## modules/up/src/Core/gnu/malloc.h

/* [<][>][^][v][top][bottom][index][help] */

## FUNCTIONS

This source file includes following functions.

1. MALLOC_ZERO
2. MALLOC_COPY
3. MALLOC_ZERO
4. MALLOC_COPY

       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 2.6.5  Wed Jun 17 15:55:16 1998  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    Note: This version differs from 2.6.4 only by correcting a
      15          statement ordering error that could cause failures only
      16          when calls to this malloc are interposed with calls to
      17          other memory allocators.
      18
      19 * Why use this malloc?
      20
      21   This is not the fastest, most space-conserving, most portable, or
      22   most tunable malloc ever written. However it is among the fastest
      23   while also being among the most space-conserving, portable and tunable.
      24   Consistent balance across these factors results in a good general-purpose
      25   allocator. For a high-level description, see
      26      http://g.oswego.edu/dl/html/malloc.html
      27
      28 * Synopsis of public routines
      29
      30   (Much fuller descriptions are contained in the program documentation below.)
      31
      32   malloc(size_t n);
      33      Return a pointer to a newly allocated chunk of at least n bytes, or null
      34      if no space is available.
      35   free(Void_t* p);
      36      Release the chunk of memory pointed to by p, or no effect if p is null.
      37   realloc(Void_t* p, size_t n);
      38      Return a pointer to a chunk of size n that contains the same data
      39      as does chunk p up to the minimum of (n, p's size) bytes, or null
      40      if no space is available. The returned pointer may or may not be
      41      the same as p. If p is null, equivalent to malloc.  Unless the
      42      #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
      43      size argument of zero (re)allocates a minimum-sized chunk.
      44   memalign(size_t alignment, size_t n);
      45      Return a pointer to a newly allocated chunk of n bytes, aligned
      46      in accord with the alignment argument, which must be a power of
      47      two.
      48   valloc(size_t n);
      49      Equivalent to memalign(pagesize, n), where pagesize is the page
      50      size of the system (or as near to this as can be figured out from
      51      all the includes/defines below.)
      52   pvalloc(size_t n);
      53      Equivalent to valloc(minimum-page-that-holds(n)), that is,
      54      round up n to nearest pagesize.
      55   calloc(size_t unit, size_t quantity);
      56      Returns a pointer to quantity * unit bytes, with all locations
      57      set to zero.
      58   cfree(Void_t* p);
      59      Equivalent to free(p).
      60   malloc_trim(size_t pad);
      61      Release all but pad bytes of freed top-most memory back
      62      to the system. Return 1 if successful, else 0.
      63   malloc_usable_size(Void_t* p);
      64      Report the number usable allocated bytes associated with allocated
      65      chunk p. This may or may not report more bytes than were requested,
      66      due to alignment and minimum size constraints.
      67   malloc_stats();
      68      Prints brief summary statistics on stderr.
      69   mallinfo()
      70      Returns (by copy) a struct containing various summary statistics.
      71   mallopt(int parameter_number, int parameter_value)
      72      Changes one of the tunable parameters described below. Returns
      73      1 if successful in changing the parameter, else 0.
      74
      75 * Vital statistics:
      76
      77   Alignment:                            8-byte
      78        8 byte alignment is currently hardwired into the design.  This
      79        seems to suffice for all current machines and C compilers.
      80
      81   Assumed pointer representation:       4 or 8 bytes
      82        Code for 8-byte pointers is untested by me but has worked
      83        reliably by Wolfram Gloger, who contributed most of the
      84        changes supporting this.
      85
      86   Assumed size_t  representation:       4 or 8 bytes
      87        Note that size_t is allowed to be 4 bytes even if pointers are 8.
      88
      89   Minimum overhead per allocated chunk: 4 or 8 bytes
      90        Each malloced chunk has a hidden overhead of 4 bytes holding size
      91        and status information.
      92
      93   Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
      94                           8-byte ptrs:  24/32 bytes (including, 4/8 overhead)
      95
      96        When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
      97        ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
      98        needed; 4 (8) for a trailing size field
      99        and 8 (16) bytes for free list pointers. Thus, the minimum
     100        allocatable size is 16/24/32 bytes.
     101
     102        Even a request for zero bytes (i.e., malloc(0)) returns a
     103        pointer to something of the minimum allocatable size.
