cosmopolitan/third_party/dlmalloc/dlmalloc.c

#include "libc/nexgen32e/rdtsc.h"
#include "libc/dce.h"
#include "libc/assert.h"
#include "libc/rand/rand.h"
#include "libc/runtime/sysconf.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/runtime/runtime.h"
#include "libc/errno.h"
#include "libc/errno.h"
#include "libc/stdio/stdio.h"
#include "libc/intrin/kprintf.h"
#include "third_party/dlmalloc/vespene.internal.h"
#include "libc/calls/calls.h"
#include "libc/calls/calls.h"
#include "libc/runtime/runtime.h"
#include "libc/bits/weaken.h"
#include "libc/intrin/kprintf.h"
#include "libc/mem/mem.h"
// clang-format off

#define FOOTERS 0
#define MSPACES 0

#define HAVE_MMAP 1
#define HAVE_MREMAP 0
#define HAVE_MORECORE 0
#define USE_LOCKS 1
#define MORECORE_CONTIGUOUS 0
#define MALLOC_INSPECT_ALL 1

#if IsTiny()
#define INSECURE 1
#define PROCEED_ON_ERROR 1
#define ABORT_ON_ASSERT_FAILURE 0
#endif

#if IsModeDbg()
#define DEBUG 1
#endif

#define LACKS_UNISTD_H
#define LACKS_FCNTL_H
#define LACKS_SYS_PARAM_H
#define LACKS_SYS_MMAN_H
#define LACKS_STRINGS_H
#define LACKS_STRING_H
#define LACKS_SYS_TYPES_H
#define LACKS_ERRNO_H
#define LACKS_STDLIB_H
#define LACKS_SCHED_H
#define LACKS_TIME_H

/* Version identifier to allow people to support multiple versions */
#ifndef DLMALLOC_VERSION
#define DLMALLOC_VERSION 20806
#endif /* DLMALLOC_VERSION */

#ifndef DLMALLOC_EXPORT
#define DLMALLOC_EXPORT extern
#endif

/* The maximum possible size_t value has all bits set */
#define MAX_SIZE_T           (~(size_t)0)

#ifndef USE_LOCKS /* ensure true if spin or recursive locks set */
#define USE_LOCKS  ((defined(USE_SPIN_LOCKS) && USE_SPIN_LOCKS != 0) || \
                    (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0))
#endif /* USE_LOCKS */

#if USE_LOCKS /* Spin locks for gcc >= 4.1, older gcc on x86, MSC >= 1310 */
#if ((defined(__GNUC__) &&                                              \
      ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) ||      \
       defined(__i386__) || defined(__x86_64__))) ||                    \
     (defined(_MSC_VER) && _MSC_VER>=1310))
#ifndef USE_SPIN_LOCKS
#define USE_SPIN_LOCKS 1
#endif /* USE_SPIN_LOCKS */
#elif USE_SPIN_LOCKS
#error "USE_SPIN_LOCKS defined without implementation"
#endif /* ... locks available... */
#elif !defined(USE_SPIN_LOCKS)
#define USE_SPIN_LOCKS 0
#endif /* USE_LOCKS */

#ifndef ONLY_MSPACES
#define ONLY_MSPACES 0
#endif  /* ONLY_MSPACES */
#ifndef MSPACES
#if ONLY_MSPACES
#define MSPACES 1
#else   /* ONLY_MSPACES */
#define MSPACES 0
#endif  /* ONLY_MSPACES */
#endif  /* MSPACES */
#ifndef MALLOC_ALIGNMENT
#define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *)))
#endif  /* MALLOC_ALIGNMENT */
#ifndef FOOTERS
#define FOOTERS 0
#endif  /* FOOTERS */
#ifndef ABORT
#define ABORT  abort()
#endif  /* ABORT */
#ifndef ABORT_ON_ASSERT_FAILURE
#define ABORT_ON_ASSERT_FAILURE 1
#endif  /* ABORT_ON_ASSERT_FAILURE */
#ifndef PROCEED_ON_ERROR
#define PROCEED_ON_ERROR 0
#endif  /* PROCEED_ON_ERROR */

#ifndef INSECURE
#define INSECURE 0
#endif  /* INSECURE */
#ifndef MALLOC_INSPECT_ALL
#define MALLOC_INSPECT_ALL 0
#endif  /* MALLOC_INSPECT_ALL */
#ifndef HAVE_MMAP
#define HAVE_MMAP 1
#endif  /* HAVE_MMAP */
#ifndef MMAP_CLEARS
#define MMAP_CLEARS 1
#endif  /* MMAP_CLEARS */
#ifndef HAVE_MREMAP
#ifdef linux
#define HAVE_MREMAP 1
#define _GNU_SOURCE /* Turns on mremap() definition */
#else   /* linux */
#define HAVE_MREMAP 0
#endif  /* linux */
#endif  /* HAVE_MREMAP */
#ifndef MALLOC_FAILURE_ACTION
#define MALLOC_FAILURE_ACTION  errno = ENOMEM;
#endif  /* MALLOC_FAILURE_ACTION */
#ifndef HAVE_MORECORE
#if ONLY_MSPACES
#define HAVE_MORECORE 0
#else   /* ONLY_MSPACES */
#define HAVE_MORECORE 1
#endif  /* ONLY_MSPACES */
#endif  /* HAVE_MORECORE */
#if !HAVE_MORECORE
#define MORECORE_CONTIGUOUS 0
#else   /* !HAVE_MORECORE */
#define MORECORE_DEFAULT sbrk
#ifndef MORECORE_CONTIGUOUS
#define MORECORE_CONTIGUOUS 1
#endif  /* MORECORE_CONTIGUOUS */
#endif  /* HAVE_MORECORE */
#ifndef DEFAULT_GRANULARITY
#if (MORECORE_CONTIGUOUS || defined(WIN32))
#define DEFAULT_GRANULARITY (0)  /* 0 means to compute in init_mparams */
#else   /* MORECORE_CONTIGUOUS */
#define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
#endif  /* MORECORE_CONTIGUOUS */
#endif  /* DEFAULT_GRANULARITY */
#ifndef DEFAULT_TRIM_THRESHOLD
#ifndef MORECORE_CANNOT_TRIM
#define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
#else   /* MORECORE_CANNOT_TRIM */
#define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
#endif  /* MORECORE_CANNOT_TRIM */
#endif  /* DEFAULT_TRIM_THRESHOLD */
#ifndef DEFAULT_MMAP_THRESHOLD
#if HAVE_MMAP
#define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
#else   /* HAVE_MMAP */
#define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
#endif  /* HAVE_MMAP */
#endif  /* DEFAULT_MMAP_THRESHOLD */
#ifndef MAX_RELEASE_CHECK_RATE
#if HAVE_MMAP
#define MAX_RELEASE_CHECK_RATE 4095
#else
#define MAX_RELEASE_CHECK_RATE MAX_SIZE_T
#endif /* HAVE_MMAP */
#endif /* MAX_RELEASE_CHECK_RATE */
#ifndef USE_BUILTIN_FFS
#define USE_BUILTIN_FFS 0
#endif  /* USE_BUILTIN_FFS */
#ifndef USE_DEV_RANDOM
#define USE_DEV_RANDOM 0
#endif  /* USE_DEV_RANDOM */
#ifndef NO_MALLINFO
#define NO_MALLINFO 0
#endif  /* NO_MALLINFO */
#ifndef MALLINFO_FIELD_TYPE
#define MALLINFO_FIELD_TYPE size_t
#endif  /* MALLINFO_FIELD_TYPE */
#ifndef NO_MALLOC_STATS
#define NO_MALLOC_STATS 0
#endif  /* NO_MALLOC_STATS */
#ifndef NO_SEGMENT_TRAVERSAL
#define NO_SEGMENT_TRAVERSAL 0
#endif /* NO_SEGMENT_TRAVERSAL */

/*
  mallopt tuning options.  SVID/XPG defines four standard parameter
  numbers for mallopt, normally defined in malloc.h.  None of these
  are used in this malloc, so setting them has no effect. But this
  malloc does support the following options.
*/

#define M_TRIM_THRESHOLD     (-1)
#define M_GRANULARITY        (-2)
#define M_MMAP_THRESHOLD     (-3)

/* ------------------------ Mallinfo declarations ------------------------ */

/*
  Try to persuade compilers to inline. The most critical functions for
  inlining are defined as macros, so these aren't used for them.
*/

#define FORCEINLINE forceinline
#define NOINLINE dontinline

#if !ONLY_MSPACES

/* ------------------- Declarations of public routines ------------------- */

/*
  malloc(size_t n)
  Returns a pointer to a newly allocated chunk of at least n bytes, or
  null if no space is available, in which case errno is set to ENOMEM
  on ANSI C systems.

  If n is zero, malloc returns a minimum-sized chunk. (The minimum
  size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
  systems.)  Note that size_t is an unsigned type, so calls with
  arguments that would be negative if signed are interpreted as
  requests for huge amounts of space, which will often fail. The
  maximum supported value of n differs across systems, but is in all
  cases less than the maximum representable value of a size_t.
*/
DLMALLOC_EXPORT void* dlmalloc(size_t);

/*
  free(void* p)
  Releases the chunk of memory pointed to by p, that had been previously
  allocated using malloc or a related routine such as realloc.
  It has no effect if p is null. If p was not malloced or already
  freed, free(p) will by default cause the current program to abort.
*/
DLMALLOC_EXPORT void  dlfree(void*);

/*
  calloc(size_t n_elements, size_t element_size);
  Returns a pointer to n_elements * element_size bytes, with all locations
  set to zero.
*/
DLMALLOC_EXPORT void* dlcalloc(size_t, size_t);

/*
  realloc(void* p, size_t n)
  Returns 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. The algorithm
  prefers extending p in most cases when possible, otherwise it
  employs the equivalent of a malloc-copy-free sequence.

  If p is null, realloc is equivalent to malloc.

  If space is not available, realloc returns null, errno is set (if on
  ANSI) and p is NOT freed.

  if n is for fewer bytes than already held by p, the newly unused
  space is lopped off and freed if possible.  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 not supported.
*/
DLMALLOC_EXPORT void* dlrealloc(void*, size_t);

/*
  realloc_in_place(void* p, size_t n)
  Resizes the space allocated for p to size n, only if this can be
  done without moving p (i.e., only if there is adjacent space
  available if n is greater than p's current allocated size, or n is
  less than or equal to p's size). This may be used instead of plain
  realloc if an alternative allocation strategy is needed upon failure
  to expand space; for example, reallocation of a buffer that must be
  memory-aligned or cleared. You can use realloc_in_place to trigger
  these alternatives only when needed.

  Returns p if successful; otherwise null.
*/
DLMALLOC_EXPORT void* dlrealloc_in_place(void*, size_t);

/*
  memalign(size_t alignment, size_t n);
  Returns a pointer to a newly allocated chunk of n bytes, aligned
  in accord with the alignment argument.

  The alignment argument should be a power 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.
*/
DLMALLOC_EXPORT void* dlmemalign(size_t, size_t);

/*
  int posix_memalign(void** pp, size_t alignment, size_t n);
  Allocates a chunk of n bytes, aligned in accord with the alignment
  argument. Differs from memalign only in that it (1) assigns the
  allocated memory to *pp rather than returning it, (2) fails and
  returns EINVAL if the alignment is not a power of two (3) fails and
  returns ENOMEM if memory cannot be allocated.
*/
DLMALLOC_EXPORT int dlposix_memalign(void**, size_t, size_t);

/*
  valloc(size_t n);
  Equivalent to memalign(pagesize, n), where pagesize is the page
  size of the system. If the pagesize is unknown, 4096 is used.
*/
DLMALLOC_EXPORT void* dlvalloc(size_t);

/*
  mallopt(int parameter_number, int parameter_value)
  Sets 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.  To workaround the fact that mallopt is specified to use int,
  not size_t parameters, the value -1 is specially treated as the
  maximum unsigned size_t value.

  SVID/XPG/ANSI defines four standard param numbers for mallopt,
  normally defined in malloc.h.  None of these are use in this malloc,
  so setting them has no effect. But this malloc also supports other
  options in mallopt. See below for details.  Briefly, supported
  parameters are as follows (listed defaults are for "typical"
  configurations).

  Symbol            param #  default    allowed param values
  M_TRIM_THRESHOLD     -1   2*1024*1024   any   (-1 disables)
  M_GRANULARITY        -2     page size   any power of 2 >= page size
  M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
*/
DLMALLOC_EXPORT int dlmallopt(int, int);

/*
  malloc_footprint();
  Returns the number of bytes obtained from the system.  The total
  number of bytes allocated by malloc, realloc etc., is less than this
  value. Unlike mallinfo, this function returns only a precomputed
  result, so can be called frequently to monitor memory consumption.
  Even if locks are otherwise defined, this function does not use them,
  so results might not be up to date.
*/
DLMALLOC_EXPORT size_t dlmalloc_footprint(void);

/*
  malloc_max_footprint();
  Returns the maximum number of bytes obtained from the system. This
  value will be greater than current footprint if deallocated space
  has been reclaimed by the system. The peak number of bytes allocated
  by malloc, realloc etc., is less than this value. Unlike mallinfo,
  this function returns only a precomputed result, so can be called
  frequently to monitor memory consumption.  Even if locks are
  otherwise defined, this function does not use them, so results might
  not be up to date.
*/
DLMALLOC_EXPORT size_t dlmalloc_max_footprint(void);

/*
  malloc_footprint_limit();
  Returns the number of bytes that the heap is allowed to obtain from
  the system, returning the last value returned by
  malloc_set_footprint_limit, or the maximum size_t value if
  never set. The returned value reflects a permission. There is no
  guarantee that this number of bytes can actually be obtained from
  the system.
*/
DLMALLOC_EXPORT size_t dlmalloc_footprint_limit();

/*
  malloc_set_footprint_limit();
  Sets the maximum number of bytes to obtain from the system, causing
  failure returns from malloc and related functions upon attempts to
  exceed this value. The argument value may be subject to page
  rounding to an enforceable limit; this actual value is returned.
  Using an argument of the maximum possible size_t effectively
  disables checks. If the argument is less than or equal to the
  current malloc_footprint, then all future allocations that require
  additional system memory will fail. However, invocation cannot
  retroactively deallocate existing used memory.
*/
DLMALLOC_EXPORT size_t dlmalloc_set_footprint_limit(size_t bytes);

#if MALLOC_INSPECT_ALL
/*
  malloc_inspect_all(void(*handler)(void *start,
                                    void *end,
                                    size_t used_bytes,
                                    void* callback_arg),
                      void* arg);
  Traverses the heap and calls the given handler for each managed
  region, skipping all bytes that are (or may be) used for bookkeeping
  purposes.  Traversal does not include include chunks that have been
  directly memory mapped. Each reported region begins at the start
  address, and continues up to but not including the end address.  The
  first used_bytes of the region contain allocated data. If
  used_bytes is zero, the region is unallocated. The handler is
  invoked with the given callback argument. If locks are defined, they
  are held during the entire traversal. It is a bad idea to invoke
  other malloc functions from within the handler.

  For example, to count the number of in-use chunks with size greater
  than 1000, you could write:
  static int count = 0;
  void count_chunks(void* start, void* end, size_t used, void* arg) {
    if (used >= 1000) ++count;
  }
  then:
    malloc_inspect_all(count_chunks, NULL);

  malloc_inspect_all is compiled only if MALLOC_INSPECT_ALL is defined.
*/
DLMALLOC_EXPORT void dlmalloc_inspect_all(void(*handler)(void*, void *, size_t, void*),
                           void* arg);

#endif /* MALLOC_INSPECT_ALL */

/*
  mallinfo()
  Returns (by copy) a struct containing various summary statistics:

  arena:     current total non-mmapped bytes allocated from system
  ordblks:   the number of free chunks
  smblks:    always zero.
  hblks:     current number of mmapped regions
  hblkhd:    total bytes held in mmapped regions
  usmblks:   the maximum total allocated space. This will be greater
                than current total if trimming has occurred.
  fsmblks:   always zero
  uordblks:  current total allocated space (normal or mmapped)
  fordblks:  total free space
  keepcost:  the maximum number of bytes that could ideally be released
               back to system via malloc_trim. ("ideally" means that
               it ignores page restrictions etc.)

  Because these fields are ints, but internal bookkeeping may
  be kept as longs, the reported values may wrap around zero and
  thus be inaccurate.
*/
DLMALLOC_EXPORT struct mallinfo dlmallinfo(void);

/*
  independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);

  independent_calloc is similar to calloc, but instead of returning a
  single cleared space, it returns an array of pointers to n_elements
  independent elements that can hold contents of size elem_size, each
  of which starts out cleared, and can be independently freed,
  realloc'ed etc. The elements are guaranteed to be adjacently
  allocated (this is not guaranteed to occur with multiple callocs or
  mallocs), which may also improve cache locality in some
  applications.

  The "chunks" argument is optional (i.e., may be null, which is
  probably the most typical usage). If it is null, the returned array
  is itself dynamically allocated and should also be freed when it is
  no longer needed. Otherwise, the chunks array must be of at least
  n_elements in length. It is filled in with the pointers to the
  chunks.

  In either case, independent_calloc returns this pointer array, or
  null if the allocation failed.  If n_elements is zero and "chunks"
  is null, it returns a chunk representing an array with zero elements
  (which should be freed if not wanted).

  Each element must be freed when it is no longer needed. This can be
  done all at once using bulk_free.

  independent_calloc simplifies and speeds up implementations of many
  kinds of pools.  It may also be useful when constructing large data
  structures that initially have a fixed number of fixed-sized nodes,
  but the number is not known at compile time, and some of the nodes
  may later need to be freed. For example:

  struct Node { int item; struct Node* next; };

  struct Node* build_list() {
    struct Node** pool;
    int n = read_number_of_nodes_needed();
    if (n <= 0) return 0;
    pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
    if (pool == 0) die();
    // organize into a linked list...
    struct Node* first = pool[0];
    for (i = 0; i < n-1; ++i)
      pool[i]->next = pool[i+1];
    free(pool);     // Can now free the array (or not, if it is needed later)
    return first;
  }
*/
DLMALLOC_EXPORT void** dlindependent_calloc(size_t, size_t, void**);

/*
  independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);

  independent_comalloc allocates, all at once, a set of n_elements
  chunks with sizes indicated in the "sizes" array.    It returns
  an array of pointers to these elements, each of which can be
  independently freed, realloc'ed etc. The elements are guaranteed to
  be adjacently allocated (this is not guaranteed to occur with
  multiple callocs or mallocs), which may also improve cache locality
  in some applications.

  The "chunks" argument is optional (i.e., may be null). If it is null
  the returned array is itself dynamically allocated and should also
  be freed when it is no longer needed. Otherwise, the chunks array
  must be of at least n_elements in length. It is filled in with the
  pointers to the chunks.

  In either case, independent_comalloc returns this pointer array, or
  null if the allocation failed.  If n_elements is zero and chunks is
  null, it returns a chunk representing an array with zero elements
  (which should be freed if not wanted).

  Each element must be freed when it is no longer needed. This can be
  done all at once using bulk_free.

  independent_comallac differs from independent_calloc in that each
  element may have a different size, and also that it does not
  automatically clear elements.

  independent_comalloc can be used to speed up allocation in cases
  where several structs or objects must always be allocated at the
  same time.  For example:

  struct Head { ... }
  struct Foot { ... }

  void send_message(char* msg) {
    int msglen = strlen(msg);
    size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
    void* chunks[3];
    if (independent_comalloc(3, sizes, chunks) == 0)
      die();
    struct Head* head = (struct Head*)(chunks[0]);
    char*        body = (char*)(chunks[1]);
    struct Foot* foot = (struct Foot*)(chunks[2]);
    // ...
  }

  In general though, independent_comalloc is worth using only for
  larger values of n_elements. For small values, you probably won't
  detect enough difference from series of malloc calls to bother.

