dlmalloc.c

cygwin, 著名的在win32下模拟unix操作系统的东东

#endif

/*
    M_TOP_PAD is the amount of extra `padding' space to allocate or
      retain whenever sbrk is called. It is used in two ways internally:

      * When sbrk is called to extend the top of the arena to satisfy
	a new malloc request, this much padding is added to the sbrk
	request.

      * When malloc_trim is called automatically from free(),
	it is used as the `pad' argument.

      In both cases, the actual amount of padding is rounded
      so that the end of the arena is always a system page boundary.

      The main reason for using padding is to avoid calling sbrk so
      often. Having even a small pad greatly reduces the likelihood
      that nearly every malloc request during program start-up (or
      after trimming) will invoke sbrk, which needlessly wastes
      time.

      Automatic rounding-up to page-size units is normally sufficient
      to avoid measurable overhead, so the default is 0.  However, in
      systems where sbrk is relatively slow, it can pay to increase
      this value, at the expense of carrying around more memory than
      the program needs.

*/


#ifndef DEFAULT_MMAP_THRESHOLD
#define DEFAULT_MMAP_THRESHOLD (128 * 1024)
#endif

/*

    M_MMAP_THRESHOLD is the request size threshold for using mmap()
      to service a request. Requests of at least this size that cannot
      be allocated using already-existing space will be serviced via mmap.
      (If enough normal freed space already exists it is used instead.)

      Using mmap segregates relatively large chunks of memory so that
      they can be individually obtained and released from the host
      system. A request serviced through mmap is never reused by any
      other request (at least not directly; the system may just so
      happen to remap successive requests to the same locations).

      Segregating space in this way has the benefit that mmapped space
      can ALWAYS be individually released back to the system, which
      helps keep the system level memory demands of a long-lived
      program low. Mapped memory can never become `locked' between
      other chunks, as can happen with normally allocated chunks, which
      menas that even trimming via malloc_trim would not release them.

      However, it has the disadvantages that:

	 1. The space cannot be reclaimed, consolidated, and then
	    used to service later requests, as happens with normal chunks.
	 2. It can lead to more wastage because of mmap page alignment
	    requirements
	 3. It causes malloc performance to be more dependent on host
	    system memory management support routines which may vary in
	    implementation quality and may impose arbitrary
	    limitations. Generally, servicing a request via normal
	    malloc steps is faster than going through a system's mmap.

      All together, these considerations should lead you to use mmap
      only for relatively large requests.


*/



#ifndef DEFAULT_MMAP_MAX
#if HAVE_MMAP
#define DEFAULT_MMAP_MAX       (64)
#else
#define DEFAULT_MMAP_MAX       (0)
#endif
#endif

/*
    M_MMAP_MAX is the maximum number of requests to simultaneously
      service using mmap. This parameter exists because:

	 1. Some systems have a limited number of internal tables for
	    use by mmap.
	 2. In most systems, overreliance on mmap can degrade overall
	    performance.
	 3. If a program allocates many large regions, it is probably
	    better off using normal sbrk-based allocation routines that
	    can reclaim and reallocate normal heap memory. Using a
	    small value allows transition into this mode after the
	    first few allocations.

      Setting to 0 disables all use of mmap.  If HAVE_MMAP is not set,
      the default value is 0, and attempts to set it to non-zero values
      in mallopt will fail.
*/




/*

  Special defines for linux libc

  Except when compiled using these special defines for Linux libc
  using weak aliases, this malloc is NOT designed to work in
  multithreaded applications.  No semaphores or other concurrency
  control are provided to ensure that multiple malloc or free calls
  don't run at the same time, which could be disasterous. A single
  semaphore could be used across malloc, realloc, and free (which is
  essentially the effect of the linux weak alias approach). It would
  be hard to obtain finer granularity.

