else
871
872#ifdef USE_DL_PREFIX
873#define cALLOc          dlcalloc
874#define fREe            dlfree
875#define mALLOc          dlmalloc
876#define mEMALIGn        dlmemalign
877#define rEALLOc         dlrealloc
878#define vALLOc          dlvalloc
879#define pvALLOc         dlpvalloc
880#define mALLINFo        dlmallinfo
881#define mALLOPt         dlmallopt
882#else /* USE_DL_PREFIX */
883#define cALLOc          calloc
884#define fREe            free
885#define mALLOc          malloc
886#define mEMALIGn        memalign
887#define rEALLOc         realloc
888#define vALLOc          valloc
889#define pvALLOc         pvalloc
890#define mALLINFo        mallinfo
891#define mALLOPt         mallopt
892#endif /* USE_DL_PREFIX */
893
894#endif
895
896/* Public routines */
897
898#if __STD_C
899
900Void_t* mALLOc(size_t);
901void    fREe(Void_t*);
902Void_t* rEALLOc(Void_t*, size_t);
903Void_t* mEMALIGn(size_t, size_t);
904Void_t* vALLOc(size_t);
905Void_t* pvALLOc(size_t);
906Void_t* cALLOc(size_t, size_t);
907void    cfree(Void_t*);
908int     malloc_trim(size_t);
909size_t  malloc_usable_size(Void_t*);
910void    malloc_stats();
911int     mALLOPt(int, int);
912struct mallinfo mALLINFo(void);
913#else
914Void_t* mALLOc();
915void    fREe();
916Void_t* rEALLOc();
917Void_t* mEMALIGn();
918Void_t* vALLOc();
919Void_t* pvALLOc();
920Void_t* cALLOc();
921void    cfree();
922int     malloc_trim();
923size_t  malloc_usable_size();
924void    malloc_stats();
925int     mALLOPt();
926struct mallinfo mALLINFo();
927#endif
928
929
930#ifdef __cplusplus
931};  /* end of extern "C" */
932#endif
933
934/* ---------- To make a malloc.h, end cutting here ------------ */
935
936
937/*
938  Emulation of sbrk for WIN32
939  All code within the ifdef WIN32 is untested by me.
940
941  Thanks to Martin Fong and others for supplying this.
942*/
943
944
945#ifdef WIN32
946
947#define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \
948~(malloc_getpagesize-1))
949#define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 1))
950
951/* resrve 64MB to insure large contiguous space */
952#define RESERVED_SIZE (1024*1024*64)
953#define NEXT_SIZE (2048*1024)
954#define TOP_MEMORY ((unsigned long)2*1024*1024*1024)
955
956struct GmListElement;
957typedef struct GmListElement GmListElement;
958
959struct GmListElement
960{
961        GmListElement* next;
962        void* base;
963};
964
965static GmListElement* head = 0;
966static unsigned int gNextAddress = 0;
967static unsigned int gAddressBase = 0;
968static unsigned int gAllocatedSize = 0;
969
970static
971GmListElement* makeGmListElement (void* bas)
972{
973        GmListElement* this;
974        this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement));
975        assert (this);
976        if (this)
977        {
978                this->base = bas;
979                this->next = head;
980                head = this;
981        }
982        return this;
983}
984
985void gcleanup ()
986{
987        BOOL rval;
988        assert ( (head == NULL) || (head->base == (void*)gAddressBase));
989        if (gAddressBase && (gNextAddress - gAddressBase))
990        {
991                rval = VirtualFree ((void*)gAddressBase,
992                                                        gNextAddress - gAddressBase,
993                                                        MEM_DECOMMIT);
994        assert (rval);
995        }
996        while (head)
997        {
998                GmListElement* next = head->next;
999                rval = VirtualFree (head->base, 0, MEM_RELEASE);
1000                assert (rval);
1001                LocalFree (head);
1002                head = next;
1003        }
1004}
1005
1006static
1007void* findRegion (void* start_address, unsigned long size)
1008{
1009        MEMORY_BASIC_INFORMATION info;
1010        if (size >= TOP_MEMORY) return NULL;
1011
1012        while ((unsigned long)start_address + size < TOP_MEMORY)
1013        {
1014                VirtualQuery (start_address, &info, sizeof (info));
1015                if ((info.State == MEM_FREE) && (info.RegionSize >= size))
1016                        return start_address;
1017                else
1018                {
1019                        /* Requested region is not available so see if the */
1020                        /* next region is available.  Set 'start_address' */
1021                        /* to the next region and call 'VirtualQuery()' */
1022                        /* again. */
1023
1024                        start_address = (char*)info.BaseAddress + info.RegionSize;
1025
1026                        /* Make sure we start looking for the next region */
1027                        /* on the *next* 64K boundary.  Otherwise, even if */
1028                        /* the new region is free according to */
1029                        /* 'VirtualQuery()', the subsequent call to */
1030                        /* 'VirtualAlloc()' (which follows the call to */
1031                        /* this routine in 'wsbrk()') will round *down* */
1032                        /* the requested address to a 64K boundary which */
1033                        /* we already know is an address in the */
1034                        /* unavailable region.  Thus, the subsequent call */
1035                        /* to 'VirtualAlloc()' will fail and bring us back */
1036                        /* here, causing us to go into an infinite loop. */
1037
1038                        start_address =
1039                                (void *) AlignPage64K((unsigned long) start_address);
1040                }
1041        }
1042        return NULL;
1043
1044}
1045
1046
1047void* wsbrk (long size)
1048{
1049        void* tmp;
1050        if (size > 0)
1051        {
1052                if (gAddressBase == 0)
1053                {
1054                        gAllocatedSize = max (RESERVED_SIZE, AlignPage (size));
1055                        gNextAddress = gAddressBase =
1056                                (unsigned int)VirtualAlloc (NULL, gAllocatedSize,
1057                                                                                        MEM_RESERVE, PAGE_NOACCESS);
1058                } else if (AlignPage (gNextAddress + size) > (gAddressBase +
1059gAllocatedSize))
1060                {
1061                        long new_size = max (NEXT_SIZE, AlignPage (size));
1062                        void* new_address = (void*)(gAddressBase+gAllocatedSize);
1063                        do
1064                        {
1065                                new_address = findRegion (new_address, new_size);
1066
1067                                if (new_address == 0)
1068                                        return (void*)-1;
1069
1070                                gAddressBase = gNextAddress =
1071                                        (unsigned int)VirtualAlloc (new_address, new_size,
1072                                                                                                MEM_RESERVE, PAGE_NOACCESS);
1073                                /* repeat in case of race condition */
1074                                /* The region that we found has been snagged */
1075                                /* by another thread */
1076                        }
1077                        while (gAddressBase == 0);
1078
1079                        assert (new_address == (void*)gAddressBase);
1080
1081                        gAllocatedSize = new_size;
1082
1083                        if (!makeGmListElement ((void*)gAddressBase))
1084                                return (void*)-1;
1085                }
1086                if ((size + gNextAddress) > AlignPage (gNextAddress))
1087                {
1088                        void* res;
1089                        res = VirtualAlloc ((void*)AlignPage (gNextAddress),
1090                                                                (size + gNextAddress -
1091                                                                 AlignPage (gNextAddress)),
1092                                                                MEM_COMMIT, PAGE_READWRITE);
1093                        if (res == 0)
1094                                return (void*)-1;
1095                }
1096                tmp = (void*)gNextAddress;
1097                gNextAddress = (unsigned int)tmp + size;
1098                return tmp;
1099        }
1100        else if (size < 0)
1101        {
1102                unsigned int alignedGoal = AlignPage (gNextAddress + size);
1103                /* Trim by releasing the virtual memory */
1104                if (alignedGoal >= gAddressBase)
1105                {
1106                        VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal,
1107                                                 MEM_DECOMMIT);
1108                        gNextAddress = gNextAddress + size;
1109                        return (void*)gNextAddress;
1110                }
1111                else
1112                {
1113                        VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase,
1114                                                 MEM_DECOMMIT);
1115                        gNextAddress = gAddressBase;
1116                        return (void*)-1;
1117                }
1118        }
1119        else
1120        {
1121                return (void*)gNextAddress;
1122        }
1123}
1124
1125#endif
1126
1127
1128
1129/*
1130  Type declarations
1131*/
1132
1133
1134struct malloc_chunk
1135{
1136  INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */
1137  INTERNAL_SIZE_T size;      /* Size in bytes, including overhead. */
1138  struct malloc_chunk* fd;   /* double links -- used only if free. */
1139  struct malloc_chunk* bk;
1140};
1141
1142typedef struct malloc_chunk* mchunkptr;
1143
1144/*
1145
1146   malloc_chunk details:
1147
1148    (The following includes lightly edited explanations by Colin Plumb.)
1149
1150    Chunks of memory are maintained using a `boundary tag' method as
1151    described in e.g., Knuth or Standish.  (See the paper by Paul
1152    Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
1153    survey of such techniques.)  Sizes of free chunks are stored both
1154    in the front of each chunk and at the end.  This makes
1155    consolidating fragmented chunks into bigger chunks very fast.  The
1156    size fields also hold bits representing whether chunks are free or
1157    in use.
1158
1159    An allocated chunk looks like this:
1160
1161
1162    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1163            |             Size of previous chunk, if allocated            | |
1164            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1165            |             Size of chunk, in bytes                         |P|
1166      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1167            |             User data starts here...                          .
1168            .                                                               .
1169            .             (malloc_usable_space() bytes)                     .
1170            .                                                               |
1171nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1172            |             Size of chunk                                     |
1173            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1174
1175
1176    Where "chunk" is the front of the chunk for the purpose of most of
1177    the malloc code, but "mem" is the pointer that is returned to the
1178    user.  "Nextchunk" is the beginning of the next contiguous chunk.
