After moving all declarations to the C source, do the same with the doc
Done in preparation to provide this documentation for doxygen. Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
This commit is contained in:
parent
e954ee0647
commit
7fd641558b
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@ -5,6 +5,223 @@
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#include <stdio.h>
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#include <module.h>
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/*
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A version of malloc/free/realloc written by Doug Lea and released to the
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public domain. Send questions/comments/complaints/performance data
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||||
to dl@cs.oswego.edu
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||||
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* VERSION 2.6.6 Sun Mar 5 19:10:03 2000 Doug Lea (dl at gee)
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Note: There may be an updated version of this malloc obtainable at
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ftp://g.oswego.edu/pub/misc/malloc.c
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Check before installing!
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||||
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* Why use this malloc?
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This is not the fastest, most space-conserving, most portable, or
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most tunable malloc ever written. However it is among the fastest
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while also being among the most space-conserving, portable and tunable.
|
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Consistent balance across these factors results in a good general-purpose
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allocator. For a high-level description, see
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http://g.oswego.edu/dl/html/malloc.html
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* Synopsis of public routines
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(Much fuller descriptions are contained in the program documentation below.)
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malloc(size_t n);
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Return a pointer to a newly allocated chunk of at least n bytes, or null
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if no space is available.
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free(Void_t* p);
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Release the chunk of memory pointed to by p, or no effect if p is null.
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realloc(Void_t* p, size_t n);
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Return a pointer to a chunk of size n that contains the same data
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as does chunk p up to the minimum of (n, p's size) bytes, or null
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if no space is available. The returned pointer may or may not be
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the same as p. If p is null, equivalent to malloc. Unless the
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#define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
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size argument of zero (re)allocates a minimum-sized chunk.
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memalign(size_t alignment, size_t n);
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Return a pointer to a newly allocated chunk of n bytes, aligned
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in accord with the alignment argument, which must be a power of
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two.
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valloc(size_t n);
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Equivalent to memalign(pagesize, n), where pagesize is the page
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size of the system (or as near to this as can be figured out from
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all the includes/defines below.)
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pvalloc(size_t n);
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Equivalent to valloc(minimum-page-that-holds(n)), that is,
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round up n to nearest pagesize.
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calloc(size_t unit, size_t quantity);
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Returns a pointer to quantity * unit bytes, with all locations
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set to zero.
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cfree(Void_t* p);
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Equivalent to free(p).
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malloc_trim(size_t pad);
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Release all but pad bytes of freed top-most memory back
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to the system. Return 1 if successful, else 0.
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malloc_usable_size(Void_t* p);
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Report the number usable allocated bytes associated with allocated
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chunk p. This may or may not report more bytes than were requested,
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due to alignment and minimum size constraints.
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malloc_stats();
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Prints brief summary statistics on stderr.
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mallinfo()
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Returns (by copy) a struct containing various summary statistics.
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mallopt(int parameter_number, int parameter_value)
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Changes one of the tunable parameters described below. Returns
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1 if successful in changing the parameter, else 0.
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* Vital statistics:
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Alignment: 8-byte
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8 byte alignment is currently hardwired into the design. This
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seems to suffice for all current machines and C compilers.
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Assumed pointer representation: 4 or 8 bytes
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Code for 8-byte pointers is untested by me but has worked
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reliably by Wolfram Gloger, who contributed most of the
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changes supporting this.
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Assumed size_t representation: 4 or 8 bytes
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Note that size_t is allowed to be 4 bytes even if pointers are 8.
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Minimum overhead per allocated chunk: 4 or 8 bytes
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Each malloced chunk has a hidden overhead of 4 bytes holding size
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and status information.
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Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
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8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
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When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
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ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
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needed; 4 (8) for a trailing size field
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and 8 (16) bytes for free list pointers. Thus, the minimum
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allocatable size is 16/24/32 bytes.
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Even a request for zero bytes (i.e., malloc(0)) returns a
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pointer to something of the minimum allocatable size.
