source: vbox/trunk/src/libs/xpcom18a4/xpcom/build/malloc.c@ 59704

#define USE_MALLOC_LOCK
#define DEFAULT_TRIM_THRESHOLD (256 * 1024)

/* ---------- To make a malloc.h, start cutting here ------------ */

/*
  ****************************************************************
  * THIS IS A PRERELEASE. It has not yet been tested adequately. *
  * If you use it, please send back comments, suggestions,       *
  * performance reports, etc.                                    *
  ****************************************************************
*/

/*
  A version (aka dlmalloc) of malloc/free/realloc written by Doug
  Lea and released to the public domain.  Use this code without
  permission or acknowledgement in any way you wish.  Send questions,
  comments, complaints, performance data, etc to [email protected]

* VERSION 2.7.0pre7 Wed Jan 10 13:33:01 2001  Doug Lea  (dl at gee)

   Note: There may be an updated version of this malloc obtainable at
           ftp://gee.cs.oswego.edu/pub/misc/malloc.c
         Check before installing!

* Quickstart

  This library is all in one file to simplify the most common usage:
  ftp it, compile it (-O), and link it into another program. All
  of the compile-time options default to reasonable values for use on
  most unix platforms. Compile -DWIN32 for reasonable defaults on windows.
  You might later want to step through various compile options.

* Why use this malloc?

  This is not the fastest, most space-conserving, most portable, or
  most tunable malloc ever written. However it is among the fastest
  while also being among the most space-conserving, portable and tunable.
  Consistent balance across these factors results in a good general-purpose
  allocator for malloc-intensive programs.

  The main properties of the algorithms are:
  * For large (>= 512 bytes) requests, it is a pure best-fit allocator,
    with ties normally decided via FIFO (i.e. least recently used).
  * For small (<= 64 bytes by default) requests, it is a caching
    allocator, that maintains pools of quickly recycled chunks.
  * In between, and for combinations of large and small requests, it does
    the best it can trying to meet both goals at once.

  Compared to 2.6.X versions, this version is generally faster,
  especially for programs that allocate and free many small chunks.

  For a longer but slightly out of date high-level description, see
     http://gee.cs.oswego.edu/dl/html/malloc.html

  You may already by default be using a c library containing a malloc
  that is somehow based on some version of this malloc (for example in
  linux). You might still want to use the one in this file in order to
  customize settings or to avoid overheads associated with library
  versions.

* Synopsis of public routines

  (Much fuller descriptions are contained in the program documentation below.)

  malloc(size_t n);
     Return a pointer to a newly allocated chunk of at least n bytes, or null
     if no space is available.
  free(Void_t* p);
     Release the chunk of memory pointed to by p, or no effect if p is null.
  realloc(Void_t* p, size_t n);
     Return a pointer to a chunk of size n that contains the same data
     as does chunk p up to the minimum of (n, p's size) bytes, or null
     if no space is available. The returned pointer may or may not be
     the same as p. If p is null, equivalent to malloc.  Unless the
     #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
     size argument of zero (re)allocates a minimum-sized chunk.
  memalign(size_t alignment, size_t n);
     Return a pointer to a newly allocated chunk of n bytes, aligned
     in accord with the alignment argument, which must be a power of
     two.
  valloc(size_t n);
     Equivalent to memalign(pagesize, n), where pagesize is the page
     size of the system (or as near to this as can be figured out from
     all the includes/defines below.)
  pvalloc(size_t n);
     Equivalent to valloc(minimum-page-that-holds(n)), that is,
     round up n to nearest pagesize.
  calloc(size_t unit, size_t quantity);
     Returns a pointer to quantity * unit bytes, with all locations
     set to zero.
  cfree(Void_t* p);
     Equivalent to free(p).
  malloc_trim(size_t pad);
     Release all but pad bytes of freed top-most memory back
     to the system. Return 1 if successful, else 0.
  malloc_usable_size(Void_t* p);
     Report the number usable allocated bytes associated with allocated
     chunk p. This may or may not report more bytes than were requested,
     due to alignment and minimum size constraints.
  malloc_stats();
     Prints brief summary statistics on stderr.
  mallinfo()
     Returns (by copy) a struct containing various summary statistics.
  mallopt(int parameter_number, int parameter_value)
     Changes one of the tunable parameters described below. Returns
     1 if successful in changing the parameter, else 0.

* Vital statistics:

  Assumed pointer representation:       4 or 8 bytes
       (Thanks to Wolfram Gloger for contributing most of the
       changes supporting dual 4/8.)

  Assumed size_t  representation:       4 or 8 bytes 
       Note that size_t is allowed to be 4 bytes even if pointers are 8.
       You can adjust this by defining INTERNAL_SIZE_T

  Alignment:                            2 * sizeof(size_t) 
       (i.e., 8 byte alignment with 4byte size_t). This suffices for
       nearly all current machines and C compilers. However, you can
       define MALLOC_ALIGNMENT to be wider than this if necessary.

  Minimum overhead per allocated chunk: 4 or 8 bytes
       Each malloced chunk has a hidden word of overhead holding size
       and status information.

  Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
                          8-byte ptrs:  24/32 bytes (including, 4/8 overhead)

       When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
       ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
       needed; 4 (8) for a trailing size field and 8 (16) bytes for
       free list pointers. Thus, the minimum allocatable size is
       16/24/32 bytes.

       Even a request for zero bytes (i.e., malloc(0)) returns a
       pointer to something of the minimum allocatable size.

       The maximum overhead wastage (i.e., number of extra bytes
       allocated than were requested in malloc) is less than or equal
       to the minimum size, except for requests >= mmap_threshold that
       are serviced via mmap(), where the worst case wastage is 2 *
       sizeof(size_t) bytes plus the remainder from a system page (the
       minimal mmap unit); typically 4096 bytes.

  Maximum allocated size: 4-byte size_t: 2^31 minus about two pages
                          8-byte size_t: 2^63 minus about two pages

       It is assumed that (possibly signed) size_t values suffice
       to represent chunk sizes. `Possibly signed' is due to the fact
       that `size_t' may be defined on a system as either a signed or
       an unsigned type. The ISO C standard says that it must be
       unsigned, but a few systems are known not to adhere to this.
       Additionally, even when size_t is unsigned, sbrk (which is by
       default used to obtain memory from system) accepts signed
       arguments, and may not be able to handle size_t-wide arguments
       with negative sign bit.  To be conservative, values that would
       appear as negative after accounting for overhead and alignment
       are rejected.

       Requests for sizes outside this range will perform an optional
       failure action and then return null. (Requests may also
       also fail because a system is out of memory.)

  Thread-safety: NOT thread-safe unless USE_MALLOC_LOCK defined

       When USE_MALLOC_LOCK is defined, wrappers are created to
       surround every public call with either a pthread mutex or
       a win32 critical section (depending on WIN32). This is not
       especially fast, and can be a major bottleneck in programs with
       many threads. It is designed only to provide minimal protection
       in concurrent environments, and to provide a basis for
       extensions.  If you are using malloc in a concurrent program,
       you would be far better off obtaining ptmalloc, which is
       derived from a version of this malloc, and is well-tuned for
       concurrent programs. (See http://www.malloc.de)

  Compliance: I believe it is compliant with the 1997 Single Unix Specification

       (See http://www.opennc.org). Probably other standards as well.

* Limitations

    Here are some features that are NOT currently supported

    * No automated mechanism for fully checking that all accesses
      to malloced memory stay within their bounds. However, there
      are several add-ons and adaptations of this or other mallocs
      available that do this.
    * No support for compaction.

* Synopsis of compile-time options:

    People have reported using previous versions of this malloc on all
    versions of Unix, sometimes by tweaking some of the defines
    below. It has been tested most extensively on Solaris and
    Linux. It is also reported to work on WIN32 platforms.
    People also report using it in stand-alone embedded systems.

    The implementation is in straight, hand-tuned ANSI C.  It is not
    at all modular. (Sorry!)  It uses a lot of macros.  To be at all
    usable, this code should be compiled using an optimizing compiler
    (for example gcc -O3) that can simplify expressions and control
    paths. (FAQ: some macros import variables as arguments rather than
    declare locals because people reported that some debuggers
    otherwise get confused.)

    OPTION                     DEFAULT VALUE

    Compilation Environment options:

    __STD_C                    derived from C compiler defines
    WIN32                      NOT defined
    HAVE_MEMCPY                defined
    USE_MEMCPY                 1 if HAVE_MEMCPY is defined
    HAVE_MMAP                  defined as 1 
    MMAP_AS_MORECORE_SIZE      (1024 * 1024) 
    HAVE_MREMAP                defined as 0 unless linux defined
    malloc_getpagesize         derived from system #includes, or 4096 if not
    HAVE_USR_INCLUDE_MALLOC_H  NOT defined
    LACKS_UNISTD_H             NOT defined unless WIN32
    LACKS_SYS_PARAM_H          NOT defined unless WIN32
    LACKS_SYS_MMAN_H           NOT defined unless WIN32

    Changing default word sizes:

    INTERNAL_SIZE_T            size_t
    MALLOC_ALIGNMENT           2 * sizeof(INTERNAL_SIZE_T)

    Configuration and functionality options:

    USE_DL_PREFIX              NOT defined
    USE_PUBLIC_MALLOC_WRAPPERS NOT defined
    USE_MALLOC_LOCK            NOT defined
    DEBUG                      NOT defined
    REALLOC_ZERO_BYTES_FREES   NOT defined
    MALLOC_FAILURE_ACTION      errno = ENOMEM, if __STD_C defined, else no-op
    TRIM_FASTBINS              0

    Options for customizing MORECORE:

    MORECORE                   sbrk
    MORECORE_CONTIGUOUS        1 

    Tuning options that are also dynamically changeable via mallopt:

    DEFAULT_MXFAST             64
    DEFAULT_TRIM_THRESHOLD     128 * 1024
    DEFAULT_TOP_PAD            0
    DEFAULT_MMAP_THRESHOLD     128 * 1024
    DEFAULT_MMAP_MAX           256

    There are several other #defined constants and macros that you
    probably don't want to touch unless you are extending or adapting malloc.

*/
#include "xpcom-private.h"




/*
  WIN32 sets up defaults for MS environment and compilers.
  Otherwise defaults are for unix.
*/

/* #define WIN32 */

#ifdef WIN32

#include <windows.h>

/* Win32 doesn't supply or need the following headers */
#define LACKS_UNISTD_H
#define LACKS_SYS_PARAM_H
#define LACKS_SYS_MMAN_H

/* Use the supplied emulation of sbrk */
#define MORECORE sbrk
#define MORECORE_CONTIGUOUS 1
#define MORECORE_FAILURE    ((void*)(-1))

/* Use the supplied emulation mmap, munmap */
#define HAVE_MMAP 1
#define MUNMAP_FAILURE  (-1)
/* These values don't really matter in windows mmap emulation */
#define MAP_PRIVATE 1
#define MAP_ANONYMOUS 2
#define PROT_READ 1
#define PROT_WRITE 2

/* Emulation functions defined at the end of this file */

/* If USE_MALLOC_LOCK, use supplied critical-section-based lock functions */
#ifdef USE_MALLOC_LOCK
static int slwait(int *sl);
static int slrelease(int *sl);
#endif

static long getpagesize(void);
static long getregionsize(void);
static void *sbrk(long size);
static void *mmap(void *ptr, long size, long prot, long type, long handle, long arg);
static long munmap(void *ptr, long size);

static void vminfo (unsigned long *free, unsigned long *reserved, unsigned long *committed);
static int cpuinfo (int whole, unsigned long *kernel, unsigned long *user);

#endif



/*
  __STD_C should be nonzero if using ANSI-standard C compiler, a C++
  compiler, or a C compiler sufficiently close to ANSI to get away
  with it.
*/

#ifndef __STD_C
#ifdef __STDC__
#define __STD_C     1
#else
#if __cplusplus
#define __STD_C     1
#else
#define __STD_C     0
#endif /*__cplusplus*/
#endif /*__STDC__*/
#endif /*__STD_C*/


/*
  Void_t* is the pointer type that malloc should say it returns
*/

#ifndef Void_t
#if (__STD_C || defined(WIN32))
#define Void_t      void
#else
#define Void_t      char
#endif
#endif /*Void_t*/

#if __STD_C
#include <stddef.h>   /* for size_t */
#else
#include <sys/types.h>
#endif

#ifdef __cplusplus
extern "C" {
#endif

/* define LACKS_UNISTD_H if your system does not have a <unistd.h>. */

/* #define  LACKS_UNISTD_H */

#ifndef LACKS_UNISTD_H
#include <unistd.h>
#endif

/* define LACKS_SYS_PARAM_H if your system does not have a <sys/param.h>. */

/* #define  LACKS_SYS_PARAM_H */


#include <stdio.h>    /* needed for malloc_stats */
#include <errno.h>    /* needed for optional MALLOC_FAILURE_ACTION */


/*
  Debugging:

  Because freed chunks may be overwritten with bookkeeping fields, this
  malloc will often die when freed memory is overwritten by user
  programs.  This can be very effective (albeit in an annoying way)
  in helping track down dangling pointers.

  If you compile with -DDEBUG, a number of assertion checks are
  enabled that will catch more memory errors. You probably won't be
  able to make much sense of the actual assertion errors, but they
  should help you locate incorrectly overwritten memory.  The
  checking is fairly extensive, and will slow down execution
  noticeably. Calling malloc_stats or mallinfo with DEBUG set will
  attempt to check every non-mmapped allocated and free chunk in the
  course of computing the summmaries. (By nature, mmapped regions
  cannot be checked very much automatically.)

  Setting DEBUG may also be helpful if you are trying to modify
  this code. The assertions in the check routines spell out in more
  detail the assumptions and invariants underlying the algorithms.

*/

#if DEBUG
#include <assert.h>
#else
#define assert(x) ((void)0)
#endif


/*
  INTERNAL_SIZE_T is the word-size used for internal bookkeeping
  of chunk sizes.

  The default version is the same as size_t.

  While not strictly necessary, it is best to define this as an
  unsigned type, even if size_t is a signed type. This may avoid some
  artificial size limitations on some systems.

  On a 64-bit machine, you may be able to reduce malloc overhead by
  defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' at the
  expense of not being able to handle more than 2^32 of malloced
  space. If this limitation is acceptable, you are encouraged to set
  this unless you are on a platform requiring 16byte alignments. In
  this case the alignment requirements turn out to negate any
  potential advantages of decreasing size_t word size.

  Note to implementors: To deal with all this, comparisons and
  difference computations among INTERNAL_SIZE_Ts should normally cast
  INTERNAL_SIZE_T's to long or unsigned long, as appropriate, being
  aware of the fact that casting an unsigned int to a wider long does not
  sign-extend. (This also makes checking for negative numbers awkward.)

*/

#ifndef INTERNAL_SIZE_T
#define INTERNAL_SIZE_T size_t
#endif

/* The corresponding word size */
#define SIZE_SZ                (sizeof(INTERNAL_SIZE_T))


/*
  MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks.
  It must be a power of two at least 2 * SIZE_SZ, even on machines
  for which smaller alignments would suffice. It may be defined as
  larger than this though. (Note however that code and data structures
  are optimized for the case of 8-byte alignment.)

*/

  /* #define MALLOC_ALIGNMENT 16 */

#ifndef MALLOC_ALIGNMENT
#define MALLOC_ALIGNMENT       (2 * SIZE_SZ)
#endif

/* The corresponding bit mask value */
#define MALLOC_ALIGN_MASK      (MALLOC_ALIGNMENT - 1)


/*
  REALLOC_ZERO_BYTES_FREES should be set if a call to
  realloc with zero bytes should be the same as a call to free.
  Some people think it should. Otherwise, since this malloc
  returns a unique pointer for malloc(0), so does realloc(p, 0).
*/

/*   #define REALLOC_ZERO_BYTES_FREES */


/*
  USE_DL_PREFIX will prefix all public routines with the string 'dl'.
  This is necessary when you only want to use this malloc in one part 
  of a program, using your regular system malloc elsewhere.
*/

/* #define USE_DL_PREFIX */


/*
  USE_MALLOC_LOCK causes wrapper functions to surround each
  callable routine with pthread mutex lock/unlock.

  USE_MALLOC_LOCK forces USE_PUBLIC_MALLOC_WRAPPERS to be defined
*/

/* #define USE_MALLOC_LOCK */


/*
  If USE_PUBLIC_MALLOC_WRAPPERS is defined, every public routine is
  actually a wrapper function that first calls MALLOC_PREACTION, then
  calls the internal routine, and follows it with
  MALLOC_POSTACTION. This is needed for locking, but you can also use
  this, without USE_MALLOC_LOCK, for purposes of interception,
  instrumentation, etc. It is a sad fact that using wrappers often
  noticeably degrades performance of malloc-intensive programs.
*/

#ifdef USE_MALLOC_LOCK
#define USE_PUBLIC_MALLOC_WRAPPERS
#else
/* #define USE_PUBLIC_MALLOC_WRAPPERS */
#endif




/*
  HAVE_MEMCPY should be defined if you are not otherwise using
  ANSI STD C, but still have memcpy and memset in your C library
  and want to use them in calloc and realloc. Otherwise simple
  macro versions are defined below.

  USE_MEMCPY should be defined as 1 if you actually want to
  have memset and memcpy called. People report that the macro
  versions are faster than libc versions on some systems.
  
  Even if USE_MEMCPY is set to 1, loops to copy/clear small chunks
  (of <= 36 bytes) are manually unrolled in realloc and calloc.
*/

#define HAVE_MEMCPY

#ifndef USE_MEMCPY
#ifdef HAVE_MEMCPY
#define USE_MEMCPY 1
#else
#define USE_MEMCPY 0
#endif
#endif


#if (__STD_C || defined(HAVE_MEMCPY))

#ifdef WIN32
  /*
    On Win32 platforms, 'memset()' and 'memcpy()' are already declared in
    'windows.h'
  */
#else
#if __STD_C
void* memset(void*, int, size_t);
void* memcpy(void*, const void*, size_t);
void* memmove(void*, const void*, size_t);
#else
Void_t* memset();
Void_t* memcpy();
Void_t* memmove();
#endif
#endif
#endif


/*
  MALLOC_FAILURE_ACTION is the action to take before "return 0" when
  malloc fails to be able to return memory, either because memory is
  exhausted or because of illegal arguments.
  
  By default, sets errno if running on STD_C platform, else does nothing.  
*/

#ifndef MALLOC_FAILURE_ACTION
#if __STD_C
#define MALLOC_FAILURE_ACTION \
   errno = ENOMEM;

#else

#define MALLOC_FAILURE_ACTION
#endif
#endif

/*
  Define HAVE_MMAP as true to optionally make malloc() use mmap() to
  allocate very large blocks.  These will be returned to the
  operating system immediately after a free(). Also, if mmap
  is available, it is used as a backup strategy in cases where
  MORECORE fails to provide space from system.

