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authorwdenk <wdenk>2002-10-25 20:35:49 +0000
committerwdenk <wdenk>2002-10-25 20:35:49 +0000
commit217c9dad827c91a7ac168a8eaacf0e17af7608b9 (patch)
tree07a002742d97f8005a63ff95fff55e266d6ad2f1 /common/dlmalloc.c
parentce23b153d8aa8c235ea59c78b12bd7f1aa3cc57b (diff)
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+#if 0 /* Moved to malloc.h */
+/* ---------- 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 2.6.6 Sun Mar 5 19:10:03 2000 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.
+ 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 when the request
+ size is treaded as a long will return null.
+
+ 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 if not WIN32)
+ Define this if your system does not have a <unistd.h>.
+ LACKS_SYS_PARAM_H (default: undefined if not WIN32)
+ Define this if your system does not have a <sys/param.h>.
+ 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 1)
+ 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.
+ USE_DL_PREFIX (default: undefined)
+ Prefix all public routines with the string 'dl'. Useful to
+ quickly avoid procedure declaration conflicts and linker symbol
+ conflicts with existing memory allocation routines.
+
+
+*/
+
+
+
+
+/* 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 || defined(WIN32))
+#define Void_t void
+#else
+#define Void_t char
+#endif
+#endif /*Void_t*/
+
+#if __STD_C
+#include <stddef.h> /* for size_t */
+#else
+#include <sys/types.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdio.h> /* needed for malloc_stats */
+
+
+/*
+ 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 DEBUG
+#include <assert.h>
+#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
+
+#define LACKS_UNISTD_H
+#define LACKS_SYS_PARAM_H
+
+/*
+ Include 'windows.h' to get the necessary declarations for the
+ Microsoft Visual C++ data structures and routines used in the 'sbrk'
+ emulation.
+
+ Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft
+ Visual C++ header files are included.
+*/
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#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
+#ifdef WIN32
+// On Win32 platforms, 'memset()' and 'memcpy()' are already declared in
+// 'windows.h'
+#else
+Void_t* memset();
+Void_t* memcpy();
+#endif
+#endif
+#endif
+
+#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
+
+
+/*
+ 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 <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#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 <unistd.h>
+#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)
+ extern size_t getpagesize();
+# define malloc_getpagesize getpagesize()
+# else
+# ifdef WIN32
+# define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */
+# else
+# ifndef LACKS_SYS_PARAM_H
+# include <sys/param.h>
+# endif
+# 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
+#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
+
+
+
+#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.
+*/
+
+
+
+
+/*
+ USE_DL_PREFIX will prefix all public routines with the string 'dl'.
+ Useful to quickly avoid procedure declaration conflicts and linker
+ symbol conflicts with existing memory allocation routines.
+
+*/
+
+/* #define USE_DL_PREFIX */
+
+
+
+
+/*
+
+ 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 1
+#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
+
+#ifdef USE_DL_PREFIX
+#define cALLOc dlcalloc
+#define fREe dlfree
+#define mALLOc dlmalloc
+#define mEMALIGn dlmemalign
+#define rEALLOc dlrealloc
+#define vALLOc dlvalloc
+#define pvALLOc dlpvalloc
+#define mALLINFo dlmallinfo
+#define mALLOPt dlmallopt
+#else /* USE_DL_PREFIX */
+#define cALLOc calloc
+#define fREe free
+#define mALLOc malloc
+#define mEMALIGn memalign
+#define rEALLOc realloc
+#define vALLOc valloc
+#define pvALLOc pvalloc
+#define mALLINFo mallinfo
+#define mALLOPt mallopt
+#endif /* USE_DL_PREFIX */
+
+#endif
+
+/* Public routines */
+
+#if __STD_C
+
+Void_t* mALLOc(size_t);
+void fREe(Void_t*);
+Void_t* rEALLOc(Void_t*, size_t);
+Void_t* mEMALIGn(size_t, size_t);
+Void_t* vALLOc(size_t);
+Void_t* pvALLOc(size_t);
+Void_t* cALLOc(size_t, size_t);
+void cfree(Void_t*);
+int malloc_trim(size_t);
+size_t malloc_usable_size(Void_t*);
+void malloc_stats();
+int mALLOPt(int, int);
+struct mallinfo mALLINFo(void);
+#else
+Void_t* mALLOc();
+void fREe();
+Void_t* rEALLOc();
+Void_t* mEMALIGn();
+Void_t* vALLOc();
+Void_t* pvALLOc();
+Void_t* cALLOc();
+void cfree();
+int malloc_trim();
+size_t malloc_usable_size();
+void malloc_stats();
+int mALLOPt();
+struct mallinfo mALLINFo();
+#endif
+
+
+#ifdef __cplusplus
+}; /* end of extern "C" */
+#endif
+
+/* ---------- To make a malloc.h, end cutting here ------------ */
+#else /* Moved to malloc.h */
+
+#include <malloc.h>
+#if 0
+#if __STD_C
+static void malloc_update_mallinfo (void);
+void malloc_stats (void);
+#else
+static void malloc_update_mallinfo ();
+void malloc_stats();
+#endif
+#endif /* 0 */
+
+#endif /* 0 */ /* Moved to malloc.h */
+#include <common.h>
+
+/*
+ Emulation of sbrk for WIN32
+ All code within the ifdef WIN32 is untested by me.
