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+/*
+ This is a version (aka dlmalloc) of malloc/free/realloc written by
+ Doug Lea and released to the public domain, as explained at
+ http://creativecommons.org/publicdomain/zero/1.0/ Send questions,
+ comments, complaints, performance data, etc to dl@cs.oswego.edu
+
+* Version 2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea
+ Note: There may be an updated version of this malloc obtainable at
+ ftp://gee.cs.oswego.edu/pub/misc/malloc.c
+ Check before installing!
+
+* Quickstart
+
+ This library is all in one file to simplify the most common usage:
+ ftp it, compile it (-O3), and link it into another program. All of
+ the compile-time options default to reasonable values for use on
+ most platforms. You might later want to step through various
+ compile-time and dynamic tuning options.
+
+ For convenience, an include file for code using this malloc is at:
+ ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.6.h
+ You don't really need this .h file unless you call functions not
+ defined in your system include files. The .h file contains only the
+ excerpts from this file needed for using this malloc on ANSI C/C++
+ systems, so long as you haven't changed compile-time options about
+ naming and tuning parameters. If you do, then you can create your
+ own malloc.h that does include all settings by cutting at the point
+ indicated below. Note that you may already by default be using a C
+ library containing a malloc that is based on some version of this
+ malloc (for example in linux). You might still want to use the one
+ in this file to customize settings or to avoid overheads associated
+ with library versions.
+
+* Vital statistics:
+
+ Supported pointer/size_t representation: 4 or 8 bytes
+ size_t MUST be an unsigned type of the same width as
+ pointers. (If you are using an ancient system that declares
+ size_t as a signed type, or need it to be a different width
+ than pointers, you can use a previous release of this malloc
+ (e.g. 2.7.2) supporting these.)
+
+ Alignment: 8 bytes (minimum)
+ This suffices for nearly all current machines and C compilers.
+ However, you can define MALLOC_ALIGNMENT to be wider than this
+ if necessary (up to 128bytes), at the expense of using more space.
+
+ Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes)
+ 8 or 16 bytes (if 8byte sizes)
+ Each malloced chunk has a hidden word of overhead holding size
+ and status information, and additional cross-check word
+ if FOOTERS is defined.
+
+ Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead)
+ 8-byte ptrs: 32 bytes (including overhead)
+
+ Even a request for zero bytes (i.e., malloc(0)) returns a
+ pointer to something of the minimum allocatable size.
+ The maximum overhead wastage (i.e., number of extra bytes
+ allocated than were requested in malloc) is less than or equal
+ to the minimum size, except for requests >= mmap_threshold that
+ are serviced via mmap(), where the worst case wastage is about
+ 32 bytes plus the remainder from a system page (the minimal
+ mmap unit); typically 4096 or 8192 bytes.
+
+ Security: static-safe; optionally more or less
+ The "security" of malloc refers to the ability of malicious
+ code to accentuate the effects of errors (for example, freeing
+ space that is not currently malloc'ed or overwriting past the
+ ends of chunks) in code that calls malloc. This malloc
+ guarantees not to modify any memory locations below the base of
+ heap, i.e., static variables, even in the presence of usage
+ errors. The routines additionally detect most improper frees
+ and reallocs. All this holds as long as the static bookkeeping
+ for malloc itself is not corrupted by some other means. This
+ is only one aspect of security -- these checks do not, and
+ cannot, detect all possible programming errors.
+
+ If FOOTERS is defined nonzero, then each allocated chunk
+ carries an additional check word to verify that it was malloced
+ from its space. These check words are the same within each
+ execution of a program using malloc, but differ across
+ executions, so externally crafted fake chunks cannot be
+ freed. This improves security by rejecting frees/reallocs that
+ could corrupt heap memory, in addition to the checks preventing
+ writes to statics that are always on. This may further improve
+ security at the expense of time and space overhead. (Note that
+ FOOTERS may also be worth using with MSPACES.)
+
+ By default detected errors cause the program to abort (calling
+ "abort()"). You can override this to instead proceed past
+ errors by defining PROCEED_ON_ERROR. In this case, a bad free
+ has no effect, and a malloc that encounters a bad address
+ caused by user overwrites will ignore the bad address by
+ dropping pointers and indices to all known memory. This may
+ be appropriate for programs that should continue if at all
+ possible in the face of programming errors, although they may
+ run out of memory because dropped memory is never reclaimed.
+
+ If you don't like either of these options, you can define
+ CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
+ else. And if if you are sure that your program using malloc has
+ no errors or vulnerabilities, you can define INSECURE to 1,
+ which might (or might not) provide a small performance improvement.
+
+ It is also possible to limit the maximum total allocatable
+ space, using malloc_set_footprint_limit. This is not
+ designed as a security feature in itself (calls to set limits
+ are not screened or privileged), but may be useful as one
+ aspect of a secure implementation.
+
+ Thread-safety: NOT thread-safe unless USE_LOCKS defined non-zero
+ When USE_LOCKS is defined, each public call to malloc, free,
+ etc is surrounded with a lock. By default, this uses a plain
+ pthread mutex, win32 critical section, or a spin-lock if if
+ available for the platform and not disabled by setting
+ USE_SPIN_LOCKS=0. However, if USE_RECURSIVE_LOCKS is defined,
+ recursive versions are used instead (which are not required for
+ base functionality but may be needed in layered extensions).
+ Using a global lock is not especially fast, and can be a major
+ bottleneck. It is designed only to provide minimal protection
+ in concurrent environments, and to provide a basis for
+ extensions. If you are using malloc in a concurrent program,
+ consider instead using nedmalloc
+ (http://www.nedprod.com/programs/portable/nedmalloc/) or
+ ptmalloc (See http://www.malloc.de), which are derived from
+ versions of this malloc.
+
+ System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
+ This malloc can use unix sbrk or any emulation (invoked using
+ the CALL_MORECORE macro) and/or mmap/munmap or any emulation
+ (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
+ memory. On most unix systems, it tends to work best if both
+ MORECORE and MMAP are enabled. On Win32, it uses emulations
+ based on VirtualAlloc. It also uses common C library functions
+ like memset.
+
+ Compliance: I believe it is compliant with the Single Unix Specification
+ (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
+ others as well.
+
+* Overview of algorithms
+
+ This is not the fastest, most space-conserving, most portable, or
+ most tunable malloc ever written. However it is among the fastest
+ while also being among the most space-conserving, portable and
+ tunable. Consistent balance across these factors results in a good
+ general-purpose allocator for malloc-intensive programs.
+
+ In most ways, this malloc is a best-fit allocator. Generally, it
+ chooses the best-fitting existing chunk for a request, with ties
+ broken in approximately least-recently-used order. (This strategy
+ normally maintains low fragmentation.) However, for requests less
+ than 256bytes, it deviates from best-fit when there is not an
+ exactly fitting available chunk by preferring to use space adjacent
+ to that used for the previous small request, as well as by breaking
+ ties in approximately most-recently-used order. (These enhance
+ locality of series of small allocations.) And for very large requests
+ (>= 256Kb by default), it relies on system memory mapping
+ facilities, if supported. (This helps avoid carrying around and
+ possibly fragmenting memory used only for large chunks.)
+
+ All operations (except malloc_stats and mallinfo) have execution
+ times that are bounded by a constant factor of the number of bits in
+ a size_t, not counting any clearing in calloc or copying in realloc,
+ or actions surrounding MORECORE and MMAP that have times
+ proportional to the number of non-contiguous regions returned by
+ system allocation routines, which is often just 1. In real-time
+ applications, you can optionally suppress segment traversals using
+ NO_SEGMENT_TRAVERSAL, which assures bounded execution even when
+ system allocators return non-contiguous spaces, at the typical
+ expense of carrying around more memory and increased fragmentation.