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Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes
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8-byte size_t: 2^63 - 16 bytes
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It is assumed that (possibly signed) size_t bit values suffice to
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represent chunk sizes. `Possibly signed' is due to the fact
|
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that `size_t' may be defined on a system as either a signed or
|
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an unsigned type. To be conservative, values that would appear
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as negative numbers are avoided.
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Requests for sizes with a negative sign bit when the request
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size is treaded as a long will return null.
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|
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Maximum overhead wastage per allocated chunk: normally 15 bytes
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|
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Alignnment demands, plus the minimum allocatable size restriction
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make the normal worst-case wastage 15 bytes (i.e., up to 15
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more bytes will be allocated than were requested in malloc), with
|
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two exceptions:
|
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1. Because requests for zero bytes allocate non-zero space,
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the worst case wastage for a request of zero bytes is 24 bytes.
|
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2. For requests >= mmap_threshold that are serviced via
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mmap(), the worst case wastage is 8 bytes plus the remainder
|
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from a system page (the minimal mmap unit); typically 4096 bytes.
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|
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* Limitations
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|
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Here are some features that are NOT currently supported
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* No user-definable hooks for callbacks and the like.
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* No automated mechanism for fully checking that all accesses
|
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to malloced memory stay within their bounds.
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* No support for compaction.
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* Synopsis of compile-time options:
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People have reported using previous versions of this malloc on all
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versions of Unix, sometimes by tweaking some of the defines
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below. It has been tested most extensively on Solaris and
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Linux. It is also reported to work on WIN32 platforms.
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People have also reported adapting this malloc for use in
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stand-alone embedded systems.
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The implementation is in straight, hand-tuned ANSI C. Among other
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consequences, it uses a lot of macros. Because of this, to be at
|
||||
all usable, this code should be compiled using an optimizing compiler
|
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(for example gcc -O2) that can simplify expressions and control
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paths.
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__STD_C (default: derived from C compiler defines)
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Nonzero if using ANSI-standard C compiler, a C++ compiler, or
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a C compiler sufficiently close to ANSI to get away with it.
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DEBUG (default: NOT defined)
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Define to enable debugging. Adds fairly extensive assertion-based
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checking to help track down memory errors, but noticeably slows down
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execution.
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REALLOC_ZERO_BYTES_FREES (default: NOT defined)
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Define this if you think that realloc(p, 0) should be equivalent
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to free(p). Otherwise, since malloc returns a unique pointer for
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malloc(0), so does realloc(p, 0).
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HAVE_MEMCPY (default: defined)
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Define if you are not otherwise using ANSI STD C, but still
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have memcpy and memset in your C library and want to use them.
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Otherwise, simple internal versions are supplied.
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USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
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Define as 1 if you want the C library versions of memset and
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memcpy called in realloc and calloc (otherwise macro versions are used).
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At least on some platforms, the simple macro versions usually
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outperform libc versions.
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HAVE_MMAP (default: defined as 1)
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Define to non-zero to optionally make malloc() use mmap() to
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allocate very large blocks.
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HAVE_MREMAP (default: defined as 0 unless Linux libc set)
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Define to non-zero to optionally make realloc() use mremap() to
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reallocate very large blocks.
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malloc_getpagesize (default: derived from system #includes)
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Either a constant or routine call returning the system page size.
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HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
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Optionally define if you are on a system with a /usr/include/malloc.h
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that declares struct mallinfo. It is not at all necessary to
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define this even if you do, but will ensure consistency.
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INTERNAL_SIZE_T (default: size_t)
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Define to a 32-bit type (probably `unsigned int') if you are on a
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64-bit machine, yet do not want or need to allow malloc requests of
|
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greater than 2^31 to be handled. This saves space, especially for
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very small chunks.
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INTERNAL_LINUX_C_LIB (default: NOT defined)
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Defined only when compiled as part of Linux libc.