  This malloc is best tuned to work with mmap for large requests.
  If you do not have mmap, allocation of very large chunks (1MB
  or so) may be slower than you'd like.
*/

#ifndef HAVE_MMAP
#define HAVE_MMAP 1
#endif

/* 
   MMAP_AS_MORECORE_SIZE is the minimum mmap size argument to use if
   sbrk fails, and mmap is used as a backup (which is done only if
   HAVE_MMAP).  The value must be a multiple of page size.  This
   backup strategy generally applies only when systems have "holes" in
   address space, so sbrk cannot perform contiguous expansion, but
   there is still space available on system.  On systems for which
   this is known to be useful (i.e. most linux kernels), this occurs
   only when programs allocate huge amounts of memory.  Between this,
   and the fact that mmap regions tend to be limited, the size should
   be large, to avoid too many mmap calls and thus avoid running out
   of kernel resources.
*/

#ifndef MMAP_AS_MORECORE_SIZE
#define MMAP_AS_MORECORE_SIZE (1024 * 1024)
#endif



/*
  Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
  large blocks.  This is currently only possible on Linux with
  kernel versions newer than 1.3.77.
*/

#ifndef HAVE_MREMAP
#ifdef linux
#define HAVE_MREMAP 1
#else
#define HAVE_MREMAP 0
#endif

#endif /* HAVE_MMAP */


/*

  This version of malloc supports the standard SVID/XPG mallinfo
  routine that returns a struct containing usage properties and
  statistics. It should work on any SVID/XPG compliant system that has
  a /usr/include/malloc.h defining struct mallinfo. (If you'd like to
  install such a thing yourself, cut out the preliminary declarations
  as described above and below and save them in a malloc.h file. But
  there's no compelling reason to bother to do this.)

  The main declaration needed is the mallinfo struct that is returned
  (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
  bunch of field that are not even meaningful in this version of
  malloc.  These fields are are instead filled by mallinfo() with
  other numbers that might be of interest.

  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
  /usr/include/malloc.h file that includes a declaration of struct
  mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
  version is declared below.  These must be precisely the same for
  mallinfo() to work.

*/

/* #define HAVE_USR_INCLUDE_MALLOC_H */

#ifdef HAVE_USR_INCLUDE_MALLOC_H
#include "/usr/include/malloc.h"
#else

/* SVID2/XPG mallinfo structure */

struct mallinfo {
  int arena;    /* non-mmapped space allocated from system */
  int ordblks;  /* number of free chunks */
  int smblks;   /* number of fastbin blocks */
  int hblks;    /* number of mmapped regions */
  int hblkhd;   /* space in mmapped regions */
  int usmblks;  /* maximum total allocated space */
  int fsmblks;  /* space available in freed fastbin blocks */
  int uordblks; /* total allocated space */
  int fordblks; /* total free space */
  int keepcost; /* top-most, releasable (via malloc_trim) space */
};

/* SVID2/XPG mallopt options */

#define M_MXFAST  1    /* Set maximum fastbin size */
#define M_NLBLKS  2    /* UNUSED in this malloc */
#define M_GRAIN   3    /* UNUSED in this malloc */
#define M_KEEP    4    /* UNUSED in this malloc */


#endif


/* Additional mallopt options supported in this malloc */

#ifndef M_TRIM_THRESHOLD
#define M_TRIM_THRESHOLD    -1
#endif

#ifndef M_TOP_PAD
#define M_TOP_PAD           -2
#endif

#ifndef M_MMAP_THRESHOLD
#define M_MMAP_THRESHOLD    -3
#endif

#ifndef M_MMAP_MAX
#define M_MMAP_MAX          -4
#endif


/*
  MXFAST is the maximum request size used for "fastbins", special bins
  that hold returned chunks without consolidating their spaces. This
  enables future requests for chunks of the same size to be handled
  very quickly, but can increase fragmentation, and thus increase the
  overall memory footprint of a program.

  This malloc manages fastbins very conservatively yet still
  efficiently, so fragmentation is rarely a problem for values less
  than or equal to the default.  The maximum supported value of MXFAST
  is 80. You wouldn't want it any higher than this anyway.  Fastbins
  are designed especially for use with many small structs, objects or
  strings -- the default handles structs/objects/arrays with sizes up
  to 8 4byte fields, or small strings representing words, tokens,
  etc. Using fastbins for larger objects normally worsens
  fragmentation without improving speed.

  MXFAST is set in REQUEST size units. It is internally used in
  chunksize units, which adds padding and alignment.  You can reduce
  MXFAST to 0 to disable all use of fastbins.  This causes the malloc
  algorithm to be a close approximation of fifo-best-fit in all cases,
  not just for larger requests, but will generally cause it to be
  slower.

*/

#ifndef DEFAULT_MXFAST
#define DEFAULT_MXFAST     64
#endif


/*
  M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
  to keep before releasing via malloc_trim in free().

  Automatic trimming is mainly useful in long-lived programs.
  Because trimming via sbrk can be slow on some systems, and can
  sometimes be wasteful (in cases where programs immediately
  afterward allocate more large chunks) the value should be high
  enough so that your overall system performance would improve by
  releasing.

  The trim threshold and the mmap control parameters (see below)
  can be traded off with one another. Trimming and mmapping are
  two different ways of releasing unused memory back to the
  system. Between these two, it is often possible to keep
  system-level demands of a long-lived program down to a bare
  minimum. For example, in one test suite of sessions measuring
  the XF86 X server on Linux, using a trim threshold of 128K and a
  mmap threshold of 192K led to near-minimal long term resource
  consumption.

  If you are using this malloc in a long-lived program, it should
  pay to experiment with these values.  As a rough guide, you
  might set to a value close to the average size of a process
  (program) running on your system.  Releasing this much memory
  would allow such a process to run in memory.  Generally, it's
  worth it to tune for trimming rather tham memory mapping when a
  program undergoes phases where several large chunks are
  allocated and released in ways that can reuse each other's
  storage, perhaps mixed with phases where there are no such
  chunks at all.  And in well-behaved long-lived programs,
  controlling release of large blocks via trimming versus mapping
  is usually faster.

  However, in most programs, these parameters serve mainly as
  protection against the system-level effects of carrying around
  massive amounts of unneeded memory. Since frequent calls to
  sbrk, mmap, and munmap otherwise degrade performance, the default
  parameters are set to relatively high values that serve only as
  safeguards.

  The default trim value is high enough to cause trimming only in
  fairly extreme (by current memory consumption standards) cases.
  It must be greater than page size to have any useful effect.  To
  disable trimming completely, you can set to (unsigned long)(-1);

  Trim settings interact with fastbin (MXFAST) settings: Unless
  TRIM_FASTBINS is defined, automatic trimming never takes place upon
  freeing a chunk with size less than or equal to MXFAST. Trimming is
  instead delayed until subsequent freeing of larger chunks. However,
  you can still force an attempted trim by calling malloc_trim.

  Also, trimming is not generally possible in cases where
  the main arena is obtained via mmap.

*/


#ifndef DEFAULT_TRIM_THRESHOLD
#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
#endif



/*
  M_TOP_PAD is the amount of extra `padding' space to allocate or
  retain whenever sbrk is called. It is used in two ways internally:

  * When sbrk is called to extend the top of the arena to satisfy
  a new malloc request, this much padding is added to the sbrk
  request.

  * When malloc_trim is called automatically from free(),
  it is used as the `pad' argument.

  In both cases, the actual amount of padding is rounded
  so that the end of the arena is always a system page boundary.

  The main reason for using padding is to avoid calling sbrk so
  often. Having even a small pad greatly reduces the likelihood
  that nearly every malloc request during program start-up (or
  after trimming) will invoke sbrk, which needlessly wastes
  time.

  Automatic rounding-up to page-size units is normally sufficient
  to avoid measurable overhead, so the default is 0.  However, in
  systems where sbrk is relatively slow, it can pay to increase
  this value, at the expense of carrying around more memory than
  the program needs.

*/

#ifndef DEFAULT_TOP_PAD
#define DEFAULT_TOP_PAD        (0)
#endif

/*

  M_MMAP_THRESHOLD is the request size threshold for using mmap()
  to service a request. Requests of at least this size that cannot
  be allocated using already-existing space will be serviced via mmap.
  (If enough normal freed space already exists it is used instead.)

  Using mmap segregates relatively large chunks of memory so that
  they can be individually obtained and released from the host
  system. A request serviced through mmap is never reused by any
  other request (at least not directly; the system may just so
  happen to remap successive requests to the same locations).

  Segregating space in this way has the benefit that mmapped space
  can ALWAYS be individually released back to the system, which
  helps keep the system level memory demands of a long-lived
  program low. Mapped memory can never become `locked' between
  other chunks, as can happen with normally allocated chunks, which
  means that even trimming via malloc_trim would not release them.

  However, it has the disadvantages that:

   1. The space cannot be reclaimed, consolidated, and then
      used to service later requests, as happens with normal chunks.
   2. It can lead to more wastage because of mmap page alignment
      requirements
   3. It causes malloc performance to be more dependent on host
      system memory management support routines which may vary in
      implementation quality and may impose arbitrary
      limitations. Generally, servicing a request via normal
      malloc steps is faster than going through a system's mmap.

  All together, these considerations should lead you to use mmap
  only for relatively large requests.

*/


#ifndef DEFAULT_MMAP_THRESHOLD
#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
#endif

/*
  M_MMAP_MAX is the maximum number of requests to simultaneously
  service using mmap. This parameter exists because:

  1. Some systems have a limited number of internal tables for
     use by mmap.
  2. In most systems, overreliance on mmap can degrade overall
     performance.
  3. If a program allocates many large regions, it is probably
     better off using normal sbrk-based allocation routines that
     can reclaim and reallocate normal heap memory. 

  Setting to 0 disables use of mmap for servicing large requests.  If
  HAVE_MMAP is not set, the default value is 0, and attempts to set it
  to non-zero values in mallopt will fail.
*/



#ifndef DEFAULT_MMAP_MAX
#if HAVE_MMAP
#define DEFAULT_MMAP_MAX       (256)
#else
#define DEFAULT_MMAP_MAX       (0)
#endif
#endif


/*
  TRIM_FASTBINS controls whether free() of a very small chunk can
  immediately lead to trimming. Setting to true (1) can reduce memory
  footprint, but will almost always slow down (by a few percent)
  programs that use a lot of small chunks.

  Define this only if you are willing to give up some speed to more
  aggressively reduce system-level memory footprint when releasing
  memory in programs that use many small chunks.  You can get
  essentially the same effect by setting MXFAST to 0, but this can
  lead to even greater slowdowns in programs using many small chunks.
  TRIM_FASTBINS is an in-between compile-time option, that disables
  only those chunks bordering topmost memory from being placed in
  fastbins.

*/


#ifndef TRIM_FASTBINS
#define TRIM_FASTBINS  0
#endif


/*
  MORECORE-related declarations. By default, rely on sbrk
*/


#ifdef LACKS_UNISTD_H
#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
#if __STD_C
extern Void_t*     sbrk(ptrdiff_t);
#else
extern Void_t*     sbrk();
#endif
#endif
#endif

/*
  MORECORE is the name of the routine to call to obtain more memory
  from the system.  See below for general guidance on writing
  alternative MORECORE functions, as well as a version for WIN32 and a
  sample version for pre-OSX macos.
*/

#ifndef MORECORE
#define MORECORE sbrk
#endif


/*
  MORECORE_FAILURE is the value returned upon failure of MORECORE
  as well as mmap. Since it cannot be an otherwise valid memory address,
  and must reflect values of standard sys calls, you probably ought not
  try to redefine it.
*/

#ifndef MORECORE_FAILURE
#define MORECORE_FAILURE (-1)
#endif

/*
  If MORECORE_CONTIGUOUS is true, take advantage of fact that
  consecutive calls to MORECORE with positive arguments always return
  contiguous increasing addresses.  This is true of unix sbrk.  Even
  if not defined, when regions happen to be contiguous, malloc will
  permit allocations spanning regions obtained from different
  calls. But defining this when applicable enables some stronger
  consistency checks and space efficiencies.
*/


#ifndef MORECORE_CONTIGUOUS
#define MORECORE_CONTIGUOUS 1
#endif


/*
  The system page size. To the extent possible, this malloc manages
  memory from the system in page-size units.  Note that this value is
  cached during initialization into a field of malloc_state. So even
  if malloc_getpagesize is a function, it is only called once.

  The following mechanics for getpagesize were adapted from bsd/gnu
  getpagesize.h. If none of the system-probes here apply, a value of
  4096 is used, which should be OK: If they don't apply, then using
  the actual value probably doesn't impact performance.
*/

#ifndef malloc_getpagesize

#ifndef LACKS_UNISTD_H
#  include <unistd.h>
#endif

#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
#    ifndef _SC_PAGE_SIZE
#      define _SC_PAGE_SIZE _SC_PAGESIZE
#    endif
#  endif

#  ifdef _SC_PAGE_SIZE
#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
#  else
#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
       extern size_t getpagesize();
#      define malloc_getpagesize getpagesize()
#    else
#      ifdef WIN32 /* use supplied emulation of getpagesize */
#        define malloc_getpagesize getpagesize() 
#      else
#        ifndef LACKS_SYS_PARAM_H
#          include <sys/param.h>
#        endif
#        ifdef EXEC_PAGESIZE
#          define malloc_getpagesize EXEC_PAGESIZE
#        else
#          ifdef NBPG
#            ifndef CLSIZE
#              define malloc_getpagesize NBPG
#            else
#              define malloc_getpagesize (NBPG * CLSIZE)
#            endif
#          else
#            ifdef NBPC
#              define malloc_getpagesize NBPC
#            else
#              ifdef PAGESIZE
#                define malloc_getpagesize PAGESIZE
#              else /* just guess */
#                define malloc_getpagesize (4096) 
#              endif
#            endif
#          endif
#        endif
#      endif
#    endif
#  endif
#endif


/* Two-phase Name mangling */

#ifndef USE_PUBLIC_MALLOC_WRAPPERS
#define cALLOc      public_cALLOc
#define fREe        public_fREe
#define cFREe       public_cFREe
#define mALLOc      public_mALLOc
#define mEMALIGn    public_mEMALIGn
#define rEALLOc     public_rEALLOc
#define vALLOc      public_vALLOc
#define pVALLOc     public_pVALLOc
#define mALLINFo    public_mALLINFo
#define mALLOPt     public_mALLOPt
#define mTRIm       public_mTRIm
#define mSTATs      public_mSTATs
#define mUSABLe     public_mUSABLe
#endif

#ifdef USE_DL_PREFIX
#define public_cALLOc    dlcalloc
#define public_fREe      dlfree
#define public_cFREe     dlcfree
#define public_mALLOc    dlmalloc
#define public_mEMALIGn  dlmemalign
#define public_rEALLOc   dlrealloc
#define public_vALLOc    dlvalloc
#define public_pVALLOc   dlpvalloc
#define public_mALLINFo  dlmallinfo
#define public_mALLOPt   dlmallopt
#define public_mTRIm     dlmalloc_trim
#define public_mSTATs    dlmalloc_stats
#define public_mUSABLe   dlmalloc_usable_size
#else /* USE_DL_PREFIX */
#define public_cALLOc    calloc
#define public_fREe      free
#define public_cFREe     cfree
#define public_mALLOc    malloc
#define public_mEMALIGn  memalign
#define public_rEALLOc   realloc
#define public_vALLOc    valloc
#define public_pVALLOc   pvalloc
#define public_mALLINFo  mallinfo
#define public_mALLOPt   mallopt
#define public_mTRIm     malloc_trim
#define public_mSTATs    malloc_stats
#define public_mUSABLe   malloc_usable_size
#endif /* USE_DL_PREFIX */

#if __STD_C

Void_t* public_mALLOc(size_t);
void    public_fREe(Void_t*);
Void_t* public_rEALLOc(Void_t*, size_t);
Void_t* public_mEMALIGn(size_t, size_t);
Void_t* public_vALLOc(size_t);
Void_t* public_pVALLOc(size_t);
Void_t* public_cALLOc(size_t, size_t);
void    public_cFREe(Void_t*);
int     public_mTRIm(size_t);
size_t  public_mUSABLe(Void_t*);
void    public_mSTATs();
int     public_mALLOPt(int, int);
struct mallinfo public_mALLINFo(void);
#else
Void_t* public_mALLOc();
void    public_fREe();
Void_t* public_rEALLOc();
Void_t* public_mEMALIGn();
Void_t* public_vALLOc();
Void_t* public_pVALLOc();
Void_t* public_cALLOc();
void    public_cFREe();
int     public_mTRIm();
size_t  public_mUSABLe();
void    public_mSTATs();
int     public_mALLOPt();
struct mallinfo public_mALLINFo();
#endif


#ifdef __cplusplus
};  /* end of extern "C" */
#endif



/* ---------- To make a malloc.h, end cutting here ------------ */


/* Declarations of internal utilities defined below  */




#ifdef USE_PUBLIC_MALLOC_WRAPPERS
#if __STD_C

static Void_t* mALLOc(size_t);
static void    fREe(Void_t*);
static Void_t* rEALLOc(Void_t*, size_t);
static Void_t* mEMALIGn(size_t, size_t);
static Void_t* vALLOc(size_t);
static Void_t* pVALLOc(size_t);
static Void_t* cALLOc(size_t, size_t);
static void    cFREe(Void_t*);
static int     mTRIm(size_t);
static size_t  mUSABLe(Void_t*);
static void    mSTATs();
static int     mALLOPt(int, int);
static struct mallinfo mALLINFo(void);
#else
static Void_t* mALLOc();
static void    fREe();
static Void_t* rEALLOc();
static Void_t* mEMALIGn();
static Void_t* vALLOc();
static Void_t* pVALLOc();
static Void_t* cALLOc();
static void    cFREe();
static int     mTRIm();
static size_t  mUSABLe();
static void    mSTATs();
static int     mALLOPt();
static struct mallinfo mALLINFo();
#endif
#endif



/* ---------- public wrappers --------------- */

#ifdef USE_PUBLIC_MALLOC_WRAPPERS

/*
  MALLOC_PREACTION and MALLOC_POSTACTION should be
  defined to return 0 on success, and nonzero on failure.
  The return value of MALLOC_POSTACTION is currently ignored
  in wrapper functions since there is no reasonable default
  action to take on failure.
*/


#ifdef USE_MALLOC_LOCK

#ifdef WIN32

static int mALLOC_MUTEx;

#define MALLOC_PREACTION   slwait(&mALLOC_MUTEx)
#define MALLOC_POSTACTION  slrelease(&mALLOC_MUTEx)

#else

#include <pthread.h>

static pthread_mutex_t mALLOC_MUTEx = PTHREAD_MUTEX_INITIALIZER;

#define MALLOC_PREACTION   pthread_mutex_lock(&mALLOC_MUTEx)
#define MALLOC_POSTACTION  pthread_mutex_unlock(&mALLOC_MUTEx)

#endif /* USE_MALLOC_LOCK */

#else

/* Substitute anything you like for these */

#define MALLOC_PREACTION   (0)
#define MALLOC_POSTACTION  (0)

#endif

Void_t* public_mALLOc(size_t bytes) {
  Void_t* m;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  m = mALLOc(bytes);
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

void public_fREe(Void_t* m) {
  if (MALLOC_PREACTION != 0) {
    return;
  }
  fREe(m);
  if (MALLOC_POSTACTION != 0) {
  }
}

