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cpython/Modules/_collectionsmodule.c

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#include "Python.h"
#include "structmember.h"
/* collections module implementation of a deque() datatype
Written and maintained by Raymond D. Hettinger <python@rcn.com>
Copyright (c) 2004 Python Software Foundation.
All rights reserved.
*/
/* The block length may be set to any number over 1. Larger numbers
* reduce the number of calls to the memory allocator but take more
* memory. Ideally, BLOCKLEN should be set with an eye to the
* length of a cache line.
*/
#define BLOCKLEN 62
#define CENTER ((BLOCKLEN - 1) / 2)
/* A `dequeobject` is composed of a doubly-linked list of `block` nodes.
* This list is not circular (the leftmost block has leftlink==NULL,
* and the rightmost block has rightlink==NULL). A deque d's first
* element is at d.leftblock[leftindex] and its last element is at
* d.rightblock[rightindex]; note that, unlike as for Python slice
* indices, these indices are inclusive on both ends. By being inclusive
* on both ends, algorithms for left and right operations become
* symmetrical which simplifies the design.
*
* The list of blocks is never empty, so d.leftblock and d.rightblock
* are never equal to NULL.
*
* The indices, d.leftindex and d.rightindex are always in the range
* 0 <= index < BLOCKLEN.
* Their exact relationship is:
* (d.leftindex + d.len - 1) % BLOCKLEN == d.rightindex.
*
* Empty deques have d.len == 0; d.leftblock==d.rightblock;
* d.leftindex == CENTER+1; and d.rightindex == CENTER.
* Checking for d.len == 0 is the intended way to see whether d is empty.
*
* Whenever d.leftblock == d.rightblock,
* d.leftindex + d.len - 1 == d.rightindex.
*
* However, when d.leftblock != d.rightblock, d.leftindex and d.rightindex
* become indices into distinct blocks and either may be larger than the
* other.
*/
typedef struct BLOCK {
struct BLOCK *leftlink;
struct BLOCK *rightlink;
PyObject *data[BLOCKLEN];
} block;
#define MAXFREEBLOCKS 10
static Py_ssize_t numfreeblocks = 0;
static block *freeblocks[MAXFREEBLOCKS];
static block *
newblock(block *leftlink, block *rightlink, Py_ssize_t len) {
block *b;
/* To prevent len from overflowing PY_SSIZE_T_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 PY_SSIZE_T_MAX-2 entries in total.
*/
if (len >= PY_SSIZE_T_MAX - 2*BLOCKLEN) {
PyErr_SetString(PyExc_OverflowError,
"cannot add more blocks to the deque");
return NULL;
}
if (numfreeblocks) {
numfreeblocks -= 1;
b = freeblocks[numfreeblocks];
} else {
b = PyMem_Malloc(sizeof(block));
if (b == NULL) {
PyErr_NoMemory();
return NULL;
}
}
b->leftlink = leftlink;
b->rightlink = rightlink;
return b;
}
static void
freeblock(block *b)
{
if (numfreeblocks < MAXFREEBLOCKS) {
freeblocks[numfreeblocks] = b;
numfreeblocks++;
} else {
PyMem_Free(b);
}
}
typedef struct {
PyObject_HEAD
block *leftblock;
block *rightblock;
Py_ssize_t leftindex; /* in range(BLOCKLEN) */
Py_ssize_t rightindex; /* in range(BLOCKLEN) */
Py_ssize_t len;
Py_ssize_t maxlen;
long state; /* incremented whenever the indices move */
PyObject *weakreflist; /* List of weak references */
} dequeobject;
/* The deque's size limit is d.maxlen. The limit can be zero or positive.
* If there is no limit, then d.maxlen == -1.
*
* After an item is added to a deque, we check to see if the size has grown past
* the limit. If it has, we get the size back down to the limit by popping an
* item off of the opposite end. The methods that can trigger this are append(),
* appendleft(), extend(), and extendleft().