     104
     105   Maximum allocated size: 4-byte size_t: 2^31 -  8 bytes
     106                           8-byte size_t: 2^63 - 16 bytes
     107
     108        It is assumed that (possibly signed) size_t bit values suffice to
     109        represent chunk sizes. `Possibly signed' is due to the fact
     110        that `size_t' may be defined on a system as either a signed or
     111        an unsigned type. To be conservative, values that would appear
     112        as negative numbers are avoided.
     113        Requests for sizes with a negative sign bit will return a
     114        minimum-sized chunk.
     115
     116   Maximum overhead wastage per allocated chunk: normally 15 bytes
     117
     118        Alignnment demands, plus the minimum allocatable size restriction
     119        make the normal worst-case wastage 15 bytes (i.e., up to 15
     120        more bytes will be allocated than were requested in malloc), with
     121        two exceptions:
     122          1. Because requests for zero bytes allocate non-zero space,
     123             the worst case wastage for a request of zero bytes is 24 bytes.
     124          2. For requests >= mmap_threshold that are serviced via
     125             mmap(), the worst case wastage is 8 bytes plus the remainder
     126             from a system page (the minimal mmap unit); typically 4096 bytes.
     127
     128 * Limitations
     129
     130     Here are some features that are NOT currently supported
     131
     132     * No user-definable hooks for callbacks and the like.
     133     * No automated mechanism for fully checking that all accesses
     134       to malloced memory stay within their bounds.
     135     * No support for compaction.
     136
     137 * Synopsis of compile-time options:
     138
     139     People have reported using previous versions of this malloc on all
     140     versions of Unix, sometimes by tweaking some of the defines
     141     below. It has been tested most extensively on Solaris and
     142     Linux. It is also reported to work on WIN32 platforms.
     143     People have also reported adapting this malloc for use in
     144     stand-alone embedded systems.
     145
     146     The implementation is in straight, hand-tuned ANSI C.  Among other
     147     consequences, it uses a lot of macros.  Because of this, to be at
     148     all usable, this code should be compiled using an optimizing compiler
     149     (for example gcc -O2) that can simplify expressions and control
     150     paths.
     151
     152   __STD_C                  (default: derived from C compiler defines)
     153      Nonzero if using ANSI-standard C compiler, a C++ compiler, or
     154      a C compiler sufficiently close to ANSI to get away with it.
     155   DEBUG                    (default: NOT defined)
     156      Define to enable debugging. Adds fairly extensive assertion-based
     157      checking to help track down memory errors, but noticeably slows down
     158      execution.
     159   REALLOC_ZERO_BYTES_FREES (default: NOT defined)
     160      Define this if you think that realloc(p, 0) should be equivalent
     161      to free(p). Otherwise, since malloc returns a unique pointer for
     162      malloc(0), so does realloc(p, 0).
     163   HAVE_MEMCPY               (default: defined)
     164      Define if you are not otherwise using ANSI STD C, but still
     165      have memcpy and memset in your C library and want to use them.
     166      Otherwise, simple internal versions are supplied.
     167   USE_MEMCPY               (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
     168      Define as 1 if you want the C library versions of memset and
     169      memcpy called in realloc and calloc (otherwise macro versions are used).
     170      At least on some platforms, the simple macro versions usually
     171      outperform libc versions.
     172   HAVE_MMAP                 (default: defined as 1)
     173      Define to non-zero to optionally make malloc() use mmap() to
     174      allocate very large blocks.
     175   HAVE_MREMAP                 (default: defined as 0 unless Linux libc set)
     176      Define to non-zero to optionally make realloc() use mremap() to
     177      reallocate very large blocks.
     178   malloc_getpagesize        (default: derived from system #includes)
     179      Either a constant or routine call returning the system page size.
     180   HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
     181      Optionally define if you are on a system with a /usr/include/malloc.h
     182      that declares struct mallinfo. It is not at all necessary to
     183      define this even if you do, but will ensure consistency.
     184   INTERNAL_SIZE_T           (default: size_t)
     185      Define to a 32-bit type (probably `unsigned int') if you are on a
     186      64-bit machine, yet do not want or need to allow malloc requests of
     187      greater than 2^31 to be handled. This saves space, especially for
     188      very small chunks.