+
+ The implementation is not very modular and seriously overuses
+ macros. Perhaps someday all C compilers will do as good a job
+ inlining modular code as can now be done by brute-force expansion,
+ but now, enough of them seem not to.
+
+ Some compilers issue a lot of warnings about code that is
+ dead/unreachable only on some platforms, and also about intentional
+ uses of negation on unsigned types. All known cases of each can be
+ ignored.
+
+ For a longer but out of date high-level description, see
+ http://gee.cs.oswego.edu/dl/html/malloc.html
+
+* MSPACES
+ If MSPACES is defined, then in addition to malloc, free, etc.,
+ this file also defines mspace_malloc, mspace_free, etc. These
+ are versions of malloc routines that take an "mspace" argument
+ obtained using create_mspace, to control all internal bookkeeping.
+ If ONLY_MSPACES is defined, only these versions are compiled.
+ So if you would like to use this allocator for only some allocations,
+ and your system malloc for others, you can compile with
+ ONLY_MSPACES and then do something like...
+ static mspace mymspace = create_mspace(0,0); // for example
+ #define mymalloc(bytes) mspace_malloc(mymspace, bytes)
+
+ (Note: If you only need one instance of an mspace, you can instead
+ use "USE_DL_PREFIX" to relabel the global malloc.)
+
+ You can similarly create thread-local allocators by storing
+ mspaces as thread-locals. For example:
+ static __thread mspace tlms = 0;
+ void* tlmalloc(size_t bytes) {
+ if (tlms == 0) tlms = create_mspace(0, 0);
+ return mspace_malloc(tlms, bytes);
+ }
+ void tlfree(void* mem) { mspace_free(tlms, mem); }
+
+ Unless FOOTERS is defined, each mspace is completely independent.
+ You cannot allocate from one and free to another (although
+ conformance is only weakly checked, so usage errors are not always
+ caught). If FOOTERS is defined, then each chunk carries around a tag
+ indicating its originating mspace, and frees are directed to their
+ originating spaces. Normally, this requires use of locks.
+
+ ------------------------- Compile-time options ---------------------------
+
+Be careful in setting #define values for numerical constants of type
+size_t. On some systems, literal values are not automatically extended
+to size_t precision unless they are explicitly casted. You can also
+use the symbolic values MAX_SIZE_T, SIZE_T_ONE, etc below.
+
+WIN32 default: defined if _WIN32 defined
+ Defining WIN32 sets up defaults for MS environment and compilers.
+ Otherwise defaults are for unix. Beware that there seem to be some
+ cases where this malloc might not be a pure drop-in replacement for
+ Win32 malloc: Random-looking failures from Win32 GDI API's (eg;
+ SetDIBits()) may be due to bugs in some video driver implementations
+ when pixel buffers are malloc()ed, and the region spans more than
+ one VirtualAlloc()ed region. Because dlmalloc uses a small (64Kb)
+ default granularity, pixel buffers may straddle virtual allocation
+ regions more often than when using the Microsoft allocator. You can
+ avoid this by using VirtualAlloc() and VirtualFree() for all pixel
+ buffers rather than using malloc(). If this is not possible,
+ recompile this malloc with a larger DEFAULT_GRANULARITY. Note:
+ in cases where MSC and gcc (cygwin) are known to differ on WIN32,
+ conditions use _MSC_VER to distinguish them.
+
+DLMALLOC_EXPORT default: extern
+ Defines how public APIs are declared. If you want to export via a
+ Windows DLL, you might define this as
+ #define DLMALLOC_EXPORT extern __declspec(dllexport)
+ If you want a POSIX ELF shared object, you might use
+ #define DLMALLOC_EXPORT extern __attribute__((visibility("default")))
+
+MALLOC_ALIGNMENT default: (size_t)(2 * sizeof(void *))
+ Controls the minimum alignment for malloc'ed chunks. It must be a
+ power of two and at least 8, even on machines for which smaller
+ alignments would suffice. It may be defined as larger than this
+ though. Note however that code and data structures are optimized for
+ the case of 8-byte alignment.
+
+MSPACES default: 0 (false)
+ If true, compile in support for independent allocation spaces.
+ This is only supported if HAVE_MMAP is true.
+
+ONLY_MSPACES default: 0 (false)
+ If true, only compile in mspace versions, not regular versions.
+
+USE_LOCKS default: 0 (false)
+ Causes each call to each public routine to be surrounded with
+ pthread or WIN32 mutex lock/unlock. (If set true, this can be
+ overridden on a per-mspace basis for mspace versions.) If set to a
+ non-zero value other than 1, locks are used, but their
+ implementation is left out, so lock functions must be supplied manually,
+ as described below.
+
+USE_SPIN_LOCKS default: 1 iff USE_LOCKS and spin locks available
+ If true, uses custom spin locks for locking. This is currently
+ supported only gcc >= 4.1, older gccs on x86 platforms, and recent
+ MS compilers. Otherwise, posix locks or win32 critical sections are
+ used.
+
+USE_RECURSIVE_LOCKS default: not defined
+ If defined nonzero, uses recursive (aka reentrant) locks, otherwise
+ uses plain mutexes. This is not required for malloc proper, but may
+ be needed for layered allocators such as nedmalloc.
+
+LOCK_AT_FORK default: not defined
+ If defined nonzero, performs pthread_atfork upon initialization
+ to initialize child lock while holding parent lock. The implementation
+ assumes that pthread locks (not custom locks) are being used. In other
+ cases, you may need to customize the implementation.
+
+FOOTERS default: 0
+ If true, provide extra checking and dispatching by placing
+ information in the footers of allocated chunks. This adds
+ space and time overhead.
+
+INSECURE default: 0
+ If true, omit checks for usage errors and heap space overwrites.
+
+USE_DL_PREFIX default: NOT defined
+ Causes compiler to prefix all public routines with the string 'dl'.
+ This can be useful when you only want to use this malloc in one part
+ of a program, using your regular system malloc elsewhere.
+
+MALLOC_INSPECT_ALL default: NOT defined
+ If defined, compiles malloc_inspect_all and mspace_inspect_all, that
+ perform traversal of all heap space. Unless access to these
+ functions is otherwise restricted, you probably do not want to
+ include them in secure implementations.
+
+DLM_ABORT default: defined as abort()
+ Defines how to abort on failed checks. On most systems, a failed
+ check cannot die with an "assert" or even print an informative
+ message, because the underlying print routines in turn call malloc,
+ which will fail again. Generally, the best policy is to simply call
+ abort(). It's not very useful to do more than this because many
+ errors due to overwriting will show up as address faults (null, odd
+ addresses etc) rather than malloc-triggered checks, so will also
+ abort. Also, most compilers know that abort() does not return, so
+ can better optimize code conditionally calling it.
+
+PROCEED_ON_ERROR default: defined as 0 (false)
+ Controls whether detected bad addresses cause them to bypassed
+ rather than aborting. If set, detected bad arguments to free and
+ realloc are ignored. And all bookkeeping information is zeroed out
+ upon a detected overwrite of freed heap space, thus losing the
+ ability to ever return it from malloc again, but enabling the
+ application to proceed. If PROCEED_ON_ERROR is defined, the
+ static variable malloc_corruption_error_count is compiled in
+ and can be examined to see if errors have occurred. This option
+ generates slower code than the default abort policy.
+
+DEBUG default: NOT defined
+ The DEBUG setting is mainly intended for people trying to modify
+ this code or diagnose problems when porting to new platforms.
