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Kumar Gala81673e92008-05-13 19:01:54 -05001#include <common.h>
2
wdenk217c9da2002-10-25 20:35:49 +00003#if 0 /* Moved to malloc.h */
4/* ---------- To make a malloc.h, start cutting here ------------ */
5
6/*
7 A version of malloc/free/realloc written by Doug Lea and released to the
8 public domain. Send questions/comments/complaints/performance data
9 to dl@cs.oswego.edu
10
11* VERSION 2.6.6 Sun Mar 5 19:10:03 2000 Doug Lea (dl at gee)
12
13 Note: There may be an updated version of this malloc obtainable at
wdenk8bde7f72003-06-27 21:31:46 +000014 ftp://g.oswego.edu/pub/misc/malloc.c
15 Check before installing!
wdenk217c9da2002-10-25 20:35:49 +000016
17* Why use this malloc?
18
19 This is not the fastest, most space-conserving, most portable, or
20 most tunable malloc ever written. However it is among the fastest
21 while also being among the most space-conserving, portable and tunable.
22 Consistent balance across these factors results in a good general-purpose
23 allocator. For a high-level description, see
24 http://g.oswego.edu/dl/html/malloc.html
25
26* Synopsis of public routines
27
28 (Much fuller descriptions are contained in the program documentation below.)
29
30 malloc(size_t n);
31 Return a pointer to a newly allocated chunk of at least n bytes, or null
32 if no space is available.
33 free(Void_t* p);
34 Release the chunk of memory pointed to by p, or no effect if p is null.
35 realloc(Void_t* p, size_t n);
36 Return a pointer to a chunk of size n that contains the same data
37 as does chunk p up to the minimum of (n, p's size) bytes, or null
38 if no space is available. The returned pointer may or may not be
39 the same as p. If p is null, equivalent to malloc. Unless the
40 #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
41 size argument of zero (re)allocates a minimum-sized chunk.
42 memalign(size_t alignment, size_t n);
43 Return a pointer to a newly allocated chunk of n bytes, aligned
44 in accord with the alignment argument, which must be a power of
45 two.
46 valloc(size_t n);
47 Equivalent to memalign(pagesize, n), where pagesize is the page
48 size of the system (or as near to this as can be figured out from
49 all the includes/defines below.)
50 pvalloc(size_t n);
51 Equivalent to valloc(minimum-page-that-holds(n)), that is,
52 round up n to nearest pagesize.
53 calloc(size_t unit, size_t quantity);
54 Returns a pointer to quantity * unit bytes, with all locations
55 set to zero.
56 cfree(Void_t* p);
57 Equivalent to free(p).
58 malloc_trim(size_t pad);
59 Release all but pad bytes of freed top-most memory back
60 to the system. Return 1 if successful, else 0.
61 malloc_usable_size(Void_t* p);
62 Report the number usable allocated bytes associated with allocated
63 chunk p. This may or may not report more bytes than were requested,
64 due to alignment and minimum size constraints.
65 malloc_stats();
66 Prints brief summary statistics.
67 mallinfo()
68 Returns (by copy) a struct containing various summary statistics.
69 mallopt(int parameter_number, int parameter_value)
70 Changes one of the tunable parameters described below. Returns
71 1 if successful in changing the parameter, else 0.
72
73* Vital statistics:
74
75 Alignment: 8-byte
76 8 byte alignment is currently hardwired into the design. This
77 seems to suffice for all current machines and C compilers.
78
79 Assumed pointer representation: 4 or 8 bytes
80 Code for 8-byte pointers is untested by me but has worked
81 reliably by Wolfram Gloger, who contributed most of the
82 changes supporting this.
83
84 Assumed size_t representation: 4 or 8 bytes
85 Note that size_t is allowed to be 4 bytes even if pointers are 8.
86
87 Minimum overhead per allocated chunk: 4 or 8 bytes
88 Each malloced chunk has a hidden overhead of 4 bytes holding size
89 and status information.
90
91 Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
wdenk8bde7f72003-06-27 21:31:46 +000092 8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
wdenk217c9da2002-10-25 20:35:49 +000093
94 When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
95 ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
96 needed; 4 (8) for a trailing size field
97 and 8 (16) bytes for free list pointers. Thus, the minimum
98 allocatable size is 16/24/32 bytes.
99
100 Even a request for zero bytes (i.e., malloc(0)) returns a
101 pointer to something of the minimum allocatable size.
102
103 Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes
wdenk8bde7f72003-06-27 21:31:46 +0000104 8-byte size_t: 2^63 - 16 bytes
wdenk217c9da2002-10-25 20:35:49 +0000105
106 It is assumed that (possibly signed) size_t bit values suffice to
107 represent chunk sizes. `Possibly signed' is due to the fact
108 that `size_t' may be defined on a system as either a signed or
109 an unsigned type. To be conservative, values that would appear
110 as negative numbers are avoided.
111 Requests for sizes with a negative sign bit when the request
112 size is treaded as a long will return null.
113
114 Maximum overhead wastage per allocated chunk: normally 15 bytes
115
116 Alignnment demands, plus the minimum allocatable size restriction
117 make the normal worst-case wastage 15 bytes (i.e., up to 15
118 more bytes will be allocated than were requested in malloc), with
119 two exceptions:
wdenk8bde7f72003-06-27 21:31:46 +0000120 1. Because requests for zero bytes allocate non-zero space,
121 the worst case wastage for a request of zero bytes is 24 bytes.
122 2. For requests >= mmap_threshold that are serviced via
123 mmap(), the worst case wastage is 8 bytes plus the remainder
124 from a system page (the minimal mmap unit); typically 4096 bytes.
wdenk217c9da2002-10-25 20:35:49 +0000125
126* Limitations
127
128 Here are some features that are NOT currently supported
129
130 * No user-definable hooks for callbacks and the like.
131 * No automated mechanism for fully checking that all accesses
132 to malloced memory stay within their bounds.
133 * No support for compaction.
134
135* Synopsis of compile-time options:
136
137 People have reported using previous versions of this malloc on all
138 versions of Unix, sometimes by tweaking some of the defines
139 below. It has been tested most extensively on Solaris and
140 Linux. It is also reported to work on WIN32 platforms.
141 People have also reported adapting this malloc for use in
142 stand-alone embedded systems.
143
144 The implementation is in straight, hand-tuned ANSI C. Among other
145 consequences, it uses a lot of macros. Because of this, to be at
146 all usable, this code should be compiled using an optimizing compiler
147 (for example gcc -O2) that can simplify expressions and control
148 paths.
149
150 __STD_C (default: derived from C compiler defines)
151 Nonzero if using ANSI-standard C compiler, a C++ compiler, or
152 a C compiler sufficiently close to ANSI to get away with it.
153 DEBUG (default: NOT defined)
154 Define to enable debugging. Adds fairly extensive assertion-based
155 checking to help track down memory errors, but noticeably slows down
156 execution.
157 REALLOC_ZERO_BYTES_FREES (default: NOT defined)
158 Define this if you think that realloc(p, 0) should be equivalent
159 to free(p). Otherwise, since malloc returns a unique pointer for
160 malloc(0), so does realloc(p, 0).
161 HAVE_MEMCPY (default: defined)
162 Define if you are not otherwise using ANSI STD C, but still
163 have memcpy and memset in your C library and want to use them.
164 Otherwise, simple internal versions are supplied.
165 USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
166 Define as 1 if you want the C library versions of memset and
167 memcpy called in realloc and calloc (otherwise macro versions are used).
168 At least on some platforms, the simple macro versions usually
169 outperform libc versions.
170 HAVE_MMAP (default: defined as 1)
171 Define to non-zero to optionally make malloc() use mmap() to
172 allocate very large blocks.
173 HAVE_MREMAP (default: defined as 0 unless Linux libc set)
174 Define to non-zero to optionally make realloc() use mremap() to
175 reallocate very large blocks.
176 malloc_getpagesize (default: derived from system #includes)
177 Either a constant or routine call returning the system page size.
178 HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
179 Optionally define if you are on a system with a /usr/include/malloc.h
180 that declares struct mallinfo. It is not at all necessary to
181 define this even if you do, but will ensure consistency.
182 INTERNAL_SIZE_T (default: size_t)
183 Define to a 32-bit type (probably `unsigned int') if you are on a
184 64-bit machine, yet do not want or need to allow malloc requests of
185 greater than 2^31 to be handled. This saves space, especially for
186 very small chunks.
187 INTERNAL_LINUX_C_LIB (default: NOT defined)
188 Defined only when compiled as part of Linux libc.
189 Also note that there is some odd internal name-mangling via defines
190 (for example, internally, `malloc' is named `mALLOc') needed
191 when compiling in this case. These look funny but don't otherwise
192 affect anything.
193 WIN32 (default: undefined)
194 Define this on MS win (95, nt) platforms to compile in sbrk emulation.
195 LACKS_UNISTD_H (default: undefined if not WIN32)
196 Define this if your system does not have a <unistd.h>.
197 LACKS_SYS_PARAM_H (default: undefined if not WIN32)
198 Define this if your system does not have a <sys/param.h>.
199 MORECORE (default: sbrk)
200 The name of the routine to call to obtain more memory from the system.
201 MORECORE_FAILURE (default: -1)
202 The value returned upon failure of MORECORE.
203 MORECORE_CLEARS (default 1)
204 True (1) if the routine mapped to MORECORE zeroes out memory (which
205 holds for sbrk).
206 DEFAULT_TRIM_THRESHOLD
207 DEFAULT_TOP_PAD
208 DEFAULT_MMAP_THRESHOLD
209 DEFAULT_MMAP_MAX
210 Default values of tunable parameters (described in detail below)
211 controlling interaction with host system routines (sbrk, mmap, etc).
212 These values may also be changed dynamically via mallopt(). The
213 preset defaults are those that give best performance for typical
214 programs/systems.
215 USE_DL_PREFIX (default: undefined)
216 Prefix all public routines with the string 'dl'. Useful to
217 quickly avoid procedure declaration conflicts and linker symbol
218 conflicts with existing memory allocation routines.
219
220
221*/
222
223
224
225
226/* Preliminaries */
227
228#ifndef __STD_C
229#ifdef __STDC__
230#define __STD_C 1
231#else
232#if __cplusplus
233#define __STD_C 1
234#else
235#define __STD_C 0
236#endif /*__cplusplus*/
237#endif /*__STDC__*/
238#endif /*__STD_C*/
239
240#ifndef Void_t
241#if (__STD_C || defined(WIN32))
242#define Void_t void
243#else
244#define Void_t char
245#endif
246#endif /*Void_t*/
247
248#if __STD_C
249#include <stddef.h> /* for size_t */
250#else
251#include <sys/types.h>
252#endif
253
254#ifdef __cplusplus
255extern "C" {
256#endif
257
258#include <stdio.h> /* needed for malloc_stats */
259
260
261/*
262 Compile-time options
263*/
264
265
266/*
267 Debugging:
268
269 Because freed chunks may be overwritten with link fields, this
270 malloc will often die when freed memory is overwritten by user
271 programs. This can be very effective (albeit in an annoying way)
272 in helping track down dangling pointers.
273
274 If you compile with -DDEBUG, a number of assertion checks are
275 enabled that will catch more memory errors. You probably won't be
276 able to make much sense of the actual assertion errors, but they
277 should help you locate incorrectly overwritten memory. The
278 checking is fairly extensive, and will slow down execution
279 noticeably. Calling malloc_stats or mallinfo with DEBUG set will
280 attempt to check every non-mmapped allocated and free chunk in the
281 course of computing the summmaries. (By nature, mmapped regions
282 cannot be checked very much automatically.)
283
284 Setting DEBUG may also be helpful if you are trying to modify
285 this code. The assertions in the check routines spell out in more
286 detail the assumptions and invariants underlying the algorithms.
287
288*/
289
290#ifdef DEBUG
291#include <assert.h>
292#else
293#define assert(x) ((void)0)
294#endif
295
296
297/*
298 INTERNAL_SIZE_T is the word-size used for internal bookkeeping
299 of chunk sizes. On a 64-bit machine, you can reduce malloc
300 overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int'
301 at the expense of not being able to handle requests greater than
302 2^31. This limitation is hardly ever a concern; you are encouraged
303 to set this. However, the default version is the same as size_t.
304*/
305
306#ifndef INTERNAL_SIZE_T
307#define INTERNAL_SIZE_T size_t
308#endif
309
310/*
311 REALLOC_ZERO_BYTES_FREES should be set if a call to
312 realloc with zero bytes should be the same as a call to free.
313 Some people think it should. Otherwise, since this malloc
314 returns a unique pointer for malloc(0), so does realloc(p, 0).
315*/
316
317
318/* #define REALLOC_ZERO_BYTES_FREES */
319
320
321/*
322 WIN32 causes an emulation of sbrk to be compiled in
323 mmap-based options are not currently supported in WIN32.
324*/
325
326/* #define WIN32 */
327#ifdef WIN32
328#define MORECORE wsbrk
329#define HAVE_MMAP 0
330
331#define LACKS_UNISTD_H
332#define LACKS_SYS_PARAM_H
333
334/*
335 Include 'windows.h' to get the necessary declarations for the
336 Microsoft Visual C++ data structures and routines used in the 'sbrk'
337 emulation.
338
339 Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft
340 Visual C++ header files are included.
341*/
342#define WIN32_LEAN_AND_MEAN
343#include <windows.h>
344#endif
345
346
347/*
348 HAVE_MEMCPY should be defined if you are not otherwise using
349 ANSI STD C, but still have memcpy and memset in your C library
350 and want to use them in calloc and realloc. Otherwise simple
351 macro versions are defined here.
352
353 USE_MEMCPY should be defined as 1 if you actually want to
354 have memset and memcpy called. People report that the macro
355 versions are often enough faster than libc versions on many
356 systems that it is better to use them.
