xref: /openbmc/u-boot/include/malloc.h (revision 4e43b2e8)
1 /*
2   A version of malloc/free/realloc written by Doug Lea and released to the
3   public domain.  Send questions/comments/complaints/performance data
4   to dl@cs.oswego.edu
5 
6 * VERSION 2.6.6  Sun Mar  5 19:10:03 2000  Doug Lea  (dl at gee)
7 
8    Note: There may be an updated version of this malloc obtainable at
9 	   ftp://g.oswego.edu/pub/misc/malloc.c
10 	 Check before installing!
11 
12 * Why use this malloc?
13 
14   This is not the fastest, most space-conserving, most portable, or
15   most tunable malloc ever written. However it is among the fastest
16   while also being among the most space-conserving, portable and tunable.
17   Consistent balance across these factors results in a good general-purpose
18   allocator. For a high-level description, see
19      http://g.oswego.edu/dl/html/malloc.html
20 
21 * Synopsis of public routines
22 
23   (Much fuller descriptions are contained in the program documentation below.)
24 
25   malloc(size_t n);
26      Return a pointer to a newly allocated chunk of at least n bytes, or null
27      if no space is available.
28   free(Void_t* p);
29      Release the chunk of memory pointed to by p, or no effect if p is null.
30   realloc(Void_t* p, size_t n);
31      Return a pointer to a chunk of size n that contains the same data
32      as does chunk p up to the minimum of (n, p's size) bytes, or null
33      if no space is available. The returned pointer may or may not be
34      the same as p. If p is null, equivalent to malloc.  Unless the
35      #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
36      size argument of zero (re)allocates a minimum-sized chunk.
37   memalign(size_t alignment, size_t n);
38      Return a pointer to a newly allocated chunk of n bytes, aligned
39      in accord with the alignment argument, which must be a power of
40      two.
41   valloc(size_t n);
42      Equivalent to memalign(pagesize, n), where pagesize is the page
43      size of the system (or as near to this as can be figured out from
44      all the includes/defines below.)
45   pvalloc(size_t n);
46      Equivalent to valloc(minimum-page-that-holds(n)), that is,
47      round up n to nearest pagesize.
48   calloc(size_t unit, size_t quantity);
49      Returns a pointer to quantity * unit bytes, with all locations
50      set to zero.
51   cfree(Void_t* p);
52      Equivalent to free(p).
53   malloc_trim(size_t pad);
54      Release all but pad bytes of freed top-most memory back
55      to the system. Return 1 if successful, else 0.
56   malloc_usable_size(Void_t* p);
57      Report the number usable allocated bytes associated with allocated
58      chunk p. This may or may not report more bytes than were requested,
59      due to alignment and minimum size constraints.
60   malloc_stats();
61      Prints brief summary statistics on stderr.
62   mallinfo()
63      Returns (by copy) a struct containing various summary statistics.
64   mallopt(int parameter_number, int parameter_value)
65      Changes one of the tunable parameters described below. Returns
66      1 if successful in changing the parameter, else 0.
67 
68 * Vital statistics:
69 
70   Alignment:                            8-byte
71        8 byte alignment is currently hardwired into the design.  This
72        seems to suffice for all current machines and C compilers.
73 
74   Assumed pointer representation:       4 or 8 bytes
75        Code for 8-byte pointers is untested by me but has worked
76        reliably by Wolfram Gloger, who contributed most of the
77        changes supporting this.
78 
79   Assumed size_t  representation:       4 or 8 bytes
80        Note that size_t is allowed to be 4 bytes even if pointers are 8.
81 
82   Minimum overhead per allocated chunk: 4 or 8 bytes
83        Each malloced chunk has a hidden overhead of 4 bytes holding size
84        and status information.
85 
86   Minimum allocated size: 4-byte ptrs:  16 bytes    (including 4 overhead)
87 			  8-byte ptrs:  24/32 bytes (including, 4/8 overhead)
88 
89        When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
90        ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
91        needed; 4 (8) for a trailing size field
92        and 8 (16) bytes for free list pointers. Thus, the minimum
93        allocatable size is 16/24/32 bytes.
94 
95        Even a request for zero bytes (i.e., malloc(0)) returns a
96        pointer to something of the minimum allocatable size.
97 
98   Maximum allocated size: 4-byte size_t: 2^31 -  8 bytes
99 			  8-byte size_t: 2^63 - 16 bytes
100 
101        It is assumed that (possibly signed) size_t bit values suffice to
102        represent chunk sizes. `Possibly signed' is due to the fact
103        that `size_t' may be defined on a system as either a signed or
104        an unsigned type. To be conservative, values that would appear
105        as negative numbers are avoided.