*/


#ifdef INTERNAL_LINUX_C_LIB

#if __STD_C

Void_t * __default_morecore_init (ptrdiff_t);
Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init;

#else

Void_t * __default_morecore_init ();
Void_t *(*__morecore)() = __default_morecore_init;

#endif

#define MORECORE (*__morecore)
#define MORECORE_FAILURE 0
#define MORECORE_CLEARS 1

#else /* INTERNAL_LINUX_C_LIB */

#if __STD_C
/* extern Void_t*     sbrk(ptrdiff_t);*/
#else
extern Void_t*     sbrk();
#endif

#ifndef MORECORE
#define MORECORE sbrk
#endif

#ifndef MORECORE_FAILURE
#define MORECORE_FAILURE -1
#endif

#ifndef MORECORE_CLEARS
#define MORECORE_CLEARS 0
#endif

#endif /* INTERNAL_LINUX_C_LIB */

#if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__)

#define cALLOc		__libc_calloc
#define fREe		__libc_free
#define mALLOc		__libc_malloc
#define mEMALIGn	__libc_memalign
#define rEALLOc		__libc_realloc
#define vALLOc		__libc_valloc
#define pvALLOc		__libc_pvalloc
#define mALLINFo	__libc_mallinfo
#define mALLOPt		__libc_mallopt

#pragma weak calloc = __libc_calloc
#pragma weak free = __libc_free
#pragma weak cfree = __libc_free
#pragma weak malloc = __libc_malloc
#pragma weak memalign = __libc_memalign
#pragma weak realloc = __libc_realloc
#pragma weak valloc = __libc_valloc
#pragma weak pvalloc = __libc_pvalloc
#pragma weak mallinfo = __libc_mallinfo
#pragma weak mallopt = __libc_mallopt

#else

#ifndef cALLOc
#define cALLOc		calloc
#endif
#ifndef fREe
#define fREe		free
#endif
#ifndef mALLOc
#define mALLOc		malloc
#endif
#ifndef mEMALIGn
#define mEMALIGn	memalign
#endif
#ifndef rEALLOc
#define rEALLOc		realloc
#endif
#ifndef vALLOc
#define vALLOc		valloc
#endif
#ifndef pvALLOc
#define pvALLOc		pvalloc
#endif
#ifndef mALLINFo
#define mALLINFo	mallinfo
#endif
#ifndef mALLOPt
#define mALLOPt		mallopt
#endif

#endif

/* Public routines */

#ifdef DEBUG2
#define malloc(size)		malloc_dbg(size, __FILE__, __LINE__)
#define free(p)			free_dbg(p, __FILE__, __LINE__)
#define realloc(p, size)	realloc_dbg(p, size, __FILE__, __LINE__)
#define calloc(n, size)		calloc_dbg(n, size, __FILE__, __LINE__)
#define memalign(align, size)	memalign_dbg(align, size, __FILE__, __LINE__)
#define valloc(size)		valloc_dbg(size, __FILE__, __LINE__)
#define pvalloc(size)		pvalloc_dbg(size, __FILE__, __LINE__)
#define cfree(p)		cfree_dbg(p, __FILE__, __LINE__)
#define malloc_trim(pad)	malloc_trim_dbg(pad, __FILE__, __LINE__)
#define malloc_usable_size(p)	malloc_usable_size_dbg(p, __FILE__, __LINE__)
#define malloc_stats(void)	malloc_stats_dbg(__FILE__, __LINE__)
#define mallopt(flag, val)	mallopt_dbg(flag, val, __FILE__, __LINE__)
#define mallinfo(void)		mallinfo_dbg(__FILE__, __LINE__)

#if __STD_C
Void_t* malloc_dbg(size_t, const char *, int);
void    free_dbg(Void_t*, const char *, int);
Void_t* realloc_dbg(Void_t*, size_t, const char *, int);
Void_t* calloc_dbg(size_t, size_t, const char *, int);
Void_t* memalign_dbg(size_t, size_t, const char *, int);
Void_t* valloc_dbg(size_t, const char *, int);
Void_t* pvalloc_dbg(size_t, const char *, int);
void    cfree_dbg(Void_t*, const char *, int);
int     malloc_trim_dbg(size_t, const char *, int);
size_t  malloc_usable_size_dbg(Void_t*, const char *, int);
void    malloc_stats_dbg(const char *, int);
int     mallopt_dbg(int, int, const char *, int);
struct mallinfo mallinfo_dbg(const char *, int);
#else
Void_t* malloc_dbg();
void    free_dbg();
Void_t* realloc_dbg();
Void_t* calloc_dbg();
Void_t* memalign_dbg();
Void_t* valloc_dbg();
Void_t* pvalloc_dbg();
void    cfree_dbg();
int     malloc_trim_dbg();
size_t  malloc_usable_size_dbg();
void    malloc_stats_dbg();
int     mallopt_dbg();
struct mallinfo mallinfo_dbg();
#endif   /* !__STD_C */