357
358*/
359
360#define HAVE_MEMCPY
361
362#ifndef USE_MEMCPY
363#ifdef HAVE_MEMCPY
364#define USE_MEMCPY 1
365#else
366#define USE_MEMCPY 0
367#endif
368#endif
369
370#if (__STD_C || defined(HAVE_MEMCPY))
371
372#if __STD_C
373void* memset(void*, int, size_t);
374void* memcpy(void*, const void*, size_t);
375#else
376#ifdef WIN32
wdenk8bde7f72003-06-27 21:31:46 +0000377/* On Win32 platforms, 'memset()' and 'memcpy()' are already declared in */
378/* 'windows.h' */
wdenk217c9da2002-10-25 20:35:49 +0000379#else
380Void_t* memset();
381Void_t* memcpy();
382#endif
383#endif
384#endif
385
386#if USE_MEMCPY
387
388/* The following macros are only invoked with (2n+1)-multiples of
389 INTERNAL_SIZE_T units, with a positive integer n. This is exploited
390 for fast inline execution when n is small. */
391
392#define MALLOC_ZERO(charp, nbytes) \
393do { \
394 INTERNAL_SIZE_T mzsz = (nbytes); \
395 if(mzsz <= 9*sizeof(mzsz)) { \
396 INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp); \
397 if(mzsz >= 5*sizeof(mzsz)) { *mz++ = 0; \
wdenk8bde7f72003-06-27 21:31:46 +0000398 *mz++ = 0; \
wdenk217c9da2002-10-25 20:35:49 +0000399 if(mzsz >= 7*sizeof(mzsz)) { *mz++ = 0; \
wdenk8bde7f72003-06-27 21:31:46 +0000400 *mz++ = 0; \
401 if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0; \
402 *mz++ = 0; }}} \
403 *mz++ = 0; \
404 *mz++ = 0; \
405 *mz = 0; \
wdenk217c9da2002-10-25 20:35:49 +0000406 } else memset((charp), 0, mzsz); \
407} while(0)
408
409#define MALLOC_COPY(dest,src,nbytes) \
410do { \
411 INTERNAL_SIZE_T mcsz = (nbytes); \
412 if(mcsz <= 9*sizeof(mcsz)) { \
413 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src); \
414 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest); \
415 if(mcsz >= 5*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \
wdenk8bde7f72003-06-27 21:31:46 +0000416 *mcdst++ = *mcsrc++; \
wdenk217c9da2002-10-25 20:35:49 +0000417 if(mcsz >= 7*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \
wdenk8bde7f72003-06-27 21:31:46 +0000418 *mcdst++ = *mcsrc++; \
419 if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \
420 *mcdst++ = *mcsrc++; }}} \
421 *mcdst++ = *mcsrc++; \
422 *mcdst++ = *mcsrc++; \
423 *mcdst = *mcsrc ; \
wdenk217c9da2002-10-25 20:35:49 +0000424 } else memcpy(dest, src, mcsz); \
425} while(0)
426
427#else /* !USE_MEMCPY */
428
429/* Use Duff's device for good zeroing/copying performance. */
430
431#define MALLOC_ZERO(charp, nbytes) \
432do { \
433 INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \
434 long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \
435 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \
436 switch (mctmp) { \
437 case 0: for(;;) { *mzp++ = 0; \
438 case 7: *mzp++ = 0; \
439 case 6: *mzp++ = 0; \
440 case 5: *mzp++ = 0; \
441 case 4: *mzp++ = 0; \
442 case 3: *mzp++ = 0; \
443 case 2: *mzp++ = 0; \
444 case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \
445 } \
446} while(0)
447
448#define MALLOC_COPY(dest,src,nbytes) \
449do { \
450 INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \
451 INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \
452 long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \
453 if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \
454 switch (mctmp) { \
455 case 0: for(;;) { *mcdst++ = *mcsrc++; \
456 case 7: *mcdst++ = *mcsrc++; \
457 case 6: *mcdst++ = *mcsrc++; \
458 case 5: *mcdst++ = *mcsrc++; \
459 case 4: *mcdst++ = *mcsrc++; \
460 case 3: *mcdst++ = *mcsrc++; \
461 case 2: *mcdst++ = *mcsrc++; \
462 case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \
463 } \
464} while(0)
465
466#endif
467
468
469/*
470 Define HAVE_MMAP to optionally make malloc() use mmap() to
471 allocate very large blocks. These will be returned to the
472 operating system immediately after a free().
473*/
474
475#ifndef HAVE_MMAP
476#define HAVE_MMAP 1
477#endif
478
479/*
480 Define HAVE_MREMAP to make realloc() use mremap() to re-allocate
481 large blocks. This is currently only possible on Linux with
482 kernel versions newer than 1.3.77.
483*/
484
485#ifndef HAVE_MREMAP
486#ifdef INTERNAL_LINUX_C_LIB
487#define HAVE_MREMAP 1
488#else
489#define HAVE_MREMAP 0
490#endif
491#endif
492
493#if HAVE_MMAP
494
495#include <unistd.h>
496#include <fcntl.h>
497#include <sys/mman.h>
498
499#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
500#define MAP_ANONYMOUS MAP_ANON
501#endif
502
503#endif /* HAVE_MMAP */
504
505/*
506 Access to system page size. To the extent possible, this malloc
507 manages memory from the system in page-size units.
508
509 The following mechanics for getpagesize were adapted from
510 bsd/gnu getpagesize.h
511*/
512
513#ifndef LACKS_UNISTD_H
514# include <unistd.h>
515#endif
516
517#ifndef malloc_getpagesize
518# ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */
519# ifndef _SC_PAGE_SIZE
520# define _SC_PAGE_SIZE _SC_PAGESIZE
521# endif
522# endif
523# ifdef _SC_PAGE_SIZE
524# define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
525# else
526# if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
527 extern size_t getpagesize();
528# define malloc_getpagesize getpagesize()
529# else
530# ifdef WIN32
531# define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */
532# else
533# ifndef LACKS_SYS_PARAM_H
534# include <sys/param.h>
535# endif
536# ifdef EXEC_PAGESIZE
537# define malloc_getpagesize EXEC_PAGESIZE
538# else
539# ifdef NBPG
540# ifndef CLSIZE
541# define malloc_getpagesize NBPG
542# else
543# define malloc_getpagesize (NBPG * CLSIZE)
544# endif
545# else
546# ifdef NBPC
547# define malloc_getpagesize NBPC
548# else
549# ifdef PAGESIZE
550# define malloc_getpagesize PAGESIZE
551# else
552# define malloc_getpagesize (4096) /* just guess */
553# endif
554# endif
555# endif
556# endif
557# endif
558# endif
559# endif
560#endif
561
562
wdenk217c9da2002-10-25 20:35:49 +0000563/*
564
565 This version of malloc supports the standard SVID/XPG mallinfo
566 routine that returns a struct containing the same kind of
567 information you can get from malloc_stats. It should work on
568 any SVID/XPG compliant system that has a /usr/include/malloc.h
569 defining struct mallinfo. (If you'd like to install such a thing
570 yourself, cut out the preliminary declarations as described above
571 and below and save them in a malloc.h file. But there's no
572 compelling reason to bother to do this.)
573
574 The main declaration needed is the mallinfo struct that is returned
575 (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a
576 bunch of fields, most of which are not even meaningful in this
577 version of malloc. Some of these fields are are instead filled by
578 mallinfo() with other numbers that might possibly be of interest.
579
580 HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
581 /usr/include/malloc.h file that includes a declaration of struct
582 mallinfo. If so, it is included; else an SVID2/XPG2 compliant
583 version is declared below. These must be precisely the same for
584 mallinfo() to work.
585
586*/
587
588/* #define HAVE_USR_INCLUDE_MALLOC_H */
589
590#if HAVE_USR_INCLUDE_MALLOC_H
591#include "/usr/include/malloc.h"
592#else
593
594/* SVID2/XPG mallinfo structure */
595
596struct mallinfo {
597 int arena; /* total space allocated from system */
598 int ordblks; /* number of non-inuse chunks */
599 int smblks; /* unused -- always zero */
600 int hblks; /* number of mmapped regions */
601 int hblkhd; /* total space in mmapped regions */
602 int usmblks; /* unused -- always zero */
603 int fsmblks; /* unused -- always zero */
604 int uordblks; /* total allocated space */
605 int fordblks; /* total non-inuse space */
606 int keepcost; /* top-most, releasable (via malloc_trim) space */
607};
608
609/* SVID2/XPG mallopt options */
610
611#define M_MXFAST 1 /* UNUSED in this malloc */
612#define M_NLBLKS 2 /* UNUSED in this malloc */
613#define M_GRAIN 3 /* UNUSED in this malloc */
614#define M_KEEP 4 /* UNUSED in this malloc */
615
616#endif
617
618/* mallopt options that actually do something */
619
620#define M_TRIM_THRESHOLD -1
621#define M_TOP_PAD -2
622#define M_MMAP_THRESHOLD -3
623#define M_MMAP_MAX -4
624
625
wdenk217c9da2002-10-25 20:35:49 +0000626#ifndef DEFAULT_TRIM_THRESHOLD
627#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
628#endif
629
630/*
631 M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
632 to keep before releasing via malloc_trim in free().
633
634 Automatic trimming is mainly useful in long-lived programs.
635 Because trimming via sbrk can be slow on some systems, and can
636 sometimes be wasteful (in cases where programs immediately
637 afterward allocate more large chunks) the value should be high
638 enough so that your overall system performance would improve by
639 releasing.
640
641 The trim threshold and the mmap control parameters (see below)
642 can be traded off with one another. Trimming and mmapping are
643 two different ways of releasing unused memory back to the
644 system. Between these two, it is often possible to keep
645 system-level demands of a long-lived program down to a bare
646 minimum. For example, in one test suite of sessions measuring
647 the XF86 X server on Linux, using a trim threshold of 128K and a
648 mmap threshold of 192K led to near-minimal long term resource
649 consumption.
650
651 If you are using this malloc in a long-lived program, it should
652 pay to experiment with these values. As a rough guide, you
653 might set to a value close to the average size of a process
654 (program) running on your system. Releasing this much memory
655 would allow such a process to run in memory. Generally, it's
656 worth it to tune for trimming rather tham memory mapping when a
657 program undergoes phases where several large chunks are
658 allocated and released in ways that can reuse each other's
659 storage, perhaps mixed with phases where there are no such
660 chunks at all. And in well-behaved long-lived programs,
661 controlling release of large blocks via trimming versus mapping
662 is usually faster.
663
664 However, in most programs, these parameters serve mainly as
665 protection against the system-level effects of carrying around
666 massive amounts of unneeded memory. Since frequent calls to
667 sbrk, mmap, and munmap otherwise degrade performance, the default
668 parameters are set to relatively high values that serve only as
669 safeguards.
670
671 The default trim value is high enough to cause trimming only in
672 fairly extreme (by current memory consumption standards) cases.
673 It must be greater than page size to have any useful effect. To
674 disable trimming completely, you can set to (unsigned long)(-1);
675
676
677*/
678
679
680#ifndef DEFAULT_TOP_PAD
681#define DEFAULT_TOP_PAD (0)
682#endif
683
684/*
685 M_TOP_PAD is the amount of extra `padding' space to allocate or
686 retain whenever sbrk is called. It is used in two ways internally:
687
688 * When sbrk is called to extend the top of the arena to satisfy
wdenk8bde7f72003-06-27 21:31:46 +0000689 a new malloc request, this much padding is added to the sbrk
690 request.
wdenk217c9da2002-10-25 20:35:49 +0000691
692 * When malloc_trim is called automatically from free(),
wdenk8bde7f72003-06-27 21:31:46 +0000693 it is used as the `pad' argument.
wdenk217c9da2002-10-25 20:35:49 +0000694
695 In both cases, the actual amount of padding is rounded
696 so that the end of the arena is always a system page boundary.
697
698 The main reason for using padding is to avoid calling sbrk so
699 often. Having even a small pad greatly reduces the likelihood
700 that nearly every malloc request during program start-up (or
701 after trimming) will invoke sbrk, which needlessly wastes
702 time.
703
704 Automatic rounding-up to page-size units is normally sufficient
705 to avoid measurable overhead, so the default is 0. However, in
706 systems where sbrk is relatively slow, it can pay to increase
707 this value, at the expense of carrying around more memory than
708 the program needs.
709
710*/
711
712
713#ifndef DEFAULT_MMAP_THRESHOLD
714#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
715#endif
716
717/*
718
719 M_MMAP_THRESHOLD is the request size threshold for using mmap()
720 to service a request. Requests of at least this size that cannot
721 be allocated using already-existing space will be serviced via mmap.
722 (If enough normal freed space already exists it is used instead.)
723
724 Using mmap segregates relatively large chunks of memory so that
725 they can be individually obtained and released from the host
726 system. A request serviced through mmap is never reused by any
727 other request (at least not directly; the system may just so
728 happen to remap successive requests to the same locations).
729
730 Segregating space in this way has the benefit that mmapped space
731 can ALWAYS be individually released back to the system, which
732 helps keep the system level memory demands of a long-lived
733 program low. Mapped memory can never become `locked' between
734 other chunks, as can happen with normally allocated chunks, which
735 menas that even trimming via malloc_trim would not release them.
736
737 However, it has the disadvantages that:
738
wdenk8bde7f72003-06-27 21:31:46 +0000739 1. The space cannot be reclaimed, consolidated, and then
740 used to service later requests, as happens with normal chunks.
741 2. It can lead to more wastage because of mmap page alignment
742 requirements
743 3. It causes malloc performance to be more dependent on host
744 system memory management support routines which may vary in
745 implementation quality and may impose arbitrary
746 limitations. Generally, servicing a request via normal
747 malloc steps is faster than going through a system's mmap.
wdenk217c9da2002-10-25 20:35:49 +0000748
749 All together, these considerations should lead you to use mmap
750 only for relatively large requests.
751
752
753*/
754
755
wdenk217c9da2002-10-25 20:35:49 +0000756#ifndef DEFAULT_MMAP_MAX
757#if HAVE_MMAP
758#define DEFAULT_MMAP_MAX (64)
759#else
760#define DEFAULT_MMAP_MAX (0)
761#endif
762#endif
763
764/*
765 M_MMAP_MAX is the maximum number of requests to simultaneously
766 service using mmap. This parameter exists because:
767
wdenk8bde7f72003-06-27 21:31:46 +0000768 1. Some systems have a limited number of internal tables for
769 use by mmap.
770 2. In most systems, overreliance on mmap can degrade overall
771 performance.
772 3. If a program allocates many large regions, it is probably
773 better off using normal sbrk-based allocation routines that
774 can reclaim and reallocate normal heap memory. Using a
775 small value allows transition into this mode after the
776 first few allocations.
wdenk217c9da2002-10-25 20:35:49 +0000777
778 Setting to 0 disables all use of mmap. If HAVE_MMAP is not set,
779 the default value is 0, and attempts to set it to non-zero values
780 in mallopt will fail.
781*/
782
783
wdenk217c9da2002-10-25 20:35:49 +0000784/*
785 USE_DL_PREFIX will prefix all public routines with the string 'dl'.
786 Useful to quickly avoid procedure declaration conflicts and linker
787 symbol conflicts with existing memory allocation routines.
788
789*/
790
791/* #define USE_DL_PREFIX */
792
793
wdenk217c9da2002-10-25 20:35:49 +0000794/*
795
796 Special defines for linux libc
797
798 Except when compiled using these special defines for Linux libc
799 using weak aliases, this malloc is NOT designed to work in
800 multithreaded applications. No semaphores or other concurrency
801 control are provided to ensure that multiple malloc or free calls
802 don't run at the same time, which could be disasterous. A single
803 semaphore could be used across malloc, realloc, and free (which is
804 essentially the effect of the linux weak alias approach). It would
805 be hard to obtain finer granularity.
