/*
- * $Id: dlmalloc.c,v 1.2 1998/09/23 17:16:10 wessels Exp $
+ * $Id: dlmalloc.c,v 1.3 2001/01/07 09:55:22 hno Exp $
*/
/* ---------- To make a malloc.h, start cutting here ------------ */
/*
- A version of malloc/free/realloc written by Doug Lea and released to the
- public domain. Send questions/comments/complaints/performance data
- to dl@cs.oswego.edu
-
-* VERSION 2.6.4 Thu Nov 28 07:54:55 1996 Doug Lea (dl at gee)
-
- Note: There may be an updated version of this malloc obtainable at
- ftp://g.oswego.edu/pub/misc/malloc.c
- Check before installing!
-
-* Why use this malloc?
-
- This is not the fastest, most space-conserving, most portable, or
- most tunable malloc ever written. However it is among the fastest
- while also being among the most space-conserving, portable and tunable.
- Consistent balance across these factors results in a good general-purpose
- allocator. For a high-level description, see
- http://g.oswego.edu/dl/html/malloc.html
-
-* Synopsis of public routines
-
- (Much fuller descriptions are contained in the program documentation below.)
-
- malloc(size_t n);
- Return a pointer to a newly allocated chunk of at least n bytes, or null
- if no space is available.
- free(Void_t* p);
- Release the chunk of memory pointed to by p, or no effect if p is null.
- realloc(Void_t* p, size_t n);
- Return a pointer to a chunk of size n that contains the same data
- as does chunk p up to the minimum of (n, p's size) bytes, or null
- if no space is available. The returned pointer may or may not be
- the same as p. If p is null, equivalent to malloc. Unless the
- #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
- size argument of zero (re)allocates a minimum-sized chunk.
- memalign(size_t alignment, size_t n);
- Return a pointer to a newly allocated chunk of n bytes, aligned
- in accord with the alignment argument, which must be a power of
- two.
- valloc(size_t n);
- Equivalent to memalign(pagesize, n), where pagesize is the page
- size of the system (or as near to this as can be figured out from
- all the includes/defines below.)
- pvalloc(size_t n);
- Equivalent to valloc(minimum-page-that-holds(n)), that is,
- round up n to nearest pagesize.
- calloc(size_t unit, size_t quantity);
- Returns a pointer to quantity * unit bytes, with all locations
- set to zero.
- cfree(Void_t* p);
- Equivalent to free(p).
- malloc_trim(size_t pad);
- Release all but pad bytes of freed top-most memory back
- to the system. Return 1 if successful, else 0.
- malloc_usable_size(Void_t* p);
- Report the number usable allocated bytes associated with allocated
- chunk p. This may or may not report more bytes than were requested,
- due to alignment and minimum size constraints.
- malloc_stats();
- Prints brief summary statistics on stderr.
- mallinfo()
- Returns (by copy) a struct containing various summary statistics.
- mallopt(int parameter_number, int parameter_value)
- Changes one of the tunable parameters described below. Returns
- 1 if successful in changing the parameter, else 0.
-
-* Vital statistics:
-
- Alignment: 8-byte
- 8 byte alignment is currently hardwired into the design. This
- seems to suffice for all current machines and C compilers.
-
- Assumed pointer representation: 4 or 8 bytes
- Code for 8-byte pointers is untested by me but has worked
- reliably by Wolfram Gloger, who contributed most of the
- changes supporting this.
-
- Assumed size_t representation: 4 or 8 bytes
- Note that size_t is allowed to be 4 bytes even if pointers are 8.
-
- Minimum overhead per allocated chunk: 4 or 8 bytes
- Each malloced chunk has a hidden overhead of 4 bytes holding size
- and status information.
-
- Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
- 8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
-
- When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
- ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
- needed; 4 (8) for a trailing size field
- and 8 (16) bytes for free list pointers. Thus, the minimum
- allocatable size is 16/24/32 bytes.
-
- Even a request for zero bytes (i.e., malloc(0)) returns a
- pointer to something of the minimum allocatable size.
-
- Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes
- 8-byte size_t: 2^63 - 16 bytes
-
- It is assumed that (possibly signed) size_t bit values suffice to
- represent chunk sizes. `Possibly signed' is due to the fact
- that `size_t' may be defined on a system as either a signed or
- an unsigned type. To be conservative, values that would appear
- as negative numbers are avoided.
- Requests for sizes with a negative sign bit will return a
- minimum-sized chunk.
-
- Maximum overhead wastage per allocated chunk: normally 15 bytes
-
- Alignnment demands, plus the minimum allocatable size restriction
- make the normal worst-case wastage 15 bytes (i.e., up to 15
- more bytes will be allocated than were requested in malloc), with
- two exceptions:
- 1. Because requests for zero bytes allocate non-zero space,
- the worst case wastage for a request of zero bytes is 24 bytes.
- 2. For requests >= mmap_threshold that are serviced via
- mmap(), the worst case wastage is 8 bytes plus the remainder
- from a system page (the minimal mmap unit); typically 4096 bytes.
-
-* Limitations
-
- Here are some features that are NOT currently supported
-
- * No user-definable hooks for callbacks and the like.
- * No automated mechanism for fully checking that all accesses
- to malloced memory stay within their bounds.
- * No support for compaction.
-
-* Synopsis of compile-time options:
-
- People have reported using previous versions of this malloc on all
- versions of Unix, sometimes by tweaking some of the defines
- below. It has been tested most extensively on Solaris and
- Linux. It is also reported to work on WIN32 platforms.
- People have also reported adapting this malloc for use in
- stand-alone embedded systems.
