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Armin's patch to prevent overflows.

This commit is contained in:
Raymond Hettinger 2004-10-06 17:51:54 +00:00
parent f7948c25a2
commit c5fa992069
1 changed files with 22 additions and 7 deletions
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29
Modules/collectionsmodule.c
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@ -52,8 +52,21 @@ typedef struct BLOCK {
} block;
static block *
newblock(block *leftlink, block *rightlink) {
block *b = PyMem_Malloc(sizeof(block));
newblock(block *leftlink, block *rightlink, int len) {
block *b;
/* To prevent len from overflowing INT_MAX on 64-bit machines, we
* refuse to allocate new blocks if the current len is dangerously
* close. There is some extra margin to prevent spurious arithmetic
* overflows at various places. The following check ensures that
* the blocks allocated to the deque, in the worst case, can only
* have INT_MAX-2 entries in total.
*/
if (len >= INT_MAX - 2*BLOCKLEN) {
PyErr_SetString(PyExc_OverflowError,
"cannot add more blocks to the deque");
return NULL;
}
b = PyMem_Malloc(sizeof(block));
if (b == NULL) {
PyErr_NoMemory();
return NULL;
@ -87,7 +100,7 @@ deque_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
if (deque == NULL)
return NULL;
b = newblock(NULL, NULL);
b = newblock(NULL, NULL, 0);
if (b == NULL) {
Py_DECREF(deque);
return NULL;
@ -110,7 +123,7 @@ deque_append(dequeobject *deque, PyObject *item)
{
deque->state++;
if (deque->rightindex == BLOCKLEN-1) {
block *b = newblock(deque->rightblock, NULL);
block *b = newblock(deque->rightblock, NULL, deque->len);
if (b == NULL)
return NULL;
assert(deque->rightblock->rightlink == NULL);
@ -132,7 +145,7 @@ deque_appendleft(dequeobject *deque, PyObject *item)
{
deque->state++;
if (deque->leftindex == 0) {
block *b = newblock(NULL, deque->leftblock);
block *b = newblock(NULL, deque->leftblock, deque->len);
if (b == NULL)
return NULL;
assert(deque->leftblock->leftlink == NULL);
@ -235,7 +248,8 @@ deque_extend(dequeobject *deque, PyObject *iterable)
while ((item = PyIter_Next(it)) != NULL) {
deque->state++;
if (deque->rightindex == BLOCKLEN-1) {
block *b = newblock(deque->rightblock, NULL);
block *b = newblock(deque->rightblock, NULL,
deque->len);
if (b == NULL) {
Py_DECREF(item);
Py_DECREF(it);
@ -271,7 +285,8 @@ deque_extendleft(dequeobject *deque, PyObject *iterable)
while ((item = PyIter_Next(it)) != NULL) {
deque->state++;
if (deque->leftindex == 0) {
block *b = newblock(NULL, deque->leftblock);
block *b = newblock(NULL, deque->leftblock,
deque->len);
if (b == NULL) {
Py_DECREF(item);
Py_DECREF(it);