806
807*/
808
809
810#ifdef INTERNAL_LINUX_C_LIB
811
812#if __STD_C
813
814Void_t * __default_morecore_init (ptrdiff_t);
815Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
816
817#else
818
819Void_t * __default_morecore_init ();
820Void_t *(*__morecore)() = __default_morecore_init;
821
822#endif
823
824#define MORECORE (*__morecore)
825#define MORECORE_FAILURE 0
826#define MORECORE_CLEARS 1
827
828#else /* INTERNAL_LINUX_C_LIB */
829
830#if __STD_C
831extern Void_t* sbrk(ptrdiff_t);
832#else
833extern Void_t* sbrk();
834#endif
835
836#ifndef MORECORE
837#define MORECORE sbrk
838#endif
839
840#ifndef MORECORE_FAILURE
841#define MORECORE_FAILURE -1
842#endif
843
844#ifndef MORECORE_CLEARS
845#define MORECORE_CLEARS 1
846#endif
847
848#endif /* INTERNAL_LINUX_C_LIB */
849
850#if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)
851
852#define cALLOc __libc_calloc
853#define fREe __libc_free
854#define mALLOc __libc_malloc
855#define mEMALIGn __libc_memalign
856#define rEALLOc __libc_realloc
857#define vALLOc __libc_valloc
858#define pvALLOc __libc_pvalloc
859#define mALLINFo __libc_mallinfo
860#define mALLOPt __libc_mallopt
861
862#pragma weak calloc = __libc_calloc
863#pragma weak free = __libc_free
864#pragma weak cfree = __libc_free
865#pragma weak malloc = __libc_malloc
866#pragma weak memalign = __libc_memalign
867#pragma weak realloc = __libc_realloc
868#pragma weak valloc = __libc_valloc
869#pragma weak pvalloc = __libc_pvalloc
870#pragma weak mallinfo = __libc_mallinfo
871#pragma weak mallopt = __libc_mallopt
872
873#else
874
875#ifdef USE_DL_PREFIX
876#define cALLOc dlcalloc
877#define fREe dlfree
878#define mALLOc dlmalloc
879#define mEMALIGn dlmemalign
880#define rEALLOc dlrealloc
881#define vALLOc dlvalloc
882#define pvALLOc dlpvalloc
883#define mALLINFo dlmallinfo
884#define mALLOPt dlmallopt
885#else /* USE_DL_PREFIX */
886#define cALLOc calloc
887#define fREe free
888#define mALLOc malloc
889#define mEMALIGn memalign
890#define rEALLOc realloc
891#define vALLOc valloc
892#define pvALLOc pvalloc
893#define mALLINFo mallinfo
894#define mALLOPt mallopt
895#endif /* USE_DL_PREFIX */
896
897#endif
898
899/* Public routines */
900
901#if __STD_C
902
903Void_t* mALLOc(size_t);
904void fREe(Void_t*);
905Void_t* rEALLOc(Void_t*, size_t);
906Void_t* mEMALIGn(size_t, size_t);
907Void_t* vALLOc(size_t);
908Void_t* pvALLOc(size_t);
909Void_t* cALLOc(size_t, size_t);
910void cfree(Void_t*);
911int malloc_trim(size_t);
912size_t malloc_usable_size(Void_t*);
913void malloc_stats();
914int mALLOPt(int, int);
915struct mallinfo mALLINFo(void);
916#else
917Void_t* mALLOc();
918void fREe();
919Void_t* rEALLOc();
920Void_t* mEMALIGn();
921Void_t* vALLOc();
922Void_t* pvALLOc();
923Void_t* cALLOc();
924void cfree();
925int malloc_trim();
926size_t malloc_usable_size();
927void malloc_stats();
928int mALLOPt();
929struct mallinfo mALLINFo();
930#endif
931
932
933#ifdef __cplusplus
934}; /* end of extern "C" */
935#endif
936
937/* ---------- To make a malloc.h, end cutting here ------------ */
938#else /* Moved to malloc.h */
939
940#include <malloc.h>
941#if 0
942#if __STD_C
943static void malloc_update_mallinfo (void);
944void malloc_stats (void);
945#else
946static void malloc_update_mallinfo ();
947void malloc_stats();
948#endif
949#endif /* 0 */
950
951#endif /* 0 */ /* Moved to malloc.h */
wdenk217c9da2002-10-25 20:35:49 +0000952
Wolfgang Denkd87080b2006-03-31 18:32:53 +0200953DECLARE_GLOBAL_DATA_PTR;
954
wdenk217c9da2002-10-25 20:35:49 +0000955/*
956 Emulation of sbrk for WIN32
957 All code within the ifdef WIN32 is untested by me.
958
959 Thanks to Martin Fong and others for supplying this.
960*/
961
962
963#ifdef WIN32
964
965#define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \
966~(malloc_getpagesize-1))
967#define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 1))
968
969/* resrve 64MB to insure large contiguous space */
970#define RESERVED_SIZE (1024*1024*64)
971#define NEXT_SIZE (2048*1024)
972#define TOP_MEMORY ((unsigned long)2*1024*1024*1024)
973
974struct GmListElement;
975typedef struct GmListElement GmListElement;
976
977struct GmListElement
978{
979 GmListElement* next;
980 void* base;
981};
982
983static GmListElement* head = 0;
984static unsigned int gNextAddress = 0;
985static unsigned int gAddressBase = 0;
986static unsigned int gAllocatedSize = 0;
987
988static
989GmListElement* makeGmListElement (void* bas)
990{
991 GmListElement* this;
992 this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement));
993 assert (this);
994 if (this)
995 {
996 this->base = bas;
997 this->next = head;
998 head = this;
999 }
1000 return this;
1001}
1002
1003void gcleanup ()
1004{
1005 BOOL rval;
1006 assert ( (head == NULL) || (head->base == (void*)gAddressBase));
1007 if (gAddressBase && (gNextAddress - gAddressBase))
1008 {
1009 rval = VirtualFree ((void*)gAddressBase,
1010 gNextAddress - gAddressBase,
1011 MEM_DECOMMIT);
wdenk8bde7f72003-06-27 21:31:46 +00001012 assert (rval);
wdenk217c9da2002-10-25 20:35:49 +00001013 }
1014 while (head)
1015 {
1016 GmListElement* next = head->next;
1017 rval = VirtualFree (head->base, 0, MEM_RELEASE);
1018 assert (rval);
1019 LocalFree (head);
1020 head = next;
1021 }
1022}
1023
1024static
1025void* findRegion (void* start_address, unsigned long size)
1026{
1027 MEMORY_BASIC_INFORMATION info;
1028 if (size >= TOP_MEMORY) return NULL;
1029
1030 while ((unsigned long)start_address + size < TOP_MEMORY)
1031 {
1032 VirtualQuery (start_address, &info, sizeof (info));
1033 if ((info.State == MEM_FREE) && (info.RegionSize >= size))
1034 return start_address;
1035 else
1036 {
wdenk8bde7f72003-06-27 21:31:46 +00001037 /* Requested region is not available so see if the */
1038 /* next region is available. Set 'start_address' */
1039 /* to the next region and call 'VirtualQuery()' */
1040 /* again. */
wdenk217c9da2002-10-25 20:35:49 +00001041
1042 start_address = (char*)info.BaseAddress + info.RegionSize;
1043
wdenk8bde7f72003-06-27 21:31:46 +00001044 /* Make sure we start looking for the next region */
1045 /* on the *next* 64K boundary. Otherwise, even if */
1046 /* the new region is free according to */
1047 /* 'VirtualQuery()', the subsequent call to */
1048 /* 'VirtualAlloc()' (which follows the call to */
1049 /* this routine in 'wsbrk()') will round *down* */
1050 /* the requested address to a 64K boundary which */
1051 /* we already know is an address in the */
1052 /* unavailable region. Thus, the subsequent call */
1053 /* to 'VirtualAlloc()' will fail and bring us back */
1054 /* here, causing us to go into an infinite loop. */
wdenk217c9da2002-10-25 20:35:49 +00001055
1056 start_address =
1057 (void *) AlignPage64K((unsigned long) start_address);
1058 }
1059 }
1060 return NULL;
1061
1062}
1063
1064
1065void* wsbrk (long size)
1066{
1067 void* tmp;
1068 if (size > 0)
1069 {
1070 if (gAddressBase == 0)
1071 {
1072 gAllocatedSize = max (RESERVED_SIZE, AlignPage (size));
1073 gNextAddress = gAddressBase =
1074 (unsigned int)VirtualAlloc (NULL, gAllocatedSize,
1075 MEM_RESERVE, PAGE_NOACCESS);
1076 } else if (AlignPage (gNextAddress + size) > (gAddressBase +
1077gAllocatedSize))
1078 {
1079 long new_size = max (NEXT_SIZE, AlignPage (size));
1080 void* new_address = (void*)(gAddressBase+gAllocatedSize);
1081 do
1082 {
1083 new_address = findRegion (new_address, new_size);
1084
1085 if (new_address == 0)
1086 return (void*)-1;
1087
1088 gAddressBase = gNextAddress =
1089 (unsigned int)VirtualAlloc (new_address, new_size,
1090 MEM_RESERVE, PAGE_NOACCESS);
wdenk8bde7f72003-06-27 21:31:46 +00001091 /* repeat in case of race condition */
1092 /* The region that we found has been snagged */
1093 /* by another thread */
wdenk217c9da2002-10-25 20:35:49 +00001094 }
1095 while (gAddressBase == 0);
1096
1097 assert (new_address == (void*)gAddressBase);
1098
1099 gAllocatedSize = new_size;
1100
1101 if (!makeGmListElement ((void*)gAddressBase))
1102 return (void*)-1;
1103 }
1104 if ((size + gNextAddress) > AlignPage (gNextAddress))
1105 {
1106 void* res;
1107 res = VirtualAlloc ((void*)AlignPage (gNextAddress),
1108 (size + gNextAddress -
1109 AlignPage (gNextAddress)),
1110 MEM_COMMIT, PAGE_READWRITE);
1111 if (res == 0)
1112 return (void*)-1;
1113 }
1114 tmp = (void*)gNextAddress;
1115 gNextAddress = (unsigned int)tmp + size;
1116 return tmp;
1117 }
1118 else if (size < 0)
1119 {
1120 unsigned int alignedGoal = AlignPage (gNextAddress + size);
1121 /* Trim by releasing the virtual memory */
1122 if (alignedGoal >= gAddressBase)
1123 {
1124 VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal,
1125 MEM_DECOMMIT);
1126 gNextAddress = gNextAddress + size;
1127 return (void*)gNextAddress;
1128 }
1129 else
1130 {
1131 VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase,
1132 MEM_DECOMMIT);
1133 gNextAddress = gAddressBase;
1134 return (void*)-1;
1135 }
1136 }
1137 else
1138 {
1139 return (void*)gNextAddress;
1140 }
1141}
1142
1143#endif
1144
1145
1146
1147/*
1148 Type declarations
1149*/
1150
1151
1152struct malloc_chunk
1153{
1154 INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */
1155 INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */
1156 struct malloc_chunk* fd; /* double links -- used only if free. */
1157 struct malloc_chunk* bk;
1158};
1159
1160typedef struct malloc_chunk* mchunkptr;
1161
1162/*
1163
1164 malloc_chunk details:
1165
1166 (The following includes lightly edited explanations by Colin Plumb.)
1167
1168 Chunks of memory are maintained using a `boundary tag' method as
1169 described in e.g., Knuth or Standish. (See the paper by Paul
1170 Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a
1171 survey of such techniques.) Sizes of free chunks are stored both
1172 in the front of each chunk and at the end. This makes
1173 consolidating fragmented chunks into bigger chunks very fast. The
1174 size fields also hold bits representing whether chunks are free or
1175 in use.
1176
1177 An allocated chunk looks like this:
1178
1179
1180 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk8bde7f72003-06-27 21:31:46 +00001181 | Size of previous chunk, if allocated | |
1182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1183 | Size of chunk, in bytes |P|
wdenk217c9da2002-10-25 20:35:49 +00001184 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk8bde7f72003-06-27 21:31:46 +00001185 | User data starts here... .
1186 . .
1187 . (malloc_usable_space() bytes) .
1188 . |
wdenk217c9da2002-10-25 20:35:49 +00001189nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk8bde7f72003-06-27 21:31:46 +00001190 | Size of chunk |
1191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk217c9da2002-10-25 20:35:49 +00001192
1193
1194 Where "chunk" is the front of the chunk for the purpose of most of
1195 the malloc code, but "mem" is the pointer that is returned to the
1196 user. "Nextchunk" is the beginning of the next contiguous chunk.
1197
1198 Chunks always begin on even word boundries, so the mem portion
1199 (which is returned to the user) is also on an even word boundary, and
1200 thus double-word aligned.
1201
1202 Free chunks are stored in circular doubly-linked lists, and look like this:
1203
1204 chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk8bde7f72003-06-27 21:31:46 +00001205 | Size of previous chunk |
1206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk217c9da2002-10-25 20:35:49 +00001207 `head:' | Size of chunk, in bytes |P|
1208 mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk8bde7f72003-06-27 21:31:46 +00001209 | Forward pointer to next chunk in list |
1210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1211 | Back pointer to previous chunk in list |
1212 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1213 | Unused space (may be 0 bytes long) .
1214 . .
1215 . |
wdenk217c9da2002-10-25 20:35:49 +00001216nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
1217 `foot:' | Size of chunk, in bytes |
wdenk8bde7f72003-06-27 21:31:46 +00001218 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
wdenk217c9da2002-10-25 20:35:49 +00001219
1220 The P (PREV_INUSE) bit, stored in the unused low-order bit of the
1221 chunk size (which is always a multiple of two words), is an in-use
1222 bit for the *previous* chunk. If that bit is *clear*, then the
1223 word before the current chunk size contains the previous chunk
1224 size, and can be used to find the front of the previous chunk.
1225 (The very first chunk allocated always has this bit set,
1226 preventing access to non-existent (or non-owned) memory.)
1227
1228 Note that the `foot' of the current chunk is actually represented
1229 as the prev_size of the NEXT chunk. (This makes it easier to
1230 deal with alignments etc).