+ However, it may also be able to better isolate user errors than just
+ using runtime checks. The assertions in the check routines spell
+ out in more detail the assumptions and invariants underlying the
+ algorithms. The checking is fairly extensive, and will slow down
+ execution noticeably. Calling malloc_stats or mallinfo with DEBUG
+ set will attempt to check every non-mmapped allocated and free chunk
+ in the course of computing the summaries.
+
+DLM_ABORT_ON_ASSERT_FAILURE default: defined as 1 (true)
+ Debugging assertion failures can be nearly impossible if your
+ version of the assert macro causes malloc to be called, which will
+ lead to a cascade of further failures, blowing the runtime stack.
+ DLM_ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
+ which will usually make debugging easier.
+
+MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32
+ The action to take before "return 0" when malloc fails to be able to
+ return memory because there is none available.
+
+HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES
+ True if this system supports sbrk or an emulation of it.
+
+MORECORE default: sbrk
+ The name of the sbrk-style system routine to call to obtain more
+ memory. See below for guidance on writing custom MORECORE
+ functions. The type of the argument to sbrk/MORECORE varies across
+ systems. It cannot be size_t, because it supports negative
+ arguments, so it is normally the signed type of the same width as
+ size_t (sometimes declared as "intptr_t"). It doesn't much matter
+ though. Internally, we only call it with arguments less than half
+ the max value of a size_t, which should work across all reasonable
+ possibilities, although sometimes generating compiler warnings.
+
+MORECORE_CONTIGUOUS default: 1 (true) if HAVE_MORECORE
+ If true, take advantage of fact that consecutive calls to MORECORE
+ with positive arguments always return contiguous increasing
+ addresses. This is true of unix sbrk. It does not hurt too much to
+ set it true anyway, since malloc copes with non-contiguities.
+ Setting it false when definitely non-contiguous saves time
+ and possibly wasted space it would take to discover this though.
+
+MORECORE_CANNOT_TRIM default: NOT defined
+ True if MORECORE cannot release space back to the system when given
+ negative arguments. This is generally necessary only if you are
+ using a hand-crafted MORECORE function that cannot handle negative
+ arguments.
+
+NO_SEGMENT_TRAVERSAL default: 0
+ If non-zero, suppresses traversals of memory segments
+ returned by either MORECORE or CALL_MMAP. This disables
+ merging of segments that are contiguous, and selectively
+ releasing them to the OS if unused, but bounds execution times.
+
+HAVE_MMAP default: 1 (true)
+ True if this system supports mmap or an emulation of it. If so, and
+ HAVE_MORECORE is not true, MMAP is used for all system
+ allocation. If set and HAVE_MORECORE is true as well, MMAP is
+ primarily used to directly allocate very large blocks. It is also
+ used as a backup strategy in cases where MORECORE fails to provide
+ space from system. Note: A single call to MUNMAP is assumed to be
+ able to unmap memory that may have be allocated using multiple calls
+ to MMAP, so long as they are adjacent.
+
+HAVE_MREMAP default: 1 on linux, else 0
+ If true realloc() uses mremap() to re-allocate large blocks and
+ extend or shrink allocation spaces.
+
+MMAP_CLEARS default: 1 except on WINCE.
+ True if mmap clears memory so calloc doesn't need to. This is true
+ for standard unix mmap using /dev/zero and on WIN32 except for WINCE.
+
+USE_BUILTIN_FFS default: 0 (i.e., not used)
+ Causes malloc to use the builtin ffs() function to compute indices.
+ Some compilers may recognize and intrinsify ffs to be faster than the
+ supplied C version. Also, the case of x86 using gcc is special-cased
+ to an asm instruction, so is already as fast as it can be, and so
+ this setting has no effect. Similarly for Win32 under recent MS compilers.
+ (On most x86s, the asm version is only slightly faster than the C version.)
+
+malloc_getpagesize default: derive from system includes, or 4096.
+ The system page size. To the extent possible, this malloc manages
+ memory from the system in page-size units. This may be (and
+ usually is) a function rather than a constant. This is ignored
+ if WIN32, where page size is determined using getSystemInfo during
+ initialization.
+
+USE_DEV_RANDOM default: 0 (i.e., not used)
+ Causes malloc to use /dev/random to initialize secure magic seed for
+ stamping footers. Otherwise, the current time is used.
+
+NO_MALLINFO default: 0
+ If defined, don't compile "mallinfo". This can be a simple way
+ of dealing with mismatches between system declarations and
+ those in this file.
+
+MALLINFO_FIELD_TYPE default: size_t
+ The type of the fields in the mallinfo struct. This was originally
+ defined as "int" in SVID etc, but is more usefully defined as
+ size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set
+
+NO_MALLOC_STATS default: 0
+ If defined, don't compile "malloc_stats". This avoids calls to
+ fprintf and bringing in stdio dependencies you might not want.
+
+REALLOC_ZERO_BYTES_FREES default: not defined
+ This should be set if a call to realloc with zero bytes should
+ be the same as a call to free. Some people think it should. Otherwise,
+ since this malloc returns a unique pointer for malloc(0), so does
+ realloc(p, 0).
+
+LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
+LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H
+LACKS_STDLIB_H LACKS_SCHED_H LACKS_TIME_H default: NOT defined unless on WIN32
+ Define these if your system does not have these header files.
+ You might need to manually insert some of the declarations they provide.
+
+DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS,
+ system_info.dwAllocationGranularity in WIN32,
+ otherwise 64K.
+ Also settable using mallopt(M_GRANULARITY, x)
+ The unit for allocating and deallocating memory from the system. On
+ most systems with contiguous MORECORE, there is no reason to
+ make this more than a page. However, systems with MMAP tend to
+ either require or encourage larger granularities. You can increase
+ this value to prevent system allocation functions to be called so
+ often, especially if they are slow. The value must be at least one
+ page and must be a power of two. Setting to 0 causes initialization
+ to either page size or win32 region size. (Note: In previous
+ versions of malloc, the equivalent of this option was called
+ "TOP_PAD")
+
+DEFAULT_TRIM_THRESHOLD default: 2MB
+ Also settable using mallopt(M_TRIM_THRESHOLD, x)
+ The maximum amount of unused top-most memory to keep before
+ releasing via malloc_trim in free(). Automatic trimming is mainly
+ useful in long-lived programs using contiguous MORECORE. Because
+ trimming via sbrk can be slow on some systems, and can sometimes be
+ wasteful (in cases where programs immediately afterward allocate
+ more large chunks) the value should be high enough so that your
+ overall system performance would improve by releasing this much
+ memory. As a rough guide, you might set to a value close to the
+ average size of a process (program) running on your system.
+ Releasing this much memory would allow such a process to run in
+ memory. Generally, it is worth tuning trim thresholds when a
+ program undergoes phases where several large chunks are allocated
+ and released in ways that can reuse each other's storage, perhaps
+ mixed with phases where there are no such chunks at all. The trim
+ value must be greater than page size to have any useful effect. To
+ disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
+ some people use of mallocing a huge space and then freeing it at
+ program startup, in an attempt to reserve system memory, doesn't
+ have the intended effect under automatic trimming, since that memory
+ will immediately be returned to the system.