1179
1180    Chunks always begin on even word boundries, so the mem portion
1181    (which is returned to the user) is also on an even word boundary, and
1182    thus double-word aligned.
1183
1184    Free chunks are stored in circular doubly-linked lists, and look like this:
1185
1186    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1187            |             Size of previous chunk                            |
1188            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1189    `head:' |             Size of chunk, in bytes                         |P|
1190      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1191            |             Forward pointer to next chunk in list             |
1192            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1193            |             Back pointer to previous chunk in list            |
1194            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1195            |             Unused space (may be 0 bytes long)                .
1196            .                                                               .
1197            .                                                               |
1198nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1199    `foot:' |             Size of chunk, in bytes                           |
1200            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1201
1202    The P (PREV_INUSE) bit, stored in the unused low-order bit of the
1203    chunk size (which is always a multiple of two words), is an in-use
1204    bit for the *previous* chunk.  If that bit is *clear*, then the
1205    word before the current chunk size contains the previous chunk
1206    size, and can be used to find the front of the previous chunk.
1207    (The very first chunk allocated always has this bit set,
1208    preventing access to non-existent (or non-owned) memory.)
1209
1210    Note that the `foot' of the current chunk is actually represented
1211    as the prev_size of the NEXT chunk. (This makes it easier to
1212    deal with alignments etc).
1213
1214    The two exceptions to all this are
1215
1216     1. The special chunk `top', which doesn't bother using the
1217        trailing size field since there is no
1218        next contiguous chunk that would have to index off it. (After
1219        initialization, `top' is forced to always exist.  If it would
1220        become less than MINSIZE bytes long, it is replenished via
1221        malloc_extend_top.)
1222
1223     2. Chunks allocated via mmap, which have the second-lowest-order
1224        bit (IS_MMAPPED) set in their size fields.  Because they are
1225        never merged or traversed from any other chunk, they have no
1226        foot size or inuse information.
1227
1228    Available chunks are kept in any of several places (all declared below):
1229
1230    * `av': An array of chunks serving as bin headers for consolidated
1231       chunks. Each bin is doubly linked.  The bins are approximately
1232       proportionally (log) spaced.  There are a lot of these bins
1233       (128). This may look excessive, but works very well in
1234       practice.  All procedures maintain the invariant that no
1235       consolidated chunk physically borders another one. Chunks in
1236       bins are kept in size order, with ties going to the
1237       approximately least recently used chunk.
1238
1239       The chunks in each bin are maintained in decreasing sorted order by
1240       size.  This is irrelevant for the small bins, which all contain
1241       the same-sized chunks, but facilitates best-fit allocation for
1242       larger chunks. (These lists are just sequential. Keeping them in
1243       order almost never requires enough traversal to warrant using
1244       fancier ordered data structures.)  Chunks of the same size are
1245       linked with the most recently freed at the front, and allocations
1246       are taken from the back.  This results in LRU or FIFO allocation
1247       order, which tends to give each chunk an equal opportunity to be
1248       consolidated with adjacent freed chunks, resulting in larger free
1249       chunks and less fragmentation.
1250
1251    * `top': The top-most available chunk (i.e., the one bordering the
1252       end of available memory) is treated specially. It is never
1253       included in any bin, is used only if no other chunk is
1254       available, and is released back to the system if it is very
1255       large (see M_TRIM_THRESHOLD).
1256
1257    * `last_remainder': A bin holding only the remainder of the
1258       most recently split (non-top) chunk. This bin is checked
1259       before other non-fitting chunks, so as to provide better
1260       locality for runs of sequentially allocated chunks.
1261
1262    *  Implicitly, through the host system's memory mapping tables.
1263       If supported, requests greater than a threshold are usually
1264       serviced via calls to mmap, and then later released via munmap.
1265
1266*/
1267
1268
1269
1270
1271
1272/*  sizes, alignments */
1273
1274#define SIZE_SZ                (sizeof(INTERNAL_SIZE_T))
1275#define MALLOC_ALIGNMENT       (SIZE_SZ + SIZE_SZ)
1276#define MALLOC_ALIGN_MASK      (MALLOC_ALIGNMENT - 1)
1277#define MINSIZE                (sizeof(struct malloc_chunk))
1278
1279/* conversion from malloc headers to user pointers, and back */
1280
1281#define chunk2mem(p)   ((Void_t*)((char*)(p) + 2*SIZE_SZ))
1282#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
1283
1284/* pad request bytes into a usable size */
1285
1286#define request2size(req) \
1287 (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
1288  (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
1289   (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
1290
1291/* Check if m has acceptable alignment */
1292
1293#define aligned_OK(m)    (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
1294
1295
1296
1297
1298/*
1299  Physical chunk operations
1300*/
1301
1302
1303/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
1304
1305#define PREV_INUSE 0x1
1306
1307/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
1308
1309#define IS_MMAPPED 0x2
1310
1311/* Bits to mask off when extracting size */
1312
1313#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
1314
1315
1316/* Ptr to next physical malloc_chunk. */
1317
1318#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))
1319
1320/* Ptr to previous physical malloc_chunk */
1321
1322#define prev_chunk(p)\
1323   ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
1324
1325
1326/* Treat space at ptr + offset as a chunk */
1327
1328#define chunk_at_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
1329
1330
1331
1332
1333/*
1334  Dealing with use bits
1335*/
1336
1337/* extract p's inuse bit */
1338
1339#define inuse(p)\
1340((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)
1341
1342/* extract inuse bit of previous chunk */
1343
1344#define prev_inuse(p)  ((p)->size & PREV_INUSE)
1345
1346/* check for mmap()'ed chunk */
1347
1348#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
1349
1350/* set/clear chunk as in use without otherwise disturbing */
1351
1352#define set_inuse(p)\
1353((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE
1354
1355#define clear_inuse(p)\
1356((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)
1357
1358/* check/set/clear inuse bits in known places */
1359
1360#define inuse_bit_at_offset(p, s)\
1361 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
1362
1363#define set_inuse_bit_at_offset(p, s)\
1364 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
1365
1366#define clear_inuse_bit_at_offset(p, s)\
1367 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
1368
1369
1370
1371
1372/*
1373  Dealing with size fields
1374*/
1375
1376/* Get size, ignoring use bits */
1377
1378#define chunksize(p)          ((p)->size & ~(SIZE_BITS))
1379
1380/* Set size at head, without disturbing its use bit */
1381
1382#define set_head_size(p, s)   ((p)->size = (((p)->size & PREV_INUSE) | (s)))
1383
1384/* Set size/use ignoring previous bits in header */
1385
1386#define set_head(p, s)        ((p)->size = (s))
1387
1388/* Set size at footer (only when chunk is not in use) */
1389
1390#define set_foot(p, s)   (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
1391
1392
1393
1394
1395
1396/*
1397   Bins
1398
1399    The bins, `av_' are an array of pairs of pointers serving as the
1400    heads of (initially empty) doubly-linked lists of chunks, laid out
1401    in a way so that each pair can be treated as if it were in a
1402    malloc_chunk. (This way, the fd/bk offsets for linking bin heads
1403    and chunks are the same).
1404
1405    Bins for sizes < 512 bytes contain chunks of all the same size, spaced
1406    8 bytes apart. Larger bins are approximately logarithmically
1407    spaced. (See the table below.) The `av_' array is never mentioned
1408    directly in the code, but instead via bin access macros.
1409
1410    Bin layout:
1411
1412    64 bins of size       8
1413    32 bins of size      64
1414    16 bins of size     512
1415     8 bins of size    4096
1416     4 bins of size   32768
1417     2 bins of size  262144
1418     1 bin  of size what's left
1419
1420    There is actually a little bit of slop in the numbers in bin_index
1421    for the sake of speed. This makes no difference elsewhere.
1422
1423    The special chunks `top' and `last_remainder' get their own bins,
1424    (this is implemented via yet more trickery with the av_ array),
1425    although `top' is never properly linked to its bin since it is
1426    always handled specially.
1427
1428*/
1429
1430#define NAV             128   /* number of bins */
1431
1432typedef struct malloc_chunk* mbinptr;
1433
1434/* access macros */
1435
1436#define bin_at(i)      ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
1437#define next_bin(b)    ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
1438#define prev_bin(b)    ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))
1439
1440/*
1441   The first 2 bins are never indexed. The corresponding av_ cells are instead
1442   used for bookkeeping. This is not to save space, but to simplify
1443   indexing, maintain locality, and avoid some initialization tests.
1444*/
1445
1446#define top            (bin_at(0)->fd)   /* The topmost chunk */
1447#define last_remainder (bin_at(1))       /* remainder from last split */
1448
1449
1450/*
1451   Because top initially points to its own bin with initial
1452   zero size, thus forcing extension on the first malloc request,
1453   we avoid having any special code in malloc to check whether
1454   it even exists yet. But we still need to in malloc_extend_top.