106        Requests for sizes with a negative sign bit when the request
107        size is treaded as a long will return null.
108 
109   Maximum overhead wastage per allocated chunk: normally 15 bytes
110 
111        Alignnment demands, plus the minimum allocatable size restriction
112        make the normal worst-case wastage 15 bytes (i.e., up to 15
113        more bytes will be allocated than were requested in malloc), with
114        two exceptions:
115 	 1. Because requests for zero bytes allocate non-zero space,
116 	    the worst case wastage for a request of zero bytes is 24 bytes.
117 	 2. For requests >= mmap_threshold that are serviced via
118 	    mmap(), the worst case wastage is 8 bytes plus the remainder
119 	    from a system page (the minimal mmap unit); typically 4096 bytes.
120 
121 * Limitations
122 
123     Here are some features that are NOT currently supported
124 
125     * No user-definable hooks for callbacks and the like.
126     * No automated mechanism for fully checking that all accesses
127       to malloced memory stay within their bounds.
128     * No support for compaction.
129 
130 * Synopsis of compile-time options:
131 
132     People have reported using previous versions of this malloc on all
133     versions of Unix, sometimes by tweaking some of the defines
134     below. It has been tested most extensively on Solaris and
135     Linux. It is also reported to work on WIN32 platforms.
136     People have also reported adapting this malloc for use in
137     stand-alone embedded systems.
138 
139     The implementation is in straight, hand-tuned ANSI C.  Among other
140     consequences, it uses a lot of macros.  Because of this, to be at
141     all usable, this code should be compiled using an optimizing compiler
142     (for example gcc -O2) that can simplify expressions and control
143     paths.
144 
145   __STD_C                  (default: derived from C compiler defines)
146      Nonzero if using ANSI-standard C compiler, a C++ compiler, or
147      a C compiler sufficiently close to ANSI to get away with it.
148   DEBUG                    (default: NOT defined)
149      Define to enable debugging. Adds fairly extensive assertion-based
150      checking to help track down memory errors, but noticeably slows down
151      execution.
152   REALLOC_ZERO_BYTES_FREES (default: NOT defined)
153      Define this if you think that realloc(p, 0) should be equivalent
154      to free(p). Otherwise, since malloc returns a unique pointer for
155      malloc(0), so does realloc(p, 0).
156   HAVE_MEMCPY               (default: defined)
157      Define if you are not otherwise using ANSI STD C, but still
158      have memcpy and memset in your C library and want to use them.
159      Otherwise, simple internal versions are supplied.
160   USE_MEMCPY               (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
161      Define as 1 if you want the C library versions of memset and
162      memcpy called in realloc and calloc (otherwise macro versions are used).
163      At least on some platforms, the simple macro versions usually
164      outperform libc versions.
165   HAVE_MMAP                 (default: defined as 1)
166      Define to non-zero to optionally make malloc() use mmap() to
167      allocate very large blocks.
168   HAVE_MREMAP                 (default: defined as 0 unless Linux libc set)
169      Define to non-zero to optionally make realloc() use mremap() to
170      reallocate very large blocks.
171   malloc_getpagesize        (default: derived from system #includes)
172      Either a constant or routine call returning the system page size.
173   HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
174      Optionally define if you are on a system with a /usr/include/malloc.h
175      that declares struct mallinfo. It is not at all necessary to
176      define this even if you do, but will ensure consistency.
177   INTERNAL_SIZE_T           (default: size_t)
178      Define to a 32-bit type (probably `unsigned int') if you are on a
179      64-bit machine, yet do not want or need to allow malloc requests of
180      greater than 2^31 to be handled. This saves space, especially for
181      very small chunks.
182   INTERNAL_LINUX_C_LIB      (default: NOT defined)
183      Defined only when compiled as part of Linux libc.
184      Also note that there is some odd internal name-mangling via defines
185      (for example, internally, `malloc' is named `mALLOc') needed
186      when compiling in this case. These look funny but don't otherwise
187      affect anything.