*/
#define TRIM(d, popfunction) \
if (d->maxlen != -1 && d->len > d->maxlen) { \
PyObject *rv = popfunction(d, NULL); \
assert(rv != NULL && d->len <= d->maxlen); \
Py_DECREF(rv); \
}
static PyTypeObject deque_type;
static PyObject *
deque_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
dequeobject *deque;
block *b;
/* create dequeobject structure */
deque = (dequeobject *)type->tp_alloc(type, 0);
if (deque == NULL)
return NULL;
b = newblock(NULL, NULL, 0);
if (b == NULL) {
Py_DECREF(deque);
return NULL;
}
assert(BLOCKLEN >= 2);
deque->leftblock = b;
deque->rightblock = b;
deque->leftindex = CENTER + 1;
deque->rightindex = CENTER;
deque->len = 0;
deque->state = 0;
deque->weakreflist = NULL;
deque->maxlen = -1;
return (PyObject *)deque;
}
static PyObject *
deque_pop(dequeobject *deque, PyObject *unused)
{
PyObject *item;
block *prevblock;
if (deque->len == 0) {
PyErr_SetString(PyExc_IndexError, "pop from an empty deque");
return NULL;
}
item = deque->rightblock->data[deque->rightindex];
deque->rightindex--;
deque->len--;
deque->state++;
if (deque->rightindex == -1) {
if (deque->len == 0) {
assert(deque->leftblock == deque->rightblock);
assert(deque->leftindex == deque->rightindex+1);
/* re-center instead of freeing a block */
deque->leftindex = CENTER + 1;
deque->rightindex = CENTER;
} else {
prevblock = deque->rightblock->leftlink;
assert(deque->leftblock != deque->rightblock);
freeblock(deque->rightblock);
prevblock->rightlink = NULL;
deque->rightblock = prevblock;
deque->rightindex = BLOCKLEN - 1;
}
}
return item;
}
PyDoc_STRVAR(pop_doc, "Remove and return the rightmost element.");
static PyObject *
deque_popleft(dequeobject *deque, PyObject *unused)
{
PyObject *item;
block *prevblock;
if (deque->len == 0) {
PyErr_SetString(PyExc_IndexError, "pop from an empty deque");
return NULL;
}
assert(deque->leftblock != NULL);
item = deque->leftblock->data[deque->leftindex];
deque->leftindex++;
deque->len--;
deque->state++;
if (deque->leftindex == BLOCKLEN) {
if (deque->len == 0) {
assert(deque->leftblock == deque->rightblock);
assert(deque->leftindex == deque->rightindex+1);
/* re-center instead of freeing a block */
deque->leftindex = CENTER + 1;
deque->rightindex = CENTER;
} else {
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 item;
}
PyDoc_STRVAR(popleft_doc, "Remove and return the leftmost element.");
static PyObject *
deque_append(dequeobject *deque, PyObject *item)
{
deque->state++;
if (deque->rightindex == BLOCKLEN-1) {
block *b = newblock(deque->rightblock, NULL, deque->len);
if (b == NULL)
return NULL;
assert(deque->rightblock->rightlink == NULL);
deque->rightblock->rightlink = b;
deque->rightblock = b;
deque->rightindex = -1;
}
Py_INCREF(item);
deque->len++;
deque->rightindex++;
deque->rightblock->data[deque->rightindex] = item;
TRIM(deque, deque_popleft);
Py_RETURN_NONE;
}
PyDoc_STRVAR(append_doc, "Add an element to the right side of the deque.");
static PyObject *
deque_appendleft(dequeobject *deque, PyObject *item)
{
deque->state++;
if (deque->leftindex == 0) {
block *b = newblock(NULL, deque->leftblock, deque->len);
if (b == NULL)
return NULL;
assert(deque->leftblock->leftlink == NULL);
deque->leftblock->leftlink = b;
deque->leftblock = b;
deque->leftindex = BLOCKLEN;
}
Py_INCREF(item);
deque->len++;
deque->leftindex--;
deque->leftblock->data[deque->leftindex] = item;
TRIM(deque, deque_pop);
Py_RETURN_NONE;
}
PyDoc_STRVAR(appendleft_doc, "Add an element to the left side of the deque.");
/* Run an iterator to exhaustion. Shortcut for
the extend/extendleft methods when maxlen == 0. */
static PyObject*
consume_iterator(PyObject *it)
{
PyObject *item;
while ((item = PyIter_Next(it)) != NULL) {
Py_DECREF(item);
}
Py_DECREF(it);
if (PyErr_Occurred())
return NULL;
Py_RETURN_NONE;
}
static PyObject *
deque_extend(dequeobject *deque, PyObject *iterable)
{
PyObject *it, *item;
/* Handle case where id(deque) == id(iterable) */
if ((PyObject *)deque == iterable) {
PyObject *result;
PyObject *s = PySequence_List(iterable);
if (s == NULL)
return NULL;
result = deque_extend(deque, s);
Py_DECREF(s);
return result;
}
it = PyObject_GetIter(iterable);
if (it == NULL)
return NULL;
if (deque->maxlen == 0)
return consume_iterator(it);
while ((item = PyIter_Next(it)) != NULL) {
deque->state++;
if (deque->rightindex == BLOCKLEN-1) {
block *b = newblock(deque->rightblock, NULL,
deque->len);
if (b == NULL) {
Py_DECREF(item);
Py_DECREF(it);
return NULL;
}
assert(deque->rightblock->rightlink == NULL);
deque->rightblock->rightlink = b;
deque->rightblock = b;
deque->rightindex = -1;
}
deque->len++;
deque->rightindex++;
deque->rightblock->data[deque->rightindex] = item;
TRIM(deque, deque_popleft);
}
Py_DECREF(it);
if (PyErr_Occurred())
return NULL;
Py_RETURN_NONE;
}
PyDoc_STRVAR(extend_doc,
"Extend the right side of the deque with elements from the iterable");
static PyObject *
deque_extendleft(dequeobject *deque, PyObject *iterable)
{
PyObject *it, *item;
/* Handle case where id(deque) == id(iterable) */
if ((PyObject *)deque == iterable) {
PyObject *result;
PyObject *s = PySequence_List(iterable);
if (s == NULL)
return NULL;
result = deque_extendleft(deque, s);
Py_DECREF(s);
return result;
}
it = PyObject_GetIter(iterable);
if (it == NULL)
return NULL;
if (deque->maxlen == 0)
return consume_iterator(it);
while ((item = PyIter_Next(it)) != NULL) {
deque->state++;
if (deque->leftindex == 0) {
block *b = newblock(NULL, deque->leftblock,
deque->len);
if (b == NULL) {
Py_DECREF(item);
Py_DECREF(it);
return NULL;
}
assert(deque->leftblock->leftlink == NULL);
