mirror of https://github.com/python/cpython
129 lines
2.7 KiB
C
129 lines
2.7 KiB
C
#include "Python.h"
|
|
#include "pyarena.h"
|
|
|
|
/* An arena list is a linked list that can store either pointers or
|
|
PyObjects. The type is clear from context.
|
|
*/
|
|
|
|
typedef struct _arena_list {
|
|
struct _arena_list *al_next;
|
|
void *al_pointer;
|
|
} PyArenaList;
|
|
|
|
/* There are two linked lists in an arena, one for malloc pointers and
|
|
one for PyObject. For each list, there is a pointer to the head
|
|
and to the tail. The head is used to free the list. The tail is
|
|
used to add a new element to the list.
|
|
|
|
The list always keeps one un-used node at the end of the list.
|
|
*/
|
|
|
|
struct _arena {
|
|
PyArenaList *a_malloc_head;
|
|
PyArenaList *a_malloc_tail;
|
|
PyArenaList *a_object_head;
|
|
PyArenaList *a_object_tail;
|
|
};
|
|
|
|
static PyArenaList*
|
|
PyArenaList_New(void)
|
|
{
|
|
PyArenaList *alist = (PyArenaList *)malloc(sizeof(PyArenaList));
|
|
if (!alist)
|
|
return NULL;
|
|
|
|
alist->al_next = NULL;
|
|
alist->al_pointer = NULL;
|
|
return alist;
|
|
}
|
|
|
|
static void
|
|
PyArenaList_FreeObject(PyArenaList *alist)
|
|
{
|
|
while (alist) {
|
|
PyArenaList *prev;
|
|
Py_XDECREF((PyObject *)alist->al_pointer);
|
|
alist->al_pointer = NULL;
|
|
prev = alist;
|
|
alist = alist->al_next;
|
|
free(prev);
|
|
}
|
|
}
|
|
|
|
static void
|
|
PyArenaList_FreeMalloc(PyArenaList *alist)
|
|
{
|
|
while (alist) {
|
|
PyArenaList *prev;
|
|
if (alist->al_pointer) {
|
|
free(alist->al_pointer);
|
|
}
|
|
alist->al_pointer = NULL;
|
|
prev = alist;
|
|
alist = alist->al_next;
|
|
free(prev);
|
|
}
|
|
}
|
|
|
|
|
|
PyArena *
|
|
PyArena_New()
|
|
{
|
|
PyArena* arena = (PyArena *)malloc(sizeof(PyArena));
|
|
if (!arena)
|
|
return NULL;
|
|
|
|
arena->a_object_head = PyArenaList_New();
|
|
arena->a_object_tail = arena->a_object_head;
|
|
arena->a_malloc_head = PyArenaList_New();
|
|
arena->a_malloc_tail = arena->a_malloc_head;
|
|
return arena;
|
|
}
|
|
|
|
void
|
|
PyArena_Free(PyArena *arena)
|
|
{
|
|
assert(arena);
|
|
PyArenaList_FreeObject(arena->a_object_head);
|
|
PyArenaList_FreeMalloc(arena->a_malloc_head);
|
|
free(arena);
|
|
}
|
|
|
|
void *
|
|
PyArena_Malloc(PyArena *arena, size_t size)
|
|
{
|
|
/* A better implementation might actually use an arena. The current
|
|
approach is just a trivial implementation of the API that allows
|
|
it to be tested.
|
|
*/
|
|
void *p;
|
|
assert(size != 0);
|
|
p = malloc(size);
|
|
if (p)
|
|
PyArena_AddMallocPointer(arena, p);
|
|
return p;
|
|
}
|
|
|
|
int
|
|
PyArena_AddMallocPointer(PyArena *arena, void *pointer)
|
|
{
|
|
PyArenaList *tail = arena->a_malloc_tail;
|
|
assert(pointer);
|
|
assert(tail->al_pointer != pointer);
|
|
tail->al_next = PyArenaList_New();
|
|
tail->al_pointer = pointer;
|
|
arena->a_malloc_tail = tail->al_next;
|
|
return 1;
|
|
}
|
|
|
|
int
|
|
PyArena_AddPyObject(PyArena *arena, PyObject *pointer)
|
|
{
|
|
PyArenaList *tail = arena->a_object_tail;
|
|
assert(pointer);
|
|
tail->al_next = PyArenaList_New();
|
|
tail->al_pointer = pointer;
|
|
arena->a_object_tail = tail->al_next;
|
|
return 1;
|
|
}
|