188   WIN32                     (default: undefined)
189      Define this on MS win (95, nt) platforms to compile in sbrk emulation.
190   LACKS_UNISTD_H            (default: undefined if not WIN32)
191      Define this if your system does not have a <unistd.h>.
192   LACKS_SYS_PARAM_H         (default: undefined if not WIN32)
193      Define this if your system does not have a <sys/param.h>.
194   MORECORE                  (default: sbrk)
195      The name of the routine to call to obtain more memory from the system.
196   MORECORE_FAILURE          (default: -1)
197      The value returned upon failure of MORECORE.
198   MORECORE_CLEARS           (default 1)
199      True (1) if the routine mapped to MORECORE zeroes out memory (which
200      holds for sbrk).
201   DEFAULT_TRIM_THRESHOLD
202   DEFAULT_TOP_PAD
203   DEFAULT_MMAP_THRESHOLD
204   DEFAULT_MMAP_MAX
205      Default values of tunable parameters (described in detail below)
206      controlling interaction with host system routines (sbrk, mmap, etc).
207      These values may also be changed dynamically via mallopt(). The
208      preset defaults are those that give best performance for typical
209      programs/systems.
210   USE_DL_PREFIX             (default: undefined)
211      Prefix all public routines with the string 'dl'.  Useful to
212      quickly avoid procedure declaration conflicts and linker symbol
213      conflicts with existing memory allocation routines.
214 
215 
216 */
217 
218 
219 #ifndef __MALLOC_H__
220 #define __MALLOC_H__
221 
222 /* Preliminaries */
223 
224 #ifndef __STD_C
225 #ifdef __STDC__
226 #define __STD_C     1
227 #else
228 #if __cplusplus
229 #define __STD_C     1
230 #else
231 #define __STD_C     0
232 #endif /*__cplusplus*/
233 #endif /*__STDC__*/
234 #endif /*__STD_C*/
235 
236 #ifndef Void_t
237 #if (__STD_C || defined(WIN32))
238 #define Void_t      void
239 #else
240 #define Void_t      char
241 #endif
242 #endif /*Void_t*/
243 
244 #if __STD_C
245 #include <linux/stddef.h>	/* for size_t */
246 #else
247 #include <sys/types.h>
248 #endif	/* __STD_C */
249 
250 #ifdef __cplusplus
251 extern "C" {
252 #endif
253 
254 #if 0	/* not for U-Boot */
255 #include <stdio.h>	/* needed for malloc_stats */
256 #endif
257 
258 
259 /*
260   Compile-time options
261 */
262 
263 
264 /*
265     Debugging:
266 
267     Because freed chunks may be overwritten with link fields, this
268     malloc will often die when freed memory is overwritten by user
269     programs.  This can be very effective (albeit in an annoying way)
270     in helping track down dangling pointers.
271 
272     If you compile with -DDEBUG, a number of assertion checks are
273     enabled that will catch more memory errors. You probably won't be
274     able to make much sense of the actual assertion errors, but they
275     should help you locate incorrectly overwritten memory.  The
276     checking is fairly extensive, and will slow down execution
277     noticeably. Calling malloc_stats or mallinfo with DEBUG set will
278     attempt to check every non-mmapped allocated and free chunk in the
279     course of computing the summmaries. (By nature, mmapped regions
280     cannot be checked very much automatically.)
281 
282     Setting DEBUG may also be helpful if you are trying to modify
283     this code. The assertions in the check routines spell out in more
284     detail the assumptions and invariants underlying the algorithms.
285 
286 */
287 
288 #ifdef DEBUG
289 /* #include <assert.h> */
290 #define assert(x) ((void)0)
291 #else
292 #define assert(x) ((void)0)
293 #endif
294 
295 
296 /*
297   INTERNAL_SIZE_T is the word-size used for internal bookkeeping
298   of chunk sizes. On a 64-bit machine, you can reduce malloc
299   overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
300   at the expense of not being able to handle requests greater than
301   2^31. This limitation is hardly ever a concern; you are encouraged
302   to set this. However, the default version is the same as size_t.
303 */
304 
305 #ifndef INTERNAL_SIZE_T
306 #define INTERNAL_SIZE_T size_t
307 #endif
308 
309 /*
310   REALLOC_ZERO_BYTES_FREES should be set if a call to
311   realloc with zero bytes should be the same as a call to free.
312   Some people think it should. Otherwise, since this malloc
313   returns a unique pointer for malloc(0), so does realloc(p, 0).
314 */
315 
316 
317 /*   #define REALLOC_ZERO_BYTES_FREES */
318 
319 
320 /*
321   WIN32 causes an emulation of sbrk to be compiled in
322   mmap-based options are not currently supported in WIN32.