1455*/
1456
1457#define initial_top    ((mchunkptr)(bin_at(0)))
1458
1459/* Helper macro to initialize bins */
1460
1461#define IAV(i)  bin_at(i), bin_at(i)
1462
1463static mbinptr av_[NAV * 2 + 2] = {
1464 0, 0,
1465 IAV(0),   IAV(1),   IAV(2),   IAV(3),   IAV(4),   IAV(5),   IAV(6),   IAV(7),
1466 IAV(8),   IAV(9),   IAV(10),  IAV(11),  IAV(12),  IAV(13),  IAV(14),  IAV(15),
1467 IAV(16),  IAV(17),  IAV(18),  IAV(19),  IAV(20),  IAV(21),  IAV(22),  IAV(23),
1468 IAV(24),  IAV(25),  IAV(26),  IAV(27),  IAV(28),  IAV(29),  IAV(30),  IAV(31),
1469 IAV(32),  IAV(33),  IAV(34),  IAV(35),  IAV(36),  IAV(37),  IAV(38),  IAV(39),
1470 IAV(40),  IAV(41),  IAV(42),  IAV(43),  IAV(44),  IAV(45),  IAV(46),  IAV(47),
1471 IAV(48),  IAV(49),  IAV(50),  IAV(51),  IAV(52),  IAV(53),  IAV(54),  IAV(55),
1472 IAV(56),  IAV(57),  IAV(58),  IAV(59),  IAV(60),  IAV(61),  IAV(62),  IAV(63),
1473 IAV(64),  IAV(65),  IAV(66),  IAV(67),  IAV(68),  IAV(69),  IAV(70),  IAV(71),
1474 IAV(72),  IAV(73),  IAV(74),  IAV(75),  IAV(76),  IAV(77),  IAV(78),  IAV(79),
1475 IAV(80),  IAV(81),  IAV(82),  IAV(83),  IAV(84),  IAV(85),  IAV(86),  IAV(87),
1476 IAV(88),  IAV(89),  IAV(90),  IAV(91),  IAV(92),  IAV(93),  IAV(94),  IAV(95),
1477 IAV(96),  IAV(97),  IAV(98),  IAV(99),  IAV(100), IAV(101), IAV(102), IAV(103),
1478 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
1479 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
1480 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
1481};
1482
1483
1484
1485/* field-extraction macros */
1486
1487#define first(b) ((b)->fd)
1488#define last(b)  ((b)->bk)
1489
1490/*
1491  Indexing into bins
1492*/
1493
1494#define bin_index(sz)                                                          \
1495(((((unsigned long)(sz)) >> 9) ==    0) ?       (((unsigned long)(sz)) >>  3): \
1496 ((((unsigned long)(sz)) >> 9) <=    4) ?  56 + (((unsigned long)(sz)) >>  6): \
1497 ((((unsigned long)(sz)) >> 9) <=   20) ?  91 + (((unsigned long)(sz)) >>  9): \
1498 ((((unsigned long)(sz)) >> 9) <=   84) ? 110 + (((unsigned long)(sz)) >> 12): \
1499 ((((unsigned long)(sz)) >> 9) <=  340) ? 119 + (((unsigned long)(sz)) >> 15): \
1500 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
1501                                          126)
1502/*
1503  bins for chunks < 512 are all spaced 8 bytes apart, and hold
1504  identically sized chunks. This is exploited in malloc.
1505*/
1506
1507#define MAX_SMALLBIN         63
1508#define MAX_SMALLBIN_SIZE   512
1509#define SMALLBIN_WIDTH        8
1510
1511#define smallbin_index(sz)  (((unsigned long)(sz)) >> 3)
1512
1513/*
1514   Requests are `small' if both the corresponding and the next bin are small
1515*/
1516
1517#define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)
1518
1519
1520
1521/*
1522    To help compensate for the large number of bins, a one-level index
1523    structure is used for bin-by-bin searching.  `binblocks' is a
1524    one-word bitvector recording whether groups of BINBLOCKWIDTH bins
1525    have any (possibly) non-empty bins, so they can be skipped over
1526    all at once during during traversals. The bits are NOT always
1527    cleared as soon as all bins in a block are empty, but instead only
1528    when all are noticed to be empty during traversal in malloc.
1529*/
1530
1531#define BINBLOCKWIDTH     4   /* bins per block */
1532
1533#define binblocks      (bin_at(0)->size) /* bitvector of nonempty blocks */
1534
1535/* bin<->block macros */
1536
1537#define idx2binblock(ix)    ((unsigned)1 << (ix / BINBLOCKWIDTH))
1538#define mark_binblock(ii)   (binblocks |= idx2binblock(ii))
1539#define clear_binblock(ii)  (binblocks &= ~(idx2binblock(ii)))
1540
1541
1542
1543
1544
1545/*  Other static bookkeeping data */
1546
1547/* variables holding tunable values */
1548
1549static unsigned long trim_threshold   = DEFAULT_TRIM_THRESHOLD;
1550static unsigned long top_pad          = DEFAULT_TOP_PAD;
1551static unsigned int  n_mmaps_max      = DEFAULT_MMAP_MAX;
1552static unsigned long mmap_threshold   = DEFAULT_MMAP_THRESHOLD;
1553
1554/* The first value returned from sbrk */
1555static char* sbrk_base = (char*)(-1);
1556
1557/* The maximum memory obtained from system via sbrk */
1558static unsigned long max_sbrked_mem = 0;
1559
1560/* The maximum via either sbrk or mmap */
1561static unsigned long max_total_mem = 0;
1562
1563/* internal working copy of mallinfo */
1564static struct mallinfo current_mallinfo = {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
1565
1566/* The total memory obtained from system via sbrk */
1567#define sbrked_mem  (current_mallinfo.arena)
1568
1569/* Tracking mmaps */
1570
1571static unsigned int n_mmaps = 0;
1572static unsigned int max_n_mmaps = 0;
1573static unsigned long mmapped_mem = 0;
1574static unsigned long max_mmapped_mem = 0;
1575
1576
1577
1578/*
1579  Debugging support
1580*/
1581
1582#if DEBUG
1583
1584
1585/*
1586  These routines make a number of assertions about the states
1587  of data structures that should be true at all times. If any
1588  are not true, it's very likely that a user program has somehow
1589  trashed memory. (It's also possible that there is a coding error
1590  in malloc. In which case, please report it!)
1591*/
1592
1593#if __STD_C
1594static void do_check_chunk(mchunkptr p)
1595#else
1596static void do_check_chunk(p) mchunkptr p;
1597#endif
1598{
1599  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1600
1601  /* No checkable chunk is mmapped */
1602  assert(!chunk_is_mmapped(p));
1603
1604  /* Check for legal address ... */
1605  assert((char*)p >= sbrk_base);
1606  if (p != top)
1607    assert((char*)p + sz <= (char*)top);
1608  else
1609    assert((char*)p + sz <= sbrk_base + sbrked_mem);
1610
1611}
1612
1613
1614#if __STD_C
1615static void do_check_free_chunk(mchunkptr p)
1616#else
1617static void do_check_free_chunk(p) mchunkptr p;
1618#endif
1619{
1620  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1621  mchunkptr next = chunk_at_offset(p, sz);
1622
1623  do_check_chunk(p);
1624
1625  /* Check whether it claims to be free ... */
1626  assert(!inuse(p));
1627
1628  /* Unless a special marker, must have OK fields */
1629  if ((long)sz >= (long)MINSIZE)
1630  {
1631    assert((sz & MALLOC_ALIGN_MASK) == 0);
1632    assert(aligned_OK(chunk2mem(p)));
1633    /* ... matching footer field */
1634    assert(next->prev_size == sz);
1635    /* ... and is fully consolidated */
1636    assert(prev_inuse(p));
1637    assert (next == top || inuse(next));
1638
1639    /* ... and has minimally sane links */
1640    assert(p->fd->bk == p);
1641    assert(p->bk->fd == p);
1642  }
1643  else /* markers are always of size SIZE_SZ */
1644    assert(sz == SIZE_SZ);
1645}
1646
1647#if __STD_C
1648static void do_check_inuse_chunk(mchunkptr p)
1649#else
1650static void do_check_inuse_chunk(p) mchunkptr p;
1651#endif
1652{
1653  mchunkptr next = next_chunk(p);
1654  do_check_chunk(p);
1655
1656  /* Check whether it claims to be in use ... */
1657  assert(inuse(p));
1658
1659  /* ... and is surrounded by OK chunks.
1660    Since more things can be checked with free chunks than inuse ones,
1661    if an inuse chunk borders them and debug is on, it's worth doing them.
1662  */
1663  if (!prev_inuse(p))
1664  {
1665    mchunkptr prv = prev_chunk(p);
1666    assert(next_chunk(prv) == p);
1667    do_check_free_chunk(prv);
1668  }
1669  if (next == top)
1670  {
1671    assert(prev_inuse(next));
1672    assert(chunksize(next) >= MINSIZE);
1673  }
1674  else if (!inuse(next))
1675    do_check_free_chunk(next);
1676
1677}
1678
1679#if __STD_C
1680static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
1681#else
1682static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
1683#endif
1684{
1685  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1686  long room = sz - s;
1687
1688  do_check_inuse_chunk(p);
1689
1690  /* Legal size ... */
1691  assert((long)sz >= (long)MINSIZE);
1692  assert((sz & MALLOC_ALIGN_MASK) == 0);
1693  assert(room >= 0);
1694  assert(room < (long)MINSIZE);
1695
1696  /* ... and alignment */
1697  assert(aligned_OK(chunk2mem(p)));
1698
1699
1700  /* ... and was allocated at front of an available chunk */
1701  assert(prev_inuse(p));
1702
1703}
1704
1705
1706#define check_free_chunk(P)  do_check_free_chunk(P)
1707#define check_inuse_chunk(P) do_check_inuse_chunk(P)
1708#define check_chunk(P) do_check_chunk(P)
1709#define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N)
1710#else
1711#define check_free_chunk(P)
1712#define check_inuse_chunk(P)
1713#define check_chunk(P)
1714#define check_malloced_chunk(P,N)
1715#endif
1716
1717
1718
1719/*
1720  Macro-based internal utilities
1721*/
1722
1723
1724/*
1725  Linking chunks in bin lists.
1726  Call these only with variables, not arbitrary expressions, as arguments.
1727*/
1728
1729/*
1730  Place chunk p of size s in its bin, in size order,
1731  putting it ahead of others of same size.