+
+DEFAULT_MMAP_THRESHOLD default: 256K
+ Also settable using mallopt(M_MMAP_THRESHOLD, x)
+ The request size threshold for using MMAP to directly service a
+ request. Requests of at least this size that cannot be allocated
+ using already-existing space will be serviced via mmap. (If enough
+ normal freed space already exists it is used instead.) Using mmap
+ segregates relatively large chunks of memory so that they can be
+ individually obtained and released from the host system. A request
+ serviced through mmap is never reused by any other request (at least
+ not directly; the system may just so happen to remap successive
+ requests to the same locations). Segregating space in this way has
+ the benefits that: Mmapped space can always be individually released
+ back to the system, which helps keep the system level memory demands
+ of a long-lived program low. Also, mapped memory doesn't become
+ `locked' between other chunks, as can happen with normally allocated
+ chunks, which means that even trimming via malloc_trim would not
+ release them. However, it has the disadvantage that the space
+ cannot be reclaimed, consolidated, and then used to service later
+ requests, as happens with normal chunks. The advantages of mmap
+ nearly always outweigh disadvantages for "large" chunks, but the
+ value of "large" may vary across systems. The default is an
+ empirically derived value that works well in most systems. You can
+ disable mmap by setting to MAX_SIZE_T.
+
+MAX_RELEASE_CHECK_RATE default: 4095 unless not HAVE_MMAP
+ The number of consolidated frees between checks to release
+ unused segments when freeing. When using non-contiguous segments,
+ especially with multiple mspaces, checking only for topmost space
+ doesn't always suffice to trigger trimming. To compensate for this,
+ free() will, with a period of MAX_RELEASE_CHECK_RATE (or the
+ current number of segments, if greater) try to release unused
+ segments to the OS when freeing chunks that result in
+ consolidation. The best value for this parameter is a compromise
+ between slowing down frees with relatively costly checks that
+ rarely trigger versus holding on to unused memory. To effectively
+ disable, set to MAX_SIZE_T. This may lead to a very slight speed
+ improvement at the expense of carrying around more memory.
+*/
+
+#include <vppinfra/clib.h>
+#include <vppinfra/cache.h>
+
+/* Version identifier to allow people to support multiple versions */
+#ifndef DLMALLOC_VERSION
+#define DLMALLOC_VERSION 20806
+#endif /* DLMALLOC_VERSION */
+
+#ifndef DLMALLOC_EXPORT
+#define DLMALLOC_EXPORT extern
+#endif
+
+#ifndef WIN32
+#ifdef _WIN32
+#define WIN32 1
+#endif /* _WIN32 */
+#ifdef _WIN32_WCE
+#define LACKS_FCNTL_H
+#define WIN32 1
+#endif /* _WIN32_WCE */
+#endif /* WIN32 */
+#ifdef WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <tchar.h>
+#define HAVE_MMAP 1
+#define HAVE_MORECORE 0
+#define LACKS_UNISTD_H
+#define LACKS_SYS_PARAM_H
+#define LACKS_SYS_MMAN_H
+#define LACKS_STRING_H
+#define LACKS_STRINGS_H
+#define LACKS_SYS_TYPES_H
+#define LACKS_ERRNO_H
+#define LACKS_SCHED_H
+#ifndef MALLOC_FAILURE_ACTION
+#define MALLOC_FAILURE_ACTION
+#endif /* MALLOC_FAILURE_ACTION */
+#ifndef MMAP_CLEARS
+#ifdef _WIN32_WCE /* WINCE reportedly does not clear */
+#define MMAP_CLEARS 0
+#else
+#define MMAP_CLEARS 1
+#endif /* _WIN32_WCE */
+#endif /*MMAP_CLEARS */
+#endif /* WIN32 */
+
+#if defined(DARWIN) || defined(_DARWIN)
+/* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
+#ifndef HAVE_MORECORE
+#define HAVE_MORECORE 0
+#define HAVE_MMAP 1
+/* OSX allocators provide 16 byte alignment */
+#ifndef MALLOC_ALIGNMENT
+#define MALLOC_ALIGNMENT ((size_t)16U)
+#endif
+#endif /* HAVE_MORECORE */
+#endif /* DARWIN */
+
+#ifndef LACKS_SYS_TYPES_H
+#include <sys/types.h> /* For size_t */
+#endif /* LACKS_SYS_TYPES_H */
+
+/* The maximum possible size_t value has all bits set */
+#define MAX_SIZE_T (~(size_t)0)
+
+#define USE_LOCKS 1
+
+#ifndef USE_LOCKS /* ensure true if spin or recursive locks set */
+#define USE_LOCKS ((defined(USE_SPIN_LOCKS) && USE_SPIN_LOCKS != 0) || \
+ (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0))
+#endif /* USE_LOCKS */
+
+#if USE_LOCKS /* Spin locks for gcc >= 4.1, older gcc on x86, MSC >= 1310 */
+#if ((defined(__GNUC__) && \
+ ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) || \
+ defined(__i386__) || defined(__x86_64__))) || \
+ (defined(_MSC_VER) && _MSC_VER>=1310))
+#ifndef USE_SPIN_LOCKS
+#define USE_SPIN_LOCKS 1
+#endif /* USE_SPIN_LOCKS */
+#elif USE_SPIN_LOCKS
+#error "USE_SPIN_LOCKS defined without implementation"
+#endif /* ... locks available... */
+#elif !defined(USE_SPIN_LOCKS)
+#define USE_SPIN_LOCKS 0
+#endif /* USE_LOCKS */
+
+#ifndef ONLY_MSPACES
+#define ONLY_MSPACES 1
+#endif /* ONLY_MSPACES */
+#ifndef MSPACES
+#if ONLY_MSPACES
+#define MSPACES 1
+#else /* ONLY_MSPACES */
+#define MSPACES 0
+#endif /* ONLY_MSPACES */
+#endif /* MSPACES */
+#ifndef MALLOC_ALIGNMENT
+#define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *)))
+#endif /* MALLOC_ALIGNMENT */
+#ifndef FOOTERS
+#define FOOTERS 0
+#endif /* FOOTERS */
+#ifndef DLM_ABORT
+#define DLM_ABORT abort()
+#endif /* DLM_ABORT */
+#ifndef DLM_ABORT_ON_ASSERT_FAILURE
+#define DLM_ABORT_ON_ASSERT_FAILURE 1
+#endif /* DLM_ABORT_ON_ASSERT_FAILURE */
+#ifndef PROCEED_ON_ERROR
+#define PROCEED_ON_ERROR 0
+#endif /* PROCEED_ON_ERROR */
+
+#ifndef INSECURE
+#define INSECURE 0
+#endif /* INSECURE */
+#ifndef MALLOC_INSPECT_ALL
+#define MALLOC_INSPECT_ALL 0
+#endif /* MALLOC_INSPECT_ALL */
+#ifndef HAVE_MMAP
+#define HAVE_MMAP 1
+#endif /* HAVE_MMAP */
+#ifndef MMAP_CLEARS
+#define MMAP_CLEARS 1
+#endif /* MMAP_CLEARS */
+#ifndef HAVE_MREMAP
+#ifdef linux
+#define HAVE_MREMAP 1
+#define _GNU_SOURCE /* Turns on mremap() definition */
+#else /* linux */
+#define HAVE_MREMAP 0
+#endif /* linux */
+#endif /* HAVE_MREMAP */
+#ifndef MALLOC_FAILURE_ACTION
+#define MALLOC_FAILURE_ACTION errno = ENOMEM;
+#endif /* MALLOC_FAILURE_ACTION */
+#ifndef HAVE_MORECORE
+#if ONLY_MSPACES
+#define HAVE_MORECORE 0
+#else /* ONLY_MSPACES */
+#define HAVE_MORECORE 1
+#endif /* ONLY_MSPACES */
+#endif /* HAVE_MORECORE */
+#if !HAVE_MORECORE
+#define MORECORE_CONTIGUOUS 0
+#else /* !HAVE_MORECORE */
+#define MORECORE_DEFAULT sbrk
+#ifndef MORECORE_CONTIGUOUS
+#define MORECORE_CONTIGUOUS 1
+#endif /* MORECORE_CONTIGUOUS */
+#endif /* HAVE_MORECORE */
+#ifndef DEFAULT_GRANULARITY