deque->leftblock->leftlink = b;
deque->leftblock = b;
deque->leftindex = BLOCKLEN;
}
deque->len++;
deque->leftindex--;
deque->leftblock->data[deque->leftindex] = item;
TRIM(deque, deque_pop);
}
Py_DECREF(it);
if (PyErr_Occurred())
return NULL;
Py_RETURN_NONE;
}
PyDoc_STRVAR(extendleft_doc,
"Extend the left side of the deque with elements from the iterable");
static PyObject *
deque_inplace_concat(dequeobject *deque, PyObject *other)
{
PyObject *result;
result = deque_extend(deque, other);
if (result == NULL)
return result;
Py_DECREF(result);
Py_INCREF(deque);
return (PyObject *)deque;
}
static int
_deque_rotate(dequeobject *deque, Py_ssize_t n)
{
Py_ssize_t i, len=deque->len, halflen=(len+1)>>1;
PyObject *item, *rv;
if (len == 0)
return 0;
if (n > halflen || n < -halflen) {
n %= len;
if (n > halflen)
n -= len;
else if (n < -halflen)
n += len;
}
for (i=0 ; i<n ; i++) {
item = deque_pop(deque, NULL);
assert (item != NULL);
rv = deque_appendleft(deque, item);
Py_DECREF(item);
if (rv == NULL)
return -1;
Py_DECREF(rv);
}
for (i=0 ; i>n ; i--) {
item = deque_popleft(deque, NULL);
assert (item != NULL);
rv = deque_append(deque, item);
Py_DECREF(item);
if (rv == NULL)
return -1;
Py_DECREF(rv);
}
return 0;
}
static PyObject *
deque_rotate(dequeobject *deque, PyObject *args)
{
Py_ssize_t n=1;
if (!PyArg_ParseTuple(args, "|n:rotate", &n))
return NULL;
if (_deque_rotate(deque, n) == 0)
Py_RETURN_NONE;
return NULL;
}
PyDoc_STRVAR(rotate_doc,
"Rotate the deque n steps to the right (default n=1). If n is negative, rotates left.");
static PyObject *
deque_reverse(dequeobject *deque, PyObject *unused)
{
block *leftblock = deque->leftblock;
block *rightblock = deque->rightblock;
Py_ssize_t leftindex = deque->leftindex;
Py_ssize_t rightindex = deque->rightindex;
Py_ssize_t n = (deque->len)/2;
Py_ssize_t i;
PyObject *tmp;
for (i=0 ; i<n ; i++) {
/* Validate that pointers haven't met in the middle */
assert(leftblock != rightblock || leftindex < rightindex);
/* Swap */
tmp = leftblock->data[leftindex];
leftblock->data[leftindex] = rightblock->data[rightindex];
rightblock->data[rightindex] = tmp;
/* Advance left block/index pair */
leftindex++;
if (leftindex == BLOCKLEN) {
if (leftblock->rightlink == NULL)
break;
leftblock = leftblock->rightlink;
leftindex = 0;
}
/* Step backwards with the right block/index pair */
rightindex--;
if (rightindex == -1) {
if (rightblock->leftlink == NULL)
break;
rightblock = rightblock->leftlink;
rightindex = BLOCKLEN - 1;
}
}
Py_RETURN_NONE;
}
PyDoc_STRVAR(reverse_doc,
"D.reverse() -- reverse *IN PLACE*");
static PyObject *
deque_count(dequeobject *deque, PyObject *v)
{
block *leftblock = deque->leftblock;
Py_ssize_t leftindex = deque->leftindex;
Py_ssize_t n = deque->len;
Py_ssize_t i;
Py_ssize_t count = 0;
PyObject *item;
long start_state = deque->state;
int cmp;
for (i=0 ; i<n ; i++) {
item = leftblock->data[leftindex];
cmp = PyObject_RichCompareBool(item, v, Py_EQ);
if (cmp > 0)
count++;
else if (cmp < 0)
return NULL;
if (start_state != deque->state) {
PyErr_SetString(PyExc_RuntimeError,
"deque mutated during iteration");
return NULL;
}
/* Advance left block/index pair */
leftindex++;
if (leftindex == BLOCKLEN) {
if (leftblock->rightlink == NULL) /* can occur when i==n-1 */
break;
leftblock = leftblock->rightlink;
leftindex = 0;
}
}
return PyLong_FromSsize_t(count);
}
PyDoc_STRVAR(count_doc,
"D.count(value) -> integer -- return number of occurrences of value");
static Py_ssize_t
deque_len(dequeobject *deque)
{
return deque->len;
}
static PyObject *
deque_remove(dequeobject *deque, PyObject *value)
{
Py_ssize_t i, n=deque->len;
for (i=0 ; i<n ; i++) {
PyObject *item = deque->leftblock->data[deque->leftindex];
int cmp = PyObject_RichCompareBool(item, value, Py_EQ);
if (deque->len != n) {
PyErr_SetString(PyExc_IndexError,
"deque mutated during remove().");
return NULL;
}
if (cmp > 0) {
PyObject *tgt = deque_popleft(deque, NULL);
assert (tgt != NULL);
Py_DECREF(tgt);
if (_deque_rotate(deque, i) == -1)
return NULL;
Py_RETURN_NONE;
}
else if (cmp < 0) {
_deque_rotate(deque, i);
return NULL;
}
_deque_rotate(deque, -1);
}
PyErr_SetString(PyExc_ValueError, "deque.remove(x): x not in deque");
return NULL;
}
PyDoc_STRVAR(remove_doc,
"D.remove(value) -- remove first occurrence of value.");
static int
deque_clear(dequeobject *deque)
{
PyObject *item;
while (deque->len) {
item = deque_pop(deque, NULL);
assert (item != NULL);
Py_DECREF(item);
}
assert(deque->leftblock == deque->rightblock &&
deque->leftindex - 1 == deque->rightindex &&
deque->len == 0);
return 0;
}
static PyObject *
deque_item(dequeobject *deque, Py_ssize_t i)
{
block *b;
PyObject *item;
Py_ssize_t n, index=i;
if (i < 0 || i >= deque->len) {
PyErr_SetString(PyExc_IndexError,
"deque index out of range");
return NULL;
}
if (i == 0) {
i = deque->leftindex;
b = deque->leftblock;
} else if (i == deque->len - 1) {
i = deque->rightindex;
b = deque->rightblock;
} else {
i += deque->leftindex;
n = i / BLOCKLEN;
i %= BLOCKLEN;
if (index < (deque->len >> 1)) {
b = deque->leftblock;
while (n--)
b = b->rightlink;
} else {
n = (deque->leftindex + deque->len - 1) / BLOCKLEN - n;
b = deque->rightblock;
while (n--)
b = b->leftlink;
}
}
item = b->data[i];
Py_INCREF(item);
return item;
}
/* delitem() implemented in terms of rotate for simplicity and reasonable
performance near the end points. If for some reason this method becomes
popular, it is not hard to re-implement this using direct data movement
(similar to code in list slice assignment) and achieve a two or threefold
performance boost.
