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Diffstat (limited to 'lib/dlmalloc.h')
| -rw-r--r-- | lib/dlmalloc.h | 1143 |
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diff --git a/lib/dlmalloc.h b/lib/dlmalloc.h deleted file mode 100644 index 197b36667..000000000 --- a/lib/dlmalloc.h +++ /dev/null @@ -1,1143 +0,0 @@ -#ifndef DLMALLOC_H -#define DLMALLOC_H - -#define USE_DL_PREFIX - -/* - -#define FOOTERS 1 -#define DEBUG 1 -#define ABORT_ON_ASSERT_FAILURE 0 -*/ - -/* - 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/licenses/publicdomain. Send questions, - comments, complaints, performance data, etc to dl@cs.oswego.edu - -* Version 2.8.3 Thu Sep 22 11:16:15 2005 Doug Lea (dl at gee) - - 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-2.8.3.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 (default) - 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. - - Thread-safety: NOT thread-safe unless USE_LOCKS defined - When USE_LOCKS is defined, each public call to malloc, free, - etc is surrounded with either a pthread mutex or a win32 - spinlock (depending on WIN32). This 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 ptmalloc, which is derived from - a version of this malloc. (See http://www.malloc.de). - - 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. - - 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. - - ------------------------- 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. - -WIN32 default: defined if _WIN32 defined - Defining WIN32 sets up defaults for MS environment and compilers. - Otherwise defaults are for unix. - -MALLOC_ALIGNMENT default: (size_t)8 - 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.) - -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. - -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. - -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. - 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. See - near the end of this file for guidelines for creating a custom - version of MORECORE. - -MORECORE_CONTIGUOUS default: 1 (true) - 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. - -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 on unix - True if mmap clears memory so calloc doesn't need to. This is true - for standard unix mmap using /dev/zero. - -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. (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 - -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 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. - -*/ - -#ifndef WIN32 -#ifdef _WIN32 -#define WIN32 1 -#endif /* _WIN32 */ -#endif /* WIN32 */ -#ifdef WIN32 -#define WIN32_LEAN_AND_MEAN -#include <windows.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 MALLOC_FAILURE_ACTION -#define MMAP_CLEARS 0 /* WINCE and some others apparently don't clear */ -#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 -#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) - -#ifndef ONLY_MSPACES -#define ONLY_MSPACES 0 -#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)8U) -#endif /* MALLOC_ALIGNMENT */ -#ifndef FOOTERS -#define FOOTERS 0 -#endif /* FOOTERS */ -#ifndef ABORT -#define ABORT abort() -#endif /* ABORT */ -#ifndef ABORT_ON_ASSERT_FAILURE -#define ABORT_ON_ASSERT_FAILURE 1 -#endif /* ABORT_ON_ASSERT_FAILURE */ -#ifndef PROCEED_ON_ERROR -#define PROCEED_ON_ERROR 0 -#endif /* PROCEED_ON_ERROR */ -#ifndef USE_LOCKS -#define USE_LOCKS 0 -#endif /* USE_LOCKS */ -#ifndef INSECURE -#define INSECURE 0 -#endif /* INSECURE */ -#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 -#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 */ -#ifndef MORECORE -#define MORECORE sbrk -#endif /* MORECORE */ -#ifndef MORECORE_CONTIGUOUS -#define MORECORE_CONTIGUOUS 1 -#endif /* MORECORE_CONTIGUOUS */ -#endif /* HAVE_MORECORE */ -#ifndef DEFAULT_GRANULARITY -#if MORECORE_CONTIGUOUS -#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 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 */ - -/* - 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 */ - -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 /* HAVE_USR_INCLUDE_MALLOC_H */ -#endif /* NO_MALLINFO */ - -#ifdef __cplusplus -extern "C" { -#endif /* __cplusplus */ - -#if !ONLY_MSPACES - -/* ------------------- Declarations of public routines ------------------- */ - -#ifndef USE_DL_PREFIX -#define dlcalloc calloc -#define dlfree free -#define dlmalloc malloc -#define dlmemalign memalign -#define dlrealloc realloc -#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 dlindependent_calloc independent_calloc -#define dlindependent_comalloc independent_comalloc -#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. -*/ -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. -*/ -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. -*/ -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. -*/ - -void* dlrealloc(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. -*/ -void* dlmemalign(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. -*/ -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. 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 (MAX_SIZE_T 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) -*/ -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. -*/ -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. -*/ -size_t dlmalloc_max_footprint(void); - -#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. -*/ -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 individually freed when it is no longer - needed. If you'd like to instead be able to free all at once, you - should instead use regular calloc and assign pointers into this - space to represent elements. (In this case though, you cannot - independently free elements.) - - 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; - } -*/ -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 individually freed when it is no longer - needed. If you'd like to instead be able to free all at once, you - should instead use a single regular malloc, and assign pointers at - particular offsets in the aggregate space. (In this case though, you - cannot independently free elements.) - - 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. -*/ -void** dlindependent_comalloc(size_t, size_t*, void**); - - -/* - pvalloc(size_t n); - Equivalent to valloc(minimum-page-that-holds(n)), that is, - round up n to nearest pagesize. - */ -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. -*/ -int dlmalloc_trim(size_t); - -/* - 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*); - -/* - 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. -*/ -void dlmalloc_stats(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). -*/ -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. -*/ -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. -*/ -mspace create_mspace_with_base(void* base, size_t capacity, int locked); - -/* - mspace_malloc behaves as malloc, but operates within - the given space. -*/ -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. -*/ -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. -*/ -void* mspace_realloc(mspace msp, void* mem, size_t newsize); - -/* - mspace_calloc behaves as calloc, but operates within - the given space. -*/ -void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size); - -/* - mspace_memalign behaves as memalign, but operates within - the given space. -*/ -void* mspace_memalign(mspace msp, size_t alignment, size_t bytes); - -/* - mspace_independent_calloc behaves as independent_calloc, but - operates within the given space. -*/ -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. -*/ -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. -*/ -size_t mspace_footprint(mspace msp); - -/* - mspace_max_footprint() returns the peak number of bytes obtained from the - system for this space. -*/ -size_t mspace_max_footprint(mspace msp); - - -#if !NO_MALLINFO -/* - mspace_mallinfo behaves as mallinfo, but reports properties of - the given space. -*/ -struct mallinfo mspace_mallinfo(mspace msp); -#endif /* NO_MALLINFO */ - -/* - mspace_malloc_stats behaves as malloc_stats, but reports - properties of the given space. -*/ -void mspace_malloc_stats(mspace msp); - -/* - mspace_trim behaves as malloc_trim, but - operates within the given space. -*/ -int mspace_trim(mspace msp, size_t pad); - -/* - An alias for mallopt. -*/ -int mspace_mallopt(int, int); - -#endif /* MSPACES */ - -#ifdef __cplusplus -}; /* end of extern "C" */ -#endif /* __cplusplus */ - -#endif /* DLMALLOC_H */ |