+
+ Thanks to Martin Fong and others for supplying this.
+*/
+
+
+#ifdef WIN32
+
+#define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \
+~(malloc_getpagesize-1))
+#define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 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;
+ if (size >= TOP_MEMORY) return NULL;
+
+ while ((unsigned long)start_address + size < TOP_MEMORY)
+ {
+ VirtualQuery (start_address, &info, sizeof (info));
+ if ((info.State == MEM_FREE) && (info.RegionSize >= size))
+ return start_address;
+ else
+ {
+ // Requested region is not available so see if the
+ // next region is available. Set 'start_address'
+ // to the next region and call 'VirtualQuery()'
+ // again.
+
+ start_address = (char*)info.BaseAddress + info.RegionSize;
+
+ // Make sure we start looking for the next region
+ // on the *next* 64K boundary. Otherwise, even if
+ // the new region is free according to
+ // 'VirtualQuery()', the subsequent call to
+ // 'VirtualAlloc()' (which follows the call to
+ // this routine in 'wsbrk()') will round *down*
+ // the requested address to a 64K boundary which
+ // we already know is an address in the
+ // unavailable region. Thus, the subsequent call
+ // to 'VirtualAlloc()' will fail and bring us back
+ // here, causing us to go into an infinite loop.
+
+ start_address =
+ (void *) AlignPage64K((unsigned long) start_address);
+ }
+ }
+ 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
+*/
+
+
+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;
+};
+
+typedef struct malloc_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 MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ)
+#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
+#define MINSIZE (sizeof(struct malloc_chunk))
+
+/* conversion from malloc headers to user pointers, and back */
+
+#define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ))
+#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ))
+
+/* pad request bytes into a usable size */
+
+#define request2size(req) \
+ (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
+ (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
+ (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
+
+/* Check if m has acceptable alignment */
+
+#define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_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 */
+
+#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)
+
+/* 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 struct malloc_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)
+};
+
+void malloc_bin_reloc (void)
+{
+ DECLARE_GLOBAL_DATA_PTR;
+
+ unsigned long *p = (unsigned long *)(&av_[2]);
+ int i;
+ for (i=2; i<(sizeof(av_)/sizeof(mbinptr)); ++i) {
+ *p++ += gd->reloc_off;
+ }
+}
+
+
+/* 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;
+
+/* 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 */
+
+#if 0
+static unsigned int n_mmaps = 0;
+#endif /* 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
+*/
+
+#ifdef DEBUG
+
+
+/*
+ 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!)
