Panda3D

dlmalloc.h

00001 /*
00002   Default header file for malloc-2.8.x, written by Doug Lea
00003   and released to the public domain, as explained at
00004   http://creativecommons.org/licenses/publicdomain. 
00005  
00006   last update: Mon Aug 15 08:55:52 2005  Doug Lea  (dl at gee)
00007 
00008   This header is for ANSI C/C++ only.  You can set any of
00009   the following #defines before including:
00010 
00011   * If USE_DL_PREFIX is defined, it is assumed that malloc.c 
00012     was also compiled with this option, so all routines
00013     have names starting with "dl".
00014 
00015   * If HAVE_USR_INCLUDE_MALLOC_H is defined, it is assumed that this
00016     file will be #included AFTER <malloc.h>. This is needed only if
00017     your system defines a struct mallinfo that is incompatible with the
00018     standard one declared here.  Otherwise, you can include this file
00019     INSTEAD of your system system <malloc.h>.  At least on ANSI, all
00020     declarations should be compatible with system versions
00021 
00022   * If MSPACES is defined, declarations for mspace versions are included.
00023 */
00024 
00025 #ifndef MALLOC_280_H
00026 #define MALLOC_280_H
00027 
00028 #ifdef __cplusplus
00029 extern "C" {
00030 #endif
00031 
00032 #include <stddef.h>   /* for size_t */
00033 
00034 #if !ONLY_MSPACES
00035 
00036 #ifndef USE_DL_PREFIX
00037 #define dlcalloc               calloc
00038 #define dlfree                 free
00039 #define dlmalloc               malloc
00040 #define dlmemalign             memalign
00041 #define dlrealloc              realloc
00042 #define dlvalloc               valloc
00043 #define dlpvalloc              pvalloc
00044 #define dlmallinfo             mallinfo
00045 #define dlmallopt              mallopt
00046 #define dlmalloc_trim          malloc_trim
00047 #define dlmalloc_stats         malloc_stats
00048 #define dlmalloc_usable_size   malloc_usable_size
00049 #define dlmalloc_footprint     malloc_footprint
00050 #define dlindependent_calloc   independent_calloc
00051 #define dlindependent_comalloc independent_comalloc
00052 #endif /* USE_DL_PREFIX */
00053 
00054 
00055 /*
00056   malloc(size_t n)
00057   Returns a pointer to a newly allocated chunk of at least n bytes, or
00058   null if no space is available, in which case errno is set to ENOMEM
00059   on ANSI C systems.
00060 
00061   If n is zero, malloc returns a minimum-sized chunk. (The minimum
00062   size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
00063   systems.)  Note that size_t is an unsigned type, so calls with
00064   arguments that would be negative if signed are interpreted as
00065   requests for huge amounts of space, which will often fail. The
00066   maximum supported value of n differs across systems, but is in all
00067   cases less than the maximum representable value of a size_t.
00068 */
00069 void* dlmalloc(size_t);
00070 
00071 /*
00072   free(void* p)
00073   Releases the chunk of memory pointed to by p, that had been previously
00074   allocated using malloc or a related routine such as realloc.
00075   It has no effect if p is null. If p was not malloced or already
00076   freed, free(p) will by default cuase the current program to abort.
00077 */
00078 void  dlfree(void*);
00079 
00080 /*
00081   calloc(size_t n_elements, size_t element_size);
00082   Returns a pointer to n_elements * element_size bytes, with all locations
00083   set to zero.
00084 */
00085 void* dlcalloc(size_t, size_t);
00086 
00087 /*
00088   realloc(void* p, size_t n)
00089   Returns a pointer to a chunk of size n that contains the same data
00090   as does chunk p up to the minimum of (n, p's size) bytes, or null
00091   if no space is available.
00092 
00093   The returned pointer may or may not be the same as p. The algorithm
00094   prefers extending p in most cases when possible, otherwise it
00095   employs the equivalent of a malloc-copy-free sequence.
00096 
00097   If p is null, realloc is equivalent to malloc.
00098 
00099   If space is not available, realloc returns null, errno is set (if on
00100   ANSI) and p is NOT freed.
00101 
00102   if n is for fewer bytes than already held by p, the newly unused
00103   space is lopped off and freed if possible.  realloc with a size
00104   argument of zero (re)allocates a minimum-sized chunk.