     189   INTERNAL_LINUX_C_LIB      (default: NOT defined)
     190      Defined only when compiled as part of Linux libc.
     191      Also note that there is some odd internal name-mangling via defines
     192      (for example, internally, `malloc' is named `mALLOc') needed
     193      when compiling in this case. These look funny but don't otherwise
     194      affect anything.
     195   WIN32                     (default: undefined)
     196      Define this on MS win (95, nt) platforms to compile in sbrk emulation.
     197   LACKS_UNISTD_H            (default: undefined)
     198      Define this if your system does not have a <unistd.h>.
     199   MORECORE                  (default: sbrk)
     200      The name of the routine to call to obtain more memory from the system.
     201   MORECORE_FAILURE          (default: -1)
     202      The value returned upon failure of MORECORE.
     203   MORECORE_CLEARS           (default 1)
     204      True (1) if the routine mapped to MORECORE zeroes out memory (which
     205      holds for sbrk).
     206   DEFAULT_TRIM_THRESHOLD
     207   DEFAULT_TOP_PAD
     208   DEFAULT_MMAP_THRESHOLD
     209   DEFAULT_MMAP_MAX
     210      Default values of tunable parameters (described in detail below)
     211      controlling interaction with host system routines (sbrk, mmap, etc).
     212      These values may also be changed dynamically via mallopt(). The
     213      preset defaults are those that give best performance for typical
     214      programs/systems.
     215
     216
     217 */
     218
     219
     220
     221
     222 /* Preliminaries */
     223
     224 #ifndef __STD_C
     225 #ifdef __STDC__
     226 #define __STD_C     1
     227 #else
     228 #if __cplusplus
     229 #define __STD_C     1
     230 #else
     231 #define __STD_C     0
     232 #endif /*__cplusplus*/
     233 #endif /*__STDC__*/
     234 #endif /*__STD_C*/
     235
     236 #ifndef Void_t
     237 #if __STD_C
     238 #define Void_t      void
     239 #else
     240 #define Void_t      char
     241 #endif
     242 #endif /*Void_t*/
     243
     244 #if __STD_C
     245 #include <stddef.h>   /* for size_t */
     246 #else
     247 #include <sys/types.h>
     248 #endif
     249
     250 #ifdef __cplusplus
     251 extern "C" {
     252 #endif
     253
     254 #include <stdio.h>    /* needed for malloc_stats */
     255
     256
     257 /*
     258   Compile-time options
     259 */
     260
     261
     262 /*
     263     Debugging:
     264
     265     Because freed chunks may be overwritten with link fields, this
     266     malloc will often die when freed memory is overwritten by user
     267     programs.  This can be very effective (albeit in an annoying way)
     268     in helping track down dangling pointers.
     269
     270     If you compile with -DDEBUG, a number of assertion checks are
     271     enabled that will catch more memory errors. You probably won't be
     272     able to make much sense of the actual assertion errors, but they
     273     should help you locate incorrectly overwritten memory.  The
     274     checking is fairly extensive, and will slow down execution
     275     noticeably. Calling malloc_stats or mallinfo with DEBUG set will
     276     attempt to check every non-mmapped allocated and free chunk in the
     277     course of computing the summmaries. (By nature, mmapped regions
     278     cannot be checked very much automatically.)
     279
     280     Setting DEBUG may also be helpful if you are trying to modify
     281     this code. The assertions in the check routines spell out in more
     282     detail the assumptions and invariants underlying the algorithms.
     283
     284 */
     285
     286 #if DEBUG
     287 #include <assert.h>
     288 #else
     289 #define assert(x) ((void)0)
     290 #endif
     291
     292
     293 /*
     294   INTERNAL_SIZE_T is the word-size used for internal bookkeeping
     295   of chunk sizes. On a 64-bit machine, you can reduce malloc
     296   overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
     297   at the expense of not being able to handle requests greater than
     298   2^31. This limitation is hardly ever a concern; you are encouraged
     299   to set this. However, the default version is the same as size_t.
     300 */
     301
     302 #ifndef INTERNAL_SIZE_T
     303 #define INTERNAL_SIZE_T size_t
     304 #endif
     305
     306 /*
     307   REALLOC_ZERO_BYTES_FREES should be set if a call to
     308   realloc with zero bytes should be the same as a call to free.