Void_t* public_rEALLOc(Void_t* m, size_t bytes) {
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  m = rEALLOc(m, bytes);
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

Void_t* public_mEMALIGn(size_t alignment, size_t bytes) {
  Void_t* m;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  m = mEMALIGn(alignment, bytes);
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

Void_t* public_vALLOc(size_t bytes) {
  Void_t* m;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  m = vALLOc(bytes);
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

Void_t* public_pVALLOc(size_t bytes) {
  Void_t* m;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  m = pVALLOc(bytes);
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

Void_t* public_cALLOc(size_t n, size_t elem_size) {
  Void_t* m;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  m = cALLOc(n, elem_size);
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

void public_cFREe(Void_t* m) {
  if (MALLOC_PREACTION != 0) {
    return;
  }
  cFREe(m);
  if (MALLOC_POSTACTION != 0) {
  }
}

int public_mTRIm(size_t s) {
  int result;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  result = mTRIm(s);
  if (MALLOC_POSTACTION != 0) {
  }
  return result;
}


size_t public_mUSABLe(Void_t* m) {
  size_t result;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  result = mUSABLe(m);
  if (MALLOC_POSTACTION != 0) {
  }
  return result;
}


void public_mSTATs() {
  if (MALLOC_PREACTION != 0) {
    return;
  }
  mSTATs();
  if (MALLOC_POSTACTION != 0) {
  }
}

struct mallinfo public_mALLINFo() {
  struct mallinfo m;
  if (MALLOC_PREACTION != 0) {
    return m;
  }
  m = mALLINFo();
  if (MALLOC_POSTACTION != 0) {
  }
  return m;
}

int public_mALLOPt(int p, int v) {
  int result;
  if (MALLOC_PREACTION != 0) {
    return 0;
  }
  result = mALLOPt(p, v);
  if (MALLOC_POSTACTION != 0) {
  }
  return result;
}

#endif



/* ------------- Optional versions of memcopy ---------------- */


#if USE_MEMCPY

#define MALLOC_COPY(dest, src, nbytes, overlap) \
 ((overlap) ? memmove(dest, src, nbytes) : memcpy(dest, src, nbytes))
#define MALLOC_ZERO(dest, nbytes)       memset(dest, 0,   nbytes)

#else /* !USE_MEMCPY */

/* Use Duff's device for good zeroing/copying performance. */

#define MALLOC_ZERO(charp, nbytes)                                            \
do {                                                                          \
  INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
  switch (mctmp) {                                                            \
    case 0: for(;;) { *mzp++ = 0;                                             \
    case 7:           *mzp++ = 0;                                             \
    case 6:           *mzp++ = 0;                                             \
    case 5:           *mzp++ = 0;                                             \
    case 4:           *mzp++ = 0;                                             \
    case 3:           *mzp++ = 0;                                             \
    case 2:           *mzp++ = 0;                                             \
    case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
  }                                                                           \
} while(0)

/* For overlapping case, dest is always _below_ src. */

#define MALLOC_COPY(dest,src,nbytes,overlap)                                  \
do {                                                                          \
  INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
  INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
  long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
  if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
  switch (mctmp) {                                                            \
    case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
    case 7:           *mcdst++ = *mcsrc++;                                    \
    case 6:           *mcdst++ = *mcsrc++;                                    \
    case 5:           *mcdst++ = *mcsrc++;                                    \
    case 4:           *mcdst++ = *mcsrc++;                                    \
    case 3:           *mcdst++ = *mcsrc++;                                    \
    case 2:           *mcdst++ = *mcsrc++;                                    \
    case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
  }                                                                           \
} while(0)

#endif

/* ------------------ MMAP support ------------------  */


#if HAVE_MMAP

#include <fcntl.h>
#ifndef LACKS_SYS_MMAN_H
#include <sys/mman.h>
#endif

#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS MAP_ANON
#endif


/* 
   Nearly all versions of mmap support MAP_ANONYMOUS, 
   so the following is unlikely to be needed, but is
   supplied just in case.
*/

#ifndef MAP_ANONYMOUS

static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */

#define MMAP(addr, size, prot, flags) ((dev_zero_fd < 0) ? \
 (dev_zero_fd = open("/dev/zero", O_RDWR), \
  mmap((addr), (size), (prot), (flags), dev_zero_fd, 0)) : \
   mmap((addr), (size), (prot), (flags), dev_zero_fd, 0))

#else

#define MMAP(addr, size, prot, flags) \
 (mmap((addr), (size), (prot), (flags)|MAP_ANONYMOUS, -1, 0))

#endif

#endif /* HAVE_MMAP */


/* ---------- Alternative MORECORE functions ------------ */


/*
  General Requirements for MORECORE.

  The MORECORE function must have the following properties:

  If MORECORE_CONTIGUOUS is false:

    * MORECORE must allocate in multiples of pagesize. It will
      only be called with arguments that are multiples of pagesize.

    * MORECORE must page-align. That is, MORECORE(0) must
      return an address at a page boundary.

  else (i.e. If MORECORE_CONTIGUOUS is true):

    * Consecutive calls to MORECORE with positive arguments
      return increasing addresses, indicating that space has been
      contiguously extended.

    * MORECORE need not allocate in multiples of pagesize.
      Calls to MORECORE need not have args of multiples of pagesize.

    * MORECORE need not page-align.

  In either case:

    * MORECORE may allocate more memory than requested. (Or even less,
      but this will generally result in a malloc failure.)

    * MORECORE must not allocate memory when given argument zero, but
      instead return one past the end address of memory from previous
      nonzero call. This malloc does NOT call MORECORE(0)
      until at least one call with positive arguments is made, so
      the initial value returned is not important.

    * Even though consecutive calls to MORECORE need not return contiguous
      addresses, it must be OK for malloc'ed chunks to span multiple
      regions in those cases where they do happen to be contiguous.

    * MORECORE need not handle negative arguments -- it may instead
      just return MORECORE_FAILURE when given negative arguments.
      Negative arguments are always multiples of pagesize. MORECORE
      must not misinterpret negative args as large positive unsigned
      args.

  There is some variation across systems about the type of the
  argument to sbrk/MORECORE. If size_t is unsigned, then it cannot
  actually be size_t, because sbrk supports negative args, so it is
  normally the signed type of the same width as size_t (sometimes
  declared as "intptr_t", and sometimes "ptrdiff_t").  It doesn't much
  matter though. Internally, we use "long" as arguments, which should
  work across all reasonable possibilities.

  Additionally, if MORECORE ever returns failure for a positive
  request, and HAVE_MMAP is true, then mmap is used as a noncontiguous
  system allocator. This is a useful backup strategy for systems with
  holes in address spaces -- in this case sbrk cannot contiguously
  expand the heap, but mmap may be able to map noncontiguous space.
  If you'd like mmap to ALWAYS be used, you can define MORECORE to be
  a function that always returns MORECORE_FAILURE.

  If you are using this malloc with something other than unix sbrk to
  supply memory regions, you probably want to set MORECORE_CONTIGUOUS
  as false.  As an example, here is a custom allocator kindly
  contributed for pre-OSX macOS.  It uses virtually but not
  necessarily physically contiguous non-paged memory (locked in,
  present and won't get swapped out).  You can use it by uncommenting
  this section, adding some #includes, and setting up the appropriate
  defines above:

      #define MORECORE osMoreCore
      #define MORECORE_CONTIGUOUS 0

  There is also a shutdown routine that should somehow be called for
  cleanup upon program exit.

  #define MAX_POOL_ENTRIES 100
  #define MINIMUM_MORECORE_SIZE  (64 * 1024)
  static int next_os_pool;
  void *our_os_pools[MAX_POOL_ENTRIES];

  void *osMoreCore(int size)
  {
    void *ptr = 0;
    static void *sbrk_top = 0;

    if (size > 0)
    {
      if (size < MINIMUM_MORECORE_SIZE)
         size = MINIMUM_MORECORE_SIZE;
      if (CurrentExecutionLevel() == kTaskLevel)
         ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
      if (ptr == 0)
      {
        return (void *) MORECORE_FAILURE;
      }
      // save ptrs so they can be freed during cleanup
      our_os_pools[next_os_pool] = ptr;
      next_os_pool++;
      ptr = (void *) ((((unsigned long) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
      sbrk_top = (char *) ptr + size;
      return ptr;
    }
    else if (size < 0)
    {
      // we don't currently support shrink behavior
      return (void *) MORECORE_FAILURE;
    }
    else
    {
      return sbrk_top;
    }
  }

  // cleanup any allocated memory pools
  // called as last thing before shutting down driver

  void osCleanupMem(void)
  {
    void **ptr;

    for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
      if (*ptr)
      {
         PoolDeallocate(*ptr);
         *ptr = 0;
      }
  }

*/






/*
  -----------------------  Chunk representations -----------------------
*/


/*
  This struct declaration is misleading (but accurate and necessary).
  It declares a "view" into memory allowing access to necessary
  fields at known offsets from a given base. See explanation below.
*/

struct malloc_chunk {

  INTERNAL_SIZE_T      prev_size;  /* Size of previous chunk (if free).  */
  INTERNAL_SIZE_T      size;       /* Size in bytes, including overhead. */

  struct malloc_chunk* fd;         /* double links -- used only if free. */
  struct malloc_chunk* bk;
};


typedef struct malloc_chunk* mchunkptr;

/*

   malloc_chunk details:

    (The following includes lightly edited explanations by Colin Plumb.)

    Chunks of memory are maintained using a `boundary tag' method as
    described in e.g., Knuth or Standish.  (See the paper by Paul
    Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
    survey of such techniques.)  Sizes of free chunks are stored both
    in the front of each chunk and at the end.  This makes
    consolidating fragmented chunks into bigger chunks very fast.  The
    size fields also hold bits representing whether chunks are free or
    in use.

    An allocated chunk looks like this:


    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of previous chunk, if allocated            | |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of chunk, in bytes                         |P|
      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             User data starts here...                          .
            .                                                               .
            .             (malloc_usable_space() bytes)                     .
            .                                                               |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of chunk                                     |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


    Where "chunk" is the front of the chunk for the purpose of most of
    the malloc code, but "mem" is the pointer that is returned to the
    user.  "Nextchunk" is the beginning of the next contiguous chunk.

    Chunks always begin on even word boundries, so the mem portion
    (which is returned to the user) is also on an even word boundary, and
    thus double-word aligned.

    Free chunks are stored in circular doubly-linked lists, and look like this:

    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Size of previous chunk                            |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    `head:' |             Size of chunk, in bytes                         |P|
      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Forward pointer to next chunk in list             |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Back pointer to previous chunk in list            |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |             Unused space (may be 0 bytes long)                .
            .                                                               .
            .                                                               |
nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    `foot:' |             Size of chunk, in bytes                           |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    The P (PREV_INUSE) bit, stored in the unused low-order bit of the
    chunk size (which is always a multiple of two words), is an in-use
    bit for the *previous* chunk.  If that bit is *clear*, then the
    word before the current chunk size contains the previous chunk
    size, and can be used to find the front of the previous chunk.
    The very first chunk allocated always has this bit set,
    preventing access to non-existent (or non-owned) memory. If
    prev_inuse is set for any given chunk, then you CANNOT determine
    the size of the previous chunk, and might even get a memory
    addressing fault when trying to do so.

    Note that the `foot' of the current chunk is actually represented
    as the prev_size of the NEXT chunk. (This makes it easier to
    deal with alignments etc).

    The two exceptions to all this are

     1. The special chunk `top' doesn't bother using the
        trailing size field since there is no next contiguous chunk
        that would have to index off it. After initialization, `top'
        is forced to always exist.  If it would become less than
        MINSIZE bytes long, it is replenished.

     2. Chunks allocated via mmap, which have the second-lowest-order
        bit (IS_MMAPPED) set in their size fields.  Because they are
        allocated one-by-one, each must contain its own trailing size field.

*/




/*
  Size and alignment checks and conversions
*/

/* conversion from malloc headers to user pointers, and back */

#define chunk2mem(p)   ((Void_t*)((char*)(p) + 2*SIZE_SZ))
#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))

/* The smallest possible chunk */
#define MIN_CHUNK_SIZE        (sizeof(struct malloc_chunk))

/* The smallest size we can malloc is an aligned minimal chunk */

#define MINSIZE   ((MIN_CHUNK_SIZE+MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK)

/* Check if m has acceptable alignment */

#define aligned_OK(m)  (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)

/* 
   Check for negative/huge sizes.
   This cannot just test for < 0 because argument might
   be an unsigned type of uncertain width.
*/

#define IS_NEGATIVE(x) \
  ((unsigned long)x >= \
   (unsigned long)((((INTERNAL_SIZE_T)(1)) << ((SIZE_SZ)*8 - 1))))


/* pad request bytes into a usable size -- internal version */

#define request2size(req)                                        \
  (((req) + SIZE_SZ + MALLOC_ALIGN_MASK < MINSIZE)  ?            \
   MINSIZE :                                                     \
   ((req) + SIZE_SZ + MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK)


/*
   Same, except check for negative/huge arguments.
   This lets through args that are positive but wrap into
   negatives when padded. However, these are trapped
   elsewhere.
*/

#define checked_request2size(req, sz)                                    \
   if (IS_NEGATIVE(req)) {                                               \
     MALLOC_FAILURE_ACTION;                                              \
     return 0;                                                           \
   }                                                                     \
   (sz) = request2size(req);





/*
  Physical chunk operations
*/


/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */

#define PREV_INUSE 0x1


/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */

#define IS_MMAPPED 0x2


/* Bits to mask off when extracting size */

#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)


/* Ptr to next physical malloc_chunk. */

#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))


/* Ptr to previous physical malloc_chunk */

#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))


/* Treat space at ptr + offset as a chunk */

#define chunk_at_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))





/*
  Dealing with use bits

  Note: IS_MMAPPED is intentionally not masked off from size field in
  macros for which mmapped chunks should never be seen. This should
  cause helpful core dumps to occur if it is tried by accident by
  people extending or adapting this malloc.

*/


/* extract p's inuse bit */

#define inuse(p)\
((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)


/* extract inuse bit of previous chunk */

#define prev_inuse(p)       ((p)->size & PREV_INUSE)


/* check for mmap()'ed chunk */

#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)


/* set/clear chunk as being inuse without otherwise disturbing */

#define set_inuse(p)\
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE

#define clear_inuse(p)\
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)


/* check/set/clear inuse bits in known places */

#define inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)

#define set_inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)

#define clear_inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))





/*
  Dealing with size fields
*/

/* Get size, ignoring use bits */

#define chunksize(p)         ((p)->size & ~(SIZE_BITS))

/* Set size at head, without disturbing its use bit */

#define set_head_size(p, s)  ((p)->size = (((p)->size & PREV_INUSE) | (s)))

/* Set size/use field */

#define set_head(p, s)       ((p)->size = (s))

/* Set size at footer (only when chunk is not in use) */

#define set_foot(p, s)       (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))






/*
  ------------------  Internal data structures --------------------

   All internal state is held in an instance of malloc_state defined
   below. There are no other static variables, except in two optional
   cases: 
   * If USE_MALLOC_LOCK is defined, the mALLOC_MUTEx declared
      above. 
   * If HAVE_MMAP is true, but mmap doesn't support
     MAP_ANONYMOUS, a dummy file descriptor for mmap.

   Beware of lots of tricks that minimize the total space
   requirements. The result is a little over 1K bytes (for 4byte
   pointers and size_t.)

*/

/*

  Bins

    An array of bin headers for free chunks. Each bin is doubly
    linked.  The bins are approximately proportionally (log) spaced.
    There are a lot of these bins (128). This may look excessive, but
    works very well in practice.  Most bins hold sizes that are
    unusual as malloc request sizes, but are more usual for fragments
    and consolidated sets of chunks, which is what these bins hold, so
    they can be found quickly.  All procedures maintain the invariant
    that no consolidated chunk physically borders another one, so each
    chunk in a list is known to be preceeded and followed by either
    inuse chunks or the ends of memory.

    Chunks in bins are kept in size order, with ties going to the
    approximately least recently used chunk. Ordering is irrelevant
    for the small bins, which all contain the same-sized chunks, but
    facilitates best-fit allocation for larger chunks. (These lists
    are just sequential. Keeping them in order almost never requires
    enough traversal to warrant using fancier ordered data
    structures.)  Chunks of the same size are linked with the most
    recently freed at the front, and allocations are taken from the
    back.  This results in LRU (FIFO) allocation order, which tends
    to give each chunk an equal opportunity to be consolidated with
    adjacent freed chunks, resulting in larger free chunks and less
    fragmentation.

    To simplify use in double-linked lists, each bin header acts
    as a malloc_chunk. This avoids special-casing for headers.
    But to conserve space and (mainly) improve locality, we allocate
    only the fd/bk pointers of bins, and then use repositioning tricks
    to treat these as the fields of a malloc_chunk*.  
*/

typedef struct malloc_chunk* mbinptr;

#define NBINS        128


/* addressing -- note that bin_at(0) does not exist */

#define bin_at(m, i) ((mbinptr)((char*)&((m)->bins[(i)<<1]) - (SIZE_SZ<<1)))


/* analog of ++bin */

#define next_bin(b)  ((mbinptr)((char*)(b) + (sizeof(mchunkptr)<<1)))


/* Reminders about list directionality within bins */

#define first(b)     ((b)->fd)
#define last(b)      ((b)->bk)

/*
   Take a chunk off a bin list
*/

#define unlink(P, BK, FD) {                                            \
  FD = P->fd;                                                          \
  BK = P->bk;                                                          \
  FD->bk = BK;                                                         \
  BK->fd = FD;                                                         \
}

/*
  Indexing bins

    Bins for sizes < 512 bytes contain chunks of all the same size, spaced
    8 bytes apart. Larger bins are approximately logarithmically spaced:

    64 bins of size       8
    32 bins of size      64
    16 bins of size     512
     8 bins of size    4096
     4 bins of size   32768
     2 bins of size  262144
     1 bin  of size what's left

    There is actually a little bit of slop in the numbers in bin_index
    for the sake of speed. This makes no difference elsewhere.

    The bins top out at around 1mb because we expect to service large
    chunks via mmap.

*/

/* The first NSMALLBIN bins (and fastbins) hold only one size */
#define NSMALLBINS         64
#define SMALLBIN_WIDTH      8
#define MIN_LARGE_SIZE    512

#define in_smallbin_range(sz)  ((sz) <  MIN_LARGE_SIZE)

#define smallbin_index(sz)     (((unsigned)(sz)) >> 3)

#define largebin_index(sz)                                                   \
(((((unsigned long)(sz)) >>  6) <= 32)?  56 + (((unsigned long)(sz)) >>  6): \
 ((((unsigned long)(sz)) >>  9) <= 20)?  91 + (((unsigned long)(sz)) >>  9): \
 ((((unsigned long)(sz)) >> 12) <= 10)? 110 + (((unsigned long)(sz)) >> 12): \
 ((((unsigned long)(sz)) >> 15) <=  4)? 119 + (((unsigned long)(sz)) >> 15): \
 ((((unsigned long)(sz)) >> 18) <=  2)? 124 + (((unsigned long)(sz)) >> 18): \
                                        126)

#define bin_index(sz) \
 ((in_smallbin_range(sz)) ? smallbin_index(sz) : largebin_index(sz))


/*
  Unsorted chunks

    All remainders from chunk splits, as well as all returned chunks,
    are first placed in the "unsorted" bin. They are then placed
    in regular bins after malloc gives them ONE chance to be used before
    binning. So, basically, the unsorted_chunks list acts as a queue,
    with chunks being placed on it in free (and malloc_consolidate),
    and taken off (to be either used or placed in bins) in malloc.
    