00105 
00106   The old unix realloc convention of allowing the last-free'd chunk
00107   to be used as an argument to realloc is not supported.
00108 */
00109 
00110 void* dlrealloc(void*, size_t);
00111 
00112 /*
00113   memalign(size_t alignment, size_t n);
00114   Returns a pointer to a newly allocated chunk of n bytes, aligned
00115   in accord with the alignment argument.
00116 
00117   The alignment argument should be a power of two. If the argument is
00118   not a power of two, the nearest greater power is used.
00119   8-byte alignment is guaranteed by normal malloc calls, so don't
00120   bother calling memalign with an argument of 8 or less.
00121 
00122   Overreliance on memalign is a sure way to fragment space.
00123 */
00124 void* dlmemalign(size_t, size_t);
00125 
00126 /*
00127   valloc(size_t n);
00128   Equivalent to memalign(pagesize, n), where pagesize is the page
00129   size of the system. If the pagesize is unknown, 4096 is used.
00130 */
00131 void* dlvalloc(size_t);
00132 
00133 /*
00134   mallopt(int parameter_number, int parameter_value)
00135   Sets tunable parameters The format is to provide a
00136   (parameter-number, parameter-value) pair.  mallopt then sets the
00137   corresponding parameter to the argument value if it can (i.e., so
00138   long as the value is meaningful), and returns 1 if successful else
00139   0.  SVID/XPG/ANSI defines four standard param numbers for mallopt,
00140   normally defined in malloc.h.  None of these are use in this malloc,
00141   so setting them has no effect. But this malloc also supports other
00142   options in mallopt:
00143 
00144   Symbol            param #  default    allowed param values
00145   M_TRIM_THRESHOLD     -1   2*1024*1024   any   (-1U disables trimming)
00146   M_GRANULARITY        -2     page size   any power of 2 >= page size
00147   M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
00148 */
00149 int dlmallopt(int, int);
00150 
00151 #define M_TRIM_THRESHOLD     (-1)
00152 #define M_GRANULARITY        (-2)
00153 #define M_MMAP_THRESHOLD     (-3)
00154 
00155 
00156 /*
00157   malloc_footprint();
00158   Returns the number of bytes obtained from the system.  The total
00159   number of bytes allocated by malloc, realloc etc., is less than this
00160   value. Unlike mallinfo, this function returns only a precomputed
00161   result, so can be called frequently to monitor memory consumption.
00162   Even if locks are otherwise defined, this function does not use them,
00163   so results might not be up to date.
00164 */
00165 size_t dlmalloc_footprint();
00166 
00167 #if !NO_MALLINFO
00168 /*
00169   mallinfo()
00170   Returns (by copy) a struct containing various summary statistics:
00171 
00172   arena:     current total non-mmapped bytes allocated from system
00173   ordblks:   the number of free chunks
00174   smblks:    always zero.
00175   hblks:     current number of mmapped regions
00176   hblkhd:    total bytes held in mmapped regions
00177   usmblks:   the maximum total allocated space. This will be greater
00178                 than current total if trimming has occurred.
00179   fsmblks:   always zero
00180   uordblks:  current total allocated space (normal or mmapped)
00181   fordblks:  total free space
00182   keepcost:  the maximum number of bytes that could ideally be released
00183                back to system via malloc_trim. ("ideally" means that
00184                it ignores page restrictions etc.)
00185 
00186   Because these fields are ints, but internal bookkeeping may
00187   be kept as longs, the reported values may wrap around zero and
00188   thus be inaccurate.