*/
static int
deque_del_item(dequeobject *deque, Py_ssize_t i)
{
PyObject *item;
assert (i >= 0 && i < deque->len);
if (_deque_rotate(deque, -i) == -1)
return -1;
item = deque_popleft(deque, NULL);
assert (item != NULL);
Py_DECREF(item);
return _deque_rotate(deque, i);
}
static int
deque_ass_item(dequeobject *deque, Py_ssize_t i, PyObject *v)
{
PyObject *old_value;
block *b;
Py_ssize_t n, len=deque->len, halflen=(len+1)>>1, index=i;
if (i < 0 || i >= len) {
PyErr_SetString(PyExc_IndexError,
"deque index out of range");
return -1;
}
if (v == NULL)
return deque_del_item(deque, i);
i += deque->leftindex;
n = i / BLOCKLEN;
i %= BLOCKLEN;
if (index <= halflen) {
b = deque->leftblock;
while (n--)
b = b->rightlink;
} else {
n = (deque->leftindex + len - 1) / BLOCKLEN - n;
b = deque->rightblock;
while (n--)
b = b->leftlink;
}
Py_INCREF(v);
old_value = b->data[i];
b->data[i] = v;
Py_DECREF(old_value);
return 0;
}
static PyObject *
deque_clearmethod(dequeobject *deque)
{
int rv;
rv = deque_clear(deque);
assert (rv != -1);
Py_RETURN_NONE;
}
PyDoc_STRVAR(clear_doc, "Remove all elements from the deque.");
static void
deque_dealloc(dequeobject *deque)
{
PyObject_GC_UnTrack(deque);
if (deque->weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *) deque);
if (deque->leftblock != NULL) {
deque_clear(deque);
assert(deque->leftblock != NULL);
freeblock(deque->leftblock);
}
deque->leftblock = NULL;
deque->rightblock = NULL;
Py_TYPE(deque)->tp_free(deque);
}
static int
deque_traverse(dequeobject *deque, visitproc visit, void *arg)
{
block *b;
PyObject *item;
Py_ssize_t index;
Py_ssize_t indexlo = deque->leftindex;
for (b = deque->leftblock; b != NULL; b = b->rightlink) {
const Py_ssize_t indexhi = b == deque->rightblock ?
deque->rightindex :
BLOCKLEN - 1;
for (index = indexlo; index <= indexhi; ++index) {
item = b->data[index];
Py_VISIT(item);
}
indexlo = 0;
}
return 0;
}
static PyObject *
deque_copy(PyObject *deque)
{
if (((dequeobject *)deque)->maxlen == -1)
return PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "O", deque, NULL);
else
return PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "Oi",
deque, ((dequeobject *)deque)->maxlen, NULL);
}
PyDoc_STRVAR(copy_doc, "Return a shallow copy of a deque.");
static PyObject *
deque_reduce(dequeobject *deque)
{
PyObject *dict, *result, *aslist;
dict = PyObject_GetAttrString((PyObject *)deque, "__dict__");
if (dict == NULL)
PyErr_Clear();
aslist = PySequence_List((PyObject *)deque);
if (aslist == NULL) {
Py_XDECREF(dict);
return NULL;
}
if (dict == NULL) {
if (deque->maxlen == -1)
result = Py_BuildValue("O(O)", Py_TYPE(deque), aslist);
else
result = Py_BuildValue("O(On)", Py_TYPE(deque), aslist, deque->maxlen);
} else {
if (deque->maxlen == -1)
result = Py_BuildValue("O(OO)O", Py_TYPE(deque), aslist, Py_None, dict);
else
result = Py_BuildValue("O(On)O", Py_TYPE(deque), aslist, deque->maxlen, dict);
}
Py_XDECREF(dict);
Py_DECREF(aslist);
return result;
}
PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");
static PyObject *
deque_repr(PyObject *deque)
{
PyObject *aslist, *result;
int i;
i = Py_ReprEnter(deque);
if (i != 0) {
if (i < 0)
return NULL;
return PyUnicode_FromString("[...]");
}
aslist = PySequence_List(deque);
if (aslist == NULL) {
Py_ReprLeave(deque);
return NULL;
}
if (((dequeobject *)deque)->maxlen != -1)
result = PyUnicode_FromFormat("deque(%R, maxlen=%zd)",
aslist, ((dequeobject *)deque)->maxlen);
else
result = PyUnicode_FromFormat("deque(%R)", aslist);
Py_DECREF(aslist);
Py_ReprLeave(deque);
return result;
}
static PyObject *
deque_richcompare(PyObject *v, PyObject *w, int op)
{
PyObject *it1=NULL, *it2=NULL, *x, *y;
Py_ssize_t vs, ws;
int b, cmp=-1;
if (!PyObject_TypeCheck(v, &deque_type) ||
!PyObject_TypeCheck(w, &deque_type)) {
Py_RETURN_NOTIMPLEMENTED;
}
/* Shortcuts */
vs = ((dequeobject *)v)->len;
ws = ((dequeobject *)w)->len;
if (op == Py_EQ) {
if (v == w)
Py_RETURN_TRUE;
if (vs != ws)
Py_RETURN_FALSE;
}
if (op == Py_NE) {
if (v == w)
Py_RETURN_FALSE;
if (vs != ws)
Py_RETURN_TRUE;
}
/* Search for the first index where items are different */
it1 = PyObject_GetIter(v);
if (it1 == NULL)
goto done;
it2 = PyObject_GetIter(w);
if (it2 == NULL)
goto done;
for (;;) {
x = PyIter_Next(it1);
if (x == NULL && PyErr_Occurred())
goto done;
y = PyIter_Next(it2);
if (x == NULL || y == NULL)
break;
b = PyObject_RichCompareBool(x, y, Py_EQ);
if (b == 0) {
cmp = PyObject_RichCompareBool(x, y, op);
Py_DECREF(x);
Py_DECREF(y);
goto done;
}
Py_DECREF(x);
Py_DECREF(y);
if (b == -1)
goto done;
}
/* We reached the end of one deque or both */