1231
1232 The two exceptions to all this are
1233
1234 1. The special chunk `top', which doesn't bother using the
wdenk8bde7f72003-06-27 21:31:46 +00001235 trailing size field since there is no
1236 next contiguous chunk that would have to index off it. (After
1237 initialization, `top' is forced to always exist. If it would
1238 become less than MINSIZE bytes long, it is replenished via
1239 malloc_extend_top.)
wdenk217c9da2002-10-25 20:35:49 +00001240
1241 2. Chunks allocated via mmap, which have the second-lowest-order
wdenk8bde7f72003-06-27 21:31:46 +00001242 bit (IS_MMAPPED) set in their size fields. Because they are
1243 never merged or traversed from any other chunk, they have no
1244 foot size or inuse information.
wdenk217c9da2002-10-25 20:35:49 +00001245
1246 Available chunks are kept in any of several places (all declared below):
1247
1248 * `av': An array of chunks serving as bin headers for consolidated
1249 chunks. Each bin is doubly linked. The bins are approximately
1250 proportionally (log) spaced. There are a lot of these bins
1251 (128). This may look excessive, but works very well in
1252 practice. All procedures maintain the invariant that no
1253 consolidated chunk physically borders another one. Chunks in
1254 bins are kept in size order, with ties going to the
1255 approximately least recently used chunk.
1256
1257 The chunks in each bin are maintained in decreasing sorted order by
1258 size. This is irrelevant for the small bins, which all contain
1259 the same-sized chunks, but facilitates best-fit allocation for
1260 larger chunks. (These lists are just sequential. Keeping them in
1261 order almost never requires enough traversal to warrant using
1262 fancier ordered data structures.) Chunks of the same size are
1263 linked with the most recently freed at the front, and allocations
1264 are taken from the back. This results in LRU or FIFO allocation
1265 order, which tends to give each chunk an equal opportunity to be
1266 consolidated with adjacent freed chunks, resulting in larger free
1267 chunks and less fragmentation.
1268
1269 * `top': The top-most available chunk (i.e., the one bordering the
1270 end of available memory) is treated specially. It is never
1271 included in any bin, is used only if no other chunk is
1272 available, and is released back to the system if it is very
1273 large (see M_TRIM_THRESHOLD).
1274
1275 * `last_remainder': A bin holding only the remainder of the
1276 most recently split (non-top) chunk. This bin is checked
1277 before other non-fitting chunks, so as to provide better
1278 locality for runs of sequentially allocated chunks.
1279
1280 * Implicitly, through the host system's memory mapping tables.
1281 If supported, requests greater than a threshold are usually
1282 serviced via calls to mmap, and then later released via munmap.
1283
1284*/
wdenk217c9da2002-10-25 20:35:49 +00001285
wdenk217c9da2002-10-25 20:35:49 +00001286/* sizes, alignments */
1287
1288#define SIZE_SZ (sizeof(INTERNAL_SIZE_T))
1289#define MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ)
1290#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
1291#define MINSIZE (sizeof(struct malloc_chunk))
1292
1293/* conversion from malloc headers to user pointers, and back */
1294
1295#define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ))
1296#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
1297
1298/* pad request bytes into a usable size */
1299
1300#define request2size(req) \
1301 (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
1302 (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
1303 (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
1304
1305/* Check if m has acceptable alignment */
1306
1307#define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0)
1308
1309
1310
1311
1312/*
1313 Physical chunk operations
1314*/
1315
1316
1317/* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */
1318
1319#define PREV_INUSE 0x1
1320
1321/* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */
1322
1323#define IS_MMAPPED 0x2
1324
1325/* Bits to mask off when extracting size */
1326
1327#define SIZE_BITS (PREV_INUSE|IS_MMAPPED)
1328
1329
1330/* Ptr to next physical malloc_chunk. */
1331
1332#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) ))
1333
1334/* Ptr to previous physical malloc_chunk */
1335
1336#define prev_chunk(p)\
1337 ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) ))
1338
1339
1340/* Treat space at ptr + offset as a chunk */
1341
1342#define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s)))
1343
1344
1345
1346
1347/*
1348 Dealing with use bits
1349*/
1350
1351/* extract p's inuse bit */
1352
1353#define inuse(p)\
1354((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)
1355
1356/* extract inuse bit of previous chunk */
1357
1358#define prev_inuse(p) ((p)->size & PREV_INUSE)
1359
1360/* check for mmap()'ed chunk */
1361
1362#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
1363
1364/* set/clear chunk as in use without otherwise disturbing */
1365
1366#define set_inuse(p)\
1367((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE
1368
1369#define clear_inuse(p)\
1370((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)
1371
1372/* check/set/clear inuse bits in known places */
1373
1374#define inuse_bit_at_offset(p, s)\
1375 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)
1376
1377#define set_inuse_bit_at_offset(p, s)\
1378 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)
1379
1380#define clear_inuse_bit_at_offset(p, s)\
1381 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))
1382
1383
1384
1385
1386/*
1387 Dealing with size fields
1388*/
1389
1390/* Get size, ignoring use bits */
1391
1392#define chunksize(p) ((p)->size & ~(SIZE_BITS))
1393
1394/* Set size at head, without disturbing its use bit */
1395
1396#define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s)))
1397
1398/* Set size/use ignoring previous bits in header */
1399
1400#define set_head(p, s) ((p)->size = (s))
1401
1402/* Set size at footer (only when chunk is not in use) */
1403
1404#define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))
1405
1406
1407
1408
1409
1410/*
1411 Bins
1412
1413 The bins, `av_' are an array of pairs of pointers serving as the
1414 heads of (initially empty) doubly-linked lists of chunks, laid out
1415 in a way so that each pair can be treated as if it were in a
1416 malloc_chunk. (This way, the fd/bk offsets for linking bin heads
1417 and chunks are the same).
1418
1419 Bins for sizes < 512 bytes contain chunks of all the same size, spaced
1420 8 bytes apart. Larger bins are approximately logarithmically
1421 spaced. (See the table below.) The `av_' array is never mentioned
1422 directly in the code, but instead via bin access macros.
1423
1424 Bin layout:
1425
1426 64 bins of size 8
1427 32 bins of size 64
1428 16 bins of size 512
1429 8 bins of size 4096
1430 4 bins of size 32768
1431 2 bins of size 262144
1432 1 bin of size what's left
1433
1434 There is actually a little bit of slop in the numbers in bin_index
1435 for the sake of speed. This makes no difference elsewhere.
1436
1437 The special chunks `top' and `last_remainder' get their own bins,
1438 (this is implemented via yet more trickery with the av_ array),
1439 although `top' is never properly linked to its bin since it is
1440 always handled specially.
1441
1442*/
1443
1444#define NAV 128 /* number of bins */
1445
1446typedef struct malloc_chunk* mbinptr;
1447
1448/* access macros */
1449
1450#define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
1451#define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
1452#define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))
1453
1454/*
1455 The first 2 bins are never indexed. The corresponding av_ cells are instead
1456 used for bookkeeping. This is not to save space, but to simplify
1457 indexing, maintain locality, and avoid some initialization tests.
1458*/
1459
Stefan Roesef2302d42008-08-06 14:05:38 +02001460#define top (av_[2]) /* The topmost chunk */
wdenk217c9da2002-10-25 20:35:49 +00001461#define last_remainder (bin_at(1)) /* remainder from last split */
1462
1463
1464/*
1465 Because top initially points to its own bin with initial
1466 zero size, thus forcing extension on the first malloc request,
1467 we avoid having any special code in malloc to check whether
1468 it even exists yet. But we still need to in malloc_extend_top.
1469*/
1470
1471#define initial_top ((mchunkptr)(bin_at(0)))
1472
1473/* Helper macro to initialize bins */
1474
1475#define IAV(i) bin_at(i), bin_at(i)
1476
1477static mbinptr av_[NAV * 2 + 2] = {
1478 0, 0,
1479 IAV(0), IAV(1), IAV(2), IAV(3), IAV(4), IAV(5), IAV(6), IAV(7),
1480 IAV(8), IAV(9), IAV(10), IAV(11), IAV(12), IAV(13), IAV(14), IAV(15),
1481 IAV(16), IAV(17), IAV(18), IAV(19), IAV(20), IAV(21), IAV(22), IAV(23),
1482 IAV(24), IAV(25), IAV(26), IAV(27), IAV(28), IAV(29), IAV(30), IAV(31),
1483 IAV(32), IAV(33), IAV(34), IAV(35), IAV(36), IAV(37), IAV(38), IAV(39),
1484 IAV(40), IAV(41), IAV(42), IAV(43), IAV(44), IAV(45), IAV(46), IAV(47),
1485 IAV(48), IAV(49), IAV(50), IAV(51), IAV(52), IAV(53), IAV(54), IAV(55),
1486 IAV(56), IAV(57), IAV(58), IAV(59), IAV(60), IAV(61), IAV(62), IAV(63),
1487 IAV(64), IAV(65), IAV(66), IAV(67), IAV(68), IAV(69), IAV(70), IAV(71),
1488 IAV(72), IAV(73), IAV(74), IAV(75), IAV(76), IAV(77), IAV(78), IAV(79),
1489 IAV(80), IAV(81), IAV(82), IAV(83), IAV(84), IAV(85), IAV(86), IAV(87),
1490 IAV(88), IAV(89), IAV(90), IAV(91), IAV(92), IAV(93), IAV(94), IAV(95),
1491 IAV(96), IAV(97), IAV(98), IAV(99), IAV(100), IAV(101), IAV(102), IAV(103),
1492 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
1493 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
1494 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
1495};
1496
1497void malloc_bin_reloc (void)
1498{
wdenk217c9da2002-10-25 20:35:49 +00001499 unsigned long *p = (unsigned long *)(&av_[2]);
1500 int i;
1501 for (i=2; i<(sizeof(av_)/sizeof(mbinptr)); ++i) {
1502 *p++ += gd->reloc_off;
1503 }
1504}
1505
1506
1507/* field-extraction macros */
1508
1509#define first(b) ((b)->fd)
1510#define last(b) ((b)->bk)
1511
1512/*
1513 Indexing into bins
1514*/
1515
1516#define bin_index(sz) \
1517(((((unsigned long)(sz)) >> 9) == 0) ? (((unsigned long)(sz)) >> 3): \
1518 ((((unsigned long)(sz)) >> 9) <= 4) ? 56 + (((unsigned long)(sz)) >> 6): \
1519 ((((unsigned long)(sz)) >> 9) <= 20) ? 91 + (((unsigned long)(sz)) >> 9): \
1520 ((((unsigned long)(sz)) >> 9) <= 84) ? 110 + (((unsigned long)(sz)) >> 12): \
1521 ((((unsigned long)(sz)) >> 9) <= 340) ? 119 + (((unsigned long)(sz)) >> 15): \
1522 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
wdenk8bde7f72003-06-27 21:31:46 +00001523 126)
wdenk217c9da2002-10-25 20:35:49 +00001524/*
1525 bins for chunks < 512 are all spaced 8 bytes apart, and hold
1526 identically sized chunks. This is exploited in malloc.
1527*/
1528
1529#define MAX_SMALLBIN 63
1530#define MAX_SMALLBIN_SIZE 512
1531#define SMALLBIN_WIDTH 8
1532
1533#define smallbin_index(sz) (((unsigned long)(sz)) >> 3)
1534
1535/*
1536 Requests are `small' if both the corresponding and the next bin are small
1537*/
1538
1539#define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)
1540
1541
1542
1543/*
1544 To help compensate for the large number of bins, a one-level index
1545 structure is used for bin-by-bin searching. `binblocks' is a
1546 one-word bitvector recording whether groups of BINBLOCKWIDTH bins
1547 have any (possibly) non-empty bins, so they can be skipped over
1548 all at once during during traversals. The bits are NOT always
1549 cleared as soon as all bins in a block are empty, but instead only
1550 when all are noticed to be empty during traversal in malloc.
1551*/
1552
1553#define BINBLOCKWIDTH 4 /* bins per block */
1554
Stefan Roesef2302d42008-08-06 14:05:38 +02001555#define binblocks_r ((INTERNAL_SIZE_T)av_[1]) /* bitvector of nonempty blocks */
1556#define binblocks_w (av_[1])
wdenk217c9da2002-10-25 20:35:49 +00001557
1558/* bin<->block macros */
1559
1560#define idx2binblock(ix) ((unsigned)1 << (ix / BINBLOCKWIDTH))
Stefan Roesef2302d42008-08-06 14:05:38 +02001561#define mark_binblock(ii) (binblocks_w = (mbinptr)(binblocks_r | idx2binblock(ii)))
1562#define clear_binblock(ii) (binblocks_w = (mbinptr)(binblocks_r & ~(idx2binblock(ii))))
wdenk217c9da2002-10-25 20:35:49 +00001563
1564
1565
1566
1567
1568/* Other static bookkeeping data */
1569
1570/* variables holding tunable values */
1571
1572static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD;
1573static unsigned long top_pad = DEFAULT_TOP_PAD;
1574static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX;
1575static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD;
1576
1577/* The first value returned from sbrk */
1578static char* sbrk_base = (char*)(-1);
1579
1580/* The maximum memory obtained from system via sbrk */
1581static unsigned long max_sbrked_mem = 0;
1582
1583/* The maximum via either sbrk or mmap */
1584static unsigned long max_total_mem = 0;
1585
1586/* internal working copy of mallinfo */
1587static struct mallinfo current_mallinfo = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
1588
1589/* The total memory obtained from system via sbrk */
1590#define sbrked_mem (current_mallinfo.arena)
1591
1592/* Tracking mmaps */
1593
1594#if 0
1595static unsigned int n_mmaps = 0;
1596#endif /* 0 */
1597static unsigned long mmapped_mem = 0;
1598#if HAVE_MMAP
1599static unsigned int max_n_mmaps = 0;
1600static unsigned long max_mmapped_mem = 0;
1601#endif
1602
1603
1604
1605/*
1606 Debugging support
1607*/
1608
1609#ifdef DEBUG
1610
1611
1612/*
1613 These routines make a number of assertions about the states
1614 of data structures that should be true at all times. If any
1615 are not true, it's very likely that a user program has somehow
1616 trashed memory. (It's also possible that there is a coding error
1617 in malloc. In which case, please report it!)