00189 */
00190 #ifndef HAVE_USR_INCLUDE_MALLOC_H
00191 #ifndef _MALLOC_H
00192 #ifndef MALLINFO_FIELD_TYPE
00193 #define MALLINFO_FIELD_TYPE size_t
00194 #endif /* MALLINFO_FIELD_TYPE */
00195 struct mallinfo {
00196   MALLINFO_FIELD_TYPE arena;    /* non-mmapped space allocated from system */
00197   MALLINFO_FIELD_TYPE ordblks;  /* number of free chunks */
00198   MALLINFO_FIELD_TYPE smblks;   /* always 0 */
00199   MALLINFO_FIELD_TYPE hblks;    /* always 0 */
00200   MALLINFO_FIELD_TYPE hblkhd;   /* space in mmapped regions */
00201   MALLINFO_FIELD_TYPE usmblks;  /* maximum total allocated space */
00202   MALLINFO_FIELD_TYPE fsmblks;  /* always 0 */
00203   MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
00204   MALLINFO_FIELD_TYPE fordblks; /* total free space */
00205   MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
00206 };
00207 #endif  /* _MALLOC_H */
00208 #endif  /* HAVE_USR_INCLUDE_MALLOC_H */
00209 
00210 struct mallinfo dlmallinfo(void);
00211 #endif  /* NO_MALLINFO */
00212 
00213 /*
00214   independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
00215 
00216   independent_calloc is similar to calloc, but instead of returning a
00217   single cleared space, it returns an array of pointers to n_elements
00218   independent elements that can hold contents of size elem_size, each
00219   of which starts out cleared, and can be independently freed,
00220   realloc'ed etc. The elements are guaranteed to be adjacently
00221   allocated (this is not guaranteed to occur with multiple callocs or
00222   mallocs), which may also improve cache locality in some
00223   applications.
00224 
00225   The "chunks" argument is optional (i.e., may be null, which is
00226   probably the most typical usage). If it is null, the returned array
00227   is itself dynamically allocated and should also be freed when it is
00228   no longer needed. Otherwise, the chunks array must be of at least
00229   n_elements in length. It is filled in with the pointers to the
00230   chunks.
00231 
00232   In either case, independent_calloc returns this pointer array, or
00233   null if the allocation failed.  If n_elements is zero and "chunks"
00234   is null, it returns a chunk representing an array with zero elements
00235   (which should be freed if not wanted).
00236 
00237   Each element must be individually freed when it is no longer
00238   needed. If you'd like to instead be able to free all at once, you
00239   should instead use regular calloc and assign pointers into this
00240   space to represent elements.  (In this case though, you cannot
00241   independently free elements.)
00242 
00243   independent_calloc simplifies and speeds up implementations of many
00244   kinds of pools.  It may also be useful when constructing large data
00245   structures that initially have a fixed number of fixed-sized nodes,
00246   but the number is not known at compile time, and some of the nodes
00247   may later need to be freed. For example:
00248 
00249   struct Node { int item; struct Node* next; };
00250 
00251   struct Node* build_list() {
00252     struct Node** pool;
00253     int n = read_number_of_nodes_needed();
00254     if (n <= 0) return 0;
00255     pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
00256     if (pool == 0) die();
00257     // organize into a linked list...
00258     struct Node* first = pool[0];
00259     for (i = 0; i < n-1; ++i)
00260       pool[i]->next = pool[i+1];
00261     free(pool);     // Can now free the array (or not, if it is needed later)
00262     return first;
00263   }
00264 */
00265 void** dlindependent_calloc(size_t, size_t, void**);
00266 
00267 /*
00268   independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
00269 
00270   independent_comalloc allocates, all at once, a set of n_elements
00271   chunks with sizes indicated in the "sizes" array.    It returns
00272   an array of pointers to these elements, each of which can be
00273   independently freed, realloc'ed etc. The elements are guaranteed to
00274   be adjacently allocated (this is not guaranteed to occur with
00275   multiple callocs or mallocs), which may also improve cache locality
00276   in some applications.
00277 
00278   The "chunks" argument is optional (i.e., may be null). If it is null
00279   the returned array is itself dynamically allocated and should also
00280   be freed when it is no longer needed. Otherwise, the chunks array
00281   must be of at least n_elements in length. It is filled in with the
00282   pointers to the chunks.
00283 
00284   In either case, independent_comalloc returns this pointer array, or
00285   null if the allocation failed.  If n_elements is zero and chunks is
00286   null, it returns a chunk representing an array with zero elements
00287   (which should be freed if not wanted).
00288 
00289   Each element must be individually freed when it is no longer
00290   needed. If you'd like to instead be able to free all at once, you
00291   should instead use a single regular malloc, and assign pointers at
00292   particular offsets in the aggregate space. (In this case though, you
00293   cannot independently free elements.)
00294 
00295   independent_comallac differs from independent_calloc in that each
00296   element may have a different size, and also that it does not
00297   automatically clear elements.