323 */
324 
325 /* #define WIN32 */
326 #ifdef WIN32
327 #define MORECORE wsbrk
328 #define HAVE_MMAP 0
329 
330 #define LACKS_UNISTD_H
331 #define LACKS_SYS_PARAM_H
332 
333 /*
334   Include 'windows.h' to get the necessary declarations for the
335   Microsoft Visual C++ data structures and routines used in the 'sbrk'
336   emulation.
337 
338   Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft
339   Visual C++ header files are included.
340 */
341 #define WIN32_LEAN_AND_MEAN
342 #include <windows.h>
343 #endif
344 
345 
346 /*
347   HAVE_MEMCPY should be defined if you are not otherwise using
348   ANSI STD C, but still have memcpy and memset in your C library
349   and want to use them in calloc and realloc. Otherwise simple
350   macro versions are defined here.
351 
352   USE_MEMCPY should be defined as 1 if you actually want to
353   have memset and memcpy called. People report that the macro
354   versions are often enough faster than libc versions on many
355   systems that it is better to use them.
356 
357 */
358 
359 #define HAVE_MEMCPY
360 
361 #ifndef USE_MEMCPY
362 #ifdef HAVE_MEMCPY
363 #define USE_MEMCPY 1
364 #else
365 #define USE_MEMCPY 0
366 #endif
367 #endif
368 
369 #if (__STD_C || defined(HAVE_MEMCPY))
370 
371 #if __STD_C
372 void* memset(void*, int, size_t);
373 void* memcpy(void*, const void*, size_t);
374 #else
375 #ifdef WIN32
376 /* On Win32 platforms, 'memset()' and 'memcpy()' are already declared in */
377 /* 'windows.h' */
378 #else
379 Void_t* memset();
380 Void_t* memcpy();
381 #endif
382 #endif
383 #endif
384 
385 #if USE_MEMCPY
386 
387 /* The following macros are only invoked with (2n+1)-multiples of
388    INTERNAL_SIZE_T units, with a positive integer n. This is exploited
389    for fast inline execution when n is small. */
390 
391 #define MALLOC_ZERO(charp, nbytes)                                            \
392 do {                                                                          \
393   INTERNAL_SIZE_T mzsz = (nbytes);                                            \
394   if(mzsz <= 9*sizeof(mzsz)) {                                                \
395     INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp);                         \
396     if(mzsz >= 5*sizeof(mzsz)) {     *mz++ = 0;                               \
397 				     *mz++ = 0;                               \
398       if(mzsz >= 7*sizeof(mzsz)) {   *mz++ = 0;                               \
399 				     *mz++ = 0;                               \
400 	if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0;                               \
401 				     *mz++ = 0; }}}                           \
402 				     *mz++ = 0;                               \
403 				     *mz++ = 0;                               \
404 				     *mz   = 0;                               \
405   } else memset((charp), 0, mzsz);                                            \
406 } while(0)
407 
408 #define MALLOC_COPY(dest,src,nbytes)                                          \
409 do {                                                                          \
410   INTERNAL_SIZE_T mcsz = (nbytes);                                            \
411   if(mcsz <= 9*sizeof(mcsz)) {                                                \
412     INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src);                        \
413     INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest);                       \
414     if(mcsz >= 5*sizeof(mcsz)) {     *mcdst++ = *mcsrc++;                     \
415 				     *mcdst++ = *mcsrc++;                     \
416       if(mcsz >= 7*sizeof(mcsz)) {   *mcdst++ = *mcsrc++;                     \
417 				     *mcdst++ = *mcsrc++;                     \
418 	if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++;                     \
419 				     *mcdst++ = *mcsrc++; }}}                 \
420 				     *mcdst++ = *mcsrc++;                     \
421 				     *mcdst++ = *mcsrc++;                     \
422 				     *mcdst   = *mcsrc  ;                     \
423   } else memcpy(dest, src, mcsz);                                             \
424 } while(0)
425 
426 #else /* !USE_MEMCPY */
427 
428 /* Use Duff's device for good zeroing/copying performance. */
429 
430 #define MALLOC_ZERO(charp, nbytes)                                            \
431 do {                                                                          \
432   INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp);                           \
433   long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
434   if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
435   switch (mctmp) {                                                            \
436     case 0: for(;;) { *mzp++ = 0;                                             \
437     case 7:           *mzp++ = 0;                                             \
438     case 6:           *mzp++ = 0;                                             \
439     case 5:           *mzp++ = 0;                                             \
440     case 4:           *mzp++ = 0;                                             \
441     case 3:           *mzp++ = 0;                                             \
442     case 2:           *mzp++ = 0;                                             \
443     case 1:           *mzp++ = 0; if(mcn <= 0) break; mcn--; }                \
444   }                                                                           \
445 } while(0)
446 
447 #define MALLOC_COPY(dest,src,nbytes)                                          \
448 do {                                                                          \
449   INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src;                            \
450   INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest;                           \
451   long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn;                         \
452   if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; }             \
453   switch (mctmp) {                                                            \
454     case 0: for(;;) { *mcdst++ = *mcsrc++;                                    \
455     case 7:           *mcdst++ = *mcsrc++;                                    \
456     case 6:           *mcdst++ = *mcsrc++;                                    \
457     case 5:           *mcdst++ = *mcsrc++;                                    \
458     case 4:           *mcdst++ = *mcsrc++;                                    \
459     case 3:           *mcdst++ = *mcsrc++;                                    \
460     case 2:           *mcdst++ = *mcsrc++;                                    \
461     case 1:           *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; }       \
462   }                                                                           \
463 } while(0)
464 
465 #endif
466 
467 
468 /*
469   Define HAVE_MMAP to optionally make malloc() use mmap() to
470   allocate very large blocks.  These will be returned to the
471   operating system immediately after a free().