  Overuse of independent_comalloc can increase overall memory usage,
  since it cannot reuse existing noncontiguous small chunks that
  might be available for some of the elements.
*/
DLMALLOC_EXPORT void** dlindependent_comalloc(size_t, size_t*, void**);

/*
  bulk_free(void* array[], size_t n_elements)
  Frees and clears (sets to null) each non-null pointer in the given
  array.  This is likely to be faster than freeing them one-by-one.
  If footers are used, pointers that have been allocated in different
  mspaces are not freed or cleared, and the count of all such pointers
  is returned.  For large arrays of pointers with poor locality, it
  may be worthwhile to sort this array before calling bulk_free.
*/
DLMALLOC_EXPORT size_t  dlbulk_free(void**, size_t n_elements);

/*
  pvalloc(size_t n);
  Equivalent to valloc(minimum-page-that-holds(n)), that is,
  round up n to nearest pagesize.
 */
DLMALLOC_EXPORT void*  dlpvalloc(size_t);

/*
  malloc_trim(size_t pad);

  If possible, gives memory back to the system (via negative arguments
  to sbrk) if there is unused memory at the `high' end of the malloc
  pool or in unused MMAP segments. 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. 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.
*/
DLMALLOC_EXPORT int  dlmalloc_trim(size_t);

/*
  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.
*/
DLMALLOC_EXPORT void  dlmalloc_stats(void);

/*
  malloc_usable_size(void* p);

  Returns the number of bytes you can actually use in
  an allocated chunk, which may be more than you requested (although
  often not) due to alignment and minimum size constraints.
  You can use this many bytes without worrying about
  overwriting other allocated objects. This is not a particularly great
  programming practice. malloc_usable_size can be more useful in
  debugging and assertions, for example:

  p = malloc(n);
  assert(malloc_usable_size(p) >= 256);
*/
size_t dlmalloc_usable_size(void*);

#endif /* ONLY_MSPACES */

#if MSPACES

/*
  mspace is an opaque type representing an independent
  region of space that supports mspace_malloc, etc.
*/
typedef void* mspace;

/*
  create_mspace creates and returns a new independent space with the
  given initial capacity, or, if 0, the default granularity size.  It
  returns null if there is no system memory available to create the
  space.  If argument locked is non-zero, the space uses a separate
  lock to control access. The capacity of the space will grow
  dynamically as needed to service mspace_malloc requests.  You can
  control the sizes of incremental increases of this space by
  compiling with a different DEFAULT_GRANULARITY or dynamically
  setting with mallopt(M_GRANULARITY, value).
*/
DLMALLOC_EXPORT mspace create_mspace(size_t capacity, int locked);

/*
  destroy_mspace destroys the given space, and attempts to return all
  of its memory back to the system, returning the total number of
  bytes freed. After destruction, the results of access to all memory
  used by the space become undefined.
*/
DLMALLOC_EXPORT size_t destroy_mspace(mspace msp);

/*
  create_mspace_with_base uses the memory supplied as the initial base
  of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
  space is used for bookkeeping, so the capacity must be at least this
  large. (Otherwise 0 is returned.) When this initial space is
  exhausted, additional memory will be obtained from the system.
  Destroying this space will deallocate all additionally allocated
  space (if possible) but not the initial base.
*/
DLMALLOC_EXPORT mspace create_mspace_with_base(void* base, size_t capacity, int locked);

/*
  mspace_track_large_chunks controls whether requests for large chunks
  are allocated in their own untracked mmapped regions, separate from
  others in this mspace. By default large chunks are not tracked,
  which reduces fragmentation. However, such chunks are not
  necessarily released to the system upon destroy_mspace.  Enabling
  tracking by setting to true may increase fragmentation, but avoids
  leakage when relying on destroy_mspace to release all memory
  allocated using this space.  The function returns the previous
  setting.
*/
DLMALLOC_EXPORT int mspace_track_large_chunks(mspace msp, int enable);


/*
  mspace_malloc behaves as malloc, but operates within
  the given space.
*/
DLMALLOC_EXPORT void* mspace_malloc(mspace msp, size_t bytes);

/*
  mspace_free behaves as free, but operates within
  the given space.

  If compiled with FOOTERS==1, mspace_free is not actually needed.
  free may be called instead of mspace_free because freed chunks from
  any space are handled by their originating spaces.
*/
DLMALLOC_EXPORT void mspace_free(mspace msp, void* mem);

/*
  mspace_realloc behaves as realloc, but operates within
  the given space.

  If compiled with FOOTERS==1, mspace_realloc is not actually
  needed.  realloc may be called instead of mspace_realloc because
  realloced chunks from any space are handled by their originating
  spaces.
*/
DLMALLOC_EXPORT void* mspace_realloc(mspace msp, void* mem, size_t newsize);

/*
  mspace_calloc behaves as calloc, but operates within
  the given space.
*/
DLMALLOC_EXPORT void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);

/*
  mspace_memalign behaves as memalign, but operates within
  the given space.
*/
DLMALLOC_EXPORT void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);

/*
  mspace_independent_calloc behaves as independent_calloc, but
  operates within the given space.
*/
DLMALLOC_EXPORT void** mspace_independent_calloc(mspace msp, size_t n_elements,
                                 size_t elem_size, void* chunks[]);

/*
  mspace_independent_comalloc behaves as independent_comalloc, but
  operates within the given space.
*/
DLMALLOC_EXPORT void** mspace_independent_comalloc(mspace msp, size_t n_elements,
                                   size_t sizes[], void* chunks[]);

/*
  mspace_footprint() returns the number of bytes obtained from the
  system for this space.
*/
DLMALLOC_EXPORT size_t mspace_footprint(mspace msp);

/*
  mspace_max_footprint() returns the peak number of bytes obtained from the
  system for this space.
*/
DLMALLOC_EXPORT size_t mspace_max_footprint(mspace msp);


#if !NO_MALLINFO
/*
  mspace_mallinfo behaves as mallinfo, but reports properties of
  the given space.
*/
DLMALLOC_EXPORT struct mallinfo mspace_mallinfo(mspace msp);
#endif /* NO_MALLINFO */

/*
  malloc_usable_size(void* p) behaves the same as malloc_usable_size;
*/
DLMALLOC_EXPORT size_t mspace_usable_size(const void* mem);

/*
  mspace_malloc_stats behaves as malloc_stats, but reports
  properties of the given space.
*/
DLMALLOC_EXPORT void mspace_malloc_stats(mspace msp);

/*
  mspace_trim behaves as malloc_trim, but
  operates within the given space.
*/
DLMALLOC_EXPORT int mspace_trim(mspace msp, size_t pad);

/*
  An alias for mallopt.
*/
DLMALLOC_EXPORT int mspace_mallopt(int, int);

#endif /* MSPACES */

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

/*
  ========================================================================
  To make a fully customizable malloc.h header file, cut everything
  above this line, put into file malloc.h, edit to suit, and #include it
  on the next line, as well as in programs that use this malloc.
  ========================================================================
*/

/* #include "malloc.h" */

/*------------------------------ internal #includes ---------------------- */

#ifdef _MSC_VER
#pragma warning( disable : 4146 ) /* no "unsigned" warnings */
#endif /* _MSC_VER */
#if !NO_MALLOC_STATS
#endif /* NO_MALLOC_STATS */
#ifndef LACKS_ERRNO_H
#include <errno.h>       /* for MALLOC_FAILURE_ACTION */
#endif /* LACKS_ERRNO_H */
#ifdef DEBUG
#if ABORT_ON_ASSERT_FAILURE
#undef assert
#define assert(x) if(!(x)) ABORT
#else /* ABORT_ON_ASSERT_FAILURE */
#include <assert.h>
#endif /* ABORT_ON_ASSERT_FAILURE */
#else  /* DEBUG */
#ifndef assert
#define assert(x)
#endif
#define DEBUG 0
#endif /* DEBUG */
#if !defined(WIN32) && !defined(LACKS_TIME_H)
#include <time.h>        /* for magic initialization */
#endif /* WIN32 */
#ifndef LACKS_STDLIB_H
#include <stdlib.h>      /* for abort() */
#endif /* LACKS_STDLIB_H */
#ifndef LACKS_STRING_H
#include <string.h>      /* for memset etc */
#endif  /* LACKS_STRING_H */
#if USE_BUILTIN_FFS
#ifndef LACKS_STRINGS_H
#include <strings.h>     /* for ffs */
#endif /* LACKS_STRINGS_H */
#endif /* USE_BUILTIN_FFS */
#if HAVE_MMAP
#ifndef LACKS_SYS_MMAN_H
/* On some versions of linux, mremap decl in mman.h needs __USE_GNU set */
#if (defined(linux) && !defined(__USE_GNU))
#define __USE_GNU 1
#include <sys/mman.h>    /* for mmap */
#undef __USE_GNU
#else
#include <sys/mman.h>    /* for mmap */
#endif /* linux */
#endif /* LACKS_SYS_MMAN_H */
#ifndef LACKS_FCNTL_H
#include <fcntl.h>
#endif /* LACKS_FCNTL_H */
#endif /* HAVE_MMAP */
#ifndef LACKS_UNISTD_H
#include <unistd.h>     /* for sbrk, sysconf */
#else /* LACKS_UNISTD_H */
#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__COSMOPOLITAN__)
extern void*     sbrk(ptrdiff_t);
#endif /* FreeBSD etc */
#endif /* LACKS_UNISTD_H */

/* Declarations for locking */
#if USE_LOCKS
#ifndef WIN32
#if defined (__SVR4) && defined (__sun)  /* solaris */
#include <thread.h>
#elif !defined(LACKS_SCHED_H)
#include <sched.h>
#endif /* solaris or LACKS_SCHED_H */
#if (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0) || !USE_SPIN_LOCKS
#include <pthread.h>
#endif /* USE_RECURSIVE_LOCKS ... */
#elif defined(_MSC_VER)
#ifndef _M_AMD64
/* These are already defined on AMD64 builds */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
LONG __cdecl _InterlockedCompareExchange(LONG volatile *Dest, LONG Exchange, LONG Comp);
LONG __cdecl _InterlockedExchange(LONG volatile *Target, LONG Value);
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _M_AMD64 */
#pragma intrinsic (_InterlockedCompareExchange)
#pragma intrinsic (_InterlockedExchange)
#define interlockedcompareexchange _InterlockedCompareExchange
#define interlockedexchange _InterlockedExchange
#elif defined(WIN32) && defined(__GNUC__)
#define interlockedcompareexchange(a, b, c) __sync_val_compare_and_swap(a, c, b)
#define interlockedexchange __sync_lock_test_and_set
#endif /* Win32 */
#else /* USE_LOCKS */
#endif /* USE_LOCKS */

#ifndef LOCK_AT_FORK
#define LOCK_AT_FORK 0
#endif

/* Declarations for bit scanning on win32 */
#if defined(_MSC_VER) && _MSC_VER>=1300
#ifndef BitScanForward /* Try to avoid pulling in WinNT.h */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
unsigned char _BitScanForward(unsigned long *index, unsigned long mask);
unsigned char _BitScanReverse(unsigned long *index, unsigned long mask);
#ifdef __cplusplus
}
#endif /* __cplusplus */

#define BitScanForward _BitScanForward
#define BitScanReverse _BitScanReverse
#pragma intrinsic(_BitScanForward)
#pragma intrinsic(_BitScanReverse)
#endif /* BitScanForward */
#endif /* defined(_MSC_VER) && _MSC_VER>=1300 */

#ifndef WIN32
#ifndef malloc_getpagesize
#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
#    ifndef _SC_PAGE_SIZE
#      define _SC_PAGE_SIZE _SC_PAGESIZE
#    endif
#  endif
#  ifdef _SC_PAGE_SIZE
#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
#  else
#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
       extern size_t getpagesize();
#      define malloc_getpagesize getpagesize()
#    else
#      ifdef WIN32 /* 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 ((size_t)4096U)
#              endif
#            endif
#          endif
#        endif
#      endif
#    endif
#  endif
#endif
#endif

/* ------------------- size_t and alignment properties -------------------- */

/* The byte and bit size of a size_t */
#define SIZE_T_SIZE         (sizeof(size_t))
#define SIZE_T_BITSIZE      (sizeof(size_t) << 3)

/* Some constants coerced to size_t */
/* Annoying but necessary to avoid errors on some platforms */
#define SIZE_T_ZERO         ((size_t)0)
#define SIZE_T_ONE          ((size_t)1)
#define SIZE_T_TWO          ((size_t)2)
#define SIZE_T_FOUR         ((size_t)4)
#define TWO_SIZE_T_SIZES    (SIZE_T_SIZE<<1)
#define FOUR_SIZE_T_SIZES   (SIZE_T_SIZE<<2)
#define SIX_SIZE_T_SIZES    (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
#define HALF_MAX_SIZE_T     (MAX_SIZE_T / 2U)

/* The bit mask value corresponding to MALLOC_ALIGNMENT */
#define CHUNK_ALIGN_MASK    (MALLOC_ALIGNMENT - SIZE_T_ONE)

/* True if address a has acceptable alignment */
#define is_aligned(A)       (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)

/* the number of bytes to offset an address to align it */
#define align_offset(A)\
 ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
  ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))

/* -------------------------- MMAP preliminaries ------------------------- */

/*
   If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
   checks to fail so compiler optimizer can delete code rather than
   using so many "#if"s.
*/


/* MORECORE and MMAP must return MFAIL on failure */
#define MFAIL                ((void*)(MAX_SIZE_T))
#define CMFAIL               ((char*)(MFAIL)) /* defined for convenience */

#if HAVE_MMAP

#ifndef WIN32
#define MUNMAP_DEFAULT(a, s)  munmap((a), (s))
#define MMAP_PROT            (PROT_READ|PROT_WRITE)
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS        MAP_ANON
#endif /* MAP_ANON */
#ifdef MAP_ANONYMOUS
#define MMAP_FLAGS           (MAP_PRIVATE|MAP_ANONYMOUS)
#define MMAP_DEFAULT(s)       mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
#else /* MAP_ANONYMOUS */
/*
   Nearly all versions of mmap support MAP_ANONYMOUS, so the following
   is unlikely to be needed, but is supplied just in case.
*/
#define MMAP_FLAGS           (MAP_PRIVATE)
static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
#define MMAP_DEFAULT(s) ((dev_zero_fd < 0) ? \
           (dev_zero_fd = open("/dev/zero", O_RDWR), \
            mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
            mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
#endif /* MAP_ANONYMOUS */

#define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s)

#else /* WIN32 */

/* Win32 MMAP via VirtualAlloc */
FORCEINLINE void* win32mmap(size_t size) {
  void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
  return (ptr != 0)? ptr: MFAIL;
}

/* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
FORCEINLINE void* win32direct_mmap(size_t size) {
  void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN,
                           PAGE_READWRITE);
  return (ptr != 0)? ptr: MFAIL;
}

/* This function supports releasing coalesed segments */
FORCEINLINE int win32munmap(void* ptr, size_t size) {
  MEMORY_BASIC_INFORMATION minfo;
  char* cptr = (char*)ptr;
  while (size) {
    if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
      return -1;
    if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
        minfo.State != MEM_COMMIT || minfo.RegionSize > size)
      return -1;
    if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
      return -1;
    cptr += minfo.RegionSize;
    size -= minfo.RegionSize;
  }
  return 0;
}

#define MMAP_DEFAULT(s)             win32mmap(s)
#define MUNMAP_DEFAULT(a, s)        win32munmap((a), (s))
#define DIRECT_MMAP_DEFAULT(s)      win32direct_mmap(s)
#endif /* WIN32 */
#endif /* HAVE_MMAP */

#if HAVE_MREMAP
#ifndef WIN32
#define MREMAP_DEFAULT(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
#endif /* WIN32 */
#endif /* HAVE_MREMAP */

/**
 * Define CALL_MORECORE
 */
#if HAVE_MORECORE
    #ifdef MORECORE
        #define CALL_MORECORE(S)    MORECORE(S)
    #else  /* MORECORE */
        #define CALL_MORECORE(S)    MORECORE_DEFAULT(S)
    #endif /* MORECORE */
#else  /* HAVE_MORECORE */
    #define CALL_MORECORE(S)        MFAIL
#endif /* HAVE_MORECORE */

/**
 * Define CALL_MMAP/CALL_MUNMAP/CALL_DIRECT_MMAP
 */
#if HAVE_MMAP
    #define USE_MMAP_BIT            (SIZE_T_ONE)

    #ifdef MMAP
        #define CALL_MMAP(s)        MMAP(s)
    #else /* MMAP */
        #define CALL_MMAP(s)        MMAP_DEFAULT(s)
    #endif /* MMAP */
    #ifdef MUNMAP
        #define CALL_MUNMAP(a, s)   MUNMAP((a), (s))
    #else /* MUNMAP */
        #define CALL_MUNMAP(a, s)   MUNMAP_DEFAULT((a), (s))
    #endif /* MUNMAP */
    #ifdef DIRECT_MMAP
        #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s)
    #else /* DIRECT_MMAP */
        #define CALL_DIRECT_MMAP(s) DIRECT_MMAP_DEFAULT(s)
    #endif /* DIRECT_MMAP */
#else  /* HAVE_MMAP */
    #define USE_MMAP_BIT            (SIZE_T_ZERO)

    #define MMAP(s)                 MFAIL
    #define MUNMAP(a, s)            (-1)
    #define DIRECT_MMAP(s)          MFAIL
    #define CALL_DIRECT_MMAP(s)     DIRECT_MMAP(s)
    #define CALL_MMAP(s)            MMAP(s)
    #define CALL_MUNMAP(a, s)       MUNMAP((a), (s))
#endif /* HAVE_MMAP */

/**
 * Define CALL_MREMAP
 */
#if HAVE_MMAP && HAVE_MREMAP
    #ifdef MREMAP
        #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP((addr), (osz), (nsz), (mv))
    #else /* MREMAP */
        #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP_DEFAULT((addr), (osz), (nsz), (mv))
    #endif /* MREMAP */
#else  /* HAVE_MMAP && HAVE_MREMAP */
    #define CALL_MREMAP(addr, osz, nsz, mv)     MFAIL
#endif /* HAVE_MMAP && HAVE_MREMAP */

/* mstate bit set if continguous morecore disabled or failed */
#define USE_NONCONTIGUOUS_BIT (4U)

/* segment bit set in create_mspace_with_base */
#define EXTERN_BIT            (8U)


/* --------------------------- Lock preliminaries ------------------------ */

/*
  When locks are defined, there is one global lock, plus
  one per-mspace lock.

  The global lock_ensures that mparams.magic and other unique
  mparams values are initialized only once. It also protects
  sequences of calls to MORECORE.  In many cases sys_alloc requires
  two calls, that should not be interleaved with calls by other
  threads.  This does not protect against direct calls to MORECORE
  by other threads not using this lock, so there is still code to
  cope the best we can on interference.

  Per-mspace locks surround calls to malloc, free, etc.
  By default, locks are simple non-reentrant mutexes.

  Because lock-protected regions generally have bounded times, it is
  OK to use the supplied simple spinlocks. Spinlocks are likely to
  improve performance for lightly contended applications, but worsen
  performance under heavy contention.

  If USE_LOCKS is > 1, the definitions of lock routines here are
  bypassed, in which case you will need to define the type MLOCK_T,
  and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK
  and TRY_LOCK.  You must also declare a
    static MLOCK_T malloc_global_mutex = { initialization values };.

