/* * To do: * - strdup? maybe shouldn't bother yet, it seems difficult to get includes * right using dlmalloc.h * - add STD_C prototyping * - adhere to comment conventions * - maybe fix ALLOCFILL vs. MOATFILL in do_init_realloced_chunk() * - keep a list of mmaped regions for checking in malloc_update_mallinfo() * - I think memalign() is wrong: it aligns the chunk rather than the memory * portion of the chunk. * - "& -alignment" in memalign() is suspect: should use "& ~alignment" * instead? * - malloc.h doesn't need malloc_COPY or probably a bunch of other stuff * - add mallopt options for e.g. fill? * - come up with a non-BBC version of M_C * - document necessity of checking chunk address in do_check_chunk prior to * accessing any of its fields * Done: * minor speedup due to extend check before mremap * minor speedup due to returning malloc() result in memalign() if aligned * made malloc_update_mallinfo() check alloced regions at start of sbrk area * fixed bug: After discovering foreign sbrk, if old_top was MINSIZE, would * reduce old_top_size to 0, thus making inuse(old_top) return 0; other * functions would consequently attempt to access old_top->{fd,bk}, which * were invalid. This is in malloc_extend_top(), in the "double * fencepost" section. * Documentation: * malloc_usable_size(P) is equivalent to realloc(P, malloc_usable_size(P)) * * $Log$ * Revision 1.8 2004/01/20 19:36:34 cgf * * include/cygwin/version.h: Bump DLL minor number to 8. * * cygmalloc.h: Make more concessions to attempts to get debugging malloc * working. * * debug.h: Ditto. * * dlmalloc.cc: Ditto. * * dlmalloc.h: Ditto. * * malloc_wrapper.cc: Ditto. * * perthread.h (perthread::create): Use calloc to ensure zeroed memory. * * Revision 1.7 2003/09/25 00:37:16 cgf * * devices.cc: New file. * * devices.gperf: New file. * * devices.shilka: New file. * * cygwin-gperf: New file. * * cygwin-shilka: New file. * * fhandler_fifo.cc: New file. * * fhandler_nodevice.cc : New file. Reorganize headers so that path.h precedes * fhandler.h throughout. Remove device argument and unit arguments from fhandler * constructors throughout. Remove pc arguments to fhandler functions and use * internal pc element instead, throughout. Use dev element in pc throughout. * Use major/minor elements rather than units and device numbers previously in * fhandler class. Use correct methods for fhandler file names rather than * directly accessing file name variables, throughout. * * Makefile.in (DLL_OFILES): Add devices.o, fhandler_fifo.o * * dcrt0.cc (dll_crt0_1): Call device::init. * * devices.h: Renumber devices based on more Linux-like major/minor numbers. * Add more devices. Declare standard device storage. * (device): Declare struct. * * dir.cc (opendir): Use new 'build_fh_name' to construct a fhandler_* type. * * dtable.cc (dtable::get_debugger_info): Ditto. * (cygwin_attach_handle_to_fd): Ditto. * (dtable::release): Remove special FH_SOCKET case in favor of generic * "need_fixup_before" test. * (dtable::init_std_file_from_handle): Use either build_fh_dev or build_fh_name * to build standard fhandler. * (dtable::build_fh_name): Renamed from dtable::build_fhandler_from_name. Move * out of dtable class. Don't accept a path_conv argument. Just build it here * and pass it to: * (build_fh_pc): Renamed from dtable::build_fhandler. Move out of dtable class. * Use intrinsic device type in path_conv to create new fhandler. * (build_fh_dev): Renamed from dtable::build_fhandler. Move out of dtable class. * Simplify arguments to just take new 'device' type and a name. Just return * pointer to fhandler rather than trying to insert into dtable. * (dtable::dup_worker): Accommodate above build_fh name changes. * (dtable::find_fifo): New (currently broken) function. * (handle_to_fn): Use strechr for efficiency. * * dtable.h: Reflect above build_fh name changes and argument differences. * (fhandler_base *&operator []): Return self rather than copy of self. * * fhandler.cc (fhandler_base::operator =): Use pc element to set normalized * path. * (fhandler_base::set_name): Ditto. * (fhandler_base::raw_read): Use method to access name. * (fhandler_base::write): Correctly use get_output_handle rather than get_handle. * (handler_base::device_access_denied): New function. * (fhandler_base::open): Eliminate pc argument and use pc element of * fhandler_base throughout. * (fhandler_base::fstat): Detect if device is based in filesystem and use * fstat_fs to calculate stat, if so. * (fhandler_base::fhandler_base): Eliminate handling of file names and, instead, * just free appropriate component from pc. * (fhandler_base::opendir): Remove path_conv parameter. * * fhandler.h: Remove all device flags. * (fhandler_base::pc): New element. * (fhandler_base::set_name): Change argument to path_conv. * (fhandler_base::error): New function. * (fhandler_base::exists): New function. * (fhandler_base::pc_binmode): New function. * (fhandler_base::dev): New function. * (fhandler_base::open_fs): New function. * (fhandler_base::fstat_fs): New function. * (fhandler_base::fstat_by_name): New function. * (fhandler_base::fstat_by_handle): New function. * (fhandler_base::isfifo): New function. * (fhandler_base::is_slow): New function. * (fhandler_base::is_auto_device): New function. * (fhandler_base::is_fs_special): New function. * (fhandler_base::device_access_denied): New function. * (fhandler_base::operator DWORD&): New operator. * (fhandler_base::get_name): Return normalized path from pc. * (fhandler_base::get_win32_name): Return windows path from pc. * (fhandler_base::isdevice): Renamed from is_device. * (fhandler_base::get_native_name): Return device format. * (fhandler_fifo): New class. * (fhandler_nodevice): New class. * (select_stuff::device_specific): Remove array. * (select_stuff::device_specific_pipe): New class element. * (select_stuff::device_specific_socket): New class element. * (select_stuff::device_specific_serial): New class element. * (select_stuff::select_stuff): Initialize new elements. * * fhandler_disk_file.cc (fhandler_base::fstat_by_handle): Move to base class * from fhandler_disk_file. * (fhandler_base::fstat_by_name): Ditto. * (fhandler_base::fstat_by_name): Ditto. * (fhandler_disk_file::open): Move most functionality into * fhandler_base::open_fs. * (fhandler_base::open_fs): New function. * (fhandler_disk_file::close): Move most functionality into * fhandler_base::close_fs. * (fhandler_base::close_fs): New function. * * fhandler_mem.cc (fhandler_dev_mem::open): Use device name in debugging * output. * * fhandler_socket.cc (fhandler_socket::set_connect_secret): Copy standard * urandom device into appropriate place. * (fhandler_socket::accept): Reflect change in fdsock return value. * * fhandler_tty.cc: See "throughouts" above. * * net.cc: Accommodate fdsock change throughout. * (fdsock): Return success or failure, accept fd argument and device argument. * * path.cc (symlink_info::major): New element. * (symlink_info::minor): New element. * (symlink_info::parse_device): Declare new function. * (fs_info::update): Accommodate changes in path_conv class. * (path_conv::fillin): Ditto. * (path_conv::return_and_clear_normalized_path): Eliminate. * (path_conv::set_normalized_path): New function. * (path_conv::path_conv): Set info in dev element. Use path_conv methods Check * for FH_FS rather than FH_BAD to indicate when to fill in filesystem stuff. * where appropriate rather than direct access. Use set_normalized_path to set * normalized path. * (windows_device_names): Eliminate. * (get_dev): Ditto. * (get_raw_device_number): Ditto. * (get_device_number): Ditto. * (win32_device_name): Call new device name parser to do most of the heavy * lifting. * (mount_info::conv_to_win32_path): Fill in dev field as appropriate. * (symlink_worker): Handle new device files. * (symlink_info::check): Ditto. * (symlink_info::parse_device): Define new function. * * path.h (executable_states): Move here from fhandler.h. * (fs_info): Rename variables to *_storage and create methods for accessing same. * (path_conv): Add dev element, remove devn and unit and adjust inline methods to * accommodate. * (set_normalized_path): Declare new function. * * pinfo.cc (_pinfo::commune_recv): Add broken support for handling fifos. * (_pinfo::commune_send): Ditto. * * pipe.cc (fhandler_pipe::close): check for existence of handle before closing * it. * (handler_pipe::create): Rename from make_pipe. Change arguments to accept * fhandler_pipe array. Accommodate fifos. * (pipe): Rework to deal with fhandler_pipe::create changes. * (_pipe): Ditto. * * select.cc: Use individual device_specific types throughout rather than * indexing with obsolete device number. * (set_bits): Use is_socket call rather than checking device number. * * shared_info.h (CURR_MOUNT_MAGIC): Update. * (conv_to_win32_path): Reflect addition of device argument. * * syscalls.cc (mknod_worker): New function. * (open): Use build_fh_name to build fhandler. * (chown_worker): Detect if this is an 'auto' device rather than an on-filesystem * device and handle appropriately. * (chmod_device): New function. * (chmod): Detect if this is an 'auto' device rather than an on-filesystem device * and handle appropriately. Use chmod_device to set mode of in-filesystem * devices. * (stat_worker): Eliminate path_conv argument. Call build_fh_name to construct * fhandler. Use fh->error() rather than pc->error to detect errors in fhandler * construction. * (access_worker): New function pulled from access. Accommodate in-filesystem * devices. * (access): Use access_worker. * (fpathconf): Detect if this is an 'auto' device rather than an on-filesystem * device and handle appropriately. * (mknod_worker): New function. * (mknod32): New function. * (chroot): Free normalized path -- assuming it was actually cmalloced. * * tty.cc (create_tty_master): Tweak for new device class. * (tty::common_init): Ditto. * * winsup.h (stat_worker): Remove. * (symlink_worker): Declare. * * exceptions.cc (set_process_mask): Just call sig_dispatch_pending and don't * worry about pending_signals since sig_dispatch_pending should always do the * right thing now. * (sig_handle): Reorganize SIGCONT handling to more closely conform to SUSv3. * * pinfo.h: Move __SIG enum to sigproc.h. * (PICOM_FIFO): New enum element. * (_pinfo): Remove 'thread2signal' stuff throughout class. * (_pinfo::commune_send): Make varargs. * (_pinfo::sigtodo): Eliminate. * (_pinfo::thread2signal): Ditto. * * signal.cc (kill_worker): Eliminate call to setthread2signal. * * sigproc.cc (local_sigtodo): Eliminate. * (getlocal_sigtodo): Ditto. * (sigelem): New class. * (pending_signals): New class. * (sigqueue): New variable, start of sigqueue linked list. * (sigcatch_nonmain): Eliminate. * (sigcatch_main): Eliminate. * (sigcatch_nosync): Eliminate. * (sigcomplete_nonmain): Eliminate. * (pending_signals): Eliminate. * (sig_clear): Call signal thread to clear pending signals, unless already in * signal thread. * (sigpending): Call signal thread to get pending signals. * (sig_dispatch_pending): Eliminate use of pending_signals and just check * sigqueue. * (sigproc_terminate): Eliminate all of the obsolete semaphore stuff. Close * signal pipe handle. * (sig_send): Eliminate all of the obsolete semaphore stuff and use pipe to send * signals. * (getevent): Eliminate. * (pending_signals::add): New function. * (pending_signals::del): New function. * (pending_signals::next): New function. * (wait_sig): Eliminate all of the obsolete semaphore stuff. Use pipe to * communicate and maintain a linked list of signals. * * sigproc.h: Move __SIG defines here. Add __SIGPENDING. * (sig_dispatch_pending): Remove "C" specifier. * (sig_handle): Accept a mask argument. * * thread.cc: Remove signal handling considerations throughout. * * Revision 1.5.52.1 2003/09/02 02:31:08 cgf * merge from trunk * * Revision 1.6 2003/08/31 18:26:58 cgf * * Makefile.in (MALLOC_OFILES): Always fill in with correct malloc object. * * configure.in: Fill in MALLOC_OFILES with either debugging or regular malloc. * * configure: Regenerate. * * dlmalloc.c: Make various fruitless changes to attempt to get to work. * * dlmalloc.h: Ditto. * * malloc.cc (free): Check malloc pool when debugging. * * path.cc (win32_device_name): Eliminate compiler warning. * * sigproc.cc (sig_dispatch_pending): Remove use of was_pending. Let * thisframe.call_signal_handler decide if handler should be called rather than * using bogus was_pending check. * * exceptions.cc (interrupt_setup): Remove accidentally checked in debugging * code. * * heap.cc (sbrk): Save rounded addess in user_heap_max. * * Revision 1.5 2001/10/03 03:49:25 cgf * * cygheap.cc (cfree): Remove malloc debugging probe. * * dlmalloc.c (errprint): Remove abort() call which causes interesting error * message printing to abort prematurely. * * environ.cc: Sprinkle MALLOC_CHECKs liberally throughout. * (_addenv): Allocate two empty elements at end of environ to * (apparently) work around problems with some buggy applications. * (winenv): Avoid calling alloca if no forced environment variable is present. * * * exceptions.cc (open_stackdumpfile): Don't print "Dumping stack trace to..." * when running in a cygwin environment (i.e., the parent is a cygwin process). * * * dtable.cc (dtable::init_std_file_from_handle): Move device type detection * code from build_fhandler here since it is only used by this function. * (dtable::build_fhandler_from_name): New method. Renamed from * dtable::build_fhandler. * (dtable::build_fhandler): Use build_fhandler_from_name. * (cygwin_attach_handle_to_fd): Ditto. * * syscalls.cc (_open): Ditto. * (stat_worker): Ditto. * * dtable.h (dtable::build_fhandler_from_name): Rename declaration from * dtable::build_fhandler. * * Revision 1.4 2001/09/07 21:32:04 cgf * * cygheap.h (init_cygheap): Move heap pointers here. * * include/sys/cygwin.h (perprocess): Remove heap pointers. * * dcrt0.cc (__cygwin_user_data): Reflect obsolete perprocess stuff. * (_dll_crt0): Don't initialize heap pointers. * (cygwin_dll_init): Ditto. * (release_upto): Use heap pointers from cygheap. * * heap.h: Ditto. * * fork.cc (fork_parent): Ditto. Don't set heap pointers in ch. * (fork_child): Remove obsolete sigproc_fixup_after_fork. * * shared.cc (memory_init): Reorganize so that cygheap initialization is called * prior to regular heap since regular heap uses cygheap now. * * sigproc.cc (proc_subproc): Eliminate zombies allocation. * (sigproc_init): Move zombies alloation here. Don't free up array on fork, just * reuse it. * (sigproc_fixup_after_fork): Eliminate. * * sigproc.h: Ditto. * * include/cygwin/version.h: Reflect change to perprocess structure. * * Revision 1.3 2001/06/26 14:47:48 cgf * * mmap.cc: Clean up *ResourceLock calls throughout. * * thread.cc (pthread_cond::TimedWait): Check for WAIT_TIMEOUT as well as * WAIT_ABANDONED. * (__pthread_cond_timedwait): Calculate a relative wait from the abstime * parameter. * * Revision 1.2 2001/06/24 22:26:49 cgf * forced commit * * Revision 1.1 2001/04/24 15:25:30 duda * * dlmalloc.c: New file. Port of Doug Lea's malloc * * dlmalloc.h: Ditto. * * Makefile.in: Add support for MALLOC_DEBUG * * config.h.in: Ditto. * * winsup.h: Ditto. * * configure.in: Add --enable-malloc-debugging option. * * configure: Regenerate. * * debug.h: Include declarations for debugging malloc. * * tty.cc (grantpt): Fix definition. * (unlockpt): Ditto. * * Revision 1.1 1997/12/24 18:34:47 nsd * Initial revision * */ /* ---------- To make a malloc.h, start cutting here ------------ */ /* A version of malloc/free/realloc written by Doug Lea and released to the public domain. Send questions/comments/complaints/performance data to dl@cs.oswego.edu * VERSION 2.6.4 Thu Nov 28 07:54:55 1996 Doug Lea (dl at gee) Note: There may be an updated version of this malloc obtainable at ftp://g.oswego.edu/pub/misc/malloc.c Check before installing! * Why use this malloc? 