1618*/
1619
1620#if __STD_C
1621static void do_check_chunk(mchunkptr p)
1622#else
1623static void do_check_chunk(p) mchunkptr p;
1624#endif
1625{
1626#if 0 /* causes warnings because assert() is off */
1627 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1628#endif /* 0 */
1629
1630 /* No checkable chunk is mmapped */
1631 assert(!chunk_is_mmapped(p));
1632
1633 /* Check for legal address ... */
1634 assert((char*)p >= sbrk_base);
1635 if (p != top)
1636 assert((char*)p + sz <= (char*)top);
1637 else
1638 assert((char*)p + sz <= sbrk_base + sbrked_mem);
1639
1640}
1641
1642
1643#if __STD_C
1644static void do_check_free_chunk(mchunkptr p)
1645#else
1646static void do_check_free_chunk(p) mchunkptr p;
1647#endif
1648{
1649 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1650#if 0 /* causes warnings because assert() is off */
1651 mchunkptr next = chunk_at_offset(p, sz);
1652#endif /* 0 */
1653
1654 do_check_chunk(p);
1655
1656 /* Check whether it claims to be free ... */
1657 assert(!inuse(p));
1658
1659 /* Unless a special marker, must have OK fields */
1660 if ((long)sz >= (long)MINSIZE)
1661 {
1662 assert((sz & MALLOC_ALIGN_MASK) == 0);
1663 assert(aligned_OK(chunk2mem(p)));
1664 /* ... matching footer field */
1665 assert(next->prev_size == sz);
1666 /* ... and is fully consolidated */
1667 assert(prev_inuse(p));
1668 assert (next == top || inuse(next));
1669
1670 /* ... and has minimally sane links */
1671 assert(p->fd->bk == p);
1672 assert(p->bk->fd == p);
1673 }
1674 else /* markers are always of size SIZE_SZ */
1675 assert(sz == SIZE_SZ);
1676}
1677
1678#if __STD_C
1679static void do_check_inuse_chunk(mchunkptr p)
1680#else
1681static void do_check_inuse_chunk(p) mchunkptr p;
1682#endif
1683{
1684 mchunkptr next = next_chunk(p);
1685 do_check_chunk(p);
1686
1687 /* Check whether it claims to be in use ... */
1688 assert(inuse(p));
1689
1690 /* ... and is surrounded by OK chunks.
1691 Since more things can be checked with free chunks than inuse ones,
1692 if an inuse chunk borders them and debug is on, it's worth doing them.
1693 */
1694 if (!prev_inuse(p))
1695 {
1696 mchunkptr prv = prev_chunk(p);
1697 assert(next_chunk(prv) == p);
1698 do_check_free_chunk(prv);
1699 }
1700 if (next == top)
1701 {
1702 assert(prev_inuse(next));
1703 assert(chunksize(next) >= MINSIZE);
1704 }
1705 else if (!inuse(next))
1706 do_check_free_chunk(next);
1707
1708}
1709
1710#if __STD_C
1711static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s)
1712#else
1713static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s;
1714#endif
1715{
1716#if 0 /* causes warnings because assert() is off */
1717 INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
1718 long room = sz - s;
1719#endif /* 0 */
1720
1721 do_check_inuse_chunk(p);
1722
1723 /* Legal size ... */
1724 assert((long)sz >= (long)MINSIZE);
1725 assert((sz & MALLOC_ALIGN_MASK) == 0);
1726 assert(room >= 0);
1727 assert(room < (long)MINSIZE);
1728
1729 /* ... and alignment */
1730 assert(aligned_OK(chunk2mem(p)));
1731
1732
1733 /* ... and was allocated at front of an available chunk */
1734 assert(prev_inuse(p));
1735
1736}
1737
1738
1739#define check_free_chunk(P) do_check_free_chunk(P)
1740#define check_inuse_chunk(P) do_check_inuse_chunk(P)
1741#define check_chunk(P) do_check_chunk(P)
1742#define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N)
1743#else
1744#define check_free_chunk(P)
1745#define check_inuse_chunk(P)
1746#define check_chunk(P)
1747#define check_malloced_chunk(P,N)
1748#endif
1749
1750
1751
1752/*
1753 Macro-based internal utilities
1754*/
1755
1756
1757/*
1758 Linking chunks in bin lists.
1759 Call these only with variables, not arbitrary expressions, as arguments.
1760*/
1761
1762/*
1763 Place chunk p of size s in its bin, in size order,
1764 putting it ahead of others of same size.
1765*/
1766
1767
1768#define frontlink(P, S, IDX, BK, FD) \
1769{ \
1770 if (S < MAX_SMALLBIN_SIZE) \
1771 { \
1772 IDX = smallbin_index(S); \
1773 mark_binblock(IDX); \
1774 BK = bin_at(IDX); \
1775 FD = BK->fd; \
1776 P->bk = BK; \
1777 P->fd = FD; \
1778 FD->bk = BK->fd = P; \
1779 } \
1780 else \
1781 { \
1782 IDX = bin_index(S); \
1783 BK = bin_at(IDX); \
1784 FD = BK->fd; \
1785 if (FD == BK) mark_binblock(IDX); \
1786 else \
1787 { \
1788 while (FD != BK && S < chunksize(FD)) FD = FD->fd; \
1789 BK = FD->bk; \
1790 } \
1791 P->bk = BK; \
1792 P->fd = FD; \
1793 FD->bk = BK->fd = P; \
1794 } \
1795}
1796
1797
1798/* take a chunk off a list */
1799
1800#define unlink(P, BK, FD) \
1801{ \
1802 BK = P->bk; \
1803 FD = P->fd; \
1804 FD->bk = BK; \
1805 BK->fd = FD; \
1806} \
1807
1808/* Place p as the last remainder */
1809
1810#define link_last_remainder(P) \
1811{ \
1812 last_remainder->fd = last_remainder->bk = P; \
1813 P->fd = P->bk = last_remainder; \
1814}
1815
1816/* Clear the last_remainder bin */
1817
1818#define clear_last_remainder \
1819 (last_remainder->fd = last_remainder->bk = last_remainder)
1820
1821
wdenk217c9da2002-10-25 20:35:49 +00001822
1823
1824
1825/* Routines dealing with mmap(). */
1826
1827#if HAVE_MMAP
1828
1829#if __STD_C
1830static mchunkptr mmap_chunk(size_t size)
1831#else
1832static mchunkptr mmap_chunk(size) size_t size;
1833#endif
1834{
1835 size_t page_mask = malloc_getpagesize - 1;
1836 mchunkptr p;
1837
1838#ifndef MAP_ANONYMOUS
1839 static int fd = -1;
1840#endif
1841
1842 if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */
1843
1844 /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
1845 * there is no following chunk whose prev_size field could be used.
1846 */
1847 size = (size + SIZE_SZ + page_mask) & ~page_mask;
1848
1849#ifdef MAP_ANONYMOUS
1850 p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE,
1851 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
1852#else /* !MAP_ANONYMOUS */
1853 if (fd < 0)
1854 {
1855 fd = open("/dev/zero", O_RDWR);
1856 if(fd < 0) return 0;
1857 }
1858 p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
1859#endif
1860
1861 if(p == (mchunkptr)-1) return 0;
1862
1863 n_mmaps++;
1864 if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps;
1865
1866 /* We demand that eight bytes into a page must be 8-byte aligned. */
1867 assert(aligned_OK(chunk2mem(p)));
1868
1869 /* The offset to the start of the mmapped region is stored
1870 * in the prev_size field of the chunk; normally it is zero,
1871 * but that can be changed in memalign().
1872 */
1873 p->prev_size = 0;
1874 set_head(p, size|IS_MMAPPED);
1875
1876 mmapped_mem += size;
1877 if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1878 max_mmapped_mem = mmapped_mem;
1879 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1880 max_total_mem = mmapped_mem + sbrked_mem;
1881 return p;
1882}
1883
1884#if __STD_C
1885static void munmap_chunk(mchunkptr p)
1886#else
1887static void munmap_chunk(p) mchunkptr p;
1888#endif
1889{
1890 INTERNAL_SIZE_T size = chunksize(p);
1891 int ret;
1892
1893 assert (chunk_is_mmapped(p));
1894 assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1895 assert((n_mmaps > 0));
1896 assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0);
1897
1898 n_mmaps--;
1899 mmapped_mem -= (size + p->prev_size);
1900
1901 ret = munmap((char *)p - p->prev_size, size + p->prev_size);
1902
1903 /* munmap returns non-zero on failure */
1904 assert(ret == 0);
1905}
1906
1907#if HAVE_MREMAP
1908
1909#if __STD_C
1910static mchunkptr mremap_chunk(mchunkptr p, size_t new_size)
1911#else
1912static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size;
1913#endif
1914{
1915 size_t page_mask = malloc_getpagesize - 1;
1916 INTERNAL_SIZE_T offset = p->prev_size;
1917 INTERNAL_SIZE_T size = chunksize(p);
1918 char *cp;
1919
1920 assert (chunk_is_mmapped(p));
1921 assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem));
1922 assert((n_mmaps > 0));
1923 assert(((size + offset) & (malloc_getpagesize-1)) == 0);
1924
1925 /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
1926 new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask;
1927
1928 cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1);
1929
1930 if (cp == (char *)-1) return 0;
1931
1932 p = (mchunkptr)(cp + offset);
1933
1934 assert(aligned_OK(chunk2mem(p)));
1935
1936 assert((p->prev_size == offset));
1937 set_head(p, (new_size - offset)|IS_MMAPPED);
1938
1939 mmapped_mem -= size + offset;
1940 mmapped_mem += new_size;
1941 if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem)
1942 max_mmapped_mem = mmapped_mem;
1943 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
1944 max_total_mem = mmapped_mem + sbrked_mem;
1945 return p;
1946}
1947
1948#endif /* HAVE_MREMAP */
1949
1950#endif /* HAVE_MMAP */
1951
1952
1953
1954
1955/*
1956 Extend the top-most chunk by obtaining memory from system.
1957 Main interface to sbrk (but see also malloc_trim).
1958*/
1959
1960#if __STD_C
1961static void malloc_extend_top(INTERNAL_SIZE_T nb)
1962#else
1963static void malloc_extend_top(nb) INTERNAL_SIZE_T nb;
1964#endif
1965{
1966 char* brk; /* return value from sbrk */
1967 INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */
1968 INTERNAL_SIZE_T correction; /* bytes for 2nd sbrk call */
1969 char* new_brk; /* return of 2nd sbrk call */
1970 INTERNAL_SIZE_T top_size; /* new size of top chunk */
1971
1972 mchunkptr old_top = top; /* Record state of old top */
1973 INTERNAL_SIZE_T old_top_size = chunksize(old_top);
1974 char* old_end = (char*)(chunk_at_offset(old_top, old_top_size));
1975
1976 /* Pad request with top_pad plus minimal overhead */
1977
1978 INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE;
1979 unsigned long pagesz = malloc_getpagesize;
1980
1981 /* If not the first time through, round to preserve page boundary */
1982 /* Otherwise, we need to correct to a page size below anyway. */
1983 /* (We also correct below if an intervening foreign sbrk call.) */
1984
1985 if (sbrk_base != (char*)(-1))
1986 sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1);
1987
1988 brk = (char*)(MORECORE (sbrk_size));
1989
1990 /* Fail if sbrk failed or if a foreign sbrk call killed our space */
1991 if (brk == (char*)(MORECORE_FAILURE) ||
1992 (brk < old_end && old_top != initial_top))
1993 return;
1994
1995 sbrked_mem += sbrk_size;
1996
1997 if (brk == old_end) /* can just add bytes to current top */
1998 {
1999 top_size = sbrk_size + old_top_size;
2000 set_head(top, top_size | PREV_INUSE);
2001 }
2002 else
2003 {
2004 if (sbrk_base == (char*)(-1)) /* First time through. Record base */
2005 sbrk_base = brk;
2006 else /* Someone else called sbrk(). Count those bytes as sbrked_mem. */
2007 sbrked_mem += brk - (char*)old_end;
2008
2009 /* Guarantee alignment of first new chunk made from this space */
2010 front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
2011 if (front_misalign > 0)
2012 {
2013 correction = (MALLOC_ALIGNMENT) - front_misalign;
2014 brk += correction;
2015 }
2016 else
2017 correction = 0;
2018
2019 /* Guarantee the next brk will be at a page boundary */
2020
2021 correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) &
wdenk8bde7f72003-06-27 21:31:46 +00002022 ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size));
wdenk217c9da2002-10-25 20:35:49 +00002023
2024 /* Allocate correction */
2025 new_brk = (char*)(MORECORE (correction));
2026 if (new_brk == (char*)(MORECORE_FAILURE)) return;
2027
2028 sbrked_mem += correction;
2029
2030 top = (mchunkptr)brk;
2031 top_size = new_brk - brk + correction;
2032 set_head(top, top_size | PREV_INUSE);
2033
2034 if (old_top != initial_top)
2035 {
2036
2037 /* There must have been an intervening foreign sbrk call. */
2038 /* A double fencepost is necessary to prevent consolidation */
2039
2040 /* If not enough space to do this, then user did something very wrong */
2041 if (old_top_size < MINSIZE)
2042 {
wdenk8bde7f72003-06-27 21:31:46 +00002043 set_head(top, PREV_INUSE); /* will force null return from malloc */
2044 return;
wdenk217c9da2002-10-25 20:35:49 +00002045 }
2046
2047 /* Also keep size a multiple of MALLOC_ALIGNMENT */
2048 old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
2049 set_head_size(old_top, old_top_size);
2050 chunk_at_offset(old_top, old_top_size )->size =
wdenk8bde7f72003-06-27 21:31:46 +00002051 SIZE_SZ|PREV_INUSE;
wdenk217c9da2002-10-25 20:35:49 +00002052 chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size =
wdenk8bde7f72003-06-27 21:31:46 +00002053 SIZE_SZ|PREV_INUSE;
wdenk217c9da2002-10-25 20:35:49 +00002054 /* If possible, release the rest. */
2055 if (old_top_size >= MINSIZE)
wdenk8bde7f72003-06-27 21:31:46 +00002056 fREe(chunk2mem(old_top));
wdenk217c9da2002-10-25 20:35:49 +00002057 }
2058 }
2059
2060 if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem)
2061 max_sbrked_mem = sbrked_mem;
2062 if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem)
2063 max_total_mem = mmapped_mem + sbrked_mem;
2064
2065 /* We always land on a page boundary */
2066 assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0);
2067}
2068
2069
2070
2071
2072/* Main public routines */
2073
2074
2075/*
2076 Malloc Algorthim:
2077
2078 The requested size is first converted into a usable form, `nb'.
2079 This currently means to add 4 bytes overhead plus possibly more to
2080 obtain 8-byte alignment and/or to obtain a size of at least
2081 MINSIZE (currently 16 bytes), the smallest allocatable size.
2082 (All fits are considered `exact' if they are within MINSIZE bytes.)