*/

#if !USE_LOCKS
#define USE_LOCK_BIT               (0U)
#define INITIAL_LOCK(l)            (0)
#define DESTROY_LOCK(l)            (0)
#define ACQUIRE_MALLOC_GLOBAL_LOCK()
#define RELEASE_MALLOC_GLOBAL_LOCK()

#else
#if USE_LOCKS > 1
/* -----------------------  User-defined locks ------------------------ */
/* Define your own lock implementation here */
/* #define INITIAL_LOCK(lk)  ... */
/* #define DESTROY_LOCK(lk)  ... */
/* #define ACQUIRE_LOCK(lk)  ... */
/* #define RELEASE_LOCK(lk)  ... */
/* #define TRY_LOCK(lk) ... */
/* static MLOCK_T malloc_global_mutex = ... */

#elif USE_SPIN_LOCKS

/* First, define CAS_LOCK and CLEAR_LOCK on ints */
/* Note CAS_LOCK defined to return 0 on success */

#if defined(__GNUC__)&& (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
#define CAS_LOCK(sl)     __sync_lock_test_and_set(sl, 1)
#define CLEAR_LOCK(sl)   __sync_lock_release(sl)

#elif (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
/* Custom spin locks for older gcc on x86 */
FORCEINLINE int x86_cas_lock(int *sl) {
  int ret;
  int val = 1;
  int cmp = 0;
  __asm__ __volatile__  ("lock; cmpxchgl %1, %2"
                         : "=a" (ret)
                         : "r" (val), "m" (*(sl)), "0"(cmp)
                         : "memory", "cc");
  return ret;
}

FORCEINLINE void x86_clear_lock(int* sl) {
  assert(*sl != 0);
  int prev = 0;
  int ret;
  __asm__ __volatile__ ("lock; xchgl %0, %1"
                        : "=r" (ret)
                        : "m" (*(sl)), "0"(prev)
                        : "memory");
}

#define CAS_LOCK(sl)     x86_cas_lock(sl)
#define CLEAR_LOCK(sl)   x86_clear_lock(sl)

#else /* Win32 MSC */
#define CAS_LOCK(sl)     interlockedexchange(sl, (LONG)1)
#define CLEAR_LOCK(sl)   interlockedexchange (sl, (LONG)0)

#endif /* ... gcc spins locks ... */

#if !defined(USE_RECURSIVE_LOCKS) || USE_RECURSIVE_LOCKS == 0
/* Plain spin locks use single word (embedded in malloc_states) */
static dontinline int spin_acquire_lock(int *sl) {
  while (*(volatile int *)sl != 0 || CAS_LOCK(sl)) {
    __builtin_ia32_pause();
  }
  return 0;
}

#define MLOCK_T               int
#define TRY_LOCK(sl)          !CAS_LOCK(sl)
#define RELEASE_LOCK(sl)      CLEAR_LOCK(sl)
#define ACQUIRE_LOCK(sl)      (CAS_LOCK(sl)? spin_acquire_lock(sl) : 0)
#define INITIAL_LOCK(sl)      (*sl = 0)
#define DESTROY_LOCK(sl)      (0)
static MLOCK_T malloc_global_mutex = 0;

#else /* USE_RECURSIVE_LOCKS */
/* types for lock owners */
#ifdef WIN32
#define THREAD_ID_T           DWORD
#define CURRENT_THREAD        GetCurrentThreadId()
#define EQ_OWNER(X,Y)         ((X) == (Y))
#else
/*
  Note: the following assume that pthread_t is a type that can be
  initialized to (casted) zero. If this is not the case, you will need to
  somehow redefine these or not use spin locks.
*/
#define THREAD_ID_T           pthread_t
#define CURRENT_THREAD        pthread_self()
#define EQ_OWNER(X,Y)         pthread_equal(X, Y)
#endif

struct malloc_recursive_lock {
  int sl;
  unsigned int c;
  THREAD_ID_T threadid;
};

#define MLOCK_T  struct malloc_recursive_lock
static MLOCK_T malloc_global_mutex = { 0, 0, (THREAD_ID_T)0};

FORCEINLINE void recursive_release_lock(MLOCK_T *lk) {
  assert(lk->sl != 0);
  if (--lk->c == 0) {
    CLEAR_LOCK(&lk->sl);
  }
}

FORCEINLINE int recursive_acquire_lock(MLOCK_T *lk) {
  THREAD_ID_T mythreadid = CURRENT_THREAD;
  for (;;) {
    if (*((volatile int *)(&lk->sl)) == 0) {
      if (!CAS_LOCK(&lk->sl)) {
        lk->threadid = mythreadid;
        lk->c = 1;
        return 0;
      }
    }
    else if (EQ_OWNER(lk->threadid, mythreadid)) {
      ++lk->c;
      return 0;
    }
    __builtin_ia32_pause();
  }
}

FORCEINLINE int recursive_try_lock(MLOCK_T *lk) {
  THREAD_ID_T mythreadid = CURRENT_THREAD;
  if (*((volatile int *)(&lk->sl)) == 0) {
    if (!CAS_LOCK(&lk->sl)) {
      lk->threadid = mythreadid;
      lk->c = 1;
      return 1;
    }
  }
  else if (EQ_OWNER(lk->threadid, mythreadid)) {
    ++lk->c;
    return 1;
  }
  return 0;
}

#define RELEASE_LOCK(lk)      recursive_release_lock(lk)
#define TRY_LOCK(lk)          recursive_try_lock(lk)
#define ACQUIRE_LOCK(lk)      recursive_acquire_lock(lk)
#define INITIAL_LOCK(lk)      ((lk)->threadid = (THREAD_ID_T)0, (lk)->sl = 0, (lk)->c = 0)
#define DESTROY_LOCK(lk)      (0)
#endif /* USE_RECURSIVE_LOCKS */

#elif defined(WIN32) /* Win32 critical sections */
#define MLOCK_T               CRITICAL_SECTION
#define ACQUIRE_LOCK(lk)      (EnterCriticalSection(lk), 0)
#define RELEASE_LOCK(lk)      LeaveCriticalSection(lk)
#define TRY_LOCK(lk)          TryEnterCriticalSection(lk)
#define INITIAL_LOCK(lk)      (!InitializeCriticalSectionAndSpinCount((lk), 0x80000000|4000))
#define DESTROY_LOCK(lk)      (DeleteCriticalSection(lk), 0)
#define NEED_GLOBAL_LOCK_INIT

static MLOCK_T malloc_global_mutex;
static volatile LONG malloc_global_mutex_status;

/* Use spin loop to initialize global lock */
static void init_malloc_global_mutex() {
  for (;;) {
    long stat = malloc_global_mutex_status;
    if (stat > 0)
      return;
    /* transition to < 0 while initializing, then to > 0) */
    if (stat == 0 &&
        interlockedcompareexchange(&malloc_global_mutex_status, (LONG)-1, (LONG)0) == 0) {
      InitializeCriticalSection(&malloc_global_mutex);
      interlockedexchange(&malloc_global_mutex_status, (LONG)1);
      return;
    }
    SleepEx(0, FALSE);
  }
}

#else /* pthreads-based locks */
#define MLOCK_T               pthread_mutex_t
#define ACQUIRE_LOCK(lk)      pthread_mutex_lock(lk)
#define RELEASE_LOCK(lk)      pthread_mutex_unlock(lk)
#define TRY_LOCK(lk)          (!pthread_mutex_trylock(lk))
#define INITIAL_LOCK(lk)      pthread_init_lock(lk)
#define DESTROY_LOCK(lk)      pthread_mutex_destroy(lk)

#if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0 && defined(linux) && !defined(PTHREAD_MUTEX_RECURSIVE)
/* Cope with old-style linux recursive lock initialization by adding */
/* skipped internal declaration from pthread.h */
extern int pthread_mutexattr_setkind_np __P ((pthread_mutexattr_t *__attr,
                                              int __kind));
#define PTHREAD_MUTEX_RECURSIVE PTHREAD_MUTEX_RECURSIVE_NP
#define pthread_mutexattr_settype(x,y) pthread_mutexattr_setkind_np(x,y)
#endif /* USE_RECURSIVE_LOCKS ... */

static MLOCK_T malloc_global_mutex = PTHREAD_MUTEX_INITIALIZER;

static int pthread_init_lock (MLOCK_T *lk) {
  pthread_mutexattr_t attr;
  if (pthread_mutexattr_init(&attr)) return 1;
#if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0
  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) return 1;
#endif
  if (pthread_mutex_init(lk, &attr)) return 1;
  if (pthread_mutexattr_destroy(&attr)) return 1;
  return 0;
}

#endif /* ... lock types ... */

/* Common code for all lock types */
#define USE_LOCK_BIT               (2U)

#ifndef ACQUIRE_MALLOC_GLOBAL_LOCK
#define ACQUIRE_MALLOC_GLOBAL_LOCK()  ACQUIRE_LOCK(&malloc_global_mutex);
#endif

#ifndef RELEASE_MALLOC_GLOBAL_LOCK
#define RELEASE_MALLOC_GLOBAL_LOCK()  RELEASE_LOCK(&malloc_global_mutex);
#endif

#endif /* USE_LOCKS */

struct malloc_chunk {
  size_t               prev_foot;  /* Size of previous chunk (if free).  */
  size_t               head;       /* Size and inuse bits. */
  struct malloc_chunk* fd;         /* double links -- used only if free. */
  struct malloc_chunk* bk;
};

typedef struct malloc_chunk  mchunk;
typedef struct malloc_chunk* mchunkptr;
typedef struct malloc_chunk* sbinptr;  /* The type of bins of chunks */
typedef unsigned int bindex_t;         /* Described below */
typedef unsigned int binmap_t;         /* Described below */
typedef unsigned int flag_t;           /* The type of various bit flag sets */

/* ------------------- Chunks sizes and alignments ----------------------- */

#define MCHUNK_SIZE         (sizeof(mchunk))

#if FOOTERS
#define CHUNK_OVERHEAD      (TWO_SIZE_T_SIZES)
#else /* FOOTERS */
#define CHUNK_OVERHEAD      (SIZE_T_SIZE)
#endif /* FOOTERS */

/* MMapped chunks need a second word of overhead ... */
#define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
/* ... and additional padding for fake next-chunk at foot */
#define MMAP_FOOT_PAD       (FOUR_SIZE_T_SIZES)

/* The smallest size we can malloc is an aligned minimal chunk */
#define MIN_CHUNK_SIZE\
  ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)

/* conversion from malloc headers to user pointers, and back */
#define chunk2mem(p)        ((void*)((char*)(p)       + TWO_SIZE_T_SIZES))
#define mem2chunk(mem)      ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
/* chunk associated with aligned address A */
#define align_as_chunk(A)   (mchunkptr)((A) + align_offset(chunk2mem(A)))

/* Bounds on request (not chunk) sizes. */
#define MAX_REQUEST         ((-MIN_CHUNK_SIZE) << 2)
#define MIN_REQUEST         (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)

/* pad request bytes into a usable size */
#define pad_request(req) \
   (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)

/* pad request, checking for minimum (but not maximum) */
#define request2size(req) \
  (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))


/* ------------------ Operations on head and foot fields ----------------- */

/*
  The head field of a chunk is or'ed with PINUSE_BIT when previous
  adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
  use, unless mmapped, in which case both bits are cleared.

  FLAG4_BIT is not used by this malloc, but might be useful in extensions.
*/

#define PINUSE_BIT          (SIZE_T_ONE)
#define CINUSE_BIT          (SIZE_T_TWO)
#define FLAG4_BIT           (SIZE_T_FOUR)
#define INUSE_BITS          (PINUSE_BIT|CINUSE_BIT)
#define FLAG_BITS           (PINUSE_BIT|CINUSE_BIT|FLAG4_BIT)

/* Head value for fenceposts */
#define FENCEPOST_HEAD      (INUSE_BITS|SIZE_T_SIZE)

/* extraction of fields from head words */
#define cinuse(p)           ((p)->head & CINUSE_BIT)
#define pinuse(p)           ((p)->head & PINUSE_BIT)
#define flag4inuse(p)       ((p)->head & FLAG4_BIT)
#define is_inuse(p)         (((p)->head & INUSE_BITS) != PINUSE_BIT)
#define is_mmapped(p)       (((p)->head & INUSE_BITS) == 0)

#define chunksize(p)        ((p)->head & ~(FLAG_BITS))

#define clear_pinuse(p)     ((p)->head &= ~PINUSE_BIT)
#define set_flag4(p)        ((p)->head |= FLAG4_BIT)
#define clear_flag4(p)      ((p)->head &= ~FLAG4_BIT)

/* Treat space at ptr +/- offset as a chunk */
#define chunk_plus_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
#define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))

/* Ptr to next or previous physical malloc_chunk. */
#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~FLAG_BITS)))
#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))

/* extract next chunk's pinuse bit */
#define next_pinuse(p)  ((next_chunk(p)->head) & PINUSE_BIT)

/* Get/set size at footer */
#define get_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot)
#define set_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))

/* Set size, pinuse bit, and foot */
#define set_size_and_pinuse_of_free_chunk(p, s)\
  ((p)->head = (s|PINUSE_BIT), set_foot(p, s))

/* Set size, pinuse bit, foot, and clear next pinuse */
#define set_free_with_pinuse(p, s, n)\
  (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))

/* Get the internal overhead associated with chunk p */
#define overhead_for(p)\
 (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)

/* Return true if malloced space is not necessarily cleared */
#if MMAP_CLEARS
#define calloc_must_clear(p) (!is_mmapped(p))
#else /* MMAP_CLEARS */
#define calloc_must_clear(p) (1)
#endif /* MMAP_CLEARS */


struct malloc_tree_chunk {
  /* The first four fields must be compatible with malloc_chunk */
  size_t                    prev_foot;
  size_t                    head;
  struct malloc_tree_chunk* fd;
  struct malloc_tree_chunk* bk;

  struct malloc_tree_chunk* child[2];
  struct malloc_tree_chunk* parent;
  bindex_t                  index;
};

typedef struct malloc_tree_chunk  tchunk;
typedef struct malloc_tree_chunk* tchunkptr;
typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */

/* A little helper macro for trees */
#define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])

struct malloc_segment {
  char*        base;             /* base address */
  size_t       size;             /* allocated size */
  struct malloc_segment* next;   /* ptr to next segment */
  flag_t       sflags;           /* mmap and extern flag */
};

#define is_mmapped_segment(S)  ((S)->sflags & USE_MMAP_BIT)
#define is_extern_segment(S)   ((S)->sflags & EXTERN_BIT)

typedef struct malloc_segment  msegment;
typedef struct malloc_segment* msegmentptr;

/* Bin types, widths and sizes */
#define NSMALLBINS        (32U)
#define NTREEBINS         (32U)
#define SMALLBIN_SHIFT    (3U)
#define SMALLBIN_WIDTH    (SIZE_T_ONE << SMALLBIN_SHIFT)
#define TREEBIN_SHIFT     (8U)
#define MIN_LARGE_SIZE    (SIZE_T_ONE << TREEBIN_SHIFT)
#define MAX_SMALL_SIZE    (MIN_LARGE_SIZE - SIZE_T_ONE)
#define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)

struct malloc_state {
  binmap_t   smallmap;
  binmap_t   treemap;
  size_t     dvsize;
  size_t     topsize;
  char*      least_addr;
  mchunkptr  dv;
  mchunkptr  top;
  size_t     trim_check;
  size_t     release_checks;
  size_t     magic;
  mchunkptr  smallbins[(NSMALLBINS+1)*2];
  tbinptr    treebins[NTREEBINS];
  size_t     footprint;
  size_t     max_footprint;
  size_t     footprint_limit; /* zero means no limit */
  flag_t     mflags;
#if USE_LOCKS
  MLOCK_T    mutex;     /* locate lock among fields that rarely change */
#endif /* USE_LOCKS */
  msegment   seg;
  void*      extp;      /* Unused but available for extensions */
  size_t     exts;
};

typedef struct malloc_state*    mstate;

/* ------------- Global malloc_state and malloc_params ------------------- */

/*
  malloc_params holds global properties, including those that can be
  dynamically set using mallopt. There is a single instance, mparams,
  initialized in init_mparams. Note that the non-zeroness of "magic"
  also serves as an initialization flag.
*/

struct malloc_params {
  size_t magic;
  size_t page_size;
  size_t granularity;
  size_t mmap_threshold;
  size_t trim_threshold;
  flag_t default_mflags;
};

static struct malloc_params mparams;

/* Ensure mparams initialized */
#define ensure_initialization() (void)(mparams.magic != 0 || init_mparams())

#if !ONLY_MSPACES

/* The global malloc_state used for all non-"mspace" calls */
static struct malloc_state _gm_;
#define gm                 (&_gm_)
#define is_global(M)       ((M) == &_gm_)

#endif /* !ONLY_MSPACES */

#define is_initialized(M)  ((M)->top != 0)

/* -------------------------- system alloc setup ------------------------- */

/* Operations on mflags */

#define use_lock(M)           ((M)->mflags &   USE_LOCK_BIT)
#define enable_lock(M)        ((M)->mflags |=  USE_LOCK_BIT)
#if USE_LOCKS
#define disable_lock(M)       ((M)->mflags &= ~USE_LOCK_BIT)
#else
#define disable_lock(M)
#endif

#define use_mmap(M)           ((M)->mflags &   USE_MMAP_BIT)
#define enable_mmap(M)        ((M)->mflags |=  USE_MMAP_BIT)
#if HAVE_MMAP
#define disable_mmap(M)       ((M)->mflags &= ~USE_MMAP_BIT)
#else
#define disable_mmap(M)
#endif

#define use_noncontiguous(M)  ((M)->mflags &   USE_NONCONTIGUOUS_BIT)
#define disable_contiguous(M) ((M)->mflags |=  USE_NONCONTIGUOUS_BIT)

#define set_lock(M,L)\
 ((M)->mflags = (L)?\
  ((M)->mflags | USE_LOCK_BIT) :\
  ((M)->mflags & ~USE_LOCK_BIT))

/* page-align a size */
#define page_align(S)\
 (((S) + (mparams.page_size - SIZE_T_ONE)) & ~(mparams.page_size - SIZE_T_ONE))

/* granularity-align a size */
#define granularity_align(S)\
  (((S) + (mparams.granularity - SIZE_T_ONE))\
   & ~(mparams.granularity - SIZE_T_ONE))


/* For mmap, use granularity alignment on windows, else page-align */
#if defined(WIN32) || defined(__COSMOPOLITAN__)
#define mmap_align(S) granularity_align(S)
#else
#define mmap_align(S) page_align(S)
#endif

/* For sys_alloc, enough padding to ensure can malloc request on success */
#define SYS_ALLOC_PADDING (TOP_FOOT_SIZE + MALLOC_ALIGNMENT)

#define is_page_aligned(S)\
   (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
#define is_granularity_aligned(S)\
   (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)

/*  True if segment S holds address A */
#define segment_holds(S, A)\
  ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)

/* Return segment holding given address */
static msegmentptr segment_holding(mstate m, char* addr) {
  msegmentptr sp = &m->seg;
  for (;;) {
    if (addr >= sp->base && addr < sp->base + sp->size)
      return sp;
    if ((sp = sp->next) == 0)
      return 0;
  }
}

/* Return true if segment contains a segment link */
static int has_segment_link(mstate m, msegmentptr ss) {
  msegmentptr sp = &m->seg;
  for (;;) {
    if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
      return 1;
    if ((sp = sp->next) == 0)
      return 0;
  }
}

#ifndef MORECORE_CANNOT_TRIM
#define should_trim(M,s)  ((s) > (M)->trim_check)
#else  /* MORECORE_CANNOT_TRIM */
#define should_trim(M,s)  (0)
#endif /* MORECORE_CANNOT_TRIM */

/*
  TOP_FOOT_SIZE is padding at the end of a segment, including space
  that may be needed to place segment records and fenceposts when new
  noncontiguous segments are added.
*/
#define TOP_FOOT_SIZE\
  (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)


/* -------------------------------  Hooks -------------------------------- */

/*
  PREACTION should be defined to return 0 on success, and nonzero on
  failure. If you are not using locking, you can redefine these to do
  anything you like.
*/

#if USE_LOCKS
#define PREACTION(M)  ((use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
#define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
#else /* USE_LOCKS */