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 a high-level description, see http://g.oswego.edu/dl/html/malloc.html * Synopsis of public routines (Much fuller descriptions are contained in the program documentation below.) malloc(size_t n); Return a pointer to a newly allocated chunk of at least n bytes, or null if no space is available. free(Void_t* p); Release the chunk of memory pointed to by p, or no effect if p is null. realloc(Void_t* p, size_t n); Return 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. If p is null, equivalent to malloc. Unless the #define realloc_ZERO_BYTES_FREES below is set, realloc with a size argument of zero (re)allocates a minimum-sized chunk. memalign(size_t alignment, size_t n); Return a pointer to a newly allocated chunk of n bytes, aligned in accord with the alignment argument, which must be a power of two. valloc(size_t n); Equivalent to memalign(pagesize, n), where pagesize is the page size of the system (or as near to this as can be figured out from all the includes/defines below.) pvalloc(size_t n); Equivalent to valloc(minimum-page-that-holds(n)), that is, round up n to nearest pagesize. calloc(size_t unit, size_t quantity); Returns a pointer to quantity * unit bytes, with all locations set to zero. cfree(Void_t* p); Equivalent to free(p). malloc_trim(size_t pad); Release all but pad bytes of freed top-most memory back to the system. Return 1 if successful, else 0. malloc_usable_size(Void_t* p); Report the number usable allocated bytes associated with allocated chunk p. This may or may not report more bytes than were requested, due to alignment and minimum size constraints. malloc_stats(); Prints brief summary statistics on stderr. mallinfo() Returns (by copy) a struct containing various summary statistics. mallopt(int parameter_number, int parameter_value) Changes one of the tunable parameters described below. Returns 1 if successful in changing the parameter, else 0. * Vital statistics: Alignment: 8-byte 8 byte alignment is currently hardwired into the design. This seems to suffice for all current machines and C compilers. Assumed pointer representation: 4 or 8 bytes Code for 8-byte pointers is untested by me but has worked reliably by Wolfram Gloger, who contributed most of the changes supporting this. Assumed size_t representation: 4 or 8 bytes Note that size_t is allowed to be 4 bytes even if pointers are 8. Minimum overhead per allocated chunk: 4 or 8 bytes Each malloced chunk has a hidden overhead of 4 bytes holding size and status information. Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead) 8-byte ptrs: 24/32 bytes (including, 4/8 overhead) When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte ptrs but 4 byte size) or 24 (for 8/8) additional bytes are needed; 4 (8) for a trailing size field and 8 (16) bytes for free list pointers. Thus, the minimum allocatable size is 16/24/32 bytes. Even a request for zero bytes (i.e., malloc(0)) returns a pointer to something of the minimum allocatable size. Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes 8-byte size_t: 2^63 - 16 bytes It is assumed that (possibly signed) size_t bit values suffice to represent chunk sizes. `Possibly signed' is due to the fact that `size_t' may be defined on a system as either a signed or an unsigned type. To be conservative, values that would appear as negative numbers are avoided. Requests for sizes with a negative sign bit will return a minimum-sized chunk. Maximum overhead wastage per allocated chunk: normally 15 bytes Alignnment demands, plus the minimum allocatable size restriction make the normal worst-case wastage 15 bytes (i.e., up to 15 more bytes will be allocated than were requested in malloc), with two exceptions: 1. Because requests for zero bytes allocate non-zero space, the worst case wastage for a request of zero bytes is 24 bytes. 2. For requests >= mmap_threshold that are serviced via mmap(), the worst case wastage is 8 bytes plus the remainder from a system page (the minimal mmap unit); typically 4096 bytes. * Limitations Here are some features that are NOT currently supported * No user-definable hooks for callbacks and the like. * No automated mechanism for fully checking that all accesses to malloced memory stay within their bounds. * No support for compaction. * Synopsis of compile-time options: People have reported using previous versions of this malloc on all versions of Unix, sometimes by tweaking some of the defines below. It has been tested most extensively on Solaris and Linux. It is also reported to work on WIN32 platforms. People have also reported adapting this malloc for use in stand-alone embedded systems. The implementation is in straight, hand-tuned ANSI C. Among other consequences, it uses a lot of macros. Because of this, to be at all usable, this code should be compiled using an optimizing compiler (for example gcc -O2) that can simplify expressions and control paths. __STD_C (default: derived from C compiler defines) Nonzero if using ANSI-standard C compiler, a C++ compiler, or a C compiler sufficiently close to ANSI to get away with it. DEBUG (default: NOT defined) Define to enable debugging. Adds fairly extensive assertion-based checking to help track down memory errors, but noticeably slows down execution. realloc_ZERO_BYTES_FREES (default: NOT defined) Define this if you think that realloc(p, 0) should be equivalent to free(p). Otherwise, since malloc returns a unique pointer for malloc(0), so does realloc(p, 0). HAVE_memcpy (default: defined) Define if you are not otherwise using ANSI STD C, but still have memcpy and memset in your C library and want to use them. Otherwise, simple internal versions are supplied. USE_memcpy (default: 1 if HAVE_memcpy is defined, 0 otherwise) Define as 1 if you want the C library versions of memset and memcpy called in realloc and calloc (otherwise macro versions are used). At least on some platforms, the simple macro versions usually outperform libc versions. HAVE_MMAP (default: defined as 1) Define to non-zero to optionally make malloc() use mmap() to allocate very large blocks. HAVE_MREMAP (default: defined as 0 unless Linux libc set) Define to non-zero to optionally make realloc() use mremap() to reallocate very large blocks. malloc_getpagesize (default: derived from system #includes) Either a constant or routine call returning the system page size. HAVE_USR_INCLUDE_malloc_H (default: NOT defined) Optionally define if you are on a system with a /usr/include/malloc.h that declares struct mallinfo. It is not at all necessary to define this even if you do, but will ensure consistency. INTERNAL_SIZE_T (default: size_t) Define to a 32-bit type (probably `unsigned int') if you are on a 64-bit machine, yet do not want or need to allow malloc requests of greater than 2^31 to be handled. This saves space, especially for very small chunks. INTERNAL_LINUX_C_LIB (default: NOT defined) Defined only when compiled as part of Linux libc. Also note that there is some odd internal name-mangling via defines (for example, internally, `malloc' is named `mALLOc') needed when compiling in this case. These look funny but don't otherwise affect anything. WIN32 (default: undefined) Define this on MS win (95, nt) platforms to compile in sbrk emulation. LACKS_UNISTD_H (default: undefined) Define this if your system does not have a . MORECORE (default: sbrk) The name of the routine to call to obtain more memory from the system. MORECORE_FAILURE (default: -1) The value returned upon failure of MORECORE. MORECORE_CLEARS (default 0) True (1) if the routine mapped to MORECORE zeroes out memory (which holds for sbrk). DEFAULT_TRIM_THRESHOLD DEFAULT_TOP_PAD DEFAULT_MMAP_THRESHOLD DEFAULT_MMAP_MAX Default values of tunable parameters (described in detail below) controlling interaction with host system routines (sbrk, mmap, etc). These values may also be changed dynamically via mallopt(). The preset defaults are those that give best performance for typical programs/systems. */ /* Preliminaries */ #ifndef __STD_C #ifdef __STDC__ #define __STD_C 1 #else #if __cplusplus #define __STD_C 1 #else #define __STD_C 0 #endif /*__cplusplus*/ #endif /*__STDC__*/ #endif /*__STD_C*/ #ifndef Void_t #if __STD_C #define Void_t void #else #define Void_t char #endif #endif /*Void_t*/ #define __MALLOC_H_INCLUDED #if __STD_C #include /* for size_t */ #else #include #endif #ifdef __cplusplus extern "C" { #endif #include #include "cygmalloc.h" #define __INSIDE_CYGWIN__ #include /* needed for malloc_stats */ #include /* Compile-time options */ /* Debugging: Because freed chunks may be overwritten with link fields, this malloc will often die when freed memory is overwritten by user programs. This can be very effective (albeit in an annoying way) in helping track down dangling pointers. If you compile with -DDEBUG, a number of assertion checks are enabled that will catch more memory errors. You probably won't be able to make much sense of the actual assertion errors, but they should help you locate incorrectly overwritten memory. 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 summmaries. (By nature, mmapped regions cannot be checked very much automatically.) Setting DEBUG may also be helpful if you are trying to modify this code. The assertions in the check routines spell out in more detail the assumptions and invariants underlying the algorithms. */ #ifdef MALLOC_DEBUG #define DEBUG 1 #define DEBUG1 1 #define DEBUG2 1 #define DEBUG3 1 #endif #if DEBUG #include #else #define assert(x) ((void)0) #endif /* INTERNAL_SIZE_T is the word-size used for internal bookkeeping of chunk sizes. On a 64-bit machine, you can reduce malloc overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' at the expense of not being able to handle requests greater than 2^31. This limitation is hardly ever a concern; you are encouraged to set this. However, the default version is the same as size_t. */ #ifndef INTERNAL_SIZE_T #define INTERNAL_SIZE_T size_t #endif /* realloc_ZERO_BYTES_FREES 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). */ /* #define realloc_ZERO_BYTES_FREES */ /* WIN32 causes an emulation of sbrk to be compiled in mmap-based options are not currently supported in WIN32. */ /* #define WIN32 */ #ifdef WIN32 #define MORECORE wsbrk #define HAVE_MMAP 0 #endif /* HAVE_memcpy should be defined if you are not otherwise using ANSI STD C, but still have memcpy and memset in your C library and want to use them in calloc and realloc. Otherwise simple macro versions are defined here. USE_memcpy should be defined as 1 if you actually want to have memset and memcpy called. People report that the macro versions are often enough faster than libc versions on many systems that it is better to use them. */ #define HAVE_memcpy #ifndef USE_memcpy #ifdef HAVE_memcpy #define USE_memcpy 1 #else #define USE_memcpy 0 #endif #endif #if (__STD_C || defined(HAVE_memcpy)) #if __STD_C void* memset(void*, int, size_t); void* memcpy(void*, const void*, size_t); #else Void_t* memset(); Void_t* memcpy(); #endif #endif #ifndef DEBUG3 #if USE_memcpy /* The following macros are only invoked with (2n+1)-multiples of INTERNAL_SIZE_T units, with a positive integer n. This is exploited for fast inline execution when n is small. */ #define malloc_ZERO(charp, nbytes) \ do { \ INTERNAL_SIZE_T mzsz = (nbytes); \ if(mzsz <= 9*sizeof(mzsz)) { \ INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp); \ if(mzsz >= 5*sizeof(mzsz)) { *mz++ = 0; \ *mz++ = 0; \ if(mzsz >= 7*sizeof(mzsz)) { *mz++ = 0; \ *mz++ = 0; \ if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0; \ *mz++ = 0; }}} \ *mz++ = 0; \ *mz++ = 0; \ *mz = 0; \ } else memset((charp), 0, mzsz); \ } while(0) #define malloc_COPY(dest,src,nbytes) \ do { \ INTERNAL_SIZE_T mcsz = (nbytes); \ if(mcsz <= 9*sizeof(mcsz)) { \ INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src); \ INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest); \ if(mcsz >= 5*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ *mcdst++ = *mcsrc++; \ if(mcsz >= 7*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ *mcdst++ = *mcsrc++; \ if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ *mcdst++ = *mcsrc++; }}} \ *mcdst++ = *mcsrc++; \ *mcdst++ = *mcsrc++; \ *mcdst = *mcsrc ; \ } else memcpy(dest, src, mcsz); \ } while(0) #else /* !USE_memcpy */ /* Use Duff's device for good zeroing/copying performance. */ #define malloc_ZERO(charp, nbytes) \ do { \ INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \ long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ switch (mctmp) { \ case 0: for(;;) { *mzp++ = 0; \ case 7: *mzp++ = 0; \ case 6: *mzp++ = 0; \ case 5: *mzp++ = 0; \ case 4: *mzp++ = 0; \ case 3: *mzp++ = 0; \ case 2: *mzp++ = 0; \ case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \ } \ } while(0) #define malloc_COPY(dest,src,nbytes) \ do { \ INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ switch (mctmp) { \ case 0: for(;;) { *mcdst++ = *mcsrc++; \ case 7: *mcdst++ = *mcsrc++; \ case 6: *mcdst++ = *mcsrc++; \ case 5: *mcdst++ = *mcsrc++; \ case 4: *mcdst++ = *mcsrc++; \ case 3: *mcdst++ = *mcsrc++; \ case 2: *mcdst++ = *mcsrc++; \ case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \ } \ } while(0) #endif #else /* DEBUG3 */ /* The trailing moat invalidates the above prediction about the nbytes parameter to malloc_ZERO and malloc_COPY. */ #define malloc_ZERO(charp, nbytes) \ do { \ char *mzp = (char *)(charp); \ long mzn = (nbytes); \ while (mzn--) \ *mzp++ = '\0'; \ } while(0) #define malloc_COPY(dest,src,nbytes) \ do { \ char *mcsrc = (char *)(src); \ char *mcdst = (char *)(dest); \ long mcn = (nbytes); \ while (mcn--) \ *mcdst++ = *mcsrc++; \ } while(0) #endif /* DEBUG3 */ /* Define HAVE_MMAP to optionally make malloc() use mmap() to allocate very large blocks. These will be returned to the operating system immediately after a free(). */ #ifndef HAVE_MMAP #define HAVE_MMAP 1 #endif /* Define HAVE_MREMAP to make realloc() use mremap() to re-allocate large blocks. This is currently only possible on Linux with kernel versions newer than 1.3.77. */ #ifndef HAVE_MREMAP #ifdef INTERNAL_LINUX_C_LIB #define HAVE_MREMAP 1 #else #define HAVE_MREMAP 0 #endif #endif #if HAVE_MMAP #include #include #include #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) #define MAP_ANONYMOUS MAP_ANON #endif #endif /* HAVE_MMAP */ /* Access to system page size. To the extent possible, this malloc manages memory from the system in page-size units. The following mechanics for getpagesize were adapted from bsd/gnu getpagesize.h */ #ifndef LACKS_UNISTD_H # include #endif #ifndef malloc_getpagesize # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */ # ifndef _SC_PAGE_SIZE # define _SC_PAGE_SIZE _SC_PAGESIZE # endif # endif # ifdef _SC_PAGE_SIZE # define malloc_getpagesize sysconf(_SC_PAGE_SIZE) # else # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE) # if __STD_C extern size_t getpagesize(void); # else extern size_t getpagesize(); # endif # define malloc_getpagesize getpagesize() # else # include # ifdef EXEC_PAGESIZE # define malloc_getpagesize EXEC_PAGESIZE # else # ifdef NBPG # ifndef CLSIZE # define malloc_getpagesize NBPG # else # define malloc_getpagesize (NBPG * CLSIZE) # endif # else # ifdef NBPC # define malloc_getpagesize NBPC # else # ifdef PAGESIZE # define malloc_getpagesize PAGESIZE # else # define malloc_getpagesize (4096) /* just guess */ # endif # endif # endif # endif # endif # endif #endif /* This version of malloc supports the standard SVID/XPG mallinfo routine that returns a struct containing the same kind of information you can get from malloc_stats. It should work on any SVID/XPG compliant system that has a /usr/include/malloc.h defining struct mallinfo. (If you'd like to install such a thing yourself, cut out the preliminary declarations as described above and below and save them in a malloc.h file. But there's no compelling reason to bother to do this.) The main declaration needed is the mallinfo struct that is returned (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a bunch of fields, most of which are not even meaningful in this version of malloc. Some of these fields are are instead filled by mallinfo() with other numbers that might possibly 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 an SVID2/XPG2 compliant version is declared below. These must be precisely the same for mallinfo() to work. */ /* #define HAVE_USR_INCLUDE_malloc_H */ #if HAVE_USR_INCLUDE_malloc_H #include "/usr/include/malloc.h" #else /* SVID2/XPG mallinfo structure */ struct mallinfo { int arena; /* total space allocated from system */ int ordblks; /* number of non-inuse chunks */ int smblks; /* unused -- always zero */ int hblks; /* number of mmapped regions */ int hblkhd; /* total space in mmapped regions */ int usmblks; /* unused -- always zero */ int fsmblks; /* unused -- always zero */ int uordblks; /* total allocated space */ int fordblks; /* total non-inuse space */ int keepcost; /* top-most, releasable (via malloc_trim) space */ }; /* SVID2/XPG mallopt options */ #define M_MXFAST 1 /* UNUSED in this malloc */ #define M_NLBLKS 2 /* UNUSED in this malloc */ #define M_GRAIN 3 /* UNUSED in this malloc */ #define M_KEEP 4 /* UNUSED in this malloc */ #endif /* mallopt options that actually do something */ #define M_TRIM_THRESHOLD -1 #define M_TOP_PAD -2 #define M_MMAP_THRESHOLD -3 #define M_MMAP_MAX -4 #define M_SCANHEAP -5 #define M_FILL #ifndef DEFAULT_TRIM_THRESHOLD #define DEFAULT_TRIM_THRESHOLD (128 * 1024) #endif /* M_TRIM_THRESHOLD is 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. 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. The trim threshold and the mmap control parameters (see below) can be traded off with one another. Trimming and mmapping are two different ways of releasing unused memory back to the system. Between these two, it is often possible to keep system-level demands of a long-lived program down to a bare minimum. For example, in one test suite of sessions measuring the XF86 X server on Linux, using a trim threshold of 128K and a mmap threshold of 192K led to near-minimal long term resource consumption. If you are using this malloc in a long-lived program, it should pay to experiment with these values. 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's worth it to tune for trimming rather tham memory mapping 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. And in well-behaved long-lived programs, controlling release of large blocks via trimming versus mapping is usually faster. However, in most programs, these parameters serve mainly as protection against the system-level effects of carrying around massive amounts of unneeded memory. Since frequent calls to sbrk, mmap, and munmap otherwise degrade performance, the default parameters are set to relatively high values that serve only as safeguards. The default trim value is high enough to cause trimming only in fairly extreme (by current memory consumption standards) cases. It must be greater than page size to have any useful effect. To disable trimming completely, you can set to (unsigned long)(-1); */ #ifndef DEFAULT_TOP_PAD #define DEFAULT_TOP_PAD (0) #endif /* M_TOP_PAD is the amount of extra `padding' space to allocate or retain whenever sbrk is called. It is used in two ways internally: * When sbrk is called to extend the top of the arena to satisfy a new malloc request, this much padding is added to the sbrk request. * When malloc_trim is called automatically from free(), it is used as the `pad' argument. In both cases, the actual amount of padding is rounded so that the end of the arena is always a system page boundary. The main reason for using padding is to avoid calling sbrk so often. Having even a small pad greatly reduces the likelihood that nearly every malloc request during program start-up (or after trimming) will invoke sbrk, which needlessly wastes time. Automatic rounding-up to page-size units is normally sufficient to avoid measurable overhead, so the default is 0. However, in systems where sbrk is relatively slow, it can pay to increase this value, at the expense of carrying around more memory than the program needs. */ #ifndef DEFAULT_MMAP_THRESHOLD #define DEFAULT_MMAP_THRESHOLD (128 * 1024) #endif /* M_MMAP_THRESHOLD is the request size threshold for using mmap() to 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 benefit 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. Mapped memory can never become `locked' between other chunks, as can happen with normally allocated chunks, which menas that even trimming via malloc_trim would not release them. However, it has the disadvantages that: 1. The space cannot be reclaimed, consolidated, and then used to service later requests, as happens with normal chunks. 2. It can lead to more wastage because of mmap page alignment requirements 3. It causes malloc performance to be more dependent on host system memory management support routines which may vary in implementation quality and may impose arbitrary limitations. Generally, servicing a request via normal malloc steps is faster than going through a system's mmap. All together, these considerations should lead you to use mmap only for relatively large requests. */ #ifndef DEFAULT_MMAP_MAX #if HAVE_MMAP #define DEFAULT_MMAP_MAX (64) #else #define DEFAULT_MMAP_MAX (0) #endif #endif /* M_MMAP_MAX is the maximum number of requests to simultaneously service using mmap. This parameter exists because: 1. Some systems have a limited number of internal tables for use by mmap. 2. In most systems, overreliance on mmap can degrade overall performance. 3. If a program allocates many large regions, it is probably better off using normal sbrk-based allocation routines that can reclaim and reallocate normal heap memory. Using a small value allows transition into this mode after the first few allocations. Setting to 0 disables all use of mmap. If HAVE_MMAP is not set, the default value is 0, and attempts to set it to non-zero values in mallopt will fail. */ /* Special defines for linux libc Except when compiled using these special defines for Linux libc using weak aliases, this malloc is NOT designed to work in multithreaded applications. No semaphores or other concurrency control are provided to ensure that multiple malloc or free calls don't run at the same time, which could be disasterous. A single semaphore could be used across malloc, realloc, and free (which is essentially the effect of the linux weak alias approach). It would be hard to obtain finer granularity. */ #ifdef INTERNAL_LINUX_C_LIB #if __STD_C Void_t * __default_morecore_init (ptrdiff_t); Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init; #else Void_t * __default_morecore_init (); Void_t *(*__morecore)() = __default_morecore_init; #endif #define MORECORE (*__morecore) #define MORECORE_FAILURE 0 #define MORECORE_CLEARS 1 #else /* INTERNAL_LINUX_C_LIB */ #if __STD_C /* extern Void_t* sbrk(ptrdiff_t);*/ #else extern Void_t* sbrk(); #endif #ifndef MORECORE #define MORECORE sbrk #endif #ifndef MORECORE_FAILURE #define MORECORE_FAILURE -1 #endif #ifndef MORECORE_CLEARS #define MORECORE_CLEARS 0 #endif #endif /* INTERNAL_LINUX_C_LIB */ #if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__) #define cALLOc __libc_calloc #define fREe __libc_free #define mALLOc __libc_malloc #define mEMALIGn __libc_memalign #define rEALLOc __libc_realloc #define vALLOc __libc_valloc #define pvALLOc __libc_pvalloc #define mALLINFo __libc_mallinfo #define mALLOPt __libc_mallopt #pragma weak calloc = __libc_calloc #pragma weak free = __libc_free #pragma weak cfree = __libc_free #pragma weak malloc = __libc_malloc #pragma weak memalign = __libc_memalign #pragma weak realloc = __libc_realloc #pragma weak valloc = __libc_valloc #pragma weak pvalloc = __libc_pvalloc #pragma weak mallinfo = __libc_mallinfo #pragma weak mallopt = __libc_mallopt #else #ifndef cALLOc #define cALLOc dlcalloc #endif #ifndef fREe #define fREe dlfree #endif #ifndef mALLOc #define mALLOc dlmalloc #endif #ifndef mEMALIGn #define mEMALIGn dlmemalign #endif #ifndef rEALLOc #define rEALLOc dlrealloc #endif #ifndef vALLOc #define vALLOc dlvalloc #endif #ifndef pvALLOc #define pvALLOc dlpvalloc #endif #ifndef mALLINFo #define mALLINFo dlmallinfo #endif #ifndef mALLOPt #define mALLOPt dlmallopt #endif #endif /* Public routines */ #ifdef DEBUG2 #define malloc(size) malloc_dbg(size, __FILE__, __LINE__) #define free(p) free_dbg(p, __FILE__, __LINE__) #define realloc(p, size) realloc_dbg(p, size, __FILE__, __LINE__) #define calloc(n, size) calloc_dbg(n, size, __FILE__, __LINE__) #define memalign(align, size) memalign_dbg(align, size, __FILE__, __LINE__) #define valloc(size) valloc_dbg(size, __FILE__, __LINE__) #define pvalloc(size) pvalloc_dbg(size, __FILE__, __LINE__) #define malloc_trim(pad) malloc_trim_dbg(pad, __FILE__, __LINE__) #define malloc_usable_size(p) malloc_usable_size_dbg(p, __FILE__, __LINE__) #define malloc_stats(void) malloc_stats_dbg(__FILE__, __LINE__) #define mallopt(flag, val) mallopt_dbg(flag, val, __FILE__, __LINE__) #define mallinfo(void) mallinfo_dbg(__FILE__, __LINE__) #if __STD_C Void_t* malloc_dbg(size_t, const char *, int); void free_dbg(Void_t*, const char *, int); Void_t* realloc_dbg(Void_t*, size_t, const char *, int); Void_t* calloc_dbg(size_t, size_t, const char *, int); Void_t* memalign_dbg(size_t, size_t, const char *, int); Void_t* valloc_dbg(size_t, const char *, int); Void_t* pvalloc_dbg(size_t, const char *, int); int malloc_trim_dbg(size_t, const char *, int); size_t malloc_usable_size_dbg(Void_t*, const char *, int); void malloc_stats_dbg(const char *, int); int mallopt_dbg(int, int, const char *, int); struct mallinfo mallinfo_dbg(const char *, int); #else Void_t* malloc_dbg(); void free_dbg(); Void_t* realloc_dbg(); Void_t* calloc_dbg(); Void_t* memalign_dbg(); Void_t* valloc_dbg(); Void_t* pvalloc_dbg(); int malloc_trim_dbg(); size_t malloc_usable_size_dbg(); void malloc_stats_dbg(); int mallopt_dbg(); struct mallinfo mallinfo_dbg(); #endif /* !