1732*/
1733
1734
1735#define frontlink(P, S, IDX, BK, FD)                                          \
1736{                                                                             \
1737  if (S < MAX_SMALLBIN_SIZE)                                                  \
1738  {                                                                           \
1739    IDX = smallbin_index(S);                                                  \
1740    mark_binblock(IDX);                                                       \
1741    BK = bin_at(IDX);                                                         \
1742    FD = BK->fd;                                                              \
1743    P->bk = BK;                                                               \
1744    P->fd = FD;                                                               \
1745    FD->bk = BK->fd = P;                                                      \
1746  }                                                                           \
1747  else                                                                        \
1748  {                                                                           \
1749    IDX = bin_index(S);                                                       \
1750    BK = bin_at(IDX);                                                         \
1751    FD = BK->fd;                                                              \
1752    if (FD == BK) mark_binblock(IDX);                                         \
1753    else                                                                      \
1754    {                                                                         \
1755      while (FD != BK && S < chunksize(FD)) FD = FD->fd;                      \
1756      BK = FD->bk;                                                            \
1757    }                                                                         \
1758    P->bk = BK;                                                               \
1759    P->fd = FD;                                                               \
1760    FD->bk = BK->fd = P;                                                      \
1761  }                                                                           \
1762}
1763
1764
1765/* take a chunk off a list */
1766
1767#define unlink(P, BK, FD)                                                     \
1768{                                                                             \
1769  BK = P->bk;                                                                 \
1770  FD = P->fd;                                                                 \
1771  FD->bk = BK;                                                                \
1772  BK->fd = FD;                                                                \
1773}                                                                             \
1774
1775/* Place p as the last remainder */
1776
1777#define link_last_remainder(P)                                                \
1778{                                                                             \
1779  last_remainder->fd = last_remainder->bk =  P;                               \
1780  P->fd = P->bk = last_remainder;                                             \
1781}
1782
1783/* Clear the last_remainder bin */
1784
1785#define clear_last_remainder \
1786  (last_remainder->fd = last_remainder->bk = last_remainder)
1787
1788
1789
1790
1791
1792/* Routines dealing with mmap(). */
1793
1794#if HAVE_MMAP
1795
1796#if __STD_C
1797static mchunkptr mmap_chunk(size_t size)
1798#else
1799static mchunkptr mmap_chunk(size) size_t size;
1800#endif
1801{
1802  size_t page_mask = malloc_getpagesize - 1;
1803  mchunkptr p;
1804
1805#ifndef MAP_ANONYMOUS
1806  static int fd = -1;
1807#endif
1808
1809  if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */
1810
1811  /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
1812   * there is no following chunk whose prev_size field could be used.
1813   */
1814  size = (size + SIZE_SZ + page_mask) & ~page_mask;
1815
1816#ifdef MAP_ANONYMOUS
1817  p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE,
1818                      MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
1819#else /* !MAP_ANONYMOUS */
1820  if (fd < 0)
1821  {
1822    fd = open("/dev/zero", O_RDWR);
1823    if(fd < 0) return 0;
1824  }
1825  p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
1826#endif
1827
1828  if(p == (mchunkptr)-1) return 0;
1829
1830  n_mmaps++;
1831  if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;
1832
1833  /* We demand that eight bytes into a page must be 8-byte aligned. */
1834  assert(aligned_OK(chunk2mem(p)));
1835
1836  /* The offset to the start of the mmapped region is stored
1837   * in the prev_size field of the chunk; normally it is zero,
1838   * but that can be changed in memalign().
1839   */
1840  p->prev_size = 0;
1841  set_head(p, size|IS_MMAPPED);
1842
1843  mmapped_mem += size;
1844  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1845    max_mmapped_mem = mmapped_mem;
1846  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1847    max_total_mem = mmapped_mem + sbrked_mem;
1848  return p;
1849}
1850
1851#if __STD_C
1852static void munmap_chunk(mchunkptr p)
1853#else
1854static void munmap_chunk(p) mchunkptr p;
1855#endif
1856{
1857  INTERNAL_SIZE_T size = chunksize(p);
1858  int ret;
1859
1860  assert (chunk_is_mmapped(p));
1861  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1862  assert((n_mmaps > 0));
1863  assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);
1864
1865  n_mmaps--;
1866  mmapped_mem -= (size + p->prev_size);
1867
1868  ret = munmap((char *)p - p->prev_size, size + p->prev_size);
1869
1870  /* munmap returns non-zero on failure */
1871  assert(ret == 0);
1872}
1873
1874#if HAVE_MREMAP
1875
1876#if __STD_C
1877static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
1878#else
1879static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
1880#endif
1881{
1882  size_t page_mask = malloc_getpagesize - 1;
1883  INTERNAL_SIZE_T offset = p->prev_size;
1884  INTERNAL_SIZE_T size = chunksize(p);
1885  char *cp;
1886
1887  assert (chunk_is_mmapped(p));
1888  assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1889  assert((n_mmaps > 0));
1890  assert(((size + offset) & (malloc_getpagesize-1)) == 0);
1891
1892  /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
1893  new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;
1894
1895  cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1);
1896
1897  if (cp == (char *)-1) return 0;
1898
1899  p = (mchunkptr)(cp + offset);
1900
1901  assert(aligned_OK(chunk2mem(p)));
1902
1903  assert((p->prev_size == offset));
1904  set_head(p, (new_size - offset)|IS_MMAPPED);
1905
1906  mmapped_mem -= size + offset;
1907  mmapped_mem += new_size;
1908  if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1909    max_mmapped_mem = mmapped_mem;
1910  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1911    max_total_mem = mmapped_mem + sbrked_mem;
1912  return p;
1913}
1914
1915#endif /* HAVE_MREMAP */
1916
1917#endif /* HAVE_MMAP */
1918
1919
1920
1921
1922/*
1923  Extend the top-most chunk by obtaining memory from system.
1924  Main interface to sbrk (but see also malloc_trim).
1925*/
1926
1927#if __STD_C
1928static void malloc_extend_top(INTERNAL_SIZE_T nb)
1929#else
1930static void malloc_extend_top(nb) INTERNAL_SIZE_T nb;
1931#endif
1932{
1933  char*     brk;                  /* return value from sbrk */
1934  INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
1935  INTERNAL_SIZE_T correction;     /* bytes for 2nd sbrk call */
1936  char*     new_brk;              /* return of 2nd sbrk call */
1937  INTERNAL_SIZE_T top_size;       /* new size of top chunk */
1938
1939  mchunkptr old_top     = top;  /* Record state of old top */
1940  INTERNAL_SIZE_T old_top_size = chunksize(old_top);
1941  char*     old_end      = (char*)(chunk_at_offset(old_top, old_top_size));
1942
1943  /* Pad request with top_pad plus minimal overhead */
1944
1945  INTERNAL_SIZE_T    sbrk_size     = nb + top_pad + MINSIZE;
1946  unsigned long pagesz    = malloc_getpagesize;
1947
1948  /* If not the first time through, round to preserve page boundary */
1949  /* Otherwise, we need to correct to a page size below anyway. */
1950  /* (We also correct below if an intervening foreign sbrk call.) */
1951
1952  if (sbrk_base != (char*)(-1))
1953    sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1);
1954
1955  brk = (char*)(MORECORE (sbrk_size));
1956
1957  /* Fail if sbrk failed or if a foreign sbrk call killed our space */
1958  if (brk == (char*)(MORECORE_FAILURE) ||
1959      (brk < old_end && old_top != initial_top))
1960    return;
1961
1962  sbrked_mem += sbrk_size;
1963
1964  if (brk == old_end) /* can just add bytes to current top */
1965  {
1966    top_size = sbrk_size + old_top_size;
1967    set_head(top, top_size | PREV_INUSE);
1968  }
1969  else
1970  {
1971    if (sbrk_base == (char*)(-1))  /* First time through. Record base */
1972      sbrk_base = brk;
1973    else  /* Someone else called sbrk().  Count those bytes as sbrked_mem. */
1974      sbrked_mem += brk - (char*)old_end;
1975
1976    /* Guarantee alignment of first new chunk made from this space */
1977    front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
1978    if (front_misalign > 0)
1979    {
1980      correction = (MALLOC_ALIGNMENT) - front_misalign;
1981      brk += correction;
1982    }
1983    else
1984      correction = 0;
1985
1986    /* Guarantee the next brk will be at a page boundary */
1987
1988    correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) &
1989                   ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size));
1990
1991    /* Allocate correction */
1992    new_brk = (char*)(MORECORE (correction));
1993    if (new_brk == (char*)(MORECORE_FAILURE)) return;
1994
1995    sbrked_mem += correction;
1996
1997    top = (mchunkptr)brk;
1998    top_size = new_brk - brk + correction;
1999    set_head(top, top_size | PREV_INUSE);
2000
2001    if (old_top != initial_top)
2002    {
2003
2004      /* There must have been an intervening foreign sbrk call. */
2005      /* A double fencepost is necessary to prevent consolidation */
2006
2007      /* If not enough space to do this, then user did something very wrong */
2008      if (old_top_size < MINSIZE)
2009      {
2010        set_head(top, PREV_INUSE); /* will force null return from malloc */
2011        return;
2012      }
2013
2014      /* Also keep size a multiple of MALLOC_ALIGNMENT */
2015      old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
2016      set_head_size(old_top, old_top_size);
2017      chunk_at_offset(old_top, old_top_size          )->size =
2018        SIZE_SZ|PREV_INUSE;
2019      chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size =
2020        SIZE_SZ|PREV_INUSE;
2021      /* If possible, release the rest. */
2022      if (old_top_size >= MINSIZE)
2023        fREe(chunk2mem(old_top));
2024    }
2025  }
2026
2027  if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
2028    max_sbrked_mem = sbrked_mem;
2029  if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
2030    max_total_mem = mmapped_mem + sbrked_mem;
2031
2032  /* We always land on a page boundary */
2033  assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0);
2034}
2035
2036
2037
2038
2039/* Main public routines */
2040
2041
2042/*
2043  Malloc Algorthim:
2044
2045    The requested size is first converted into a usable form, `nb'.
2046    This currently means to add 4 bytes overhead plus possibly more to
2047    obtain 8-byte alignment and/or to obtain a size of at least
2048    MINSIZE (currently 16 bytes), the smallest allocatable size.
2049    (All fits are considered `exact' if they are within MINSIZE bytes.)