-
- The implementation is in straight, hand-tuned ANSI C. Among other
- consequences, it uses a lot of macros. Because of this, to be at
- all usable, this code should be compiled using an optimizing compiler
- (for example gcc -O2) that can simplify expressions and control
- paths.
-
- __STD_C (default: derived from C compiler defines)
- Nonzero if using ANSI-standard C compiler, a C++ compiler, or
- a C compiler sufficiently close to ANSI to get away with it.
- DEBUG (default: NOT defined)
- Define to enable debugging. Adds fairly extensive assertion-based
- checking to help track down memory errors, but noticeably slows down
- execution.
- REALLOC_ZERO_BYTES_FREES (default: NOT defined)
- Define this if you think that realloc(p, 0) should be equivalent
- to free(p). Otherwise, since malloc returns a unique pointer for
- malloc(0), so does realloc(p, 0).
- HAVE_MEMCPY (default: defined)
- Define if you are not otherwise using ANSI STD C, but still
- have memcpy and memset in your C library and want to use them.
- Otherwise, simple internal versions are supplied.
- USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
- Define as 1 if you want the C library versions of memset and
- memcpy called in realloc and calloc (otherwise macro versions are used).
- At least on some platforms, the simple macro versions usually
- outperform libc versions.
- HAVE_MMAP (default: defined as 1)
- Define to non-zero to optionally make malloc() use mmap() to
- allocate very large blocks.
- HAVE_MREMAP (default: defined as 0 unless Linux libc set)
- Define to non-zero to optionally make realloc() use mremap() to
- reallocate very large blocks.
- malloc_getpagesize (default: derived from system #includes)
- Either a constant or routine call returning the system page size.
- HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
- Optionally define if you are on a system with a /usr/include/malloc.h
- that declares struct mallinfo. It is not at all necessary to
- define this even if you do, but will ensure consistency.
- INTERNAL_SIZE_T (default: size_t)
- Define to a 32-bit type (probably `unsigned int') if you are on a
- 64-bit machine, yet do not want or need to allow malloc requests of
- greater than 2^31 to be handled. This saves space, especially for
- very small chunks.
- INTERNAL_LINUX_C_LIB (default: NOT defined)
- Defined only when compiled as part of Linux libc.
- Also note that there is some odd internal name-mangling via defines
- (for example, internally, `malloc' is named `mALLOc') needed
- when compiling in this case. These look funny but don't otherwise
- affect anything.
- WIN32 (default: undefined)
- Define this on MS win (95, nt) platforms to compile in sbrk emulation.
- LACKS_UNISTD_H (default: undefined)
- Define this if your system does not have a <unistd.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.
-
-
-*/
-
+ * A version of malloc/free/realloc written by Doug Lea and released to the
+ * public domain. Send questions/comments/complaints/performance data
+ * to dl@cs.oswego.edu
+ *
+ * * VERSION 2.6.4 Thu Nov 28 07:54:55 1996 Doug Lea (dl at gee)
+ *
+ * Note: There may be an updated version of this malloc obtainable at
+ * ftp://g.oswego.edu/pub/misc/malloc.c
+ * Check before installing!
+ *
+ * * Why use this malloc?
+ *
+ * This is not the fastest, most space-conserving, most portable, or
+ * most tunable malloc ever written. However it is among the fastest
+ * while also being among the most space-conserving, portable and tunable.
+ * Consistent balance across these factors results in a good general-purpose
+ * allocator. For a high-level description, see
+ * http://g.oswego.edu/dl/html/malloc.html
+ *
+ * * Synopsis of public routines
+ *
+ * (Much fuller descriptions are contained in the program documentation below.)
+ *
+ * malloc(size_t n);
+ * Return a pointer to a newly allocated chunk of at least n bytes, or null
+ * if no space is available.
+ * free(Void_t* p);
+ * Release the chunk of memory pointed to by p, or no effect if p is null.
+ * realloc(Void_t* p, size_t n);
+ * Return a pointer to a chunk of size n that contains the same data
+ * as does chunk p up to the minimum of (n, p's size) bytes, or null
+ * if no space is available. The returned pointer may or may not be
+ * the same as p. If p is null, equivalent to malloc. Unless the
+ * #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a
+ * size argument of zero (re)allocates a minimum-sized chunk.
+ * memalign(size_t alignment, size_t n);
+ * Return a pointer to a newly allocated chunk of n bytes, aligned
+ * in accord with the alignment argument, which must be a power of
+ * two.
+ * valloc(size_t n);
+ * Equivalent to memalign(pagesize, n), where pagesize is the page
+ * size of the system (or as near to this as can be figured out from
+ * all the includes/defines below.)
+ * pvalloc(size_t n);
+ * Equivalent to valloc(minimum-page-that-holds(n)), that is,
+ * round up n to nearest pagesize.
+ * calloc(size_t unit, size_t quantity);
+ * Returns a pointer to quantity * unit bytes, with all locations
+ * set to zero.
+ * cfree(Void_t* p);
+ * Equivalent to free(p).
+ * malloc_trim(size_t pad);
+ * Release all but pad bytes of freed top-most memory back
+ * to the system. Return 1 if successful, else 0.
+ * malloc_usable_size(Void_t* p);
+ * Report the number usable allocated bytes associated with allocated
+ * chunk p. This may or may not report more bytes than were requested,
+ * due to alignment and minimum size constraints.
+ * malloc_stats();
+ * Prints brief summary statistics on stderr.
+ * mallinfo()
+ * Returns (by copy) a struct containing various summary statistics.
+ * mallopt(int parameter_number, int parameter_value)
+ * Changes one of the tunable parameters described below. Returns
+ * 1 if successful in changing the parameter, else 0.