#else   /* !DEBUG2 */

#if __STD_C

Void_t* mALLOc(size_t);
void    fREe(Void_t*);
Void_t* rEALLOc(Void_t*, size_t);
Void_t* cALLOc(size_t, size_t);
Void_t* mEMALIGn(size_t, size_t);
Void_t* vALLOc(size_t);
Void_t* pvALLOc(size_t);
void    cfree(Void_t*);
int     malloc_trim(size_t);
size_t  malloc_usable_size(Void_t*);
void    malloc_stats(void);
int     mALLOPt(int, int);
struct mallinfo mALLINFo(void);
#else
Void_t* mALLOc();
void    fREe();
Void_t* rEALLOc();
Void_t* cALLOc();
Void_t* mEMALIGn();
Void_t* vALLOc();
Void_t* pvALLOc();
void    cfree();
int     malloc_trim();
size_t  malloc_usable_size();
void    malloc_stats();
int     mALLOPt();
struct mallinfo mALLINFo();
#endif
#endif   /* !DEBUG2 */

#ifdef __cplusplus
};  /* end of extern "C" */
#endif

/* ---------- To make a malloc.h, end cutting here ------------ */

#ifdef DEBUG2

#ifdef __cplusplus
extern "C" {
#endif

#undef malloc
#undef free
#undef realloc
#undef calloc
#undef memalign
#undef valloc
#undef pvalloc
#undef cfree
#undef malloc_trim
#undef malloc_usable_size
#undef malloc_stats
#undef mallopt
#undef mallinfo

#if __STD_C
Void_t* mALLOc(size_t);
void    fREe(Void_t*);
Void_t* rEALLOc(Void_t*, size_t);
Void_t* cALLOc(size_t, size_t);
Void_t* mEMALIGn(size_t, size_t);
Void_t* vALLOc(size_t);
Void_t* pvALLOc(size_t);
void    cfree(Void_t*);
int     malloc_trim(size_t);
size_t  malloc_usable_size(Void_t*);
void    malloc_stats(void);
int     mALLOPt(int, int);
struct mallinfo mALLINFo(void);
#else
Void_t* mALLOc();
void    fREe();
Void_t* rEALLOc();
Void_t* cALLOc();
Void_t* mEMALIGn();
Void_t* vALLOc();
Void_t* pvALLOc();
void    cfree();
int     malloc_trim();
size_t  malloc_usable_size();
void    malloc_stats();
int     mALLOPt();
struct mallinfo mALLINFo();
#endif

#include <ctype.h>			/* isprint() */
#ifdef DEBUG3
#include <stdlib.h>			/* atexit() */
#endif

#ifdef __cplusplus
};  /* end of extern "C" */
#endif

#endif   /* DEBUG2 */

/*
  Emulation of sbrk for WIN32
  All code within the ifdef WIN32 is untested by me.
*/


#ifdef WIN32

#define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \
			~(malloc_getpagesize-1))

/* resrve 64MB to insure large contiguous space */
#define RESERVED_SIZE (1024*1024*64)
#define NEXT_SIZE (2048*1024)
#define TOP_MEMORY ((unsigned long)2*1024*1024*1024)

struct GmListElement;
typedef struct GmListElement GmListElement;

struct GmListElement
{
	GmListElement* next;
	void* base;
};

static GmListElement* head = 0;
static unsigned int gNextAddress = 0;
static unsigned int gAddressBase = 0;
static unsigned int gAllocatedSize = 0;