2050
2051    From there, the first successful of the following steps is taken:
2052
2053      1. The bin corresponding to the request size is scanned, and if
2054         a chunk of exactly the right size is found, it is taken.
2055
2056      2. The most recently remaindered chunk is used if it is big
2057         enough.  This is a form of (roving) first fit, used only in
2058         the absence of exact fits. Runs of consecutive requests use
2059         the remainder of the chunk used for the previous such request
2060         whenever possible. This limited use of a first-fit style
2061         allocation strategy tends to give contiguous chunks
2062         coextensive lifetimes, which improves locality and can reduce
2063         fragmentation in the long run.
2064
2065      3. Other bins are scanned in increasing size order, using a
2066         chunk big enough to fulfill the request, and splitting off
2067         any remainder.  This search is strictly by best-fit; i.e.,
2068         the smallest (with ties going to approximately the least
2069         recently used) chunk that fits is selected.
2070
2071      4. If large enough, the chunk bordering the end of memory
2072         (`top') is split off. (This use of `top' is in accord with
2073         the best-fit search rule.  In effect, `top' is treated as
2074         larger (and thus less well fitting) than any other available
2075         chunk since it can be extended to be as large as necessary
2076         (up to system limitations).
2077
2078      5. If the request size meets the mmap threshold and the
2079         system supports mmap, and there are few enough currently
2080         allocated mmapped regions, and a call to mmap succeeds,
2081         the request is allocated via direct memory mapping.
2082
2083      6. Otherwise, the top of memory is extended by
2084         obtaining more space from the system (normally using sbrk,
2085         but definable to anything else via the MORECORE macro).
2086         Memory is gathered from the system (in system page-sized
2087         units) in a way that allows chunks obtained across different
2088         sbrk calls to be consolidated, but does not require
2089         contiguous memory. Thus, it should be safe to intersperse
2090         mallocs with other sbrk calls.
2091
2092
2093      All allocations are made from the the `lowest' part of any found
2094      chunk. (The implementation invariant is that prev_inuse is
2095      always true of any allocated chunk; i.e., that each allocated
2096      chunk borders either a previously allocated and still in-use chunk,
2097      or the base of its memory arena.)
2098
2099*/
2100
2101#if __STD_C
2102Void_t* mALLOc(size_t bytes)
2103#else
2104Void_t* mALLOc(bytes) size_t bytes;
2105#endif
2106{
2107  mchunkptr victim;                  /* inspected/selected chunk */
2108  INTERNAL_SIZE_T victim_size;       /* its size */
2109  int       idx;                     /* index for bin traversal */
2110  mbinptr   bin;                     /* associated bin */
2111  mchunkptr remainder;               /* remainder from a split */
2112  long      remainder_size;          /* its size */
2113  int       remainder_index;         /* its bin index */
2114  unsigned long block;               /* block traverser bit */
2115  int       startidx;                /* first bin of a traversed block */
2116  mchunkptr fwd;                     /* misc temp for linking */
2117  mchunkptr bck;                     /* misc temp for linking */
2118  mbinptr q;                         /* misc temp */
2119
2120  INTERNAL_SIZE_T nb;
2121
2122  if ((long)bytes < 0) return 0;
2123
2124  nb = request2size(bytes);  /* padded request size; */
2125
2126  /* Check for exact match in a bin */
2127
2128  if (is_small_request(nb))  /* Faster version for small requests */
2129  {
2130    idx = smallbin_index(nb);
2131
2132    /* No traversal or size check necessary for small bins.  */
2133
2134    q = bin_at(idx);
2135    victim = last(q);
2136
2137    /* Also scan the next one, since it would have a remainder < MINSIZE */
2138    if (victim == q)
2139    {
2140      q = next_bin(q);
2141      victim = last(q);
2142    }
2143    if (victim != q)
2144    {
2145      victim_size = chunksize(victim);
2146      unlink(victim, bck, fwd);
2147      set_inuse_bit_at_offset(victim, victim_size);
2148      check_malloced_chunk(victim, nb);
2149      return chunk2mem(victim);
2150    }
2151
2152    idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */
2153
2154  }
2155  else
2156  {
2157    idx = bin_index(nb);
2158    bin = bin_at(idx);
2159
2160    for (victim = last(bin); victim != bin; victim = victim->bk)
2161    {
2162      victim_size = chunksize(victim);
2163      remainder_size = victim_size - nb;
2164
2165      if (remainder_size >= (long)MINSIZE) /* too big */
2166      {
2167        --idx; /* adjust to rescan below after checking last remainder */
2168        break;
2169      }
2170
2171      else if (remainder_size >= 0) /* exact fit */
2172      {
2173        unlink(victim, bck, fwd);
2174        set_inuse_bit_at_offset(victim, victim_size);
2175        check_malloced_chunk(victim, nb);
2176        return chunk2mem(victim);
2177      }
2178    }
2179
2180    ++idx;
2181
2182  }
2183
2184  /* Try to use the last split-off remainder */
2185
2186  if ( (victim = last_remainder->fd) != last_remainder)
2187  {
2188    victim_size = chunksize(victim);
2189    remainder_size = victim_size - nb;
2190
2191    if (remainder_size >= (long)MINSIZE) /* re-split */
2192    {
2193      remainder = chunk_at_offset(victim, nb);
2194      set_head(victim, nb | PREV_INUSE);
2195      link_last_remainder(remainder);
2196      set_head(remainder, remainder_size | PREV_INUSE);
2197      set_foot(remainder, remainder_size);
2198      check_malloced_chunk(victim, nb);
2199      return chunk2mem(victim);
2200    }
2201
2202    clear_last_remainder;
2203
2204    if (remainder_size >= 0)  /* exhaust */
2205    {
2206      set_inuse_bit_at_offset(victim, victim_size);
2207      check_malloced_chunk(victim, nb);
2208      return chunk2mem(victim);
2209    }
2210
2211    /* Else place in bin */
2212
2213    frontlink(victim, victim_size, remainder_index, bck, fwd);
2214  }
2215
2216  /*
2217     If there are any possibly nonempty big-enough blocks,
2218     search for best fitting chunk by scanning bins in blockwidth units.
2219  */
2220
2221  if ( (block = idx2binblock(idx)) <= binblocks)
2222  {
2223
2224    /* Get to the first marked block */
2225
2226    if ( (block & binblocks) == 0)
2227    {
2228      /* force to an even block boundary */
2229      idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
2230      block <<= 1;
2231      while ((block & binblocks) == 0)
2232      {
2233        idx += BINBLOCKWIDTH;
2234        block <<= 1;
2235      }
2236    }
2237
2238    /* For each possibly nonempty block ... */
2239    for (;;)
2240    {
2241      startidx = idx;          /* (track incomplete blocks) */
2242      q = bin = bin_at(idx);
2243
2244      /* For each bin in this block ... */
2245      do
2246      {
2247        /* Find and use first big enough chunk ... */
2248
2249        for (victim = last(bin); victim != bin; victim = victim->bk)
2250        {
2251          victim_size = chunksize(victim);
2252          remainder_size = victim_size - nb;
2253
2254          if (remainder_size >= (long)MINSIZE) /* split */
2255          {
2256            remainder = chunk_at_offset(victim, nb);
2257            set_head(victim, nb | PREV_INUSE);
2258            unlink(victim, bck, fwd);
2259            link_last_remainder(remainder);
2260            set_head(remainder, remainder_size | PREV_INUSE);
2261            set_foot(remainder, remainder_size);
2262            check_malloced_chunk(victim, nb);
2263            return chunk2mem(victim);
2264          }
2265
2266          else if (remainder_size >= 0)  /* take */
2267          {
2268            set_inuse_bit_at_offset(victim, victim_size);
2269            unlink(victim, bck, fwd);
2270            check_malloced_chunk(victim, nb);
2271            return chunk2mem(victim);
2272          }
2273
2274        }
2275
2276       bin = next_bin(bin);
2277
2278      } while ((++idx & (BINBLOCKWIDTH - 1)) != 0);
2279
2280      /* Clear out the block bit. */
2281
2282      do   /* Possibly backtrack to try to clear a partial block */
2283      {
2284        if ((startidx & (BINBLOCKWIDTH - 1)) == 0)
2285        {
2286          binblocks &= ~block;
2287          break;
2288        }
2289        --startidx;
2290       q = prev_bin(q);
2291      } while (first(q) == q);
2292
2293      /* Get to the next possibly nonempty block */
2294
2295      if ( (block <<= 1) <= binblocks && (block != 0) )
2296      {
2297        while ((block & binblocks) == 0)
2298        {
2299          idx += BINBLOCKWIDTH;
2300          block <<= 1;
2301        }
2302      }
2303      else
2304        break;
2305    }
2306  }
2307
2308
2309  /* Try to use top chunk */
2310
2311  /* Require that there be a remainder, ensuring top always exists  */
2312  if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
2313  {
2314
2315#if HAVE_MMAP
2316    /* If big and would otherwise need to extend, try to use mmap instead */
2317    if ((unsigned long)nb >= (unsigned long)mmap_threshold &&
2318        (victim = mmap_chunk(nb)) != 0)
2319      return chunk2mem(victim);
2320#endif
2321
2322    /* Try to extend */
2323    malloc_extend_top(nb);
2324    if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
2325      return 0; /* propagate failure */
2326  }
2327
2328  victim = top;
2329  set_head(victim, nb | PREV_INUSE);
2330  top = chunk_at_offset(victim, nb);
2331  set_head(top, remainder_size | PREV_INUSE);
2332  check_malloced_chunk(victim, nb);
2333  return chunk2mem(victim);
2334
2335}
2336
2337
2338
2339
2340/*
2341
2342  free() algorithm :
2343
2344    cases:
2345
2346       1. free(0) has no effect.