__STD_C */ #else /* !DEBUG2 */ #if __STD_C Void_t* mALLOc(size_t); void fREe(Void_t*); Void_t* rEALLOc(Void_t*, size_t); Void_t* cALLOc(size_t, size_t); Void_t* mEMALIGn(size_t, size_t); Void_t* vALLOc(size_t); Void_t* pvALLOc(size_t); int malloc_trim(size_t); size_t malloc_usable_size(Void_t*); void malloc_stats(void); int mALLOPt(int, int); struct mallinfo mALLINFo(void); #else Void_t* mALLOc(); void fREe(); Void_t* rEALLOc(); Void_t* cALLOc(); Void_t* mEMALIGn(); Void_t* vALLOc(); Void_t* pvALLOc(); int malloc_trim(); size_t malloc_usable_size(); void malloc_stats(); int mALLOPt(); struct mallinfo mALLINFo(); #endif #endif /* !DEBUG2 */ #ifdef __cplusplus }; /* end of extern "C" */ #endif /* ---------- To make a malloc.h, end cutting here ------------ */ #ifdef DEBUG2 #ifdef __cplusplus extern "C" { #endif #undef malloc #undef free #undef realloc #undef calloc #undef memalign #undef valloc #undef pvalloc #undef malloc_trim #undef malloc_usable_size #undef malloc_stats #undef mallopt #undef mallinfo #if __STD_C Void_t* mALLOc(size_t); void fREe(Void_t*); Void_t* rEALLOc(Void_t*, size_t); Void_t* cALLOc(size_t, size_t); Void_t* mEMALIGn(size_t, size_t); Void_t* vALLOc(size_t); Void_t* pvALLOc(size_t); int malloc_trim(size_t); size_t malloc_usable_size(Void_t*); void malloc_stats(void); int mALLOPt(int, int); struct mallinfo mALLINFo(void); #else Void_t* mALLOc(); void fREe(); Void_t* rEALLOc(); Void_t* cALLOc(); Void_t* mEMALIGn(); Void_t* vALLOc(); Void_t* pvALLOc(); int malloc_trim(); size_t malloc_usable_size(); void malloc_stats(); int mALLOPt(); struct mallinfo mALLINFo(); #endif #include /* isprint() */ #ifdef DEBUG3 #include /* atexit() */ #endif #ifdef __cplusplus }; /* end of extern "C" */ #endif #endif /* DEBUG2 */ /* Emulation of sbrk for WIN32 All code within the ifdef WIN32 is untested by me. */ #ifdef WIN32 #define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \ ~(malloc_getpagesize-1)) /* resrve 64MB to insure large contiguous space */ #define RESERVED_SIZE (1024*1024*64) #define NEXT_SIZE (2048*1024) #define TOP_MEMORY ((unsigned long)2*1024*1024*1024) struct GmListElement; typedef struct GmListElement GmListElement; struct GmListElement { GmListElement* next; void* base; }; static GmListElement* head = 0; static unsigned int gNextAddress = 0; static unsigned int gAddressBase = 0; static unsigned int gAllocatedSize = 0; static GmListElement* makeGmListElement (void* bas) { GmListElement* this; this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement)); ASSERT (this); if (this) { this->base = bas; this->next = head; head = this; } return this; } void gcleanup () { BOOL rval; ASSERT ( (head == NULL) || (head->base == (void*)gAddressBase)); if (gAddressBase && (gNextAddress - gAddressBase)) { rval = VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase, MEM_DECOMMIT); ASSERT (rval); } while (head) { GmListElement* next = head->next; rval = VirtualFree (head->base, 0, MEM_RELEASE); ASSERT (rval); LocalFree (head); head = next; } } static void* findRegion (void* start_address, unsigned long size) { MEMORY_BASIC_INFORMATION info; while ((unsigned long)start_address < TOP_MEMORY) { VirtualQuery (start_address, &info, sizeof (info)); if (info.State != MEM_FREE) start_address = (char*)info.BaseAddress + info.RegionSize; else if (info.RegionSize >= size) return start_address; else start_address = (char*)info.BaseAddress + info.RegionSize; } return NULL; } void* wsbrk (long size) { void* tmp; if (size > 0) { if (gAddressBase == 0) { gAllocatedSize = max (RESERVED_SIZE, AlignPage (size)); gNextAddress = gAddressBase = (unsigned int)VirtualAlloc (NULL, gAllocatedSize, MEM_RESERVE, PAGE_NOACCESS); } else if (AlignPage (gNextAddress + size) > (gAddressBase + gAllocatedSize)) { long new_size = max (NEXT_SIZE, AlignPage (size)); void* new_address = (void*)(gAddressBase+gAllocatedSize); do { new_address = findRegion (new_address, new_size); if (new_address == 0) return (void*)-1; gAddressBase = gNextAddress = (unsigned int)VirtualAlloc (new_address, new_size, MEM_RESERVE, PAGE_NOACCESS); // repeat in case of race condition // The region that we found has been snagged // by another thread } while (gAddressBase == 0); ASSERT (new_address == (void*)gAddressBase); gAllocatedSize = new_size; if (!makeGmListElement ((void*)gAddressBase)) return (void*)-1; } if ((size + gNextAddress) > AlignPage (gNextAddress)) { void* res; res = VirtualAlloc ((void*)AlignPage (gNextAddress), (size + gNextAddress - AlignPage (gNextAddress)), MEM_COMMIT, PAGE_READWRITE); if (res == 0) return (void*)-1; } tmp = (void*)gNextAddress; gNextAddress = (unsigned int)tmp + size; return tmp; } else if (size < 0) { unsigned int alignedGoal = AlignPage (gNextAddress + size); /* Trim by releasing the virtual memory */ if (alignedGoal >= gAddressBase) { VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal, MEM_DECOMMIT); gNextAddress = gNextAddress + size; return (void*)gNextAddress; } else { VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase, MEM_DECOMMIT); gNextAddress = gAddressBase; return (void*)-1; } } else { return (void*)gNextAddress; } } #endif /* Type declarations */ #ifdef DEBUG3 # define MOATWIDTH 4 /* number of guard bytes at each end of allocated region */ # define MOATFILL 5 /* moat fill character */ # define ALLOCFILL 1 /* fill char for allocated */ # define FREEFILL 2 /* and freed regions */ #endif typedef struct malloc_chunk { INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */ INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */ struct malloc_chunk* fd; /* double links -- used only if free. */ struct malloc_chunk* bk; #ifdef DEBUG3 const char *file; /* file and */ int line; /* line number of [re]allocation */ size_t pad; /* nr pad bytes at mem end, excluding moat */ int alloced; /* whether the chunk is allocated -- less prone to segv than inuse(chunk) */ char moat[MOATWIDTH]; /* actual leading moat is last MOATWIDTH bytes of chunk header; those bytes may follow this field due to header alignment padding */ #endif } Chunk; typedef Chunk* mchunkptr; /* malloc_chunk details: (The following includes lightly edited explanations by Colin Plumb.) Chunks of memory are maintained using a `boundary tag' method as described in e.g., Knuth or Standish. (See the paper by Paul Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such techniques.) Sizes of free chunks are stored both in the front of each chunk and at the end. This makes consolidating fragmented chunks into bigger chunks very fast. The size fields also hold bits representing whether chunks are free or in use. An allocated chunk looks like this: chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of previous chunk, if allocated | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of chunk, in bytes |P| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | User data starts here... . . . . (malloc_usable_space() bytes) . . | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of chunk | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where "chunk" is the front of the chunk for the purpose of most of the malloc code, but "mem" is the pointer that is returned to the user. "Nextchunk" is the beginning of the next contiguous chunk. Chunks always begin on even word boundries, so the mem portion (which is returned to the user) is also on an even word boundary, and thus double-word aligned. Free chunks are stored in circular doubly-linked lists, and look like this: chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Size of previous chunk | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ `head:' | Size of chunk, in bytes |P| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Forward pointer to next chunk in list | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Back pointer to previous chunk in list | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unused space (may be 0 bytes long) . . . . | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ `foot:' | Size of chunk, in bytes | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The P (PREV_INUSE) bit, stored in the unused low-order bit of the chunk size (which is always a multiple of two words), is an in-use bit for the *previous* chunk. If that bit is *clear*, then the word before the current chunk size contains the previous chunk size, and can be used to find the front of the previous chunk. (The very first chunk allocated always has this bit set, preventing access to non-existent (or non-owned) memory.) Note that the `foot' of the current chunk is actually represented as the prev_size of the NEXT chunk. (This makes it easier to deal with alignments etc). The two exceptions to all this are 1. The special chunk `top', which doesn't bother using the trailing size field since there is no next contiguous chunk that would have to index off it. (After initialization, `top' is forced to always exist. If it would become less than MINSIZE bytes long, it is replenished via malloc_extend_top.) 2. Chunks allocated via mmap, which have the second-lowest-order bit (IS_MMAPPED) set in their size fields. Because they are never merged or traversed from any other chunk, they have no foot size or inuse information. Available chunks are kept in any of several places (all declared below): * `av': An array of chunks serving as bin headers for consolidated chunks. Each bin is doubly linked. The bins are approximately proportionally (log) spaced. There are a lot of these bins (128). This may look excessive, but works very well in practice. All procedures maintain the invariant that no consolidated chunk physically borders another one. Chunks in bins are kept in size order, with ties going to the approximately least recently used chunk. The chunks in each bin are maintained in decreasing sorted order by size. This is irrelevant for the small bins, which all contain the same-sized chunks, but facilitates best-fit allocation for larger chunks. (These lists are just sequential. Keeping them in order almost never requires enough traversal to warrant using fancier ordered data structures.) Chunks of the same size are linked with the most recently freed at the front, and allocations are taken from the back. This results in LRU or FIFO allocation order, which tends to give each chunk an equal opportunity to be consolidated with adjacent freed chunks, resulting in larger free chunks and less fragmentation. * `top': The top-most available chunk (i.e., the one bordering the end of available memory) is treated specially. It is never included in any bin, is used only if no other chunk is available, and is released back to the system if it is very large (see M_TRIM_THRESHOLD). * `last_remainder': A bin holding only the remainder of the most recently split (non-top) chunk. This bin is checked before other non-fitting chunks, so as to provide better locality for runs of sequentially allocated chunks. * Implicitly, through the host system's memory mapping tables. If supported, requests greater than a threshold are usually serviced via calls to mmap, and then later released via munmap. */ /* sizes, alignments */ #define SIZE_SZ sizeof(INTERNAL_SIZE_T) #define ALIGNMENT (SIZE_SZ + SIZE_SZ) #define ALIGN_MASK (ALIGNMENT - 1) #ifndef DEBUG3 # define MEMOFFSET (2*SIZE_SZ) # define OVERHEAD SIZE_SZ # define MMAP_EXTRA SIZE_SZ /* for correct alignment */ # define MINSIZE sizeof(Chunk) #else typedef union { char strut[(sizeof(Chunk) - 1) / ALIGNMENT + 1][ALIGNMENT]; Chunk chunk; } PaddedChunk; # define MEMOFFSET sizeof(PaddedChunk) # define OVERHEAD (MEMOFFSET + MOATWIDTH) # define MMAP_EXTRA 0 # define MINSIZE ((OVERHEAD + ALIGN_MASK) & ~ALIGN_MASK) #endif /* conversion from malloc headers to user pointers, and back */ #define chunk2mem(p) ((Void_t*)((char*)(p) + MEMOFFSET)) #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - MEMOFFSET)) /* pad request bytes into a usable size, including overhead */ #define request2size(req) \ ((long)((req) + OVERHEAD) < (long)MINSIZE ? MINSIZE : \ ((req) + OVERHEAD + ALIGN_MASK) & ~ALIGN_MASK) /* Check if m has acceptable alignment */ #define aligned_OK(m) (((unsigned long)((m)) & ALIGN_MASK) == 0) /* Physical chunk operations */ /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */ #define PREV_INUSE 0x1 /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */ #define IS_MMAPPED 0x2 /* Bits to mask off when extracting size */ #define SIZE_BITS (PREV_INUSE|IS_MMAPPED) /* Ptr to next physical malloc_chunk. */ #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) )) /* Ptr to previous physical malloc_chunk */ #define prev_chunk(p)\ ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) )) /* Treat space at ptr + offset as a chunk */ #define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s))) /* Dealing with use bits */ /* extract p's inuse bit */ #define inuse(p)\ ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE) /* extract inuse bit of previous chunk */ #define prev_inuse(p) ((p)->size & PREV_INUSE) /* check for mmap()'ed chunk */ #if HAVE_MMAP # define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED) #else # define chunk_is_mmapped(p) 0 #endif /* set/clear chunk as in use without otherwise disturbing */ #define set_inuse(p)\ ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE #define clear_inuse(p)\ ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE) /* check/set/clear inuse bits in known places */ #define inuse_bit_at_offset(p, s)\ (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE) #define set_inuse_bit_at_offset(p, s)\ (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE) #define clear_inuse_bit_at_offset(p, s)\ (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE)) /* Dealing with size fields */ /* Get size, ignoring use bits */ #define chunksize(p) ((p)->size & ~(SIZE_BITS)) /* Set size at head, without disturbing its use bit */ #define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s))) /* Set size/use ignoring previous bits in header */ #define set_head(p, s) ((p)->size = (s)) /* Set size at footer (only when chunk is not in use) */ #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s)) /* Bins The bins, `av_' are an array of pairs of pointers serving as the heads of (initially empty) doubly-linked lists of chunks, laid out in a way so that each pair can be treated as if it were in a malloc_chunk. (This way, the fd/bk offsets for linking bin heads and chunks are the same). Bins for sizes < 512 bytes contain chunks of all the same size, spaced 8 bytes apart. Larger bins are approximately logarithmically spaced. (See the table below.) The `av_' array is never mentioned directly in the code, but instead via bin access macros. Bin layout: 64 bins of size 8 32 bins of size 64 16 bins of size 512 8 bins of size 4096 4 bins of size 32768 2 bins of size 262144 1 bin of size what's left There is actually a little bit of slop in the numbers in bin_index for the sake of speed. This makes no difference elsewhere. The special chunks `top' and `last_remainder' get their own bins, (this is implemented via yet more trickery with the av_ array), although `top' is never properly linked to its bin since it is always handled specially. */ #define NAV 128 /* number of bins */ typedef Chunk* mbinptr; /* access macros */ #define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ)) #define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr))) #define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr))) /* The first 2 bins are never indexed. The corresponding av_ cells are instead used for bookkeeping. This is not to save space, but to simplify indexing, maintain locality, and avoid some initialization tests. */ #define top (bin_at(0)->fd) /* The topmost chunk */ #define last_remainder (bin_at(1)) /* remainder from last split */ /* Because top initially points to its own bin with initial zero size, thus forcing extension on the first malloc request, we avoid having any special code in malloc to check whether it even exists yet. But we still need to in malloc_extend_top. */ #define initial_top ((mchunkptr)(bin_at(0))) /* Helper macro to initialize bins */ #define IAV(i) bin_at(i), bin_at(i) static mbinptr av_[NAV * 2 + 2] = { 0, 0, IAV(0), IAV(1), IAV(2), IAV(3), IAV(4), IAV(5), IAV(6), IAV(7), IAV(8), IAV(9), IAV(10), IAV(11), IAV(12), IAV(13), IAV(14), IAV(15), IAV(16), IAV(17), IAV(18), IAV(19), IAV(20), IAV(21), IAV(22), IAV(23), IAV(24), IAV(25), IAV(26), IAV(27), IAV(28), IAV(29), IAV(30), IAV(31), IAV(32), IAV(33), IAV(34), IAV(35), IAV(36), IAV(37), IAV(38), IAV(39), IAV(40), IAV(41), IAV(42), IAV(43), IAV(44), IAV(45), IAV(46), IAV(47), IAV(48), IAV(49), IAV(50), IAV(51), IAV(52), IAV(53), IAV(54), IAV(55), IAV(56), IAV(57), IAV(58), IAV(59), IAV(60), IAV(61), IAV(62), IAV(63), IAV(64), IAV(65), IAV(66), IAV(67), IAV(68), IAV(69), IAV(70), IAV(71), IAV(72), IAV(73), IAV(74), IAV(75), IAV(76), IAV(77), IAV(78), IAV(79), IAV(80), IAV(81), IAV(82), IAV(83), IAV(84), IAV(85), IAV(86), IAV(87), IAV(88), IAV(89), IAV(90), IAV(91), IAV(92), IAV(93), IAV(94), IAV(95), IAV(96), IAV(97), IAV(98), IAV(99), IAV(100), IAV(101), IAV(102), IAV(103), IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111), IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119), IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127) }; /* field-extraction macros */ #define first(b) ((b)->fd) #define last(b) ((b)->bk) /* Indexing into bins */ #define bin_index(sz) \ (((((unsigned long)(sz)) >> 9) == 0) ? (((unsigned long)(sz)) >> 3): \ ((((unsigned long)(sz)) >> 9) <= 4) ? 56 + (((unsigned long)(sz)) >> 6): \ ((((unsigned long)(sz)) >> 9) <= 20) ? 91 + (((unsigned long)(sz)) >> 9): \ ((((unsigned long)(sz)) >> 9) <= 84) ? 110 + (((unsigned long)(sz)) >> 12): \ ((((unsigned long)(sz)) >> 9) <= 340) ? 119 + (((unsigned long)(sz)) >> 15): \ ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \ 126) /* bins for chunks < 512 are all spaced 8 bytes apart, and hold identically sized chunks. This is exploited in malloc. */ #define MAX_SMALLBIN 63 #define MAX_SMALLBIN_SIZE 512 #define SMALLBIN_WIDTH 8 #define smallbin_index(sz) (((unsigned long)(sz)) >> 3) /* Requests are `small' if both the corresponding and the next bin are small */ #define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH) /* To help compensate for the large number of bins, a one-level index structure is used for bin-by-bin searching. `binblocks' is a one-word bitvector recording whether groups of BINBLOCKWIDTH bins have any (possibly) non-empty bins, so they can be skipped over all at once during during traversals. The bits are NOT always cleared as soon as all bins in a block are empty, but instead only when all are noticed to be empty during traversal in malloc. */ #define BINBLOCKWIDTH 4 /* bins per block */ #define binblocks (bin_at(0)->size) /* bitvector of nonempty blocks */ /* bin<->block macros */ #define idx2binblock(ix) ((unsigned)1 << (ix / BINBLOCKWIDTH)) #define mark_binblock(ii) (binblocks |= idx2binblock(ii)) #define clear_binblock(ii) (binblocks &= ~(idx2binblock(ii))) /* Other static bookkeeping data */ /* variables holding tunable values */ static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD; static unsigned long top_pad = DEFAULT_TOP_PAD; static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX; static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD; #ifdef DEBUG2 static int scanheap = 1; #endif /* The first value returned from sbrk */ static char* sbrk_base = (char*)(-1); /* The maximum memory obtained from system via sbrk */ static unsigned long max_sbrked_mem = 0; /* The maximum via either sbrk or mmap */ static unsigned long max_total_mem = 0; /* internal working copy of mallinfo */ static struct mallinfo current_mallinfo = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; /* The total memory obtained from system via sbrk */ #define sbrked_mem (current_mallinfo.arena) /* Tracking mmaps */ static unsigned int n_mmaps = 0; static unsigned long mmapped_mem = 0; #if HAVE_MMAP static unsigned int max_n_mmaps = 0; static unsigned long max_mmapped_mem = 0; #endif /* Debugging support */ #if DEBUG #ifndef DEBUG2 # define unless(cond, err, p) assert(cond) #else # define unless(cond, err, p) do { if (!(cond)) malloc_err(err, p); } while (0) /* * When debug_file is non-null, it and debug_line respectively contain the * file and line number of the current invocation of malloc(), calloc(), * realloc(), or free(). */ static const char *debug_file = NULL; static int debug_line; /* * Avoid dereferencing invalid chunk.file pointers by tracking the range of * valid ones. Could add an "unallocated" flag to init_freed_chunk() for * more protection, but that's probably not necessary. */ static const char *debug_file_min = (char *)~0; static const char *debug_file_max = NULL; static char *itos(int n) { #define NDIGITS (sizeof(int) * 3) static char s[NDIGITS + 1]; int i = NDIGITS; do { s[--i] = '0' + n % 10; n /= 10; } while (n); return s + i; #undef NDIGITS } static int recurs = 0; static void errprint(const char *file, int line, const char *err) { if (recurs++) { recurs--; return; } if (file) { write(2, file, strlen(file)); if (line) { write(2, ":", 1); write(2, itos(line), strlen(itos(line))); } write(2, ": ", 2); } write(2, err, strlen(err)); write(2, "\n", 1); recurs--; } static void malloc_err(const char *err, mchunkptr p) { /* * Display ERR on stderr, accompanying it with the caller's file and line * number if available. If P is non-null, also attempt to display the file * and line number at which P was most recently [re]allocated. * * This function's name begins with "malloc_" to make setting debugger * breakpoints here more convenient. */ errprint(debug_file, debug_line, err); # ifndef DEBUG3 p = 0; /* avoid "unused param" warning */ # else if (p && p->file && /* avoid invalid pointers */ debug_file_min && p->file >= debug_file_min && p->file <= debug_file_max) errprint(p->file, p->line, "in block allocated here"); # endif } #undef malloc #undef free #undef realloc #undef memalign #undef valloc #undef pvalloc #undef calloc #undef malloc_trim #undef malloc_usable_size #undef malloc_stats #undef mallopt #undef mallinfo static void malloc_update_mallinfo(void); /* * Define front-end functions for all user-visible entry points that may * trigger error(). */ #define skel(retdecl, retassign, call, retstmt) \ retdecl \ debug_file = file; \ debug_line = line; \ if (debug_file < debug_file_min) \ debug_file_min = debug_file; \ if (debug_file > debug_file_max) \ debug_file_max = debug_file; \ if (scanheap) \ malloc_update_mallinfo(); \ retassign call; \ if (scanheap) \ malloc_update_mallinfo(); \ debug_file = NULL; \ retstmt /* * The final letter of the names of the following macros is either r or v, * indicating that the macro handles functions with or without a return value, * respectively. */ # define skelr(rettype, call) \ skel(rettype ret;, ret = , call, return ret) /* * AIX's xlc compiler doesn't like empty macro args, so specify useless but * compilable retdecl, retassign, and retstmt args: */ #define skelv(call) \ skel(line += 0;, if (1), call, return) #define dbgargs const char *file, int line /* * Front-end function definitions: */ Void_t* malloc_dbg(size_t bytes, dbgargs) { skelr(Void_t*, malloc(bytes)); } void free_dbg(Void_t *mem, dbgargs) { skelv(free(mem)); } Void_t* realloc_dbg(Void_t *oldmem, size_t bytes, dbgargs) { skelr(Void_t*, realloc(oldmem, bytes)); } Void_t* memalign_dbg(size_t alignment, size_t bytes, dbgargs) { skelr(Void_t*, dlmemalign(alignment, bytes)); } Void_t* valloc_dbg(size_t bytes, dbgargs) { skelr(Void_t*, dlvalloc(bytes)); } Void_t* pvalloc_dbg(size_t bytes, dbgargs) { skelr(Void_t*, dlpvalloc(bytes)); } Void_t* calloc_dbg(size_t n, size_t elem_size, dbgargs) { skelr(Void_t*, calloc(n, elem_size)); } int malloc_trim_dbg(size_t pad, dbgargs) { skelr(int, malloc_trim(pad)); } size_t malloc_usable_size_dbg(Void_t *mem, dbgargs) { skelr(size_t, malloc_usable_size(mem)); } void malloc_stats_dbg(dbgargs) { skelv(malloc_stats()); } int mallopt_dbg(int flag, int value, dbgargs) { skelr(int, dlmallopt(flag, value)); } struct mallinfo mallinfo_dbg(dbgargs) { skelr(struct mallinfo, dlmallinfo()); } #undef skel #undef skelr #undef skelv #undef dbgargs #endif /* DEBUG2 */ /* These routines make a number of assertions about the states of data structures that should be true at all times. If any are not true, it's very likely that a user program has somehow trashed memory. (It's also possible that there is a coding error in malloc. In which case, please report it!) */ #ifdef DEBUG3 static int memtest(void *s, int c, size_t n) { /* * Return whether the N-byte memory region starting at S consists * entirely of bytes with value C. */ unsigned char *p = (unsigned char *)s; size_t i; for (i = 0; i < n; i++) if (p[i] != (unsigned char)c) return 0; return 1; } #endif /* DEBUG3 */ #ifndef DEBUG3 #define check_moats(P) #else #define check_moats do_check_moats static void do_check_moats(mchunkptr p) { INTERNAL_SIZE_T sz = chunksize(p); unless(memtest((char *)chunk2mem(p) - MOATWIDTH, MOATFILL, MOATWIDTH), "region underflow", p); unless(memtest((char *)p + sz - MOATWIDTH - p->pad, MOATFILL, MOATWIDTH + p->pad), "region overflow", p); } #endif /* DEBUG3 */ #if __STD_C static void do_check_chunk(mchunkptr p) #else static void do_check_chunk(p) mchunkptr p; #endif { /* Try to ensure legal addresses before accessing any chunk fields, in the * hope of issuing an informative message rather than causing a segv. * * The following chunk_is_mmapped() call accesses p->size #if HAVE_MMAP. * This is unavoidable without maintaining a record of mmapped regions. */ if (!chunk_is_mmapped(p)) { INTERNAL_SIZE_T sz; unless((char*)p >= sbrk_base, "chunk precedes sbrk_base", p); unless((char*)p + MINSIZE <= (char*)top + chunksize(top), "chunk past sbrk area", p); sz = chunksize(p); if (p != top) unless((char*)p + sz <= (char*)top, "chunk extends beyond top", p); else unless((char*)p + sz <= sbrk_base + sbrked_mem, "chunk extends past sbrk area", p); } check_moats(p); } #if __STD_C static void do_check_free_chunk(mchunkptr p) #else static void do_check_free_chunk(p) mchunkptr p; #endif { INTERNAL_SIZE_T sz = chunksize(p); mchunkptr next = chunk_at_offset(p, sz); do_check_chunk(p); /* Check whether it claims to be free ... */ unless(!inuse(p), "free chunk marked inuse", p); /* Unless a special marker, must have OK fields */ if ((long)sz >= (long)MINSIZE) { unless((sz & ALIGN_MASK) == 0, "freed size defies alignment", p); unless(aligned_OK(chunk2mem(p)), "misaligned freed region", p); /* ... matching footer field */ unless(next->prev_size == sz, "chunk size mismatch", p); /* ... and is fully consolidated */ unless(prev_inuse(p), "free chunk not joined with prev", p); unless(next == top || inuse(next), "free chunk not joined with next", p); /* ... and has minimally sane links */ unless(p->fd->bk == p, "broken forward link", p); unless(p->bk->fd == p, "broken backward link", p); } else /* markers are always of size SIZE_SZ */ unless(sz == SIZE_SZ, "invalid small chunk size", p); } #if __STD_C static void do_check_inuse_chunk(mchunkptr p) #else static void do_check_inuse_chunk(p) mchunkptr p; #endif { mchunkptr next; do_check_chunk(p); if (chunk_is_mmapped(p)) return; /* Check whether it claims to be in use ... */ #ifdef DEBUG3 unless(p->alloced, "memory not allocated", p); #endif unless(inuse(p), "memory not allocated", p); /* ... and is surrounded by OK chunks. Since more things can be checked with free chunks than inuse ones, if an inuse chunk borders them and debug is on, it's worth doing them. */ if (!prev_inuse(p)) { mchunkptr prv = prev_chunk(p); unless(next_chunk(prv) == p, "prev link scrambled", p); do_check_free_chunk(prv); } next = next_chunk(p); if (next == top) { unless(prev_inuse(next), "top chunk wrongly thinks prev is unused", p); unless(chunksize(next) >= MINSIZE, "top chunk too small", p); } else if (!inuse(next)) do_check_free_chunk(next); } #if __STD_C static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s) #else static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s; #endif { INTERNAL_SIZE_T sz = chunksize(p); long room = sz - s; do_check_inuse_chunk(p); /* Legal size ... */ unless((long)sz >= (long)MINSIZE, "chunk size too small", p); unless((sz & ALIGN_MASK) == 0, "malloced size defies alignment", p); unless(room >= 0, "chunk size too small for contents", p); unless(room < (long)MINSIZE, "chunk size leaves too much spare room", p); /* ... and alignment */ unless(aligned_OK(chunk2mem(p)), "misaligned malloced region", p); /* ... and was allocated at front of an available chunk */ unless(prev_inuse(p), "malloced from the middle of a free chunk", p); } #ifdef DEBUG3 static void init_alloced_chunk(mchunkptr p, size_t bytes) { Void_t* mem = chunk2mem(p); p->file = debug_file; p->line = debug_line; p->pad = chunksize(p) - OVERHEAD - bytes; p->alloced = 1; memset((char *)mem + bytes, MOATFILL, p->pad + MOATWIDTH); } static void do_init_malloced_chunk(mchunkptr p, size_t bytes) { Void_t* mem = chunk2mem(p); init_alloced_chunk(p, bytes); memset((char *)mem - MOATWIDTH, MOATFILL, MOATWIDTH); memset(mem, ALLOCFILL, bytes); } static void do_init_realloced_chunk(mchunkptr p, size_t bytes, INTERNAL_SIZE_T oldsize) { Void_t* mem = chunk2mem(p); INTERNAL_SIZE_T newsize = chunksize(p); init_alloced_chunk(p, bytes); if (oldsize < newsize) /* This incorrectly leaves the leading pad area of the old trailing moat * set to MOATFILL rather than ALLOCFILL. An alternative is to save the * old p->pad in rEALLOc() below and pass it to this function. */ memset((char *)mem + oldsize - OVERHEAD, ALLOCFILL, bytes - (oldsize - OVERHEAD)); } static void do_check_freefill(mchunkptr p, long newsize, INTERNAL_SIZE_T oldsize) { /* The first newsize bytes of oldsize-byte chunk p are about to be * allocated. Issue a warning if any freefill locations in p that are about * to be overwritten do not contain the character FREEFILL. */ size_t bytes, maxbytes; if (newsize <= 0) return; bytes = newsize - MEMOFFSET /* don't check p's header */ + MEMOFFSET; /* header of split-off remainder */ maxbytes = oldsize - OVERHEAD; if (bytes > maxbytes) bytes = maxbytes; unless(memtest(chunk2mem(p), FREEFILL, bytes), "detected write to freed region", p); } static void do_init_freed_chunk(mchunkptr p, INTERNAL_SIZE_T freehead, INTERNAL_SIZE_T freetail) { /* freehead and freetail are the number of bytes at the beginning of p and * end of p respectively that should already be initialized as free regions. */ Void_t* mem = chunk2mem(p); size_t size = chunksize(p); size_t bytes = size - OVERHEAD; p->pad = 0; p->alloced = 0; memset((char *)mem - MOATWIDTH, MOATFILL, MOATWIDTH); memset((char *)mem + bytes, MOATFILL, MOATWIDTH); /* To avoid terrible O(n^2) performance when free() repeatedly grows a free * chunk, it's important not to free-fill regions that are already * free-filled. */ if (freehead + freetail < size) { Void_t* start = !freehead ? mem : (char *)p + freehead - MOATWIDTH; size_t len = (char *)p + size - (char *)start - (!freetail ? MOATWIDTH : freetail - OVERHEAD); memset(start, FREEFILL, len); } } static void do_init_freeable_chunk(mchunkptr p) { /* Arrange for the subsequent fREe(p) not to generate any warnings. */ init_alloced_chunk(p, chunksize(p) - OVERHEAD); memset((char *)chunk2mem(p) - MOATWIDTH, MOATFILL, MOATWIDTH); } static void do_maximize_chunk(mchunkptr p) { if (p->pad) { Void_t* mem = chunk2mem(p); size_t bytes = chunksize(p) - OVERHEAD - p->pad; memset((char *)mem + bytes, ALLOCFILL, p->pad); p->pad = 0; } } static int do_check_init(void) { /* Called from the first invocation of malloc_extend_top(), as detected by * sbrk_base == -1. Return whether this function allocated any memory. */ static int state = 0; /* 1 => initializing, 2 => initialized */ if (state == 1) return 0; unless(state == 0, "multiple calls to check_init", NULL); state++; atexit(malloc_update_mallinfo); /* calls malloc on WinNT */ return sbrk_base != (char *)-1; } #endif /* DEBUG3 */ static mchunkptr lowest_chunk; #define check_free_chunk(P) do_check_free_chunk(P) #define check_inuse_chunk(P) do_check_inuse_chunk(P) #define check_chunk(P) do_check_chunk(P) #define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N) #else /* !DEBUG */ #define check_free_chunk(P) #define check_inuse_chunk(P) #define check_chunk(P) #define check_malloced_chunk(P,N) #endif /* !DEBUG */ #ifdef DEBUG3 #define check_init do_check_init #define init_malloced_chunk do_init_malloced_chunk #define init_realloced_chunk do_init_realloced_chunk #define check_freefill do_check_freefill #define init_freed_chunk do_init_freed_chunk #define init_freeable_chunk do_init_freeable_chunk #define maximize_chunk do_maximize_chunk #else #define check_init() 0 #define init_malloced_chunk(P,B) #define init_realloced_chunk(P,B,O) #define check_freefill(P,N,O) #define init_freed_chunk(P,H,T) #define init_freeable_chunk(P) #define maximize_chunk(P) #endif /* !DEBUG3 */ /* Macro-based internal utilities */ /* Linking chunks in bin lists. Call these only with variables, not arbitrary expressions, as arguments. */ /* Place chunk p of size s in its bin, in size order, putting it ahead of others of same size. */ #define frontlink(P, S, IDX, BK, FD) \ { \ if (S < MAX_SMALLBIN_SIZE) \ { \ IDX = smallbin_index(S); \ mark_binblock(IDX); \ BK = bin_at(IDX); \ FD = BK->fd; \ P->bk = BK; \ P->fd = FD; \ FD->bk = BK->fd = P; \ } \ else \ { \ IDX = bin_index(S); \ BK = bin_at(IDX); \ FD = BK->fd; \ if (FD == BK) mark_binblock(IDX); \ else \ { \ while (FD != BK && S < chunksize(FD)) FD = FD->fd; \ BK = FD->bk; \ } \ P->bk = BK; \ P->fd = FD; \ FD->bk = BK->fd = P; \ } \ } /* take a chunk off a list */ #define unlink(P, BK, FD) \ { \ BK = P->bk; \ FD = P->fd; \ FD->bk = BK; \ BK->fd = FD; \ } \ /* Place p as the last remainder */ #define link_last_remainder(P) \ { \ last_remainder->fd = last_remainder->bk = P; \ P->fd = P->bk = last_remainder; \ } /* Clear the last_remainder bin */ #define clear_last_remainder \ (last_remainder->fd = last_remainder->bk = last_remainder) /* Routines dealing with mmap(). */ #if HAVE_MMAP #if __STD_C static mchunkptr mmap_chunk(size_t size) #else static mchunkptr mmap_chunk(size) size_t size; #endif { size_t page_mask = malloc_getpagesize - 1; mchunkptr p; #ifndef MAP_ANONYMOUS static int fd = -1; #endif if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */ size = (size + MMAP_EXTRA + page_mask) & ~page_mask; #ifdef MAP_ANONYMOUS p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); #else /* !MAP_ANONYMOUS */ if (fd < 0) { fd = open("/dev/zero", O_RDWR); if(fd < 0) return 0; } p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); #endif if(p == (mchunkptr)-1) return 0; n_mmaps++; if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps; /* We demand that eight bytes into a page must be 8-byte aligned. */ assert(aligned_OK(chunk2mem(p))); /* The offset to the start of the mmapped region is stored * in the prev_size field of the chunk; normally it is zero, * but that can be changed in memalign(). */ p->prev_size = 0; set_head(p, size|IS_MMAPPED); mmapped_mem += size; if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) max_mmapped_mem = mmapped_mem; if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) max_total_mem = mmapped_mem + sbrked_mem; return p; } #if __STD_C static void munmap_chunk(mchunkptr p) #else static void munmap_chunk(p) mchunkptr p; #endif { INTERNAL_SIZE_T size = chunksize(p); int ret; assert (chunk_is_mmapped(p)); assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); assert((n_mmaps > 0)); assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0); n_mmaps--; mmapped_mem -= (size + p->prev_size); ret = munmap((char *)p - p->prev_size, size + p->prev_size); /* munmap returns non-zero on failure */ assert(ret == 0); } #if HAVE_MREMAP #if __STD_C static mchunkptr mremap_chunk(mchunkptr p, size_t new_size) #else static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size; #endif { size_t page_mask = malloc_getpagesize - 1; INTERNAL_SIZE_T offset = p->prev_size; INTERNAL_SIZE_T size = chunksize(p); char *cp; assert (chunk_is_mmapped(p)); assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); assert((n_mmaps > 0)); assert(((size + offset) & (malloc_getpagesize-1)) == 0); new_size = (new_size + offset + MMAP_EXTRA + page_mask) & ~page_mask; cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1); if (cp == (char *)-1) return 0; p = (mchunkptr)(cp + offset); assert(aligned_OK(chunk2mem(p))); assert(p->prev_size == offset); set_head(p, (new_size - offset)|IS_MMAPPED); mmapped_mem -= size + offset; mmapped_mem += new_size; if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) max_mmapped_mem = mmapped_mem; if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) max_total_mem = mmapped_mem + sbrked_mem; return p; } #endif /* HAVE_MREMAP */ #endif /* HAVE_MMAP */ /* Extend the top-most chunk by obtaining memory from system. Main interface to sbrk (but see also malloc_trim). */ #if __STD_C static void malloc_extend_top(INTERNAL_SIZE_T nb) #else static void malloc_extend_top(nb) INTERNAL_SIZE_T nb; #endif { char* lim; /* return value from sbrk */ INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */ INTERNAL_SIZE_T correction; /* bytes for 2nd sbrk call */ char* new_lim; /* return of 2nd sbrk call */ INTERNAL_SIZE_T top_size; /* new size of top chunk */ mchunkptr old_top = top; /* Record state of old top */ INTERNAL_SIZE_T old_top_size = chunksize(old_top); char* old_end = (char*)(chunk_at_offset(old_top, old_top_size)); /* Pad request with top_pad plus minimal overhead */ INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE; unsigned long pagesz = malloc_getpagesize; /* If not the first time through, round to preserve page boundary */ /* Otherwise, we need to correct to a page size below anyway. */ /* (We also correct below if an intervening foreign sbrk call.) */ if (sbrk_base != (char*)(-1)) sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1); else if (check_init()) { if (chunksize(top) - nb < (long)MINSIZE) malloc_extend_top(nb); return; } lim = (char*)(MORECORE (sbrk_size)); /* Fail if sbrk failed or if a foreign sbrk call killed our space */ if (lim == (char*)(MORECORE_FAILURE) || (lim < old_end && old_top != initial_top)) return; sbrked_mem += sbrk_size; if (lim == old_end) /* can just add bytes to current top */ { top_size = sbrk_size + old_top_size; set_head(top, top_size | PREV_INUSE); } else { #ifdef SBRKDBG INTERNAL_SIZE_T padding = (char *)sbrk (0) - (lim + sbrk_size); sbrk_size += padding; sbrked_mem += padding; #endif if (sbrk_base == (char*)(-1)) /* First time through. Record base */ sbrk_base = lim; else /* Someone else called sbrk(). Count those bytes as sbrked_mem. */ sbrked_mem += lim - (char*)old_end; /* Guarantee alignment of first new chunk made from this space */ front_misalign = (unsigned long)chunk2mem(lim) & ALIGN_MASK; if (front_misalign > 0) { correction = (ALIGNMENT) - front_misalign; lim += correction; } else correction = 0; /* Guarantee the next brk will be at a page boundary */ correction += pagesz - ((unsigned long)(lim + sbrk_size) & (pagesz - 1)); /* Allocate correction */ new_lim = (char*)(MORECORE (correction)); if (new_lim == (char*)(MORECORE_FAILURE)) return; sbrked_mem += correction; top = (mchunkptr)lim; top_size = new_lim - lim + correction; set_head(top, top_size | PREV_INUSE); #if DEBUG lowest_chunk = top; #endif #ifdef OTHER_SBRKS if (old_top != initial_top) { /* There must have been an intervening foreign sbrk call. */ /* A double fencepost is necessary to prevent consolidation */ /* If not enough space to do this, then user did something very wrong */ if (old_top_size < MINSIZE) { set_head(top, PREV_INUSE); /* will force null return from malloc */ return; } old_top_size -= 2*SIZE_SZ; chunk_at_offset(old_top, old_top_size )->size = SIZE_SZ|PREV_INUSE; chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size = SIZE_SZ|PREV_INUSE; set_head_size(old_top, old_top_size); /* If possible, release the rest. */ if (old_top_size >= MINSIZE) { init_freeable_chunk(old_top); fREe(chunk2mem(old_top)); } } #endif /* OTHER_SBRKS */ } init_freed_chunk(top, old_top == initial_top ? old_top_size : 0, 0); if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem) max_sbrked_mem = sbrked_mem; if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) max_total_mem = mmapped_mem + sbrked_mem; /* We always land on a page boundary */ assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0); } /* Main public routines */ /* Malloc Algorthim: The requested size is first converted into a usable form, `nb'. This currently means to add 4 bytes overhead plus possibly more to obtain 8-byte alignment and/or to obtain a size of at least MINSIZE (currently 16 bytes), the smallest allocatable size. (All fits are considered `exact' if they are within MINSIZE bytes.) From there, the first successful of the following steps is taken: 1. The bin corresponding to the request size is scanned, and if a chunk of exactly the right size is found, it is taken. 2. The most recently remaindered chunk is used if it is big enough. This is a form of (roving) first fit, used only in the absence of exact fits. Runs of consecutive requests use the remainder of the chunk used for the previous such request whenever possible. This limited use of a first-fit style allocation strategy tends to give contiguous chunks coextensive lifetimes, which improves locality and can reduce fragmentation in the long run. 3. Other bins are scanned in increasing size order, using a chunk big enough to fulfill the request, and splitting off any remainder. This search is strictly by best-fit; i.e., the smallest (with ties going to approximately the least recently used) chunk that fits is selected. 