Py_XDECREF(x);
Py_XDECREF(y);
if (PyErr_Occurred())
goto done;
switch (op) {
case Py_LT: cmp = y != NULL; break; /* if w was longer */
case Py_LE: cmp = x == NULL; break; /* if v was not longer */
case Py_EQ: cmp = x == y; break; /* if we reached the end of both */
case Py_NE: cmp = x != y; break; /* if one deque continues */
case Py_GT: cmp = x != NULL; break; /* if v was longer */
case Py_GE: cmp = y == NULL; break; /* if w was not longer */
}
done:
Py_XDECREF(it1);
Py_XDECREF(it2);
if (cmp == 1)
Py_RETURN_TRUE;
if (cmp == 0)
Py_RETURN_FALSE;
return NULL;
}
static int
deque_init(dequeobject *deque, PyObject *args, PyObject *kwdargs)
{
PyObject *iterable = NULL;
PyObject *maxlenobj = NULL;
Py_ssize_t maxlen = -1;
char *kwlist[] = {"iterable", "maxlen", 0};
if (!PyArg_ParseTupleAndKeywords(args, kwdargs, "|OO:deque", kwlist, &iterable, &maxlenobj))
return -1;
if (maxlenobj != NULL && maxlenobj != Py_None) {
maxlen = PyLong_AsSsize_t(maxlenobj);
if (maxlen == -1 && PyErr_Occurred())
return -1;
if (maxlen < 0) {
PyErr_SetString(PyExc_ValueError, "maxlen must be non-negative");
return -1;
}
}
deque->maxlen = maxlen;
deque_clear(deque);
if (iterable != NULL) {
PyObject *rv = deque_extend(deque, iterable);
if (rv == NULL)
return -1;
Py_DECREF(rv);
}
return 0;
}
static PyObject *
deque_get_maxlen(dequeobject *deque)
{
if (deque->maxlen == -1)
Py_RETURN_NONE;
return PyLong_FromSsize_t(deque->maxlen);
}
static PyGetSetDef deque_getset[] = {
{"maxlen", (getter)deque_get_maxlen, (setter)NULL,
"maximum size of a deque or None if unbounded"},
{0}
};
static PySequenceMethods deque_as_sequence = {
(lenfunc)deque_len, /* sq_length */
0, /* sq_concat */
0, /* sq_repeat */
(ssizeargfunc)deque_item, /* sq_item */
0, /* sq_slice */
(ssizeobjargproc)deque_ass_item, /* sq_ass_item */
0, /* sq_ass_slice */
0, /* sq_contains */
(binaryfunc)deque_inplace_concat, /* sq_inplace_concat */
0, /* sq_inplace_repeat */
};
/* deque object ********************************************************/
static PyObject *deque_iter(dequeobject *deque);
static PyObject *deque_reviter(dequeobject *deque);
PyDoc_STRVAR(reversed_doc,
"D.__reversed__() -- return a reverse iterator over the deque");
static PyMethodDef deque_methods[] = {
{"append", (PyCFunction)deque_append,
METH_O, append_doc},
{"appendleft", (PyCFunction)deque_appendleft,
METH_O, appendleft_doc},
{"clear", (PyCFunction)deque_clearmethod,
METH_NOARGS, clear_doc},
{"__copy__", (PyCFunction)deque_copy,
METH_NOARGS, copy_doc},
{"count", (PyCFunction)deque_count,
METH_O, count_doc},
{"extend", (PyCFunction)deque_extend,
METH_O, extend_doc},
{"extendleft", (PyCFunction)deque_extendleft,
METH_O, extendleft_doc},
{"pop", (PyCFunction)deque_pop,
METH_NOARGS, pop_doc},
{"popleft", (PyCFunction)deque_popleft,
METH_NOARGS, popleft_doc},
{"__reduce__", (PyCFunction)deque_reduce,
METH_NOARGS, reduce_doc},
{"remove", (PyCFunction)deque_remove,
METH_O, remove_doc},
{"__reversed__", (PyCFunction)deque_reviter,
METH_NOARGS, reversed_doc},
{"reverse", (PyCFunction)deque_reverse,
METH_NOARGS, reverse_doc},
{"rotate", (PyCFunction)deque_rotate,
METH_VARARGS, rotate_doc},
{NULL, NULL} /* sentinel */
};
PyDoc_STRVAR(deque_doc,
"deque(iterable[, maxlen]) --> deque object\n\
\n\
Build an ordered collection with optimized access from its endpoints.");
static PyTypeObject deque_type = {
PyVarObject_HEAD_INIT(NULL, 0)
"collections.deque", /* tp_name */
sizeof(dequeobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)deque_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
deque_repr, /* tp_repr */
0, /* tp_as_number */
&deque_as_sequence, /* tp_as_sequence */
0, /* tp_as_mapping */
PyObject_HashNotImplemented, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
/* tp_flags */
deque_doc, /* tp_doc */
(traverseproc)deque_traverse, /* tp_traverse */
(inquiry)deque_clear, /* tp_clear */
(richcmpfunc)deque_richcompare, /* tp_richcompare */
offsetof(dequeobject, weakreflist), /* tp_weaklistoffset*/
(getiterfunc)deque_iter, /* tp_iter */
0, /* tp_iternext */
deque_methods, /* tp_methods */
0, /* tp_members */
deque_getset, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
(initproc)deque_init, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
deque_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
};
/*********************** Deque Iterator **************************/
typedef struct {
PyObject_HEAD
Py_ssize_t index;
block *b;
dequeobject *deque;
long state; /* state when the iterator is created */
Py_ssize_t counter; /* number of items remaining for iteration */
} dequeiterobject;