2347
2348       2. If the chunk was allocated via mmap, it is release via munmap().
2349
2350       3. If a returned chunk borders the current high end of memory,
2351          it is consolidated into the top, and if the total unused
2352          topmost memory exceeds the trim threshold, malloc_trim is
2353          called.
2354
2355       4. Other chunks are consolidated as they arrive, and
2356          placed in corresponding bins. (This includes the case of
2357          consolidating with the current `last_remainder').
2358
2359*/
2360
2361
2362#if __STD_C
2363void fREe(Void_t* mem)
2364#else
2365void fREe(mem) Void_t* mem;
2366#endif
2367{
2368  mchunkptr p;         /* chunk corresponding to mem */
2369  INTERNAL_SIZE_T hd;  /* its head field */
2370  INTERNAL_SIZE_T sz;  /* its size */
2371  int       idx;       /* its bin index */
2372  mchunkptr next;      /* next contiguous chunk */
2373  INTERNAL_SIZE_T nextsz; /* its size */
2374  INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */
2375  mchunkptr bck;       /* misc temp for linking */
2376  mchunkptr fwd;       /* misc temp for linking */
2377  int       islr;      /* track whether merging with last_remainder */
2378
2379  if (mem == 0)                              /* free(0) has no effect */
2380    return;
2381
2382  p = mem2chunk(mem);
2383  hd = p->size;
2384
2385#if HAVE_MMAP
2386  if (hd & IS_MMAPPED)                       /* release mmapped memory. */
2387  {
2388    munmap_chunk(p);
2389    return;
2390  }
2391#endif
2392
2393  check_inuse_chunk(p);
2394
2395  sz = hd & ~PREV_INUSE;
2396  next = chunk_at_offset(p, sz);
2397  nextsz = chunksize(next);
2398
2399  if (next == top)                            /* merge with top */
2400  {
2401    sz += nextsz;
2402
2403    if (!(hd & PREV_INUSE))                    /* consolidate backward */
2404    {
2405      prevsz = p->prev_size;
2406      p = chunk_at_offset(p, -((long) prevsz));
2407      sz += prevsz;
2408      unlink(p, bck, fwd);
2409    }
2410
2411    set_head(p, sz | PREV_INUSE);
2412    top = p;
2413    if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
2414      malloc_trim(top_pad);
2415    return;
2416  }
2417
2418  set_head(next, nextsz);                    /* clear inuse bit */
2419
2420  islr = 0;
2421
2422  if (!(hd & PREV_INUSE))                    /* consolidate backward */
2423  {
2424    prevsz = p->prev_size;
2425    p = chunk_at_offset(p, -((long) prevsz));
2426    sz += prevsz;
2427
2428    if (p->fd == last_remainder)             /* keep as last_remainder */
2429      islr = 1;
2430    else
2431      unlink(p, bck, fwd);
2432  }
2433
2434  if (!(inuse_bit_at_offset(next, nextsz)))   /* consolidate forward */
2435  {
2436    sz += nextsz;
2437
2438    if (!islr && next->fd == last_remainder)  /* re-insert last_remainder */
2439    {
2440      islr = 1;
2441      link_last_remainder(p);
2442    }
2443    else
2444      unlink(next, bck, fwd);
2445  }
2446
2447
2448  set_head(p, sz | PREV_INUSE);
2449  set_foot(p, sz);
2450  if (!islr)
2451    frontlink(p, sz, idx, bck, fwd);
2452}
2453
2454
2455
2456
2457
2458/*
2459
2460  Realloc algorithm:
2461
2462    Chunks that were obtained via mmap cannot be extended or shrunk
2463    unless HAVE_MREMAP is defined, in which case mremap is used.
2464    Otherwise, if their reallocation is for additional space, they are
2465    copied.  If for less, they are just left alone.
2466
2467    Otherwise, if the reallocation is for additional space, and the
2468    chunk can be extended, it is, else a malloc-copy-free sequence is
2469    taken.  There are several different ways that a chunk could be
2470    extended. All are tried:
2471
2472       * Extending forward into following adjacent free chunk.
2473       * Shifting backwards, joining preceding adjacent space
2474       * Both shifting backwards and extending forward.
2475       * Extending into newly sbrked space
2476
2477    Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
2478    size argument of zero (re)allocates a minimum-sized chunk.
2479
2480    If the reallocation is for less space, and the new request is for
2481    a `small' (<512 bytes) size, then the newly unused space is lopped
2482    off and freed.
2483
2484    The old unix realloc convention of allowing the last-free'd chunk
2485    to be used as an argument to realloc is no longer supported.
2486    I don't know of any programs still relying on this feature,
2487    and allowing it would also allow too many other incorrect
2488    usages of realloc to be sensible.
2489
2490
2491*/
2492
2493
2494#if __STD_C
2495Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
2496#else
2497Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
2498#endif
2499{
2500  INTERNAL_SIZE_T    nb;      /* padded request size */
2501
2502  mchunkptr oldp;             /* chunk corresponding to oldmem */
2503  INTERNAL_SIZE_T    oldsize; /* its size */
2504
2505  mchunkptr newp;             /* chunk to return */
2506  INTERNAL_SIZE_T    newsize; /* its size */
2507  Void_t*   newmem;           /* corresponding user mem */
2508
2509  mchunkptr next;             /* next contiguous chunk after oldp */
2510  INTERNAL_SIZE_T  nextsize;  /* its size */
2511
2512  mchunkptr prev;             /* previous contiguous chunk before oldp */
2513  INTERNAL_SIZE_T  prevsize;  /* its size */
2514
2515  mchunkptr remainder;        /* holds split off extra space from newp */
2516  INTERNAL_SIZE_T  remainder_size;   /* its size */
2517
2518  mchunkptr bck;              /* misc temp for linking */
2519  mchunkptr fwd;              /* misc temp for linking */
2520
2521#ifdef REALLOC_ZERO_BYTES_FREES
2522  if (bytes == 0) { fREe(oldmem); return 0; }
2523#endif
2524
2525  if ((long)bytes < 0) return 0;
2526
2527  /* realloc of null is supposed to be same as malloc */
2528  if (oldmem == 0) return mALLOc(bytes);
2529
2530  newp    = oldp    = mem2chunk(oldmem);
2531  newsize = oldsize = chunksize(oldp);
2532
2533
2534  nb = request2size(bytes);
2535
2536#if HAVE_MMAP
2537  if (chunk_is_mmapped(oldp))
2538  {
2539#if HAVE_MREMAP
2540    newp = mremap_chunk(oldp, nb);
2541    if(newp) return chunk2mem(newp);
2542#endif
2543    /* Note the extra SIZE_SZ overhead. */
2544    if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
2545    /* Must alloc, copy, free. */
2546    newmem = mALLOc(bytes);
2547    if (newmem == 0) return 0; /* propagate failure */
2548    MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
2549    munmap_chunk(oldp);
2550    return newmem;
2551  }
2552#endif
2553
2554  check_inuse_chunk(oldp);
2555
2556  if ((long)(oldsize) < (long)(nb))
2557  {
2558
2559    /* Try expanding forward */
2560
2561    next = chunk_at_offset(oldp, oldsize);
2562    if (next == top || !inuse(next))
2563    {
2564      nextsize = chunksize(next);
2565
2566      /* Forward into top only if a remainder */
2567      if (next == top)
2568      {
2569        if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE))
2570        {
2571          newsize += nextsize;
2572          top = chunk_at_offset(oldp, nb);
2573          set_head(top, (newsize - nb) | PREV_INUSE);
2574          set_head_size(oldp, nb);
2575          return chunk2mem(oldp);
2576        }
2577      }
2578
2579      /* Forward into next chunk */
2580      else if (((long)(nextsize + newsize) >= (long)(nb)))
2581      {
2582        unlink(next, bck, fwd);
2583        newsize  += nextsize;
2584        goto split;
2585      }
2586    }
2587    else
2588    {
2589      next = 0;
2590      nextsize = 0;
2591    }
2592
2593    /* Try shifting backwards. */
2594
2595    if (!prev_inuse(oldp))
2596    {
2597      prev = prev_chunk(oldp);
2598      prevsize = chunksize(prev);
2599
2600      /* try forward + backward first to save a later consolidation */
2601
2602      if (next != 0)
2603      {
2604        /* into top */
2605        if (next == top)
2606        {
2607          if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE))
2608          {
2609            unlink(prev, bck, fwd);
2610            newp = prev;
2611            newsize += prevsize + nextsize;
2612            newmem = chunk2mem(newp);
2613            MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2614            top = chunk_at_offset(newp, nb);
2615            set_head(top, (newsize - nb) | PREV_INUSE);
2616            set_head_size(newp, nb);
2617            return newmem;
2618          }
2619        }
2620
2621        /* into next chunk */
2622        else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
2623        {
2624          unlink(next, bck, fwd);
2625          unlink(prev, bck, fwd);
2626          newp = prev;
2627          newsize += nextsize + prevsize;
2628          newmem = chunk2mem(newp);
2629          MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2630          goto split;
2631        }
2632      }
2633
2634      /* backward only */
2635      if (prev != 0 && (long)(prevsize + newsize) >= (long)nb)
2636      {
2637        unlink(prev, bck, fwd);
2638        newp = prev;
2639        newsize += prevsize;
2640        newmem = chunk2mem(newp);
2641        MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2642        goto split;
2643      }
2644    }
2645
2646    /* Must allocate */
2647
2648    newmem = mALLOc (bytes);
2649
2650    if (newmem == 0)  /* propagate failure */
2651      return 0;
2652
2653    /* Avoid copy if newp is next chunk after oldp. */
2654    /* (This can only happen when new chunk is sbrk'ed.) */
2655
2656    if ( (newp = mem2chunk(newmem)) == next_chunk(oldp))
2657    {
2658      newsize += chunksize(newp);
2659      newp = oldp;
2660      goto split;
2661    }
2662
2663    /* Otherwise copy, free, and exit */
2664    MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2665    fREe(oldmem);
2666    return newmem;
2667  }
2668
2669
2670 split:  /* split off extra room in old or expanded chunk */
2671
2672  if (newsize - nb >= MINSIZE) /* split off remainder */
2673  {
2674    remainder = chunk_at_offset(newp, nb);
2675    remainder_size = newsize - nb;
2676    set_head_size(newp, nb);
2677    set_head(remainder, remainder_size | PREV_INUSE);
2678    set_inuse_bit_at_offset(remainder, remainder_size);
2679    fREe(chunk2mem(remainder)); /* let free() deal with it */
2680  }
2681  else
2682  {
2683    set_head_size(newp, newsize);
2684    set_inuse_bit_at_offset(newp, newsize);
2685  }
2686
2687  check_inuse_chunk(newp);
2688  return chunk2mem(newp);
2689}
2690
2691
2692
2693
2694/*
2695
2696  memalign algorithm:
2697
2698    memalign requests more than enough space from malloc, finds a spot
2699    within that chunk that meets the alignment request, and then
2700    possibly frees the leading and trailing space.