+#if (MORECORE_CONTIGUOUS || defined(WIN32))
+#define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */
+#else /* MORECORE_CONTIGUOUS */
+#define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
+#endif /* MORECORE_CONTIGUOUS */
+#endif /* DEFAULT_GRANULARITY */
+#ifndef DEFAULT_TRIM_THRESHOLD
+#ifndef MORECORE_CANNOT_TRIM
+#define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
+#else /* MORECORE_CANNOT_TRIM */
+#define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
+#endif /* MORECORE_CANNOT_TRIM */
+#endif /* DEFAULT_TRIM_THRESHOLD */
+#ifndef DEFAULT_MMAP_THRESHOLD
+#if HAVE_MMAP
+#define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
+#else /* HAVE_MMAP */
+#define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
+#endif /* HAVE_MMAP */
+#endif /* DEFAULT_MMAP_THRESHOLD */
+#ifndef MAX_RELEASE_CHECK_RATE
+#if HAVE_MMAP
+#define MAX_RELEASE_CHECK_RATE 4095
+#else
+#define MAX_RELEASE_CHECK_RATE MAX_SIZE_T
+#endif /* HAVE_MMAP */
+#endif /* MAX_RELEASE_CHECK_RATE */
+#ifndef USE_BUILTIN_FFS
+#define USE_BUILTIN_FFS 0
+#endif /* USE_BUILTIN_FFS */
+#ifndef USE_DEV_RANDOM
+#define USE_DEV_RANDOM 0
+#endif /* USE_DEV_RANDOM */
+#ifndef NO_MALLINFO
+#define NO_MALLINFO 0
+#endif /* NO_MALLINFO */
+#ifndef MALLINFO_FIELD_TYPE
+#define MALLINFO_FIELD_TYPE size_t
+#endif /* MALLINFO_FIELD_TYPE */
+#ifndef NO_MALLOC_STATS
+#define NO_MALLOC_STATS 0
+#endif /* NO_MALLOC_STATS */
+#ifndef NO_SEGMENT_TRAVERSAL
+#define NO_SEGMENT_TRAVERSAL 0
+#endif /* NO_SEGMENT_TRAVERSAL */
+
+/*
+ mallopt tuning options. SVID/XPG defines four standard parameter
+ numbers for mallopt, normally defined in malloc.h. None of these
+ are used in this malloc, so setting them has no effect. But this
+ malloc does support the following options.
+*/
+
+#define M_TRIM_THRESHOLD (-1)
+#define M_GRANULARITY (-2)
+#define M_MMAP_THRESHOLD (-3)
+
+/* ------------------------ Mallinfo declarations ------------------------ */
+
+#if !NO_MALLINFO
+/*
+ This version of malloc supports the standard SVID/XPG mallinfo
+ routine that returns a struct containing usage properties and
+ statistics. It should work on any system that has a
+ /usr/include/malloc.h defining struct mallinfo. The main
+ declaration needed is the mallinfo struct that is returned (by-copy)
+ by mallinfo(). The malloinfo struct contains a bunch of fields that
+ are not even meaningful in this version of malloc. These fields are
+ are instead filled by mallinfo() with other numbers that might be of
+ interest.
+
+ HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
+ /usr/include/malloc.h file that includes a declaration of struct
+ mallinfo. If so, it is included; else a compliant version is
+ declared below. These must be precisely the same for mallinfo() to
+ work. The original SVID version of this struct, defined on most
+ systems with mallinfo, declares all fields as ints. But some others
+ define as unsigned long. If your system defines the fields using a
+ type of different width than listed here, you MUST #include your
+ system version and #define HAVE_USR_INCLUDE_MALLOC_H.
+*/
+
+/* #define HAVE_USR_INCLUDE_MALLOC_H */
+
+#ifdef HAVE_USR_INCLUDE_MALLOC_H
+#include "/usr/include/malloc.h"
+#else /* HAVE_USR_INCLUDE_MALLOC_H */
+#ifndef STRUCT_MALLINFO_DECLARED
+/* HP-UX (and others?) redefines mallinfo unless _STRUCT_MALLINFO is defined */
+#define _STRUCT_MALLINFO
+#define STRUCT_MALLINFO_DECLARED 1
+struct mallinfo {
+ MALLINFO_FIELD_TYPE arena; /* non-mmapped space allocated from system */
+ MALLINFO_FIELD_TYPE ordblks; /* number of free chunks */
+ MALLINFO_FIELD_TYPE smblks; /* always 0 */
+ MALLINFO_FIELD_TYPE hblks; /* always 0 */
+ MALLINFO_FIELD_TYPE hblkhd; /* space in mmapped regions */
+ MALLINFO_FIELD_TYPE usmblks; /* maximum total allocated space */
+ MALLINFO_FIELD_TYPE fsmblks; /* always 0 */
+ MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
+ MALLINFO_FIELD_TYPE fordblks; /* total free space */
+ MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
+};
+#endif /* STRUCT_MALLINFO_DECLARED */
+#endif /* HAVE_USR_INCLUDE_MALLOC_H */
+#endif /* NO_MALLINFO */
+
+/*
+ Try to persuade compilers to inline. The most critical functions for
+ inlining are defined as macros, so these aren't used for them.
+*/
+
+#ifndef FORCEINLINE
+ #if defined(__GNUC__)
+#define FORCEINLINE __inline __attribute__ ((always_inline))
+ #elif defined(_MSC_VER)
+ #define FORCEINLINE __forceinline
+ #endif
+#endif
+#ifndef NOINLINE
+ #if defined(__GNUC__)
+ #define NOINLINE __attribute__ ((noinline))
+ #elif defined(_MSC_VER)
+ #define NOINLINE __declspec(noinline)
+ #else
+ #define NOINLINE
+ #endif
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#ifndef FORCEINLINE
+ #define FORCEINLINE inline
+#endif
+#endif /* __cplusplus */
+#ifndef FORCEINLINE
+ #define FORCEINLINE
+#endif
+
+#if !ONLY_MSPACES
+
+/* ------------------- Declarations of public routines ------------------- */
+
+#ifndef USE_DL_PREFIX
+#define dlcalloc calloc
+#define dlfree free
+#define dlmalloc malloc
+#define dlmemalign memalign
+#define dlposix_memalign posix_memalign
+#define dlrealloc realloc
+#define dlrealloc_in_place realloc_in_place
+#define dlvalloc valloc
+#define dlpvalloc pvalloc
+#define dlmallinfo mallinfo
+#define dlmallopt mallopt
+#define dlmalloc_trim malloc_trim
+#define dlmalloc_stats malloc_stats
+#define dlmalloc_usable_size malloc_usable_size
+#define dlmalloc_footprint malloc_footprint
+#define dlmalloc_max_footprint malloc_max_footprint
+#define dlmalloc_footprint_limit malloc_footprint_limit
+#define dlmalloc_set_footprint_limit malloc_set_footprint_limit
+#define dlmalloc_inspect_all malloc_inspect_all
+#define dlindependent_calloc independent_calloc
+#define dlindependent_comalloc independent_comalloc
+#define dlbulk_free bulk_free
+#endif /* USE_DL_PREFIX */
+
+/*
+ malloc(size_t n)
+ Returns a pointer to a newly allocated chunk of at least n bytes, or
+ null if no space is available, in which case errno is set to ENOMEM
+ on ANSI C systems.
+
+ If n is zero, malloc returns a minimum-sized chunk. (The minimum
+ size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
+ systems.) Note that size_t is an unsigned type, so calls with
+ arguments that would be negative if signed are interpreted as
+ requests for huge amounts of space, which will often fail. The
+ maximum supported value of n differs across systems, but is in all
+ cases less than the maximum representable value of a size_t.