     309   Some people think it should. Otherwise, since this malloc
     310   returns a unique pointer for malloc(0), so does realloc(p, 0).
     311 */
     312
     313
     314 /*   #define REALLOC_ZERO_BYTES_FREES */
     315
     316
     317 /*
     318   WIN32 causes an emulation of sbrk to be compiled in
     319   mmap-based options are not currently supported in WIN32.
     320 */
     321
     322 /* #define WIN32 */
     323 #ifdef WIN32
     324 #define MORECORE wsbrk
     325 #define HAVE_MMAP 0
     326 #endif
     327
     328
     329 /*
     330   HAVE_MEMCPY should be defined if you are not otherwise using
     331   ANSI STD C, but still have memcpy and memset in your C library
     332   and want to use them in calloc and realloc. Otherwise simple
     333   macro versions are defined here.
     334
     335   USE_MEMCPY should be defined as 1 if you actually want to
     336   have memset and memcpy called. People report that the macro
     337   versions are often enough faster than libc versions on many
     338   systems that it is better to use them.
     339
     340 */
     341
     342 #define HAVE_MEMCPY
     343
     344 #ifndef USE_MEMCPY
     345 #ifdef HAVE_MEMCPY
     346 #define USE_MEMCPY 1
     347 #else
     348 #define USE_MEMCPY 0
     349 #endif
     350 #endif
     351
     352 #if (__STD_C || defined(HAVE_MEMCPY))
     353
     354 #if __STD_C
     355 void* memset(void*, int, size_t);
     356 void* memcpy(void*, const void*, size_t);
     357 #else
     358 Void_t* memset();
     359 Void_t* memcpy();
     360 #endif
     361 #endif
     362
     363 #if USE_MEMCPY
     364
     365 /* The following macros are only invoked with (2n+1)-multiples of
     366    INTERNAL_SIZE_T units, with a positive integer n. This is exploited
     367    for fast inline execution when n is small. */
     368
     369 #define MALLOC_ZERO(charp, nbytes)                                            \
         /* [<][>][^][v][top][bottom][index][help] */
     370 do {                                                                          \
     371   INTERNAL_SIZE_T mzsz = (nbytes);                                            \
     372   if(mzsz <= 9*sizeof(mzsz)) {                                                \
     373     INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
     374     if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
     375                                      *mz++ = 0;                               \
     376       if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
     377                                      *mz++ = 0;                               \
     378         if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
     379                                      *mz++ = 0; }}}                           \
     380                                      *mz++ = 0;                               \
     381                                      *mz++ = 0;                               \
     382                                      *mz   = 0;                               \
     383   } else memset((charp), 0, mzsz);                                            \
     384 } while(0)
     385
     386 #define MALLOC_COPY(dest,src,nbytes)                                          \
         /* [<][>][^][v][top][bottom][index][help] */
     387 do {                                                                          \
     388   INTERNAL_SIZE_T mcsz = (nbytes);                                            \
     389   if(mcsz <= 9*sizeof(mcsz)) {                                                \
     390     INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
     391     INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
     392     if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
     393                                      *mcdst++ = *mcsrc++;                     \
     394       if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
     395                                      *mcdst++ = *mcsrc++;                     \
     396         if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
     397                                      *mcdst++ = *mcsrc++; }}}                 \
     398                                      *mcdst++ = *mcsrc++;                     \
     399                                      *mcdst++ = *mcsrc++;                     \
     400                                      *mcdst   = *mcsrc  ;                     \
     401   } else memcpy(dest, src, mcsz);                                             \
     402 } while(0)
     403
     404 #else /* !USE_MEMCPY */
     405
     406 /* Use Duff's device for good zeroing/copying performance. */
     407
     408 #define MALLOC_ZERO(charp, nbytes)                                            \
         /* [<][>][^][v][top][bottom][index][help] */
     409 do {                                                                          \
     410   INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
     411   long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
     412   if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
     413   switch (mctmp) {                                                            \
     414     case 0: for(;;) { *mzp++ = 0;                                             \
     415     case 7:           *mzp++ = 0;                                             \
     416     case 6:           *mzp++ = 0;                                             \
     417     case 5:           *mzp++ = 0;                                             \
     418     case 4:           *mzp++ = 0;                                             \
     419     case 3:           *mzp++ = 0;                                             \
     420     case 2:           *mzp++ = 0;                                             \
     421     case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
     422   }                                                                           \
     423 } while(0)
     424
     425 #define MALLOC_COPY(dest,src,nbytes)                                          \
         /* [<][>][^][v][top][bottom][index][help] */
     426 do {                                                                          \
     427   INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
     428   INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
     429   long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
     430   if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
     431   switch (mctmp) {                                                            \
     432     case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
     433     case 7:           *mcdst++ = *mcsrc++;                                    \
     434     case 6:           *mcdst++ = *mcsrc++;                                    \
     435     case 5:           *mcdst++ = *mcsrc++;                                    \
     436     case 4:           *mcdst++ = *mcsrc++;                                    \
     437     case 3:           *mcdst++ = *mcsrc++;                                    \
     438     case 2:           *mcdst++ = *mcsrc++;                                    \
     439     case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
     440   }                                                                           \
     441 } while(0)
     442
     443 #endif
     444
     445
     446 /*
     447   Define HAVE_MMAP to optionally make malloc() use mmap() to
     448   allocate very large blocks.  These will be returned to the
     449   operating system immediately after a free().