+*/
+
+#if __STD_C
+static void do_check_chunk(mchunkptr p)
+#else
+static void do_check_chunk(p) mchunkptr p;
+#endif
+{
+#if 0 /* causes warnings because assert() is off */
+ INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
+#endif /* 0 */
+
+ /* No checkable chunk is mmapped */
+ assert(!chunk_is_mmapped(p));
+
+ /* Check for legal address ... */
+ assert((char*)p >= sbrk_base);
+ if (p != top)
+ assert((char*)p + sz <= (char*)top);
+ else
+ assert((char*)p + sz <= sbrk_base + sbrked_mem);
+
+}
+
+
+#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 = p->size & ~PREV_INUSE;
+#if 0 /* causes warnings because assert() is off */
+ mchunkptr next = chunk_at_offset(p, sz);
+#endif /* 0 */
+
+ do_check_chunk(p);
+
+ /* Check whether it claims to be free ... */
+ assert(!inuse(p));
+
+ /* Unless a special marker, must have OK fields */
+ if ((long)sz >= (long)MINSIZE)
+ {
+ assert((sz & MALLOC_ALIGN_MASK) == 0);
+ assert(aligned_OK(chunk2mem(p)));
+ /* ... matching footer field */
+ assert(next->prev_size == sz);
+ /* ... and is fully consolidated */
+ assert(prev_inuse(p));
+ assert (next == top || inuse(next));
+
+ /* ... and has minimally sane links */
+ assert(p->fd->bk == p);
+ assert(p->bk->fd == p);
+ }
+ else /* markers are always of size SIZE_SZ */
+ assert(sz == SIZE_SZ);
+}
+
+#if __STD_C
+static void do_check_inuse_chunk(mchunkptr p)
+#else
+static void do_check_inuse_chunk(p) mchunkptr p;
+#endif
+{
+ mchunkptr next = next_chunk(p);
+ do_check_chunk(p);
+
+ /* Check whether it claims to be in use ... */
+ assert(inuse(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);
+ assert(next_chunk(prv) == p);
+ do_check_free_chunk(prv);
+ }
+ if (next == top)
+ {
+ assert(prev_inuse(next));
+ assert(chunksize(next) >= MINSIZE);
+ }
+ 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
+{
+#if 0 /* causes warnings because assert() is off */
+ INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
+ long room = sz - s;
+#endif /* 0 */
+
+ do_check_inuse_chunk(p);
+
+ /* Legal size ... */
+ assert((long)sz >= (long)MINSIZE);
+ assert((sz & MALLOC_ALIGN_MASK) == 0);
+ assert(room >= 0);
+ assert(room < (long)MINSIZE);
+
+ /* ... and alignment */
+ assert(aligned_OK(chunk2mem(p)));
+
+
+ /* ... and was allocated at front of an available chunk */
+ assert(prev_inuse(p));
+
+}
+
+
+#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
+#define check_free_chunk(P)
+#define check_inuse_chunk(P)
+#define check_chunk(P)
+#define check_malloced_chunk(P,N)
+#endif
+
+
+
+/*
+ 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 */
+
+ /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because
+ * there is no following chunk whose prev_size field could be used.
+ */
+ size = (size + SIZE_SZ + 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);
+
+ /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */
+ new_size = (new_size + offset + SIZE_SZ + 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* brk; /* 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_brk; /* 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);
+
+ brk = (char*)(MORECORE (sbrk_size));
+
+ /* Fail if sbrk failed or if a foreign sbrk call killed our space */
+ if (brk == (char*)(MORECORE_FAILURE) ||
+ (brk < old_end && old_top != initial_top))
+ return;
+
+ sbrked_mem += sbrk_size;
+
+ if (brk == old_end) /* can just add bytes to current top */
+ {
+ top_size = sbrk_size + old_top_size;
+ set_head(top, top_size | PREV_INUSE);
+ }
+ else
+ {
+ if (sbrk_base == (char*)(-1)) /* First time through. Record base */
+ sbrk_base = brk;
+ else /* Someone else called sbrk(). Count those bytes as sbrked_mem. */
+ sbrked_mem += brk - (char*)old_end;
+
+ /* Guarantee alignment of first new chunk made from this space */
+ front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK;
+ if (front_misalign > 0)
+ {
+ correction = (MALLOC_ALIGNMENT) - front_misalign;
+ brk += correction;
+ }
+ else
+ correction = 0;
+
+ /* Guarantee the next brk will be at a page boundary */
+
+ correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) &
+ ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size));
+
+ /* Allocate correction */
+ new_brk = (char*)(MORECORE (correction));
+ if (new_brk == (char*)(MORECORE_FAILURE)) return;
+
+ sbrked_mem += correction;
+
+ top = (mchunkptr)brk;
+ top_size = new_brk - brk + correction;
+ set_head(top, top_size | PREV_INUSE);
+
+ 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;
+ }
+
