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src/judy-1.0.5/test/malloc-pre2.8a.c  view on Meta::CPAN

  long as the value is meaningful), and returns 1 if successful else
  0.  SVID/XPG/ANSI defines four standard param numbers for mallopt,
  normally defined in malloc.h.  Only one of these (M_MXFAST) is used
  in this malloc. The others (M_NLBLKS, M_GRAIN, M_KEEP) don't apply,
  so setting them has no effect. But this malloc also supports four
  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_MXFAST          1         64         0-64  (0 disables fastbins)
  M_TRIM_THRESHOLD -1         256*1024   any   (-1U disables trimming)
  M_TOP_PAD        -2         0          any  
  M_MMAP_THRESHOLD -3         256*1024   any   (or 0 if no MMAP support)
  M_MMAP_MAX       -4         65536      any   (0 disables use of mmap)
*/
int      public_mALLOPt(int, int);


/*
  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:    the number of fastbin blocks (i.e., small chunks that
               have been freed but not use resused or consolidated)
  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:   total bytes held in fastbin blocks 
  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.
*/
struct mallinfo public_mALLINFo(void);

/*
  independent_calloc(size_t n_elements, size_t element_size, Void_t* 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 individually freed when it is no longer
  needed. If you'd like to instead be able to free all at once, you
  should instead use regular calloc and assign pointers into this
  space to represent elements.  (In this case though, you cannot
  independently free elements.)
  
  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;
  }
*/
Void_t** public_iCALLOc(size_t, size_t, Void_t**);

/*
  independent_comalloc(size_t n_elements, size_t sizes[], Void_t* 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 individually freed when it is no longer
  needed. If you'd like to instead be able to free all at once, you
  should instead use a single regular malloc, and assign pointers at
  particular offsets in the aggregate space. (In this case though, you 
  cannot independently free elements.)

  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.
*/
Void_t** public_iCOMALLOc(size_t, size_t*, Void_t**);


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

/*
  cfree(Void_t* p);
  Equivalent to free(p).

  cfree is needed/defined on some systems that pair it with calloc,
  for odd historical reasons (such as: cfree is used in example 

src/judy-1.0.5/test/malloc-pre2.8a.c  view on Meta::CPAN

}

/*
  ------------------------------ cfree ------------------------------
*/

void cFREe(Void_t *mem) {
  fREe(mem);
}

/*
  ------------------------- independent_calloc -------------------------
*/


Void_t** iCALLOc(size_t n_elements, size_t elem_size, Void_t* chunks[]) {
  size_t sz = elem_size; /* serves as 1-element array */
  /* opts arg of 3 means all elements are same size, and should be cleared */
  return iALLOc(n_elements, &sz, 3, chunks);
}

/*
  ------------------------- independent_comalloc -------------------------
*/

Void_t** iCOMALLOc(size_t n_elements, size_t sizes[], Void_t* chunks[]) {
  return iALLOc(n_elements, sizes, 0, chunks);
}


/*
  ------------------------------ ialloc ------------------------------
  ialloc provides 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_t** iALLOc(size_t n_elements, 
                       size_t* sizes,  
                       int opts,
                       Void_t* chunks[]) {
  mstate av = get_malloc_state();
  INTERNAL_SIZE_T element_size;   /* chunksize of each element, if all same */
  INTERNAL_SIZE_T contents_size;  /* total size of elements */
  INTERNAL_SIZE_T array_size;     /* request size of pointer array */
  Void_t*         mem;            /* malloced aggregate space */
  mchunkptr       p;              /* corresponding chunk */
  CHUNK_SIZE_T remainder_size; /* remaining bytes while splitting */
  Void_t**        marray;         /* either "chunks" or malloced ptr array */
  mchunkptr       array_chunk;    /* chunk for malloced ptr array */
  unsigned int    mprops;         /* to disable mmap */
  CHUNK_SIZE_T size;           
  size_t          i;

  ensure_initialization(av);

  /* 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_t**) mALLOc(0);
    marray = 0;
    array_size = request2size(n_elements * (sizeof(Void_t*)));
  }

  /* 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]);     
  }

  /* subtract out alignment bytes from total to minimize overallocation */
  size = contents_size + array_size - MALLOC_ALIGN_MASK;
  
  /* 
     Allocate the aggregate chunk.
     But first disable mmap so malloc won't use it, since
     we would not be able to later free/realloc space internal
     to a segregated mmap region.
 */
  
  mprops = av->sysctl;   /* disable mmap */
  disable_mmap(av);
  mem = mALLOc(size);
  av->sysctl = mprops; /* reset mmap */
  if (mem == 0) 
    return 0;

  p = mem2chunk(mem);
  assert(!chunk_is_mmapped(p)); 
  remainder_size = chunksize(p);


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

  /* If not provided, allocate the pointer array as final part of chunk */
  if (marray == 0) {
    array_chunk = chunk_at_offset(p, contents_size);
    marray = (Void_t**) (chunk2mem(array_chunk));
    set_head(array_chunk, (remainder_size - contents_size) | PREV_INUSE);
    remainder_size = contents_size;
  }