     450 */
     451
     452 #ifndef HAVE_MMAP
     453 #define HAVE_MMAP 1
     454 #endif
     455
     456 /*
     457   Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
     458   large blocks.  This is currently only possible on Linux with
     459   kernel versions newer than 1.3.77.
     460 */
     461
     462 #ifndef HAVE_MREMAP
     463 #ifdef INTERNAL_LINUX_C_LIB
     464 #define HAVE_MREMAP 1
     465 #else
     466 #define HAVE_MREMAP 0
     467 #endif
     468 #endif
     469
     470 #if HAVE_MMAP
     471
     472 #include <unistd.h>
     473 #include <fcntl.h>
     474 #include <sys/mman.h>
     475
     476 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
     477 #define MAP_ANONYMOUS MAP_ANON
     478 #endif
     479
     480 #endif /* HAVE_MMAP */
     481
     482 /*
     483   Access to system page size. To the extent possible, this malloc
     484   manages memory from the system in page-size units.
     485
     486   The following mechanics for getpagesize were adapted from
     487   bsd/gnu getpagesize.h
     488 */
     489
     490 #ifndef LACKS_UNISTD_H
     491 #  include <unistd.h>
     492 #endif
     493
     494 #ifndef malloc_getpagesize
     495 #  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
     496 #    ifndef _SC_PAGE_SIZE
     497 #      define _SC_PAGE_SIZE _SC_PAGESIZE
     498 #    endif
     499 #  endif
     500 #  ifdef _SC_PAGE_SIZE
     501 #    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
     502 #  else
     503 #    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
     504        extern size_t getpagesize();
     505 #      define malloc_getpagesize getpagesize()
     506 #    else
     507 #      include <sys/param.h>
     508 #      ifdef EXEC_PAGESIZE
     509 #        define malloc_getpagesize EXEC_PAGESIZE
     510 #      else
     511 #        ifdef NBPG
     512 #          ifndef CLSIZE
     513 #            define malloc_getpagesize NBPG
     514 #          else
     515 #            define malloc_getpagesize (NBPG * CLSIZE)
     516 #          endif
     517 #        else
     518 #          ifdef NBPC
     519 #            define malloc_getpagesize NBPC
     520 #          else
     521 #            ifdef PAGESIZE
     522 #              define malloc_getpagesize PAGESIZE
     523 #            else
     524 #              define malloc_getpagesize (4096) /* just guess */
     525 #            endif
     526 #          endif
     527 #        endif
     528 #      endif
     529 #    endif
     530 #  endif
     531 #endif
     532
     533
     534
     535 /*
     536
     537   This version of malloc supports the standard SVID/XPG mallinfo
     538   routine that returns a struct containing the same kind of
     539   information you can get from malloc_stats. It should work on
     540   any SVID/XPG compliant system that has a /usr/include/malloc.h
     541   defining struct mallinfo. (If you'd like to install such a thing
     542   yourself, cut out the preliminary declarations as described above
     543   and below and save them in a malloc.h file. But there's no
     544   compelling reason to bother to do this.)