static PyTypeObject dequeiter_type;
static PyObject *
deque_iter(dequeobject *deque)
{
dequeiterobject *it;
it = PyObject_GC_New(dequeiterobject, &dequeiter_type);
if (it == NULL)
return NULL;
it->b = deque->leftblock;
it->index = deque->leftindex;
Py_INCREF(deque);
it->deque = deque;
it->state = deque->state;
it->counter = deque->len;
PyObject_GC_Track(it);
return (PyObject *)it;
}
static int
dequeiter_traverse(dequeiterobject *dio, visitproc visit, void *arg)
{
Py_VISIT(dio->deque);
return 0;
}
static void
dequeiter_dealloc(dequeiterobject *dio)
{
Py_XDECREF(dio->deque);
PyObject_GC_Del(dio);
}
static PyObject *
dequeiter_next(dequeiterobject *it)
{
PyObject *item;
if (it->deque->state != it->state) {
it->counter = 0;
PyErr_SetString(PyExc_RuntimeError,
"deque mutated during iteration");
return NULL;
}
if (it->counter == 0)
return NULL;
assert (!(it->b == it->deque->rightblock &&
it->index > it->deque->rightindex));
item = it->b->data[it->index];
it->index++;
it->counter--;
if (it->index == BLOCKLEN && it->counter > 0) {
assert (it->b->rightlink != NULL);
it->b = it->b->rightlink;
it->index = 0;
}
Py_INCREF(item);
return item;
}
static PyObject *
dequeiter_len(dequeiterobject *it)
{
return PyLong_FromSsize_t(it->counter);
}
PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
static PyMethodDef dequeiter_methods[] = {
{"__length_hint__", (PyCFunction)dequeiter_len, METH_NOARGS, length_hint_doc},
{NULL, NULL} /* sentinel */
};
static PyTypeObject dequeiter_type = {
PyVarObject_HEAD_INIT(NULL, 0)
"deque_iterator", /* tp_name */
sizeof(dequeiterobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)dequeiter_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
0, /* tp_doc */
(traverseproc)dequeiter_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)dequeiter_next, /* tp_iternext */
dequeiter_methods, /* tp_methods */
0,
};
/*********************** Deque Reverse Iterator **************************/
static PyTypeObject dequereviter_type;
static PyObject *
deque_reviter(dequeobject *deque)
{
dequeiterobject *it;
it = PyObject_GC_New(dequeiterobject, &dequereviter_type);
if (it == NULL)
return NULL;
it->b = deque->rightblock;
it->index = deque->rightindex;
Py_INCREF(deque);
it->deque = deque;
it->state = deque->state;
it->counter = deque->len;
PyObject_GC_Track(it);
return (PyObject *)it;
}
static PyObject *
dequereviter_next(dequeiterobject *it)
{
PyObject *item;
if (it->counter == 0)
return NULL;
if (it->deque->state != it->state) {
it->counter = 0;
PyErr_SetString(PyExc_RuntimeError,
"deque mutated during iteration");
return NULL;
}
assert (!(it->b == it->deque->leftblock &&
it->index < it->deque->leftindex));
item = it->b->data[it->index];
it->index--;
it->counter--;
if (it->index == -1 && it->counter > 0) {
assert (it->b->leftlink != NULL);
it->b = it->b->leftlink;
it->index = BLOCKLEN - 1;
}
Py_INCREF(item);
return item;
}
static PyTypeObject dequereviter_type = {
PyVarObject_HEAD_INIT(NULL, 0)
"deque_reverse_iterator", /* tp_name */
sizeof(dequeiterobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)dequeiter_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
0, /* tp_doc */
(traverseproc)dequeiter_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)dequereviter_next, /* tp_iternext */
dequeiter_methods, /* tp_methods */
0,
};
/* defaultdict type *********************************************************/
typedef struct {
PyDictObject dict;
PyObject *default_factory;
} defdictobject;
static PyTypeObject defdict_type; /* Forward */
PyDoc_STRVAR(defdict_missing_doc,
"__missing__(key) # Called by __getitem__ for missing key; pseudo-code:\n\
if self.default_factory is None: raise KeyError((key,))\n\
self[key] = value = self.default_factory()\n\
return value\n\
");
static PyObject *
defdict_missing(defdictobject *dd, PyObject *key)
{
PyObject *factory = dd->default_factory;
PyObject *value;
if (factory == NULL || factory == Py_None) {
/* XXX Call dict.__missing__(key) */
PyObject *tup;
tup = PyTuple_Pack(1, key);
if (!tup) return NULL;
PyErr_SetObject(PyExc_KeyError, tup);
Py_DECREF(tup);
return NULL;
}
value = PyEval_CallObject(factory, NULL);
if (value == NULL)
return value;
if (PyObject_SetItem((PyObject *)dd, key, value) < 0) {
Py_DECREF(value);
return NULL;
}
return value;
}
PyDoc_STRVAR(defdict_copy_doc, "D.copy() -> a shallow copy of D.");
static PyObject *
defdict_copy(defdictobject *dd)
{
/* This calls the object's class. That only works for subclasses
whose class constructor has the same signature. Subclasses that
define a different constructor signature must override copy().