2083
2084 From there, the first successful of the following steps is taken:
2085
2086 1. The bin corresponding to the request size is scanned, and if
wdenk8bde7f72003-06-27 21:31:46 +00002087 a chunk of exactly the right size is found, it is taken.
wdenk217c9da2002-10-25 20:35:49 +00002088
2089 2. The most recently remaindered chunk is used if it is big
wdenk8bde7f72003-06-27 21:31:46 +00002090 enough. This is a form of (roving) first fit, used only in
2091 the absence of exact fits. Runs of consecutive requests use
2092 the remainder of the chunk used for the previous such request
2093 whenever possible. This limited use of a first-fit style
2094 allocation strategy tends to give contiguous chunks
2095 coextensive lifetimes, which improves locality and can reduce
2096 fragmentation in the long run.
wdenk217c9da2002-10-25 20:35:49 +00002097
2098 3. Other bins are scanned in increasing size order, using a
wdenk8bde7f72003-06-27 21:31:46 +00002099 chunk big enough to fulfill the request, and splitting off
2100 any remainder. This search is strictly by best-fit; i.e.,
2101 the smallest (with ties going to approximately the least
2102 recently used) chunk that fits is selected.
wdenk217c9da2002-10-25 20:35:49 +00002103
2104 4. If large enough, the chunk bordering the end of memory
wdenk8bde7f72003-06-27 21:31:46 +00002105 (`top') is split off. (This use of `top' is in accord with
2106 the best-fit search rule. In effect, `top' is treated as
2107 larger (and thus less well fitting) than any other available
2108 chunk since it can be extended to be as large as necessary
2109 (up to system limitations).
wdenk217c9da2002-10-25 20:35:49 +00002110
2111 5. If the request size meets the mmap threshold and the
wdenk8bde7f72003-06-27 21:31:46 +00002112 system supports mmap, and there are few enough currently
2113 allocated mmapped regions, and a call to mmap succeeds,
2114 the request is allocated via direct memory mapping.
wdenk217c9da2002-10-25 20:35:49 +00002115
2116 6. Otherwise, the top of memory is extended by
wdenk8bde7f72003-06-27 21:31:46 +00002117 obtaining more space from the system (normally using sbrk,
2118 but definable to anything else via the MORECORE macro).
2119 Memory is gathered from the system (in system page-sized
2120 units) in a way that allows chunks obtained across different
2121 sbrk calls to be consolidated, but does not require
2122 contiguous memory. Thus, it should be safe to intersperse
2123 mallocs with other sbrk calls.
wdenk217c9da2002-10-25 20:35:49 +00002124
2125
2126 All allocations are made from the the `lowest' part of any found
2127 chunk. (The implementation invariant is that prev_inuse is
2128 always true of any allocated chunk; i.e., that each allocated
2129 chunk borders either a previously allocated and still in-use chunk,
2130 or the base of its memory arena.)
2131
2132*/
2133
2134#if __STD_C
2135Void_t* mALLOc(size_t bytes)
2136#else
2137Void_t* mALLOc(bytes) size_t bytes;
2138#endif
2139{
2140 mchunkptr victim; /* inspected/selected chunk */
2141 INTERNAL_SIZE_T victim_size; /* its size */
2142 int idx; /* index for bin traversal */
2143 mbinptr bin; /* associated bin */
2144 mchunkptr remainder; /* remainder from a split */
2145 long remainder_size; /* its size */
2146 int remainder_index; /* its bin index */
2147 unsigned long block; /* block traverser bit */
2148 int startidx; /* first bin of a traversed block */
2149 mchunkptr fwd; /* misc temp for linking */
2150 mchunkptr bck; /* misc temp for linking */
2151 mbinptr q; /* misc temp */
2152
2153 INTERNAL_SIZE_T nb;
2154
2155 if ((long)bytes < 0) return 0;
2156
2157 nb = request2size(bytes); /* padded request size; */
2158
2159 /* Check for exact match in a bin */
2160
2161 if (is_small_request(nb)) /* Faster version for small requests */
2162 {
2163 idx = smallbin_index(nb);
2164
2165 /* No traversal or size check necessary for small bins. */
2166
2167 q = bin_at(idx);
2168 victim = last(q);
2169
2170 /* Also scan the next one, since it would have a remainder < MINSIZE */
2171 if (victim == q)
2172 {
2173 q = next_bin(q);
2174 victim = last(q);
2175 }
2176 if (victim != q)
2177 {
2178 victim_size = chunksize(victim);
2179 unlink(victim, bck, fwd);
2180 set_inuse_bit_at_offset(victim, victim_size);
2181 check_malloced_chunk(victim, nb);
2182 return chunk2mem(victim);
2183 }
2184
2185 idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */
2186
2187 }
2188 else
2189 {
2190 idx = bin_index(nb);
2191 bin = bin_at(idx);
2192
2193 for (victim = last(bin); victim != bin; victim = victim->bk)
2194 {
2195 victim_size = chunksize(victim);
2196 remainder_size = victim_size - nb;
2197
2198 if (remainder_size >= (long)MINSIZE) /* too big */
2199 {
wdenk8bde7f72003-06-27 21:31:46 +00002200 --idx; /* adjust to rescan below after checking last remainder */
2201 break;
wdenk217c9da2002-10-25 20:35:49 +00002202 }
2203
2204 else if (remainder_size >= 0) /* exact fit */
2205 {
wdenk8bde7f72003-06-27 21:31:46 +00002206 unlink(victim, bck, fwd);
2207 set_inuse_bit_at_offset(victim, victim_size);
2208 check_malloced_chunk(victim, nb);
2209 return chunk2mem(victim);
wdenk217c9da2002-10-25 20:35:49 +00002210 }
2211 }
2212
2213 ++idx;
2214
2215 }
2216
2217 /* Try to use the last split-off remainder */
2218
2219 if ( (victim = last_remainder->fd) != last_remainder)
2220 {
2221 victim_size = chunksize(victim);
2222 remainder_size = victim_size - nb;
2223
2224 if (remainder_size >= (long)MINSIZE) /* re-split */
2225 {
2226 remainder = chunk_at_offset(victim, nb);
2227 set_head(victim, nb | PREV_INUSE);
2228 link_last_remainder(remainder);
2229 set_head(remainder, remainder_size | PREV_INUSE);
2230 set_foot(remainder, remainder_size);
2231 check_malloced_chunk(victim, nb);
2232 return chunk2mem(victim);
2233 }
2234
2235 clear_last_remainder;
2236
2237 if (remainder_size >= 0) /* exhaust */
2238 {
2239 set_inuse_bit_at_offset(victim, victim_size);
2240 check_malloced_chunk(victim, nb);
2241 return chunk2mem(victim);
2242 }
2243
2244 /* Else place in bin */
2245
2246 frontlink(victim, victim_size, remainder_index, bck, fwd);
2247 }
2248
2249 /*
2250 If there are any possibly nonempty big-enough blocks,
2251 search for best fitting chunk by scanning bins in blockwidth units.
2252 */
2253
Stefan Roesef2302d42008-08-06 14:05:38 +02002254 if ( (block = idx2binblock(idx)) <= binblocks_r)
wdenk217c9da2002-10-25 20:35:49 +00002255 {
2256
2257 /* Get to the first marked block */
2258
Stefan Roesef2302d42008-08-06 14:05:38 +02002259 if ( (block & binblocks_r) == 0)
wdenk217c9da2002-10-25 20:35:49 +00002260 {
2261 /* force to an even block boundary */
2262 idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH;
2263 block <<= 1;
Stefan Roesef2302d42008-08-06 14:05:38 +02002264 while ((block & binblocks_r) == 0)
wdenk217c9da2002-10-25 20:35:49 +00002265 {
wdenk8bde7f72003-06-27 21:31:46 +00002266 idx += BINBLOCKWIDTH;
2267 block <<= 1;
wdenk217c9da2002-10-25 20:35:49 +00002268 }
2269 }
2270
2271 /* For each possibly nonempty block ... */
2272 for (;;)
2273 {
2274 startidx = idx; /* (track incomplete blocks) */
2275 q = bin = bin_at(idx);
2276
2277 /* For each bin in this block ... */
2278 do
2279 {
wdenk8bde7f72003-06-27 21:31:46 +00002280 /* Find and use first big enough chunk ... */
wdenk217c9da2002-10-25 20:35:49 +00002281
wdenk8bde7f72003-06-27 21:31:46 +00002282 for (victim = last(bin); victim != bin; victim = victim->bk)
2283 {
2284 victim_size = chunksize(victim);
2285 remainder_size = victim_size - nb;
wdenk217c9da2002-10-25 20:35:49 +00002286
wdenk8bde7f72003-06-27 21:31:46 +00002287 if (remainder_size >= (long)MINSIZE) /* split */
2288 {
2289 remainder = chunk_at_offset(victim, nb);
2290 set_head(victim, nb | PREV_INUSE);
2291 unlink(victim, bck, fwd);
2292 link_last_remainder(remainder);
2293 set_head(remainder, remainder_size | PREV_INUSE);
2294 set_foot(remainder, remainder_size);
2295 check_malloced_chunk(victim, nb);
2296 return chunk2mem(victim);
2297 }
wdenk217c9da2002-10-25 20:35:49 +00002298
wdenk8bde7f72003-06-27 21:31:46 +00002299 else if (remainder_size >= 0) /* take */
2300 {
2301 set_inuse_bit_at_offset(victim, victim_size);
2302 unlink(victim, bck, fwd);
2303 check_malloced_chunk(victim, nb);
2304 return chunk2mem(victim);
2305 }
wdenk217c9da2002-10-25 20:35:49 +00002306
wdenk8bde7f72003-06-27 21:31:46 +00002307 }
wdenk217c9da2002-10-25 20:35:49 +00002308
2309 bin = next_bin(bin);
2310
2311 } while ((++idx & (BINBLOCKWIDTH - 1)) != 0);
2312
2313 /* Clear out the block bit. */
2314
2315 do /* Possibly backtrack to try to clear a partial block */
2316 {
wdenk8bde7f72003-06-27 21:31:46 +00002317 if ((startidx & (BINBLOCKWIDTH - 1)) == 0)
2318 {
Stefan Roesef2302d42008-08-06 14:05:38 +02002319 av_[1] = (mbinptr)(binblocks_r & ~block);
wdenk8bde7f72003-06-27 21:31:46 +00002320 break;
2321 }
2322 --startidx;
wdenk217c9da2002-10-25 20:35:49 +00002323 q = prev_bin(q);
2324 } while (first(q) == q);
2325
2326 /* Get to the next possibly nonempty block */
2327
Stefan Roesef2302d42008-08-06 14:05:38 +02002328 if ( (block <<= 1) <= binblocks_r && (block != 0) )
wdenk217c9da2002-10-25 20:35:49 +00002329 {
Stefan Roesef2302d42008-08-06 14:05:38 +02002330 while ((block & binblocks_r) == 0)
wdenk8bde7f72003-06-27 21:31:46 +00002331 {
2332 idx += BINBLOCKWIDTH;
2333 block <<= 1;
2334 }
wdenk217c9da2002-10-25 20:35:49 +00002335 }
2336 else
wdenk8bde7f72003-06-27 21:31:46 +00002337 break;
wdenk217c9da2002-10-25 20:35:49 +00002338 }
2339 }
2340
2341
2342 /* Try to use top chunk */
2343
2344 /* Require that there be a remainder, ensuring top always exists */
2345 if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
2346 {
2347
2348#if HAVE_MMAP
2349 /* If big and would otherwise need to extend, try to use mmap instead */
2350 if ((unsigned long)nb >= (unsigned long)mmap_threshold &&
wdenk8bde7f72003-06-27 21:31:46 +00002351 (victim = mmap_chunk(nb)) != 0)
wdenk217c9da2002-10-25 20:35:49 +00002352 return chunk2mem(victim);
2353#endif
2354
2355 /* Try to extend */
2356 malloc_extend_top(nb);
2357 if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE)
2358 return 0; /* propagate failure */
2359 }
2360
2361 victim = top;
2362 set_head(victim, nb | PREV_INUSE);
2363 top = chunk_at_offset(victim, nb);
2364 set_head(top, remainder_size | PREV_INUSE);
2365 check_malloced_chunk(victim, nb);
2366 return chunk2mem(victim);
2367
2368}
2369
2370
2371
2372
2373/*
2374
2375 free() algorithm :
2376
2377 cases:
2378
2379 1. free(0) has no effect.
2380
2381 2. If the chunk was allocated via mmap, it is release via munmap().
2382
2383 3. If a returned chunk borders the current high end of memory,
wdenk8bde7f72003-06-27 21:31:46 +00002384 it is consolidated into the top, and if the total unused
2385 topmost memory exceeds the trim threshold, malloc_trim is
2386 called.
wdenk217c9da2002-10-25 20:35:49 +00002387
2388 4. Other chunks are consolidated as they arrive, and
wdenk8bde7f72003-06-27 21:31:46 +00002389 placed in corresponding bins. (This includes the case of
2390 consolidating with the current `last_remainder').
wdenk217c9da2002-10-25 20:35:49 +00002391
2392*/
2393
2394
2395#if __STD_C
2396void fREe(Void_t* mem)
2397#else
2398void fREe(mem) Void_t* mem;
2399#endif
2400{
2401 mchunkptr p; /* chunk corresponding to mem */
2402 INTERNAL_SIZE_T hd; /* its head field */
2403 INTERNAL_SIZE_T sz; /* its size */
2404 int idx; /* its bin index */
2405 mchunkptr next; /* next contiguous chunk */
2406 INTERNAL_SIZE_T nextsz; /* its size */
2407 INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */
2408 mchunkptr bck; /* misc temp for linking */
2409 mchunkptr fwd; /* misc temp for linking */
2410 int islr; /* track whether merging with last_remainder */
2411
2412 if (mem == 0) /* free(0) has no effect */
2413 return;
2414
2415 p = mem2chunk(mem);
2416 hd = p->size;
2417
2418#if HAVE_MMAP
2419 if (hd & IS_MMAPPED) /* release mmapped memory. */
2420 {
2421 munmap_chunk(p);
2422 return;
2423 }
2424#endif
2425
2426 check_inuse_chunk(p);
2427
2428 sz = hd & ~PREV_INUSE;
2429 next = chunk_at_offset(p, sz);
2430 nextsz = chunksize(next);
2431
2432 if (next == top) /* merge with top */
2433 {
2434 sz += nextsz;
2435
2436 if (!(hd & PREV_INUSE)) /* consolidate backward */
2437 {
2438 prevsz = p->prev_size;
2439 p = chunk_at_offset(p, -((long) prevsz));
2440 sz += prevsz;
2441 unlink(p, bck, fwd);
2442 }
2443
2444 set_head(p, sz | PREV_INUSE);
2445 top = p;
2446 if ((unsigned long)(sz) >= (unsigned long)trim_threshold)
2447 malloc_trim(top_pad);
2448 return;
2449 }
2450
2451 set_head(next, nextsz); /* clear inuse bit */
2452
2453 islr = 0;
2454
2455 if (!(hd & PREV_INUSE)) /* consolidate backward */
2456 {
2457 prevsz = p->prev_size;
2458 p = chunk_at_offset(p, -((long) prevsz));
2459 sz += prevsz;
2460
2461 if (p->fd == last_remainder) /* keep as last_remainder */
2462 islr = 1;
2463 else
2464 unlink(p, bck, fwd);
2465 }
2466
2467 if (!(inuse_bit_at_offset(next, nextsz))) /* consolidate forward */
2468 {
2469 sz += nextsz;
2470
2471 if (!islr && next->fd == last_remainder) /* re-insert last_remainder */
2472 {
2473 islr = 1;
2474 link_last_remainder(p);
2475 }
2476 else
2477 unlink(next, bck, fwd);
2478 }
2479
2480
2481 set_head(p, sz | PREV_INUSE);
2482 set_foot(p, sz);
2483 if (!islr)
2484 frontlink(p, sz, idx, bck, fwd);
2485}
2486
2487
2488
2489
2490
2491/*
2492
2493 Realloc algorithm:
2494
2495 Chunks that were obtained via mmap cannot be extended or shrunk
2496 unless HAVE_MREMAP is defined, in which case mremap is used.