#ifndef PREACTION
#define PREACTION(M) (0)
#endif  /* PREACTION */

#ifndef POSTACTION
#define POSTACTION(M)
#endif  /* POSTACTION */

#endif /* USE_LOCKS */

/*
  CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
  USAGE_ERROR_ACTION is triggered on detected bad frees and
  reallocs. The argument p is an address that might have triggered the
  fault. It is ignored by the two predefined actions, but might be
  useful in custom actions that try to help diagnose errors.
*/

#if PROCEED_ON_ERROR

/* A count of the number of corruption errors causing resets */
int malloc_corruption_error_count;

/* default corruption action */
static void reset_on_error(mstate m);

#define CORRUPTION_ERROR_ACTION(m)  reset_on_error(m)
#define USAGE_ERROR_ACTION(m, p)

#else /* PROCEED_ON_ERROR */

#ifndef CORRUPTION_ERROR_ACTION
#define CORRUPTION_ERROR_ACTION(m) ABORT
#endif /* CORRUPTION_ERROR_ACTION */

#ifndef USAGE_ERROR_ACTION
#define USAGE_ERROR_ACTION(m,p) ABORT
#endif /* USAGE_ERROR_ACTION */

#endif /* PROCEED_ON_ERROR */


/* -------------------------- Debugging setup ---------------------------- */

#if ! DEBUG

#define check_free_chunk(M,P)
#define check_inuse_chunk(M,P)
#define check_malloced_chunk(M,P,N)
#define check_mmapped_chunk(M,P)
#define check_malloc_state(M)
#define check_top_chunk(M,P)

#else /* DEBUG */
#define check_free_chunk(M,P)       do_check_free_chunk(M,P)
#define check_inuse_chunk(M,P)      do_check_inuse_chunk(M,P)
#define check_top_chunk(M,P)        do_check_top_chunk(M,P)
#define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
#define check_mmapped_chunk(M,P)    do_check_mmapped_chunk(M,P)
#define check_malloc_state(M)       do_check_malloc_state(M)

static void   do_check_any_chunk(mstate m, mchunkptr p);
static void   do_check_top_chunk(mstate m, mchunkptr p);
static void   do_check_mmapped_chunk(mstate m, mchunkptr p);
static void   do_check_inuse_chunk(mstate m, mchunkptr p);
static void   do_check_free_chunk(mstate m, mchunkptr p);
static void   do_check_malloced_chunk(mstate m, void* mem, size_t s);
static void   do_check_tree(mstate m, tchunkptr t);
static void   do_check_treebin(mstate m, bindex_t i);
static void   do_check_smallbin(mstate m, bindex_t i);
static void   do_check_malloc_state(mstate m);
static int    bin_find(mstate m, mchunkptr x);
static size_t traverse_and_check(mstate m);
#endif /* DEBUG */

/* ---------------------------- Indexing Bins ---------------------------- */

#define is_small(s)         (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
#define small_index(s)      (bindex_t)((s)  >> SMALLBIN_SHIFT)
#define small_index2size(i) ((i)  << SMALLBIN_SHIFT)
#define MIN_SMALL_INDEX     (small_index(MIN_CHUNK_SIZE))

/* addressing by index. See above about smallbin repositioning */
#define smallbin_at(M, i)   ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
#define treebin_at(M,i)     (&((M)->treebins[i]))

/* assign tree index for size S to variable I. Use x86 asm if possible  */
#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
#define compute_tree_index(S, I)\
{\
  unsigned int X = S >> TREEBIN_SHIFT;\
  if (X == 0)\
    I = 0;\
  else if (X > 0xFFFF)\
    I = NTREEBINS-1;\
  else {\
    unsigned int K = (unsigned) sizeof(X)*__CHAR_BIT__ - 1 - (unsigned) __builtin_clz(X); \
    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
  }\
}

#elif defined (__INTEL_COMPILER)
#define compute_tree_index(S, I)\
{\
  size_t X = S >> TREEBIN_SHIFT;\
  if (X == 0)\
    I = 0;\
  else if (X > 0xFFFF)\
    I = NTREEBINS-1;\
  else {\
    unsigned int K = _bit_scan_reverse (X); \
    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
  }\
}

#elif defined(_MSC_VER) && _MSC_VER>=1300
#define compute_tree_index(S, I)\
{\
  size_t X = S >> TREEBIN_SHIFT;\
  if (X == 0)\
    I = 0;\
  else if (X > 0xFFFF)\
    I = NTREEBINS-1;\
  else {\
    unsigned int K;\
    _BitScanReverse((DWORD *) &K, (DWORD) X);\
    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
  }\
}

#else /* GNUC */
#define compute_tree_index(S, I)\
{\
  size_t X = S >> TREEBIN_SHIFT;\
  if (X == 0)\
    I = 0;\
  else if (X > 0xFFFF)\
    I = NTREEBINS-1;\
  else {\
    unsigned int Y = (unsigned int)X;\
    unsigned int N = ((Y - 0x100) >> 16) & 8;\
    unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
    N += K;\
    N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
    K = 14 - N + ((Y <<= K) >> 15);\
    I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
  }\
}
#endif /* GNUC */

/* Bit representing maximum resolved size in a treebin at i */
#define bit_for_tree_index(i) \
   (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)

/* Shift placing maximum resolved bit in a treebin at i as sign bit */
#define leftshift_for_tree_index(i) \
   ((i == NTREEBINS-1)? 0 : \
    ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))

/* The size of the smallest chunk held in bin with index i */
#define minsize_for_tree_index(i) \
   ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) |  \
   (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))


/* ------------------------ Operations on bin maps ----------------------- */

/* bit corresponding to given index */
#define idx2bit(i)              ((binmap_t)(1) << (i))

/* Mark/Clear bits with given index */
#define mark_smallmap(M,i)      ((M)->smallmap |=  idx2bit(i))
#define clear_smallmap(M,i)     ((M)->smallmap &= ~idx2bit(i))
#define smallmap_is_marked(M,i) ((M)->smallmap &   idx2bit(i))

#define mark_treemap(M,i)       ((M)->treemap  |=  idx2bit(i))
#define clear_treemap(M,i)      ((M)->treemap  &= ~idx2bit(i))
#define treemap_is_marked(M,i)  ((M)->treemap  &   idx2bit(i))

/* isolate the least set bit of a bitmap */
#define least_bit(x)         ((x) & -(x))

/* mask with all bits to left of least bit of x on */
#define left_bits(x)         ((x<<1) | -(x<<1))

/* mask with all bits to left of or equal to least bit of x on */
#define same_or_left_bits(x) ((x) | -(x))

/* index corresponding to given bit. Use x86 asm if possible */

#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
#define compute_bit2idx(X, I)\
{\
  unsigned int J;\
  J = __builtin_ctz(X); \
  I = (bindex_t)J;\
}

#elif defined (__INTEL_COMPILER)
#define compute_bit2idx(X, I)\
{\
  unsigned int J;\
  J = _bit_scan_forward (X); \
  I = (bindex_t)J;\
}

#elif defined(_MSC_VER) && _MSC_VER>=1300
#define compute_bit2idx(X, I)\
{\
  unsigned int J;\
  _BitScanForward((DWORD *) &J, X);\
  I = (bindex_t)J;\
}

#elif USE_BUILTIN_FFS
#define compute_bit2idx(X, I) I = ffs(X)-1

#else
#define compute_bit2idx(X, I)\
{\
  unsigned int Y = X - 1;\
  unsigned int K = Y >> (16-4) & 16;\
  unsigned int N = K;        Y >>= K;\
  N += K = Y >> (8-3) &  8;  Y >>= K;\
  N += K = Y >> (4-2) &  4;  Y >>= K;\
  N += K = Y >> (2-1) &  2;  Y >>= K;\
  N += K = Y >> (1-0) &  1;  Y >>= K;\
  I = (bindex_t)(N + Y);\
}
#endif /* GNUC */


/* ----------------------- Runtime Check Support ------------------------- */

/*
  For security, the main invariant is that malloc/free/etc never
  writes to a static address other than malloc_state, unless static
  malloc_state itself has been corrupted, which cannot occur via
  malloc (because of these checks). In essence this means that we
  believe all pointers, sizes, maps etc held in malloc_state, but
  check all of those linked or offsetted from other embedded data
  structures.  These checks are interspersed with main code in a way
  that tends to minimize their run-time cost.

  When FOOTERS is defined, in addition to range checking, we also
  verify footer fields of inuse chunks, which can be used guarantee
  that the mstate controlling malloc/free is intact.  This is a
  streamlined version of the approach described by William Robertson
  et al in "Run-time Detection of Heap-based Overflows" LISA'03
  http://www.usenix.org/events/lisa03/tech/robertson.html The footer
  of an inuse chunk holds the xor of its mstate and a random seed,
  that is checked upon calls to free() and realloc().  This is
  (probabalistically) unguessable from outside the program, but can be
  computed by any code successfully malloc'ing any chunk, so does not
  itself provide protection against code that has already broken
  security through some other means.  Unlike Robertson et al, we
  always dynamically check addresses of all offset chunks (previous,
  next, etc). This turns out to be cheaper than relying on hashes.
*/

#if !INSECURE
/* Check if address a is at least as high as any from MORECORE or MMAP */
#define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
/* Check if address of next chunk n is higher than base chunk p */
#define ok_next(p, n)    ((char*)(p) < (char*)(n))
/* Check if p has inuse status */
#define ok_inuse(p)     is_inuse(p)
/* Check if p has its pinuse bit on */
#define ok_pinuse(p)     pinuse(p)

#else /* !INSECURE */
#define ok_address(M, a) (1)
#define ok_next(b, n)    (1)
#define ok_inuse(p)      (1)
#define ok_pinuse(p)     (1)
#endif /* !INSECURE */

#if (FOOTERS && !INSECURE)
/* Check if (alleged) mstate m has expected magic field */
#define ok_magic(M)      ((M)->magic == mparams.magic)
#else  /* (FOOTERS && !INSECURE) */
#define ok_magic(M)      (1)
#endif /* (FOOTERS && !INSECURE) */

/* In gcc, use __builtin_expect to minimize impact of checks */
#if !INSECURE
#if defined(__GNUC__) && __GNUC__ >= 3
#define RTCHECK(e)  __builtin_expect(e, 1)
#else /* GNUC */
#define RTCHECK(e)  (e)
#endif /* GNUC */
#else /* !INSECURE */
#define RTCHECK(e)  (1)
#endif /* !INSECURE */

/* macros to set up inuse chunks with or without footers */

#if !FOOTERS

#define mark_inuse_foot(M,p,s)

/* Macros for setting head/foot of non-mmapped chunks */

/* Set cinuse bit and pinuse bit of next chunk */
#define set_inuse(M,p,s)\
  ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
  ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)

/* Set cinuse and pinuse of this chunk and pinuse of next chunk */
#define set_inuse_and_pinuse(M,p,s)\
  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
  ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)

/* Set size, cinuse and pinuse bit of this chunk */
#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))

#else /* FOOTERS */

/* Set foot of inuse chunk to be xor of mstate and seed */
#define mark_inuse_foot(M,p,s)\
  (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))

#define get_mstate_for(p)\
  ((mstate)(((mchunkptr)((char*)(p) +\
    (chunksize(p))))->prev_foot ^ mparams.magic))

#define set_inuse(M,p,s)\
  ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
  (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
  mark_inuse_foot(M,p,s))

#define set_inuse_and_pinuse(M,p,s)\
  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
  (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
 mark_inuse_foot(M,p,s))

#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
  mark_inuse_foot(M, p, s))

#endif /* !FOOTERS */

/* ---------------------------- setting mparams -------------------------- */

#if LOCK_AT_FORK
static void pre_fork(void)         { ACQUIRE_LOCK(&(gm)->mutex); }
static void post_fork_parent(void) { RELEASE_LOCK(&(gm)->mutex); }
static void post_fork_child(void)  { INITIAL_LOCK(&(gm)->mutex); }
#endif /* LOCK_AT_FORK */

/* Initialize mparams */
static int init_mparams(void) {
#ifdef NEED_GLOBAL_LOCK_INIT
  if (malloc_global_mutex_status <= 0)
    init_malloc_global_mutex();
#endif

  ACQUIRE_MALLOC_GLOBAL_LOCK();
  if (mparams.magic == 0) {
    size_t magic;
    size_t psize;
    size_t gsize;

#ifndef WIN32
    psize = malloc_getpagesize;
    gsize = ((DEFAULT_GRANULARITY != 0)? DEFAULT_GRANULARITY : psize);
#else /* WIN32 */
    {
      SYSTEM_INFO system_info;
      GetSystemInfo(&system_info);
      psize = system_info.dwPageSize;
      gsize = ((DEFAULT_GRANULARITY != 0)?
               DEFAULT_GRANULARITY : system_info.dwAllocationGranularity);
    }
#endif /* WIN32 */

    /* Sanity-check configuration:
       size_t must be unsigned and as wide as pointer type.
       ints must be at least 4 bytes.
       alignment must be at least 8.
       Alignment, min chunk size, and page size must all be powers of 2.
    */
    if ((sizeof(size_t) != sizeof(char*)) ||
        (MAX_SIZE_T < MIN_CHUNK_SIZE)  ||
        (sizeof(int) < 4)  ||
        (MALLOC_ALIGNMENT < (size_t)8U) ||
        ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) ||
        ((MCHUNK_SIZE      & (MCHUNK_SIZE-SIZE_T_ONE))      != 0) ||
        ((gsize            & (gsize-SIZE_T_ONE))            != 0) ||
        ((psize            & (psize-SIZE_T_ONE))            != 0))
      ABORT;
    mparams.granularity = gsize;
    mparams.page_size = psize;
    mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
    mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
#if MORECORE_CONTIGUOUS
    mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
#else  /* MORECORE_CONTIGUOUS */
    mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
#endif /* MORECORE_CONTIGUOUS */

#if !ONLY_MSPACES
    /* Set up lock for main malloc area */
    gm->mflags = mparams.default_mflags;
    (void)INITIAL_LOCK(&gm->mutex);
#endif
#if LOCK_AT_FORK
    pthread_atfork(&pre_fork, &post_fork_parent, &post_fork_child);
#endif

    {
#if USE_DEV_RANDOM
      int fd;
      unsigned char buf[sizeof(size_t)];
      /* Try to use /dev/urandom, else fall back on using time */
      if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
          read(fd, buf, sizeof(buf)) == sizeof(buf)) {
        magic = *((size_t *) buf);
        close(fd);
      }
      else
#endif /* USE_DEV_RANDOM */
      magic = (size_t)(rand64() ^ (size_t)0x55555555U);
      magic |= (size_t)8U;    /* ensure nonzero */
      magic &= ~(size_t)7U;   /* improve chances of fault for bad values */
      /* Until memory modes commonly available, use volatile-write */
      (*(volatile size_t *)(&(mparams.magic))) = magic;
    }
  }

  RELEASE_MALLOC_GLOBAL_LOCK();
  return 1;
}

/* support for mallopt */
static int change_mparam(int param_number, int value) {
  size_t val;
  ensure_initialization();
  val = (value == -1)? MAX_SIZE_T : (size_t)value;
  switch(param_number) {
  case M_TRIM_THRESHOLD:
    mparams.trim_threshold = val;
    return 1;
  case M_GRANULARITY:
    if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
      mparams.granularity = val;
      return 1;
    }
    else
      return 0;
  case M_MMAP_THRESHOLD:
    mparams.mmap_threshold = val;
    return 1;
  default:
    return 0;
  }
}

#if DEBUG
/* ------------------------- Debugging Support --------------------------- */

/* Check properties of any chunk, whether free, inuse, mmapped etc  */
static void do_check_any_chunk(mstate m, mchunkptr p) {
  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
  assert(ok_address(m, p));
}

/* Check properties of top chunk */
static void do_check_top_chunk(mstate m, mchunkptr p) {
  msegmentptr sp = segment_holding(m, (char*)p);
  size_t  sz = p->head & ~INUSE_BITS; /* third-lowest bit can be set! */
  assert(sp != 0);
  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
  assert(ok_address(m, p));
  assert(sz == m->topsize);
  assert(sz > 0);
  assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE);
  assert(pinuse(p));
  assert(!pinuse(chunk_plus_offset(p, sz)));
}

/* Check properties of (inuse) mmapped chunks */
static void do_check_mmapped_chunk(mstate m, mchunkptr p) {
  size_t  sz = chunksize(p);
  size_t len = (sz + (p->prev_foot) + MMAP_FOOT_PAD);
  assert(is_mmapped(p));
  assert(use_mmap(m));
  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
  assert(ok_address(m, p));
  assert(!is_small(sz));
  assert((len & (mparams.page_size-SIZE_T_ONE)) == 0);
  assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
  assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0);
}

/* Check properties of inuse chunks */
static void do_check_inuse_chunk(mstate m, mchunkptr p) {
  do_check_any_chunk(m, p);
  assert(is_inuse(p));
  assert(next_pinuse(p));
  /* If not pinuse and not mmapped, previous chunk has OK offset */
  assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
  if (is_mmapped(p))
    do_check_mmapped_chunk(m, p);
}

/* Check properties of free chunks */
static void do_check_free_chunk(mstate m, mchunkptr p) {
  size_t sz = chunksize(p);
  mchunkptr next = chunk_plus_offset(p, sz);
  do_check_any_chunk(m, p);
  assert(!is_inuse(p));
  assert(!next_pinuse(p));
  assert (!is_mmapped(p));
  if (p != m->dv && p != m->top) {
    if (sz >= MIN_CHUNK_SIZE) {
      assert((sz & CHUNK_ALIGN_MASK) == 0);
      assert(is_aligned(chunk2mem(p)));
      assert(next->prev_foot == sz);
      assert(pinuse(p));
      assert (next == m->top || is_inuse(next));
      assert(p->fd->bk == p);
      assert(p->bk->fd == p);
    }
    else  /* markers are always of size SIZE_T_SIZE */
      assert(sz == SIZE_T_SIZE);
  }
}

/* Check properties of malloced chunks at the point they are malloced */
static void do_check_malloced_chunk(mstate m, void* mem, size_t s) {
  if (mem != 0) {
    mchunkptr p = mem2chunk(mem);
    size_t sz = p->head & ~INUSE_BITS;
    do_check_inuse_chunk(m, p);
    assert((sz & CHUNK_ALIGN_MASK) == 0);
    assert(sz >= MIN_CHUNK_SIZE);
    assert(sz >= s);
    /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
    assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
  }
}

/* Check a tree and its subtrees.  */
static void do_check_tree(mstate m, tchunkptr t) {
  tchunkptr head = 0;
  tchunkptr u = t;
  bindex_t tindex = t->index;
  size_t tsize = chunksize(t);
  bindex_t idx;
  compute_tree_index(tsize, idx);
  assert(tindex == idx);
  assert(tsize >= MIN_LARGE_SIZE);
  assert(tsize >= minsize_for_tree_index(idx));
  assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1))));

  do { /* traverse through chain of same-sized nodes */
    do_check_any_chunk(m, ((mchunkptr)u));
    assert(u->index == tindex);
    assert(chunksize(u) == tsize);
    assert(!is_inuse(u));
    assert(!next_pinuse(u));
    assert(u->fd->bk == u);
    assert(u->bk->fd == u);
    if (u->parent == 0) {
      assert(u->child[0] == 0);
      assert(u->child[1] == 0);
    }
    else {
      assert(head == 0); /* only one node on chain has parent */
      head = u;
      assert(u->parent != u);
      assert (u->parent->child[0] == u ||
              u->parent->child[1] == u ||
              *((tbinptr*)(u->parent)) == u);
      if (u->child[0] != 0) {
        assert(u->child[0]->parent == u);
        assert(u->child[0] != u);
        do_check_tree(m, u->child[0]);
      }
      if (u->child[1] != 0) {
        assert(u->child[1]->parent == u);
        assert(u->child[1] != u);
        do_check_tree(m, u->child[1]);
      }
      if (u->child[0] != 0 && u->child[1] != 0) {
        assert(chunksize(u->child[0]) < chunksize(u->child[1]));
      }
    }
    u = u->fd;
  } while (u != t);
  assert(head != 0);
}

