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  1. /*
  2.   Default header file for malloc-2.8.x, written by Doug Lea
  3.   and released to the public domain, as explained at
  4.   http://creativecommons.org/licenses/publicdomain.
  5.  
  6.   last update: Mon Aug 15 08:55:52 2005  Doug Lea  (dl at gee)
  7.  
  8.   This header is for ANSI C/C++ only.  You can set any of
  9.   the following #defines before including:
  10.  
  11.   * If USE_DL_PREFIX is defined, it is assumed that malloc.c
  12.     was also compiled with this option, so all routines
  13.     have names starting with "dl".
  14.  
  15.   * If HAVE_USR_INCLUDE_MALLOC_H is defined, it is assumed that this
  16.     file will be #included AFTER <malloc.h>. This is needed only if
  17.     your system defines a struct mallinfo that is incompatible with the
  18.     standard one declared here.  Otherwise, you can include this file
  19.     INSTEAD of your system system <malloc.h>.  At least on ANSI, all
  20.     declarations should be compatible with system versions
  21.  
  22.   * If MSPACES is defined, declarations for mspace versions are included.
  23. */
  24.  
  25. #ifndef MALLOC_280_H
  26. #define MALLOC_280_H
  27.  
  28. #ifdef __cplusplus
  29. extern "C" {
  30. #endif
  31.  
  32. #include <stddef.h>   /* for size_t */
  33.  
  34. #if !ONLY_MSPACES
  35.  
  36. #ifndef USE_DL_PREFIX
  37. #define dlcalloc               calloc
  38. #define dlfree                 free
  39. #define dlmalloc               malloc
  40. #define dlmemalign             memalign
  41. #define dlrealloc              realloc
  42. #define dlvalloc               valloc
  43. #define dlpvalloc              pvalloc
  44. #define dlmallinfo             mallinfo
  45. #define dlmallopt              mallopt
  46. #define dlmalloc_trim          malloc_trim
  47. #define dlmalloc_stats         malloc_stats
  48. #define dlmalloc_usable_size   malloc_usable_size
  49. #define dlmalloc_footprint     malloc_footprint
  50. #define dlindependent_calloc   independent_calloc
  51. #define dlindependent_comalloc independent_comalloc
  52. #endif /* USE_DL_PREFIX */
  53.  
  54.  
  55. /*
  56.   malloc(size_t n)
  57.   Returns a pointer to a newly allocated chunk of at least n bytes, or
  58.   null if no space is available, in which case errno is set to ENOMEM
  59.   on ANSI C systems.
  60.  
  61.   If n is zero, malloc returns a minimum-sized chunk. (The minimum
  62.   size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
  63.   systems.)  Note that size_t is an unsigned type, so calls with
  64.   arguments that would be negative if signed are interpreted as
  65.   requests for huge amounts of space, which will often fail. The
  66.   maximum supported value of n differs across systems, but is in all
  67.   cases less than the maximum representable value of a size_t.
  68. */
  69. void* dlmalloc(size_t);
  70.  
  71. /*
  72.   free(void* p)
  73.   Releases the chunk of memory pointed to by p, that had been previously
  74.   allocated using malloc or a related routine such as realloc.
  75.   It has no effect if p is null. If p was not malloced or already
  76.   freed, free(p) will by default cuase the current program to abort.
  77. */
  78. void  dlfree(void*);
  79.  
  80. /*
  81.   calloc(size_t n_elements, size_t element_size);
  82.   Returns a pointer to n_elements * element_size bytes, with all locations
  83.   set to zero.
  84. */
  85. void* dlcalloc(size_t, size_t);
  86.  
  87. /*
  88.   realloc(void* p, size_t n)
  89.   Returns a pointer to a chunk of size n that contains the same data
  90.   as does chunk p up to the minimum of (n, p's size) bytes, or null
  91.   if no space is available.
  92.  
  93.   The returned pointer may or may not be the same as p. The algorithm
  94.   prefers extending p in most cases when possible, otherwise it
  95.   employs the equivalent of a malloc-copy-free sequence.
  96.  
  97.   If p is null, realloc is equivalent to malloc.
  98.  
  99.   If space is not available, realloc returns null, errno is set (if on
  100.   ANSI) and p is NOT freed.
  101.  
  102.   if n is for fewer bytes than already held by p, the newly unused
  103.   space is lopped off and freed if possible.  realloc with a size
  104.   argument of zero (re)allocates a minimum-sized chunk.