+ *
+ * * Vital statistics:
+ *
+ * Alignment: 8-byte
+ * 8 byte alignment is currently hardwired into the design. This
+ * seems to suffice for all current machines and C compilers.
+ *
+ * Assumed pointer representation: 4 or 8 bytes
+ * Code for 8-byte pointers is untested by me but has worked
+ * reliably by Wolfram Gloger, who contributed most of the
+ * changes supporting this.
+ *
+ * Assumed size_t representation: 4 or 8 bytes
+ * Note that size_t is allowed to be 4 bytes even if pointers are 8.
+ *
+ * Minimum overhead per allocated chunk: 4 or 8 bytes
+ * Each malloced chunk has a hidden overhead of 4 bytes holding size
+ * and status information.
+ *
+ * Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead)
+ * 8-byte ptrs: 24/32 bytes (including, 4/8 overhead)
+ *
+ * When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte
+ * ptrs but 4 byte size) or 24 (for 8/8) additional bytes are
+ * needed; 4 (8) for a trailing size field
+ * and 8 (16) bytes for free list pointers. Thus, the minimum
+ * allocatable size is 16/24/32 bytes.
+ *
+ * Even a request for zero bytes (i.e., malloc(0)) returns a
+ * pointer to something of the minimum allocatable size.
+ *
+ * Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes
+ * 8-byte size_t: 2^63 - 16 bytes
+ *
+ * It is assumed that (possibly signed) size_t bit values suffice to
+ * represent chunk sizes. `Possibly signed' is due to the fact
+ * that `size_t' may be defined on a system as either a signed or
+ * an unsigned type. To be conservative, values that would appear
+ * as negative numbers are avoided.
+ * Requests for sizes with a negative sign bit will return a
+ * minimum-sized chunk.
+ *
+ * Maximum overhead wastage per allocated chunk: normally 15 bytes
+ *
+ * Alignnment demands, plus the minimum allocatable size restriction
+ * make the normal worst-case wastage 15 bytes (i.e., up to 15
+ * more bytes will be allocated than were requested in malloc), with
+ * two exceptions:
+ * 1. Because requests for zero bytes allocate non-zero space,
+ * the worst case wastage for a request of zero bytes is 24 bytes.
+ * 2. For requests >= mmap_threshold that are serviced via
+ * mmap(), the worst case wastage is 8 bytes plus the remainder
+ * from a system page (the minimal mmap unit); typically 4096 bytes.
+ *
+ * * Limitations
+ *
+ * Here are some features that are NOT currently supported
+ *
+ * * No user-definable hooks for callbacks and the like.
+ * * No automated mechanism for fully checking that all accesses
+ * to malloced memory stay within their bounds.
+ * * No support for compaction.
+ *
+ * * Synopsis of compile-time options:
+ *
+ * People have reported using previous versions of this malloc on all
+ * versions of Unix, sometimes by tweaking some of the defines
+ * below. It has been tested most extensively on Solaris and
+ * Linux. It is also reported to work on WIN32 platforms.
+ * People have also reported adapting this malloc for use in
+ * stand-alone embedded systems.
+ *
+ * The implementation is in straight, hand-tuned ANSI C. Among other
+ * consequences, it uses a lot of macros. Because of this, to be at
+ * all usable, this code should be compiled using an optimizing compiler
+ * (for example gcc -O2) that can simplify expressions and control
+ * paths.
+ *
+ * __STD_C (default: derived from C compiler defines)
+ * Nonzero if using ANSI-standard C compiler, a C++ compiler, or
+ * a C compiler sufficiently close to ANSI to get away with it.
+ * DEBUG (default: NOT defined)
+ * Define to enable debugging. Adds fairly extensive assertion-based
+ * checking to help track down memory errors, but noticeably slows down
+ * execution.
+ * REALLOC_ZERO_BYTES_FREES (default: NOT defined)
+ * Define this if you think that realloc(p, 0) should be equivalent
+ * to free(p). Otherwise, since malloc returns a unique pointer for
+ * malloc(0), so does realloc(p, 0).
+ * HAVE_MEMCPY (default: defined)
+ * Define if you are not otherwise using ANSI STD C, but still
+ * have memcpy and memset in your C library and want to use them.
+ * Otherwise, simple internal versions are supplied.
+ * USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise)
+ * Define as 1 if you want the C library versions of memset and
+ * memcpy called in realloc and calloc (otherwise macro versions are used).
+ * At least on some platforms, the simple macro versions usually
+ * outperform libc versions.
+ * HAVE_MMAP (default: defined as 1)
+ * Define to non-zero to optionally make malloc() use mmap() to
+ * allocate very large blocks.
+ * HAVE_MREMAP (default: defined as 0 unless Linux libc set)
+ * Define to non-zero to optionally make realloc() use mremap() to
+ * reallocate very large blocks.
+ * malloc_getpagesize (default: derived from system #includes)
+ * Either a constant or routine call returning the system page size.
+ * HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined)
+ * Optionally define if you are on a system with a /usr/include/malloc.h
+ * that declares struct mallinfo. It is not at all necessary to
+ * define this even if you do, but will ensure consistency.
+ * INTERNAL_SIZE_T (default: size_t)
+ * Define to a 32-bit type (probably `unsigned int') if you are on a
+ * 64-bit machine, yet do not want or need to allow malloc requests of
+ * greater than 2^31 to be handled. This saves space, especially for
+ * very small chunks.
+ * INTERNAL_LINUX_C_LIB (default: NOT defined)
+ * Defined only when compiled as part of Linux libc.
+ * Also note that there is some odd internal name-mangling via defines
+ * (for example, internally, `malloc' is named `mALLOc') needed
+ * when compiling in this case. These look funny but don't otherwise
+ * affect anything.
