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#include <Python.h>
#include <ffi.h>
#ifdef MS_WIN32
#include <windows.h>
#else
#include <sys/mman.h>
#include <unistd.h>
# if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
# define MAP_ANONYMOUS MAP_ANON
# endif
#endif
#include "ctypes.h"
/* BLOCKSIZE can be adjusted. Larger blocksize will take a larger memory
overhead, but allocate less blocks from the system. It may be that some
systems have a limit of how many mmap'd blocks can be open.
*/
#define BLOCKSIZE _pagesize
/* #define MALLOC_CLOSURE_DEBUG */ /* enable for some debugging output */
/******************************************************************/
typedef union _tagITEM {
ffi_closure closure;
union _tagITEM *next;
} ITEM;
static ITEM *free_list;
static int _pagesize;
static void more_core(void)
{
ITEM *item;
int count, i;
/* determine the pagesize */
#ifdef MS_WIN32
if (!_pagesize) {
SYSTEM_INFO systeminfo;
GetSystemInfo(&systeminfo);
_pagesize = systeminfo.dwPageSize;
}
#else
if (!_pagesize) {
#ifdef _SC_PAGESIZE
_pagesize = sysconf(_SC_PAGESIZE);
#else
_pagesize = getpagesize();
#endif
}
#endif
/* calculate the number of nodes to allocate */
count = BLOCKSIZE / sizeof(ITEM);
/* allocate a memory block */
#ifdef MS_WIN32
item = (ITEM *)VirtualAlloc(NULL,
count * sizeof(ITEM),
MEM_COMMIT,
PAGE_EXECUTE_READWRITE);
if (item == NULL)
return;
#else
item = (ITEM *)mmap(NULL,
count * sizeof(ITEM),
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS,
-1,
0);
if (item == (void *)MAP_FAILED)
return;
#endif
#ifdef MALLOC_CLOSURE_DEBUG
printf("block at %p allocated (%d bytes), %d ITEMs\n",
item, count * (int)sizeof(ITEM), count);
#endif
/* put them into the free list */
for (i = 0; i < count; ++i) {
item->next = free_list;
free_list = item;
++item;
}
}
/******************************************************************/
/* put the item back into the free list */
void ffi_closure_free(void *p)
{
ITEM *item = (ITEM *)p;
item->next = free_list;
free_list = item;
}
/* return one item from the free list, allocating more if needed */
void *ffi_closure_alloc(size_t ignored, void** codeloc)
{
ITEM *item;
if (!free_list)
more_core();
if (!free_list)
return NULL;
item = free_list;
free_list = item->next;
#ifdef _M_ARM
// set Thumb bit so that blx is called correctly
*codeloc = (ITEM*)((uintptr_t)item | 1);
#else
*codeloc = (void *)item;
#endif
return (void *)item;
}
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