2701
2702    The alignment argument must be a power of two. This property is not
2703    checked by memalign, so misuse may result in random runtime errors.
2704
2705    8-byte alignment is guaranteed by normal malloc calls, so don't
2706    bother calling memalign with an argument of 8 or less.
2707
2708    Overreliance on memalign is a sure way to fragment space.
2709
2710*/
2711
2712
2713#if __STD_C
2714Void_t* mEMALIGn(size_t alignment, size_t bytes)
2715#else
2716Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
2717#endif
2718{
2719  INTERNAL_SIZE_T    nb;      /* padded  request size */
2720  char*     m;                /* memory returned by malloc call */
2721  mchunkptr p;                /* corresponding chunk */
2722  char*     brk;              /* alignment point within p */
2723  mchunkptr newp;             /* chunk to return */
2724  INTERNAL_SIZE_T  newsize;   /* its size */
2725  INTERNAL_SIZE_T  leadsize;  /* leading space befor alignment point */
2726  mchunkptr remainder;        /* spare room at end to split off */
2727  long      remainder_size;   /* its size */
2728
2729  if ((long)bytes < 0) return 0;
2730
2731  /* If need less alignment than we give anyway, just relay to malloc */
2732
2733  if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);
2734
2735  /* Otherwise, ensure that it is at least a minimum chunk size */
2736
2737  if (alignment <  MINSIZE) alignment = MINSIZE;
2738
2739  /* Call malloc with worst case padding to hit alignment. */
2740
2741  nb = request2size(bytes);
2742  m  = (char*)(mALLOc(nb + alignment + MINSIZE));
2743
2744  if (m == 0) return 0; /* propagate failure */
2745
2746  p = mem2chunk(m);
2747
2748  if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
2749  {
2750#if HAVE_MMAP
2751    if(chunk_is_mmapped(p))
2752      return chunk2mem(p); /* nothing more to do */
2753#endif
2754  }
2755  else /* misaligned */
2756  {
2757    /*
2758      Find an aligned spot inside chunk.
2759      Since we need to give back leading space in a chunk of at
2760      least MINSIZE, if the first calculation places us at
2761      a spot with less than MINSIZE leader, we can move to the
2762      next aligned spot -- we've allocated enough total room so that
2763      this is always possible.
2764    */
2765
2766    brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment));
2767    if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment;
2768
2769    newp = (mchunkptr)brk;
2770    leadsize = brk - (char*)(p);
2771    newsize = chunksize(p) - leadsize;
2772
2773#if HAVE_MMAP
2774    if(chunk_is_mmapped(p))
2775    {
2776      newp->prev_size = p->prev_size + leadsize;
2777      set_head(newp, newsize|IS_MMAPPED);
2778      return chunk2mem(newp);
2779    }
2780#endif
2781
2782    /* give back leader, use the rest */
2783
2784    set_head(newp, newsize | PREV_INUSE);
2785    set_inuse_bit_at_offset(newp, newsize);
2786    set_head_size(p, leadsize);
2787    fREe(chunk2mem(p));
2788    p = newp;
2789
2790    assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0);
2791  }
2792
2793  /* Also give back spare room at the end */
2794
2795  remainder_size = chunksize(p) - nb;
2796
2797  if (remainder_size >= (long)MINSIZE)
2798  {
2799    remainder = chunk_at_offset(p, nb);
2800    set_head(remainder, remainder_size | PREV_INUSE);
2801    set_head_size(p, nb);
2802    fREe(chunk2mem(remainder));
2803  }
2804
2805  check_inuse_chunk(p);
2806  return chunk2mem(p);
2807
2808}
2809
2810
2811
2812
2813/*
2814    valloc just invokes memalign with alignment argument equal
2815    to the page size of the system (or as near to this as can
2816    be figured out from all the includes/defines above.)
2817*/
2818
2819#if __STD_C
2820Void_t* vALLOc(size_t bytes)
2821#else
2822Void_t* vALLOc(bytes) size_t bytes;
2823#endif
2824{
2825  return mEMALIGn (malloc_getpagesize, bytes);
2826}
2827
2828/*
2829  pvalloc just invokes valloc for the nearest pagesize
2830  that will accommodate request
2831*/
2832
2833
2834#if __STD_C
2835Void_t* pvALLOc(size_t bytes)
2836#else
2837Void_t* pvALLOc(bytes) size_t bytes;
2838#endif
2839{
2840  size_t pagesize = malloc_getpagesize;
2841  return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
2842}
2843
2844/*
2845
2846  calloc calls malloc, then zeroes out the allocated chunk.
2847
2848*/
2849
2850#if __STD_C
2851Void_t* cALLOc(size_t n, size_t elem_size)
2852#else
2853Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
2854#endif
2855{
2856  mchunkptr p;
2857  INTERNAL_SIZE_T csz;
2858
2859  INTERNAL_SIZE_T sz = n * elem_size;
2860
2861
2862  /* check if expand_top called, in which case don't need to clear */
2863#if MORECORE_CLEARS
2864  mchunkptr oldtop = top;
2865  INTERNAL_SIZE_T oldtopsize = chunksize(top);
2866#endif
2867  Void_t* mem = mALLOc (sz);
2868
2869  if ((long)n < 0) return 0;
2870
2871  if (mem == 0)
2872    return 0;
2873  else
2874  {
2875    p = mem2chunk(mem);
2876
2877    /* Two optional cases in which clearing not necessary */
2878
2879
2880#if HAVE_MMAP
2881    if (chunk_is_mmapped(p)) return mem;
2882#endif
2883
2884    csz = chunksize(p);
2885
2886#if MORECORE_CLEARS
2887    if (p == oldtop && csz > oldtopsize)
2888    {
2889      /* clear only the bytes from non-freshly-sbrked memory */
2890      csz = oldtopsize;
2891    }
2892#endif
2893
2894    MALLOC_ZERO(mem, csz - SIZE_SZ);
2895    return mem;
2896  }
2897}
2898
2899/*
2900
2901  cfree just calls free. It is needed/defined on some systems
2902  that pair it with calloc, presumably for odd historical reasons.
2903
2904*/
2905
2906#if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__)
2907#if __STD_C
2908void cfree(Void_t *mem)
2909#else
2910void cfree(mem) Void_t *mem;
2911#endif
2912{
2913  fREe(mem);
2914}
2915#endif
2916
2917
2918
2919/*
2920
2921    Malloc_trim gives memory back to the system (via negative
2922    arguments to sbrk) if there is unused memory at the `high' end of
2923    the malloc pool. You can call this after freeing large blocks of
2924    memory to potentially reduce the system-level memory requirements
2925    of a program. However, it cannot guarantee to reduce memory. Under
2926    some allocation patterns, some large free blocks of memory will be
2927    locked between two used chunks, so they cannot be given back to
2928    the system.
2929
2930    The `pad' argument to malloc_trim represents the amount of free
2931    trailing space to leave untrimmed. If this argument is zero,
2932    only the minimum amount of memory to maintain internal data
2933    structures will be left (one page or less). Non-zero arguments
2934    can be supplied to maintain enough trailing space to service
2935    future expected allocations without having to re-obtain memory
2936    from the system.
2937
2938    Malloc_trim returns 1 if it actually released any memory, else 0.
2939
2940*/
2941
2942#if __STD_C
2943int malloc_trim(size_t pad)
2944#else
2945int malloc_trim(pad) size_t pad;
2946#endif
2947{
2948  long  top_size;        /* Amount of top-most memory */
2949  long  extra;           /* Amount to release */
2950  char* current_brk;     /* address returned by pre-check sbrk call */
2951  char* new_brk;         /* address returned by negative sbrk call */
2952
2953  unsigned long pagesz = malloc_getpagesize;
2954
2955  top_size = chunksize(top);
2956  extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
2957
2958  if (extra < (long)pagesz)  /* Not enough memory to release */
2959    return 0;
2960
2961  else
2962  {
2963    /* Test to make sure no one else called sbrk */
2964    current_brk = (char*)(MORECORE (0));
2965    if (current_brk != (char*)(top) + top_size)
2966      return 0;     /* Apparently we don't own memory; must fail */
2967
2968    else
2969    {
2970      new_brk = (char*)(MORECORE (-extra));
2971
2972      if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */
2973      {
2974        /* Try to figure out what we have */
2975        current_brk = (char*)(MORECORE (0));
2976        top_size = current_brk - (char*)top;
2977        if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
2978        {
2979          sbrked_mem = current_brk - sbrk_base;
2980          set_head(top, top_size | PREV_INUSE);
2981        }
2982        check_chunk(top);
2983        return 0;
2984      }
2985
2986      else
2987      {
2988        /* Success. Adjust top accordingly. */
2989        set_head(top, (top_size - extra) | PREV_INUSE);
2990        sbrked_mem -= extra;
2991        check_chunk(top);
2992        return 1;
2993      }
2994    }
2995  }
2996}
2997
2998
2999
3000/*
3001  malloc_usable_size:
3002
3003    This routine tells you how many bytes you can actually use in an
3004    allocated chunk, which may be more than you requested (although
3005    often not). You can use this many bytes without worrying about
3006    overwriting other allocated objects. Not a particularly great
3007    programming practice, but still sometimes useful.