00298 
00299   independent_comalloc can be used to speed up allocation in cases
00300   where several structs or objects must always be allocated at the
00301   same time.  For example:
00302 
00303   struct Head { ... }
00304   struct Foot { ... }
00305 
00306   void send_message(char* msg) {
00307     int msglen = strlen(msg);
00308     size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
00309     void* chunks[3];
00310     if (independent_comalloc(3, sizes, chunks) == 0)
00311       die();
00312     struct Head* head = (struct Head*)(chunks[0]);
00313     char*        body = (char*)(chunks[1]);
00314     struct Foot* foot = (struct Foot*)(chunks[2]);
00315     // ...
00316   }
00317 
00318   In general though, independent_comalloc is worth using only for
00319   larger values of n_elements. For small values, you probably won't
00320   detect enough difference from series of malloc calls to bother.
00321 
00322   Overuse of independent_comalloc can increase overall memory usage,
00323   since it cannot reuse existing noncontiguous small chunks that
00324   might be available for some of the elements.
00325 */
00326 void** dlindependent_comalloc(size_t, size_t*, void**);
00327 
00328 
00329 /*
00330   pvalloc(size_t n);
00331   Equivalent to valloc(minimum-page-that-holds(n)), that is,
00332   round up n to nearest pagesize.
00333  */
00334 void*  dlpvalloc(size_t);
00335 
00336 /*
00337   malloc_trim(size_t pad);
00338 
00339   If possible, gives memory back to the system (via negative arguments
00340   to sbrk) if there is unused memory at the `high' end of the malloc
00341   pool or in unused MMAP segments. You can call this after freeing
00342   large blocks of memory to potentially reduce the system-level memory
00343   requirements of a program. However, it cannot guarantee to reduce
00344   memory. Under some allocation patterns, some large free blocks of
00345   memory will be locked between two used chunks, so they cannot be
00346   given back to the system.
00347 
00348   The `pad' argument to malloc_trim represents the amount of free
00349   trailing space to leave untrimmed. If this argument is zero, only
00350   the minimum amount of memory to maintain internal data structures
00351   will be left. Non-zero arguments can be supplied to maintain enough
00352   trailing space to service future expected allocations without having
00353   to re-obtain memory from the system.
00354 
00355   Malloc_trim returns 1 if it actually released any memory, else 0.
00356 */
00357 int  dlmalloc_trim(size_t);
00358 
00359 /*
00360   malloc_usable_size(void* p);
00361 
00362   Returns the number of bytes you can actually use in
00363   an allocated chunk, which may be more than you requested (although
00364   often not) due to alignment and minimum size constraints.
00365   You can use this many bytes without worrying about
00366   overwriting other allocated objects. This is not a particularly great
00367   programming practice. malloc_usable_size can be more useful in
00368   debugging and assertions, for example:
00369 
00370   p = malloc(n);
00371   assert(malloc_usable_size(p) >= 256);
00372 */
00373 size_t dlmalloc_usable_size(void*);
00374 
00375 /*
00376   malloc_stats();
00377   Prints on stderr the amount of space obtained from the system (both
00378   via sbrk and mmap), the maximum amount (which may be more than
00379   current if malloc_trim and/or munmap got called), and the current
00380   number of bytes allocated via malloc (or realloc, etc) but not yet
00381   freed. Note that this is the number of bytes allocated, not the
00382   number requested. It will be larger than the number requested
00383   because of alignment and bookkeeping overhead. Because it includes
00384   alignment wastage as being in use, this figure may be greater than
00385   zero even when no user-level chunks are allocated.
00386 
00387   The reported current and maximum system memory can be inaccurate if
00388   a program makes other calls to system memory allocation functions
00389   (normally sbrk) outside of malloc.
00390 
00391   malloc_stats prints only the most commonly interesting statistics.
00392   More information can be obtained by calling mallinfo.
00393 */
00394 void  dlmalloc_stats();
00395 
00396 #endif /* !ONLY_MSPACES */
00397 
00398 #if MSPACES
00399 
00400 /*
00401   mspace is an opaque type representing an independent
00402   region of space that supports mspace_malloc, etc.