+ /* Also keep size a multiple of MALLOC_ALIGNMENT */
+ old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK;
+ set_head_size(old_top, old_top_size);
+ 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;
+ /* If possible, release the rest. */
+ if (old_top_size >= MINSIZE)
+ fREe(chunk2mem(old_top));
+ }
+ }
+
+ 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;
+
+ if ((long)bytes < 0) return 0;
+
+ 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_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_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);
+ link_last_remainder(remainder);
+ set_head(remainder, remainder_size | PREV_INUSE);
+ set_foot(remainder, remainder_size);
+ 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_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);
+ unlink(victim, bck, fwd);
+ link_last_remainder(remainder);
+ set_head(remainder, remainder_size | PREV_INUSE);
+ set_foot(remainder, remainder_size);
+ check_malloced_chunk(victim, nb);
+ return chunk2mem(victim);
+ }
+
+ else if (remainder_size >= 0) /* take */
+ {
+ set_inuse_bit_at_offset(victim, victim_size);
+ unlink(victim, bck, fwd);
+ 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)
+ 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);
+ top = chunk_at_offset(victim, nb);
+ set_head(top, remainder_size | PREV_INUSE);
+ 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);
+ hd = p->size;
+
+#if HAVE_MMAP
+ if (hd & IS_MMAPPED) /* release mmapped memory. */
+ {
+ munmap_chunk(p);
+ return;
+ }
+#endif
+
+ check_inuse_chunk(p);
+
+ sz = hd & ~PREV_INUSE;
+ next = chunk_at_offset(p, sz);
+ nextsz = chunksize(next);
+
+ 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;
+ if ((unsigned long)(sz) >= (unsigned long)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);
+}
+
+
+
+
+
+/*
+
+ 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
+
+ if ((long)bytes < 0) return 0;
+
+ /* 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);
+
+#if HAVE_MMAP
+ if (chunk_is_mmapped(oldp))
+ {
+#if HAVE_MREMAP
+ newp = mremap_chunk(oldp, nb);
+ if(newp) return chunk2mem(newp);
+#endif
+ /* Note the extra SIZE_SZ overhead. */
+ if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */
+ /* Must alloc, copy, free. */
+ newmem = mALLOc(bytes);
+ if (newmem == 0) return 0; /* propagate failure */
+ MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ);
+ munmap_chunk(oldp);
+ return newmem;
+ }
+#endif
+
+ check_inuse_chunk(oldp);
+
+ if ((long)(oldsize) < (long)(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))
+ {
+ newsize += nextsize;
+ top = chunk_at_offset(oldp, nb);
+ set_head(top, (newsize - nb) | PREV_INUSE);
+ set_head_size(oldp, nb);
+ return chunk2mem(oldp);
+ }
+ }
+
+ /* Forward into next chunk */
+ else if (((long)(nextsize + newsize) >= (long)(nb)))
+ {
+ 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))
+ {
+ unlink(prev, bck, fwd);
+ newp = prev;
+ newsize += prevsize + nextsize;
+ newmem = chunk2mem(newp);
+ MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
+ top = chunk_at_offset(newp, nb);
+ set_head(top, (newsize - nb) | PREV_INUSE);
+ set_head_size(newp, nb);
+ return newmem;
+ }
+ }
+
+ /* into next chunk */
+ else if (((long)(nextsize + prevsize + newsize) >= (long)(nb)))
+ {
+ unlink(next, bck, fwd);
+ unlink(prev, bck, fwd);
+ newp = prev;
+ newsize += nextsize + prevsize;
+ newmem = chunk2mem(newp);
+ MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
+ goto split;
+ }
+ }
+
+ /* backward only */
+ if (prev != 0 && (long)(prevsize + newsize) >= (long)nb)
+ {
+ unlink(prev, bck, fwd);
+ newp = prev;
+ newsize += prevsize;
+ newmem = chunk2mem(newp);
+ MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ);
+ 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 - SIZE_SZ);
+ 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);
+ fREe(chunk2mem(remainder)); /* let free() deal with it */
+ }
+ else
+ {
+ set_head_size(newp, newsize);
+ set_inuse_bit_at_offset(newp, newsize);
+ }
+
+ 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* brk; /* 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 ((long)bytes < 0) return 0;
+
+ /* If need less alignment than we give anyway, just relay to malloc */
+
+ if (alignment <= MALLOC_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 */
+ {
+#if HAVE_MMAP
+ if(chunk_is_mmapped(p))
+ return chunk2mem(p); /* nothing more to do */
+#endif
+ }
+ 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.