+ * WIN32 (default: undefined)
+ * Define this on MS win (95, nt) platforms to compile in sbrk emulation.
+ * LACKS_UNISTD_H (default: undefined)
+ * Define this if your system does not have a <unistd.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.
+ *
+ *
+ */
\f
+
/* Preliminaries */
#ifndef __STD_C
#define __STD_C 1
#else
#define __STD_C 0
-#endif /*__cplusplus*/
-#endif /*__STDC__*/
-#endif /*__STD_C*/
-
-#ifndef Void_t
-#if __STD_C
-#define Void_t void
-#else
-#define Void_t char
-#endif
-#endif /*Void_t*/
-
-#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.
-
-*/
-
-#if 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
-#endif
-
-
-/*
- HAVE_MEMCPY should be defined if you are not otherwise using
- ANSI STD C, but still have memcpy and memset in your C library
- and want to use them in calloc and realloc. Otherwise simple
- macro versions are defined here.
-
- USE_MEMCPY should be defined as 1 if you actually want to
- have memset and memcpy called. People report that the macro
- versions are often enough faster than libc versions on many
- systems that it is better to use them.
-
-*/
-
-#define HAVE_MEMCPY
-
-#ifndef USE_MEMCPY
-#ifdef HAVE_MEMCPY
-#define USE_MEMCPY 1
-#else
-#define USE_MEMCPY 0
-#endif
-#endif
-
-#if (__STD_C || defined(HAVE_MEMCPY))
-
-#if __STD_C
-void* memset(void*, int, size_t);
-void* memcpy(void*, const void*, size_t);
-#else
-Void_t* memset();
-Void_t* memcpy();
-#endif
-#endif
-
-#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
-# include <sys/param.h>
-# ifdef EXEC_PAGESIZE
-# define malloc_getpagesize EXEC_PAGESIZE
-# else
-# ifdef NBPG
-# ifndef CLSIZE
-# define malloc_getpagesize NBPG
-# else
-# define malloc_getpagesize (NBPG * CLSIZE)
-# endif
-# else
-# ifdef NBPC
-# define malloc_getpagesize NBPC
-# else
-# ifdef PAGESIZE
-# define malloc_getpagesize PAGESIZE
-# else
-# define malloc_getpagesize (4096) /* just guess */
-# endif
-# endif
-# endif
-# endif
-# endif
-# endif
-#endif
-
-
-
-/*
-
- This version of malloc supports the standard SVID/XPG mallinfo
- routine that returns a struct containing the same kind of
- information you can get from malloc_stats. It should work on
- any SVID/XPG compliant system that has a /usr/include/malloc.h
- defining struct mallinfo. (If you'd like to install such a thing
- yourself, cut out the preliminary declarations as described above
- and below and save them in a malloc.h file. But there's no
- compelling reason to bother to do this.)
-
- The main declaration needed is the mallinfo struct that is returned
- (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a
- bunch of fields, most of which are not even meaningful in this
- version of malloc. Some of these fields are are instead filled by
- mallinfo() with other numbers that might possibly be of interest.
-
- HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
- /usr/include/malloc.h file that includes a declaration of struct
- mallinfo. If so, it is included; else an SVID2/XPG2 compliant
- version is declared below. These must be precisely the same for
- mallinfo() to work.
-
-*/
-
-/* #define HAVE_USR_INCLUDE_MALLOC_H */
-
-#if HAVE_USR_INCLUDE_MALLOC_H
-#include "/usr/include/malloc.h"
-#else
-
-/* SVID2/XPG mallinfo structure */
-
-struct mallinfo {
- int arena; /* total space allocated from system */
- int ordblks; /* number of non-inuse chunks */
- int smblks; /* unused -- always zero */
- int hblks; /* number of mmapped regions */
- int hblkhd; /* total space in mmapped regions */
- int usmblks; /* unused -- always zero */
- int fsmblks; /* unused -- always zero */
- int uordblks; /* total allocated space */
- int fordblks; /* total non-inuse space */
- int keepcost; /* top-most, releasable (via malloc_trim) space */
-};
-
-/* SVID2/XPG mallopt options */
-
-#define M_MXFAST 1 /* UNUSED in this malloc */
-#define M_NLBLKS 2 /* UNUSED in this malloc */
-#define M_GRAIN 3 /* UNUSED in this malloc */
-#define M_KEEP 4 /* UNUSED in this malloc */
-
#endif
-
-/* mallopt options that actually do something */
-
-#define M_TRIM_THRESHOLD -1
-#define M_TOP_PAD -2
-#define M_MMAP_THRESHOLD -3
-#define M_MMAP_MAX -4
-
-
-
-#ifndef DEFAULT_TRIM_THRESHOLD
-#define DEFAULT_TRIM_THRESHOLD (128 * 1024)
-#endif
-
-/*
- M_TRIM_THRESHOLD is the maximum amount of unused top-most memory
- to keep before releasing via malloc_trim in free().
-
- Automatic trimming is mainly useful in long-lived programs.
- Because trimming via sbrk can be slow on some systems, and can
- sometimes be wasteful (in cases where programs immediately
- afterward allocate more large chunks) the value should be high
- enough so that your overall system performance would improve by
- releasing.
-
- The trim threshold and the mmap control parameters (see below)
- can be traded off with one another. Trimming and mmapping are
- two different ways of releasing unused memory back to the
- system. Between these two, it is often possible to keep
- system-level demands of a long-lived program down to a bare
- minimum. For example, in one test suite of sessions measuring
- the XF86 X server on Linux, using a trim threshold of 128K and a
- mmap threshold of 192K led to near-minimal long term resource
- consumption.