*/
if (dd->default_factory == NULL)
return PyObject_CallFunctionObjArgs((PyObject*)Py_TYPE(dd), Py_None, dd, NULL);
return PyObject_CallFunctionObjArgs((PyObject*)Py_TYPE(dd),
dd->default_factory, dd, NULL);
}
static PyObject *
defdict_reduce(defdictobject *dd)
{
/* __reduce__ must return a 5-tuple as follows:
- factory function
- tuple of args for the factory function
- additional state (here None)
- sequence iterator (here None)
- dictionary iterator (yielding successive (key, value) pairs
This API is used by pickle.py and copy.py.
For this to be useful with pickle.py, the default_factory
must be picklable; e.g., None, a built-in, or a global
function in a module or package.
Both shallow and deep copying are supported, but for deep
copying, the default_factory must be deep-copyable; e.g. None,
or a built-in (functions are not copyable at this time).
This only works for subclasses as long as their constructor
signature is compatible; the first argument must be the
optional default_factory, defaulting to None.
*/
PyObject *args;
PyObject *items;
PyObject *iter;
PyObject *result;
if (dd->default_factory == NULL || dd->default_factory == Py_None)
args = PyTuple_New(0);
else
args = PyTuple_Pack(1, dd->default_factory);
if (args == NULL)
return NULL;
items = PyObject_CallMethod((PyObject *)dd, "items", "()");
if (items == NULL) {
Py_DECREF(args);
return NULL;
}
iter = PyObject_GetIter(items);
if (iter == NULL) {
Py_DECREF(items);
Py_DECREF(args);
return NULL;
}
result = PyTuple_Pack(5, Py_TYPE(dd), args,
Py_None, Py_None, iter);
Py_DECREF(iter);
Py_DECREF(items);
Py_DECREF(args);
return result;
}
static PyMethodDef defdict_methods[] = {
{"__missing__", (PyCFunction)defdict_missing, METH_O,
defdict_missing_doc},
{"copy", (PyCFunction)defdict_copy, METH_NOARGS,
defdict_copy_doc},
{"__copy__", (PyCFunction)defdict_copy, METH_NOARGS,
defdict_copy_doc},
{"__reduce__", (PyCFunction)defdict_reduce, METH_NOARGS,
reduce_doc},
{NULL}
};
static PyMemberDef defdict_members[] = {
{"default_factory", T_OBJECT,
offsetof(defdictobject, default_factory), 0,
PyDoc_STR("Factory for default value called by __missing__().")},
{NULL}
};
static void
defdict_dealloc(defdictobject *dd)
{
Py_CLEAR(dd->default_factory);
PyDict_Type.tp_dealloc((PyObject *)dd);
}
static PyObject *
defdict_repr(defdictobject *dd)
{
PyObject *baserepr;
PyObject *defrepr;
PyObject *result;
baserepr = PyDict_Type.tp_repr((PyObject *)dd);
if (baserepr == NULL)
return NULL;
if (dd->default_factory == NULL)
defrepr = PyUnicode_FromString("None");
else
{
int status = Py_ReprEnter(dd->default_factory);
if (status != 0) {
if (status < 0)
return NULL;
defrepr = PyUnicode_FromString("...");
}
else
defrepr = PyObject_Repr(dd->default_factory);
Py_ReprLeave(dd->default_factory);
}
if (defrepr == NULL) {
Py_DECREF(baserepr);
return NULL;
}
result = PyUnicode_FromFormat("defaultdict(%U, %U)",
defrepr, baserepr);
Py_DECREF(defrepr);
Py_DECREF(baserepr);
return result;
}
static int
defdict_traverse(PyObject *self, visitproc visit, void *arg)
{
Py_VISIT(((defdictobject *)self)->default_factory);
return PyDict_Type.tp_traverse(self, visit, arg);
}
static int
defdict_tp_clear(defdictobject *dd)
{
Py_CLEAR(dd->default_factory);
return PyDict_Type.tp_clear((PyObject *)dd);
}
static int
defdict_init(PyObject *self, PyObject *args, PyObject *kwds)
{
defdictobject *dd = (defdictobject *)self;
PyObject *olddefault = dd->default_factory;
PyObject *newdefault = NULL;
PyObject *newargs;
int result;
if (args == NULL || !PyTuple_Check(args))
newargs = PyTuple_New(0);
else {
Py_ssize_t n = PyTuple_GET_SIZE(args);
if (n > 0) {
newdefault = PyTuple_GET_ITEM(args, 0);
if (!PyCallable_Check(newdefault) && newdefault != Py_None) {
PyErr_SetString(PyExc_TypeError,
"first argument must be callable");
return -1;
}
}
newargs = PySequence_GetSlice(args, 1, n);
}
if (newargs == NULL)
return -1;
Py_XINCREF(newdefault);
dd->default_factory = newdefault;
result = PyDict_Type.tp_init(self, newargs, kwds);