*/


/* The otherwise unindexable 1-bin is used to hold unsorted chunks. */

#define unsorted_chunks(M)          (bin_at(M, 1))


/*
  Top

    The top-most available chunk (i.e., the one bordering the end of
    available memory) is treated specially. It is never included in
    any bin, is used only if no other chunk is available, and is
    released back to the system if it is very large (see
    M_TRIM_THRESHOLD).  `top' is never properly linked to its bin
    since it is always handled specially.  Because top initially
    points to its own bin with initial zero size, thus forcing
    extension on the first malloc request, we avoid having any special
    code in malloc to check whether it even exists yet. But we still
    need to do so when getting memory from system, so we make
    initial_top treat the bin as a legal but unusable chunk during the
    interval between initialization and the first call to
    sYSMALLOc. (This is somewhat delicate, since it relies on
    the 2 preceding words to be zero during this interval as well.)
*/


/* Conveniently, the unsorted bin can be used as dummy top on first call */
#define initial_top(M)              (unsorted_chunks(M))

/*
  Binmap

    To help compensate for the large number of bins, a one-level index
    structure is used for bin-by-bin searching.  `binmap' is a
    bitvector recording whether bins are definitely empty so they can
    be skipped over during during traversals.  The bits are NOT always
    cleared as soon as bins are empty, but instead only
    when they are noticed to be empty during traversal in malloc.

*/

/* Conservatively use 32 bits per map word, even if on 64bit system */
#define BINMAPSHIFT      5
#define BITSPERMAP       (1U << BINMAPSHIFT)
#define BINMAPSIZE       (NBINS / BITSPERMAP)

#define idx2block(i)     ((i) >> BINMAPSHIFT)
#define idx2bit(i)       ((1U << ((i) & ((1U << BINMAPSHIFT)-1))))

#define mark_bin(m,i)    ((m)->binmap[idx2block(i)] |=  idx2bit(i))
#define unmark_bin(m,i)  ((m)->binmap[idx2block(i)] &= ~(idx2bit(i)))
#define get_binmap(m,i)  ((m)->binmap[idx2block(i)] &   idx2bit(i))


/*
  Fastbins

    An array of lists holding recently freed small chunks.  Fastbins
    are not doubly linked.  It is faster to single-link them, and
    since chunks are never removed from the middles of these lists,
    double linking is not necessary.

    Chunks in fastbins keep their inuse bit set, so they cannot
    be consolidated with other free chunks. malloc_consolidate
    releases all chunks in fastbins and consolidates them with
    other free chunks.
*/

typedef struct malloc_chunk* mfastbinptr;

/* offset 2 to use otherwise unindexable first 2 bins */
#define fastbin_index(sz)        ((((unsigned int)(sz)) >> 3) - 2)

/* The maximum fastbin request size we support */
#define MAX_FAST_SIZE     80

#define NFASTBINS  (fastbin_index(request2size(MAX_FAST_SIZE))+1)



/*
  Flag bit held in max_fast indicating that there probably are some
  fastbin chunks . It is set true on entering a chunk into any fastbin,
  and cleared only in malloc_consolidate.

  The truth value is inverted so that have_fastchunks will be true
  upon startup (since statics are zero-filled).
*/


#define have_fastchunks(M)    (((M)->max_fast &  1U) == 0)
#define clear_fastchunks(M)   ((M)->max_fast |=  1U)
#define set_fastchunks(M)     ((M)->max_fast &= ~1U)

/* 
   Initialization value of max_fast. 
   Use impossibly small value if 0.
   Value also has flag bit clear.
*/
#define req2max_fast(s) (((((s) == 0)? SMALLBIN_WIDTH: request2size(s))) | 1U)


/*
  NONCONTIGUOUS_REGIONS is a special value for sbrk_base indicating that
  MORECORE does not return contiguous regions. In this case, we do not check
  or assume that the address of each chunk is at least sbrk_base.  Otherwise,
  contiguity is exploited in merging together, when possible, results
  from consecutive MORECORE calls.

  The possible values for sbrk_base are:
    MORECORE_FAILURE:   
       MORECORE has not yet been called, but we expect contiguous space
    NONCONTIGUOUS_REGIONS: 
       we don't expect or rely on contiguous space
    any other legal address: 
       the first address returned by MORECORE when contiguous
*/

#define NONCONTIGUOUS_REGIONS ((char*)(-3))


/*
   ----------- Internal state representation and initialization -----------
*/


struct malloc_state {

  /* The maximum chunk size to be eligible for fastbin */
  INTERNAL_SIZE_T  max_fast;   /* low bit used as fastbin flag */

  /* Base of the topmost chunk -- not otherwise kept in a bin */
  mchunkptr        top;

  /* The remainder from the most recent split of a small request */
  mchunkptr        last_remainder;

  /* Fastbins */
  mfastbinptr      fastbins[NFASTBINS];

  /* Normal bins packed as described above */
  mchunkptr        bins[NBINS * 2];

  /* Bitmap of bins */
  unsigned int     binmap[BINMAPSIZE];

  /* Tunable parameters */
  unsigned long    trim_threshold;
  INTERNAL_SIZE_T  top_pad;
  INTERNAL_SIZE_T  mmap_threshold;

  /* Memory map support */
  int              n_mmaps;
  int              n_mmaps_max;
  int              max_n_mmaps;

  /* Bookkeeping for sbrk */
  unsigned int     pagesize;    /* Cache malloc_getpagesize */
  char*            sbrk_base;   /* first address returned by sbrk, 
                                   or NONCONTIGUOUS_REGIONS */
  /* Statistics */

  INTERNAL_SIZE_T  mmapped_mem;
  INTERNAL_SIZE_T  sbrked_mem;

  INTERNAL_SIZE_T  max_sbrked_mem;
  INTERNAL_SIZE_T  max_mmapped_mem;
  INTERNAL_SIZE_T  max_total_mem;
};

typedef struct malloc_state *mstate;

/* 
   There is exactly one instance of this struct in this malloc.

   If you are adapting this malloc in a way that does NOT use a static
   malloc_state, you MUST explicitly zero-fill it before using. This
   malloc relies on the property that malloc_state is initialized to
   all zeroes (as is true of C statics).

*/

static struct malloc_state av_;  /* never directly referenced */

/*
   All uses of av_ are via get_malloc_state().
   This simplifies construction of multithreaded, etc extensions.

   At most one call to get_malloc_state is made per invocation of
   the public versions of malloc, free, and all other routines
   except realloc, valloc, and vpalloc. Also, it is called
   in check* routines if DEBUG is set.
*/

#define get_malloc_state() (&(av_))

/*
  Initialize a malloc_state struct.

  This is called only from within malloc_consolidate, which needs
  be called in the same contexts anyway.  It is never called directly
  outside of malloc_consolidate because some optimizing compilers try
  to inline it at all call points, which turns out not to be an
  optimization at all. (Inlining it only in malloc_consolidate is fine though.)
*/

#if __STD_C
static void malloc_init_state(mstate av)
#else
static void malloc_init_state(av) mstate av;
#endif
{
  int     i;
  mbinptr bin;

  
  /* Uncomment this if you are not using a static av */
  /* MALLOC_ZERO(av, sizeof(struct malloc_state); */

  /* Establish circular links for normal bins */
  for (i = 1; i < NBINS; ++i) { 
    bin = bin_at(av,i);
    bin->fd = bin->bk = bin;
  }

  av->max_fast       = req2max_fast(DEFAULT_MXFAST);

  av->top_pad        = DEFAULT_TOP_PAD;
  av->n_mmaps_max    = DEFAULT_MMAP_MAX;
  av->mmap_threshold = DEFAULT_MMAP_THRESHOLD;

#if MORECORE_CONTIGUOUS
  av->trim_threshold = DEFAULT_TRIM_THRESHOLD;
  av->sbrk_base      = (char*)MORECORE_FAILURE;
#else
  av->trim_threshold = (unsigned long)(-1);
  av->sbrk_base      = NONCONTIGUOUS_REGIONS;
#endif

  av->top            = initial_top(av);
  av->pagesize       = malloc_getpagesize;
}

/* 
   Other internal utilities operating on mstates
*/

#if __STD_C
static Void_t* sYSMALLOc(INTERNAL_SIZE_T, mstate);
static int  sYSTRIm(size_t, mstate);
static void malloc_consolidate(mstate);
#else
static Void_t* sYSMALLOc();
static int  sYSTRIm();
static void malloc_consolidate();
#endif


/*
  Debugging support

  These routines make a number of assertions about the states
  of data structures that should be true at all times. If any
  are not true, it's very likely that a user program has somehow
  trashed memory. (It's also possible that there is a coding error
  in malloc. In which case, please report it!)

*/

#if ! DEBUG

#define check_chunk(P)
#define check_free_chunk(P)
#define check_inuse_chunk(P)
#define check_remalloced_chunk(P,N)
#define check_malloced_chunk(P,N)
#define check_malloc_state()

#else
#define check_chunk(P)              do_check_chunk(P)
#define check_free_chunk(P)         do_check_free_chunk(P)
#define check_inuse_chunk(P)        do_check_inuse_chunk(P)
#define check_remalloced_chunk(P,N) do_check_remalloced_chunk(P,N)
#define check_malloced_chunk(P,N)   do_check_malloced_chunk(P,N)
#define check_malloc_state()        do_check_malloc_state()


/*
  Properties of all chunks
*/

#if __STD_C
static void do_check_chunk(mchunkptr p)
#else
static void do_check_chunk(p) mchunkptr p;
#endif
{

  mstate av = get_malloc_state();
  unsigned long sz = chunksize(p);

  if (!chunk_is_mmapped(p)) {
    
    /* Has legal address ... */
    if (av->sbrk_base != NONCONTIGUOUS_REGIONS) {
      assert(((char*)p) >= ((char*)(av->sbrk_base)));
    }

    if (p != av->top) {
      if (av->sbrk_base != NONCONTIGUOUS_REGIONS) {
        assert(((char*)p + sz) <= ((char*)(av->top)));
      }
    }
    else {
      if (av->sbrk_base != NONCONTIGUOUS_REGIONS) {
        assert(((char*)p + sz) <= ((char*)(av->sbrk_base) + av->sbrked_mem));
      }
      /* top size is always at least MINSIZE */
      assert((long)(sz) >= (long)(MINSIZE));
      /* top predecessor always marked inuse */
      assert(prev_inuse(p));
    }
      
  }
  else {
#if HAVE_MMAP
    /* address is outside main heap  */
    /* unless mmap has been used as sbrk backup */
    if (av->sbrk_base != NONCONTIGUOUS_REGIONS) { 
      assert(! (((char*)p) >= ((char*)av->sbrk_base) &&
                ((char*)p) <  ((char*)(av->sbrk_base) + av->sbrked_mem)));
    }
    /* chunk is page-aligned */
    assert(((p->prev_size + sz) & (av->pagesize-1)) == 0);
    /* mem is aligned */
    assert(aligned_OK(chunk2mem(p)));
#else
    /* force an appropriate assert violation if debug set */
    assert(!chunk_is_mmapped(p));
#endif
  }

}

/*
  Properties of free chunks
*/


#if __STD_C
static void do_check_free_chunk(mchunkptr p)
#else
static void do_check_free_chunk(p) mchunkptr p;
#endif
{
  mstate av = get_malloc_state();

  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
  mchunkptr next = chunk_at_offset(p, sz);

  do_check_chunk(p);

  /* Chunk must claim to be free ... */
  assert(!inuse(p));
  assert (!chunk_is_mmapped(p));

  /* Unless a special marker, must have OK fields */
  if ((unsigned long)sz >= (unsigned long)MINSIZE)
  {
    assert((sz & MALLOC_ALIGN_MASK) == 0);
    assert(aligned_OK(chunk2mem(p)));
    /* ... matching footer field */
    assert(next->prev_size == sz);
    /* ... and is fully consolidated */
    assert(prev_inuse(p));
    assert (next == av->top || inuse(next));

    /* ... and has minimally sane links */
    assert(p->fd->bk == p);
    assert(p->bk->fd == p);
  }
  else /* markers are always of size SIZE_SZ */
    assert(sz == SIZE_SZ);
}

/*
  Properties of inuse chunks
*/


#if __STD_C
static void do_check_inuse_chunk(mchunkptr p)
#else
static void do_check_inuse_chunk(p) mchunkptr p;
#endif
{
  mstate av = get_malloc_state();
  mchunkptr next;
  do_check_chunk(p);

  if (chunk_is_mmapped(p))
    return; /* mmapped chunks have no next/prev */

  /* Check whether it claims to be in use ... */
  assert(inuse(p));

  next = next_chunk(p);

  /* ... and is surrounded by OK chunks.
    Since more things can be checked with free chunks than inuse ones,
    if an inuse chunk borders them and debug is on, it's worth doing them.
  */
  if (!prev_inuse(p))  {
    /* Note that we cannot even look at prev unless it is not inuse */
    mchunkptr prv = prev_chunk(p);
    assert(next_chunk(prv) == p);
    do_check_free_chunk(prv);
  }

  if (next == av->top) {
    assert(prev_inuse(next));
    assert(chunksize(next) >= MINSIZE);
  }
  else if (!inuse(next))
    do_check_free_chunk(next);

}

/*
  Properties of chunks recycled from fastbins
*/

#if __STD_C
static void do_check_remalloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
#else
static void do_check_remalloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
#endif
{

  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;

  do_check_inuse_chunk(p);

  /* Legal size ... */
  assert((sz & MALLOC_ALIGN_MASK) == 0);
  assert((long)sz - (long)MINSIZE >= 0);
  assert((long)sz - (long)s >= 0);
  assert((long)sz - (long)(s + MINSIZE) < 0);

  /* ... and alignment */
  assert(aligned_OK(chunk2mem(p)));

}

/*
  Properties of nonrecycled chunks at the point they are malloced
*/

#if __STD_C
static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
#else
static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
#endif
{
  /* same as recycled case ... */
  do_check_remalloced_chunk(p, s);

  /*
    ... plus,  must obey implementation invariant that prev_inuse is
    always true of any allocated chunk; i.e., that each allocated
    chunk borders either a previously allocated and still in-use
    chunk, or the base of its memory arena. This is ensured
    by making all allocations from the the `lowest' part of any found
    chunk.  This does not necessarily hold however for chunks
    recycled via fastbins.
  */

  assert(prev_inuse(p));
}


/*
  Properties of malloc_state.

  This may be useful for debugging malloc, as well as detecting user
  programmer errors that somehow write into malloc_state.
*/

static void do_check_malloc_state()
{
  mstate av = get_malloc_state();
  int i;
  mchunkptr p;
  mchunkptr q;
  mbinptr b;
  unsigned int biton;
  int empty;
  unsigned int idx;
  INTERNAL_SIZE_T size;
  unsigned long total = 0;
  int max_fast_bin;


  /* internal size_t must be no wider than pointer type */
  assert(sizeof(INTERNAL_SIZE_T) <= sizeof(char*));

  /* alignment is a power of 2 */
  assert((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-1)) == 0);

  /* cannot run remaining checks until fully initialized */
  if (av->top == 0 || av->top == initial_top(av))
    return;

  /* pagesize is a power of 2 */
  assert((av->pagesize & (av->pagesize-1)) == 0);

  /* properties of fastbins */

  /* max_fast is in allowed range */

  assert((av->max_fast & ~1) <= request2size(MAX_FAST_SIZE));

  max_fast_bin = fastbin_index(av->max_fast);

  for (i = 0; i < NFASTBINS; ++i) {
    p = av->fastbins[i];

    /* all bins past max_fast are empty */
    if (i > max_fast_bin)
      assert(p == 0);

    while (p != 0) {
      /* each chunk claims to be inuse */
      do_check_inuse_chunk(p);
      total += chunksize(p);
      /* chunk belongs in this bin */
      assert(fastbin_index(chunksize(p)) == i);
      p = p->fd;
    }
  }

  if (total != 0)
    assert(have_fastchunks(av));

  /* check normal bins */
  for (i = 1; i < NBINS; ++i) {
    b = bin_at(av,i);

    /* binmap is accurate (except for bin 1 == unsorted_chunks) */
    if (i >= 2) {
      biton = get_binmap(av,i);
      empty = last(b) == b;
      if (!biton)
        assert(empty);
      else if (!empty)
        assert(biton);
    }

    for (p = last(b); p != b; p = p->bk) {
      /* each chunk claims to be free */
      do_check_free_chunk(p);
      size = chunksize(p);
      total += size;
      if (i >= 2) {
        /* chunk belongs in bin */
        idx = bin_index(size);
        assert(idx == i);
        /* lists are sorted */
        assert(p->bk == b || chunksize(p->bk) >= chunksize(p));
      }
      /* chunk is followed by a legal chain of inuse chunks */
      for (q = next_chunk(p);
           q != av->top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
           q = next_chunk(q))
        do_check_inuse_chunk(q);

    }
  }

  /* top chunk is OK */
  check_chunk(av->top);

  /* sanity checks for statistics */

  assert(total <= (unsigned long)(av->max_total_mem));
  assert(av->n_mmaps >= 0);
  assert(av->n_mmaps <= av->n_mmaps_max);
  assert(av->n_mmaps <= av->max_n_mmaps);
  assert(av->max_n_mmaps <= av->n_mmaps_max);

  assert((unsigned long)(av->sbrked_mem) <=
         (unsigned long)(av->max_sbrked_mem));

  assert((unsigned long)(av->mmapped_mem) <=
         (unsigned long)(av->max_mmapped_mem));

  assert((unsigned long)(av->max_total_mem) >=
         (unsigned long)(av->mmapped_mem) + (unsigned long)(av->sbrked_mem));

}


#endif






/* ----------- Routines dealing with system allocation -------------- */

/*
  Handle malloc cases requiring more memory from system.
  malloc relays to sYSMALLOc if it cannot allocate out of
  existing memory.