-
- If you are using this malloc in a long-lived program, it should
- pay to experiment with these values. As a rough guide, you
- might set to a value close to the average size of a process
- (program) running on your system. Releasing this much memory
- would allow such a process to run in memory. Generally, it's
- worth it to tune for trimming rather tham memory mapping when a
- program undergoes phases where several large chunks are
- allocated and released in ways that can reuse each other's
- storage, perhaps mixed with phases where there are no such
- chunks at all. And in well-behaved long-lived programs,
- controlling release of large blocks via trimming versus mapping
- is usually faster.
-
- However, in most programs, these parameters serve mainly as
- protection against the system-level effects of carrying around
- massive amounts of unneeded memory. Since frequent calls to
- sbrk, mmap, and munmap otherwise degrade performance, the default
- parameters are set to relatively high values that serve only as
- safeguards.
-
- The default trim value is high enough to cause trimming only in
- fairly extreme (by current memory consumption standards) cases.
- It must be greater than page size to have any useful effect. To
- disable trimming completely, you can set to (unsigned long)(-1);
-
-
-*/
-
-
-#ifndef DEFAULT_TOP_PAD
-#define DEFAULT_TOP_PAD (0)
-#endif
-
-/*
- M_TOP_PAD is the amount of extra `padding' space to allocate or
- retain whenever sbrk is called. It is used in two ways internally:
-
- * When sbrk is called to extend the top of the arena to satisfy
- a new malloc request, this much padding is added to the sbrk
- request.
-
- * When malloc_trim is called automatically from free(),
- it is used as the `pad' argument.
-
- In both cases, the actual amount of padding is rounded
- so that the end of the arena is always a system page boundary.
-
- The main reason for using padding is to avoid calling sbrk so
- often. Having even a small pad greatly reduces the likelihood
- that nearly every malloc request during program start-up (or
- after trimming) will invoke sbrk, which needlessly wastes
- time.
-
- Automatic rounding-up to page-size units is normally sufficient
- to avoid measurable overhead, so the default is 0. However, in
- systems where sbrk is relatively slow, it can pay to increase
- this value, at the expense of carrying around more memory than
- the program needs.
-
-*/
-
-
-#ifndef DEFAULT_MMAP_THRESHOLD
-#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
-#endif
-
-/*
-
- M_MMAP_THRESHOLD is the request size threshold for using mmap()
- to service a request. Requests of at least this size that cannot
- be allocated using already-existing space will be serviced via mmap.
- (If enough normal freed space already exists it is used instead.)
-
- Using mmap segregates relatively large chunks of memory so that
- they can be individually obtained and released from the host
- system. A request serviced through mmap is never reused by any
- other request (at least not directly; the system may just so
- happen to remap successive requests to the same locations).
-
- Segregating space in this way has the benefit that mmapped space
- can ALWAYS be individually released back to the system, which
- helps keep the system level memory demands of a long-lived
- program low. Mapped memory can never become `locked' between
- other chunks, as can happen with normally allocated chunks, which
- menas that even trimming via malloc_trim would not release them.
-
- However, it has the disadvantages that:
-
- 1. The space cannot be reclaimed, consolidated, and then
- used to service later requests, as happens with normal chunks.
- 2. It can lead to more wastage because of mmap page alignment
- requirements
- 3. It causes malloc performance to be more dependent on host
- system memory management support routines which may vary in
- implementation quality and may impose arbitrary
- limitations. Generally, servicing a request via normal
- malloc steps is faster than going through a system's mmap.
-
- All together, these considerations should lead you to use mmap
- only for relatively large requests.
-
-
-*/
-
-
-
-#ifndef DEFAULT_MMAP_MAX
-#if HAVE_MMAP
-#define DEFAULT_MMAP_MAX (64)
-#else
-#define DEFAULT_MMAP_MAX (0)
-#endif
-#endif
-
-/*
- M_MMAP_MAX is the maximum number of requests to simultaneously
- service using mmap. This parameter exists because:
-
- 1. Some systems have a limited number of internal tables for
- use by mmap.
- 2. In most systems, overreliance on mmap can degrade overall
- performance.
- 3. If a program allocates many large regions, it is probably
- better off using normal sbrk-based allocation routines that
- can reclaim and reallocate normal heap memory. Using a
- small value allows transition into this mode after the
- first few allocations.
-
- Setting to 0 disables all use of mmap. If HAVE_MMAP is not set,
- the default value is 0, and attempts to set it to non-zero values
- in mallopt will fail.
-*/
-
-
-
-
-/*
-
- Special defines for linux libc
-
- Except when compiled using these special defines for Linux libc
- using weak aliases, this malloc is NOT designed to work in
- multithreaded applications. No semaphores or other concurrency
- control are provided to ensure that multiple malloc or free calls
- don't run at the same time, which could be disasterous. A single
- semaphore could be used across malloc, realloc, and free (which is
- essentially the effect of the linux weak alias approach). It would
- be hard to obtain finer granularity.
-
-*/
-
-
-#ifdef INTERNAL_LINUX_C_LIB
-
-#if __STD_C
-
-Void_t * __default_morecore_init (ptrdiff_t);
-Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;
-
-#else
-
-Void_t * __default_morecore_init ();
-Void_t *(*__morecore)() = __default_morecore_init;
-
-#endif
-
-#define MORECORE (*__morecore)
-#define MORECORE_FAILURE 0
-#define MORECORE_CLEARS 1
-
-#else /* INTERNAL_LINUX_C_LIB */
-
-#if __STD_C
-extern Void_t* sbrk(ptrdiff_t);
-#else
-extern Void_t* sbrk();
-#endif
-
-#ifndef MORECORE
-#define MORECORE sbrk
-#endif
-
-#ifndef MORECORE_FAILURE
-#define MORECORE_FAILURE -1
-#endif
-
-#ifndef MORECORE_CLEARS
-#define MORECORE_CLEARS 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
-
-
-#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
-
-/* 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 ------------ */
-
-
-/*
- Emulation of sbrk for WIN32
- All code within the ifdef WIN32 is untested by me.