     545
     546   The main declaration needed is the mallinfo struct that is returned
     547   (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
     548   bunch of fields, most of which are not even meaningful in this
     549   version of malloc. Some of these fields are are instead filled by
     550   mallinfo() with other numbers that might possibly be of interest.
     551
     552   HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
     553   /usr/include/malloc.h file that includes a declaration of struct
     554   mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
     555   version is declared below.  These must be precisely the same for
     556   mallinfo() to work.
     557
     558 */
     559
     560 /* #define HAVE_USR_INCLUDE_MALLOC_H */
     561
     562 #if HAVE_USR_INCLUDE_MALLOC_H
     563 #include "/usr/include/malloc.h"
     564 #else
     565
     566 /* SVID2/XPG mallinfo structure */
     567
     568 struct mallinfo {
     569   int arena;    /* total space allocated from system */
     570   int ordblks;  /* number of non-inuse chunks */
     571   int smblks;   /* unused -- always zero */
     572   int hblks;    /* number of mmapped regions */
     573   int hblkhd;   /* total space in mmapped regions */
     574   int usmblks;  /* unused -- always zero */
     575   int fsmblks;  /* unused -- always zero */
     576   int uordblks; /* total allocated space */
     577   int fordblks; /* total non-inuse space */
     578   int keepcost; /* top-most, releasable (via malloc_trim) space */
     579 };
     580
     581 /* SVID2/XPG mallopt options */
     582
     583 #define M_MXFAST  1    /* UNUSED in this malloc */
     584 #define M_NLBLKS  2    /* UNUSED in this malloc */
     585 #define M_GRAIN   3    /* UNUSED in this malloc */
     586 #define M_KEEP    4    /* UNUSED in this malloc */
     587
     588 #endif
     589
     590 /* mallopt options that actually do something */
     591
     592 #define M_TRIM_THRESHOLD    -1
     593 #define M_TOP_PAD           -2
     594 #define M_MMAP_THRESHOLD    -3
     595 #define M_MMAP_MAX          -4
     596
     597
     598
     599 #ifndef DEFAULT_TRIM_THRESHOLD
     600 #define DEFAULT_TRIM_THRESHOLD (128 * 1024)
     601 #endif
     602
     603 /*
     604     M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
     605       to keep before releasing via malloc_trim in free().
     606
     607       Automatic trimming is mainly useful in long-lived programs.
     608       Because trimming via sbrk can be slow on some systems, and can
     609       sometimes be wasteful (in cases where programs immediately
     610       afterward allocate more large chunks) the value should be high
     611       enough so that your overall system performance would improve by
     612       releasing.
     613
     614       The trim threshold and the mmap control parameters (see below)
     615       can be traded off with one another. Trimming and mmapping are
     616       two different ways of releasing unused memory back to the
     617       system. Between these two, it is often possible to keep
     618       system-level demands of a long-lived program down to a bare
     619       minimum. For example, in one test suite of sessions measuring
     620       the XF86 X server on Linux, using a trim threshold of 128K and a
     621       mmap threshold of 192K led to near-minimal long term resource
     622       consumption.
     623
     624       If you are using this malloc in a long-lived program, it should
     625       pay to experiment with these values.  As a rough guide, you
     626       might set to a value close to the average size of a process
     627       (program) running on your system.  Releasing this much memory
     628       would allow such a process to run in memory.  Generally, it's
     629       worth it to tune for trimming rather tham memory mapping when a
     630       program undergoes phases where several large chunks are
     631       allocated and released in ways that can reuse each other's
     632       storage, perhaps mixed with phases where there are no such
     633       chunks at all.  And in well-behaved long-lived programs,
     634       controlling release of large blocks via trimming versus mapping
     635       is usually faster.
     636
     637       However, in most programs, these parameters serve mainly as
     638       protection against the system-level effects of carrying around
     639       massive amounts of unneeded memory. Since frequent calls to
     640       sbrk, mmap, and munmap otherwise degrade performance, the default
     641       parameters are set to relatively high values that serve only as
     642       safeguards.
     643
     644       The default trim value is high enough to cause trimming only in
     645       fairly extreme (by current memory consumption standards) cases.