3008
3009*/
3010
3011#if __STD_C
3012size_t malloc_usable_size(Void_t* mem)
3013#else
3014size_t malloc_usable_size(mem) Void_t* mem;
3015#endif
3016{
3017  mchunkptr p;
3018  if (mem == 0)
3019    return 0;
3020  else
3021  {
3022    p = mem2chunk(mem);
3023    if(!chunk_is_mmapped(p))
3024    {
3025      if (!inuse(p)) return 0;
3026      check_inuse_chunk(p);
3027      return chunksize(p) - SIZE_SZ;
3028    }
3029    return chunksize(p) - 2*SIZE_SZ;
3030  }
3031}
3032
3033
3034
3035
3036/* Utility to update current_mallinfo for malloc_stats and mallinfo() */
3037
3038static void malloc_update_mallinfo()
3039{
3040  int i;
3041  mbinptr b;
3042  mchunkptr p;
3043#if DEBUG
3044  mchunkptr q;
3045#endif
3046
3047  INTERNAL_SIZE_T avail = chunksize(top);
3048  int   navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;
3049
3050  for (i = 1; i < NAV; ++i)
3051  {
3052    b = bin_at(i);
3053    for (p = last(b); p != b; p = p->bk)
3054    {
3055#if DEBUG
3056      check_free_chunk(p);
3057      for (q = next_chunk(p);
3058           q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
3059           q = next_chunk(q))
3060        check_inuse_chunk(q);
3061#endif
3062      avail += chunksize(p);
3063      navail++;
3064    }
3065  }
3066
3067  current_mallinfo.ordblks = navail;
3068  current_mallinfo.uordblks = sbrked_mem - avail;
3069  current_mallinfo.fordblks = avail;
3070  current_mallinfo.hblks = n_mmaps;
3071  current_mallinfo.hblkhd = mmapped_mem;
3072  current_mallinfo.keepcost = chunksize(top);
3073
3074}
3075
3076
3077
3078/*
3079
3080  malloc_stats:
3081
3082    Prints on stderr the amount of space obtain from the system (both
3083    via sbrk and mmap), the maximum amount (which may be more than
3084    current if malloc_trim and/or munmap got called), the maximum
3085    number of simultaneous mmap regions used, and the current number
3086    of bytes allocated via malloc (or realloc, etc) but not yet
3087    freed. (Note that this is the number of bytes allocated, not the
3088    number requested. It will be larger than the number requested
3089    because of alignment and bookkeeping overhead.)
3090
3091*/
3092
3093void malloc_stats()
3094{
3095  malloc_update_mallinfo();
3096  fprintf(stderr, "max system bytes = %10u\n",
3097          (unsigned int)(max_total_mem));
3098  fprintf(stderr, "system bytes     = %10u\n",
3099          (unsigned int)(sbrked_mem + mmapped_mem));
3100  fprintf(stderr, "in use bytes     = %10u\n",
3101          (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
3102#if HAVE_MMAP
3103  fprintf(stderr, "max mmap regions = %10u\n",
3104          (unsigned int)max_n_mmaps);
3105#endif
3106}
3107
3108/*
3109  mallinfo returns a copy of updated current mallinfo.
3110*/
3111
3112struct mallinfo mALLINFo()
3113{
3114  malloc_update_mallinfo();
3115  return current_mallinfo;
3116}
3117
3118
3119
3120
3121/*
3122  mallopt:
3123
3124    mallopt is the general SVID/XPG interface to tunable parameters.
3125    The format is to provide a (parameter-number, parameter-value) pair.
3126    mallopt then sets the corresponding parameter to the argument
3127    value if it can (i.e., so long as the value is meaningful),
3128    and returns 1 if successful else 0.
3129
3130    See descriptions of tunable parameters above.
3131
3132*/
3133
3134#if __STD_C
3135int mALLOPt(int param_number, int value)
3136#else
3137int mALLOPt(param_number, value) int param_number; int value;
3138#endif
3139{
3140  switch(param_number)
3141  {
3142    case M_TRIM_THRESHOLD:
3143      trim_threshold = value; return 1;
3144    case M_TOP_PAD:
3145      top_pad = value; return 1;
3146    case M_MMAP_THRESHOLD:
3147      mmap_threshold = value; return 1;
3148    case M_MMAP_MAX:
3149#if HAVE_MMAP
3150      n_mmaps_max = value; return 1;
3151#else
3152      if (value != 0) return 0; else  n_mmaps_max = value; return 1;
3153#endif
3154
3155    default:
3156      return 0;
3157  }
3158}
3159
3160/*
3161
3162History:
3163
3164    V2.6.6 Sun Dec  5 07:42:19 1999  Doug Lea  (dl at gee)
3165      * return null for negative arguments
3166      * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com>
3167         * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
3168          (e.g. WIN32 platforms)
3169         * Cleanup up header file inclusion for WIN32 platforms
3170         * Cleanup code to avoid Microsoft Visual C++ compiler complaints
3171         * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
3172           memory allocation routines
3173         * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
3174         * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
3175           usage of 'assert' in non-WIN32 code
3176         * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
3177           avoid infinite loop
3178      * Always call 'fREe()' rather than 'free()'
3179
3180    V2.6.5 Wed Jun 17 15:57:31 1998  Doug Lea  (dl at gee)
3181      * Fixed ordering problem with boundary-stamping
3182
3183    V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
3184      * Added pvalloc, as recommended by H.J. Liu
3185      * Added 64bit pointer support mainly from Wolfram Gloger
3186      * Added anonymously donated WIN32 sbrk emulation
3187      * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
3188      * malloc_extend_top: fix mask error that caused wastage after
3189        foreign sbrks
3190      * Add linux mremap support code from HJ Liu
3191
3192    V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
3193      * Integrated most documentation with the code.
3194      * Add support for mmap, with help from
3195        Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
3196      * Use last_remainder in more cases.
3197      * Pack bins using idea from  colin@nyx10.cs.du.edu
3198      * Use ordered bins instead of best-fit threshhold
3199      * Eliminate block-local decls to simplify tracing and debugging.
3200      * Support another case of realloc via move into top
3201      * Fix error occuring when initial sbrk_base not word-aligned.
3202      * Rely on page size for units instead of SBRK_UNIT to
3203        avoid surprises about sbrk alignment conventions.
3204      * Add mallinfo, mallopt. Thanks to Raymond Nijssen
3205        (raymond@es.ele.tue.nl) for the suggestion.
3206      * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
3207      * More precautions for cases where other routines call sbrk,
3208        courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
3209      * Added macros etc., allowing use in linux libc from
3210        H.J. Lu (hjl@gnu.ai.mit.edu)
3211      * Inverted this history list
3212
3213    V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
3214      * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
3215      * Removed all preallocation code since under current scheme
3216        the work required to undo bad preallocations exceeds
3217        the work saved in good cases for most test programs.
3218      * No longer use return list or unconsolidated bins since
3219        no scheme using them consistently outperforms those that don't
3220        given above changes.
3221      * Use best fit for very large chunks to prevent some worst-cases.
3222      * Added some support for debugging
3223
3224    V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
3225      * Removed footers when chunks are in use. Thanks to
3226        Paul Wilson (wilson@cs.texas.edu) for the suggestion.
3227
3228    V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
3229      * Added malloc_trim, with help from Wolfram Gloger
3230        (wmglo@Dent.MED.Uni-Muenchen.DE).
3231
3232    V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)
3233
3234    V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
3235      * realloc: try to expand in both directions
3236      * malloc: swap order of clean-bin strategy;
3237      * realloc: only conditionally expand backwards
3238      * Try not to scavenge used bins
3239      * Use bin counts as a guide to preallocation
3240      * Occasionally bin return list chunks in first scan
3241      * Add a few optimizations from colin@nyx10.cs.du.edu
3242
3243    V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
3244      * faster bin computation & slightly different binning
3245      * merged all consolidations to one part of malloc proper
3246         (eliminating old malloc_find_space & malloc_clean_bin)
3247      * Scan 2 returns chunks (not just 1)
3248      * Propagate failure in realloc if malloc returns 0
3249      * Add stuff to allow compilation on non-ANSI compilers
3250          from kpv@research.att.com
3251
3252    V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
3253      * removed potential for odd address access in prev_chunk
3254      * removed dependency on getpagesize.h
3255      * misc cosmetics and a bit more internal documentation
3256      * anticosmetics: mangled names in macros to evade debugger strangeness
3257      * tested on sparc, hp-700, dec-mips, rs6000
3258          with gcc & native cc (hp, dec only) allowing
3259          Detlefs & Zorn comparison study (in SIGPLAN Notices.)
3260
3261    Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
3262      * Based loosely on libg++-1.2X malloc. (It retains some of the overall
3263         structure of old version,  but most details differ.)
3264
3265*/
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