472 */
473 
474 /***
475 #ifndef HAVE_MMAP
476 #define HAVE_MMAP 1
477 #endif
478 ***/
479 #undef	HAVE_MMAP	/* Not available for U-Boot */
480 
481 /*
482   Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
483   large blocks.  This is currently only possible on Linux with
484   kernel versions newer than 1.3.77.
485 */
486 
487 /***
488 #ifndef HAVE_MREMAP
489 #ifdef INTERNAL_LINUX_C_LIB
490 #define HAVE_MREMAP 1
491 #else
492 #define HAVE_MREMAP 0
493 #endif
494 #endif
495 ***/
496 #undef	HAVE_MREMAP	/* Not available for U-Boot */
497 
498 #if HAVE_MMAP
499 
500 #include <unistd.h>
501 #include <fcntl.h>
502 #include <sys/mman.h>
503 
504 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
505 #define MAP_ANONYMOUS MAP_ANON
506 #endif
507 
508 #endif /* HAVE_MMAP */
509 
510 /*
511   Access to system page size. To the extent possible, this malloc
512   manages memory from the system in page-size units.
513 
514   The following mechanics for getpagesize were adapted from
515   bsd/gnu getpagesize.h
516 */
517 
518 #define	LACKS_UNISTD_H	/* Shortcut for U-Boot */
519 #define	malloc_getpagesize	4096
520 
521 #ifndef LACKS_UNISTD_H
522 #  include <unistd.h>
523 #endif
524 
525 #ifndef malloc_getpagesize
526 #  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
527 #    ifndef _SC_PAGE_SIZE
528 #      define _SC_PAGE_SIZE _SC_PAGESIZE
529 #    endif
530 #  endif
531 #  ifdef _SC_PAGE_SIZE
532 #    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
533 #  else
534 #    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
535        extern size_t getpagesize();
536 #      define malloc_getpagesize getpagesize()
537 #    else
538 #      ifdef WIN32
539 #        define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */
540 #      else
541 #        ifndef LACKS_SYS_PARAM_H
542 #          include <sys/param.h>
543 #        endif
544 #        ifdef EXEC_PAGESIZE
545 #          define malloc_getpagesize EXEC_PAGESIZE
546 #        else
547 #          ifdef NBPG
548 #            ifndef CLSIZE
549 #              define malloc_getpagesize NBPG
550 #            else
551 #              define malloc_getpagesize (NBPG * CLSIZE)
552 #            endif
553 #          else
554 #            ifdef NBPC
555 #              define malloc_getpagesize NBPC
556 #            else
557 #              ifdef PAGESIZE
558 #                define malloc_getpagesize PAGESIZE
559 #              else
560 #                define malloc_getpagesize (4096) /* just guess */
561 #              endif
562 #            endif
563 #          endif
564 #        endif
565 #      endif
566 #    endif
567 #  endif
568 #endif
569 
570 
571 /*
572 
573   This version of malloc supports the standard SVID/XPG mallinfo
574   routine that returns a struct containing the same kind of
575   information you can get from malloc_stats. It should work on
576   any SVID/XPG compliant system that has a /usr/include/malloc.h
577   defining struct mallinfo. (If you'd like to install such a thing
578   yourself, cut out the preliminary declarations as described above
579   and below and save them in a malloc.h file. But there's no
580   compelling reason to bother to do this.)
