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