4. If large enough, the chunk bordering the end of memory (`top') is split off. (This use of `top' is in accord with the best-fit search rule. In effect, `top' is treated as larger (and thus less well fitting) than any other available chunk since it can be extended to be as large as necessary (up to system limitations). 5. If the request size meets the mmap threshold and the system supports mmap, and there are few enough currently allocated mmapped regions, and a call to mmap succeeds, the request is allocated via direct memory mapping. 6. Otherwise, the top of memory is extended by obtaining more space from the system (normally using sbrk, but definable to anything else via the MORECORE macro). Memory is gathered from the system (in system page-sized units) in a way that allows chunks obtained across different sbrk calls to be consolidated, but does not require contiguous memory. Thus, it should be safe to intersperse mallocs with other sbrk calls. All allocations are made from the the `lowest' part of any found chunk. (The implementation invariant is that prev_inuse is always true of any allocated chunk; i.e., that each allocated chunk borders either a previously allocated and still in-use chunk, or the base of its memory arena.) */ #if __STD_C Void_t* mALLOc(size_t bytes) #else Void_t* mALLOc(bytes) size_t bytes; #endif { mchunkptr victim; /* inspected/selected chunk */ INTERNAL_SIZE_T victim_size; /* its size */ int idx; /* index for bin traversal */ mbinptr bin; /* associated bin */ mchunkptr remainder; /* remainder from a split */ long remainder_size; /* its size */ int remainder_index; /* its bin index */ unsigned long block; /* block traverser bit */ int startidx; /* first bin of a traversed block */ mchunkptr fwd; /* misc temp for linking */ mchunkptr bck; /* misc temp for linking */ mbinptr q; /* misc temp */ INTERNAL_SIZE_T nb = request2size(bytes); /* padded request size; */ /* Check for exact match in a bin */ if (is_small_request(nb)) /* Faster version for small requests */ { idx = smallbin_index(nb); /* No traversal or size check necessary for small bins. */ q = bin_at(idx); victim = last(q); /* Also scan the next one, since it would have a remainder < MINSIZE */ if (victim == q) { q = next_bin(q); victim = last(q); } if (victim != q) { victim_size = chunksize(victim); unlink(victim, bck, fwd); set_inuse_bit_at_offset(victim, victim_size); check_freefill(victim, victim_size, victim_size); init_malloced_chunk(victim, bytes); check_malloced_chunk(victim, nb); return chunk2mem(victim); } idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */ } else { idx = bin_index(nb); bin = bin_at(idx); for (victim = last(bin); victim != bin; victim = victim->bk) { victim_size = chunksize(victim); remainder_size = victim_size - nb; if (remainder_size >= (long)MINSIZE) /* too big */ { --idx; /* adjust to rescan below after checking last remainder */ break; } else if (remainder_size >= 0) /* exact fit */ { unlink(victim, bck, fwd); set_inuse_bit_at_offset(victim, victim_size); check_freefill(victim, victim_size, victim_size); init_malloced_chunk(victim, bytes); check_malloced_chunk(victim, nb); return chunk2mem(victim); } } ++idx; } /* Try to use the last split-off remainder */ if ( (victim = last_remainder->fd) != last_remainder) { victim_size = chunksize(victim); remainder_size = victim_size - nb; if (remainder_size >= (long)MINSIZE) /* re-split */ { remainder = chunk_at_offset(victim, nb); set_head(victim, nb | PREV_INUSE); check_freefill(victim, nb, victim_size); init_malloced_chunk(victim, bytes); link_last_remainder(remainder); set_head(remainder, remainder_size | PREV_INUSE); set_foot(remainder, remainder_size); init_freed_chunk(remainder, remainder_size, 0); check_malloced_chunk(victim, nb); return chunk2mem(victim); } clear_last_remainder; if (remainder_size >= 0) /* exhaust */ { set_inuse_bit_at_offset(victim, victim_size); check_freefill(victim, victim_size, victim_size); init_malloced_chunk(victim, bytes); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* Else place in bin */ frontlink(victim, victim_size, remainder_index, bck, fwd); } /* If there are any possibly nonempty big-enough blocks, search for best fitting chunk by scanning bins in blockwidth units. */ if ( (block = idx2binblock(idx)) <= binblocks) { /* Get to the first marked block */ if ( (block & binblocks) == 0) { /* force to an even block boundary */ idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH; block <<= 1; while ((block & binblocks) == 0) { idx += BINBLOCKWIDTH; block <<= 1; } } /* For each possibly nonempty block ... */ for (;;) { startidx = idx; /* (track incomplete blocks) */ q = bin = bin_at(idx); /* For each bin in this block ... */ do { /* Find and use first big enough chunk ... */ for (victim = last(bin); victim != bin; victim = victim->bk) { victim_size = chunksize(victim); remainder_size = victim_size - nb; if (remainder_size >= (long)MINSIZE) /* split */ { remainder = chunk_at_offset(victim, nb); set_head(victim, nb | PREV_INUSE); check_freefill(victim, nb, victim_size); unlink(victim, bck, fwd); init_malloced_chunk(victim, bytes); link_last_remainder(remainder); set_head(remainder, remainder_size | PREV_INUSE); set_foot(remainder, remainder_size); init_freed_chunk(remainder, remainder_size, 0); check_malloced_chunk(victim, nb); return chunk2mem(victim); } else if (remainder_size >= 0) /* take */ { check_freefill(victim, victim_size, victim_size); set_inuse_bit_at_offset(victim, victim_size); unlink(victim, bck, fwd); init_malloced_chunk(victim, bytes); check_malloced_chunk(victim, nb); return chunk2mem(victim); } } bin = next_bin(bin); } while ((++idx & (BINBLOCKWIDTH - 1)) != 0); /* Clear out the block bit. */ do /* Possibly backtrack to try to clear a partial block */ { if ((startidx & (BINBLOCKWIDTH - 1)) == 0) { binblocks &= ~block; break; } --startidx; q = prev_bin(q); } while (first(q) == q); /* Get to the next possibly nonempty block */ if ( (block <<= 1) <= binblocks && (block != 0) ) { while ((block & binblocks) == 0) { idx += BINBLOCKWIDTH; block <<= 1; } } else break; } } /* Try to use top chunk */ /* Require that there be a remainder, ensuring top always exists */ if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE) { #if HAVE_MMAP /* If big and would otherwise need to extend, try to use mmap instead */ if ((unsigned long)nb >= (unsigned long)mmap_threshold && (victim = mmap_chunk(nb)) != 0) { init_malloced_chunk(victim, bytes); return chunk2mem(victim); } #endif /* Try to extend */ malloc_extend_top(nb); if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE) return 0; /* propagate failure */ } victim = top; set_head(victim, nb | PREV_INUSE); check_freefill(victim, nb, nb + remainder_size); init_malloced_chunk(victim, bytes); top = chunk_at_offset(victim, nb); set_head(top, remainder_size | PREV_INUSE); init_freed_chunk(top, remainder_size, 0); check_malloced_chunk(victim, nb); return chunk2mem(victim); } /* free() algorithm : cases: 1. free(0) has no effect. 2. If the chunk was allocated via mmap, it is release via munmap(). 3. If a returned chunk borders the current high end of memory, it is consolidated into the top, and if the total unused topmost memory exceeds the trim threshold, malloc_trim is called. 4. Other chunks are consolidated as they arrive, and placed in corresponding bins. (This includes the case of consolidating with the current `last_remainder'). */ #if __STD_C void fREe(Void_t* mem) #else void fREe(mem) Void_t* mem; #endif { mchunkptr p; /* chunk corresponding to mem */ INTERNAL_SIZE_T hd; /* its head field */ INTERNAL_SIZE_T sz; /* its size */ int idx; /* its bin index */ mchunkptr next; /* next contiguous chunk */ INTERNAL_SIZE_T nextsz; /* its size */ INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */ mchunkptr bck; /* misc temp for linking */ mchunkptr fwd; /* misc temp for linking */ int islr; /* track whether merging with last_remainder */ if (mem == 0) /* free(0) has no effect */ return; p = mem2chunk(mem); check_inuse_chunk(p); hd = p->size; #if HAVE_MMAP if (hd & IS_MMAPPED) /* release mmapped memory. */ { munmap_chunk(p); return; } #endif sz = hd & ~PREV_INUSE; next = chunk_at_offset(p, sz); nextsz = chunksize(next); prevsz = 0; /* avoid compiler warnings */ if (next == top) /* merge with top */ { sz += nextsz; if (!(hd & PREV_INUSE)) /* consolidate backward */ { prevsz = p->prev_size; p = chunk_at_offset(p, -(long)prevsz); sz += prevsz; unlink(p, bck, fwd); } set_head(p, sz | PREV_INUSE); top = p; init_freed_chunk(top, !(hd & PREV_INUSE) ? prevsz : 0, nextsz); if ((unsigned long)(sz) >= trim_threshold) malloc_trim(top_pad); return; } set_head(next, nextsz); /* clear inuse bit */ islr = 0; if (!(hd & PREV_INUSE)) /* consolidate backward */ { prevsz = p->prev_size; p = chunk_at_offset(p, -(long)prevsz); sz += prevsz; if (p->fd == last_remainder) /* keep as last_remainder */ islr = 1; else unlink(p, bck, fwd); } if (!(inuse_bit_at_offset(next, nextsz))) /* consolidate forward */ { sz += nextsz; if (!islr && next->fd == last_remainder) /* re-insert last_remainder */ { islr = 1; link_last_remainder(p); } else unlink(next, bck, fwd); } set_head(p, sz | PREV_INUSE); set_foot(p, sz); if (!islr) frontlink(p, sz, idx, bck, fwd); init_freed_chunk(p, !(hd & PREV_INUSE) ? prevsz : 0, !inuse_bit_at_offset(next, nextsz) ? nextsz : 0); } /* Realloc algorithm: Chunks that were obtained via mmap cannot be extended or shrunk unless HAVE_MREMAP is defined, in which case mremap is used. Otherwise, if their reallocation is for additional space, they are copied. If for less, they are just left alone. Otherwise, if the reallocation is for additional space, and the chunk can be extended, it is, else a malloc-copy-free sequence is taken. There are several different ways that a chunk could be extended. All are tried: * Extending forward into following adjacent free chunk. * Shifting backwards, joining preceding adjacent space * Both shifting backwards and extending forward. * Extending into newly sbrked space Unless the #define realloc_ZERO_BYTES_FREES is set, realloc with a size argument of zero (re)allocates a minimum-sized chunk. If the reallocation is for less space, and the new request is for a `small' (<512 bytes) size, then the newly unused space is lopped off and freed. The old unix realloc convention of allowing the last-free'd chunk to be used as an argument to realloc is no longer supported. I don't know of any programs still relying on this feature, and allowing it would also allow too many other incorrect usages of realloc to be sensible. */ #if __STD_C Void_t* rEALLOc(Void_t* oldmem, size_t bytes) #else Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes; #endif { INTERNAL_SIZE_T nb; /* padded request size */ mchunkptr oldp; /* chunk corresponding to oldmem */ INTERNAL_SIZE_T oldsize; /* its size */ mchunkptr newp; /* chunk to return */ INTERNAL_SIZE_T newsize; /* its size */ Void_t* newmem; /* corresponding user mem */ mchunkptr next; /* next contiguous chunk after oldp */ INTERNAL_SIZE_T nextsize; /* its size */ mchunkptr prev; /* previous contiguous chunk before oldp */ INTERNAL_SIZE_T prevsize; /* its size */ mchunkptr remainder; /* holds split off extra space from newp */ INTERNAL_SIZE_T remainder_size; /* its size */ mchunkptr bck; /* misc temp for linking */ mchunkptr fwd; /* misc temp for linking */ #ifdef realloc_ZERO_BYTES_FREES if (bytes == 0) { fREe(oldmem); return 0; } #endif /* realloc of null is supposed to be same as malloc */ if (oldmem == 0) return mALLOc(bytes); newp = oldp = mem2chunk(oldmem); newsize = oldsize = chunksize(oldp); nb = request2size(bytes); check_inuse_chunk(oldp); #if HAVE_MMAP if (chunk_is_mmapped(oldp)) { if (oldsize - MMAP_EXTRA >= nb) { init_realloced_chunk(oldp, bytes, oldsize); return oldmem; /* do nothing */ } #if HAVE_MREMAP newp = mremap_chunk(oldp, nb); if (newp) { init_realloced_chunk(newp, bytes, oldsize); return chunk2mem(newp); } #endif /* Must alloc, copy, free. */ newmem = mALLOc(bytes); if (newmem == 0) return 0; /* propagate failure */ malloc_COPY(newmem, oldmem, oldsize - OVERHEAD - MMAP_EXTRA); munmap_chunk(oldp); return newmem; } #endif if (oldsize < nb) { /* Try expanding forward */ next = chunk_at_offset(oldp, oldsize); if (next == top || !inuse(next)) { nextsize = chunksize(next); /* Forward into top only if a remainder */ if (next == top) { if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE)) { check_freefill(next, nb - oldsize, nextsize); newsize += nextsize; top = chunk_at_offset(oldp, nb); set_head(top, (newsize - nb) | PREV_INUSE); init_freed_chunk(top, newsize - nb, 0); set_head_size(oldp, nb); init_realloced_chunk(oldp, bytes, oldsize); return chunk2mem(oldp); } } /* Forward into next chunk */ else if (((long)(nextsize + newsize) >= (long)nb)) { check_freefill(next, nb - oldsize, nextsize); unlink(next, bck, fwd); newsize += nextsize; goto split; } } else { next = 0; nextsize = 0; } /* Try shifting backwards. */ if (!prev_inuse(oldp)) { prev = prev_chunk(oldp); prevsize = chunksize(prev); /* try forward + backward first to save a later consolidation */ if (next != 0) { /* into top */ if (next == top) { if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE)) { check_freefill(prev, nb, prevsize); check_freefill(next, nb - (prevsize + newsize), nextsize); unlink(prev, bck, fwd); newp = prev; newsize += prevsize + nextsize; newmem = chunk2mem(newp); malloc_COPY(newmem, oldmem, oldsize - OVERHEAD); top = chunk_at_offset(newp, nb); set_head(top, (newsize - nb) | PREV_INUSE); init_freed_chunk(top, newsize - nb, 0); set_head_size(newp, nb); init_realloced_chunk(newp, bytes, oldsize); return newmem; } } /* into next chunk */ else if (((long)(nextsize + prevsize + newsize) >= (long)(nb))) { check_freefill(prev, nb, prevsize); check_freefill(next, nb - (prevsize + newsize), nextsize); unlink(next, bck, fwd); unlink(prev, bck, fwd); newp = prev; newsize += nextsize + prevsize; newmem = chunk2mem(newp); malloc_COPY(newmem, oldmem, oldsize - OVERHEAD); goto split; } } /* backward only */ if (prev != 0 && (long)(prevsize + newsize) >= (long)nb) { check_freefill(prev, nb, prevsize); unlink(prev, bck, fwd); newp = prev; newsize += prevsize; newmem = chunk2mem(newp); malloc_COPY(newmem, oldmem, oldsize - OVERHEAD); goto split; } } /* Must allocate */ newmem = mALLOc (bytes); if (newmem == 0) /* propagate failure */ return 0; /* Avoid copy if newp is next chunk after oldp. */ /* (This can only happen when new chunk is sbrk'ed.) */ if ( (newp = mem2chunk(newmem)) == next_chunk(oldp)) { newsize += chunksize(newp); newp = oldp; goto split; } /* Otherwise copy, free, and exit */ malloc_COPY(newmem, oldmem, oldsize - OVERHEAD); fREe(oldmem); return newmem; } split: /* split off extra room in old or expanded chunk */ if (newsize - nb >= MINSIZE) /* split off remainder */ { remainder = chunk_at_offset(newp, nb); remainder_size = newsize - nb; set_head_size(newp, nb); set_head(remainder, remainder_size | PREV_INUSE); set_inuse_bit_at_offset(remainder, remainder_size); init_malloced_chunk(remainder, remainder_size - OVERHEAD); fREe(chunk2mem(remainder)); /* let free() deal with it */ } else { set_head_size(newp, newsize); set_inuse_bit_at_offset(newp, newsize); } init_realloced_chunk(newp, bytes, oldsize); check_inuse_chunk(newp); return chunk2mem(newp); } /* memalign algorithm: memalign requests more than enough space from malloc, finds a spot within that chunk that meets the alignment request, and then possibly frees the leading and trailing space. The alignment argument must be a power of two. This property is not checked by memalign, so misuse may result in random runtime errors. 