-*/
-
-
-#ifdef WIN32
-
-#define AlignPage(add) (((add) + (malloc_getpagesize-1)) &
-~(malloc_getpagesize-1))
-
-/* resrve 64MB to insure large contiguous space */
-#define RESERVED_SIZE (1024*1024*64)
-#define NEXT_SIZE (2048*1024)
-#define TOP_MEMORY ((unsigned long)2*1024*1024*1024)
-
-struct GmListElement;
-typedef struct GmListElement GmListElement;
-
-struct GmListElement
-{
- GmListElement* next;
- void* base;
-};
-
-static GmListElement* head = 0;
-static unsigned int gNextAddress = 0;
-static unsigned int gAddressBase = 0;
-static unsigned int gAllocatedSize = 0;
-
-static
-GmListElement* makeGmListElement (void* bas)
-{
- GmListElement* this;
- this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement));
- ASSERT (this);
- if (this)
- {
- this->base = bas;
- this->next = head;
- head = this;
- }
- return this;
-}
-
-void gcleanup ()
-{
- BOOL rval;
- ASSERT ( (head == NULL) || (head->base == (void*)gAddressBase));
- if (gAddressBase && (gNextAddress - gAddressBase))
- {
- rval = VirtualFree ((void*)gAddressBase,
- gNextAddress - gAddressBase,
- MEM_DECOMMIT);
- ASSERT (rval);
- }
- while (head)
- {
- GmListElement* next = head->next;
- rval = VirtualFree (head->base, 0, MEM_RELEASE);
- ASSERT (rval);
- LocalFree (head);
- head = next;
- }
-}
-
-static
-void* findRegion (void* start_address, unsigned long size)
-{
- MEMORY_BASIC_INFORMATION info;
- while ((unsigned long)start_address < TOP_MEMORY)
- {
- VirtualQuery (start_address, &info, sizeof (info));
- if (info.State != MEM_FREE)
- start_address = (char*)info.BaseAddress + info.RegionSize;
- else if (info.RegionSize >= size)
- return start_address;
- else
- start_address = (char*)info.BaseAddress + info.RegionSize;
- }
- return NULL;
-
-}
-
-
-void* wsbrk (long size)
-{
- void* tmp;
- if (size > 0)
- {
- if (gAddressBase == 0)
- {
- gAllocatedSize = max (RESERVED_SIZE, AlignPage (size));
- gNextAddress = gAddressBase =
- (unsigned int)VirtualAlloc (NULL, gAllocatedSize,
- MEM_RESERVE, PAGE_NOACCESS);
- } else if (AlignPage (gNextAddress + size) > (gAddressBase +
-gAllocatedSize))
- {
- long new_size = max (NEXT_SIZE, AlignPage (size));
- void* new_address = (void*)(gAddressBase+gAllocatedSize);
- do
- {
- new_address = findRegion (new_address, new_size);
-
- if (new_address == 0)
- return (void*)-1;
-
- gAddressBase = gNextAddress =
- (unsigned int)VirtualAlloc (new_address, new_size,
- MEM_RESERVE, PAGE_NOACCESS);
- // repeat in case of race condition
- // The region that we found has been snagged
- // by another thread
- }
- while (gAddressBase == 0);
-
- ASSERT (new_address == (void*)gAddressBase);
-
- gAllocatedSize = new_size;
-
- if (!makeGmListElement ((void*)gAddressBase))
- return (void*)-1;
- }
- if ((size + gNextAddress) > AlignPage (gNextAddress))
- {
- void* res;
- res = VirtualAlloc ((void*)AlignPage (gNextAddress),
- (size + gNextAddress -
- AlignPage (gNextAddress)),
- MEM_COMMIT, PAGE_READWRITE);
- if (res == 0)
- return (void*)-1;
- }
- tmp = (void*)gNextAddress;
- gNextAddress = (unsigned int)tmp + size;
- return tmp;
- }
- else if (size < 0)
- {
- unsigned int alignedGoal = AlignPage (gNextAddress + size);
- /* Trim by releasing the virtual memory */
- if (alignedGoal >= gAddressBase)
- {
- VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal,
- MEM_DECOMMIT);
- gNextAddress = gNextAddress + size;
- return (void*)gNextAddress;
- }
- else
- {
- VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase,
- MEM_DECOMMIT);
- gNextAddress = gAddressBase;
- return (void*)-1;
- }
- }
- else
- {
- return (void*)gNextAddress;
- }
-}
-
-#endif
-
-\f
-
-/*
- 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.