  105.  
  106.   The old unix realloc convention of allowing the last-free'd chunk
  107.   to be used as an argument to realloc is not supported.
  108. */
  109.  
  110. void* dlrealloc(void*, size_t);
  111.  
  112. /*
  113.   memalign(size_t alignment, size_t n);
  114.   Returns a pointer to a newly allocated chunk of n bytes, aligned
  115.   in accord with the alignment argument.
  116.  
  117.   The alignment argument should be a power of two. If the argument is
  118.   not a power of two, the nearest greater power is used.
  119.   8-byte alignment is guaranteed by normal malloc calls, so don't
  120.   bother calling memalign with an argument of 8 or less.
  121.  
  122.   Overreliance on memalign is a sure way to fragment space.
  123. */
  124. void* dlmemalign(size_t, size_t);
  125.  
  126. /*
  127.   valloc(size_t n);
  128.   Equivalent to memalign(pagesize, n), where pagesize is the page
  129.   size of the system. If the pagesize is unknown, 4096 is used.
  130. */
  131. void* dlvalloc(size_t);
  132.  
  133. /*
  134.   mallopt(int parameter_number, int parameter_value)
  135.   Sets tunable parameters The format is to provide a
  136.   (parameter-number, parameter-value) pair.  mallopt then sets the
  137.   corresponding parameter to the argument value if it can (i.e., so
  138.   long as the value is meaningful), and returns 1 if successful else
  139.   0.  SVID/XPG/ANSI defines four standard param numbers for mallopt,
  140.   normally defined in malloc.h.  None of these are use in this malloc,
  141.   so setting them has no effect. But this malloc also supports other
  142.   options in mallopt:
  143.  
  144.   Symbol            param #  default    allowed param values
  145.   M_TRIM_THRESHOLD     -1   2*1024*1024   any   (-1U disables trimming)
  146.   M_GRANULARITY        -2     page size   any power of 2 >= page size
  147.   M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
  148. */
  149. int dlmallopt(int, int);
  150.  
  151. #define M_TRIM_THRESHOLD     (-1)
  152. #define M_GRANULARITY        (-2)
  153. #define M_MMAP_THRESHOLD     (-3)
  154.  
  155.  
  156. /*
  157.   malloc_footprint();
  158.   Returns the number of bytes obtained from the system.  The total
  159.   number of bytes allocated by malloc, realloc etc., is less than this
  160.   value. Unlike mallinfo, this function returns only a precomputed
  161.   result, so can be called frequently to monitor memory consumption.
  162.   Even if locks are otherwise defined, this function does not use them,
  163.   so results might not be up to date.
  164. */
  165. size_t dlmalloc_footprint();
  166.  
  167. #if !NO_MALLINFO
  168. /*
  169.   mallinfo()
  170.   Returns (by copy) a struct containing various summary statistics:
  171.  
  172.   arena:     current total non-mmapped bytes allocated from system
  173.   ordblks:   the number of free chunks
  174.   smblks:    always zero.
  175.   hblks:     current number of mmapped regions
  176.   hblkhd:    total bytes held in mmapped regions
  177.   usmblks:   the maximum total allocated space. This will be greater
  178.                 than current total if trimming has occurred.
  179.   fsmblks:   always zero
  180.   uordblks:  current total allocated space (normal or mmapped)
  181.   fordblks:  total free space
  182.   keepcost:  the maximum number of bytes that could ideally be released
  183.                back to system via malloc_trim. ("ideally" means that
  184.                it ignores page restrictions etc.)
  185.  
  186.   Because these fields are ints, but internal bookkeeping may
  187.   be kept as longs, the reported values may wrap around zero and
  188.   thus be inaccurate.
  189. */
  190. #ifndef HAVE_USR_INCLUDE_MALLOC_H
  191. #ifndef _MALLOC_H
  192. #ifndef MALLINFO_FIELD_TYPE
  193. #define MALLINFO_FIELD_TYPE size_t
  194. #endif /* MALLINFO_FIELD_TYPE */
  195. struct mallinfo {
  196.   MALLINFO_FIELD_TYPE arena;    /* non-mmapped space allocated from system */
  197.   MALLINFO_FIELD_TYPE ordblks;  /* number of free chunks */
  198.   MALLINFO_FIELD_TYPE smblks;   /* always 0 */
  199.   MALLINFO_FIELD_TYPE hblks;    /* always 0 */
  200.   MALLINFO_FIELD_TYPE hblkhd;   /* space in mmapped regions */
  201.   MALLINFO_FIELD_TYPE usmblks;  /* maximum total allocated space */
  202.   MALLINFO_FIELD_TYPE fsmblks;  /* always 0 */
  203.   MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
  204.   MALLINFO_FIELD_TYPE fordblks; /* total free space */
  205.   MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
  206. };
  207. #endif  /* _MALLOC_H */
  208. #endif  /* HAVE_USR_INCLUDE_MALLOC_H */
  209.  