/*  Check all the chunks in a treebin.  */
static void do_check_treebin(mstate m, bindex_t i) {
  tbinptr* tb = treebin_at(m, i);
  tchunkptr t = *tb;
  int empty = (m->treemap & (1U << i)) == 0;
  if (t == 0)
    assert(empty);
  if (!empty)
    do_check_tree(m, t);
}

/*  Check all the chunks in a smallbin.  */
static void do_check_smallbin(mstate m, bindex_t i) {
  sbinptr b = smallbin_at(m, i);
  mchunkptr p = b->bk;
  unsigned int empty = (m->smallmap & (1U << i)) == 0;
  if (p == b)
    assert(empty);
  if (!empty) {
    for (; p != b; p = p->bk) {
      size_t size = chunksize(p);
      mchunkptr q;
      /* each chunk claims to be free */
      do_check_free_chunk(m, p);
      /* chunk belongs in bin */
      assert(small_index(size) == i);
      assert(p->bk == b || chunksize(p->bk) == chunksize(p));
      /* chunk is followed by an inuse chunk */
      q = next_chunk(p);
      if (q->head != FENCEPOST_HEAD)
        do_check_inuse_chunk(m, q);
    }
  }
}

/* Find x in a bin. Used in other check functions. */
static int bin_find(mstate m, mchunkptr x) {
  size_t size = chunksize(x);
  if (is_small(size)) {
    bindex_t sidx = small_index(size);
    sbinptr b = smallbin_at(m, sidx);
    if (smallmap_is_marked(m, sidx)) {
      mchunkptr p = b;
      do {
        if (p == x)
          return 1;
      } while ((p = p->fd) != b);
    }
  }
  else {
    bindex_t tidx;
    compute_tree_index(size, tidx);
    if (treemap_is_marked(m, tidx)) {
      tchunkptr t = *treebin_at(m, tidx);
      size_t sizebits = size << leftshift_for_tree_index(tidx);
      while (t != 0 && chunksize(t) != size) {
        t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
        sizebits <<= 1;
      }
      if (t != 0) {
        tchunkptr u = t;
        do {
          if (u == (tchunkptr)x)
            return 1;
        } while ((u = u->fd) != t);
      }
    }
  }
  return 0;
}

/* Traverse each chunk and check it; return total */
static size_t traverse_and_check(mstate m) {
  size_t sum = 0;
  if (is_initialized(m)) {
    msegmentptr s = &m->seg;
    sum += m->topsize + TOP_FOOT_SIZE;
    while (s != 0) {
      mchunkptr q = align_as_chunk(s->base);
      mchunkptr lastq = 0;
      assert(pinuse(q));
      while (segment_holds(s, q) &&
             q != m->top && q->head != FENCEPOST_HEAD) {
        sum += chunksize(q);
        if (is_inuse(q)) {
          assert(!bin_find(m, q));
          do_check_inuse_chunk(m, q);
        }
        else {
          assert(q == m->dv || bin_find(m, q));
          assert(lastq == 0 || is_inuse(lastq)); /* Not 2 consecutive free */
          do_check_free_chunk(m, q);
        }
        lastq = q;
        q = next_chunk(q);
      }
      s = s->next;
    }
  }
  return sum;
}


/* Check all properties of malloc_state. */
static void do_check_malloc_state(mstate m) {
  bindex_t i;
  size_t total;
  /* check bins */
  for (i = 0; i < NSMALLBINS; ++i)
    do_check_smallbin(m, i);
  for (i = 0; i < NTREEBINS; ++i)
    do_check_treebin(m, i);

  if (m->dvsize != 0) { /* check dv chunk */
    do_check_any_chunk(m, m->dv);
    assert(m->dvsize == chunksize(m->dv));
    assert(m->dvsize >= MIN_CHUNK_SIZE);
    assert(bin_find(m, m->dv) == 0);
  }

  if (m->top != 0) {   /* check top chunk */
    do_check_top_chunk(m, m->top);
    /*assert(m->topsize == chunksize(m->top)); redundant */
    assert(m->topsize > 0);
    assert(bin_find(m, m->top) == 0);
  }

  total = traverse_and_check(m);
  assert(total <= m->footprint);
  assert(m->footprint <= m->max_footprint);
}
#endif /* DEBUG */

/* ----------------------------- statistics ------------------------------ */

#if !NO_MALLINFO
static struct mallinfo internal_mallinfo(mstate m) {
  struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
  ensure_initialization();
  if (!PREACTION(m)) {
    check_malloc_state(m);
    if (is_initialized(m)) {
      size_t nfree = SIZE_T_ONE; /* top always free */
      size_t mfree = m->topsize + TOP_FOOT_SIZE;
      size_t sum = mfree;
      msegmentptr s = &m->seg;
      while (s != 0) {
        mchunkptr q = align_as_chunk(s->base);
        while (segment_holds(s, q) &&
               q != m->top && q->head != FENCEPOST_HEAD) {
          size_t sz = chunksize(q);
          sum += sz;
          if (!is_inuse(q)) {
            mfree += sz;
            ++nfree;
          }
          q = next_chunk(q);
        }
        s = s->next;
      }

      nm.arena    = sum;
      nm.ordblks  = nfree;
      nm.hblkhd   = m->footprint - sum;
      nm.usmblks  = m->max_footprint;
      nm.uordblks = m->footprint - mfree;
      nm.fordblks = mfree;
      nm.keepcost = m->topsize;
    }

    POSTACTION(m);
  }
  return nm;
}
#endif /* !NO_MALLINFO */

#if !NO_MALLOC_STATS
static void internal_malloc_stats(mstate m) {
  ensure_initialization();
  if (!PREACTION(m)) {
    size_t maxfp = 0;
    size_t fp = 0;
    size_t used = 0;
    check_malloc_state(m);
    if (is_initialized(m)) {
      msegmentptr s = &m->seg;
      maxfp = m->max_footprint;
      fp = m->footprint;
      used = fp - (m->topsize + TOP_FOOT_SIZE);

      while (s != 0) {
        mchunkptr q = align_as_chunk(s->base);
        while (segment_holds(s, q) &&
               q != m->top && q->head != FENCEPOST_HEAD) {
          if (!is_inuse(q))
            used -= chunksize(q);
          q = next_chunk(q);
        }
        s = s->next;
      }
    }
    POSTACTION(m); /* drop lock */
    kprintf("max system bytes = %10lu\n", (unsigned long)(maxfp));
    kprintf("system bytes     = %10lu\n", (unsigned long)(fp));
    kprintf("in use bytes     = %10lu\n", (unsigned long)(used));
  }
}
#endif /* NO_MALLOC_STATS */

/* ----------------------- Operations on smallbins ----------------------- */

/*
  Various forms of linking and unlinking are defined as macros.  Even
  the ones for trees, which are very long but have very short typical
  paths.  This is ugly but reduces reliance on inlining support of
  compilers.
*/

/* Link a free chunk into a smallbin  */
#define insert_small_chunk(M, P, S) {\
  bindex_t I  = small_index(S);\
  mchunkptr B = smallbin_at(M, I);\
  mchunkptr F = B;\
  assert(S >= MIN_CHUNK_SIZE);\
  if (!smallmap_is_marked(M, I))\
    mark_smallmap(M, I);\
  else if (RTCHECK(ok_address(M, B->fd)))\
    F = B->fd;\
  else {\
    CORRUPTION_ERROR_ACTION(M);\
  }\
  B->fd = P;\
  F->bk = P;\
  P->fd = F;\
  P->bk = B;\
}

/* Unlink a chunk from a smallbin  */
#define unlink_small_chunk(M, P, S) {\
  mchunkptr F = P->fd;\
  mchunkptr B = P->bk;\
  bindex_t I = small_index(S);\
  assert(P != B);\
  assert(P != F);\
  assert(chunksize(P) == small_index2size(I));\
  if (RTCHECK(F == smallbin_at(M,I) || (ok_address(M, F) && F->bk == P))) { \
    if (B == F) {\
      clear_smallmap(M, I);\
    }\
    else if (RTCHECK(B == smallbin_at(M,I) ||\
                     (ok_address(M, B) && B->fd == P))) {\
      F->bk = B;\
      B->fd = F;\
    }\
    else {\
      CORRUPTION_ERROR_ACTION(M);\
    }\
  }\
  else {\
    CORRUPTION_ERROR_ACTION(M);\
  }\
}

/* Unlink the first chunk from a smallbin */
#define unlink_first_small_chunk(M, B, P, I) {\
  mchunkptr F = P->fd;\
  assert(P != B);\
  assert(P != F);\
  assert(chunksize(P) == small_index2size(I));\
  if (B == F) {\
    clear_smallmap(M, I);\
  }\
  else if (RTCHECK(ok_address(M, F) && F->bk == P)) {\
    F->bk = B;\
    B->fd = F;\
  }\
  else {\
    CORRUPTION_ERROR_ACTION(M);\
  }\
}

/* Replace dv node, binning the old one */
/* Used only when dvsize known to be small */
#define replace_dv(M, P, S) {\
  size_t DVS = M->dvsize;\
  assert(is_small(DVS));\
  if (DVS != 0) {\
    mchunkptr DV = M->dv;\
    insert_small_chunk(M, DV, DVS);\
  }\
  M->dvsize = S;\
  M->dv = P;\
}

/* ------------------------- Operations on trees ------------------------- */

/* Insert chunk into tree */
#define insert_large_chunk(M, X, S) {\
  tbinptr* H;\
  bindex_t I;\
  compute_tree_index(S, I);\
  H = treebin_at(M, I);\
  X->index = I;\
  X->child[0] = X->child[1] = 0;\
  if (!treemap_is_marked(M, I)) {\
    mark_treemap(M, I);\
    *H = X;\
    X->parent = (tchunkptr)H;\
    X->fd = X->bk = X;\
  }\
  else {\
    tchunkptr T = *H;\
    size_t K = S << leftshift_for_tree_index(I);\
    for (;;) {\
      if (chunksize(T) != S) {\
        tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
        K <<= 1;\
        if (*C != 0)\
          T = *C;\
        else if (RTCHECK(ok_address(M, C))) {\
          *C = X;\
          X->parent = T;\
          X->fd = X->bk = X;\
          break;\
        }\
        else {\
          CORRUPTION_ERROR_ACTION(M);\
          break;\
        }\
      }\
      else {\
        tchunkptr F = T->fd;\
        if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
          T->fd = F->bk = X;\
          X->fd = F;\
          X->bk = T;\
          X->parent = 0;\
          break;\
        }\
        else {\
          CORRUPTION_ERROR_ACTION(M);\
          break;\
        }\
      }\
    }\
  }\
}

/*
  Unlink steps:

  1. If x is a chained node, unlink it from its same-sized fd/bk links
     and choose its bk node as its replacement.
  2. If x was the last node of its size, but not a leaf node, it must
     be replaced with a leaf node (not merely one with an open left or
     right), to make sure that lefts and rights of descendents
     correspond properly to bit masks.  We use the rightmost descendent
     of x.  We could use any other leaf, but this is easy to locate and
     tends to counteract removal of leftmosts elsewhere, and so keeps
     paths shorter than minimally guaranteed.  This doesn't loop much
     because on average a node in a tree is near the bottom.
  3. If x is the base of a chain (i.e., has parent links) relink
     x's parent and children to x's replacement (or null if none).
*/

#define unlink_large_chunk(M, X) {\
  tchunkptr XP = X->parent;\
  tchunkptr R;\
  if (X->bk != X) {\
    tchunkptr F = X->fd;\
    R = X->bk;\
    if (RTCHECK(ok_address(M, F) && F->bk == X && R->fd == X)) {\
      F->bk = R;\
      R->fd = F;\
    }\
    else {\
      CORRUPTION_ERROR_ACTION(M);\
    }\
  }\
  else {\
    tchunkptr* RP;\
    if (((R = *(RP = &(X->child[1]))) != 0) ||\
        ((R = *(RP = &(X->child[0]))) != 0)) {\
      tchunkptr* CP;\
      while ((*(CP = &(R->child[1])) != 0) ||\
             (*(CP = &(R->child[0])) != 0)) {\
        R = *(RP = CP);\
      }\
      if (RTCHECK(ok_address(M, RP)))\
        *RP = 0;\
      else {\
        CORRUPTION_ERROR_ACTION(M);\
      }\
    }\
  }\
  if (XP != 0) {\
    tbinptr* H = treebin_at(M, X->index);\
    if (X == *H) {\
      if ((*H = R) == 0) \
        clear_treemap(M, X->index);\
    }\
    else if (RTCHECK(ok_address(M, XP))) {\
      if (XP->child[0] == X) \
        XP->child[0] = R;\
      else \
        XP->child[1] = R;\
    }\
    else\
      CORRUPTION_ERROR_ACTION(M);\
    if (R != 0) {\
      if (RTCHECK(ok_address(M, R))) {\
        tchunkptr C0, C1;\
        R->parent = XP;\
        if ((C0 = X->child[0]) != 0) {\
          if (RTCHECK(ok_address(M, C0))) {\
            R->child[0] = C0;\
            C0->parent = R;\
          }\
          else\
            CORRUPTION_ERROR_ACTION(M);\
        }\
        if ((C1 = X->child[1]) != 0) {\
          if (RTCHECK(ok_address(M, C1))) {\
            R->child[1] = C1;\
            C1->parent = R;\
          }\
          else\
            CORRUPTION_ERROR_ACTION(M);\
        }\
      }\
      else\
        CORRUPTION_ERROR_ACTION(M);\
    }\
  }\
}

/* Relays to large vs small bin operations */

#define insert_chunk(M, P, S)\
  if (is_small(S)) insert_small_chunk(M, P, S)\
  else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }

#define unlink_chunk(M, P, S)\
  if (is_small(S)) unlink_small_chunk(M, P, S)\
  else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }


/* Relays to internal calls to malloc/free from realloc, memalign etc */

#if ONLY_MSPACES
#define internal_malloc(m, b) mspace_malloc(m, b)
#define internal_free(m, mem) mspace_free(m,mem);
#else /* ONLY_MSPACES */
#if MSPACES
#define internal_malloc(m, b)\
  ((m == gm)? dlmalloc(b) : mspace_malloc(m, b))
#define internal_free(m, mem)\
   if (m == gm) dlfree(mem); else mspace_free(m,mem);
#else /* MSPACES */
#define internal_malloc(m, b) dlmalloc(b)
#define internal_free(m, mem) dlfree(mem)
#endif /* MSPACES */
#endif /* ONLY_MSPACES */

/* -----------------------  Direct-mmapping chunks ----------------------- */

/*
  Directly mmapped chunks are set up with an offset to the start of
  the mmapped region stored in the prev_foot field of the chunk. This
  allows reconstruction of the required argument to MUNMAP when freed,
  and also allows adjustment of the returned chunk to meet alignment
  requirements (especially in memalign).
*/

/* Malloc using mmap */
static void* mmap_alloc(mstate m, size_t nb) {
  size_t mmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
  if (m->footprint_limit != 0) {
    size_t fp = m->footprint + mmsize;
    if (fp <= m->footprint || fp > m->footprint_limit)
      return 0;
  }
  if (mmsize > nb) {     /* Check for wrap around 0 */
    char* mm = (char*)(dlmalloc_requires_more_vespene_gas(mmsize));
    if (mm != CMFAIL) {
      size_t offset = align_offset(chunk2mem(mm));
      size_t psize = mmsize - offset - MMAP_FOOT_PAD;
      mchunkptr p = (mchunkptr)(mm + offset);
      p->prev_foot = offset;
      p->head = psize;
      mark_inuse_foot(m, p, psize);
      chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
      chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;

      if (m->least_addr == 0 || mm < m->least_addr)
        m->least_addr = mm;
      if ((m->footprint += mmsize) > m->max_footprint)
        m->max_footprint = m->footprint;
      assert(is_aligned(chunk2mem(p)));
      check_mmapped_chunk(m, p);
      return chunk2mem(p);
    }
  }
  return 0;
}

/* Realloc using mmap */
static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb, int flags) {
  size_t oldsize = chunksize(oldp);
  (void)flags; /* placate people compiling -Wunused */
  if (is_small(nb)) /* Can't shrink mmap regions below small size */
    return 0;
  /* Keep old chunk if big enough but not too big */
  if (oldsize >= nb + SIZE_T_SIZE &&
      (oldsize - nb) <= (mparams.granularity << 1))
    return oldp;
  else {
    size_t offset = oldp->prev_foot;
    size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
    size_t newmmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
    char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
                                  oldmmsize, newmmsize, flags);
    if (cp != CMFAIL) {
      mchunkptr newp = (mchunkptr)(cp + offset);
      size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
      newp->head = psize;
      mark_inuse_foot(m, newp, psize);
      chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
      chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;

      if (cp < m->least_addr)
        m->least_addr = cp;
      if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
        m->max_footprint = m->footprint;
      check_mmapped_chunk(m, newp);
      return newp;
    }
  }
  return 0;
}


/* -------------------------- mspace management -------------------------- */

/* Initialize top chunk and its size */
static void init_top(mstate m, mchunkptr p, size_t psize) {
  /* Ensure alignment */
  size_t offset = align_offset(chunk2mem(p));
  p = (mchunkptr)((char*)p + offset);
  psize -= offset;

  m->top = p;
  m->topsize = psize;
  p->head = psize | PINUSE_BIT;
  /* set size of fake trailing chunk holding overhead space only once */
  chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
  m->trim_check = mparams.trim_threshold; /* reset on each update */
}

/* Initialize bins for a new mstate that is otherwise zeroed out */
static void init_bins(mstate m) {
  /* Establish circular links for smallbins */
  bindex_t i;
  for (i = 0; i < NSMALLBINS; ++i) {
    sbinptr bin = smallbin_at(m,i);
    bin->fd = bin->bk = bin;
  }
}

#if PROCEED_ON_ERROR

/* default corruption action */
static void reset_on_error(mstate m) {
  int i;
  ++malloc_corruption_error_count;
  /* Reinitialize fields to forget about all memory */
  m->smallmap = m->treemap = 0;
  m->dvsize = m->topsize = 0;
  m->seg.base = 0;
  m->seg.size = 0;
  m->seg.next = 0;
  m->top = m->dv = 0;
  for (i = 0; i < NTREEBINS; ++i)
    *treebin_at(m, i) = 0;
  init_bins(m);
}
#endif /* PROCEED_ON_ERROR */

/* Allocate chunk and prepend remainder with chunk in successor base. */
static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
                           size_t nb) {
  mchunkptr p = align_as_chunk(newbase);
  mchunkptr oldfirst = align_as_chunk(oldbase);
  size_t psize = (char*)oldfirst - (char*)p;
  mchunkptr q = chunk_plus_offset(p, nb);
  size_t qsize = psize - nb;
  set_size_and_pinuse_of_inuse_chunk(m, p, nb);

  assert((char*)oldfirst > (char*)q);
  assert(pinuse(oldfirst));
  assert(qsize >= MIN_CHUNK_SIZE);