     646       It must be greater than page size to have any useful effect.  To
     647       disable trimming completely, you can set to (unsigned long)(-1);
     648
     649
     650 */
     651
     652
     653 #ifndef DEFAULT_TOP_PAD
     654 #define DEFAULT_TOP_PAD        (0)
     655 #endif
     656
     657 /*
     658     M_TOP_PAD is the amount of extra `padding' space to allocate or
     659       retain whenever sbrk is called. It is used in two ways internally:
     660
     661       * When sbrk is called to extend the top of the arena to satisfy
     662         a new malloc request, this much padding is added to the sbrk
     663         request.
     664
     665       * When malloc_trim is called automatically from free(),
     666         it is used as the `pad' argument.
     667
     668       In both cases, the actual amount of padding is rounded
     669       so that the end of the arena is always a system page boundary.
     670
     671       The main reason for using padding is to avoid calling sbrk so
     672       often. Having even a small pad greatly reduces the likelihood
     673       that nearly every malloc request during program start-up (or
     674       after trimming) will invoke sbrk, which needlessly wastes
     675       time.
     676
     677       Automatic rounding-up to page-size units is normally sufficient
     678       to avoid measurable overhead, so the default is 0.  However, in
     679       systems where sbrk is relatively slow, it can pay to increase
     680       this value, at the expense of carrying around more memory than
     681       the program needs.
     682
     683 */
     684
     685
     686 #ifndef DEFAULT_MMAP_THRESHOLD
     687 #define DEFAULT_MMAP_THRESHOLD (128 * 1024)
     688 #endif
     689
     690 /*
     691
     692     M_MMAP_THRESHOLD is the request size threshold for using mmap()
     693       to service a request. Requests of at least this size that cannot
     694       be allocated using already-existing space will be serviced via mmap.
     695       (If enough normal freed space already exists it is used instead.)
     696
     697       Using mmap segregates relatively large chunks of memory so that
     698       they can be individually obtained and released from the host
     699       system. A request serviced through mmap is never reused by any
     700       other request (at least not directly; the system may just so
     701       happen to remap successive requests to the same locations).
     702
     703       Segregating space in this way has the benefit that mmapped space
     704       can ALWAYS be individually released back to the system, which
     705       helps keep the system level memory demands of a long-lived
     706       program low. Mapped memory can never become `locked' between
     707       other chunks, as can happen with normally allocated chunks, which
     708       menas that even trimming via malloc_trim would not release them.
     709
     710       However, it has the disadvantages that:
     711
     712          1. The space cannot be reclaimed, consolidated, and then
     713             used to service later requests, as happens with normal chunks.
     714          2. It can lead to more wastage because of mmap page alignment
     715             requirements
     716          3. It causes malloc performance to be more dependent on host
     717             system memory management support routines which may vary in
     718             implementation quality and may impose arbitrary
     719             limitations. Generally, servicing a request via normal
     720             malloc steps is faster than going through a system's mmap.
     721
     722       All together, these considerations should lead you to use mmap
     723       only for relatively large requests.
     724
     725
     726 */
     727
     728
     729
     730 #ifndef DEFAULT_MMAP_MAX
     731 #if HAVE_MMAP
     732 #define DEFAULT_MMAP_MAX       (64)
     733 #else
     734 #define DEFAULT_MMAP_MAX       (0)
     735 #endif
     736 #endif
     737
     738 /*
     739     M_MMAP_MAX is the maximum number of requests to simultaneously
     740       service using mmap. This parameter exists because:
     741
     742          1. Some systems have a limited number of internal tables for
     743             use by mmap.
     744          2. In most systems, overreliance on mmap can degrade overall
     745             performance.
     746          3. If a program allocates many large regions, it is probably
     747             better off using normal sbrk-based allocation routines that
     748             can reclaim and reallocate normal heap memory. Using a
     749             small value allows transition into this mode after the
     750             first few allocations.
     751
     752       Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
     753       the default value is 0, and attempts to set it to non-zero values
     754       in mallopt will fail.
     755 */
     756
     757
     758
     759
     760 /*
     761
     762   Special defines for linux libc
     763
     764   Except when compiled using these special defines for Linux libc
     765   using weak aliases, this malloc is NOT designed to work in
     766   multithreaded applications.  No semaphores or other concurrency
     767   control are provided to ensure that multiple malloc or free calls
     768   don't run at the same time, which could be disasterous. A single
     769   semaphore could be used across malloc, realloc, and free (which is
     770   essentially the effect of the linux weak alias approach). It would
     771   be hard to obtain finer granularity.