  210. struct mallinfo dlmallinfo(void);
  211. #endif  /* NO_MALLINFO */
  212.  
  213. /*
  214.   independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
  215.  
  216.   independent_calloc is similar to calloc, but instead of returning a
  217.   single cleared space, it returns an array of pointers to n_elements
  218.   independent elements that can hold contents of size elem_size, each
  219.   of which starts out cleared, and can be independently freed,
  220.   realloc'ed etc. The elements are guaranteed to be adjacently
  221.   allocated (this is not guaranteed to occur with multiple callocs or
  222.   mallocs), which may also improve cache locality in some
  223.   applications.
  224.  
  225.   The "chunks" argument is optional (i.e., may be null, which is
  226.   probably the most typical usage). If it is null, the returned array
  227.   is itself dynamically allocated and should also be freed when it is
  228.   no longer needed. Otherwise, the chunks array must be of at least
  229.   n_elements in length. It is filled in with the pointers to the
  230.   chunks.
  231.  
  232.   In either case, independent_calloc returns this pointer array, or
  233.   null if the allocation failed.  If n_elements is zero and "chunks"
  234.   is null, it returns a chunk representing an array with zero elements
  235.   (which should be freed if not wanted).
  236.  
  237.   Each element must be individually freed when it is no longer
  238.   needed. If you'd like to instead be able to free all at once, you
  239.   should instead use regular calloc and assign pointers into this
  240.   space to represent elements.  (In this case though, you cannot
  241.   independently free elements.)
  242.  
  243.   independent_calloc simplifies and speeds up implementations of many
  244.   kinds of pools.  It may also be useful when constructing large data
  245.   structures that initially have a fixed number of fixed-sized nodes,
  246.   but the number is not known at compile time, and some of the nodes
  247.   may later need to be freed. For example:
  248.  
  249.   struct Node { int item; struct Node* next; };
  250.  
  251.   struct Node* build_list() {
  252.     struct Node** pool;
  253.     int n = read_number_of_nodes_needed();
  254.     if (n <= 0) return 0;
  255.     pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
  256.     if (pool == 0) die();
  257.     // organize into a linked list...
  258.     struct Node* first = pool[0];
  259.     for (i = 0; i < n-1; ++i)
  260.       pool[i]->next = pool[i+1];
  261.     free(pool);     // Can now free the array (or not, if it is needed later)
  262.     return first;
  263.   }
  264. */
  265. void** dlindependent_calloc(size_t, size_t, void**);
  266.  
  267. /*
  268.   independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
  269.  
  270.   independent_comalloc allocates, all at once, a set of n_elements
  271.   chunks with sizes indicated in the "sizes" array.    It returns
  272.   an array of pointers to these elements, each of which can be
  273.   independently freed, realloc'ed etc. The elements are guaranteed to
  274.   be adjacently allocated (this is not guaranteed to occur with
  275.   multiple callocs or mallocs), which may also improve cache locality
  276.   in some applications.
  277.  
  278.   The "chunks" argument is optional (i.e., may be null). If it is null
  279.   the returned array is itself dynamically allocated and should also
  280.   be freed when it is no longer needed. Otherwise, the chunks array
  281.   must be of at least n_elements in length. It is filled in with the
  282.   pointers to the chunks.
  283.  
  284.   In either case, independent_comalloc returns this pointer array, or
  285.   null if the allocation failed.  If n_elements is zero and chunks is
  286.   null, it returns a chunk representing an array with zero elements
  287.   (which should be freed if not wanted).
  288.  
  289.   Each element must be individually freed when it is no longer
  290.   needed. If you'd like to instead be able to free all at once, you
  291.   should instead use a single regular malloc, and assign pointers at
  292.   particular offsets in the aggregate space. (In this case though, you
  293.   cannot independently free elements.)
  294.  
  295.   independent_comallac differs from independent_calloc in that each
  296.   element may have a different size, and also that it does not
  297.   automatically clear elements.
  298.  