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. */ #if __STD_C Void_t* mEMALIGn(size_t alignment, size_t bytes) #else Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes; #endif { INTERNAL_SIZE_T nb; /* padded request size */ char* m; /* memory returned by malloc call */ mchunkptr p; /* corresponding chunk */ char* lim; /* alignment point within p */ mchunkptr newp; /* chunk to return */ INTERNAL_SIZE_T newsize; /* its size */ INTERNAL_SIZE_T leadsize; /* leading space befor alignment point */ mchunkptr remainder; /* spare room at end to split off */ long remainder_size; /* its size */ /* If need less alignment than we give anyway, just relay to malloc */ if (alignment <= ALIGNMENT) return mALLOc(bytes); /* Otherwise, ensure that it is at least a minimum chunk size */ if (alignment < MINSIZE) alignment = MINSIZE; /* Call malloc with worst case padding to hit alignment. */ nb = request2size(bytes); m = (char*)mALLOc(nb + alignment + MINSIZE); if (m == 0) return 0; /* propagate failure */ p = mem2chunk(m); if ((((unsigned long)(m)) % alignment) == 0) /* aligned */ { init_realloced_chunk(p, bytes, chunksize(p)); return chunk2mem(p); /* nothing more to do */ } else /* misaligned */ { /* Find an aligned spot inside chunk. Since we need to give back leading space in a chunk of at least MINSIZE, if the first calculation places us at a spot with less than MINSIZE leader, we can move to the next aligned spot -- we've allocated enough total room so that this is always possible. */ lim = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & ~(alignment - 1)); if ((lim - (char*)p) < (long)MINSIZE) lim = lim + alignment; newp = (mchunkptr)lim; leadsize = lim - (char*)p; newsize = chunksize(p) - leadsize; #if HAVE_MMAP if(chunk_is_mmapped(p)) { newp->prev_size = p->prev_size + leadsize; set_head(newp, newsize|IS_MMAPPED); init_malloced_chunk(newp, bytes); return chunk2mem(newp); } #endif /* give back leader, use the rest */ set_head(newp, newsize | PREV_INUSE); set_inuse_bit_at_offset(newp, newsize); set_head_size(p, leadsize); init_freeable_chunk(p); fREe(chunk2mem(p)); p = newp; assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0); } /* Also give back spare room at the end */ remainder_size = chunksize(p) - nb; if (remainder_size >= (long)MINSIZE) { remainder = chunk_at_offset(p, nb); set_head(remainder, remainder_size | PREV_INUSE); set_head_size(p, nb); init_freeable_chunk(remainder); fREe(chunk2mem(remainder)); } init_malloced_chunk(p, bytes); check_inuse_chunk(p); return chunk2mem(p); } /* valloc just invokes memalign with alignment argument equal to the page size of the system (or as near to this as can be figured out from all the includes/defines above.) */ #if __STD_C Void_t* vALLOc(size_t bytes) #else Void_t* vALLOc(bytes) size_t bytes; #endif { return mEMALIGn (malloc_getpagesize, bytes); } /* pvalloc just invokes valloc for the nearest pagesize that will accommodate request */ #if __STD_C Void_t* pvALLOc(size_t bytes) #else Void_t* pvALLOc(bytes) size_t bytes; #endif { size_t pagesize = malloc_getpagesize; return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1)); } /* calloc calls malloc, then zeroes out the allocated chunk. */ #if __STD_C Void_t* cALLOc(size_t n, size_t elem_size) #else Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size; #endif { mchunkptr p; INTERNAL_SIZE_T csz; INTERNAL_SIZE_T sz = n * elem_size; /* check if expand_top called, in which case don't need to clear */ #if MORECORE_CLEARS mchunkptr oldtop = top; INTERNAL_SIZE_T oldtopsize = chunksize(top); #endif Void_t* mem = mALLOc (sz); if (mem == 0) return 0; else { p = mem2chunk(mem); /* Two optional cases in which clearing not necessary */ #if HAVE_MMAP if (chunk_is_mmapped(p)) return mem; #endif csz = chunksize(p); #if MORECORE_CLEARS if (p == oldtop && csz > oldtopsize) { /* clear only the bytes from non-freshly-sbrked memory */ csz = oldtopsize; } #endif malloc_ZERO(mem, csz - OVERHEAD); /* reinstate moat fill in pad region */ init_realloced_chunk(p, sz, chunksize(p)); return mem; } } /* Malloc_trim gives memory back to the system (via negative arguments to sbrk) if there is unused memory at the `high' end of the malloc pool. 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 (one page or less). 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. */ #if __STD_C int dlmalloc_trim(size_t pad) #else int malloc_trim(pad) size_t pad; #endif { long top_size; /* Amount of top-most memory */ long extra; /* Amount to release */ char* current_lim; /* address returned by pre-check sbrk call */ char* new_lim; /* address returned by negative sbrk call */ unsigned long pagesz = malloc_getpagesize; top_size = chunksize(top); extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz; if (extra < (long)pagesz) /* Not enough memory to release */ return 0; else { #ifdef OTHER_SBRKS /* Test to make sure no one else called sbrk */ current_lim = (char*)(MORECORE (0)); if (current_lim != (char*)(top) + top_size) return 0; /* Apparently we don't own memory; must fail */ else #endif { new_lim = (char*)(MORECORE (-extra)); if (new_lim == (char*)(MORECORE_FAILURE)) /* sbrk failed? */ { /* Try to figure out what we have */ current_lim = (char*)(MORECORE (0)); top_size = current_lim - (char*)top; if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */ { sbrked_mem = current_lim - sbrk_base; set_head(top, top_size | PREV_INUSE); init_freed_chunk(top, top_size, 0); } check_chunk(top); return 0; } else { /* Success. Adjust top accordingly. */ set_head(top, (top_size - extra) | PREV_INUSE); sbrked_mem -= extra; init_freed_chunk(top, top_size - extra, 0); check_chunk(top); return 1; } } } } /* malloc_usable_size: This routine tells you how many bytes you can actually use in an allocated chunk, which may be more than you requested (although often not). You can use this many bytes without worrying about overwriting other allocated objects. Not a particularly great programming practice, but still sometimes useful. */ #if __STD_C size_t dlmalloc_usable_size(Void_t* mem) #else size_t malloc_usable_size(mem) Void_t* mem; #endif { mchunkptr p; if (mem == 0) return 0; else { p = mem2chunk(mem); check_inuse_chunk(p); maximize_chunk(p); if(!chunk_is_mmapped(p)) { if (!inuse(p)) return 0; return chunksize(p) - OVERHEAD; } return chunksize(p) - OVERHEAD - MMAP_EXTRA; } } /* Utility to update current_mallinfo for malloc_stats and mallinfo() */ static void malloc_update_mallinfo(void) { int i; mbinptr b; mchunkptr p; #if DEBUG mchunkptr q; #endif INTERNAL_SIZE_T avail = chunksize(top); int navail = avail >= MINSIZE ? 1 : 0; check_freefill(top, avail, avail); #if DEBUG if (lowest_chunk) for (p = lowest_chunk; p < top && inuse(p) && chunksize(p) >= MINSIZE; p = next_chunk(p)) check_inuse_chunk(p); #endif for (i = 1; i < NAV; ++i) { b = bin_at(i); for (p = last(b); p != b; p = p->bk) { #if DEBUG check_free_chunk(p); check_freefill(p, chunksize(p), chunksize(p)); for (q = next_chunk(p); q < top && inuse(q) && chunksize(q) >= MINSIZE; q = next_chunk(q)) check_inuse_chunk(q); #endif avail += chunksize(p); navail++; } } current_mallinfo.ordblks = navail; current_mallinfo.uordblks = sbrked_mem - avail; current_mallinfo.fordblks = avail; current_mallinfo.hblks = n_mmaps; current_mallinfo.hblkhd = mmapped_mem; current_mallinfo.keepcost = chunksize(top); } /* malloc_stats: Prints on stderr the amount of space obtain 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), the maximum number of simultaneous mmap regions used, 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.) */ void dlmalloc_stats(void) { malloc_update_mallinfo(); fprintf(stderr, "max system bytes = %10u\n", (unsigned int)(max_total_mem)); fprintf(stderr, "system bytes = %10u\n", (unsigned int)(sbrked_mem + mmapped_mem)); fprintf(stderr, "in use bytes = %10u\n", (unsigned int)(current_mallinfo.uordblks + mmapped_mem)); #if HAVE_MMAP fprintf(stderr, "max mmap regions = %10u\n", (unsigned int)max_n_mmaps); #endif } /* mallinfo returns a copy of updated current mallinfo. */ struct mallinfo mALLINFo(void) { malloc_update_mallinfo(); return current_mallinfo; } /* mallopt: mallopt is the general SVID/XPG interface to 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. See descriptions of tunable parameters above. */ #if __STD_C int mALLOPt(int param_number, int value) #else int mALLOPt(param_number, value) int param_number; int value; #endif { switch(param_number) { case M_TRIM_THRESHOLD: trim_threshold = value; return 1; case M_TOP_PAD: top_pad = value; return 1; case M_MMAP_THRESHOLD: mmap_threshold = value; return 1; case M_MMAP_MAX: #if HAVE_MMAP n_mmaps_max = value; return 1; #else if (value != 0) return 0; else n_mmaps_max = value; return 1; #endif case M_SCANHEAP: #ifdef DEBUG2 scanheap = value; #endif return 1; default: return 0; } } /* History: V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee) * Added pvalloc, as recommended by H.J. Liu * Added 64bit pointer support mainly from Wolfram Gloger * Added anonymously donated WIN32 sbrk emulation * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen * malloc_extend_top: fix mask error that caused wastage after foreign sbrks * Add linux mremap support code from HJ Liu V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee) * Integrated most documentation with the code. * Add support for mmap, with help from Wolfram Gloger (Gloger@lrz.uni-muenchen.de). * Use last_remainder in more cases. * Pack bins using idea from colin@nyx10.cs.du.edu * Use ordered bins instead of best-fit threshhold * Eliminate block-local decls to simplify tracing and debugging. * Support another case of realloc via move into top * Fix error occuring when initial sbrk_base not word-aligned. * Rely on page size for units instead of SBRK_UNIT to avoid surprises about sbrk alignment conventions. * Add mallinfo, mallopt. Thanks to Raymond Nijssen (raymond@es.ele.tue.nl) for the suggestion. * Add `pad' argument to malloc_trim and top_pad mallopt parameter. * More precautions for cases where other routines call sbrk, courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de). * Added macros etc., allowing use in linux libc from H.J. Lu (hjl@gnu.ai.mit.edu) * Inverted this history list V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee) * Re-tuned and fixed to behave more nicely with V2.6.0 changes. * Removed all preallocation code since under current scheme the work required to undo bad preallocations exceeds the work saved in good cases for most test programs. * No longer use return list or unconsolidated bins since no scheme using them consistently outperforms those that don't given above changes. * Use best fit for very large chunks to prevent some worst-cases. * Added some support for debugging V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee) * Removed footers when chunks are in use. Thanks to Paul Wilson (wilson@cs.texas.edu) for the suggestion. V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee) * Added malloc_trim, with help from Wolfram Gloger (wmglo@Dent.MED.Uni-Muenchen.DE). V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g) V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g) * realloc: try to expand in both directions * malloc: swap order of clean-bin strategy; * realloc: only conditionally expand backwards * Try not to scavenge used bins * Use bin counts as a guide to preallocation * Occasionally bin return list chunks in first scan * Add a few optimizations from colin@nyx10.cs.du.edu V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g) * faster bin computation & slightly different binning * merged all consolidations to one part of malloc proper (eliminating old malloc_find_space & malloc_clean_bin) * Scan 2 returns chunks (not just 1) * Propagate failure in realloc if malloc returns 0 * Add stuff to allow compilation on non-ANSI compilers from kpv@research.att.com V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu) * removed potential for odd address access in prev_chunk * removed dependency on getpagesize.h * misc cosmetics and a bit more internal documentation * anticosmetics: mangled names in macros to evade debugger strangeness * tested on sparc, hp-700, dec-mips, rs6000 with gcc & native cc (hp, dec only) allowing Detlefs & Zorn comparison study (in SIGPLAN Notices.) Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu) * Based loosely on libg++-1.2X malloc. (It retains some of the overall structure of old version, but most details differ.) */