  /* consolidate remainder with first chunk of old base */
  if (oldfirst == m->top) {
    size_t tsize = m->topsize += qsize;
    m->top = q;
    q->head = tsize | PINUSE_BIT;
    check_top_chunk(m, q);
  }
  else if (oldfirst == m->dv) {
    size_t dsize = m->dvsize += qsize;
    m->dv = q;
    set_size_and_pinuse_of_free_chunk(q, dsize);
  }
  else {
    if (!is_inuse(oldfirst)) {
      size_t nsize = chunksize(oldfirst);
      unlink_chunk(m, oldfirst, nsize);
      oldfirst = chunk_plus_offset(oldfirst, nsize);
      qsize += nsize;
    }
    set_free_with_pinuse(q, qsize, oldfirst);
    insert_chunk(m, q, qsize);
    check_free_chunk(m, q);
  }

  check_malloced_chunk(m, chunk2mem(p), nb);
  return chunk2mem(p);
}

/* Add a segment to hold a new noncontiguous region */
static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
  /* Determine locations and sizes of segment, fenceposts, old top */
  char* old_top = (char*)m->top;
  msegmentptr oldsp = segment_holding(m, old_top);
  char* old_end = oldsp->base + oldsp->size;
  size_t ssize = pad_request(sizeof(struct malloc_segment));
  char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
  size_t offset = align_offset(chunk2mem(rawsp));
  char* asp = rawsp + offset;
  char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
  mchunkptr sp = (mchunkptr)csp;
  msegmentptr ss = (msegmentptr)(chunk2mem(sp));
  mchunkptr tnext = chunk_plus_offset(sp, ssize);
  mchunkptr p = tnext;
  int nfences = 0;

  /* reset top to new space */
  init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);

  /* Set up segment record */
  assert(is_aligned(ss));
  set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
  *ss = m->seg; /* Push current record */
  m->seg.base = tbase;
  m->seg.size = tsize;
  m->seg.sflags = mmapped;
  m->seg.next = ss;

  /* Insert trailing fenceposts */
  for (;;) {
    mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
    p->head = FENCEPOST_HEAD;
    ++nfences;
    if ((char*)(&(nextp->head)) < old_end)
      p = nextp;
    else
      break;
  }
  assert(nfences >= 2);

  /* Insert the rest of old top into a bin as an ordinary free chunk */
  if (csp != old_top) {
    mchunkptr q = (mchunkptr)old_top;
    size_t psize = csp - old_top;
    mchunkptr tn = chunk_plus_offset(q, psize);
    set_free_with_pinuse(q, psize, tn);
    insert_chunk(m, q, psize);
  }

  check_top_chunk(m, m->top);
}

/* -------------------------- System allocation -------------------------- */

/* Get memory from system using MORECORE or MMAP */
static void* sys_alloc(mstate m, size_t nb) {
  char* tbase = CMFAIL;
  size_t tsize = 0;
  flag_t mmap_flag = 0;
  size_t asize; /* allocation size */

  ensure_initialization();

  /* Directly map large chunks, but only if already initialized */
  if (use_mmap(m) && nb >= mparams.mmap_threshold && m->topsize != 0) {
    void* mem = mmap_alloc(m, nb);
    if (mem != 0)
      return mem;
  }

  asize = granularity_align(nb + SYS_ALLOC_PADDING);
  if (asize <= nb)
    return 0; /* wraparound */
  if (m->footprint_limit != 0) {
    size_t fp = m->footprint + asize;
    if (fp <= m->footprint || fp > m->footprint_limit)
      return 0;
  }

  /*
    Try getting memory in any of three ways (in most-preferred to
    least-preferred order):
    1. A call to MORECORE that can normally contiguously extend memory.
       (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
       or main space is mmapped or a previous contiguous call failed)
    2. A call to MMAP new space (disabled if not HAVE_MMAP).
       Note that under the default settings, if MORECORE is unable to
       fulfill a 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
       find space.
    3. A call to MORECORE that cannot usually contiguously extend memory.
       (disabled if not HAVE_MORECORE)

   In all cases, we need to request enough bytes from system to ensure
   we can malloc nb bytes upon success, so pad with enough space for
   top_foot, plus alignment-pad to make sure we don't lose bytes if
   not on boundary, and round this up to a granularity unit.
  */

  if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
    char* br = CMFAIL;
    size_t ssize = asize; /* sbrk call size */
    msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
    ACQUIRE_MALLOC_GLOBAL_LOCK();

    if (ss == 0) {  /* First time through or recovery */
      char* base = (char*)CALL_MORECORE(0);
      if (base != CMFAIL) {
        size_t fp;
        /* Adjust to end on a page boundary */
        if (!is_page_aligned(base))
          ssize += (page_align((size_t)base) - (size_t)base);
        fp = m->footprint + ssize; /* recheck limits */
        if (ssize > nb && ssize < HALF_MAX_SIZE_T &&
            (m->footprint_limit == 0 ||
             (fp > m->footprint && fp <= m->footprint_limit)) &&
            (br = (char*)(CALL_MORECORE(ssize))) == base) {
          tbase = base;
          tsize = ssize;
        }
      }
    }
    else {
      /* Subtract out existing available top space from MORECORE request. */
      ssize = granularity_align(nb - m->topsize + SYS_ALLOC_PADDING);
      /* Use mem here only if it did continuously extend old space */
      if (ssize < HALF_MAX_SIZE_T &&
          (br = (char*)(CALL_MORECORE(ssize))) == ss->base+ss->size) {
        tbase = br;
        tsize = ssize;
      }
    }

    if (tbase == CMFAIL) {    /* Cope with partial failure */
      if (br != CMFAIL) {    /* Try to use/extend the space we did get */
        if (ssize < HALF_MAX_SIZE_T &&
            ssize < nb + SYS_ALLOC_PADDING) {
          size_t esize = granularity_align(nb + SYS_ALLOC_PADDING - ssize);
          if (esize < HALF_MAX_SIZE_T) {
            char* end = (char*)CALL_MORECORE(esize);
            if (end != CMFAIL)
              ssize += esize;
            else {            /* Can't use; try to release */
              (void) CALL_MORECORE(-ssize);
              br = CMFAIL;
            }
          }
        }
      }
      if (br != CMFAIL) {    /* Use the space we did get */
        tbase = br;
        tsize = ssize;
      }
      else
        disable_contiguous(m); /* Don't try contiguous path in the future */
    }

    RELEASE_MALLOC_GLOBAL_LOCK();
  }

  if (HAVE_MMAP && tbase == CMFAIL) {  /* Try MMAP */
    char* mp = (char*)(dlmalloc_requires_more_vespene_gas(asize));
    if (mp != CMFAIL) {
      tbase = mp;
      tsize = asize;
      mmap_flag = USE_MMAP_BIT;
    }
  }

  if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
    if (asize < HALF_MAX_SIZE_T) {
      char* br = CMFAIL;
      char* end = CMFAIL;
      ACQUIRE_MALLOC_GLOBAL_LOCK();
      br = (char*)(CALL_MORECORE(asize));
      end = (char*)(CALL_MORECORE(0));
      RELEASE_MALLOC_GLOBAL_LOCK();
      if (br != CMFAIL && end != CMFAIL && br < end) {
        size_t ssize = end - br;
        if (ssize > nb + TOP_FOOT_SIZE) {
          tbase = br;
          tsize = ssize;
        }
      }
    }
  }

  if (tbase != CMFAIL) {

    if ((m->footprint += tsize) > m->max_footprint)
      m->max_footprint = m->footprint;

    if (!is_initialized(m)) { /* first-time initialization */
      if (m->least_addr == 0 || tbase < m->least_addr)
        m->least_addr = tbase;
      m->seg.base = tbase;
      m->seg.size = tsize;
      m->seg.sflags = mmap_flag;
      m->magic = mparams.magic;
      m->release_checks = MAX_RELEASE_CHECK_RATE;
      init_bins(m);
#if !ONLY_MSPACES
      if (is_global(m))
        init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
      else
#endif
      {
        /* Offset top by embedded malloc_state */
        mchunkptr mn = next_chunk(mem2chunk(m));
        init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
      }
    }

    else {
      /* Try to merge with an existing segment */
      msegmentptr sp = &m->seg;
      /* Only consider most recent segment if traversal suppressed */
      while (sp != 0 && tbase != sp->base + sp->size)
        sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
      if (sp != 0 &&
          !is_extern_segment(sp) &&
          (sp->sflags & USE_MMAP_BIT) == mmap_flag &&
          segment_holds(sp, m->top)) { /* append */
        sp->size += tsize;
        init_top(m, m->top, m->topsize + tsize);
      }
      else {
        if (tbase < m->least_addr)
          m->least_addr = tbase;
        sp = &m->seg;
        while (sp != 0 && sp->base != tbase + tsize)
          sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
        if (sp != 0 &&
            !is_extern_segment(sp) &&
            (sp->sflags & USE_MMAP_BIT) == mmap_flag) {
          char* oldbase = sp->base;
          sp->base = tbase;
          sp->size += tsize;
          return prepend_alloc(m, tbase, oldbase, nb);
        }
        else
          add_segment(m, tbase, tsize, mmap_flag);
      }
    }

    if (nb < m->topsize) { /* Allocate from new or extended top space */
      size_t rsize = m->topsize -= nb;
      mchunkptr p = m->top;
      mchunkptr r = m->top = chunk_plus_offset(p, nb);
      r->head = rsize | PINUSE_BIT;
      set_size_and_pinuse_of_inuse_chunk(m, p, nb);
      check_top_chunk(m, m->top);
      check_malloced_chunk(m, chunk2mem(p), nb);
      return chunk2mem(p);
    }
  }

  MALLOC_FAILURE_ACTION;
  return 0;
}

/* -----------------------  system deallocation -------------------------- */

/* Unmap and unlink any mmapped segments that don't contain used chunks */
static size_t release_unused_segments(mstate m) {
  size_t released = 0;
  int nsegs = 0;
  msegmentptr pred = &m->seg;
  msegmentptr sp = pred->next;
  while (sp != 0) {
    char* base = sp->base;
    size_t size = sp->size;
    msegmentptr next = sp->next;
    ++nsegs;
    if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
      mchunkptr p = align_as_chunk(base);
      size_t psize = chunksize(p);
      /* Can unmap if first chunk holds entire segment and not pinned */
      if (!is_inuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
        tchunkptr tp = (tchunkptr)p;
        assert(segment_holds(sp, (char*)sp));
        if (p == m->dv) {
          m->dv = 0;
          m->dvsize = 0;
        }
        else {
          unlink_large_chunk(m, tp);
        }
        if (CALL_MUNMAP(base, size) == 0) {
          released += size;
          m->footprint -= size;
          /* unlink obsoleted record */
          sp = pred;
          sp->next = next;
        }
        else { /* back out if cannot unmap */
          insert_large_chunk(m, tp, psize);
        }
      }
    }
    if (NO_SEGMENT_TRAVERSAL) /* scan only first segment */
      break;
    pred = sp;
    sp = next;
  }
  /* Reset check counter */
  m->release_checks = (((size_t) nsegs > (size_t) MAX_RELEASE_CHECK_RATE)?
                       (size_t) nsegs : (size_t) MAX_RELEASE_CHECK_RATE);
  return released;
}

static int sys_trim(mstate m, size_t pad) {
  size_t released = 0;
  ensure_initialization();
  if (pad < MAX_REQUEST && is_initialized(m)) {
    pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */

    if (m->topsize > pad) {
      /* Shrink top space in granularity-size units, keeping at least one */
      size_t unit = mparams.granularity;
      size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
                      SIZE_T_ONE) * unit;
      msegmentptr sp = segment_holding(m, (char*)m->top);

      if (!is_extern_segment(sp)) {
        if (is_mmapped_segment(sp)) {
          if (HAVE_MMAP &&
              sp->size >= extra &&
              !has_segment_link(m, sp)) { /* can't shrink if pinned */
            size_t newsize = sp->size - extra;
            (void)newsize; /* placate people compiling -Wunused-variable */
            /* Prefer mremap, fall back to munmap */
            if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
                (CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
              released = extra;
            }
          }
        }
        else if (HAVE_MORECORE) {
          if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
            extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
          ACQUIRE_MALLOC_GLOBAL_LOCK();
          {
            /* Make sure end of memory is where we last set it. */
            char* old_br = (char*)(CALL_MORECORE(0));
            if (old_br == sp->base + sp->size) {
              char* rel_br = (char*)(CALL_MORECORE(-extra));
              char* new_br = (char*)(CALL_MORECORE(0));
              if (rel_br != CMFAIL && new_br < old_br)
                released = old_br - new_br;
            }
          }
          RELEASE_MALLOC_GLOBAL_LOCK();
        }
      }

      if (released != 0) {
        sp->size -= released;
        m->footprint -= released;
        init_top(m, m->top, m->topsize - released);
        check_top_chunk(m, m->top);
      }
    }

    /* Unmap any unused mmapped segments */
    if (HAVE_MMAP)
      released += release_unused_segments(m);

    /* On failure, disable autotrim to avoid repeated failed future calls */
    if (released == 0 && m->topsize > m->trim_check)
      m->trim_check = MAX_SIZE_T;
  }

  return (released != 0)? 1 : 0;
}

/* Consolidate and bin a chunk. Differs from exported versions
   of free mainly in that the chunk need not be marked as inuse.
*/
static void dispose_chunk(mstate m, mchunkptr p, size_t psize) {
  mchunkptr next = chunk_plus_offset(p, psize);
  if (!pinuse(p)) {
    mchunkptr prev;
    size_t prevsize = p->prev_foot;
    if (is_mmapped(p)) {
      psize += prevsize + MMAP_FOOT_PAD;
      if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
        m->footprint -= psize;
      return;
    }
    prev = chunk_minus_offset(p, prevsize);
    psize += prevsize;
    p = prev;
    if (RTCHECK(ok_address(m, prev))) { /* consolidate backward */
      if (p != m->dv) {
        unlink_chunk(m, p, prevsize);
      }
      else if ((next->head & INUSE_BITS) == INUSE_BITS) {
        m->dvsize = psize;
        set_free_with_pinuse(p, psize, next);
        return;
      }
    }
    else {
      CORRUPTION_ERROR_ACTION(m);
      return;
    }
  }
  if (RTCHECK(ok_address(m, next))) {
    if (!cinuse(next)) {  /* consolidate forward */
      if (next == m->top) {
        size_t tsize = m->topsize += psize;
        m->top = p;
        p->head = tsize | PINUSE_BIT;
        if (p == m->dv) {
          m->dv = 0;
          m->dvsize = 0;
        }
        return;
      }
      else if (next == m->dv) {
        size_t dsize = m->dvsize += psize;
        m->dv = p;
        set_size_and_pinuse_of_free_chunk(p, dsize);
        return;
      }
      else {
        size_t nsize = chunksize(next);
        psize += nsize;
        unlink_chunk(m, next, nsize);
        set_size_and_pinuse_of_free_chunk(p, psize);
        if (p == m->dv) {
          m->dvsize = psize;
          return;
        }
      }
    }
    else {
      set_free_with_pinuse(p, psize, next);
    }
    insert_chunk(m, p, psize);
  }
  else {
    CORRUPTION_ERROR_ACTION(m);
  }
}

/* ---------------------------- malloc --------------------------- */

/* allocate a large request from the best fitting chunk in a treebin */
static void* tmalloc_large(mstate m, size_t nb) {
  tchunkptr v = 0;
  size_t rsize = -nb; /* Unsigned negation */
  tchunkptr t;
  bindex_t idx;
  compute_tree_index(nb, idx);
  if ((t = *treebin_at(m, idx)) != 0) {
    /* Traverse tree for this bin looking for node with size == nb */
    size_t sizebits = nb << leftshift_for_tree_index(idx);
    tchunkptr rst = 0;  /* The deepest untaken right subtree */
    for (;;) {
      tchunkptr rt;
      size_t trem = chunksize(t) - nb;
      if (trem < rsize) {
        v = t;
        if ((rsize = trem) == 0)
          break;
      }
      rt = t->child[1];
      t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
      if (rt != 0 && rt != t)
        rst = rt;
      if (t == 0) {
        t = rst; /* set t to least subtree holding sizes > nb */
        break;
      }
      sizebits <<= 1;
    }
  }
  if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
    binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
    if (leftbits != 0) {
      bindex_t i;
      binmap_t leastbit = least_bit(leftbits);
      compute_bit2idx(leastbit, i);
      t = *treebin_at(m, i);
    }
  }

  while (t != 0) { /* find smallest of tree or subtree */
    size_t trem = chunksize(t) - nb;
    if (trem < rsize) {
      rsize = trem;
      v = t;
    }
    t = leftmost_child(t);
  }

  /*  If dv is a better fit, return 0 so malloc will use it */
  if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
    if (RTCHECK(ok_address(m, v))) { /* split */
      mchunkptr r = chunk_plus_offset(v, nb);
      assert(chunksize(v) == rsize + nb);
      if (RTCHECK(ok_next(v, r))) {
        unlink_large_chunk(m, v);
        if (rsize < MIN_CHUNK_SIZE)
          set_inuse_and_pinuse(m, v, (rsize + nb));
        else {
          set_size_and_pinuse_of_inuse_chunk(m, v, nb);
          set_size_and_pinuse_of_free_chunk(r, rsize);
          insert_chunk(m, r, rsize);
        }
        return chunk2mem(v);
      }
    }
    CORRUPTION_ERROR_ACTION(m);
  }
  return 0;
}

/* allocate a small request from the best fitting chunk in a treebin */
static void* tmalloc_small(mstate m, size_t nb) {
  tchunkptr t, v;
  size_t rsize;
  bindex_t i;
  binmap_t leastbit = least_bit(m->treemap);
  compute_bit2idx(leastbit, i);
  v = t = *treebin_at(m, i);
  rsize = chunksize(t) - nb;

  while ((t = leftmost_child(t)) != 0) {
    size_t trem = chunksize(t) - nb;
    if (trem < rsize) {
      rsize = trem;
      v = t;
    }
  }

  if (RTCHECK(ok_address(m, v))) {
    mchunkptr r = chunk_plus_offset(v, nb);
    assert(chunksize(v) == rsize + nb);
    if (RTCHECK(ok_next(v, r))) {
      unlink_large_chunk(m, v);
      if (rsize < MIN_CHUNK_SIZE)
        set_inuse_and_pinuse(m, v, (rsize + nb));
      else {
        set_size_and_pinuse_of_inuse_chunk(m, v, nb);
        set_size_and_pinuse_of_free_chunk(r, rsize);
        replace_dv(m, r, rsize);
      }
      return chunk2mem(v);
    }
  }

  CORRUPTION_ERROR_ACTION(m);
  return 0;
}

#if !ONLY_MSPACES

void* dlmalloc(size_t bytes) {
  /*
     Basic algorithm:
     If a small request (< 256 bytes minus per-chunk overhead):
       1. If one exists, use a remainderless chunk in associated smallbin.
          (Remainderless means that there are too few excess bytes to
          represent as a chunk.)
       2. If it is big enough, use the dv chunk, which is normally the
          chunk adjacent to the one used for the most recent small request.
       3. If one exists, split the smallest available chunk in a bin,
          saving remainder in dv.
       4. If it is big enough, use the top chunk.
       5. If available, get memory from system and use it
     Otherwise, for a large request:
       1. Find the smallest available binned chunk that fits, and use it
          if it is better fitting than dv chunk, splitting if necessary.
       2. If better fitting than any binned chunk, use the dv chunk.
       3. If it is big enough, use the top chunk.
       4. If request size >= mmap threshold, try to directly mmap this chunk.
       5. If available, get memory from system and use it