     772
     773 */
     774
     775
     776 #ifdef INTERNAL_LINUX_C_LIB
     777
     778 #if __STD_C
     779
     780 Void_t * __default_morecore_init (ptrdiff_t);
     781 Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
     782
     783 #else
     784
     785 Void_t * __default_morecore_init ();
     786 Void_t *(*__morecore)() = __default_morecore_init;
     787
     788 #endif
     789
     790 #define MORECORE (*__morecore)
     791 #define MORECORE_FAILURE 0
     792 #define MORECORE_CLEARS 1
     793
     794 #else /* INTERNAL_LINUX_C_LIB */
     795 /*
     796 #if __STD_C
     797 extern Void_t*     sbrk(ptrdiff_t);
     798 #else
     799 extern Void_t*     sbrk();
     800 #endif
     801 */
     802 #ifndef MORECORE
     803 #define MORECORE sbrk
     804 #endif
     805
     806 #ifndef MORECORE_FAILURE
     807 #define MORECORE_FAILURE -1
     808 #endif
     809
     810 #ifndef MORECORE_CLEARS
     811 #define MORECORE_CLEARS 1
     812 #endif
     813
     814 #endif /* INTERNAL_LINUX_C_LIB */
     815
     816 #if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)
     817
     818 #define cALLOc          __libc_calloc
     819 #define fREe            __libc_free
     820 #define mALLOc          __libc_malloc
     821 #define mEMALIGn        __libc_memalign
     822 #define rEALLOc         __libc_realloc
     823 #define vALLOc          __libc_valloc
     824 #define pvALLOc         __libc_pvalloc
     825 #define mALLINFo        __libc_mallinfo
     826 #define mALLOPt         __libc_mallopt
     827
     828 #pragma weak calloc = __libc_calloc
     829 #pragma weak free = __libc_free
     830 #pragma weak cfree = __libc_free
     831 #pragma weak malloc = __libc_malloc
     832 #pragma weak memalign = __libc_memalign
     833 #pragma weak realloc = __libc_realloc
     834 #pragma weak valloc = __libc_valloc
     835 #pragma weak pvalloc = __libc_pvalloc
     836 #pragma weak mallinfo = __libc_mallinfo
     837 #pragma weak mallopt = __libc_mallopt
     838
     839 #else
     840
     841
     842 #define cALLOc          calloc
     843 #define fREe            free
     844 #define mALLOc          malloc
     845 #define mEMALIGn        memalign
     846 #define rEALLOc         realloc
     847 #define vALLOc          valloc
     848 #define pvALLOc         pvalloc
     849 #define mALLINFo        mallinfo
     850 #define mALLOPt         mallopt
     851
     852 #endif
     853
     854 /* Public routines */
     855
     856 #if __STD_C
     857
     858 Void_t* mALLOc(size_t);
     859 void    fREe(Void_t*);
     860 Void_t* rEALLOc(Void_t*, size_t);
     861 Void_t* mEMALIGn(size_t, size_t);
     862 Void_t* vALLOc(size_t);
     863 Void_t* pvALLOc(size_t);
     864 Void_t* cALLOc(size_t, size_t);
     865 void    cfree(Void_t*);
     866 int     malloc_trim(size_t);
     867 size_t  malloc_usable_size(Void_t*);
     868 void    malloc_stats();
     869 int     mALLOPt(int, int);
     870 struct mallinfo mALLINFo(void);
     871 #else
     872 Void_t* mALLOc();
     873 void    fREe();
     874 Void_t* rEALLOc();
     875 Void_t* mEMALIGn();
     876 Void_t* vALLOc();
     877 Void_t* pvALLOc();
     878 Void_t* cALLOc();
     879 void    cfree();
     880 int     malloc_trim();
     881 size_t  malloc_usable_size();
     882 void    malloc_stats();
     883 int     mALLOPt();
     884 struct mallinfo mALLINFo();
     885 #endif
     886
     887
     888 #ifdef __cplusplus
     889 };  /* end of extern "C" */
     890 #endif
     891
     892 /* ---------- To make a malloc.h, end cutting here ------------ */

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