+*/
+DLMALLOC_EXPORT void* dlmalloc(size_t);
+
+/*
+ free(void* p)
+ Releases the chunk of memory pointed to by p, that had been previously
+ allocated using malloc or a related routine such as realloc.
+ It has no effect if p is null. If p was not malloced or already
+ freed, free(p) will by default cause the current program to abort.
+*/
+DLMALLOC_EXPORT void dlfree(void*);
+
+/*
+ calloc(size_t n_elements, size_t element_size);
+ Returns a pointer to n_elements * element_size bytes, with all locations
+ set to zero.
+*/
+DLMALLOC_EXPORT void* dlcalloc(size_t, size_t);
+
+/*
+ realloc(void* p, size_t n)
+ Returns a pointer to a chunk of size n that contains the same data
+ as does chunk p up to the minimum of (n, p's size) bytes, or null
+ if no space is available.
+
+ The returned pointer may or may not be the same as p. The algorithm
+ prefers extending p in most cases when possible, otherwise it
+ employs the equivalent of a malloc-copy-free sequence.
+
+ If p is null, realloc is equivalent to malloc.
+
+ If space is not available, realloc returns null, errno is set (if on
+ ANSI) and p is NOT freed.
+
+ if n is for fewer bytes than already held by p, the newly unused
+ space is lopped off and freed if possible. realloc with a size
+ argument of zero (re)allocates a minimum-sized chunk.
+
+ The old unix realloc convention of allowing the last-free'd chunk
+ to be used as an argument to realloc is not supported.
+*/
+DLMALLOC_EXPORT void* dlrealloc(void*, size_t);
+
+/*
+ realloc_in_place(void* p, size_t n)
+ Resizes the space allocated for p to size n, only if this can be
+ done without moving p (i.e., only if there is adjacent space
+ available if n is greater than p's current allocated size, or n is
+ less than or equal to p's size). This may be used instead of plain
+ realloc if an alternative allocation strategy is needed upon failure
+ to expand space; for example, reallocation of a buffer that must be
+ memory-aligned or cleared. You can use realloc_in_place to trigger
+ these alternatives only when needed.
+
+ Returns p if successful; otherwise null.
+*/
+DLMALLOC_EXPORT void* dlrealloc_in_place(void*, size_t);
+
+/*
+ memalign(size_t alignment, size_t n);
+ Returns a pointer to a newly allocated chunk of n bytes, aligned
+ in accord with the alignment argument.
+
+ The alignment argument should be a power of two. If the argument is
+ not a power of two, the nearest greater power is used.
+ 8-byte alignment is guaranteed by normal malloc calls, so don't
+ bother calling memalign with an argument of 8 or less.
+
+ Overreliance on memalign is a sure way to fragment space.
+*/
+DLMALLOC_EXPORT void* dlmemalign(size_t, size_t);
+
+/*
+ int posix_memalign(void** pp, size_t alignment, size_t n);
+ Allocates a chunk of n bytes, aligned in accord with the alignment
+ argument. Differs from memalign only in that it (1) assigns the
+ allocated memory to *pp rather than returning it, (2) fails and
+ returns EINVAL if the alignment is not a power of two (3) fails and
+ returns ENOMEM if memory cannot be allocated.
+*/
+DLMALLOC_EXPORT int dlposix_memalign(void**, size_t, size_t);
+
+/*
+ valloc(size_t n);
+ Equivalent to memalign(pagesize, n), where pagesize is the page
+ size of the system. If the pagesize is unknown, 4096 is used.
+*/
+DLMALLOC_EXPORT void* dlvalloc(size_t);
+
+/*
+ mallopt(int parameter_number, int parameter_value)
+ Sets tunable parameters The format is to provide a
+ (parameter-number, parameter-value) pair. mallopt then sets the
+ corresponding parameter to the argument value if it can (i.e., so
+ long as the value is meaningful), and returns 1 if successful else
+ 0. To workaround the fact that mallopt is specified to use int,
+ not size_t parameters, the value -1 is specially treated as the
+ maximum unsigned size_t value.
+
+ SVID/XPG/ANSI defines four standard param numbers for mallopt,
+ normally defined in malloc.h. None of these are use in this malloc,
+ so setting them has no effect. But this malloc also supports other
+ options in mallopt. See below for details. Briefly, supported
+ parameters are as follows (listed defaults are for "typical"
+ configurations).
+
+ Symbol param # default allowed param values
+ M_TRIM_THRESHOLD -1 2*1024*1024 any (-1 disables)
+ M_GRANULARITY -2 page size any power of 2 >= page size
+ M_MMAP_THRESHOLD -3 256*1024 any (or 0 if no MMAP support)
+*/
+DLMALLOC_EXPORT int dlmallopt(int, int);
+
+/*
+ malloc_footprint();
+ Returns the number of bytes obtained from the system. The total
+ number of bytes allocated by malloc, realloc etc., is less than this
+ value. Unlike mallinfo, this function returns only a precomputed
+ result, so can be called frequently to monitor memory consumption.
+ Even if locks are otherwise defined, this function does not use them,
+ so results might not be up to date.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_footprint(void);
+
+/*
+ malloc_max_footprint();
+ Returns the maximum number of bytes obtained from the system. This
+ value will be greater than current footprint if deallocated space
+ has been reclaimed by the system. The peak number of bytes allocated
+ by malloc, realloc etc., is less than this value. Unlike mallinfo,
+ this function returns only a precomputed result, so can be called
+ frequently to monitor memory consumption. Even if locks are
+ otherwise defined, this function does not use them, so results might
+ not be up to date.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_max_footprint(void);
+
+/*
+ malloc_footprint_limit();
+ Returns the number of bytes that the heap is allowed to obtain from
+ the system, returning the last value returned by
+ malloc_set_footprint_limit, or the maximum size_t value if
+ never set. The returned value reflects a permission. There is no
+ guarantee that this number of bytes can actually be obtained from
+ the system.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_footprint_limit();
+
+/*
+ malloc_set_footprint_limit();
+ Sets the maximum number of bytes to obtain from the system, causing
+ failure returns from malloc and related functions upon attempts to
+ exceed this value. The argument value may be subject to page
+ rounding to an enforceable limit; this actual value is returned.
+ Using an argument of the maximum possible size_t effectively
+ disables checks. If the argument is less than or equal to the
+ current malloc_footprint, then all future allocations that require
+ additional system memory will fail. However, invocation cannot
+ retroactively deallocate existing used memory.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_set_footprint_limit(size_t bytes);
+
+#if MALLOC_INSPECT_ALL
+/*
+ malloc_inspect_all(void(*handler)(void *start,
+ void *end,
+ size_t used_bytes,
+ void* callback_arg),
+ void* arg);
+ Traverses the heap and calls the given handler for each managed
+ region, skipping all bytes that are (or may be) used for bookkeeping
+ purposes. Traversal does not include include chunks that have been
+ directly memory mapped. Each reported region begins at the start
+ address, and continues up to but not including the end address. The
+ first used_bytes of the region contain allocated data. If
+ used_bytes is zero, the region is unallocated. The handler is
+ invoked with the given callback argument. If locks are defined, they
+ are held during the entire traversal. It is a bad idea to invoke
+ other malloc functions from within the handler.
+
+ For example, to count the number of in-use chunks with size greater
+ than 1000, you could write:
+ static int count = 0;
+ void count_chunks(void* start, void* end, size_t used, void* arg) {
+ if (used >= 1000) ++count;
+ }
+ then:
+ malloc_inspect_all(count_chunks, NULL);
+
+ malloc_inspect_all is compiled only if MALLOC_INSPECT_ALL is defined.