     The ugly goto's here ensure that postaction occurs along all paths.
  */

#if USE_LOCKS
  ensure_initialization(); /* initialize in sys_alloc if not using locks */
#endif

  if (!PREACTION(gm)) {
    void* mem;
    size_t nb;
    if (bytes <= MAX_SMALL_REQUEST) {
      bindex_t idx;
      binmap_t smallbits;
      nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
      idx = small_index(nb);
      smallbits = gm->smallmap >> idx;

      if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
        mchunkptr b, p;
        idx += ~smallbits & 1;       /* Uses next bin if idx empty */
        b = smallbin_at(gm, idx);
        p = b->fd;
        assert(chunksize(p) == small_index2size(idx));
        unlink_first_small_chunk(gm, b, p, idx);
        set_inuse_and_pinuse(gm, p, small_index2size(idx));
        mem = chunk2mem(p);
        check_malloced_chunk(gm, mem, nb);
        goto postaction;
      }

      else if (nb > gm->dvsize) {
        if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
          mchunkptr b, p, r;
          size_t rsize;
          bindex_t i;
          binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
          binmap_t leastbit = least_bit(leftbits);
          compute_bit2idx(leastbit, i);
          b = smallbin_at(gm, i);
          p = b->fd;
          assert(chunksize(p) == small_index2size(i));
          unlink_first_small_chunk(gm, b, p, i);
          rsize = small_index2size(i) - nb;
          /* Fit here cannot be remainderless if 4byte sizes */
          if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
            set_inuse_and_pinuse(gm, p, small_index2size(i));
          else {
            set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
            r = chunk_plus_offset(p, nb);
            set_size_and_pinuse_of_free_chunk(r, rsize);
            replace_dv(gm, r, rsize);
          }
          mem = chunk2mem(p);
          check_malloced_chunk(gm, mem, nb);
          goto postaction;
        }

        else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
          check_malloced_chunk(gm, mem, nb);
          goto postaction;
        }
      }
    }
    else if (bytes >= MAX_REQUEST)
      nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
    else {
      nb = pad_request(bytes);
      if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
        check_malloced_chunk(gm, mem, nb);
        goto postaction;
      }
    }

    if (nb <= gm->dvsize) {
      size_t rsize = gm->dvsize - nb;
      mchunkptr p = gm->dv;
      if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
        mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
        gm->dvsize = rsize;
        set_size_and_pinuse_of_free_chunk(r, rsize);
        set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
      }
      else { /* exhaust dv */
        size_t dvs = gm->dvsize;
        gm->dvsize = 0;
        gm->dv = 0;
        set_inuse_and_pinuse(gm, p, dvs);
      }
      mem = chunk2mem(p);
      check_malloced_chunk(gm, mem, nb);
      goto postaction;
    }

    else if (nb < gm->topsize) { /* Split top */
      size_t rsize = gm->topsize -= nb;
      mchunkptr p = gm->top;
      mchunkptr r = gm->top = chunk_plus_offset(p, nb);
      r->head = rsize | PINUSE_BIT;
      set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
      mem = chunk2mem(p);
      check_top_chunk(gm, gm->top);
      check_malloced_chunk(gm, mem, nb);
      goto postaction;
    }

    mem = sys_alloc(gm, nb);
    POSTACTION(gm);
    if (mem == MAP_FAILED && weaken(__oom_hook)) {
      weaken(__oom_hook)(bytes);
    }
    return mem;

  postaction:
    POSTACTION(gm);
    return mem;
  }

  return 0;
}

/* ---------------------------- free --------------------------- */

void dlfree(void* mem) {
  /*
     Consolidate freed chunks with preceeding or succeeding bordering
     free chunks, if they exist, and then place in a bin.  Intermixed
     with special cases for top, dv, mmapped chunks, and usage errors.
  */

  if (mem != 0) {
    mchunkptr p  = mem2chunk(mem);
#if FOOTERS
    mstate fm = get_mstate_for(p);
    if (!ok_magic(fm)) {
      USAGE_ERROR_ACTION(fm, p);
      return;
    }
#else /* FOOTERS */
#define fm gm
#endif /* FOOTERS */
    if (!PREACTION(fm)) {
      check_inuse_chunk(fm, p);
      if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
        size_t psize = chunksize(p);
        mchunkptr next = chunk_plus_offset(p, psize);
        if (!pinuse(p)) {
          size_t prevsize = p->prev_foot;
          if (is_mmapped(p)) {
            psize += prevsize + MMAP_FOOT_PAD;
            if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
              fm->footprint -= psize;
            goto postaction;
          }
          else {
            mchunkptr prev = chunk_minus_offset(p, prevsize);
            psize += prevsize;
            p = prev;
            if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
              if (p != fm->dv) {
                unlink_chunk(fm, p, prevsize);
              }
              else if ((next->head & INUSE_BITS) == INUSE_BITS) {
                fm->dvsize = psize;
                set_free_with_pinuse(p, psize, next);
                goto postaction;
              }
            }
            else
              goto erroraction;
          }
        }

        if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
          if (!cinuse(next)) {  /* consolidate forward */
            if (next == fm->top) {
              size_t tsize = fm->topsize += psize;
              fm->top = p;
              p->head = tsize | PINUSE_BIT;
              if (p == fm->dv) {
                fm->dv = 0;
                fm->dvsize = 0;
              }
              if (should_trim(fm, tsize))
                sys_trim(fm, 0);
              goto postaction;
            }
            else if (next == fm->dv) {
              size_t dsize = fm->dvsize += psize;
              fm->dv = p;
              set_size_and_pinuse_of_free_chunk(p, dsize);
              goto postaction;
            }
            else {
              size_t nsize = chunksize(next);
              psize += nsize;
              unlink_chunk(fm, next, nsize);
              set_size_and_pinuse_of_free_chunk(p, psize);
              if (p == fm->dv) {
                fm->dvsize = psize;
                goto postaction;
              }
            }
          }
          else
            set_free_with_pinuse(p, psize, next);

          if (is_small(psize)) {
            insert_small_chunk(fm, p, psize);
            check_free_chunk(fm, p);
          }
          else {
            tchunkptr tp = (tchunkptr)p;
            insert_large_chunk(fm, tp, psize);
            check_free_chunk(fm, p);
            if (--fm->release_checks == 0)
              release_unused_segments(fm);
          }
          goto postaction;
        }
      }
    erroraction:
      USAGE_ERROR_ACTION(fm, p);
    postaction:
      POSTACTION(fm);
    }
  }
#if !FOOTERS
#undef fm
#endif /* FOOTERS */
}

void* dlcalloc(size_t n_elements, size_t elem_size) {
  void* mem;
  size_t req = 0;
  if (n_elements != 0) {
    req = n_elements * elem_size;
    if (((n_elements | elem_size) & ~(size_t)0xffff) &&
        (req / n_elements != elem_size))
      req = MAX_SIZE_T; /* force downstream failure on overflow */
  }
  mem = dlmalloc(req);
  if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
    bzero(mem, req);
  return mem;
}

#endif /* !ONLY_MSPACES */

/* ------------ Internal support for realloc, memalign, etc -------------- */

/* Try to realloc; only in-place unless can_move true */
static mchunkptr try_realloc_chunk(mstate m, mchunkptr p, size_t nb,
                                   int can_move) {
  mchunkptr newp = 0;
  size_t oldsize = chunksize(p);
  mchunkptr next = chunk_plus_offset(p, oldsize);
  if (RTCHECK(ok_address(m, p) && ok_inuse(p) &&
              ok_next(p, next) && ok_pinuse(next))) {
    if (is_mmapped(p)) {
      newp = mmap_resize(m, p, nb, can_move);
    }
    else if (oldsize >= nb) {             /* already big enough */
      size_t rsize = oldsize - nb;
      if (rsize >= MIN_CHUNK_SIZE) {      /* split off remainder */
        mchunkptr r = chunk_plus_offset(p, nb);
        set_inuse(m, p, nb);
        set_inuse(m, r, rsize);
        dispose_chunk(m, r, rsize);
      }
      newp = p;
    }
    else if (next == m->top) {  /* extend into top */
      if (oldsize + m->topsize > nb) {
        size_t newsize = oldsize + m->topsize;
        size_t newtopsize = newsize - nb;
        mchunkptr newtop = chunk_plus_offset(p, nb);
        set_inuse(m, p, nb);
        newtop->head = newtopsize |PINUSE_BIT;
        m->top = newtop;
        m->topsize = newtopsize;
        newp = p;
      }
    }
    else if (next == m->dv) { /* extend into dv */
      size_t dvs = m->dvsize;
      if (oldsize + dvs >= nb) {
        size_t dsize = oldsize + dvs - nb;
        if (dsize >= MIN_CHUNK_SIZE) {
          mchunkptr r = chunk_plus_offset(p, nb);
          mchunkptr n = chunk_plus_offset(r, dsize);
          set_inuse(m, p, nb);
          set_size_and_pinuse_of_free_chunk(r, dsize);
          clear_pinuse(n);
          m->dvsize = dsize;
          m->dv = r;
        }
        else { /* exhaust dv */
          size_t newsize = oldsize + dvs;
          set_inuse(m, p, newsize);
          m->dvsize = 0;
          m->dv = 0;
        }
        newp = p;
      }
    }
    else if (!cinuse(next)) { /* extend into next free chunk */
      size_t nextsize = chunksize(next);
      if (oldsize + nextsize >= nb) {
        size_t rsize = oldsize + nextsize - nb;
        unlink_chunk(m, next, nextsize);
        if (rsize < MIN_CHUNK_SIZE) {
          size_t newsize = oldsize + nextsize;
          set_inuse(m, p, newsize);
        }
        else {
          mchunkptr r = chunk_plus_offset(p, nb);
          set_inuse(m, p, nb);
          set_inuse(m, r, rsize);
          dispose_chunk(m, r, rsize);
        }
        newp = p;
      }
    }
  }
  else {
    USAGE_ERROR_ACTION(m, chunk2mem(p));
  }
  return newp;
}

static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
  void* mem = 0;
  if (alignment <  MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
    alignment = MIN_CHUNK_SIZE;
  if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
    size_t a = MALLOC_ALIGNMENT << 1;
    while (a < alignment) a <<= 1;
    alignment = a;
  }
  if (bytes >= MAX_REQUEST - alignment) {
    if (m != 0)  { /* Test isn't needed but avoids compiler warning */
      MALLOC_FAILURE_ACTION;
    }
  }
  else {
    size_t nb = request2size(bytes);
    size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
    mem = internal_malloc(m, req);
    if (mem != 0) {
      mchunkptr p = mem2chunk(mem);
      if (PREACTION(m))
        return 0;
      if ((((size_t)(mem)) & (alignment - 1)) != 0) { /* misaligned */
        /*
          Find an aligned spot inside chunk.  Since we need to give
          back leading space in a chunk of at least MIN_CHUNK_SIZE, if
          the first calculation places us at a spot with less than
          MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
          We've allocated enough total room so that this is always
          possible.
        */
        char* br = (char*)mem2chunk((size_t)(((size_t)((char*)mem + alignment -
                                                       SIZE_T_ONE)) &
                                             -alignment));
        char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
          br : br+alignment;
        mchunkptr newp = (mchunkptr)pos;
        size_t leadsize = pos - (char*)(p);
        size_t newsize = chunksize(p) - leadsize;

        if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
          newp->prev_foot = p->prev_foot + leadsize;
          newp->head = newsize;
        }
        else { /* Otherwise, give back leader, use the rest */
          set_inuse(m, newp, newsize);
          set_inuse(m, p, leadsize);
          dispose_chunk(m, p, leadsize);
        }
        p = newp;
      }

      /* Give back spare room at the end */
      if (!is_mmapped(p)) {
        size_t size = chunksize(p);
        if (size > nb + MIN_CHUNK_SIZE) {
          size_t remainder_size = size - nb;
          mchunkptr remainder = chunk_plus_offset(p, nb);
          set_inuse(m, p, nb);
          set_inuse(m, remainder, remainder_size);
          dispose_chunk(m, remainder, remainder_size);
        }
      }

      mem = chunk2mem(p);
      assert (chunksize(p) >= nb);
      assert(((size_t)mem & (alignment - 1)) == 0);
      check_inuse_chunk(m, p);
      POSTACTION(m);
    }
  }
  return mem;
}

/*
  Common support for independent_X routines, handling
    all of the combinations that can result.
  The opts arg has:
    bit 0 set if all elements are same size (using sizes[0])
    bit 1 set if elements should be zeroed
*/
static void** ialloc(mstate m,
                     size_t n_elements,
                     size_t* sizes,
                     int opts,
                     void* chunks[]) {

  size_t    element_size;   /* chunksize of each element, if all same */
  size_t    contents_size;  /* total size of elements */
  size_t    array_size;     /* request size of pointer array */
  void*     mem;            /* malloced aggregate space */
  mchunkptr p;              /* corresponding chunk */
  size_t    remainder_size; /* remaining bytes while splitting */
  void**    marray;         /* either "chunks" or malloced ptr array */
  mchunkptr array_chunk;    /* chunk for malloced ptr array */
  flag_t    was_enabled;    /* to disable mmap */
  size_t    size;
  size_t    i;

  ensure_initialization();
  /* compute array length, if needed */
  if (chunks != 0) {
    if (n_elements == 0)
      return chunks; /* nothing to do */
    marray = chunks;
    array_size = 0;
  }
  else {
    /* if empty req, must still return chunk representing empty array */
    if (n_elements == 0)
      return (void**)internal_malloc(m, 0);
    marray = 0;
    array_size = request2size(n_elements * (sizeof(void*)));
  }

  /* compute total element size */
  if (opts & 0x1) { /* all-same-size */
    element_size = request2size(*sizes);
    contents_size = n_elements * element_size;
  }
  else { /* add up all the sizes */
    element_size = 0;
    contents_size = 0;
    for (i = 0; i != n_elements; ++i)
      contents_size += request2size(sizes[i]);
  }

  size = contents_size + array_size;

  /*
     Allocate the aggregate chunk.  First disable direct-mmapping so
     malloc won't use it, since we would not be able to later
     free/realloc space internal to a segregated mmap region.
  */
  was_enabled = use_mmap(m);
  disable_mmap(m);
  mem = internal_malloc(m, size - CHUNK_OVERHEAD);
  if (was_enabled)
    enable_mmap(m);
  if (mem == 0)
    return 0;

  if (PREACTION(m)) return 0;
  p = mem2chunk(mem);
  remainder_size = chunksize(p);

  assert(!is_mmapped(p));

  if (opts & 0x2) {       /* optionally clear the elements */
    bzero((size_t*)mem, remainder_size - SIZE_T_SIZE - array_size);
  }

  /* If not provided, allocate the pointer array as final part of chunk */
  if (marray == 0) {
    size_t  array_chunk_size;
    array_chunk = chunk_plus_offset(p, contents_size);
    array_chunk_size = remainder_size - contents_size;
    marray = (void**) (chunk2mem(array_chunk));
    set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
    remainder_size = contents_size;
  }

  /* split out elements */
  for (i = 0; ; ++i) {
    marray[i] = chunk2mem(p);
    if (i != n_elements-1) {
      if (element_size != 0)
        size = element_size;
      else
        size = request2size(sizes[i]);
      remainder_size -= size;
      set_size_and_pinuse_of_inuse_chunk(m, p, size);
      p = chunk_plus_offset(p, size);
    }
    else { /* the final element absorbs any overallocation slop */
      set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
      break;
    }
  }

#if DEBUG
  if (marray != chunks) {
    /* final element must have exactly exhausted chunk */
    if (element_size != 0) {
      assert(remainder_size == element_size);
    }
    else {
      assert(remainder_size == request2size(sizes[i]));
    }
    check_inuse_chunk(m, mem2chunk(marray));
  }
  for (i = 0; i != n_elements; ++i)
    check_inuse_chunk(m, mem2chunk(marray[i]));

#endif /* DEBUG */

  POSTACTION(m);
  return marray;
}

/* Try to free all pointers in the given array.
   Note: this could be made faster, by delaying consolidation,
   at the price of disabling some user integrity checks, We
   still optimize some consolidations by combining adjacent
   chunks before freeing, which will occur often if allocated
   with ialloc or the array is sorted.
*/
static size_t internal_bulk_free(mstate m, void* array[], size_t nelem) {
  size_t unfreed = 0;
  if (!PREACTION(m)) {
    void** a;
    void** fence = &(array[nelem]);
    for (a = array; a != fence; ++a) {
      void* mem = *a;
      if (mem != 0) {
        mchunkptr p = mem2chunk(mem);
        size_t psize = chunksize(p);
#if FOOTERS
        if (get_mstate_for(p) != m) {
          ++unfreed;
          continue;
        }
#endif
        check_inuse_chunk(m, p);
        *a = 0;
        if (RTCHECK(ok_address(m, p) && ok_inuse(p))) {
          void ** b = a + 1; /* try to merge with next chunk */
          mchunkptr next = next_chunk(p);
          if (b != fence && *b == chunk2mem(next)) {
            size_t newsize = chunksize(next) + psize;
            set_inuse(m, p, newsize);
            *b = chunk2mem(p);
          }
          else
            dispose_chunk(m, p, psize);
        }
        else {
          CORRUPTION_ERROR_ACTION(m);
          break;
        }
      }
    }
    if (should_trim(m, m->topsize))
      sys_trim(m, 0);
    POSTACTION(m);
  }
  return unfreed;
}

/* Traversal */
#if MALLOC_INSPECT_ALL
static void internal_inspect_all(mstate m,
                                 void(*handler)(void *start,
                                                void *end,
                                                size_t used_bytes,
                                                void* callback_arg),
                                 void* arg) {
  if (is_initialized(m)) {
    mchunkptr top = m->top;
    msegmentptr s;
    for (s = &m->seg; s != 0; s = s->next) {
      mchunkptr q = align_as_chunk(s->base);
      while (segment_holds(s, q) && q->head != FENCEPOST_HEAD) {
        mchunkptr next = next_chunk(q);
        size_t sz = chunksize(q);
        size_t used;
        void* start;
        if (is_inuse(q)) {
          used = sz - CHUNK_OVERHEAD; /* must not be mmapped */
          start = chunk2mem(q);
        }
        else {
          used = 0;
          if (is_small(sz)) {     /* offset by possible bookkeeping */
            start = (void*)((char*)q + sizeof(struct malloc_chunk));
          }
          else {
            start = (void*)((char*)q + sizeof(struct malloc_tree_chunk));
          }
        }
        if (start < (void*)next)  /* skip if all space is bookkeeping */
          handler(start, next, used, arg);
        if (q == top)
          break;
        q = next;
      }
    }
  }
}
#endif /* MALLOC_INSPECT_ALL */

/* ------------------ Exported realloc, memalign, etc -------------------- */

#if !ONLY_MSPACES

void* dlrealloc(void* oldmem, size_t bytes) {
  void* mem = 0;
  if (oldmem == 0) {
    mem = dlmalloc(bytes);
  }
  else if (bytes >= MAX_REQUEST) {
    MALLOC_FAILURE_ACTION;
  }
#ifdef REALLOC_ZERO_BYTES_FREES
  else if (bytes == 0) {
    dlfree(oldmem);
  }
#endif /* REALLOC_ZERO_BYTES_FREES */
  else {
    size_t nb = request2size(bytes);
    mchunkptr oldp = mem2chunk(oldmem);
#if ! FOOTERS
    mstate m = gm;
#else /* FOOTERS */
    mstate m = get_mstate_for(oldp);
    if (!ok_magic(m)) {
      USAGE_ERROR_ACTION(m, oldmem);
      return 0;
    }
#endif /* FOOTERS */
    if (!PREACTION(m)) {
      mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
      POSTACTION(m);
      if (newp != 0) {
        check_inuse_chunk(m, newp);
        mem = chunk2mem(newp);
      }
      else {
        mem = internal_malloc(m, bytes);
        if (mem != 0) {
          size_t oc = chunksize(oldp) - overhead_for(oldp);
          memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
          internal_free(m, oldmem);
        }
      }
    }
  }
  return mem;
}

void* dlrealloc_in_place(void* oldmem, size_t bytes) {
  void* mem = 0;
  if (oldmem != 0) {
    if (bytes >= MAX_REQUEST) {
      MALLOC_FAILURE_ACTION;
    }
    else {
      size_t nb = request2size(bytes);
      mchunkptr oldp = mem2chunk(oldmem);
#if ! FOOTERS
      mstate m = gm;
#else /* FOOTERS */
      mstate m = get_mstate_for(oldp);
      if (!ok_magic(m)) {
        USAGE_ERROR_ACTION(m, oldmem);
        return 0;
      }
#endif /* FOOTERS */
      if (!PREACTION(m)) {
        mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
        POSTACTION(m);
        if (newp == oldp) {
          check_inuse_chunk(m, newp);
          mem = oldmem;
        }
      }
    }
  }
  return mem;
}

void* dlmemalign(size_t alignment, size_t bytes) {
  if (alignment <= MALLOC_ALIGNMENT) {
    return dlmalloc(bytes);
  }
  return internal_memalign(gm, alignment, bytes);
}

int dlposix_memalign(void** pp, size_t alignment, size_t bytes) {
  void* mem = 0;
  if (alignment == MALLOC_ALIGNMENT)
    mem = dlmalloc(bytes);
  else {
    size_t d = alignment / sizeof(void*);
    size_t r = alignment % sizeof(void*);
    if (r != 0 || d == 0 || (d & (d-SIZE_T_ONE)) != 0)
      return EINVAL;
    else if (bytes <= MAX_REQUEST - alignment) {
      if (alignment <  MIN_CHUNK_SIZE)
        alignment = MIN_CHUNK_SIZE;
      mem = internal_memalign(gm, alignment, bytes);
    }
  }
  if (!mem) {
    return ENOMEM;
  } else {
    *pp = mem;
    return 0;
  }
}

void* dlvalloc(size_t bytes) {
  size_t pagesz;
  ensure_initialization();
  pagesz = mparams.page_size;
  return dlmemalign(pagesz, bytes);
}

void* dlpvalloc(size_t bytes) {
  size_t pagesz;
  ensure_initialization();
  pagesz = mparams.page_size;
  return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
}

void** dlindependent_calloc(size_t n_elements, size_t elem_size,
                            void* chunks[]) {
  size_t sz = elem_size; /* serves as 1-element array */
  return ialloc(gm, n_elements, &sz, 3, chunks);
}

void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
                              void* chunks[]) {
  return ialloc(gm, n_elements, sizes, 0, chunks);
}

size_t dlbulk_free(void* array[], size_t nelem) {
  return internal_bulk_free(gm, array, nelem);
}