-
-*/
-
-
-
-\f
-
-
-/* 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)
-
-
-\f
-
-/*
- 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)))
-
-
-\f
-
-/*
- 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))
-
-
-\f
-
-/*
- 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))
-
-
-\f
-
-
-/*
- 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)
-};
-
-\f
-
-/* 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)
-
-\f
-
-/*
- 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)))
-
-
-\f
-
-
-/* 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 */
-
-static unsigned int n_mmaps = 0;
-static unsigned int max_n_mmaps = 0;
-static unsigned long mmapped_mem = 0;
-static unsigned long max_mmapped_mem = 0;
-
-\f
-
-/*
- Debugging support
-*/
-
-#if 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
-{
- INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
-
- /* 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;
- mchunkptr next = chunk_at_offset(p, sz);
-
- 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
-{
- INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
- long room = sz - s;
-
- 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
-
-\f
-
-/*
- 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)
-
-
-
-\f
-
-
-/* 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 */
-
-
-\f
-
-/*
- 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 += pagesz - ((unsigned long)(brk + sbrk_size) & (pagesz - 1));
-
- /* 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;
- chunk_at_offset(old_top, old_top_size )->size =
- SIZE_SZ|PREV_INUSE;
- chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size =
- SIZE_SZ|PREV_INUSE;
- set_head_size(old_top, old_top_size);
- /* If possible, release the rest. */
- if (old_top_size >= MINSIZE)
- 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);
-}
-
-
-\f
-
-/* Main public routines */
-
-
-/*
- Malloc Algorthim:
-
- The requested size is first converted into a usable form, `nb'.
- This currently means to add 4 bytes overhead plus possibly more to
- obtain 8-byte alignment and/or to obtain a size of at least
- MINSIZE (currently 16 bytes), the smallest allocatable size.
- (All fits are considered `exact' if they are within MINSIZE bytes.)
-
- From there, the first successful of the following steps is taken:
-
- 1. The bin corresponding to the request size is scanned, and if
- a chunk of exactly the right size is found, it is taken.
-
- 2. The most recently remaindered chunk is used if it is big
- enough. This is a form of (roving) first fit, used only in
- the absence of exact fits. Runs of consecutive requests use
- the remainder of the chunk used for the previous such request
- whenever possible. This limited use of a first-fit style
- allocation strategy tends to give contiguous chunks
- coextensive lifetimes, which improves locality and can reduce
- fragmentation in the long run.
-
- 3. Other bins are scanned in increasing size order, using a
- chunk big enough to fulfill the request, and splitting off
- any remainder. This search is strictly by best-fit; i.e.,
- the smallest (with ties going to approximately the least
- recently used) chunk that fits is selected.
-
- 4. If large enough, the chunk bordering the end of memory
- (`top') is split off. (This use of `top' is in accord with
- the best-fit search rule. In effect, `top' is treated as
- larger (and thus less well fitting) than any other available
- chunk since it can be extended to be as large as necessary
- (up to system limitations).
-
- 5. If the request size meets the mmap threshold and the
- system supports mmap, and there are few enough currently
- allocated mmapped regions, and a call to mmap succeeds,
- the request is allocated via direct memory mapping.
-
- 6. Otherwise, the top of memory is extended by
- obtaining more space from the system (normally using sbrk,
- but definable to anything else via the MORECORE macro).
- Memory is gathered from the system (in system page-sized
- units) in a way that allows chunks obtained across different
- sbrk calls to be consolidated, but does not require
- contiguous memory. Thus, it should be safe to intersperse
- mallocs with other sbrk calls.
-
-
- All allocations are made from the the `lowest' part of any found
- chunk. (The implementation invariant is that prev_inuse is
- always true of any allocated chunk; i.e., that each allocated
- chunk borders either a previously allocated and still in-use chunk,
- or the base of its memory arena.)
-
-*/
-
-#if __STD_C
-Void_t* mALLOc(size_t bytes)
-#else
-Void_t* mALLOc(bytes) size_t bytes;
-#endif
-{
- mchunkptr victim; /* inspected/selected chunk */
- INTERNAL_SIZE_T victim_size; /* its size */
- int idx; /* index for bin traversal */
- mbinptr bin; /* associated bin */
- mchunkptr remainder; /* remainder from a split */
- long remainder_size; /* its size */
- int remainder_index; /* its bin index */
- unsigned long block; /* block traverser bit */
- int startidx; /* first bin of a traversed block */
- mchunkptr fwd; /* misc temp for linking */
- mchunkptr bck; /* misc temp for linking */
- mbinptr q; /* misc temp */
-
- INTERNAL_SIZE_T nb = request2size(bytes); /* padded request size; */
-
- /* Check for exact match in a bin */
-
- if (is_small_request(nb)) /* Faster version for small requests */
- {
- idx = smallbin_index(nb);
-
- /* No traversal or size check necessary for small bins. */
-
- q = bin_at(idx);
- victim = last(q);
-
- /* Also scan the next one, since it would have a remainder < MINSIZE */
- if (victim == q)
- {
- q = next_bin(q);
- victim = last(q);
- }
- if (victim != q)
- {
- victim_size = chunksize(victim);
- unlink(victim, bck, fwd);
- set_inuse_bit_at_offset(victim, victim_size);
- check_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);
-
-}
-
-
-\f
-
-/*
-
- 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, -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, -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);
-}
-
-
-\f
-
-
-/*
-
- Realloc algorithm:
-
- Chunks that were obtained via mmap cannot be extended or shrunk
- unless HAVE_MREMAP is defined, in which case mremap is used.
- Otherwise, if their reallocation is for additional space, they are
- copied. If for less, they are just left alone.
-
- Otherwise, if the reallocation is for additional space, and the
- chunk can be extended, it is, else a malloc-copy-free sequence is
- taken. There are several different ways that a chunk could be
- extended. All are tried:
-
- * Extending forward into following adjacent free chunk.
- * Shifting backwards, joining preceding adjacent space
- * Both shifting backwards and extending forward.
- * Extending into newly sbrked space
-
- Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a
- size argument of zero (re)allocates a minimum-sized chunk.
-
- If the reallocation is for less space, and the new request is for
- a `small' (<512 bytes) size, then the newly unused space is lopped
- off and freed.