+*/
+DLMALLOC_EXPORT void dlmalloc_inspect_all(void(*handler)(void*, void *, size_t, void*),
+ void* arg);
+
+#endif /* MALLOC_INSPECT_ALL */
+
+#if !NO_MALLINFO
+/*
+ mallinfo()
+ Returns (by copy) a struct containing various summary statistics:
+
+ arena: current total non-mmapped bytes allocated from system
+ ordblks: the number of free chunks
+ smblks: always zero.
+ hblks: current number of mmapped regions
+ hblkhd: total bytes held in mmapped regions
+ usmblks: the maximum total allocated space. This will be greater
+ than current total if trimming has occurred.
+ fsmblks: always zero
+ uordblks: current total allocated space (normal or mmapped)
+ fordblks: total free space
+ keepcost: the maximum number of bytes that could ideally be released
+ back to system via malloc_trim. ("ideally" means that
+ it ignores page restrictions etc.)
+
+ Because these fields are ints, but internal bookkeeping may
+ be kept as longs, the reported values may wrap around zero and
+ thus be inaccurate.
+*/
+DLMALLOC_EXPORT struct mallinfo dlmallinfo(void);
+#endif /* NO_MALLINFO */
+
+/*
+ independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
+
+ independent_calloc is similar to calloc, but instead of returning a
+ single cleared space, it returns an array of pointers to n_elements
+ independent elements that can hold contents of size elem_size, each
+ of which starts out cleared, and can be independently freed,
+ realloc'ed etc. The elements are guaranteed to be adjacently
+ allocated (this is not guaranteed to occur with multiple callocs or
+ mallocs), which may also improve cache locality in some
+ applications.
+
+ The "chunks" argument is optional (i.e., may be null, which is
+ probably the most typical usage). If it is null, the returned array
+ is itself dynamically allocated and should also be freed when it is
+ no longer needed. Otherwise, the chunks array must be of at least
+ n_elements in length. It is filled in with the pointers to the
+ chunks.
+
+ In either case, independent_calloc returns this pointer array, or
+ null if the allocation failed. If n_elements is zero and "chunks"
+ is null, it returns a chunk representing an array with zero elements
+ (which should be freed if not wanted).
+
+ Each element must be freed when it is no longer needed. This can be
+ done all at once using bulk_free.
+
+ independent_calloc simplifies and speeds up implementations of many
+ kinds of pools. It may also be useful when constructing large data
+ structures that initially have a fixed number of fixed-sized nodes,
+ but the number is not known at compile time, and some of the nodes
+ may later need to be freed. For example:
+
+ struct Node { int item; struct Node* next; };
+
+ struct Node* build_list() {
+ struct Node** pool;
+ int n = read_number_of_nodes_needed();
+ if (n <= 0) return 0;
+ pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
+ if (pool == 0) die();
+ // organize into a linked list...
+ struct Node* first = pool[0];
+ for (i = 0; i < n-1; ++i)
+ pool[i]->next = pool[i+1];
+ free(pool); // Can now free the array (or not, if it is needed later)
+ return first;
+ }
+*/
+DLMALLOC_EXPORT void** dlindependent_calloc(size_t, size_t, void**);
+
+/*
+ independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
+
+ independent_comalloc allocates, all at once, a set of n_elements
+ chunks with sizes indicated in the "sizes" array. It returns
+ an array of pointers to these elements, each of which can be
+ independently freed, realloc'ed etc. The elements are guaranteed to
+ be adjacently allocated (this is not guaranteed to occur with
+ multiple callocs or mallocs), which may also improve cache locality
+ in some applications.
+
+ The "chunks" argument is optional (i.e., may be null). If it is null
+ the returned array is itself dynamically allocated and should also
+ be freed when it is no longer needed. Otherwise, the chunks array
+ must be of at least n_elements in length. It is filled in with the
+ pointers to the chunks.
+
+ In either case, independent_comalloc returns this pointer array, or
+ null if the allocation failed. If n_elements is zero and chunks is
+ null, it returns a chunk representing an array with zero elements
+ (which should be freed if not wanted).
+
+ Each element must be freed when it is no longer needed. This can be
+ done all at once using bulk_free.
+
+ independent_comallac differs from independent_calloc in that each
+ element may have a different size, and also that it does not
+ automatically clear elements.
+
+ independent_comalloc can be used to speed up allocation in cases
+ where several structs or objects must always be allocated at the
+ same time. For example:
+
+ struct Head { ... }
+ struct Foot { ... }
+
+ void send_message(char* msg) {
+ int msglen = strlen(msg);
+ size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
+ void* chunks[3];
+ if (independent_comalloc(3, sizes, chunks) == 0)
+ die();
+ struct Head* head = (struct Head*)(chunks[0]);
+ char* body = (char*)(chunks[1]);
+ struct Foot* foot = (struct Foot*)(chunks[2]);
+ // ...
+ }
+
+ In general though, independent_comalloc is worth using only for
+ larger values of n_elements. For small values, you probably won't
+ detect enough difference from series of malloc calls to bother.
+
+ Overuse of independent_comalloc can increase overall memory usage,
+ since it cannot reuse existing noncontiguous small chunks that
+ might be available for some of the elements.
+*/
+DLMALLOC_EXPORT void** dlindependent_comalloc(size_t, size_t*, void**);
+
+/*
+ bulk_free(void* array[], size_t n_elements)
+ Frees and clears (sets to null) each non-null pointer in the given
+ array. This is likely to be faster than freeing them one-by-one.
+ If footers are used, pointers that have been allocated in different
+ mspaces are not freed or cleared, and the count of all such pointers
+ is returned. For large arrays of pointers with poor locality, it
+ may be worthwhile to sort this array before calling bulk_free.
+*/
+DLMALLOC_EXPORT size_t dlbulk_free(void**, size_t n_elements);
+
+/*
+ pvalloc(size_t n);
+ Equivalent to valloc(minimum-page-that-holds(n)), that is,
+ round up n to nearest pagesize.
+ */
+DLMALLOC_EXPORT void* dlpvalloc(size_t);
+
+/*
+ malloc_trim(size_t pad);
+
+ If possible, gives memory back to the system (via negative arguments
+ to sbrk) if there is unused memory at the `high' end of the malloc
+ pool or in unused MMAP segments. You can call this after freeing
+ large blocks of memory to potentially reduce the system-level memory
+ requirements of a program. However, it cannot guarantee to reduce
+ memory. Under some allocation patterns, some large free blocks of
+ memory will be locked between two used chunks, so they cannot be
+ given back to the system.
+
+ The `pad' argument to malloc_trim represents the amount of free
+ trailing space to leave untrimmed. If this argument is zero, only
+ the minimum amount of memory to maintain internal data structures
+ will be left. Non-zero arguments can be supplied to maintain enough
+ trailing space to service future expected allocations without having
+ to re-obtain memory from the system.
+
+ Malloc_trim returns 1 if it actually released any memory, else 0.
+*/
+DLMALLOC_EXPORT int dlmalloc_trim(size_t);
+
+/*
+ malloc_stats();
+ Prints on stderr the amount of space obtained from the system (both
+ via sbrk and mmap), the maximum amount (which may be more than
+ current if malloc_trim and/or munmap got called), and the current
+ number of bytes allocated via malloc (or realloc, etc) but not yet
+ freed. Note that this is the number of bytes allocated, not the
+ number requested. It will be larger than the number requested
+ because of alignment and bookkeeping overhead. Because it includes
+ alignment wastage as being in use, this figure may be greater than
+ zero even when no user-level chunks are allocated.