2497 Otherwise, if their reallocation is for additional space, they are
2498 copied. If for less, they are just left alone.
2499
2500 Otherwise, if the reallocation is for additional space, and the
2501 chunk can be extended, it is, else a malloc-copy-free sequence is
2502 taken. There are several different ways that a chunk could be
2503 extended. All are tried:
2504
2505 * Extending forward into following adjacent free chunk.
2506 * Shifting backwards, joining preceding adjacent space
2507 * Both shifting backwards and extending forward.
2508 * Extending into newly sbrked space
2509
2510 Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
2511 size argument of zero (re)allocates a minimum-sized chunk.
2512
2513 If the reallocation is for less space, and the new request is for
2514 a `small' (<512 bytes) size, then the newly unused space is lopped
2515 off and freed.
2516
2517 The old unix realloc convention of allowing the last-free'd chunk
2518 to be used as an argument to realloc is no longer supported.
2519 I don't know of any programs still relying on this feature,
2520 and allowing it would also allow too many other incorrect
2521 usages of realloc to be sensible.
2522
2523
2524*/
2525
2526
2527#if __STD_C
2528Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
2529#else
2530Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
2531#endif
2532{
2533 INTERNAL_SIZE_T nb; /* padded request size */
2534
2535 mchunkptr oldp; /* chunk corresponding to oldmem */
2536 INTERNAL_SIZE_T oldsize; /* its size */
2537
2538 mchunkptr newp; /* chunk to return */
2539 INTERNAL_SIZE_T newsize; /* its size */
2540 Void_t* newmem; /* corresponding user mem */
2541
2542 mchunkptr next; /* next contiguous chunk after oldp */
2543 INTERNAL_SIZE_T nextsize; /* its size */
2544
2545 mchunkptr prev; /* previous contiguous chunk before oldp */
2546 INTERNAL_SIZE_T prevsize; /* its size */
2547
2548 mchunkptr remainder; /* holds split off extra space from newp */
2549 INTERNAL_SIZE_T remainder_size; /* its size */
2550
2551 mchunkptr bck; /* misc temp for linking */
2552 mchunkptr fwd; /* misc temp for linking */
2553
2554#ifdef REALLOC_ZERO_BYTES_FREES
2555 if (bytes == 0) { fREe(oldmem); return 0; }
2556#endif
2557
2558 if ((long)bytes < 0) return 0;
2559
2560 /* realloc of null is supposed to be same as malloc */
2561 if (oldmem == 0) return mALLOc(bytes);
2562
2563 newp = oldp = mem2chunk(oldmem);
2564 newsize = oldsize = chunksize(oldp);
2565
2566
2567 nb = request2size(bytes);
2568
2569#if HAVE_MMAP
2570 if (chunk_is_mmapped(oldp))
2571 {
2572#if HAVE_MREMAP
2573 newp = mremap_chunk(oldp, nb);
2574 if(newp) return chunk2mem(newp);
2575#endif
2576 /* Note the extra SIZE_SZ overhead. */
2577 if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
2578 /* Must alloc, copy, free. */
2579 newmem = mALLOc(bytes);
2580 if (newmem == 0) return 0; /* propagate failure */
2581 MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
2582 munmap_chunk(oldp);
2583 return newmem;
2584 }
2585#endif
2586
2587 check_inuse_chunk(oldp);
2588
2589 if ((long)(oldsize) < (long)(nb))
2590 {
2591
2592 /* Try expanding forward */
2593
2594 next = chunk_at_offset(oldp, oldsize);
2595 if (next == top || !inuse(next))
2596 {
2597 nextsize = chunksize(next);
2598
2599 /* Forward into top only if a remainder */
2600 if (next == top)
2601 {
wdenk8bde7f72003-06-27 21:31:46 +00002602 if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE))
2603 {
2604 newsize += nextsize;
2605 top = chunk_at_offset(oldp, nb);
2606 set_head(top, (newsize - nb) | PREV_INUSE);
2607 set_head_size(oldp, nb);
2608 return chunk2mem(oldp);
2609 }
wdenk217c9da2002-10-25 20:35:49 +00002610 }
2611
2612 /* Forward into next chunk */
2613 else if (((long)(nextsize + newsize) >= (long)(nb)))
2614 {
wdenk8bde7f72003-06-27 21:31:46 +00002615 unlink(next, bck, fwd);
2616 newsize += nextsize;
2617 goto split;
wdenk217c9da2002-10-25 20:35:49 +00002618 }
2619 }
2620 else
2621 {
2622 next = 0;
2623 nextsize = 0;
2624 }
2625
2626 /* Try shifting backwards. */
2627
2628 if (!prev_inuse(oldp))
2629 {
2630 prev = prev_chunk(oldp);
2631 prevsize = chunksize(prev);
2632
2633 /* try forward + backward first to save a later consolidation */
2634
2635 if (next != 0)
2636 {
wdenk8bde7f72003-06-27 21:31:46 +00002637 /* into top */
2638 if (next == top)
2639 {
2640 if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE))
2641 {
2642 unlink(prev, bck, fwd);
2643 newp = prev;
2644 newsize += prevsize + nextsize;
2645 newmem = chunk2mem(newp);
2646 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2647 top = chunk_at_offset(newp, nb);
2648 set_head(top, (newsize - nb) | PREV_INUSE);
2649 set_head_size(newp, nb);
2650 return newmem;
2651 }
2652 }
wdenk217c9da2002-10-25 20:35:49 +00002653
wdenk8bde7f72003-06-27 21:31:46 +00002654 /* into next chunk */
2655 else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
2656 {
2657 unlink(next, bck, fwd);
2658 unlink(prev, bck, fwd);
2659 newp = prev;
2660 newsize += nextsize + prevsize;
2661 newmem = chunk2mem(newp);
2662 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2663 goto split;
2664 }
wdenk217c9da2002-10-25 20:35:49 +00002665 }
2666
2667 /* backward only */
2668 if (prev != 0 && (long)(prevsize + newsize) >= (long)nb)
2669 {
wdenk8bde7f72003-06-27 21:31:46 +00002670 unlink(prev, bck, fwd);
2671 newp = prev;
2672 newsize += prevsize;
2673 newmem = chunk2mem(newp);
2674 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2675 goto split;
wdenk217c9da2002-10-25 20:35:49 +00002676 }
2677 }
2678
2679 /* Must allocate */
2680
2681 newmem = mALLOc (bytes);
2682
2683 if (newmem == 0) /* propagate failure */
2684 return 0;
2685
2686 /* Avoid copy if newp is next chunk after oldp. */
2687 /* (This can only happen when new chunk is sbrk'ed.) */
2688
2689 if ( (newp = mem2chunk(newmem)) == next_chunk(oldp))
2690 {
2691 newsize += chunksize(newp);
2692 newp = oldp;
2693 goto split;
2694 }
2695
2696 /* Otherwise copy, free, and exit */
2697 MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
2698 fREe(oldmem);
2699 return newmem;
2700 }
2701
2702
2703 split: /* split off extra room in old or expanded chunk */
2704
2705 if (newsize - nb >= MINSIZE) /* split off remainder */
2706 {
2707 remainder = chunk_at_offset(newp, nb);
2708 remainder_size = newsize - nb;
2709 set_head_size(newp, nb);
2710 set_head(remainder, remainder_size | PREV_INUSE);
2711 set_inuse_bit_at_offset(remainder, remainder_size);
2712 fREe(chunk2mem(remainder)); /* let free() deal with it */
2713 }
2714 else
2715 {
2716 set_head_size(newp, newsize);
2717 set_inuse_bit_at_offset(newp, newsize);
2718 }
2719
2720 check_inuse_chunk(newp);
2721 return chunk2mem(newp);
2722}
2723
2724
2725
2726
2727/*
2728
2729 memalign algorithm:
2730
2731 memalign requests more than enough space from malloc, finds a spot
2732 within that chunk that meets the alignment request, and then
2733 possibly frees the leading and trailing space.
2734
2735 The alignment argument must be a power of two. This property is not
2736 checked by memalign, so misuse may result in random runtime errors.
2737
2738 8-byte alignment is guaranteed by normal malloc calls, so don't
2739 bother calling memalign with an argument of 8 or less.
2740
2741 Overreliance on memalign is a sure way to fragment space.
2742
2743*/
2744
2745
2746#if __STD_C
2747Void_t* mEMALIGn(size_t alignment, size_t bytes)
2748#else
2749Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes;
2750#endif
2751{
2752 INTERNAL_SIZE_T nb; /* padded request size */
2753 char* m; /* memory returned by malloc call */
2754 mchunkptr p; /* corresponding chunk */
2755 char* brk; /* alignment point within p */
2756 mchunkptr newp; /* chunk to return */
2757 INTERNAL_SIZE_T newsize; /* its size */
2758 INTERNAL_SIZE_T leadsize; /* leading space befor alignment point */
2759 mchunkptr remainder; /* spare room at end to split off */
2760 long remainder_size; /* its size */
2761
2762 if ((long)bytes < 0) return 0;
2763
2764 /* If need less alignment than we give anyway, just relay to malloc */
2765
2766 if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes);
2767
2768 /* Otherwise, ensure that it is at least a minimum chunk size */
2769
2770 if (alignment < MINSIZE) alignment = MINSIZE;
2771
2772 /* Call malloc with worst case padding to hit alignment. */
2773
2774 nb = request2size(bytes);
2775 m = (char*)(mALLOc(nb + alignment + MINSIZE));
2776
2777 if (m == 0) return 0; /* propagate failure */
2778
2779 p = mem2chunk(m);
2780
2781 if ((((unsigned long)(m)) % alignment) == 0) /* aligned */
2782 {
2783#if HAVE_MMAP
2784 if(chunk_is_mmapped(p))
2785 return chunk2mem(p); /* nothing more to do */
2786#endif
2787 }
2788 else /* misaligned */
2789 {
2790 /*
2791 Find an aligned spot inside chunk.
2792 Since we need to give back leading space in a chunk of at
2793 least MINSIZE, if the first calculation places us at
2794 a spot with less than MINSIZE leader, we can move to the
2795 next aligned spot -- we've allocated enough total room so that
2796 this is always possible.
2797 */
2798
2799 brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment));
2800 if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment;
2801
2802 newp = (mchunkptr)brk;
2803 leadsize = brk - (char*)(p);
2804 newsize = chunksize(p) - leadsize;
2805
2806#if HAVE_MMAP
2807 if(chunk_is_mmapped(p))
2808 {
2809 newp->prev_size = p->prev_size + leadsize;
2810 set_head(newp, newsize|IS_MMAPPED);
2811 return chunk2mem(newp);
2812 }
2813#endif
2814
2815 /* give back leader, use the rest */
2816
2817 set_head(newp, newsize | PREV_INUSE);
2818 set_inuse_bit_at_offset(newp, newsize);
2819 set_head_size(p, leadsize);
2820 fREe(chunk2mem(p));
2821 p = newp;
2822
2823 assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0);
2824 }
2825
2826 /* Also give back spare room at the end */
2827
2828 remainder_size = chunksize(p) - nb;
2829
2830 if (remainder_size >= (long)MINSIZE)
2831 {
2832 remainder = chunk_at_offset(p, nb);
2833 set_head(remainder, remainder_size | PREV_INUSE);
2834 set_head_size(p, nb);
2835 fREe(chunk2mem(remainder));
2836 }
2837
2838 check_inuse_chunk(p);
2839 return chunk2mem(p);
2840
2841}
2842
2843
2844
2845
2846/*
2847 valloc just invokes memalign with alignment argument equal
2848 to the page size of the system (or as near to this as can
2849 be figured out from all the includes/defines above.)
2850*/
2851
2852#if __STD_C
2853Void_t* vALLOc(size_t bytes)
2854#else
2855Void_t* vALLOc(bytes) size_t bytes;
2856#endif
2857{
2858 return mEMALIGn (malloc_getpagesize, bytes);
2859}
2860
2861/*
2862 pvalloc just invokes valloc for the nearest pagesize
2863 that will accommodate request
2864*/
2865
2866
2867#if __STD_C
2868Void_t* pvALLOc(size_t bytes)
2869#else
2870Void_t* pvALLOc(bytes) size_t bytes;
2871#endif
2872{
2873 size_t pagesize = malloc_getpagesize;
2874 return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
2875}
2876
2877/*
2878
2879 calloc calls malloc, then zeroes out the allocated chunk.
2880
2881*/
2882
2883#if __STD_C
2884Void_t* cALLOc(size_t n, size_t elem_size)
2885#else
2886Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
2887#endif
2888{
2889 mchunkptr p;
2890 INTERNAL_SIZE_T csz;
2891
2892 INTERNAL_SIZE_T sz = n * elem_size;
2893
2894
2895 /* check if expand_top called, in which case don't need to clear */
2896#if MORECORE_CLEARS
2897 mchunkptr oldtop = top;
2898 INTERNAL_SIZE_T oldtopsize = chunksize(top);
2899#endif
2900 Void_t* mem = mALLOc (sz);
2901
2902 if ((long)n < 0) return 0;
2903
2904 if (mem == 0)
2905 return 0;
2906 else
2907 {
2908 p = mem2chunk(mem);
2909
2910 /* Two optional cases in which clearing not necessary */
2911
2912
2913#if HAVE_MMAP
2914 if (chunk_is_mmapped(p)) return mem;
2915#endif
2916
2917 csz = chunksize(p);
2918
2919#if MORECORE_CLEARS
2920 if (p == oldtop && csz > oldtopsize)
2921 {
2922 /* clear only the bytes from non-freshly-sbrked memory */
2923 csz = oldtopsize;
2924 }
2925#endif
2926
2927 MALLOC_ZERO(mem, csz - SIZE_SZ);
2928 return mem;
2929 }
2930}
2931
2932/*
2933
2934 cfree just calls free. It is needed/defined on some systems
2935 that pair it with calloc, presumably for odd historical reasons.