+ */
+
+ brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment));
+ if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment;
+
+ newp = (mchunkptr)brk;
+ leadsize = brk - (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);
+ 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);
+ 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);
+ fREe(chunk2mem(remainder));
+ }
+
+ 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 ((long)n < 0) return 0;
+
+ 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 - SIZE_SZ);
+ return mem;
+ }
+}
+
+/*
+
+ cfree just calls free. It is needed/defined on some systems
+ that pair it with calloc, presumably for odd historical reasons.
+
+*/
+
+#if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__)
+#if __STD_C
+void cfree(Void_t *mem)
+#else
+void cfree(mem) Void_t *mem;
+#endif
+{
+ fREe(mem);
+}
+#endif
+
+
+
+/*
+
+ 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 malloc_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_brk; /* address returned by pre-check sbrk call */
+ char* new_brk; /* 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
+ {
+ /* Test to make sure no one else called sbrk */
+ current_brk = (char*)(MORECORE (0));
+ if (current_brk != (char*)(top) + top_size)
+ return 0; /* Apparently we don't own memory; must fail */
+
+ else
+ {
+ new_brk = (char*)(MORECORE (-extra));
+
+ if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */
+ {
+ /* Try to figure out what we have */
+ current_brk = (char*)(MORECORE (0));
+ top_size = current_brk - (char*)top;
+ if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */
+ {
+ sbrked_mem = current_brk - sbrk_base;
+ set_head(top, top_size | PREV_INUSE);
+ }
+ check_chunk(top);
+ return 0;
+ }
+
+ else
+ {
+ /* Success. Adjust top accordingly. */
+ set_head(top, (top_size - extra) | PREV_INUSE);
+ sbrked_mem -= extra;
+ 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 malloc_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);
+ if(!chunk_is_mmapped(p))
+ {
+ if (!inuse(p)) return 0;
+ check_inuse_chunk(p);
+ return chunksize(p) - SIZE_SZ;
+ }
+ return chunksize(p) - 2*SIZE_SZ;
+ }
+}
+
+
+
+
+/* Utility to update current_mallinfo for malloc_stats and mallinfo() */
+
+#if 0
+static void malloc_update_mallinfo()
+{
+ int i;
+ mbinptr b;
+ mchunkptr p;
+#ifdef DEBUG
+ mchunkptr q;
+#endif
+
+ INTERNAL_SIZE_T avail = chunksize(top);
+ int navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0;
+
+ for (i = 1; i < NAV; ++i)
+ {
+ b = bin_at(i);
+ for (p = last(b); p != b; p = p->bk)
+ {
+#ifdef DEBUG
+ check_free_chunk(p);
+ for (q = next_chunk(p);
+ q < top && inuse(q) && (long)(chunksize(q)) >= (long)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);
+
+}
+#endif /* 0 */
+
+
+
+/*
+
+ malloc_stats:
+
+ Prints on 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.)
+
+*/
+
+#if 0
+void malloc_stats()
+{
+ malloc_update_mallinfo();
+ printf("max system bytes = %10u\n",
+ (unsigned int)(max_total_mem));
+ printf("system bytes = %10u\n",
+ (unsigned int)(sbrked_mem + mmapped_mem));
+ printf("in use bytes = %10u\n",
+ (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
+#if HAVE_MMAP
+ printf("max mmap regions = %10u\n",
+ (unsigned int)max_n_mmaps);
+#endif
+}
+#endif /* 0 */
+
+/*
+ mallinfo returns a copy of updated current mallinfo.
+*/
+
+#if 0
+struct mallinfo mALLINFo()
+{
+ malloc_update_mallinfo();
+ return current_mallinfo;
+}
+#endif /* 0 */
+
+
+
+
+/*
+ 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
+
+ default:
+ return 0;
+ }
+}
+
+/*
+
+History:
+
+ V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee)
+ * return null for negative arguments
+ * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com>
+ * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
+ (e.g. WIN32 platforms)
+ * Cleanup up header file inclusion for WIN32 platforms
+ * Cleanup code to avoid Microsoft Visual C++ compiler complaints
+ * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
+ memory allocation routines
+ * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
+ * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
+ usage of 'assert' in non-WIN32 code
+ * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
+ avoid infinite loop
+ * Always call 'fREe()' rather than 'free()'
+
+ V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee)
+ * Fixed ordering problem with boundary-stamping
+
+ 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.)
+
+*/
+
+
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