+
+ The reported current and maximum system memory can be inaccurate if
+ a program makes other calls to system memory allocation functions
+ (normally sbrk) outside of malloc.
+
+ malloc_stats prints only the most commonly interesting statistics.
+ More information can be obtained by calling mallinfo.
+*/
+DLMALLOC_EXPORT void dlmalloc_stats(void);
+
+/*
+ malloc_usable_size(void* p);
+
+ Returns the number of bytes you can actually use in
+ an allocated chunk, which may be more than you requested (although
+ often not) due to alignment and minimum size constraints.
+ You can use this many bytes without worrying about
+ overwriting other allocated objects. This is not a particularly great
+ programming practice. malloc_usable_size can be more useful in
+ debugging and assertions, for example:
+
+ p = malloc(n);
+ assert(malloc_usable_size(p) >= 256);
+*/
+size_t dlmalloc_usable_size(void*);
+
+#endif /* ONLY_MSPACES */
+
+#if MSPACES
+
+/*
+ mspace is an opaque type representing an independent
+ region of space that supports mspace_malloc, etc.
+*/
+typedef void* mspace;
+
+/*
+ create_mspace creates and returns a new independent space with the
+ given initial capacity, or, if 0, the default granularity size. It
+ returns null if there is no system memory available to create the
+ space. If argument locked is non-zero, the space uses a separate
+ lock to control access. The capacity of the space will grow
+ dynamically as needed to service mspace_malloc requests. You can
+ control the sizes of incremental increases of this space by
+ compiling with a different DEFAULT_GRANULARITY or dynamically
+ setting with mallopt(M_GRANULARITY, value).
+*/
+DLMALLOC_EXPORT mspace create_mspace(size_t capacity, int locked);
+
+/*
+ destroy_mspace destroys the given space, and attempts to return all
+ of its memory back to the system, returning the total number of
+ bytes freed. After destruction, the results of access to all memory
+ used by the space become undefined.
+*/
+DLMALLOC_EXPORT size_t destroy_mspace(mspace msp);
+
+/*
+ create_mspace_with_base uses the memory supplied as the initial base
+ of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
+ space is used for bookkeeping, so the capacity must be at least this
+ large. (Otherwise 0 is returned.) When this initial space is
+ exhausted, additional memory will be obtained from the system.
+ Destroying this space will deallocate all additionally allocated
+ space (if possible) but not the initial base.
+*/
+DLMALLOC_EXPORT mspace create_mspace_with_base(void* base, size_t capacity, int locked);
+
+/*
+ mspace_track_large_chunks controls whether requests for large chunks
+ are allocated in their own untracked mmapped regions, separate from
+ others in this mspace. By default large chunks are not tracked,
+ which reduces fragmentation. However, such chunks are not
+ necessarily released to the system upon destroy_mspace. Enabling
+ tracking by setting to true may increase fragmentation, but avoids
+ leakage when relying on destroy_mspace to release all memory
+ allocated using this space. The function returns the previous
+ setting.
+*/
+DLMALLOC_EXPORT int mspace_track_large_chunks(mspace msp, int enable);
+
+
+/*
+ mspace_malloc behaves as malloc, but operates within
+ the given space.
+*/
+DLMALLOC_EXPORT void* mspace_malloc(mspace msp, size_t bytes);
+
+/*
+ mspace_free behaves as free, but operates within
+ the given space.
+
+ If compiled with FOOTERS==1, mspace_free is not actually needed.
+ free may be called instead of mspace_free because freed chunks from
+ any space are handled by their originating spaces.
+*/
+DLMALLOC_EXPORT void mspace_free(mspace msp, void* mem);
+
+/*
+ mspace_realloc behaves as realloc, but operates within
+ the given space.
+
+ If compiled with FOOTERS==1, mspace_realloc is not actually
+ needed. realloc may be called instead of mspace_realloc because
+ realloced chunks from any space are handled by their originating
+ spaces.
+*/
+DLMALLOC_EXPORT void* mspace_realloc(mspace msp, void* mem, size_t newsize);
+
+/*
+ mspace_calloc behaves as calloc, but operates within
+ the given space.
+*/
+DLMALLOC_EXPORT void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
+
+/*
+ mspace_memalign behaves as memalign, but operates within
+ the given space.
+*/
+DLMALLOC_EXPORT void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
+
+/*
+ mspace_independent_calloc behaves as independent_calloc, but
+ operates within the given space.
+*/
+DLMALLOC_EXPORT void** mspace_independent_calloc(mspace msp, size_t n_elements,
+ size_t elem_size, void* chunks[]);
+
+/*
+ mspace_independent_comalloc behaves as independent_comalloc, but
+ operates within the given space.
+*/
+DLMALLOC_EXPORT void** mspace_independent_comalloc(mspace msp, size_t n_elements,
+ size_t sizes[], void* chunks[]);
+
+/*
+ mspace_footprint() returns the number of bytes obtained from the
+ system for this space.
+*/
+DLMALLOC_EXPORT size_t mspace_footprint(mspace msp);
+
+/*
+ mspace_max_footprint() returns the peak number of bytes obtained from the
+ system for this space.
+*/
+DLMALLOC_EXPORT size_t mspace_max_footprint(mspace msp);
+
+
+#if !NO_MALLINFO
+/*
+ mspace_mallinfo behaves as mallinfo, but reports properties of
+ the given space.
+*/
+DLMALLOC_EXPORT struct mallinfo mspace_mallinfo(mspace msp);
+#endif /* NO_MALLINFO */
+
+/*
+ malloc_usable_size(void* p) behaves the same as malloc_usable_size;
+*/
+DLMALLOC_EXPORT size_t mspace_usable_size(const void* mem);
+
+/*
+ mspace_malloc_stats behaves as malloc_stats, but reports
+ properties of the given space.
+*/
+DLMALLOC_EXPORT void mspace_malloc_stats(mspace msp);
+
+/*
+ mspace_trim behaves as malloc_trim, but
+ operates within the given space.
+*/
+DLMALLOC_EXPORT int mspace_trim(mspace msp, size_t pad);
+
+/*
+ An alias for mallopt.
+*/
+DLMALLOC_EXPORT int mspace_mallopt(int, int);
+
+DLMALLOC_EXPORT void* mspace_get_aligned (mspace msp,
+ unsigned long long n_user_data_bytes,
+ unsigned long long align,
+ unsigned long long align_offset);
+
+DLMALLOC_EXPORT int mspace_is_heap_object (mspace msp, void *p);
+
+DLMALLOC_EXPORT void mspace_get_address_and_size (mspace msp,
+ unsigned long long *addrp,
+ unsigned long long *sizep);
+DLMALLOC_EXPORT void mspace_put (mspace msp, void *p);
+DLMALLOC_EXPORT void mspace_put_no_offset (mspace msp, void *p);
+DLMALLOC_EXPORT size_t mspace_usable_size_with_delta (const void *p);
+DLMALLOC_EXPORT void mspace_disable_expand (mspace msp);
+DLMALLOC_EXPORT void *mspace_least_addr (mspace msp);
+DLMALLOC_EXPORT void mheap_get_trace (u64 offset, u64 size);
+DLMALLOC_EXPORT void mheap_put_trace (u64 offset, u64 size);
+DLMALLOC_EXPORT int mspace_enable_disable_trace (mspace msp, int enable);
+
+#endif /* MSPACES */
+
+#ifdef __cplusplus
+} /* end of extern "C" */
+#endif /* __cplusplus */
+
+/*
+ ========================================================================
+ To make a fully customizable malloc.h header file, cut everything
+ above this line, put into file malloc.h, edit to suit, and #include it
+ on the next line, as well as in programs that use this malloc.
+ ========================================================================
+*/