-
- The old unix realloc convention of allowing the last-free'd chunk
- to be used as an argument to realloc is no longer supported.
- I don't know of any programs still relying on this feature,
- and allowing it would also allow too many other incorrect
- usages of realloc to be sensible.
-
-
-*/
-
-
-#if __STD_C
-Void_t* rEALLOc(Void_t* oldmem, size_t bytes)
-#else
-Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes;
-#endif
-{
- INTERNAL_SIZE_T nb; /* padded request size */
-
- mchunkptr oldp; /* chunk corresponding to oldmem */
- INTERNAL_SIZE_T oldsize; /* its size */
-
- mchunkptr newp; /* chunk to return */
- INTERNAL_SIZE_T newsize; /* its size */
- Void_t* newmem; /* corresponding user mem */
-
- mchunkptr next; /* next contiguous chunk after oldp */
- INTERNAL_SIZE_T nextsize; /* its size */
-
- mchunkptr prev; /* previous contiguous chunk before oldp */
- INTERNAL_SIZE_T prevsize; /* its size */
-
- mchunkptr remainder; /* holds split off extra space from newp */
- INTERNAL_SIZE_T remainder_size; /* its size */
-
- mchunkptr bck; /* misc temp for linking */
- mchunkptr fwd; /* misc temp for linking */
-
-#ifdef REALLOC_ZERO_BYTES_FREES
- if (bytes == 0) { fREe(oldmem); return 0; }
-#endif
-
-
- /* realloc of null is supposed to be same as malloc */
- if (oldmem == 0) return mALLOc(bytes);
-
- newp = oldp = mem2chunk(oldmem);
- newsize = oldsize = chunksize(oldp);
-
-
- nb = request2size(bytes);
-
-#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);
-}
-
-
-\f
-
-/*
-
- 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 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)) & -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);
-
-}
-
-\f
-
-
-/*
- valloc just invokes memalign with alignment argument equal
- to the page size of the system (or as near to this as can
- be figured out from all the includes/defines above.)
-*/
-
-#if __STD_C
-Void_t* vALLOc(size_t bytes)
-#else
-Void_t* vALLOc(bytes) size_t bytes;
-#endif
-{
- return mEMALIGn (malloc_getpagesize, bytes);
-}
-
-/*
- pvalloc just invokes valloc for the nearest pagesize
- that will accommodate request
-*/
-
-
-#if __STD_C
-Void_t* pvALLOc(size_t bytes)
-#else
-Void_t* pvALLOc(bytes) size_t bytes;
-#endif
-{
- size_t pagesize = malloc_getpagesize;
- return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1));
-}
-
-/*
-
- calloc calls malloc, then zeroes out the allocated chunk.
-
-*/
-
-#if __STD_C
-Void_t* cALLOc(size_t n, size_t elem_size)
-#else
-Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size;
-#endif
-{
- mchunkptr p;
- INTERNAL_SIZE_T csz;
-
- INTERNAL_SIZE_T sz = n * elem_size;
-
- /* check if expand_top called, in which case don't need to clear */
-#if MORECORE_CLEARS
- mchunkptr oldtop = top;
- INTERNAL_SIZE_T oldtopsize = chunksize(top);
-#endif
- Void_t* mem = mALLOc (sz);
-
- if (mem == 0)
- return 0;
- else
- {
- p = mem2chunk(mem);
-
- /* Two optional cases in which clearing not necessary */
-
-
-#if HAVE_MMAP
- if (chunk_is_mmapped(p)) return mem;
-#endif
-
- csz = chunksize(p);
-
-#if MORECORE_CLEARS
- if (p == oldtop && csz > oldtopsize)
- {
- /* clear only the bytes from non-freshly-sbrked memory */
- csz = oldtopsize;
- }
-#endif
-
- MALLOC_ZERO(mem, csz - 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
-
-\f
-
-/*
-
- 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;
- }
- }
- }
-}
-
-\f
-
-/*
- 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;
- }
-}
-
-
-\f
-
-/* Utility to update current_mallinfo for malloc_stats and mallinfo() */
-
-static void malloc_update_mallinfo()
-{
- int i;
- mbinptr b;
- mchunkptr p;
-#if 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)
- {
-#if 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);
-
-}
-
-\f
-
-/*
-
- malloc_stats:
-
- Prints on stderr the amount of space obtain from the system (both
- via sbrk and mmap), the maximum amount (which may be more than
- current if malloc_trim and/or munmap got called), the maximum
- number of simultaneous mmap regions used, and the current number
- of bytes allocated via malloc (or realloc, etc) but not yet
- freed. (Note that this is the number of bytes allocated, not the
- number requested. It will be larger than the number requested
- because of alignment and bookkeeping overhead.)
-
-*/
-
-void malloc_stats()
-{
- malloc_update_mallinfo();
- fprintf(stderr, "max system bytes = %10u\n",
- (unsigned int)(max_total_mem));
- fprintf(stderr, "system bytes = %10u\n",
- (unsigned int)(sbrked_mem + mmapped_mem));
- fprintf(stderr, "in use bytes = %10u\n",
- (unsigned int)(current_mallinfo.uordblks + mmapped_mem));
-#if HAVE_MMAP
- fprintf(stderr, "max mmap regions = %10u\n",
- (unsigned int)max_n_mmaps);
-#endif
-}
-
-/*
- mallinfo returns a copy of updated current mallinfo.
-*/
-
-struct mallinfo mALLINFo()
-{
- malloc_update_mallinfo();
- return current_mallinfo;
-}
-
-
-\f
-
-/*
- 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:
-
- V2.6.3 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.)
-
-*/
-
-
+/*__cplusplus*/
projects / thirdparty / squid.git / commitdiff