00403 */
00404 typedef void* mspace;
00405 
00406 /*
00407   create_mspace creates and returns a new independent space with the
00408   given initial capacity, or, if 0, the default granularity size.  It
00409   returns null if there is no system memory available to create the
00410   space.  If argument locked is non-zero, the space uses a separate
00411   lock to control access. The capacity of the space will grow
00412   dynamically as needed to service mspace_malloc requests.  You can
00413   control the sizes of incremental increases of this space by
00414   compiling with a different DEFAULT_GRANULARITY or dynamically
00415   setting with mallopt(M_GRANULARITY, value).
00416 */
00417 mspace create_mspace(size_t capacity, int locked);
00418 
00419 /*
00420   destroy_mspace destroys the given space, and attempts to return all
00421   of its memory back to the system, returning the total number of
00422   bytes freed. After destruction, the results of access to all memory
00423   used by the space become undefined.
00424 */
00425 size_t destroy_mspace(mspace msp);
00426 
00427 /*
00428   create_mspace_with_base uses the memory supplied as the initial base
00429   of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
00430   space is used for bookkeeping, so the capacity must be at least this
00431   large. (Otherwise 0 is returned.) When this initial space is
00432   exhausted, additional memory will be obtained from the system.
00433   Destroying this space will deallocate all additionally allocated
00434   space (if possible) but not the initial base.
00435 */
00436 mspace create_mspace_with_base(void* base, size_t capacity, int locked);
00437 
00438 /*
00439   mspace_malloc behaves as malloc, but operates within
00440   the given space.
00441 */
00442 void* mspace_malloc(mspace msp, size_t bytes);
00443 
00444 /*
00445   mspace_free behaves as free, but operates within
00446   the given space.
00447 
00448   If compiled with FOOTERS==1, mspace_free is not actually needed.
00449   free may be called instead of mspace_free because freed chunks from
00450   any space are handled by their originating spaces.
00451 */
00452 void mspace_free(mspace msp, void* mem);
00453 
00454 /*
00455   mspace_realloc behaves as realloc, but operates within
00456   the given space.
00457 
00458   If compiled with FOOTERS==1, mspace_realloc is not actually
00459   needed.  realloc may be called instead of mspace_realloc because
00460   realloced chunks from any space are handled by their originating
00461   spaces.
00462 */
00463 void* mspace_realloc(mspace msp, void* mem, size_t newsize);
00464 
00465 /*
00466   mspace_calloc behaves as calloc, but operates within
00467   the given space.
00468 */
00469 void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
00470 
00471 /*
00472   mspace_memalign behaves as memalign, but operates within
00473   the given space.
00474 */
00475 void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
00476 
00477 /*
00478   mspace_independent_calloc behaves as independent_calloc, but
00479   operates within the given space.
00480 */
00481 void** mspace_independent_calloc(mspace msp, size_t n_elements,
00482                                  size_t elem_size, void* chunks[]);
00483 
00484 /*
00485   mspace_independent_comalloc behaves as independent_comalloc, but
00486   operates within the given space.
00487 */
00488 void** mspace_independent_comalloc(mspace msp, size_t n_elements,
00489                                    size_t sizes[], void* chunks[]);
00490 
00491 /*
00492   mspace_footprint() returns the number of bytes obtained from the
00493   system for this space.
00494 */
00495 size_t mspace_footprint(mspace msp);
00496 
00497 
00498 #if !NO_MALLINFO
00499 /*
00500   mspace_mallinfo behaves as mallinfo, but reports properties of
00501   the given space.
00502 */
00503 struct mallinfo mspace_mallinfo(mspace msp);
00504 #endif /* NO_MALLINFO */
00505 
00506 /*
00507   mspace_malloc_stats behaves as malloc_stats, but reports
00508   properties of the given space.
00509 */
00510 void mspace_malloc_stats(mspace msp);
00511 
00512 /*
00513   mspace_trim behaves as malloc_trim, but
00514   operates within the given space.
00515 */
00516 int mspace_trim(mspace msp, size_t pad);
00517 
00518 /*
00519   An alias for mallopt.
00520 */
00521 int mspace_mallopt(int, int);
00522 
00523 #endif  /* MSPACES */
00524 
00525 #ifdef __cplusplus
00526 };  /* end of extern "C" */
00527 #endif
00528 
00529 #endif /* MALLOC_280_H */
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