  On entry, it is assumed that av->top does not have enough
  space to service request for nb bytes, thus requiring more meory
  from system.
*/

#if __STD_C
static Void_t* sYSMALLOc(INTERNAL_SIZE_T nb, mstate av)
#else
static Void_t* sYSMALLOc(nb, av) INTERNAL_SIZE_T nb; mstate av;
#endif
{
  mchunkptr       old_top;        /* incoming value of av->top */
  INTERNAL_SIZE_T old_size;       /* its size */
  char*           old_end;        /* its end address */

  long            size;           /* arg to first MORECORE or mmap call */
  char*           brk;            /* return value from MORECORE */
  char*           mm;             /* return value from mmap call*/

  long            correction;     /* arg to 2nd MORECORE call */
  char*           snd_brk;        /* 2nd return val */

  INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of new space */
  INTERNAL_SIZE_T end_misalign;   /* partial page left at end of new space */
  char*           aligned_brk;    /* aligned offset into brk */

  mchunkptr       p;              /* the allocated/returned chunk */
  mchunkptr       remainder;      /* remainder from allocation */
  long            remainder_size; /* its size */

  unsigned long   sum;            /* for updating stats */

  size_t          pagemask  = av->pagesize - 1;

  /*
    If have mmap, and the request size meets the mmap threshold, and
    the system supports mmap, and there are few enough currently
    allocated mmapped regions, and a call to mmap succeeds, try to
    directly map this request rather than expanding top.
  */

#if HAVE_MMAP
  if ((unsigned long)nb >= (unsigned long)(av->mmap_threshold) &&
      (av->n_mmaps < av->n_mmaps_max)) {

    /*
      Round up size to nearest page.  For mmapped chunks, the overhead
      is one SIZE_SZ unit larger than for normal chunks, because there
      is no following chunk whose prev_size field could be used.
    */
    size = (nb + SIZE_SZ + MALLOC_ALIGN_MASK + pagemask) & ~pagemask;
    
    mm = (char*)(MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE));

    if (mm != (char*)(MORECORE_FAILURE)) {

      /*
        The offset to the start of the mmapped region is stored
        in the prev_size field of the chunk. This allows us to adjust
        returned start address to meet alignment requirements here 
        and in memalign(), and still be able to compute proper
        address argument for later munmap in free() and realloc().
      */

      front_misalign = (INTERNAL_SIZE_T)chunk2mem(mm) & MALLOC_ALIGN_MASK;
      if (front_misalign > 0) {
        correction = MALLOC_ALIGNMENT - front_misalign;
        p = (mchunkptr)(mm + correction);
        p->prev_size = correction;
        set_head(p, (size - correction) |IS_MMAPPED);
      }
      else {
        p = (mchunkptr)mm;
        set_head(p, size|IS_MMAPPED);
      }

      check_chunk(p);
      
      /* update statistics */

      if (++av->n_mmaps > av->max_n_mmaps) 
        av->max_n_mmaps = av->n_mmaps;

      sum = av->mmapped_mem += size;
      if (sum > (unsigned long)(av->max_mmapped_mem)) 
        av->max_mmapped_mem = sum;
      sum += av->sbrked_mem;
      if (sum > (unsigned long)(av->max_total_mem)) 
        av->max_total_mem = sum;
      
      return chunk2mem(p);
    }
  }
#endif

  /* record incoming configuration of top */

  old_top  = av->top;
  old_size = chunksize(old_top);
  old_end  = (char*)(chunk_at_offset(old_top, old_size));

  brk = snd_brk = (char*)(MORECORE_FAILURE); 

  /* 
     If not the first time through, we require old_size to be
     at least MINSIZE and to have prev_inuse set.
  */

  assert(old_top == initial_top(av) || 
         ((unsigned long) (old_size) >= (unsigned long)(MINSIZE) &&
          prev_inuse(old_top)));


  /* Request enough space for nb + pad + overhead */

  size = nb + av->top_pad + MINSIZE;

  /*
    If contiguous, we can subtract out existing space that we hope to
    combine with new space. We add it back later only if
    we don't actually get contiguous space.
  */

  if (av->sbrk_base != NONCONTIGUOUS_REGIONS)
    size -= old_size;

  /*
    Round to a multiple of page size.
    If MORECORE is not contiguous, this ensures that we only call it
    with whole-page arguments.  And if MORECORE is contiguous and
    this is not first time through, this preserves page-alignment of
    previous calls. Otherwise, we re-correct anyway to page-align below.
  */

  size = (size + pagemask) & ~pagemask;

  /*
    Don't try to call MORECORE if argument is so big as to appear
    negative. Note that since mmap takes size_t arg, it may succeed
    below even if we cannot call MORECORE.
  */

  if (size > 0) 
    brk = (char*)(MORECORE(size));

  /*
    If have mmap, try using it as a backup when MORECORE fails. This
    is worth doing on systems that have "holes" in address space, so
    sbrk cannot extend to give contiguous space, but space is available
    elsewhere.  Note that we ignore mmap max count and threshold limits,
    since there is no reason to artificially limit use here.
  */

#if HAVE_MMAP
  if (brk == (char*)(MORECORE_FAILURE)) {

    /* Cannot merge with old top, so add its size back in */

    if (av->sbrk_base != NONCONTIGUOUS_REGIONS)
      size = (size + old_size + pagemask) & ~pagemask;

    /* If we are relying on mmap as backup, then use larger units */

    if ((unsigned long)size < (unsigned long)MMAP_AS_MORECORE_SIZE)
      size = MMAP_AS_MORECORE_SIZE;

    brk = (char*)(MMAP(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE));

    if (brk != (char*)(MORECORE_FAILURE)) {

      /* We do not need, and cannot use, another sbrk call to find end */
      snd_brk = brk + size;

      /* 
         Record that we no longer have a contiguous sbrk region. 
         After the first time mmap is used as backup, we cannot
         ever rely on contiguous space.
      */
      av->sbrk_base = NONCONTIGUOUS_REGIONS; 
    }
  }
#endif

  if (brk != (char*)(MORECORE_FAILURE)) {

    av->sbrked_mem += size;

    /*
      If MORECORE extends previous space, we can likewise extend top size.
    */
    
    if (brk == old_end && snd_brk == (char*)(MORECORE_FAILURE)) {
      set_head(old_top, (size + old_size) | PREV_INUSE);
    }
    
    /*
      Otherwise, make adjustments guided by the special values of 
      av->sbrk_base (MORECORE_FAILURE or NONCONTIGUOUS_REGIONS):
      
      * If the first time through or noncontiguous, we need to call sbrk
        just to find out where the end of memory lies.

      * We need to ensure that all returned chunks from malloc will meet
        MALLOC_ALIGNMENT

      * If there was an intervening foreign sbrk, we need to adjust sbrk
        request size to account for fact that we will not be able to
        combine new space with existing space in old_top.

      * Almost all systems internally allocate whole pages at a time, in
        which case we might as well use the whole last page of request.
        So we allocate enough more memory to hit a page boundary now,
        which in turn causes future contiguous calls to page-align.

    */
    
    else {
      front_misalign = 0;
      end_misalign = 0;
      correction = 0;
      aligned_brk = brk;
      
      /* handle contiguous cases */
      if (av->sbrk_base != NONCONTIGUOUS_REGIONS) { 
        
        /* Guarantee alignment of first new chunk made from this space */

        front_misalign = (INTERNAL_SIZE_T)chunk2mem(brk) & MALLOC_ALIGN_MASK;
        if (front_misalign > 0) {

          /*
            Skip over some bytes to arrive at an aligned position.
            We don't need to specially mark these wasted front bytes.
            They will never be accessed anyway because
            prev_inuse of av->top (and any chunk created from its start)
            is always true after initialization.
          */

          correction = MALLOC_ALIGNMENT - front_misalign;
          aligned_brk += correction;
        }
        
        /*
          If this isn't adjacent to a previous sbrk, then we will not
          be able to merge with old_top space, so must add to 2nd request.
        */
        
        correction += old_size;
        
        /* Pad out to hit a page boundary */

        end_misalign = (INTERNAL_SIZE_T)(brk + size + correction);
        correction += ((end_misalign + pagemask) & ~pagemask) - end_misalign;
        
        assert(correction >= 0);
        
        snd_brk = (char*)(MORECORE(correction));
        
        /*
          If can't allocate correction, try to at least find out current
          brk.  It might be enough to proceed without failing.
          
          Note that if second sbrk did NOT fail, we assume that space
          is contiguous with first sbrk. This is a safe assumption unless
          program is multithreaded but doesn't use locks and a foreign sbrk
          occurred between our first and second calls.
        */
        
        if (snd_brk == (char*)(MORECORE_FAILURE)) {
          correction = 0;
          snd_brk = (char*)(MORECORE(0));
        }
      }
      
      /* handle non-contiguous cases */
      else { 
        
        /* MORECORE/mmap must correctly align etc */
        assert(((unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK) == 0);
        
        /* Find out current end of memory */
        if (snd_brk == (char*)(MORECORE_FAILURE)) {
          snd_brk = (char*)(MORECORE(0));
        }
        
        /* This must lie on a page boundary */
        if (snd_brk != (char*)(MORECORE_FAILURE)) {
          assert(((INTERNAL_SIZE_T)(snd_brk) & pagemask) == 0);
        }
      }
      
      /* Adjust top based on results of second sbrk */
      if (snd_brk != (char*)(MORECORE_FAILURE)) {
       
        av->top = (mchunkptr)aligned_brk;
        set_head(av->top, (snd_brk - aligned_brk + correction) | PREV_INUSE);
        
        av->sbrked_mem += correction;
        
        /* If first time through and contiguous, record base */
        if (old_top == initial_top(av)) {
          if (av->sbrk_base == (char*)(MORECORE_FAILURE)) 
            av->sbrk_base = brk;
        }
        
        /*
          Otherwise, we either have a gap due to foreign sbrk or a
          non-contiguous region.  Insert a double fencepost at old_top
          to prevent consolidation with space we don't own. These
          fenceposts are artificial chunks that are marked as inuse
          and are in any case too small to use.  We need two to make
          sizes and alignments work out.
        */

        else {
          
          /* 
             Shrink old_top to insert fenceposts, keeping size a
             multiple of MALLOC_ALIGNMENT. 
          */
          old_size = (old_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
          set_head(old_top, old_size | PREV_INUSE);
          
          /*
            Note that the following assignments overwrite old_top when
            old_size was previously MINSIZE.  This is intentional. We
            need the fencepost, even if old_top otherwise gets lost.
          */
          chunk_at_offset(old_top, old_size          )->size =
            SIZE_SZ|PREV_INUSE;

          chunk_at_offset(old_top, old_size + SIZE_SZ)->size =
            SIZE_SZ|PREV_INUSE;
          
          /* If possible, release the rest. */
          if (old_size >= MINSIZE) 
            fREe(chunk2mem(old_top));

        }
      }
    }
    
    /* Update statistics */
    
    sum = av->sbrked_mem;
    if (sum > (unsigned long)(av->max_sbrked_mem))
      av->max_sbrked_mem = sum;
    
    sum += av->mmapped_mem;
    if (sum > (unsigned long)(av->max_total_mem))
      av->max_total_mem = sum;

    check_malloc_state();
    
    /* finally, do the allocation */
    
    p = av->top;
    size = chunksize(p);
    remainder_size = (long)size - (long)nb;
    
    /* check that one of the above allocation paths succeeded */
    if (remainder_size >= (long)MINSIZE) {
      remainder = chunk_at_offset(p, nb);
      av->top = remainder;
      set_head(p, nb | PREV_INUSE);
      set_head(remainder, remainder_size | PREV_INUSE);
      
      check_malloced_chunk(p, nb);
      return chunk2mem(p);
    }
  }

  /* catch all failure paths */
  MALLOC_FAILURE_ACTION;
  return 0;
}


/*
  sYSTRIm is an inverse of sorts to sYSMALLOc.
  It gives memory back to the system (via negative
  arguments to sbrk) if there is unused memory at the `high' end of
  the malloc pool. It is called automatically by free()
  when top space exceeds the trim threshold.
  returns 1 if it actually released any memory, else 0.
*/

#if __STD_C
static int sYSTRIm(size_t pad, mstate av)
#else
static int sYSTRIm(pad, av) size_t pad; mstate av;
#endif
{
  long  top_size;        /* Amount of top-most memory */
  long  extra;           /* Amount to release */
  long  released;        /* Amount actually released */
  char* current_brk;     /* address returned by pre-check sbrk call */
  char* new_brk;         /* address returned by post-check sbrk call */
  size_t pagesz;

  /* Don't bother trying if sbrk doesn't provide contiguous regions */
  if (av->sbrk_base != NONCONTIGUOUS_REGIONS) {

    pagesz = av->pagesize;
    top_size = chunksize(av->top);
    
    /* Release in pagesize units, keeping at least one page */
    extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
    
    if (extra > 0) {
      
      /*
        Only proceed if end of memory is where we last set it.
        This avoids problems if there were foreign sbrk calls.
      */
      current_brk = (char*)(MORECORE(0));
      if (current_brk == (char*)(av->top) + top_size) {
        
        /*
          Attempt to release memory. We ignore return value,
          and instead call again to find out where new end of memory is.
          This avoids problems if first call releases less than we asked,
          of if failure somehow altered brk value. (We could still
          encounter problems if it altered brk in some very bad way,
          but the only thing we can do is adjust anyway, which will cause
          some downstream failure.)
        */
        
        MORECORE(-extra);
        new_brk = (char*)(MORECORE(0));
        
        if (new_brk != (char*)MORECORE_FAILURE) {
          released = (long)(current_brk - new_brk);

          if (released != 0) {
            /* Success. Adjust top. */
            av->sbrked_mem -= released;
            set_head(av->top, (top_size - released) | PREV_INUSE);
            check_malloc_state();
            return 1;
          }
        }
      }
    }
  }

  return 0;
}

/* ----------------------- Main public routines ----------------------- */


/*
  Malloc routine. See running comments for algorithm description.
*/

#if __STD_C
Void_t* mALLOc(size_t bytes)
#else
  Void_t* mALLOc(bytes) size_t bytes;
#endif
{
  mstate av = get_malloc_state();

  INTERNAL_SIZE_T nb;               /* normalized request size */
  unsigned int    idx;              /* associated bin index */
  mbinptr         bin;              /* associated bin */
  mfastbinptr*    fb;               /* associated fastbin */

  mchunkptr       victim;           /* inspected/selected chunk */
  INTERNAL_SIZE_T size;             /* its size */
  int             victim_index;     /* its bin index */

  mchunkptr       remainder;        /* remainder from a split */
  long            remainder_size;   /* its size */

  unsigned int    block;            /* bit map traverser */
  unsigned int    bit;              /* bit map traverser */
  unsigned int    map;              /* current word of binmap */

  mchunkptr       fwd;              /* misc temp for linking */
  mchunkptr       bck;              /* misc temp for linking */


  /*
    Check request for legality and convert to internal form, nb.
    This rejects negative arguments when size_t is treated as
    signed. It also rejects arguments that are so large that the size
    appears negative when aligned and padded.  The converted form
    adds SIZE_T bytes overhead plus possibly more to obtain necessary
    alignment and/or to obtain a size of at least MINSIZE, the
    smallest allocatable size.
  */

  checked_request2size(bytes, nb);

  /*
    If the size qualifies as a fastbin, first check corresponding bin.
    This code is safe to execute even if av not yet initialized, so we
    can try it first, which saves some time on this fast path.
  */

  if (nb <= av->max_fast) { 
    fb = &(av->fastbins[(fastbin_index(nb))]);
    if ( (victim = *fb) != 0) {
      *fb = victim->fd;
      check_remalloced_chunk(victim, nb);
      return chunk2mem(victim);
    }
  }

  /*
    If a small request, check regular bin.  Since these "smallbins"
    hold one size each, no searching within bins is necessary.
    
    (If a large request, we need to wait until unsorted chunks are
    processed to find best fit. But for small ones, fits are exact
    anyway, so we can check now, which is faster.)
  */

  if (in_smallbin_range(nb)) {
    idx = smallbin_index(nb);
    bin = bin_at(av,idx);

    if ( (victim = last(bin)) != bin) {
      if (victim == 0) /* initialization check */
        malloc_consolidate(av);
      else {
        bck = victim->bk;
        set_inuse_bit_at_offset(victim, nb);
        bin->bk = bck;
        bck->fd = bin;
        
        check_malloced_chunk(victim, nb);
        return chunk2mem(victim);
      }
    }
  }

  /* 
     If a large request, consolidate fastbins before continuing.
     While it might look excessive to kill all fastbins before
     even seeing if there is space available, this avoids
     fragmentation problems normally associated with fastbins.
     Also, in practice, programs tend to have runs of either small or
     large requests, but less often mixtures, so consolidation is not 
     usually invoked all that often.
  */

  else {
    idx = largebin_index(nb);
    if (have_fastchunks(av)) /* consolidation/initialization check */
      malloc_consolidate(av);
  }


  /*
    Process recently freed or remaindered chunks, taking one only if
    it is exact fit, or, if a small request, it is the remainder from
    the most recent non-exact fit.  Place other traversed chunks in
    bins.  Note that this step is the only place in any routine where
    chunks are placed in bins.

    The outer loop here is needed because we might not realize until
    near the end of malloc that we should have consolidated, so must
    do so and retry. This happens at most once, and only when we would
    otherwise need to expand memory to service a "small" request.
  */

    
  for(;;) {    
    
    while ( (victim = unsorted_chunks(av)->bk) != unsorted_chunks(av)) {
      bck = victim->bk;
      size = chunksize(victim);

      /* 
         If a small request, try to use last remainder if it is the
         only chunk in unsorted bin.  This helps promote locality for
         runs of consecutive small requests. This is the only
         exception to best-fit.
      */

      if (in_smallbin_range(nb) && 
          victim == av->last_remainder &&
          bck == unsorted_chunks(av) &&
          (remainder_size = (long)size - (long)nb) >= (long)MINSIZE) {

        /* split and reattach remainder */
        remainder = chunk_at_offset(victim, nb);
        unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
        av->last_remainder = remainder; 
        remainder->bk = remainder->fd = unsorted_chunks(av);
        
        set_head(victim, nb | PREV_INUSE);
        set_head(remainder, remainder_size | PREV_INUSE);
        set_foot(remainder, remainder_size);
        
        check_malloced_chunk(victim, nb);
        return chunk2mem(victim);
      }
      
      /* remove from unsorted list */
      unsorted_chunks(av)->bk = bck;
      bck->fd = unsorted_chunks(av);
      
      /* Take now instead of binning if exact fit */
      
      if (size == nb) {
        set_inuse_bit_at_offset(victim, size);
        check_malloced_chunk(victim, nb);
        return chunk2mem(victim);
      }
      
      /* place chunk in bin */
      
      if (in_smallbin_range(size)) {
        victim_index = smallbin_index(size);
        bck = bin_at(av, victim_index);
        fwd = bck->fd;
      }
      else {
        victim_index = largebin_index(size);
        bck = bin_at(av, victim_index);
        fwd = bck->fd;

        /* maintain large bins in sorted order */
        if (fwd != bck) {
          /* if smaller than smallest, bypass loop below */
          if ((unsigned long)size <= 
              (unsigned long)(chunksize(bck->bk))) {
            fwd = bck;
            bck = bck->bk;
          }
          else {
            while (fwd != bck && 
                   (unsigned long)size < (unsigned long)(chunksize(fwd))) {
              fwd = fwd->fd;
            }
            bck = fwd->bk;
          }
        }
      }
      
      mark_bin(av, victim_index);
      victim->bk = bck;
      victim->fd = fwd;
      fwd->bk = victim;
      bck->fd = victim;
    }
   
    /*
      If a large request, scan through the chunks of current bin in
      sorted order to find smallest that fits.  This is the only step
      where an unbounded number of chunks might be scanned without doing
      anything useful with them. However the lists tend to be very
      short.
    */
      
    if (!in_smallbin_range(nb)) {
      bin = bin_at(av, idx);

      /* skip scan if largest chunk is too small */
      if ((victim = last(bin)) != bin &&
          (long)(chunksize(first(bin))) - (long)(nb) >= 0) {
        do {
          size = chunksize(victim);
          remainder_size = (long)size - (long)nb;
          
          if (remainder_size >= 0)  {
            unlink(victim, bck, fwd);
            
            /* Exhaust */
            if (remainder_size < (long)MINSIZE)  {
              set_inuse_bit_at_offset(victim, size);
              check_malloced_chunk(victim, nb);
              return chunk2mem(victim);
            }
            /* Split */
            else {
              remainder = chunk_at_offset(victim, nb);
              unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
              remainder->bk = remainder->fd = unsorted_chunks(av);
              set_head(victim, nb | PREV_INUSE);
              set_head(remainder, remainder_size | PREV_INUSE);
              set_foot(remainder, remainder_size);
              check_malloced_chunk(victim, nb);
              return chunk2mem(victim);
            }
          }
        } while ( (victim = victim->bk) != bin);
      }
    }    

    /*
      Search for a chunk by scanning bins, starting with next largest
      bin. This search is strictly by best-fit; i.e., the smallest
      (with ties going to approximately the least recently used) chunk
      that fits is selected.
      