581 
582   The main declaration needed is the mallinfo struct that is returned
583   (by-copy) by mallinfo().  The SVID/XPG malloinfo struct contains a
584   bunch of fields, most of which are not even meaningful in this
585   version of malloc. Some of these fields are are instead filled by
586   mallinfo() with other numbers that might possibly be of interest.
587 
588   HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
589   /usr/include/malloc.h file that includes a declaration of struct
590   mallinfo.  If so, it is included; else an SVID2/XPG2 compliant
591   version is declared below.  These must be precisely the same for
592   mallinfo() to work.
593 
594 */
595 
596 /* #define HAVE_USR_INCLUDE_MALLOC_H */
597 
598 #if HAVE_USR_INCLUDE_MALLOC_H
599 #include "/usr/include/malloc.h"
600 #else
601 
602 /* SVID2/XPG mallinfo structure */
603 
604 struct mallinfo {
605   int arena;    /* total space allocated from system */
606   int ordblks;  /* number of non-inuse chunks */
607   int smblks;   /* unused -- always zero */
608   int hblks;    /* number of mmapped regions */
609   int hblkhd;   /* total space in mmapped regions */
610   int usmblks;  /* unused -- always zero */
611   int fsmblks;  /* unused -- always zero */
612   int uordblks; /* total allocated space */
613   int fordblks; /* total non-inuse space */
614   int keepcost; /* top-most, releasable (via malloc_trim) space */
615 };
616 
617 /* SVID2/XPG mallopt options */
618 
619 #define M_MXFAST  1    /* UNUSED in this malloc */
620 #define M_NLBLKS  2    /* UNUSED in this malloc */
621 #define M_GRAIN   3    /* UNUSED in this malloc */
622 #define M_KEEP    4    /* UNUSED in this malloc */
623 
624 #endif
625 
626 /* mallopt options that actually do something */
627 
628 #define M_TRIM_THRESHOLD    -1
629 #define M_TOP_PAD           -2
630 #define M_MMAP_THRESHOLD    -3
631 #define M_MMAP_MAX          -4
632 
633 
634 #ifndef DEFAULT_TRIM_THRESHOLD
635 #define DEFAULT_TRIM_THRESHOLD (128 * 1024)
636 #endif
637 
638 /*
639     M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
640       to keep before releasing via malloc_trim in free().
641 
642       Automatic trimming is mainly useful in long-lived programs.
643       Because trimming via sbrk can be slow on some systems, and can
644       sometimes be wasteful (in cases where programs immediately
645       afterward allocate more large chunks) the value should be high
646       enough so that your overall system performance would improve by
647       releasing.
648 
649       The trim threshold and the mmap control parameters (see below)
650       can be traded off with one another. Trimming and mmapping are
651       two different ways of releasing unused memory back to the
652       system. Between these two, it is often possible to keep
653       system-level demands of a long-lived program down to a bare
654       minimum. For example, in one test suite of sessions measuring
655       the XF86 X server on Linux, using a trim threshold of 128K and a
656       mmap threshold of 192K led to near-minimal long term resource
657       consumption.
658 
659       If you are using this malloc in a long-lived program, it should
660       pay to experiment with these values.  As a rough guide, you
661       might set to a value close to the average size of a process
662       (program) running on your system.  Releasing this much memory
663       would allow such a process to run in memory.  Generally, it's
664       worth it to tune for trimming rather tham memory mapping when a
665       program undergoes phases where several large chunks are
666       allocated and released in ways that can reuse each other's
667       storage, perhaps mixed with phases where there are no such
668       chunks at all.  And in well-behaved long-lived programs,
669       controlling release of large blocks via trimming versus mapping
670       is usually faster.
671 
672       However, in most programs, these parameters serve mainly as
673       protection against the system-level effects of carrying around
674       massive amounts of unneeded memory. Since frequent calls to
675       sbrk, mmap, and munmap otherwise degrade performance, the default
676       parameters are set to relatively high values that serve only as
677       safeguards.
678 
679       The default trim value is high enough to cause trimming only in
680       fairly extreme (by current memory consumption standards) cases.
681       It must be greater than page size to have any useful effect.  To
682       disable trimming completely, you can set to (unsigned long)(-1);
683 
684 
685 */
686 
687 
688 #ifndef DEFAULT_TOP_PAD
689 #define DEFAULT_TOP_PAD        (0)
690 #endif
691 
692 /*
693     M_TOP_PAD is the amount of extra `padding' space to allocate or
694       retain whenever sbrk is called. It is used in two ways internally:
695 
696       * When sbrk is called to extend the top of the arena to satisfy
697 	a new malloc request, this much padding is added to the sbrk
698 	request.