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Also note that there is some odd internal name-mangling via defines
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(for example, internally, `malloc' is named `mALLOc') needed
|
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when compiling in this case. These look funny but don't otherwise
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affect anything.
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WIN32 (default: undefined)
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Define this on MS win (95, nt) platforms to compile in sbrk emulation.
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LACKS_UNISTD_H (default: undefined if not WIN32)
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Define this if your system does not have a <unistd.h>.
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LACKS_SYS_PARAM_H (default: undefined if not WIN32)
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Define this if your system does not have a <sys/param.h>.
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MORECORE (default: sbrk)
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The name of the routine to call to obtain more memory from the system.
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MORECORE_FAILURE (default: -1)
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The value returned upon failure of MORECORE.
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MORECORE_CLEARS (default 1)
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True (1) if the routine mapped to MORECORE zeroes out memory (which
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holds for sbrk).
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DEFAULT_TRIM_THRESHOLD
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DEFAULT_TOP_PAD
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DEFAULT_MMAP_THRESHOLD
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DEFAULT_MMAP_MAX
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Default values of tunable parameters (described in detail below)
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controlling interaction with host system routines (sbrk, mmap, etc).
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These values may also be changed dynamically via mallopt(). The
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preset defaults are those that give best performance for typical
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programs/systems.
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USE_DL_PREFIX (default: undefined)
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Prefix all public routines with the string 'dl'. Useful to
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quickly avoid procedure declaration conflicts and linker symbol
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conflicts with existing memory allocation routines.
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*/
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/* to be able to compile this file (is going to be removed) */
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#define __STD_C 1
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|
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217
include/malloc.h
217
include/malloc.h
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@ -1,220 +1,3 @@
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/*
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||||
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 on stderr.
|
||||
mallinfo()
|
||||
Returns (by copy) a struct containing various summary statistics.
|
||||
mallopt(int parameter_number, int parameter_value)
|
||||
Changes one of the tunable parameters described below. Returns
|
||||
1 if successful in changing the parameter, else 0.
|
||||
|
||||
* Vital statistics:
|
||||
|
||||
Alignment: 8-byte
|
||||
8 byte alignment is currently hardwired into the design. This
|
||||
seems to suffice for all current machines and C compilers.
|
||||
|
||||
Assumed pointer representation: 4 or 8 bytes
|
||||
Code for 8-byte pointers is untested by me but has worked
|
||||
reliably by Wolfram Gloger, who contributed most of the
|
||||
changes supporting this.
|
||||
|
||||
Assumed size_t representation: 4 or 8 bytes
|
||||
Note that size_t is allowed to be 4 bytes even if pointers are 8.
|
||||
|
||||
Minimum overhead per allocated chunk: 4 or 8 bytes
|
||||
Each malloced chunk has a hidden overhead of 4 bytes holding size
|
||||
and status information.
|
||||
|
||||
Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
|
||||
8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
|
||||
|
||||
When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
|
||||
ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
|
||||
needed; 4 (8) for a trailing size field
|
||||
and 8 (16) bytes for free list pointers. Thus, the minimum
|
||||
allocatable size is 16/24/32 bytes.
|
||||
|
||||
Even a request for zero bytes (i.e., malloc(0)) returns a
|
||||
pointer to something of the minimum allocatable size.
|
||||
|
||||
Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes
|
||||
8-byte size_t: 2^63 - 16 bytes
|
||||
|
||||
It is assumed that (possibly signed) size_t bit values suffice to
|
||||
represent chunk sizes. `Possibly signed' is due to the fact
|
||||
that `size_t' may be defined on a system as either a signed or
|
||||
an unsigned type. To be conservative, values that would appear
|
||||
as negative numbers are avoided.
|
||||
Requests for sizes with a negative sign bit 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.
|
||||
|
||||
|
||||
*/
|
||||
|
||||
#ifndef __MALLOC_H
|
||||
#define __MALLOC_H
|
||||
|
||||
|
|
Loading…
Reference in New Issue