      The bitmap avoids needing to check that most blocks are nonempty.
      The particular case of skipping all bins during warm-up phases
      when no chunks have been returned yet is faster than it might look.
    */
    
    ++idx;
    bin = bin_at(av,idx);
    block = idx2block(idx);
    map = av->binmap[block];
    bit = idx2bit(idx);
    
    for (;;) {
      /*
        Skip rest of block if there are no more set bits in this block.
      */
      
      if (bit > map || bit == 0) {
        for (;;) {
          if (++block >= BINMAPSIZE)  /* out of bins */
            break;

          else if ( (map = av->binmap[block]) != 0) {
            bin = bin_at(av, (block << BINMAPSHIFT));
            bit = 1;
            break;
          }
        }
        /* Optimizers seem to like this double-break better than goto */
        if (block >= BINMAPSIZE) 
          break;
      }
      
      /* Advance to bin with set bit. There must be one. */
      while ((bit & map) == 0) {
        bin = next_bin(bin);
        bit <<= 1;
      }
      
      victim = last(bin);
      
      /*  False alarm -- the bin is empty. Clear the bit. */
      if (victim == bin) {
        av->binmap[block] = map &= ~bit; /* Write through */
        bin = next_bin(bin);
        bit <<= 1;
      }
      
      /*  We know the first chunk in this bin is big enough to use. */
      else {
        size = chunksize(victim);
        remainder_size = (long)size - (long)nb;
        
        assert(remainder_size >= 0);
        
        /* unlink */
        bck = victim->bk;
        bin->bk = bck;
        bck->fd = bin;
        
        
        /* Exhaust */
        if (remainder_size < (long)MINSIZE) {
          set_inuse_bit_at_offset(victim, size);
          check_malloced_chunk(victim, nb);
          return chunk2mem(victim);
        }
        
        /* Split */
        else {
          remainder = chunk_at_offset(victim, nb);
          
          unsorted_chunks(av)->bk = unsorted_chunks(av)->fd = remainder;
          remainder->bk = remainder->fd = unsorted_chunks(av);
          /* advertise as last remainder */
          if (in_smallbin_range(nb)) 
            av->last_remainder = remainder; 
          
          set_head(victim, nb | PREV_INUSE);
          set_head(remainder, remainder_size | PREV_INUSE);
          set_foot(remainder, remainder_size);
          check_malloced_chunk(victim, nb);
          return chunk2mem(victim);
        }
      }
    }
    
    /*
      If large enough, split off the chunk bordering the end of memory
      ("top"). Note that this use of top is in accord with the best-fit search
      rule.  In effect, top is treated as larger (and thus less well
      fitting) than any other available chunk since it can be extended
      to be as large as necessary (up to system limitations).

      We require that "top" always exists (i.e., has size >= MINSIZE)
      after initialization, so if it would otherwise be exhuasted by
      current request, it is replenished. (Among the reasons for
      ensuring it exists is that we may need MINSIZE space to put in
      fenceposts in sysmalloc.)
    */

    victim = av->top;
    size = chunksize(victim);
    remainder_size = (long)size - (long)nb;
   
    if (remainder_size >= (long)MINSIZE) {
      remainder = chunk_at_offset(victim, nb);
      av->top = remainder;
      set_head(victim, nb | PREV_INUSE);
      set_head(remainder, remainder_size | PREV_INUSE);
      
      check_malloced_chunk(victim, nb);
      return chunk2mem(victim);
    }
    
    /*
      If there is space available in fastbins, consolidate and retry,
      to possibly avoid expanding memory. This can occur only if nb is
      in smallbin range so we didn't consolidate upon entry.
    */

    else if (have_fastchunks(av)) {
      assert(in_smallbin_range(nb));
      idx = smallbin_index(nb); /* restore original bin index */
      malloc_consolidate(av);
    }

    /* 
       Otherwise, relay to handle system-dependent cases 
    */
    else 
      return sYSMALLOc(nb, av);    
  }
}




/*
  Free routine. See running comments for algorithm description.
*/

#if __STD_C
void fREe(Void_t* mem)
#else
void fREe(mem) Void_t* mem;
#endif
{
  mstate av = get_malloc_state();

  mchunkptr       p;           /* chunk corresponding to mem */
  INTERNAL_SIZE_T size;        /* its size */
  mfastbinptr*    fb;          /* associated fastbin */
  mchunkptr       nextchunk;   /* next contiguous chunk */
  INTERNAL_SIZE_T nextsize;    /* its size */
  int             nextinuse;   /* true if nextchunk is used */
  INTERNAL_SIZE_T prevsize;    /* size of previous contiguous chunk */
  mchunkptr       bck;         /* misc temp for linking */
  mchunkptr       fwd;         /* misc temp for linking */


  /* free(0) has no effect */
  if (mem != 0) {

    p = mem2chunk(mem);
    check_inuse_chunk(p);

    size = chunksize(p);

    /*
      If eligible, place chunk on a fastbin so it can be found
      and used quickly in malloc.
    */

    if ((unsigned long)size <= (unsigned long)av->max_fast

#if TRIM_FASTBINS
        /* 
           If TRIM_FASTBINS set, don't place chunks
           bordering top into fastbins
        */
        && (chunk_at_offset(p, size) != av->top)
#endif
        ) {

      set_fastchunks(av);
      fb = &(av->fastbins[fastbin_index(size)]);
      p->fd = *fb;
      *fb = p;
    }

    /*
       Consolidate non-mmapped chunks as they arrive.
    */

    else if (!chunk_is_mmapped(p)) {

      nextchunk = chunk_at_offset(p, size);

      /* consolidate backward */
      if (!prev_inuse(p)) {
        prevsize = p->prev_size;
        size += prevsize;
        p = chunk_at_offset(p, -((long) prevsize));
        unlink(p, bck, fwd);
      }

      nextsize = chunksize(nextchunk);

      if (nextchunk != av->top) {

        /* get and clear inuse bit */
        nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
        set_head(nextchunk, nextsize);

        /* consolidate forward */
        if (!nextinuse) {
          unlink(nextchunk, bck, fwd);
          size += nextsize;
        }

        /*
          Place chunk in unsorted chunk list. Chunks are
          not placed into regular bins until after they have
          been given one chance to be used in malloc.
        */

        bck = unsorted_chunks(av);
        fwd = bck->fd;
        p->bk = bck;
        p->fd = fwd;
        bck->fd = p;
        fwd->bk = p;

        set_head(p, size | PREV_INUSE);
        set_foot(p, size);
      }

      /*
         If the chunk borders the current high end of memory,
         consolidate into top
      */

      else {
        size += nextsize;
        set_head(p, size | PREV_INUSE);
        av->top = p;

        /*
          If the total unused topmost memory exceeds trim
          threshold, ask malloc_trim to reduce top. 

          Unless max_fast is 0, we don't know if there are fastbins
          bordering top, so we cannot tell for sure whether threshold has
          been reached unless fastbins are consolidated.  But we don't
          want to consolidate on each free.  As a compromise,
          consolidation is performed if half the threshold is
          reached.

        */

        if ((unsigned long)(size) > (unsigned long)(av->trim_threshold / 2)) {
          if (have_fastchunks(av)) {
            malloc_consolidate(av);
            size = chunksize(av->top);
          }

          if ((unsigned long)(size) > (unsigned long)(av->trim_threshold)) 
            sYSTRIm(av->top_pad, av);
        }
      }
    }

    /*
      If the chunk was allocated via mmap, release via munmap()
      Note that if HAVE_MMAP is false but chunk_is_mmapped is
      true, then user must have overwritten memory. There's nothing
      we can do to catch this error unless DEBUG is set, in which case
      check_inuse_chunk (above) will have triggered error.
    */

    else {
#if HAVE_MMAP
      int ret;
      INTERNAL_SIZE_T offset = p->prev_size;
      av->n_mmaps--;
      av->mmapped_mem -= (size + offset);
      ret = munmap((char*)p - offset, size + offset);
      /* munmap returns non-zero on failure */
      assert(ret == 0);
#endif
    }
  }
}




/*
  malloc_consolidate is a specialized version of free() that tears
  down chunks held in fastbins.  Free itself cannot be used for this
  purpose since, among other things, it might place chunks back onto
  fastbins.  So, instead, we need to use a minor variant of the same
  code.
  
  Also, because this routine needs to be called the first time through
  malloc anyway, it turns out to be the perfect place to bury
  initialization code.
*/

#if __STD_C
static void malloc_consolidate(mstate av)
#else
static void malloc_consolidate(av) mstate av;
#endif
{
  mfastbinptr*    fb;
  mfastbinptr*    maxfb;
  mchunkptr       p;
  mchunkptr       nextp;
  mchunkptr       unsorted_bin;
  mchunkptr       first_unsorted;

  /* These have same use as in free() */
  mchunkptr       nextchunk;
  INTERNAL_SIZE_T size;
  INTERNAL_SIZE_T nextsize;
  INTERNAL_SIZE_T prevsize;
  int             nextinuse;
  mchunkptr       bck;
  mchunkptr       fwd;

  /*
    If max_fast is 0, we know that malloc hasn't
    yet been initialized, in which case do so.
  */

  if (av->max_fast == 0) {
    malloc_init_state(av);
    check_malloc_state();
  }
  else if (have_fastchunks(av)) {
    clear_fastchunks(av);
    
    unsorted_bin = unsorted_chunks(av);
    
    /*
      Remove each chunk from fast bin and consolidate it, placing it
      then in unsorted bin. Among other reasons for doing this,
      placing in unsorted bin avoids needing to calculate actual bins
      until malloc is sure that chunks aren't immediately going to be
      reused anyway.
    */
    
    maxfb = &(av->fastbins[fastbin_index(av->max_fast)]);
    fb = &(av->fastbins[0]);
    do {
      if ( (p = *fb) != 0) {
        *fb = 0;
        
        do {
          check_inuse_chunk(p);
          nextp = p->fd;
          
          /* Slightly streamlined version of consolidation code in free() */
          size = p->size & ~PREV_INUSE;
          nextchunk = chunk_at_offset(p, size);
          
          if (!prev_inuse(p)) {
            prevsize = p->prev_size;
            size += prevsize;
            p = chunk_at_offset(p, -((long) prevsize));
            unlink(p, bck, fwd);
          }
          
          nextsize = chunksize(nextchunk);
          
          if (nextchunk != av->top) {
            
            nextinuse = inuse_bit_at_offset(nextchunk, nextsize);
            set_head(nextchunk, nextsize);
            
            if (!nextinuse) {
              size += nextsize;
              unlink(nextchunk, bck, fwd);
            }
            
            first_unsorted = unsorted_bin->fd;
            unsorted_bin->fd = p;
            first_unsorted->bk = p;
            
            set_head(p, size | PREV_INUSE);
            p->bk = unsorted_bin;
            p->fd = first_unsorted;
            set_foot(p, size);
          }
          
          else {
            size += nextsize;
            set_head(p, size | PREV_INUSE);
            av->top = p;
          }
          
        } while ( (p = nextp) != 0);
        
      }
    } while (fb++ != maxfb);
  }
}





/*
  Realloc algorithm cases:

  * Chunks that were obtained via mmap cannot be extended or shrunk
    unless HAVE_MREMAP is defined, in which case mremap is used.
    Otherwise, if the reallocation is for additional space, they are
    copied.  If for less, they are just left alone.

  * Otherwise, if the reallocation is for additional space, and the
    chunk can be extended, it is, else a malloc-copy-free sequence is
    taken.  There are several different ways that a chunk could be
    extended. All are tried:

       * Extending forward into following adjacent free chunk.
       * Shifting backwards, joining preceding adjacent space
       * Both shifting backwards and extending forward.
       * Extending into newly sbrked space

  * If there is not enough memory available to realloc, realloc
    returns null, but does NOT free the existing space.

  * If the reallocation is for less space, the newly unused space is
    lopped off and freed. Unless the #define REALLOC_ZERO_BYTES_FREES
    is set, realloc with a size argument of zero (re)allocates a
    minimum-sized chunk.


  The old unix realloc convention of allowing the last-free'd chunk
  to be used as an argument to realloc is no longer supported.
  I don't know of any programs still relying on this feature,
  and allowing it would also allow too many other incorrect
  usages of realloc to be sensible.
*/

#if __STD_C
Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
#else
Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
#endif
{
  mstate av = get_malloc_state();

  INTERNAL_SIZE_T  nb;              /* padded request size */

  mchunkptr        oldp;            /* chunk corresponding to oldmem */
  INTERNAL_SIZE_T  oldsize;         /* its size */

  mchunkptr        newp;            /* chunk to return */
  INTERNAL_SIZE_T  newsize;         /* its size */
  Void_t*          newmem;          /* corresponding user mem */

  mchunkptr        next;            /* next contiguous chunk after oldp */
  mchunkptr        prev;            /* previous contiguous chunk before oldp */

  mchunkptr        remainder;       /* extra space at end of newp */
  long             remainder_size;  /* its size */

  mchunkptr        bck;             /* misc temp for linking */
  mchunkptr        fwd;             /* misc temp for linking */

  INTERNAL_SIZE_T  copysize;        /* bytes to copy */
  int              ncopies;         /* INTERNAL_SIZE_T words to copy */
  INTERNAL_SIZE_T* s;               /* copy source */ 
  INTERNAL_SIZE_T* d;               /* copy destination */


#ifdef REALLOC_ZERO_BYTES_FREES
  if (bytes == 0) {
    fREe(oldmem);
    return 0;
  }
#endif

  /* realloc of null is supposed to be same as malloc */
  if (oldmem == 0) return mALLOc(bytes);

  checked_request2size(bytes, nb);

  oldp    = mem2chunk(oldmem);
  oldsize = chunksize(oldp);

  check_inuse_chunk(oldp);

  if (!chunk_is_mmapped(oldp)) {

    if ((unsigned long)(oldsize) >= (unsigned long)(nb)) {
      /* already big enough; split below */
      newp = oldp;
      newsize = oldsize;
    }

    else {
      newp = 0;
      newsize = 0;

      next = chunk_at_offset(oldp, oldsize);

      if (next == av->top) {            /* Expand forward into top */
        newsize = oldsize + chunksize(next);

        if ((unsigned long)(newsize) >= (unsigned long)(nb + MINSIZE)) {
          set_head_size(oldp, nb);
          av->top = chunk_at_offset(oldp, nb);
          set_head(av->top, (newsize - nb) | PREV_INUSE);
          return chunk2mem(oldp);
        }

        else if (!prev_inuse(oldp)) {   /* Shift backwards + top */
          prev = prev_chunk(oldp);
          newsize += chunksize(prev);

          if ((unsigned long)(newsize) >= (unsigned long)(nb + MINSIZE)) {
            newp = prev;
            unlink(prev, bck, fwd);
            av->top = chunk_at_offset(newp, nb);
            set_head(av->top, (newsize - nb) | PREV_INUSE);
            newsize = nb; 
          }
        }
      }

      else if (!inuse(next)) {          /* Forward into next chunk */
        newsize = oldsize + chunksize(next);
        
        if (((unsigned long)(newsize) >= (unsigned long)(nb))) {
          newp = oldp;
          unlink(next, bck, fwd);
        }
        
        else if (!prev_inuse(oldp)) {   /* Forward + backward */
          prev = prev_chunk(oldp);
          newsize += chunksize(prev);
          
          if (((unsigned long)(newsize) >= (unsigned long)(nb))) {
            newp = prev;
            unlink(prev, bck, fwd);
            unlink(next, bck, fwd);
          }
        }
      }
      
      else if (!prev_inuse(oldp)) {     /* Backward only */
        prev = prev_chunk(oldp);
        newsize = oldsize + chunksize(prev);
        
        if ((unsigned long)(newsize) >= (unsigned long)(nb)) {
          newp = prev;
          unlink(prev, bck, fwd);
        }
      }
      
      if (newp != 0) {
        if (newp != oldp) {
          /* Backward copies are not worth unrolling */
          MALLOC_COPY(chunk2mem(newp), oldmem, oldsize - SIZE_SZ, 1);
        }
      }

      /* Must allocate */
      else {                  
        newmem = mALLOc(nb - MALLOC_ALIGN_MASK);
        if (newmem == 0)
          return 0; /* propagate failure */

        newp = mem2chunk(newmem);
        newsize = chunksize(newp);

        /*
          Avoid copy if newp is next chunk after oldp.
        */
        if (newp == next) {
          newsize += oldsize;
          newp = oldp;
        }
        else {

          /*
            Unroll copy of <= 36 bytes (72 if 8byte sizes)
            We know that contents have an odd number of
            INTERNAL_SIZE_T-sized words; minimally 3.
          */
          
          copysize = oldsize - SIZE_SZ;
          s = (INTERNAL_SIZE_T*)oldmem;
          d = (INTERNAL_SIZE_T*)(chunk2mem(newp));
          ncopies = copysize / sizeof(INTERNAL_SIZE_T);
          assert(ncopies >= 3);
          
          if (ncopies > 9)
            MALLOC_COPY(d, s, copysize, 0);
          
          else {
            *(d+0) = *(s+0);
            *(d+1) = *(s+1);
            *(d+2) = *(s+2);
            if (ncopies > 4) {
              *(d+3) = *(s+3);
              *(d+4) = *(s+4);
              if (ncopies > 6) {
                *(d+5) = *(s+5);
                *(d+6) = *(s+6);
                if (ncopies > 8) {
                  *(d+7) = *(s+7);
                  *(d+8) = *(s+8);
                }
              }
            }
          }

          fREe(oldmem);
          check_inuse_chunk(newp);
          return chunk2mem(newp);
        }
      }
    }