  299.   independent_comalloc can be used to speed up allocation in cases
  300.   where several structs or objects must always be allocated at the
  301.   same time.  For example:
  302.  
  303.   struct Head { ... }
  304.   struct Foot { ... }
  305.  
  306.   void send_message(char* msg) {
  307.     int msglen = strlen(msg);
  308.     size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
  309.     void* chunks[3];
  310.     if (independent_comalloc(3, sizes, chunks) == 0)
  311.       die();
  312.     struct Head* head = (struct Head*)(chunks[0]);
  313.     char*        body = (char*)(chunks[1]);
  314.     struct Foot* foot = (struct Foot*)(chunks[2]);
  315.     // ...
  316.   }
  317.  
  318.   In general though, independent_comalloc is worth using only for
  319.   larger values of n_elements. For small values, you probably won't
  320.   detect enough difference from series of malloc calls to bother.
  321.  
  322.   Overuse of independent_comalloc can increase overall memory usage,
  323.   since it cannot reuse existing noncontiguous small chunks that
  324.   might be available for some of the elements.
  325. */
  326. void** dlindependent_comalloc(size_t, size_t*, void**);
  327.  
  328.  
  329. /*
  330.   pvalloc(size_t n);
  331.   Equivalent to valloc(minimum-page-that-holds(n)), that is,
  332.   round up n to nearest pagesize.
  333.  */
  334. void*  dlpvalloc(size_t);
  335.  
  336. /*
  337.   malloc_trim(size_t pad);
  338.  
  339.   If possible, gives memory back to the system (via negative arguments
  340.   to sbrk) if there is unused memory at the `high' end of the malloc
  341.   pool or in unused MMAP segments. You can call this after freeing
  342.   large blocks of memory to potentially reduce the system-level memory
  343.   requirements of a program. However, it cannot guarantee to reduce
  344.   memory. Under some allocation patterns, some large free blocks of
  345.   memory will be locked between two used chunks, so they cannot be
  346.   given back to the system.
  347.  
  348.   The `pad' argument to malloc_trim represents the amount of free
  349.   trailing space to leave untrimmed. If this argument is zero, only
  350.   the minimum amount of memory to maintain internal data structures
  351.   will be left. Non-zero arguments can be supplied to maintain enough
  352.   trailing space to service future expected allocations without having
  353.   to re-obtain memory from the system.
  354.  
  355.   Malloc_trim returns 1 if it actually released any memory, else 0.
  356. */
  357. int  dlmalloc_trim(size_t);
  358.  
  359. /*
  360.   malloc_usable_size(void* p);
  361.  
  362.   Returns the number of bytes you can actually use in
  363.   an allocated chunk, which may be more than you requested (although
  364.   often not) due to alignment and minimum size constraints.
  365.   You can use this many bytes without worrying about
  366.   overwriting other allocated objects. This is not a particularly great
  367.   programming practice. malloc_usable_size can be more useful in
  368.   debugging and assertions, for example:
  369.  
  370.   p = malloc(n);
  371.   assert(malloc_usable_size(p) >= 256);
  372. */
  373. size_t dlmalloc_usable_size(void*);
  374.  
  375. /*
  376.   malloc_stats();
  377.   Prints on stderr the amount of space obtained from the system (both
  378.   via sbrk and mmap), the maximum amount (which may be more than
  379.   current if malloc_trim and/or munmap got called), and the current
  380.   number of bytes allocated via malloc (or realloc, etc) but not yet
  381.   freed. Note that this is the number of bytes allocated, not the
  382.   number requested. It will be larger than the number requested
  383.   because of alignment and bookkeeping overhead. Because it includes
  384.   alignment wastage as being in use, this figure may be greater than
  385.   zero even when no user-level chunks are allocated.
  386.  
  387.   The reported current and maximum system memory can be inaccurate if
  388.   a program makes other calls to system memory allocation functions
  389.   (normally sbrk) outside of malloc.
  390.  
  391.   malloc_stats prints only the most commonly interesting statistics.
  392.   More information can be obtained by calling mallinfo.
  393. */
  394. void  dlmalloc_stats();
  395.  
  396. #endif /* !ONLY_MSPACES */
  397.  
  398. #if MSPACES
  399.  
  400. /*
  401.   mspace is an opaque type representing an independent
  402.   region of space that supports mspace_malloc, etc.
  403. */
  404. typedef void* mspace;
  405.  
