Issue 16398: Use memcpy() in deque.rotate().

This commit is contained in:
Raymond Hettinger 2013-02-02 09:56:08 -08:00
parent fc23ec62a6
commit 21777acd68
1 changed files with 63 additions and 53 deletions

View File

@ -413,9 +413,8 @@ deque_inplace_concat(dequeobject *deque, PyObject *other)
static int
_deque_rotate(dequeobject *deque, Py_ssize_t n)
{
Py_ssize_t i, len=deque->len, halflen=(len+1)>>1;
PyObject *item;
block *prevblock, *leftblock, *rightblock;
Py_ssize_t i, m, len=deque->len, halflen=(len+1)>>1;
block *prevblock;
if (len <= 1)
return 0;
@ -429,64 +428,75 @@ _deque_rotate(dequeobject *deque, Py_ssize_t n)
assert(deque->len > 1);
deque->state++;
leftblock = deque->leftblock;
rightblock = deque->rightblock;
for (i=0 ; i<n ; i++) {
item = rightblock->data[deque->rightindex];
assert (item != NULL);
deque->rightindex--;
if (deque->rightindex == -1) {
assert(rightblock != NULL);
prevblock = rightblock->leftlink;
assert(leftblock != rightblock);
freeblock(rightblock);
prevblock->rightlink = NULL;
deque->rightblock = rightblock = prevblock;
deque->rightindex = BLOCKLEN - 1;
}
for (i=0 ; i<n ; ) {
if (deque->leftindex == 0) {
block *b = newblock(NULL, leftblock, deque->len);
if (b == NULL) {
deque->len--;
Py_DECREF(item);
block *b = newblock(NULL, deque->leftblock, deque->len);
if (b == NULL)
return -1;
}
assert(leftblock->leftlink == NULL);
leftblock->leftlink = b;
deque->leftblock = leftblock = b;
assert(deque->leftblock->leftlink == NULL);
deque->leftblock->leftlink = b;
deque->leftblock = b;
deque->leftindex = BLOCKLEN;
}
deque->leftindex--;
leftblock->data[deque->leftindex] = item;
assert(deque->leftindex > 0);
m = n - i;
if (m > deque->rightindex + 1)
m = deque->rightindex + 1;
if (m > deque->leftindex)
m = deque->leftindex;
assert (m > 0);
memcpy(&deque->leftblock->data[deque->leftindex - m],
&deque->rightblock->data[deque->rightindex - m + 1],
m * sizeof(PyObject *));
deque->rightindex -= m;
deque->leftindex -= m;
i += m;
if (deque->rightindex == -1) {
assert(deque->rightblock != NULL);
prevblock = deque->rightblock->leftlink;
assert(deque->leftblock != deque->rightblock);
freeblock(deque->rightblock);
prevblock->rightlink = NULL;
deque->rightblock = prevblock;
deque->rightindex = BLOCKLEN - 1;
}
for (i=0 ; i>n ; i--) {
assert(leftblock != NULL);
item = leftblock->data[deque->leftindex];
assert (item != NULL);
deque->leftindex++;
if (deque->leftindex == BLOCKLEN) {
assert(leftblock != rightblock);
prevblock = leftblock->rightlink;
freeblock(leftblock);
assert(prevblock != NULL);
prevblock->leftlink = NULL;
deque->leftblock = leftblock = prevblock;
deque->leftindex = 0;
}
for (i=0 ; i>n ; ) {
if (deque->rightindex == BLOCKLEN - 1) {
block *b = newblock(rightblock, NULL, deque->len);
if (b == NULL) {
deque->len--;
Py_DECREF(item);
block *b = newblock(deque->rightblock, NULL, deque->len);
if (b == NULL)
return -1;
}
assert(rightblock->rightlink == NULL);
rightblock->rightlink = b;
deque->rightblock = rightblock = b;
assert(deque->rightblock->rightlink == NULL);
deque->rightblock->rightlink = b;
deque->rightblock = b;
deque->rightindex = -1;
}
deque->rightindex++;
rightblock->data[deque->rightindex] = item;
assert (deque->rightindex < BLOCKLEN - 1);
m = i - n;
if (m > BLOCKLEN - deque->leftindex)
m = BLOCKLEN - deque->leftindex;
if (m > BLOCKLEN - 1 - deque->rightindex)
m = BLOCKLEN - 1 - deque->rightindex;
assert (m > 0);
memcpy(&deque->rightblock->data[deque->rightindex + 1],
&deque->leftblock->data[deque->leftindex],
m * sizeof(PyObject *));
deque->leftindex += m;
deque->rightindex += m;
i -= m;
if (deque->leftindex == BLOCKLEN) {
assert(deque->leftblock != deque->rightblock);
prevblock = deque->leftblock->rightlink;
freeblock(deque->leftblock);
assert(prevblock != NULL);
prevblock->leftlink = NULL;
deque->leftblock = prevblock;
deque->leftindex = 0;
}
}
return 0;
}