    /* If possible, free extra space in old or extended chunk */

    remainder_size = (long)newsize - (long)nb;
    assert(remainder_size >= 0);

    if (remainder_size >= (long)MINSIZE) { /* split remainder */
      remainder = chunk_at_offset(newp, nb);
      set_head_size(newp, nb);
      set_head(remainder, remainder_size | PREV_INUSE);
      /* Mark remainder as inuse so free() won't complain */
      set_inuse_bit_at_offset(remainder, remainder_size);
      fREe(chunk2mem(remainder)); 
    }

    else { /* not enough extra to split off */
      set_head_size(newp, newsize);
      set_inuse_bit_at_offset(newp, newsize);
    }

    check_inuse_chunk(newp);
    return chunk2mem(newp);
  }

  /*
    Handle mmap cases
  */

  else {
#if HAVE_MMAP

#if HAVE_MREMAP
    INTERNAL_SIZE_T offset = oldp->prev_size;
    size_t pagemask = av->pagesize - 1;
    char *cp;
    unsigned long sum;
    
    /* Note the extra SIZE_SZ overhead */
    newsize = (nb + offset + SIZE_SZ + pagemask) & ~pagemask;

    /* don't need to remap if still within same page */
    if (oldsize == newsize - offset) 
      return oldmem;

    cp = (char*)mremap((char*)oldp - offset, oldsize + offset, newsize, 1);
    
    if (cp != (char*)MORECORE_FAILURE) {

      newp = (mchunkptr)(cp + offset);
      set_head(newp, (newsize - offset)|IS_MMAPPED);
      
      assert(aligned_OK(chunk2mem(newp)));
      assert((newp->prev_size == offset));
      
      /* update statistics */
      sum = av->mmapped_mem += newsize - oldsize;
      if (sum > (unsigned long)(av->max_mmapped_mem)) 
        av->max_mmapped_mem = sum;
      sum += av->sbrked_mem;
      if (sum > (unsigned long)(av->max_total_mem)) 
        av->max_total_mem = sum;
      
      return chunk2mem(newp);
    }

#endif

    /* Note the extra SIZE_SZ overhead. */
    if ((long)oldsize - (long)SIZE_SZ >= (long)nb)
      newmem = oldmem; /* do nothing */
    else {
      /* Must alloc, copy, free. */
      newmem = mALLOc(nb - MALLOC_ALIGN_MASK);
      if (newmem != 0) {
        MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ, 0);
        fREe(oldmem);
      }
    }
    return newmem;

#else 
    /* If !HAVE_MMAP, but chunk_is_mmapped, user must have overwritten mem */
    check_malloc_state();
    MALLOC_FAILURE_ACTION;
    return 0;
#endif
  }

}




/*
  memalign requests more than enough space from malloc, finds a spot
  within that chunk that meets the alignment request, and then
  possibly frees the leading and trailing space.
  
  Alignments must be powers of two. If the argument is not a
  power of two, the nearest greater power is used.
  
  8-byte alignment is guaranteed by normal malloc calls, so don't
  bother calling memalign with an argument of 8 or less.
  
  Overreliance on memalign is a sure way to fragment space.
*/


#if __STD_C
Void_t* mEMALIGn(size_t alignment, size_t bytes)
#else
Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
#endif
{
  INTERNAL_SIZE_T nb;             /* padded  request size */
  char*           m;              /* memory returned by malloc call */
  mchunkptr       p;              /* corresponding chunk */
  char*           brk;            /* alignment point within p */
  mchunkptr       newp;           /* chunk to return */
  INTERNAL_SIZE_T newsize;        /* its size */
  INTERNAL_SIZE_T leadsize;       /* leading space befor alignment point */
  mchunkptr       remainder;      /* spare room at end to split off */
  long            remainder_size; /* its size */


  /* If need less alignment than we give anyway, just relay to malloc */

  if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);

  /* Otherwise, ensure that it is at least a minimum chunk size */

  if (alignment <  MINSIZE) alignment = MINSIZE;

  /* Make sure alignment is power of 2 (in case MINSIZE is not).  */
  if ((alignment & (alignment - 1)) != 0) {
    size_t a = MALLOC_ALIGNMENT * 2;
    while ((unsigned long)a < (unsigned long)alignment) a <<= 1;
    alignment = a;
  }

  checked_request2size(bytes, nb);

  /* Call malloc with worst case padding to hit alignment. */

  m  = (char*)(mALLOc(nb + alignment + MINSIZE));

  if (m == 0) return 0; /* propagate failure */

  p = mem2chunk(m);

  if ((((unsigned long)(m)) % alignment) != 0) { /* misaligned */

    /*
      Find an aligned spot inside chunk.  Since we need to give back
      leading space in a chunk of at least MINSIZE, if the first
      calculation places us at a spot with less than MINSIZE leader,
      we can move to the next aligned spot -- we've allocated enough
      total room so that this is always possible.
    */

    brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) &
                           -((signed long) alignment));
    if ((long)(brk - (char*)(p)) < (long)MINSIZE)
      brk = brk + alignment;

    newp = (mchunkptr)brk;
    leadsize = brk - (char*)(p);
    newsize = chunksize(p) - leadsize;

    /* For mmapped chunks, just adjust offset */
    if (chunk_is_mmapped(p)) {
      newp->prev_size = p->prev_size + leadsize;
      set_head(newp, newsize|IS_MMAPPED);
      return chunk2mem(newp);
    }

    /* Otherwise, give back leader, use the rest */

    set_head(newp, newsize | PREV_INUSE);
    set_inuse_bit_at_offset(newp, newsize);
    set_head_size(p, leadsize);
    fREe(chunk2mem(p));
    p = newp;

    assert (newsize >= nb &&
            (((unsigned long)(chunk2mem(p))) % alignment) == 0);
  }

  /* Also give back spare room at the end */
  if (!chunk_is_mmapped(p)) {

    remainder_size = (long)(chunksize(p)) - (long)nb;

    if (remainder_size >= (long)MINSIZE) {
      remainder = chunk_at_offset(p, nb);
      set_head(remainder, remainder_size | PREV_INUSE);
      set_head_size(p, nb);
      fREe(chunk2mem(remainder));
    }
  }

  check_inuse_chunk(p);
  return chunk2mem(p);

}





/*
  calloc calls malloc, then zeroes out the allocated chunk.
*/

#if __STD_C
Void_t* cALLOc(size_t n_elements, size_t elem_size)
#else
Void_t* cALLOc(n_elements, elem_size) size_t n_elements; size_t elem_size;
#endif
{
  mchunkptr p;
  INTERNAL_SIZE_T clearsize;
  int nclears;
  INTERNAL_SIZE_T* d;

  Void_t* mem = mALLOc(n_elements * elem_size);

  if (mem != 0) {
    p = mem2chunk(mem);
    if (!chunk_is_mmapped(p)) {  /* don't need to clear mmapped space */

      /*
        Unroll clear of <= 36 bytes (72 if 8byte sizes)
        We know that contents have an odd number of
        INTERNAL_SIZE_T-sized words; minimally 3.
      */

      d = (INTERNAL_SIZE_T*)mem;
      clearsize = chunksize(p) - SIZE_SZ;
      nclears = clearsize / sizeof(INTERNAL_SIZE_T);
      assert(nclears >= 3);

      if (nclears > 9)
        MALLOC_ZERO(d, clearsize);

      else {
        *(d+0) = 0;
        *(d+1) = 0;
        *(d+2) = 0;
        if (nclears > 4) {
          *(d+3) = 0;
          *(d+4) = 0;
          if (nclears > 6) {
            *(d+5) = 0;
            *(d+6) = 0;
            if (nclears > 8) {
              *(d+7) = 0;
              *(d+8) = 0;
            }
          }
        }
      }
    }
  }
  return mem;
}


/*
  cfree just calls free. It is needed/defined on some systems
  that pair it with calloc, presumably for odd historical reasons
  (such as: cfree is used in example code in first edition of K&R).
*/

#if __STD_C
void cFREe(Void_t *mem)
#else
void cFREe(mem) Void_t *mem;
#endif
{
  fREe(mem);
}






/*
  valloc just invokes memalign with alignment argument equal
  to the page size of the system (or as near to this as can
  be figured out from all the includes/defines above.)
*/

#if __STD_C
Void_t* vALLOc(size_t bytes)
#else
Void_t* vALLOc(bytes) size_t bytes;
#endif
{
  /* Ensure initialization/consolidation */
  mstate av = get_malloc_state();
  malloc_consolidate(av);
  return mEMALIGn(av->pagesize, bytes);
}

/*
  pvalloc just invokes valloc for the nearest pagesize
  that will accommodate request
*/


#if __STD_C
Void_t* pVALLOc(size_t bytes)
#else
Void_t* pVALLOc(bytes) size_t bytes;
#endif
{
  mstate av = get_malloc_state();
  size_t pagesz;

  /* Ensure initialization/consolidation */
  malloc_consolidate(av);

  pagesz = av->pagesize;
  return mEMALIGn(pagesz, (bytes + pagesz - 1) & ~(pagesz - 1));
}



/*
  Malloc_Trim  gives memory back to the system (via negative
  arguments to sbrk) if there is unused memory at the `high' end of
  the malloc pool. You can call this after freeing large blocks of
  memory to potentially reduce the system-level memory requirements
  of a program. However, it cannot guarantee to reduce memory. Under
  some allocation patterns, some large free blocks of memory will be
  locked between two used chunks, so they cannot be given back to
  the system.
  
  The `pad' argument to malloc_trim represents the amount of free
  trailing space to leave untrimmed. If this argument is zero,
  only the minimum amount of memory to maintain internal data
  structures will be left (one page or less). Non-zero arguments
  can be supplied to maintain enough trailing space to service
  future expected allocations without having to re-obtain memory
  from the system.
  
  Malloc_trim returns 1 if it actually released any memory, else 0.
*/

#if __STD_C
int mTRIm(size_t pad)
#else
int mTRIm(pad) size_t pad;
#endif
{
  mstate av = get_malloc_state();
  /* Ensure initialization/consolidation */
  malloc_consolidate(av);

  return sYSTRIm(pad, av);
}

/*
  malloc_usable_size tells you how many bytes you can actually use in
  an allocated chunk, which may be more than you requested (although
  often not). You can use this many bytes without worrying about
  overwriting other allocated objects. Not a particularly great
  programming practice, but still sometimes useful.
*/

#if __STD_C
size_t mUSABLe(Void_t* mem)
#else
size_t mUSABLe(mem) Void_t* mem;
#endif
{
  mchunkptr p;
  if (mem != 0) {
    p = mem2chunk(mem);
    if (chunk_is_mmapped(p))
      return chunksize(p) - 2*SIZE_SZ;
    else if (inuse(p))
      return chunksize(p) - SIZE_SZ;
  }
  return 0;
}





/*
  mallinfo returns a copy of updated current mallinfo.
*/

struct mallinfo mALLINFo()
{
  mstate av = get_malloc_state();
  struct mallinfo mi;
  int i;
  mbinptr b;
  mchunkptr p;
  INTERNAL_SIZE_T avail;
  int navail;
  int nfastblocks;
  int fastbytes;

  /* Ensure initialization */
  if (av->top == 0)  malloc_consolidate(av);

  check_malloc_state();

  /* Account for top */
  avail = chunksize(av->top);
  navail = 1;  /* top always exists */

  /* traverse fastbins */
  nfastblocks = 0;
  fastbytes = 0;

  for (i = 0; i < NFASTBINS; ++i) {
    for (p = av->fastbins[i]; p != 0; p = p->fd) {
      ++nfastblocks;
      fastbytes += chunksize(p);
    }
  }

  avail += fastbytes;

  /* traverse regular bins */
  for (i = 1; i < NBINS; ++i) {
    b = bin_at(av, i);
    for (p = last(b); p != b; p = p->bk) {
      avail += chunksize(p);
      navail++;
    }
  }

  mi.smblks = nfastblocks;
  mi.ordblks = navail;
  mi.fordblks = avail;
  mi.uordblks = av->sbrked_mem - avail;
  mi.arena = av->sbrked_mem;
  mi.hblks = av->n_mmaps;
  mi.hblkhd = av->mmapped_mem;
  mi.fsmblks = fastbytes;
  mi.keepcost = chunksize(av->top);
  mi.usmblks = av->max_total_mem;
  return mi;
}




/*
  malloc_stats prints on stderr the amount of space obtained from the
  system (both via sbrk and mmap), the maximum amount (which may be
  more than current if malloc_trim and/or munmap got called), and the
  current number of bytes allocated via malloc (or realloc, etc) but
  not yet freed. Note that this is the number of bytes allocated, not
  the number requested. It will be larger than the number requested
  because of alignment and bookkeeping overhead. Because it includes
  alignment wastage as being in use, this figure may be greater than zero 
  even when no user-level chunks are allocated.

  The reported current and maximum system memory can be inaccurate if
  a program makes other calls to system memory allocation functions
  (normally sbrk) outside of malloc.

  malloc_stats prints only the most commonly interesting statistics.
  More information can be obtained by calling mallinfo.
*/

void mSTATs()
{
  struct mallinfo mi = mALLINFo();

#ifdef WIN32
  {
    unsigned long free, reserved, committed;
    vminfo (&free, &reserved, &committed);
    fprintf(stderr, "free bytes       = %10lu\n", 
            free);
    fprintf(stderr, "reserved bytes   = %10lu\n", 
            reserved);
    fprintf(stderr, "committed bytes  = %10lu\n", 
            committed);
  }
#endif


  fprintf(stderr, "max system bytes = %10lu\n",
          (unsigned long)(mi.usmblks));
  fprintf(stderr, "system bytes     = %10lu\n",
          (unsigned long)(mi.arena + mi.hblkhd));
  fprintf(stderr, "in use bytes     = %10lu\n",
          (unsigned long)(mi.uordblks + mi.hblkhd));

#ifdef WIN32 
  {
    unsigned long kernel, user;
    if (cpuinfo (TRUE, &kernel, &user)) {
      fprintf(stderr, "kernel ms        = %10lu\n", 
              kernel);
      fprintf(stderr, "user ms          = %10lu\n", 
              user);
    }
  }
#endif
}




/*
  mallopt is the general SVID/XPG interface to tunable parameters.
  The format is to provide a (parameter-number, parameter-value)
  pair.  mallopt then sets the corresponding parameter to the
  argument value if it can (i.e., so long as the value is
  meaningful), and returns 1 if successful else 0.  See descriptions
  of tunable parameters above for meanings.
*/

#if __STD_C
int mALLOPt(int param_number, int value)
#else
int mALLOPt(param_number, value) int param_number; int value;
#endif
{
  mstate av = get_malloc_state();
  /* Ensure initialization/consolidation */
  malloc_consolidate(av);

  switch(param_number) {
  case M_MXFAST:
    if (value >= 0 && value <= MAX_FAST_SIZE) {
      av->max_fast = req2max_fast(value);
      return 1;
    }
    else
      return 0;

  case M_TRIM_THRESHOLD:
    av->trim_threshold = value;
    return 1;

  case M_TOP_PAD:
    av->top_pad = value;
    return 1;

  case M_MMAP_THRESHOLD:
    av->mmap_threshold = value;
    return 1;

  case M_MMAP_MAX:
#if HAVE_MMAP
    av->n_mmaps_max = value;
    return 1;
#else
    if (value != 0)
      return 0;
    else {
      av->n_mmaps_max = value;
      return 1;
    }
#endif

  default:
    return 0;
  }
}



/* -------------------------------------------------------------- */

/* 
   Emulation of sbrk for win32. 
   Donated by J. Walter <[email protected]>.
   For additional information about this code, and malloc on Win32, see 
     http://www.genesys-e.de/jwalter/

*/


#ifdef WIN32

#ifdef _DEBUG
/* #define TRACE */
#endif

/* Support for USE_MALLOC_LOCK */
#ifdef USE_MALLOC_LOCK

/* Wait for spin lock */
static int slwait (int *sl) {
    while (InterlockedCompareExchange ((void **) sl, (void *) 1, (void *) 0) != 0) 
            Sleep (0);
    return 0;
}

/* Release spin lock */
static int slrelease (int *sl) {
    InterlockedExchange (sl, 0);
    return 0;
}

#ifdef NEEDED
/* Spin lock for emulation code */
static int g_sl;
#endif

#endif /* USE_MALLOC_LOCK */

/* getpagesize for windows */
static long getpagesize (void) {
    static long g_pagesize = 0;
    if (! g_pagesize) {
        SYSTEM_INFO system_info;
        GetSystemInfo (&system_info);
        g_pagesize = system_info.dwPageSize;
    }
    return g_pagesize;
}
static long getregionsize (void) {
    static long g_regionsize = 0;
    if (! g_regionsize) {
        SYSTEM_INFO system_info;
        GetSystemInfo (&system_info);
        g_regionsize = system_info.dwAllocationGranularity;
    }
    return g_regionsize;
}

/* A region list entry */
typedef struct _region_list_entry {
    void *top_allocated;
    void *top_committed;
    void *top_reserved;
    long reserve_size;
    struct _region_list_entry *previous;
} region_list_entry;

/* Allocate and link a region entry in the region list */
static int region_list_append (region_list_entry **last, void *base_reserved, long reserve_size) {
    region_list_entry *next = HeapAlloc (GetProcessHeap (), 0, sizeof (region_list_entry));
    if (! next)
        return FALSE;
    next->top_allocated = (char *) base_reserved;
    next->top_committed = (char *) base_reserved;
    next->top_reserved = (char *) base_reserved + reserve_size;
    next->reserve_size = reserve_size;
    next->previous = *last;
    *last = next;
    return TRUE;
}
/* Free and unlink the last region entry from the region list */
static int region_list_remove (region_list_entry **last) {
    region_list_entry *previous = (*last)->previous;
    if (! HeapFree (GetProcessHeap (), sizeof (region_list_entry), *last))
        return FALSE;
    *last = previous;
    return TRUE;
}

#define CEIL(size,to)   (((size)+(to)-1)&~((to)-1))
#define FLOOR(size,to)  ((size)&~((to)-1))

#define SBRK_SCALE  0
/* #define SBRK_SCALE  1 */
/* #define SBRK_SCALE  2 */
/* #define SBRK_SCALE  4  */