699 
700       * When malloc_trim is called automatically from free(),
701 	it is used as the `pad' argument.
702 
703       In both cases, the actual amount of padding is rounded
704       so that the end of the arena is always a system page boundary.
705 
706       The main reason for using padding is to avoid calling sbrk so
707       often. Having even a small pad greatly reduces the likelihood
708       that nearly every malloc request during program start-up (or
709       after trimming) will invoke sbrk, which needlessly wastes
710       time.
711 
712       Automatic rounding-up to page-size units is normally sufficient
713       to avoid measurable overhead, so the default is 0.  However, in
714       systems where sbrk is relatively slow, it can pay to increase
715       this value, at the expense of carrying around more memory than
716       the program needs.
717 
718 */
719 
720 
721 #ifndef DEFAULT_MMAP_THRESHOLD
722 #define DEFAULT_MMAP_THRESHOLD (128 * 1024)
723 #endif
724 
725 /*
726 
727     M_MMAP_THRESHOLD is the request size threshold for using mmap()
728       to service a request. Requests of at least this size that cannot
729       be allocated using already-existing space will be serviced via mmap.
730       (If enough normal freed space already exists it is used instead.)
731 
732       Using mmap segregates relatively large chunks of memory so that
733       they can be individually obtained and released from the host
734       system. A request serviced through mmap is never reused by any
735       other request (at least not directly; the system may just so
736       happen to remap successive requests to the same locations).
737 
738       Segregating space in this way has the benefit that mmapped space
739       can ALWAYS be individually released back to the system, which
740       helps keep the system level memory demands of a long-lived
741       program low. Mapped memory can never become `locked' between
742       other chunks, as can happen with normally allocated chunks, which
743       menas that even trimming via malloc_trim would not release them.
744 
745       However, it has the disadvantages that:
746 
747 	 1. The space cannot be reclaimed, consolidated, and then
748 	    used to service later requests, as happens with normal chunks.
749 	 2. It can lead to more wastage because of mmap page alignment
750 	    requirements
751 	 3. It causes malloc performance to be more dependent on host
752 	    system memory management support routines which may vary in
753 	    implementation quality and may impose arbitrary
754 	    limitations. Generally, servicing a request via normal
755 	    malloc steps is faster than going through a system's mmap.
756 
757       All together, these considerations should lead you to use mmap
758       only for relatively large requests.
759 
760 
761 */
762 
763 
764 #ifndef DEFAULT_MMAP_MAX
765 #if HAVE_MMAP
766 #define DEFAULT_MMAP_MAX       (64)
767 #else
768 #define DEFAULT_MMAP_MAX       (0)
769 #endif
770 #endif
771 
772 /*
773     M_MMAP_MAX is the maximum number of requests to simultaneously
774       service using mmap. This parameter exists because:
775 
776 	 1. Some systems have a limited number of internal tables for
777 	    use by mmap.
778 	 2. In most systems, overreliance on mmap can degrade overall
779 	    performance.
780 	 3. If a program allocates many large regions, it is probably
781 	    better off using normal sbrk-based allocation routines that
782 	    can reclaim and reallocate normal heap memory. Using a
783 	    small value allows transition into this mode after the
784 	    first few allocations.
785 
786       Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
787       the default value is 0, and attempts to set it to non-zero values
788       in mallopt will fail.
789 */
790 
791 
792 /*
793     USE_DL_PREFIX will prefix all public routines with the string 'dl'.
794       Useful to quickly avoid procedure declaration conflicts and linker
795       symbol conflicts with existing memory allocation routines.
796 
797 */
798 
799 /* #define USE_DL_PREFIX */
800 
801 
802 /*
803 
804   Special defines for linux libc
805 
806   Except when compiled using these special defines for Linux libc
807   using weak aliases, this malloc is NOT designed to work in
808   multithreaded applications.  No semaphores or other concurrency
809   control are provided to ensure that multiple malloc or free calls
810   don't run at the same time, which could be disasterous. A single
811   semaphore could be used across malloc, realloc, and free (which is
812   essentially the effect of the linux weak alias approach). It would
813   be hard to obtain finer granularity.