2936
2937*/
2938
2939#if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__)
2940#if __STD_C
2941void cfree(Void_t *mem)
2942#else
2943void cfree(mem) Void_t *mem;
2944#endif
2945{
2946 fREe(mem);
2947}
2948#endif
2949
2950
2951
2952/*
2953
2954 Malloc_trim gives memory back to the system (via negative
2955 arguments to sbrk) if there is unused memory at the `high' end of
2956 the malloc pool. You can call this after freeing large blocks of
2957 memory to potentially reduce the system-level memory requirements
2958 of a program. However, it cannot guarantee to reduce memory. Under
2959 some allocation patterns, some large free blocks of memory will be
2960 locked between two used chunks, so they cannot be given back to
2961 the system.
2962
2963 The `pad' argument to malloc_trim represents the amount of free
2964 trailing space to leave untrimmed. If this argument is zero,
2965 only the minimum amount of memory to maintain internal data
2966 structures will be left (one page or less). Non-zero arguments
2967 can be supplied to maintain enough trailing space to service
2968 future expected allocations without having to re-obtain memory
2969 from the system.
2970
2971 Malloc_trim returns 1 if it actually released any memory, else 0.
2972
2973*/
2974
2975#if __STD_C
2976int malloc_trim(size_t pad)
2977#else
2978int malloc_trim(pad) size_t pad;
2979#endif
2980{
2981 long top_size; /* Amount of top-most memory */
2982 long extra; /* Amount to release */
2983 char* current_brk; /* address returned by pre-check sbrk call */
2984 char* new_brk; /* address returned by negative sbrk call */
2985
2986 unsigned long pagesz = malloc_getpagesize;
2987
2988 top_size = chunksize(top);
2989 extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
2990
2991 if (extra < (long)pagesz) /* Not enough memory to release */
2992 return 0;
2993
2994 else
2995 {
2996 /* Test to make sure no one else called sbrk */
2997 current_brk = (char*)(MORECORE (0));
2998 if (current_brk != (char*)(top) + top_size)
2999 return 0; /* Apparently we don't own memory; must fail */
3000
3001 else
3002 {
3003 new_brk = (char*)(MORECORE (-extra));
3004
3005 if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */
3006 {
wdenk8bde7f72003-06-27 21:31:46 +00003007 /* Try to figure out what we have */
3008 current_brk = (char*)(MORECORE (0));
3009 top_size = current_brk - (char*)top;
3010 if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
3011 {
3012 sbrked_mem = current_brk - sbrk_base;
3013 set_head(top, top_size | PREV_INUSE);
3014 }
3015 check_chunk(top);
3016 return 0;
wdenk217c9da2002-10-25 20:35:49 +00003017 }
3018
3019 else
3020 {
wdenk8bde7f72003-06-27 21:31:46 +00003021 /* Success. Adjust top accordingly. */
3022 set_head(top, (top_size - extra) | PREV_INUSE);
3023 sbrked_mem -= extra;
3024 check_chunk(top);
3025 return 1;
wdenk217c9da2002-10-25 20:35:49 +00003026 }
3027 }
3028 }
3029}
3030
3031
3032
3033/*
3034 malloc_usable_size:
3035
3036 This routine tells you how many bytes you can actually use in an
3037 allocated chunk, which may be more than you requested (although
3038 often not). You can use this many bytes without worrying about
3039 overwriting other allocated objects. Not a particularly great
3040 programming practice, but still sometimes useful.
3041
3042*/
3043
3044#if __STD_C
3045size_t malloc_usable_size(Void_t* mem)
3046#else
3047size_t malloc_usable_size(mem) Void_t* mem;
3048#endif
3049{
3050 mchunkptr p;
3051 if (mem == 0)
3052 return 0;
3053 else
3054 {
3055 p = mem2chunk(mem);
3056 if(!chunk_is_mmapped(p))
3057 {
3058 if (!inuse(p)) return 0;
3059 check_inuse_chunk(p);
3060 return chunksize(p) - SIZE_SZ;
3061 }
3062 return chunksize(p) - 2*SIZE_SZ;
3063 }
3064}
3065
3066
3067
3068
3069/* Utility to update current_mallinfo for malloc_stats and mallinfo() */
3070
3071#if 0
3072static void malloc_update_mallinfo()
3073{
3074 int i;
3075 mbinptr b;
3076 mchunkptr p;
3077#ifdef DEBUG
3078 mchunkptr q;
3079#endif
3080
3081 INTERNAL_SIZE_T avail = chunksize(top);
3082 int navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;
3083
3084 for (i = 1; i < NAV; ++i)
3085 {
3086 b = bin_at(i);
3087 for (p = last(b); p != b; p = p->bk)
3088 {
3089#ifdef DEBUG
3090 check_free_chunk(p);
3091 for (q = next_chunk(p);
wdenk8bde7f72003-06-27 21:31:46 +00003092 q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
3093 q = next_chunk(q))
3094 check_inuse_chunk(q);
wdenk217c9da2002-10-25 20:35:49 +00003095#endif
3096 avail += chunksize(p);
3097 navail++;
3098 }
3099 }
3100
3101 current_mallinfo.ordblks = navail;
3102 current_mallinfo.uordblks = sbrked_mem - avail;
3103 current_mallinfo.fordblks = avail;
3104 current_mallinfo.hblks = n_mmaps;
3105 current_mallinfo.hblkhd = mmapped_mem;
3106 current_mallinfo.keepcost = chunksize(top);
3107
3108}
3109#endif /* 0 */
3110
3111
3112
3113/*
3114
3115 malloc_stats:
3116
3117 Prints on the amount of space obtain from the system (both
3118 via sbrk and mmap), the maximum amount (which may be more than
3119 current if malloc_trim and/or munmap got called), the maximum
3120 number of simultaneous mmap regions used, and the current number
3121 of bytes allocated via malloc (or realloc, etc) but not yet
3122 freed. (Note that this is the number of bytes allocated, not the
3123 number requested. It will be larger than the number requested
3124 because of alignment and bookkeeping overhead.)
3125
3126*/
3127
3128#if 0
3129void malloc_stats()
3130{
3131 malloc_update_mallinfo();
3132 printf("max system bytes = %10u\n",
wdenk8bde7f72003-06-27 21:31:46 +00003133 (unsigned int)(max_total_mem));
wdenk217c9da2002-10-25 20:35:49 +00003134 printf("system bytes = %10u\n",
wdenk8bde7f72003-06-27 21:31:46 +00003135 (unsigned int)(sbrked_mem + mmapped_mem));
wdenk217c9da2002-10-25 20:35:49 +00003136 printf("in use bytes = %10u\n",
wdenk8bde7f72003-06-27 21:31:46 +00003137 (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
wdenk217c9da2002-10-25 20:35:49 +00003138#if HAVE_MMAP
3139 printf("max mmap regions = %10u\n",
wdenk8bde7f72003-06-27 21:31:46 +00003140 (unsigned int)max_n_mmaps);
wdenk217c9da2002-10-25 20:35:49 +00003141#endif
3142}
3143#endif /* 0 */
3144
3145/*
3146 mallinfo returns a copy of updated current mallinfo.
3147*/
3148
3149#if 0
3150struct mallinfo mALLINFo()
3151{
3152 malloc_update_mallinfo();
3153 return current_mallinfo;
3154}
3155#endif /* 0 */
3156
3157
3158
3159
3160/*
3161 mallopt:
3162
3163 mallopt is the general SVID/XPG interface to tunable parameters.
3164 The format is to provide a (parameter-number, parameter-value) pair.
3165 mallopt then sets the corresponding parameter to the argument
3166 value if it can (i.e., so long as the value is meaningful),
3167 and returns 1 if successful else 0.
3168
3169 See descriptions of tunable parameters above.
3170
3171*/
3172
3173#if __STD_C
3174int mALLOPt(int param_number, int value)
3175#else
3176int mALLOPt(param_number, value) int param_number; int value;
3177#endif
3178{
3179 switch(param_number)
3180 {
3181 case M_TRIM_THRESHOLD:
3182 trim_threshold = value; return 1;
3183 case M_TOP_PAD:
3184 top_pad = value; return 1;
3185 case M_MMAP_THRESHOLD:
3186 mmap_threshold = value; return 1;
3187 case M_MMAP_MAX:
3188#if HAVE_MMAP
3189 n_mmaps_max = value; return 1;
3190#else
3191 if (value != 0) return 0; else n_mmaps_max = value; return 1;
3192#endif
3193
3194 default:
3195 return 0;
3196 }
3197}
3198
3199/*
3200
3201History:
3202
3203 V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
3204 * return null for negative arguments
3205 * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com>
wdenk8bde7f72003-06-27 21:31:46 +00003206 * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
3207 (e.g. WIN32 platforms)
3208 * Cleanup up header file inclusion for WIN32 platforms
3209 * Cleanup code to avoid Microsoft Visual C++ compiler complaints
3210 * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
3211 memory allocation routines
3212 * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
3213 * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
wdenk217c9da2002-10-25 20:35:49 +00003214 usage of 'assert' in non-WIN32 code
wdenk8bde7f72003-06-27 21:31:46 +00003215 * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
3216 avoid infinite loop
wdenk217c9da2002-10-25 20:35:49 +00003217 * Always call 'fREe()' rather than 'free()'
3218
3219 V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
3220 * Fixed ordering problem with boundary-stamping
3221
3222 V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee)
3223 * Added pvalloc, as recommended by H.J. Liu
3224 * Added 64bit pointer support mainly from Wolfram Gloger
3225 * Added anonymously donated WIN32 sbrk emulation
3226 * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
3227 * malloc_extend_top: fix mask error that caused wastage after
wdenk8bde7f72003-06-27 21:31:46 +00003228 foreign sbrks
wdenk217c9da2002-10-25 20:35:49 +00003229 * Add linux mremap support code from HJ Liu
3230
3231 V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee)
3232 * Integrated most documentation with the code.
3233 * Add support for mmap, with help from
wdenk8bde7f72003-06-27 21:31:46 +00003234 Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
wdenk217c9da2002-10-25 20:35:49 +00003235 * Use last_remainder in more cases.
3236 * Pack bins using idea from colin@nyx10.cs.du.edu
3237 * Use ordered bins instead of best-fit threshhold
3238 * Eliminate block-local decls to simplify tracing and debugging.
3239 * Support another case of realloc via move into top
3240 * Fix error occuring when initial sbrk_base not word-aligned.
3241 * Rely on page size for units instead of SBRK_UNIT to
wdenk8bde7f72003-06-27 21:31:46 +00003242 avoid surprises about sbrk alignment conventions.
wdenk217c9da2002-10-25 20:35:49 +00003243 * Add mallinfo, mallopt. Thanks to Raymond Nijssen
wdenk8bde7f72003-06-27 21:31:46 +00003244 (raymond@es.ele.tue.nl) for the suggestion.
wdenk217c9da2002-10-25 20:35:49 +00003245 * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
3246 * More precautions for cases where other routines call sbrk,
wdenk8bde7f72003-06-27 21:31:46 +00003247 courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
wdenk217c9da2002-10-25 20:35:49 +00003248 * Added macros etc., allowing use in linux libc from
wdenk8bde7f72003-06-27 21:31:46 +00003249 H.J. Lu (hjl@gnu.ai.mit.edu)
wdenk217c9da2002-10-25 20:35:49 +00003250 * Inverted this history list
3251
3252 V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee)
3253 * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
3254 * Removed all preallocation code since under current scheme
wdenk8bde7f72003-06-27 21:31:46 +00003255 the work required to undo bad preallocations exceeds
3256 the work saved in good cases for most test programs.
wdenk217c9da2002-10-25 20:35:49 +00003257 * No longer use return list or unconsolidated bins since
wdenk8bde7f72003-06-27 21:31:46 +00003258 no scheme using them consistently outperforms those that don't
3259 given above changes.
wdenk217c9da2002-10-25 20:35:49 +00003260 * Use best fit for very large chunks to prevent some worst-cases.
3261 * Added some support for debugging
3262
3263 V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee)
3264 * Removed footers when chunks are in use. Thanks to
wdenk8bde7f72003-06-27 21:31:46 +00003265 Paul Wilson (wilson@cs.texas.edu) for the suggestion.
wdenk217c9da2002-10-25 20:35:49 +00003266
3267 V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee)
3268 * Added malloc_trim, with help from Wolfram Gloger
wdenk8bde7f72003-06-27 21:31:46 +00003269 (wmglo@Dent.MED.Uni-Muenchen.DE).
wdenk217c9da2002-10-25 20:35:49 +00003270
3271 V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g)
3272
3273 V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g)
3274 * realloc: try to expand in both directions
3275 * malloc: swap order of clean-bin strategy;
3276 * realloc: only conditionally expand backwards
3277 * Try not to scavenge used bins
3278 * Use bin counts as a guide to preallocation
3279 * Occasionally bin return list chunks in first scan
3280 * Add a few optimizations from colin@nyx10.cs.du.edu
3281
3282 V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g)
3283 * faster bin computation & slightly different binning
3284 * merged all consolidations to one part of malloc proper
wdenk8bde7f72003-06-27 21:31:46 +00003285 (eliminating old malloc_find_space & malloc_clean_bin)
wdenk217c9da2002-10-25 20:35:49 +00003286 * Scan 2 returns chunks (not just 1)
3287 * Propagate failure in realloc if malloc returns 0
3288 * Add stuff to allow compilation on non-ANSI compilers
wdenk8bde7f72003-06-27 21:31:46 +00003289 from kpv@research.att.com
wdenk217c9da2002-10-25 20:35:49 +00003290
3291 V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu)
3292 * removed potential for odd address access in prev_chunk
3293 * removed dependency on getpagesize.h
3294 * misc cosmetics and a bit more internal documentation
3295 * anticosmetics: mangled names in macros to evade debugger strangeness
3296 * tested on sparc, hp-700, dec-mips, rs6000
wdenk8bde7f72003-06-27 21:31:46 +00003297 with gcc & native cc (hp, dec only) allowing
3298 Detlefs & Zorn comparison study (in SIGPLAN Notices.)
wdenk217c9da2002-10-25 20:35:49 +00003299
3300 Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu)
3301 * Based loosely on libg++-1.2X malloc. (It retains some of the overall
wdenk8bde7f72003-06-27 21:31:46 +00003302 structure of old version, but most details differ.)
wdenk217c9da2002-10-25 20:35:49 +00003303
3304*/