  406. /*
  407.   create_mspace creates and returns a new independent space with the
  408.   given initial capacity, or, if 0, the default granularity size.  It
  409.   returns null if there is no system memory available to create the
  410.   space.  If argument locked is non-zero, the space uses a separate
  411.   lock to control access. The capacity of the space will grow
  412.   dynamically as needed to service mspace_malloc requests.  You can
  413.   control the sizes of incremental increases of this space by
  414.   compiling with a different DEFAULT_GRANULARITY or dynamically
  415.   setting with mallopt(M_GRANULARITY, value).
  416. */
  417. mspace create_mspace(size_t capacity, int locked);
  418.  
  419. /*
  420.   destroy_mspace destroys the given space, and attempts to return all
  421.   of its memory back to the system, returning the total number of
  422.   bytes freed. After destruction, the results of access to all memory
  423.   used by the space become undefined.
  424. */
  425. size_t destroy_mspace(mspace msp);
  426.  
  427. /*
  428.   create_mspace_with_base uses the memory supplied as the initial base
  429.   of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
  430.   space is used for bookkeeping, so the capacity must be at least this
  431.   large. (Otherwise 0 is returned.) When this initial space is
  432.   exhausted, additional memory will be obtained from the system.
  433.   Destroying this space will deallocate all additionally allocated
  434.   space (if possible) but not the initial base.
  435. */
  436. mspace create_mspace_with_base(void* base, size_t capacity, int locked);
  437.  
  438. /*
  439.   mspace_malloc behaves as malloc, but operates within
  440.   the given space.
  441. */
  442. void* mspace_malloc(mspace msp, size_t bytes);
  443.  
  444. /*
  445.   mspace_free behaves as free, but operates within
  446.   the given space.
  447.  
  448.   If compiled with FOOTERS==1, mspace_free is not actually needed.
  449.   free may be called instead of mspace_free because freed chunks from
  450.   any space are handled by their originating spaces.
  451. */
  452. void mspace_free(mspace msp, void* mem);
  453.  
  454. /*
  455.   mspace_realloc behaves as realloc, but operates within
  456.   the given space.
  457.  
  458.   If compiled with FOOTERS==1, mspace_realloc is not actually
  459.   needed.  realloc may be called instead of mspace_realloc because
  460.   realloced chunks from any space are handled by their originating
  461.   spaces.
  462. */
  463. void* mspace_realloc(mspace msp, void* mem, size_t newsize);
  464.  
  465. /*
  466.   mspace_calloc behaves as calloc, but operates within
  467.   the given space.
  468. */
  469. void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
  470.  
  471. /*
  472.   mspace_memalign behaves as memalign, but operates within
  473.   the given space.
  474. */
  475. void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
  476.  
  477. /*
  478.   mspace_independent_calloc behaves as independent_calloc, but
  479.   operates within the given space.
  480. */
  481. void** mspace_independent_calloc(mspace msp, size_t n_elements,
  482.                                  size_t elem_size, void* chunks[]);
  483.  
  484. /*
  485.   mspace_independent_comalloc behaves as independent_comalloc, but
  486.   operates within the given space.
  487. */
  488. void** mspace_independent_comalloc(mspace msp, size_t n_elements,
  489.                                    size_t sizes[], void* chunks[]);
  490.  
  491. /*
  492.   mspace_footprint() returns the number of bytes obtained from the
  493.   system for this space.
  494. */
  495. size_t mspace_footprint(mspace msp);
  496.  
  497.  
  498. #if !NO_MALLINFO
  499. /*
  500.   mspace_mallinfo behaves as mallinfo, but reports properties of
  501.   the given space.
  502. */
  503. struct mallinfo mspace_mallinfo(mspace msp);
  504. #endif /* NO_MALLINFO */
  505.  
  506. /*
  507.   mspace_malloc_stats behaves as malloc_stats, but reports
  508.   properties of the given space.
  509. */
  510. void mspace_malloc_stats(mspace msp);
  511.  
  512. /*
  513.   mspace_trim behaves as malloc_trim, but
  514.   operates within the given space.
  515. */
  516. int mspace_trim(mspace msp, size_t pad);
  517.  
  518. /*
  519.   An alias for mallopt.
  520. */
  521. int mspace_mallopt(int, int);
  522.  
  523. #endif  /* MSPACES */
  524.  
  525. #ifdef __cplusplus
  526. };  /* end of extern "C" */
  527. #endif
  528.  
  529. #endif /* MALLOC_280_H */
  530.