Py_DECREF(newargs);
Py_XDECREF(olddefault);
return result;
}
PyDoc_STRVAR(defdict_doc,
"defaultdict(default_factory) --> dict with default factory\n\
\n\
The default factory is called without arguments to produce\n\
a new value when a key is not present, in __getitem__ only.\n\
A defaultdict compares equal to a dict with the same items.\n\
");
/* See comment in xxsubtype.c */
#define DEFERRED_ADDRESS(ADDR) 0
static PyTypeObject defdict_type = {
PyVarObject_HEAD_INIT(DEFERRED_ADDRESS(&PyType_Type), 0)
"collections.defaultdict", /* tp_name */
sizeof(defdictobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)defdict_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
(reprfunc)defdict_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
/* tp_flags */
defdict_doc, /* tp_doc */
defdict_traverse, /* tp_traverse */
(inquiry)defdict_tp_clear, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset*/
0, /* tp_iter */
0, /* tp_iternext */
defdict_methods, /* tp_methods */
defdict_members, /* tp_members */
0, /* tp_getset */
DEFERRED_ADDRESS(&PyDict_Type), /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
defdict_init, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
0, /* tp_new */
PyObject_GC_Del, /* tp_free */
};
/* helper function for Counter *********************************************/
PyDoc_STRVAR(_count_elements_doc,
"_count_elements(mapping, iterable) -> None\n\
\n\
Count elements in the iterable, updating the mappping");
static PyObject *
_count_elements(PyObject *self, PyObject *args)
{
PyObject *it, *iterable, *mapping, *oldval;
PyObject *newval = NULL;
PyObject *key = NULL;
PyObject *one = NULL;
if (!PyArg_UnpackTuple(args, "_count_elements", 2, 2, &mapping, &iterable))
return NULL;
it = PyObject_GetIter(iterable);
if (it == NULL)
return NULL;
one = PyLong_FromLong(1);
if (one == NULL) {
Py_DECREF(it);
return NULL;
}
if (PyDict_CheckExact(mapping)) {
while (1) {
key = PyIter_Next(it);
if (key == NULL)
break;
oldval = PyDict_GetItem(mapping, key);
if (oldval == NULL) {
if (PyDict_SetItem(mapping, key, one) == -1)
break;
} else {
newval = PyNumber_Add(oldval, one);
if (newval == NULL)
break;
if (PyDict_SetItem(mapping, key, newval) == -1)
break;
Py_CLEAR(newval);
}
Py_DECREF(key);
}
} else {
while (1) {
key = PyIter_Next(it);
if (key == NULL)
break;
oldval = PyObject_GetItem(mapping, key);
if (oldval == NULL) {
if (!PyErr_Occurred() || !PyErr_ExceptionMatches(PyExc_KeyError))
break;
PyErr_Clear();
Py_INCREF(one);
newval = one;
} else {
newval = PyNumber_Add(oldval, one);
Py_DECREF(oldval);
if (newval == NULL)
break;
}
if (PyObject_SetItem(mapping, key, newval) == -1)
break;
Py_CLEAR(newval);
Py_DECREF(key);
}
}
Py_DECREF(it);
Py_XDECREF(key);
Py_XDECREF(newval);
Py_DECREF(one);
if (PyErr_Occurred())
return NULL;
Py_RETURN_NONE;
}
/* module level code ********************************************************/
PyDoc_STRVAR(module_doc,
"High performance data structures.\n\
- deque: ordered collection accessible from endpoints only\n\
- defaultdict: dict subclass with a default value factory\n\
");
static struct PyMethodDef module_functions[] = {
{"_count_elements", _count_elements, METH_VARARGS, _count_elements_doc},
{NULL, NULL} /* sentinel */
};
static struct PyModuleDef _collectionsmodule = {
PyModuleDef_HEAD_INIT,
"_collections",
module_doc,
-1,
module_functions,
NULL,
NULL,
NULL,
NULL
};
PyMODINIT_FUNC
PyInit__collections(void)
{
PyObject *m;
m = PyModule_Create(&_collectionsmodule);
if (m == NULL)
return NULL;
if (PyType_Ready(&deque_type) < 0)
return NULL;
Py_INCREF(&deque_type);
PyModule_AddObject(m, "deque", (PyObject *)&deque_type);
defdict_type.tp_base = &PyDict_Type;
if (PyType_Ready(&defdict_type) < 0)
return NULL;
Py_INCREF(&defdict_type);
PyModule_AddObject(m, "defaultdict", (PyObject *)&defdict_type);
if (PyType_Ready(&dequeiter_type) < 0)
return NULL;
if (PyType_Ready(&dequereviter_type) < 0)
return NULL;
return m;
}
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