/* sbrk for windows */
static void *sbrk (long size) {
    static long g_pagesize, g_my_pagesize;
    static long g_regionsize, g_my_regionsize;
    static region_list_entry *g_last;
    void *result = (void *) MORECORE_FAILURE;
#ifdef TRACE
    printf ("sbrk %d\n", size);
#endif
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
    /* Wait for spin lock */
    slwait (&g_sl);
#endif
    /* First time initialization */
    if (! g_pagesize) {
        g_pagesize = getpagesize ();
        g_my_pagesize = g_pagesize << SBRK_SCALE;
    }
    if (! g_regionsize) {
        g_regionsize = getregionsize ();
        g_my_regionsize = g_regionsize << SBRK_SCALE;
    }
    if (! g_last) {
        if (! region_list_append (&g_last, 0, 0)) 
           goto sbrk_exit;
    }
    /* Assert invariants */
    assert (g_last);
    assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_allocated &&
            g_last->top_allocated <= g_last->top_committed);
    assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_committed &&
            g_last->top_committed <= g_last->top_reserved &&
            (unsigned) g_last->top_committed % g_pagesize == 0);
    assert ((unsigned) g_last->top_reserved % g_regionsize == 0);
    assert ((unsigned) g_last->reserve_size % g_regionsize == 0);
    /* Allocation requested? */
    if (size >= 0) {
        /* Allocation size is the requested size */
        long allocate_size = size;
        /* Compute the size to commit */
        long to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed;
        /* Do we reach the commit limit? */
        if (to_commit > 0) {
            /* Round size to commit */
            long commit_size = CEIL (to_commit, g_my_pagesize);
            /* Compute the size to reserve */
            long to_reserve = (char *) g_last->top_committed + commit_size - (char *) g_last->top_reserved;
            /* Do we reach the reserve limit? */
            if (to_reserve > 0) {
                /* Compute the remaining size to commit in the current region */
                long remaining_commit_size = (char *) g_last->top_reserved - (char *) g_last->top_committed;
                if (remaining_commit_size > 0) {
                    /* Assert preconditions */
                    assert ((unsigned) g_last->top_committed % g_pagesize == 0);
                    assert (0 < remaining_commit_size && remaining_commit_size % g_pagesize == 0); {
                        /* Commit this */
                        void *base_committed = VirtualAlloc (g_last->top_committed, remaining_commit_size,
                                                                                         MEM_COMMIT, PAGE_READWRITE);
                        /* Check returned pointer for consistency */
                        if (base_committed != g_last->top_committed)
                            goto sbrk_exit;
                        /* Assert postconditions */
                        assert ((unsigned) base_committed % g_pagesize == 0);
#ifdef TRACE
                        printf ("Commit %p %d\n", base_committed, remaining_commit_size);
#endif
                        /* Adjust the regions commit top */
                        g_last->top_committed = (char *) base_committed + remaining_commit_size;
                    }
                } {
                    /* Now we are going to search and reserve. */
                    int contiguous = -1;
                    int found = FALSE;
                    MEMORY_BASIC_INFORMATION memory_info;
                    void *base_reserved;
                    long reserve_size;
                    do {
                        /* Assume contiguous memory */
                        contiguous = TRUE;
                        /* Round size to reserve */
                        reserve_size = CEIL (to_reserve, g_my_regionsize);
                        /* Start with the current region's top */
                        memory_info.BaseAddress = g_last->top_reserved;
                        /* Assert preconditions */
                        assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0);
                        assert (0 < reserve_size && reserve_size % g_regionsize == 0);
                        while (VirtualQuery (memory_info.BaseAddress, &memory_info, sizeof (memory_info))) {
                            /* Assert postconditions */
                            assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0);
#ifdef TRACE
                            printf ("Query %p %d %s\n", memory_info.BaseAddress, memory_info.RegionSize, 
                                    memory_info.State == MEM_FREE ? "FREE": 
                                    (memory_info.State == MEM_RESERVE ? "RESERVED":
                                     (memory_info.State == MEM_COMMIT ? "COMMITTED": "?")));
#endif
                            /* Region is free, well aligned and big enough: we are done */
                            if (memory_info.State == MEM_FREE &&
                                (unsigned) memory_info.BaseAddress % g_regionsize == 0 &&
                                memory_info.RegionSize >= (unsigned) reserve_size) {
                                found = TRUE;
                                break;
                            }
                            /* From now on we can't get contiguous memory! */
                            contiguous = FALSE;
                            /* Recompute size to reserve */
                            reserve_size = CEIL (allocate_size, g_my_regionsize);
                            memory_info.BaseAddress = (char *) memory_info.BaseAddress + memory_info.RegionSize;
                            /* Assert preconditions */
                            assert ((unsigned) memory_info.BaseAddress % g_pagesize == 0);
                            assert (0 < reserve_size && reserve_size % g_regionsize == 0);
                        }
                        /* Search failed? */
                        if (! found) 
                            goto sbrk_exit;
                        /* Assert preconditions */
                        assert ((unsigned) memory_info.BaseAddress % g_regionsize == 0);
                        assert (0 < reserve_size && reserve_size % g_regionsize == 0);
                        /* Try to reserve this */
                        base_reserved = VirtualAlloc (memory_info.BaseAddress, reserve_size, 
                                                                          MEM_RESERVE, PAGE_NOACCESS);
                        if (! base_reserved) {
                            int rc = GetLastError ();
                            if (rc != ERROR_INVALID_ADDRESS) 
                                goto sbrk_exit;
                        }
                        /* A null pointer signals (hopefully) a race condition with another thread. */
                        /* In this case, we try again. */
                    } while (! base_reserved);
                    /* Check returned pointer for consistency */
                    if (memory_info.BaseAddress && base_reserved != memory_info.BaseAddress)
                        goto sbrk_exit;
                    /* Assert postconditions */
                    assert ((unsigned) base_reserved % g_regionsize == 0);
#ifdef TRACE
                    printf ("Reserve %p %d\n", base_reserved, reserve_size);
#endif
                    /* Did we get contiguous memory? */
                    if (contiguous) {
                        long start_size = (char *) g_last->top_committed - (char *) g_last->top_allocated;
                        /* Adjust allocation size */
                        allocate_size -= start_size;
                        /* Adjust the regions allocation top */
                        g_last->top_allocated = g_last->top_committed;
                        /* Recompute the size to commit */
                        to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed;
                        /* Round size to commit */
                        commit_size = CEIL (to_commit, g_my_pagesize);
                    } 
                    /* Append the new region to the list */
                    if (! region_list_append (&g_last, base_reserved, reserve_size))
                        goto sbrk_exit;
                    /* Didn't we get contiguous memory? */
                    if (! contiguous) {
                        /* Recompute the size to commit */
                        to_commit = (char *) g_last->top_allocated + allocate_size - (char *) g_last->top_committed;
                        /* Round size to commit */
                        commit_size = CEIL (to_commit, g_my_pagesize);
                    }
                }
            } 
            /* Assert preconditions */
            assert ((unsigned) g_last->top_committed % g_pagesize == 0);
            assert (0 < commit_size && commit_size % g_pagesize == 0); {
                /* Commit this */
                void *base_committed = VirtualAlloc (g_last->top_committed, commit_size, 
                                                                             MEM_COMMIT, PAGE_READWRITE);
                /* Check returned pointer for consistency */
                if (base_committed != g_last->top_committed)
                    goto sbrk_exit;
                /* Assert postconditions */
                assert ((unsigned) base_committed % g_pagesize == 0);
#ifdef TRACE
                printf ("Commit %p %d\n", base_committed, commit_size);
#endif
                /* Adjust the regions commit top */
                g_last->top_committed = (char *) base_committed + commit_size;
            }
        } 
        /* Adjust the regions allocation top */
        g_last->top_allocated = (char *) g_last->top_allocated + allocate_size;
        result = (char *) g_last->top_allocated - size;
    /* Deallocation requested? */
    } else if (size < 0) {
        long deallocate_size = - size;
        /* As long as we have a region to release */
        while ((char *) g_last->top_allocated - deallocate_size < (char *) g_last->top_reserved - g_last->reserve_size) {
            /* Get the size to release */
            long release_size = g_last->reserve_size;
            /* Get the base address */
            void *base_reserved = (char *) g_last->top_reserved - release_size;
            /* Assert preconditions */
            assert ((unsigned) base_reserved % g_regionsize == 0); 
            assert (0 < release_size && release_size % g_regionsize == 0); {
                /* Release this */
                int rc = VirtualFree (base_reserved, 0, 
                                      MEM_RELEASE);
                /* Check returned code for consistency */
                if (! rc)
                    goto sbrk_exit;
#ifdef TRACE
                printf ("Release %p %d\n", base_reserved, release_size);
#endif
            }
            /* Adjust deallocation size */
            deallocate_size -= (char *) g_last->top_allocated - (char *) base_reserved;
            /* Remove the old region from the list */
            if (! region_list_remove (&g_last))
                goto sbrk_exit;
        } {
            /* Compute the size to decommit */
            long to_decommit = (char *) g_last->top_committed - ((char *) g_last->top_allocated - deallocate_size);
            if (to_decommit >= g_my_pagesize) {
                /* Compute the size to decommit */
                long decommit_size = FLOOR (to_decommit, g_my_pagesize);
                /*  Compute the base address */
                void *base_committed = (char *) g_last->top_committed - decommit_size;
                /* Assert preconditions */
                assert ((unsigned) base_committed % g_pagesize == 0);
                assert (0 < decommit_size && decommit_size % g_pagesize == 0); {
                    /* Decommit this */
                    int rc = VirtualFree ((char *) base_committed, decommit_size, 
                                          MEM_DECOMMIT);
                    /* Check returned code for consistency */
                    if (! rc)
                        goto sbrk_exit;
#ifdef TRACE
                    printf ("Decommit %p %d\n", base_committed, decommit_size);
#endif
                }
                /* Adjust deallocation size and regions commit and allocate top */
                deallocate_size -= (char *) g_last->top_allocated - (char *) base_committed;
                g_last->top_committed = base_committed;
                g_last->top_allocated = base_committed;
            }
        }
        /* Adjust regions allocate top */
        g_last->top_allocated = (char *) g_last->top_allocated - deallocate_size;
        /* Check for underflow */
        if ((char *) g_last->top_reserved - g_last->reserve_size > (char *) g_last->top_allocated ||
            g_last->top_allocated > g_last->top_committed) {
            /* Adjust regions allocate top */
            g_last->top_allocated = (char *) g_last->top_reserved - g_last->reserve_size;
            goto sbrk_exit;
        }
        result = g_last->top_allocated;
    }
    /* Assert invariants */
    assert (g_last);
    assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_allocated &&
            g_last->top_allocated <= g_last->top_committed);
    assert ((char *) g_last->top_reserved - g_last->reserve_size <= (char *) g_last->top_committed &&
            g_last->top_committed <= g_last->top_reserved &&
            (unsigned) g_last->top_committed % g_pagesize == 0);
    assert ((unsigned) g_last->top_reserved % g_regionsize == 0);
    assert ((unsigned) g_last->reserve_size % g_regionsize == 0);

sbrk_exit:
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
    /* Release spin lock */
    slrelease (&g_sl);
#endif
    return result;
}

/* mmap for windows */
static void *mmap (void *ptr, long size, long prot, long type, long handle, long arg) {
    static long g_pagesize;
    static long g_regionsize;
#ifdef TRACE
    printf ("mmap %d\n", size);
#endif
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
    /* Wait for spin lock */
    slwait (&g_sl);
#endif
    /* First time initialization */
    if (! g_pagesize) 
        g_pagesize = getpagesize ();
    if (! g_regionsize) 
        g_regionsize = getregionsize ();
    /* Assert preconditions */
    assert ((unsigned) ptr % g_regionsize == 0);
    assert (size % g_pagesize == 0);
    /* Allocate this */
    ptr = VirtualAlloc (ptr, size,
                                            MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, PAGE_READWRITE);
    if (! ptr) {
        ptr = (void *) MORECORE_FAILURE;
        goto mmap_exit;
    }
    /* Assert postconditions */
    assert ((unsigned) ptr % g_regionsize == 0);
#ifdef TRACE
    printf ("Commit %p %d\n", ptr, size);
#endif
mmap_exit:
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
    /* Release spin lock */
    slrelease (&g_sl);
#endif
    return ptr;
}

/* munmap for windows */
static long munmap (void *ptr, long size) {
    static long g_pagesize;
    static long g_regionsize;
    int rc = MUNMAP_FAILURE;
#ifdef TRACE
    printf ("munmap %p %d\n", ptr, size);
#endif
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
    /* Wait for spin lock */
    slwait (&g_sl);
#endif
    /* First time initialization */
    if (! g_pagesize) 
        g_pagesize = getpagesize ();
    if (! g_regionsize) 
        g_regionsize = getregionsize ();
    /* Assert preconditions */
    assert ((unsigned) ptr % g_regionsize == 0);
    assert (size % g_pagesize == 0);
    /* Free this */
    if (! VirtualFree (ptr, 0, 
                       MEM_RELEASE))
        goto munmap_exit;
    rc = 0;
#ifdef TRACE
    printf ("Release %p %d\n", ptr, size);
#endif
munmap_exit:
#if defined (USE_MALLOC_LOCK) && defined (NEEDED)
    /* Release spin lock */
    slrelease (&g_sl);
#endif
    return rc;
}

static void vminfo (unsigned long *free, unsigned long *reserved, unsigned long *committed) {
    MEMORY_BASIC_INFORMATION memory_info;
    memory_info.BaseAddress = 0;
    *free = *reserved = *committed = 0;
    while (VirtualQuery (memory_info.BaseAddress, &memory_info, sizeof (memory_info))) {
        switch (memory_info.State) {
        case MEM_FREE:
            *free += memory_info.RegionSize;
            break;
        case MEM_RESERVE:
            *reserved += memory_info.RegionSize;
            break;
        case MEM_COMMIT:
            *committed += memory_info.RegionSize;
            break;
        }
        memory_info.BaseAddress = (char *) memory_info.BaseAddress + memory_info.RegionSize;
    }
}

static int cpuinfo (int whole, unsigned long *kernel, unsigned long *user) {
    if (whole) {
        __int64 creation64, exit64, kernel64, user64;
        int rc = GetProcessTimes (GetCurrentProcess (), 
                                  (FILETIME *) &creation64,  
                                  (FILETIME *) &exit64, 
                                  (FILETIME *) &kernel64, 
                                  (FILETIME *) &user64);
        if (! rc) {
            *kernel = 0;
            *user = 0;
            return FALSE;
        } 
        *kernel = (unsigned long) (kernel64 / 10000);
        *user = (unsigned long) (user64 / 10000);
        return TRUE;
    } else {
        __int64 creation64, exit64, kernel64, user64;
        int rc = GetThreadTimes (GetCurrentThread (), 
                                 (FILETIME *) &creation64,  
                                 (FILETIME *) &exit64, 
                                 (FILETIME *) &kernel64, 
                                 (FILETIME *) &user64);
        if (! rc) {
            *kernel = 0;
            *user = 0;
            return FALSE;
        } 
        *kernel = (unsigned long) (kernel64 / 10000);
        *user = (unsigned long) (user64 / 10000);
        return TRUE;
    }
}

#endif /* WIN32 */

/*

History:

    V2.7.0
      * new WIN32 sbrk, mmap, munmap, lock code from <[email protected]>.
      * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for 
        helping test this.)
      * memalign: check alignment arg
      * realloc: use memmove when regions may overlap.
      * Collect all cases in malloc requiring system memory into sYSMALLOc
      * Use mmap as backup to sbrk, if available; fold these mmap-related 
        operations into others.
      * Place all internal state in malloc_state
      * Introduce fastbins (although similar to 2.5.1)
      * Many minor tunings and cosmetic improvements
      * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK 
      * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
        Thanks to Tony E. Bennett <[email protected]> and others.
      * Adjust request2size to fit with MALLOC_FAILURE_ACTION.
      * Include errno.h to support default failure action.
      * Further improve WIN32 'sbrk()' emulation's 'findRegion()' routine
        to avoid infinite loop when allocating initial memory larger
        than RESERVED_SIZE and/or subsequent memory larger than
        NEXT_SIZE.  Thanks to Andreas Mueller <a.mueller at paradatec.de>
        for finding this one.

    V2.6.6 Sun Dec  5 07:42:19 1999  Doug Lea  (dl at gee)
      * return null for negative arguments
      * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
         * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
          (e.g. WIN32 platforms)
         * Cleanup header file inclusion for WIN32 platforms
         * Cleanup code to avoid Microsoft Visual C++ compiler complaints
         * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
           memory allocation routines
         * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
         * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
           usage of 'assert' in non-WIN32 code
         * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
           avoid infinite loop
      * Always call 'fREe()' rather than 'free()'

    V2.6.5 Wed Jun 17 15:57:31 1998  Doug Lea  (dl at gee)
      * Fixed ordering problem with boundary-stamping

    V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
      * Added pvalloc, as recommended by H.J. Liu
      * Added 64bit pointer support mainly from Wolfram Gloger
      * Added anonymously donated WIN32 sbrk emulation
      * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
      * malloc_extend_top: fix mask error that caused wastage after
        foreign sbrks
      * Add linux mremap support code from HJ Liu

    V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
      * Integrated most documentation with the code.
      * Add support for mmap, with help from
        Wolfram Gloger ([email protected]).
      * Use last_remainder in more cases.
      * Pack bins using idea from  [email protected]
      * Use ordered bins instead of best-fit threshhold
      * Eliminate block-local decls to simplify tracing and debugging.
      * Support another case of realloc via move into top
      * Fix error occuring when initial sbrk_base not word-aligned.
      * Rely on page size for units instead of SBRK_UNIT to
        avoid surprises about sbrk alignment conventions.
      * Add mallinfo, mallopt. Thanks to Raymond Nijssen
        ([email protected]) for the suggestion.
      * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
      * More precautions for cases where other routines call sbrk,
        courtesy of Wolfram Gloger ([email protected]).
      * Added macros etc., allowing use in linux libc from
        H.J. Lu ([email protected])
      * Inverted this history list

    V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
      * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
      * Removed all preallocation code since under current scheme
        the work required to undo bad preallocations exceeds
        the work saved in good cases for most test programs.
      * No longer use return list or unconsolidated bins since
        no scheme using them consistently outperforms those that don't
        given above changes.
      * Use best fit for very large chunks to prevent some worst-cases.
      * Added some support for debugging

    V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
      * Removed footers when chunks are in use. Thanks to
        Paul Wilson ([email protected]) for the suggestion.

    V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
      * Added malloc_trim, with help from Wolfram Gloger
        ([email protected]).

    V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)

    V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
      * realloc: try to expand in both directions
      * malloc: swap order of clean-bin strategy;
      * realloc: only conditionally expand backwards
      * Try not to scavenge used bins
      * Use bin counts as a guide to preallocation
      * Occasionally bin return list chunks in first scan
      * Add a few optimizations from [email protected]

    V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
      * faster bin computation & slightly different binning
      * merged all consolidations to one part of malloc proper
         (eliminating old malloc_find_space & malloc_clean_bin)
      * Scan 2 returns chunks (not just 1)
      * Propagate failure in realloc if malloc returns 0
      * Add stuff to allow compilation on non-ANSI compilers
          from [email protected]

    V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
      * removed potential for odd address access in prev_chunk
      * removed dependency on getpagesize.h
      * misc cosmetics and a bit more internal documentation
      * anticosmetics: mangled names in macros to evade debugger strangeness
      * tested on sparc, hp-700, dec-mips, rs6000
          with gcc & native cc (hp, dec only) allowing
          Detlefs & Zorn comparison study (in SIGPLAN Notices.)

    Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
      * Based loosely on libg++-1.2X malloc. (It retains some of the overall
         structure of old version,  but most details differ.)

*/