814 
815 */
816 
817 
818 #ifdef INTERNAL_LINUX_C_LIB
819 
820 #if __STD_C
821 
822 Void_t * __default_morecore_init (ptrdiff_t);
823 Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
824 
825 #else
826 
827 Void_t * __default_morecore_init ();
828 Void_t *(*__morecore)() = __default_morecore_init;
829 
830 #endif
831 
832 #define MORECORE (*__morecore)
833 #define MORECORE_FAILURE 0
834 #define MORECORE_CLEARS 1
835 
836 #else /* INTERNAL_LINUX_C_LIB */
837 
838 #if __STD_C
839 extern Void_t*     sbrk(ptrdiff_t);
840 #else
841 extern Void_t*     sbrk();
842 #endif
843 
844 #ifndef MORECORE
845 #define MORECORE sbrk
846 #endif
847 
848 #ifndef MORECORE_FAILURE
849 #define MORECORE_FAILURE -1
850 #endif
851 
852 #ifndef MORECORE_CLEARS
853 #define MORECORE_CLEARS 1
854 #endif
855 
856 #endif /* INTERNAL_LINUX_C_LIB */
857 
858 #if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)
859 
860 #define cALLOc		__libc_calloc
861 #define fREe		__libc_free
862 #define mALLOc		__libc_malloc
863 #define mEMALIGn	__libc_memalign
864 #define rEALLOc		__libc_realloc
865 #define vALLOc		__libc_valloc
866 #define pvALLOc		__libc_pvalloc
867 #define mALLINFo	__libc_mallinfo
868 #define mALLOPt		__libc_mallopt
869 
870 #pragma weak calloc = __libc_calloc
871 #pragma weak free = __libc_free
872 #pragma weak cfree = __libc_free
873 #pragma weak malloc = __libc_malloc
874 #pragma weak memalign = __libc_memalign
875 #pragma weak realloc = __libc_realloc
876 #pragma weak valloc = __libc_valloc
877 #pragma weak pvalloc = __libc_pvalloc
878 #pragma weak mallinfo = __libc_mallinfo
879 #pragma weak mallopt = __libc_mallopt
880 
881 #else
882 
883 #ifdef USE_DL_PREFIX
884 #define cALLOc		dlcalloc
885 #define fREe		dlfree
886 #define mALLOc		dlmalloc
887 #define mEMALIGn	dlmemalign
888 #define rEALLOc		dlrealloc
889 #define vALLOc		dlvalloc
890 #define pvALLOc		dlpvalloc
891 #define mALLINFo	dlmallinfo
892 #define mALLOPt		dlmallopt
893 #else /* USE_DL_PREFIX */
894 #define cALLOc		calloc
895 #define fREe		free
896 #define mALLOc		malloc
897 #define mEMALIGn	memalign
898 #define rEALLOc		realloc
899 #define vALLOc		valloc
900 #define pvALLOc		pvalloc
901 #define mALLINFo	mallinfo
902 #define mALLOPt		mallopt
903 #endif /* USE_DL_PREFIX */
904 
905 #endif
906 
907 /* Public routines */
908 
909 #if __STD_C
910 
911 Void_t* mALLOc(size_t);
912 void    fREe(Void_t*);
913 Void_t* rEALLOc(Void_t*, size_t);
914 Void_t* mEMALIGn(size_t, size_t);
915 Void_t* vALLOc(size_t);
916 Void_t* pvALLOc(size_t);
917 Void_t* cALLOc(size_t, size_t);
918 void    cfree(Void_t*);
919 int     malloc_trim(size_t);
920 size_t  malloc_usable_size(Void_t*);
921 void    malloc_stats(void);
922 int     mALLOPt(int, int);
923 struct mallinfo mALLINFo(void);
924 #else
925 Void_t* mALLOc();
926 void    fREe();
927 Void_t* rEALLOc();
928 Void_t* mEMALIGn();
929 Void_t* vALLOc();
930 Void_t* pvALLOc();
931 Void_t* cALLOc();
932 void    cfree();
933 int     malloc_trim();
934 size_t  malloc_usable_size();
935 void    malloc_stats();
936 int     mALLOPt();
937 struct mallinfo mALLINFo();
938 #endif
939 
940 /*
941  * Begin and End of memory area for malloc(), and current "brk"
942  */
943 extern ulong mem_malloc_start;
944 extern ulong mem_malloc_end;
945 extern ulong mem_malloc_brk;
946 
947 void mem_malloc_init(ulong start, ulong size);
948 
949 #ifdef __cplusplus
950 };  /* end of extern "C" */
951 #endif
952 
953 #endif /* __MALLOC_H__ */
954