#if MALLOC_INSPECT_ALL
void dlmalloc_inspect_all(void(*handler)(void *start,
                                         void *end,
                                         size_t used_bytes,
                                         void* callback_arg),
                          void* arg) {
  ensure_initialization();
  if (!PREACTION(gm)) {
    internal_inspect_all(gm, handler, arg);
    POSTACTION(gm);
  }
}
#endif /* MALLOC_INSPECT_ALL */

int dlmalloc_trim(size_t pad) {
  int result = 0;
  ensure_initialization();
  if (!PREACTION(gm)) {
    result = sys_trim(gm, pad);
    POSTACTION(gm);
  }
  return result;
}

size_t dlmalloc_footprint(void) {
  return gm->footprint;
}

size_t dlmalloc_max_footprint(void) {
  return gm->max_footprint;
}

size_t dlmalloc_footprint_limit(void) {
  size_t maf = gm->footprint_limit;
  return maf == 0 ? MAX_SIZE_T : maf;
}

size_t dlmalloc_set_footprint_limit(size_t bytes) {
  size_t result;  /* invert sense of 0 */
  if (bytes == 0)
    result = granularity_align(1); /* Use minimal size */
  if (bytes == MAX_SIZE_T)
    result = 0;                    /* disable */
  else
    result = granularity_align(bytes);
  return gm->footprint_limit = result;
}

#if !NO_MALLINFO
struct mallinfo dlmallinfo(void) {
  return internal_mallinfo(gm);
}
#endif /* NO_MALLINFO */

#if !NO_MALLOC_STATS
void dlmalloc_stats() {
  internal_malloc_stats(gm);
}
#endif /* NO_MALLOC_STATS */

int dlmallopt(int param_number, int value) {
  return change_mparam(param_number, value);
}

size_t dlmalloc_usable_size(void* mem) {
  mchunkptr p;
  size_t bytes;
  if (mem) {
    p = mem2chunk(mem);
    if (is_inuse(p)) {
      bytes = chunksize(p) - overhead_for(p);
    } else {
      bytes = 0;
    }
  } else {
    bytes = 0;
  }
  return bytes;
}

#endif /* !ONLY_MSPACES */

/* ----------------------------- user mspaces ---------------------------- */

#if MSPACES

static mstate init_user_mstate(char* tbase, size_t tsize) {
  size_t msize = pad_request(sizeof(struct malloc_state));
  mchunkptr mn;
  mchunkptr msp = align_as_chunk(tbase);
  mstate m = (mstate)(chunk2mem(msp));
  bzero(m, msize);
  (void)INITIAL_LOCK(&m->mutex);
  msp->head = (msize|INUSE_BITS);
  m->seg.base = m->least_addr = tbase;
  m->seg.size = m->footprint = m->max_footprint = tsize;
  m->magic = mparams.magic;
  m->release_checks = MAX_RELEASE_CHECK_RATE;
  m->mflags = mparams.default_mflags;
  m->extp = 0;
  m->exts = 0;
  disable_contiguous(m);
  init_bins(m);
  mn = next_chunk(mem2chunk(m));
  init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) - TOP_FOOT_SIZE);
  check_top_chunk(m, m->top);
  return m;
}

mspace create_mspace(size_t capacity, int locked) {
  mstate m = 0;
  size_t msize;
  ensure_initialization();
  msize = pad_request(sizeof(struct malloc_state));
  if (capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
    size_t rs = ((capacity == 0)? mparams.granularity :
                 (capacity + TOP_FOOT_SIZE + msize));
    size_t tsize = granularity_align(rs);
    char* tbase = (char*)(dlmalloc_requires_more_vespene_gas(tsize));
    if (tbase != CMFAIL) {
      m = init_user_mstate(tbase, tsize);
      m->seg.sflags = USE_MMAP_BIT;
      set_lock(m, locked);
    }
  }
  return (mspace)m;
}

mspace create_mspace_with_base(void* base, size_t capacity, int locked) {
  mstate m = 0;
  size_t msize;
  ensure_initialization();
  msize = pad_request(sizeof(struct malloc_state));
  if (capacity > msize + TOP_FOOT_SIZE &&
      capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
    m = init_user_mstate((char*)base, capacity);
    m->seg.sflags = EXTERN_BIT;
    set_lock(m, locked);
  }
  return (mspace)m;
}

int mspace_track_large_chunks(mspace msp, int enable) {
  int ret = 0;
  mstate ms = (mstate)msp;
  if (!PREACTION(ms)) {
    if (!use_mmap(ms)) {
      ret = 1;
    }
    if (!enable) {
      enable_mmap(ms);
    } else {
      disable_mmap(ms);
    }
    POSTACTION(ms);
  }
  return ret;
}

size_t destroy_mspace(mspace msp) {
  size_t freed = 0;
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    msegmentptr sp = &ms->seg;
    (void)DESTROY_LOCK(&ms->mutex); /* destroy before unmapped */
    while (sp != 0) {
      char* base = sp->base;
      size_t size = sp->size;
      flag_t flag = sp->sflags;
      (void)base; /* placate people compiling -Wunused-variable */
      sp = sp->next;
      if ((flag & USE_MMAP_BIT) && !(flag & EXTERN_BIT) &&
          CALL_MUNMAP(base, size) == 0)
        freed += size;
    }
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return freed;
}

/*
  mspace versions of routines are near-clones of the global
  versions. This is not so nice but better than the alternatives.
*/

void* mspace_malloc(mspace msp, size_t bytes) {
  mstate ms = (mstate)msp;
  if (!ok_magic(ms)) {
    USAGE_ERROR_ACTION(ms,ms);
    return 0;
  }
  if (!PREACTION(ms)) {
    void* mem;
    size_t nb;
    if (bytes <= MAX_SMALL_REQUEST) {
      bindex_t idx;
      binmap_t smallbits;
      nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
      idx = small_index(nb);
      smallbits = ms->smallmap >> idx;

      if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
        mchunkptr b, p;
        idx += ~smallbits & 1;       /* Uses next bin if idx empty */
        b = smallbin_at(ms, idx);
        p = b->fd;
        assert(chunksize(p) == small_index2size(idx));
        unlink_first_small_chunk(ms, b, p, idx);
        set_inuse_and_pinuse(ms, p, small_index2size(idx));
        mem = chunk2mem(p);
        check_malloced_chunk(ms, mem, nb);
        goto postaction;
      }

      else if (nb > ms->dvsize) {
        if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
          mchunkptr b, p, r;
          size_t rsize;
          bindex_t i;
          binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
          binmap_t leastbit = least_bit(leftbits);
          compute_bit2idx(leastbit, i);
          b = smallbin_at(ms, i);
          p = b->fd;
          assert(chunksize(p) == small_index2size(i));
          unlink_first_small_chunk(ms, b, p, i);
          rsize = small_index2size(i) - nb;
          /* Fit here cannot be remainderless if 4byte sizes */
          if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
            set_inuse_and_pinuse(ms, p, small_index2size(i));
          else {
            set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
            r = chunk_plus_offset(p, nb);
            set_size_and_pinuse_of_free_chunk(r, rsize);
            replace_dv(ms, r, rsize);
          }
          mem = chunk2mem(p);
          check_malloced_chunk(ms, mem, nb);
          goto postaction;
        }

        else if (ms->treemap != 0 && (mem = tmalloc_small(ms, nb)) != 0) {
          check_malloced_chunk(ms, mem, nb);
          goto postaction;
        }
      }
    }
    else if (bytes >= MAX_REQUEST)
      nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
    else {
      nb = pad_request(bytes);
      if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
        check_malloced_chunk(ms, mem, nb);
        goto postaction;
      }
    }

    if (nb <= ms->dvsize) {
      size_t rsize = ms->dvsize - nb;
      mchunkptr p = ms->dv;
      if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
        mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
        ms->dvsize = rsize;
        set_size_and_pinuse_of_free_chunk(r, rsize);
        set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
      }
      else { /* exhaust dv */
        size_t dvs = ms->dvsize;
        ms->dvsize = 0;
        ms->dv = 0;
        set_inuse_and_pinuse(ms, p, dvs);
      }
      mem = chunk2mem(p);
      check_malloced_chunk(ms, mem, nb);
      goto postaction;
    }

    else if (nb < ms->topsize) { /* Split top */
      size_t rsize = ms->topsize -= nb;
      mchunkptr p = ms->top;
      mchunkptr r = ms->top = chunk_plus_offset(p, nb);
      r->head = rsize | PINUSE_BIT;
      set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
      mem = chunk2mem(p);
      check_top_chunk(ms, ms->top);
      check_malloced_chunk(ms, mem, nb);
      goto postaction;
    }

    mem = sys_alloc(ms, nb);
    POSTACTION(ms);
    if (mem == MAP_FAILED && weaken(__oom_hook)) {
      weaken(__oom_hook)(bytes);
    }
    return mem;

  postaction:
    POSTACTION(ms);
    return mem;
  }

  return 0;
}

void mspace_free(mspace msp, void* mem) {
  if (mem != 0) {
    mchunkptr p  = mem2chunk(mem);
#if FOOTERS
    mstate fm = get_mstate_for(p);
    (void)msp; /* placate people compiling -Wunused */
#else /* FOOTERS */
    mstate fm = (mstate)msp;
#endif /* FOOTERS */
    if (!ok_magic(fm)) {
      USAGE_ERROR_ACTION(fm, p);
      return;
    }
    if (!PREACTION(fm)) {
      check_inuse_chunk(fm, p);
      if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
        size_t psize = chunksize(p);
        mchunkptr next = chunk_plus_offset(p, psize);
        if (!pinuse(p)) {
          size_t prevsize = p->prev_foot;
          if (is_mmapped(p)) {
            psize += prevsize + MMAP_FOOT_PAD;
            if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
              fm->footprint -= psize;
            goto postaction;
          }
          else {
            mchunkptr prev = chunk_minus_offset(p, prevsize);
            psize += prevsize;
            p = prev;
            if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
              if (p != fm->dv) {
                unlink_chunk(fm, p, prevsize);
              }
              else if ((next->head & INUSE_BITS) == INUSE_BITS) {
                fm->dvsize = psize;
                set_free_with_pinuse(p, psize, next);
                goto postaction;
              }
            }
            else
              goto erroraction;
          }
        }

        if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
          if (!cinuse(next)) {  /* consolidate forward */
            if (next == fm->top) {
              size_t tsize = fm->topsize += psize;
              fm->top = p;
              p->head = tsize | PINUSE_BIT;
              if (p == fm->dv) {
                fm->dv = 0;
                fm->dvsize = 0;
              }
              if (should_trim(fm, tsize))
                sys_trim(fm, 0);
              goto postaction;
            }
            else if (next == fm->dv) {
              size_t dsize = fm->dvsize += psize;
              fm->dv = p;
              set_size_and_pinuse_of_free_chunk(p, dsize);
              goto postaction;
            }
            else {
              size_t nsize = chunksize(next);
              psize += nsize;
              unlink_chunk(fm, next, nsize);
              set_size_and_pinuse_of_free_chunk(p, psize);
              if (p == fm->dv) {
                fm->dvsize = psize;
                goto postaction;
              }
            }
          }
          else
            set_free_with_pinuse(p, psize, next);

          if (is_small(psize)) {
            insert_small_chunk(fm, p, psize);
            check_free_chunk(fm, p);
          }
          else {
            tchunkptr tp = (tchunkptr)p;
            insert_large_chunk(fm, tp, psize);
            check_free_chunk(fm, p);
            if (--fm->release_checks == 0)
              release_unused_segments(fm);
          }
          goto postaction;
        }
      }
    erroraction:
      USAGE_ERROR_ACTION(fm, p);
    postaction:
      POSTACTION(fm);
    }
  }
}

void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size) {
  void* mem;
  size_t req = 0;
  mstate ms = (mstate)msp;
  if (!ok_magic(ms)) {
    USAGE_ERROR_ACTION(ms,ms);
    return 0;
  }
  if (n_elements != 0) {
    req = n_elements * elem_size;
    if (((n_elements | elem_size) & ~(size_t)0xffff) &&
        (req / n_elements != elem_size))
      req = MAX_SIZE_T; /* force downstream failure on overflow */
  }
  mem = internal_malloc(ms, req);
  if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
    bzero(mem, req);
  return mem;
}

void* mspace_realloc(mspace msp, void* oldmem, size_t bytes) {
  void* mem = 0;
  if (oldmem == 0) {
    mem = mspace_malloc(msp, bytes);
  }
  else if (bytes >= MAX_REQUEST) {
    MALLOC_FAILURE_ACTION;
  }
#ifdef REALLOC_ZERO_BYTES_FREES
  else if (bytes == 0) {
    mspace_free(msp, oldmem);
  }
#endif /* REALLOC_ZERO_BYTES_FREES */
  else {
    size_t nb = request2size(bytes);
    mchunkptr oldp = mem2chunk(oldmem);
#if ! FOOTERS
    mstate m = (mstate)msp;
#else /* FOOTERS */
    mstate m = get_mstate_for(oldp);
    if (!ok_magic(m)) {
      USAGE_ERROR_ACTION(m, oldmem);
      return 0;
    }
#endif /* FOOTERS */
    if (!PREACTION(m)) {
      mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
      POSTACTION(m);
      if (newp != 0) {
        check_inuse_chunk(m, newp);
        mem = chunk2mem(newp);
      }
      else {
        mem = mspace_malloc(m, bytes);
        if (mem != 0) {
          size_t oc = chunksize(oldp) - overhead_for(oldp);
          memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
          mspace_free(m, oldmem);
        }
      }
    }
  }
  return mem;
}

void* mspace_realloc_in_place(mspace msp, void* oldmem, size_t bytes) {
  void* mem = 0;
  if (oldmem != 0) {
    if (bytes >= MAX_REQUEST) {
      MALLOC_FAILURE_ACTION;
    }
    else {
      size_t nb = request2size(bytes);
      mchunkptr oldp = mem2chunk(oldmem);
#if ! FOOTERS
      mstate m = (mstate)msp;
#else /* FOOTERS */
      mstate m = get_mstate_for(oldp);
      (void)msp; /* placate people compiling -Wunused */
      if (!ok_magic(m)) {
        USAGE_ERROR_ACTION(m, oldmem);
        return 0;
      }
#endif /* FOOTERS */
      if (!PREACTION(m)) {
        mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
        POSTACTION(m);
        if (newp == oldp) {
          check_inuse_chunk(m, newp);
          mem = oldmem;
        }
      }
    }
  }
  return mem;
}

void* mspace_memalign(mspace msp, size_t alignment, size_t bytes) {
  mstate ms = (mstate)msp;
  if (!ok_magic(ms)) {
    USAGE_ERROR_ACTION(ms,ms);
    return 0;
  }
  if (alignment <= MALLOC_ALIGNMENT)
    return mspace_malloc(msp, bytes);
  return internal_memalign(ms, alignment, bytes);
}

void** mspace_independent_calloc(mspace msp, size_t n_elements,
                                 size_t elem_size, void* chunks[]) {
  size_t sz = elem_size; /* serves as 1-element array */
  mstate ms = (mstate)msp;
  if (!ok_magic(ms)) {
    USAGE_ERROR_ACTION(ms,ms);
    return 0;
  }
  return ialloc(ms, n_elements, &sz, 3, chunks);
}

void** mspace_independent_comalloc(mspace msp, size_t n_elements,
                                   size_t sizes[], void* chunks[]) {
  mstate ms = (mstate)msp;
  if (!ok_magic(ms)) {
    USAGE_ERROR_ACTION(ms,ms);
    return 0;
  }
  return ialloc(ms, n_elements, sizes, 0, chunks);
}

size_t mspace_bulk_free(mspace msp, void* array[], size_t nelem) {
  return internal_bulk_free((mstate)msp, array, nelem);
}

#if MALLOC_INSPECT_ALL
void mspace_inspect_all(mspace msp,
                        void(*handler)(void *start,
                                       void *end,
                                       size_t used_bytes,
                                       void* callback_arg),
                        void* arg) {
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    if (!PREACTION(ms)) {
      internal_inspect_all(ms, handler, arg);
      POSTACTION(ms);
    }
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
}
#endif /* MALLOC_INSPECT_ALL */

int mspace_trim(mspace msp, size_t pad) {
  int result = 0;
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    if (!PREACTION(ms)) {
      result = sys_trim(ms, pad);
      POSTACTION(ms);
    }
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return result;
}

#if !NO_MALLOC_STATS
void mspace_malloc_stats(mspace msp) {
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    internal_malloc_stats(ms);
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
}
#endif /* NO_MALLOC_STATS */

size_t mspace_footprint(mspace msp) {
  size_t result = 0;
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    result = ms->footprint;
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return result;
}

size_t mspace_max_footprint(mspace msp) {
  size_t result = 0;
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    result = ms->max_footprint;
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return result;
}

size_t mspace_footprint_limit(mspace msp) {
  size_t result = 0;
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    size_t maf = ms->footprint_limit;
    result = (maf == 0) ? MAX_SIZE_T : maf;
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return result;
}

size_t mspace_set_footprint_limit(mspace msp, size_t bytes) {
  size_t result = 0;
  mstate ms = (mstate)msp;
  if (ok_magic(ms)) {
    if (bytes == 0)
      result = granularity_align(1); /* Use minimal size */
    if (bytes == MAX_SIZE_T)
      result = 0;                    /* disable */
    else
      result = granularity_align(bytes);
    ms->footprint_limit = result;
  }
  else {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return result;
}

#if !NO_MALLINFO
struct mallinfo mspace_mallinfo(mspace msp) {
  mstate ms = (mstate)msp;
  if (!ok_magic(ms)) {
    USAGE_ERROR_ACTION(ms,ms);
  }
  return internal_mallinfo(ms);
}
#endif /* NO_MALLINFO */

size_t mspace_usable_size(const void* mem) {
  if (mem != 0) {
    mchunkptr p = mem2chunk(mem);
    if (is_inuse(p))
      return chunksize(p) - overhead_for(p);
  }
  return 0;
}

int mspace_mallopt(int param_number, int value) {
  return change_mparam(param_number, value);
}

#endif /* MSPACES */