_collectionsmodule.c 48.6 KB
Newer Older
1
#include "Python.h"
2
#include "structmember.h"
3 4 5 6 7 8 9

/* 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.
*/

10 11 12
/* 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
13
 * length of a cache line.
14 15
 */

Raymond Hettinger's avatar
Raymond Hettinger committed
16
#define BLOCKLEN 62
17
#define CENTER ((BLOCKLEN - 1) / 2)
18

19 20 21 22 23
/* 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
24
 * indices, these indices are inclusive on both ends.  By being inclusive
25
 * on both ends, algorithms for left and right operations become
26
 * symmetrical which simplifies the design.
27
 *
28 29 30 31 32
 * 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.
33 34
 * Their exact relationship is:
 *     (d.leftindex + d.len - 1) % BLOCKLEN == d.rightindex.
35 36 37 38 39
 *
 * 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.
 *
40
 * Whenever d.leftblock == d.rightblock,
41
 *     d.leftindex + d.len - 1 == d.rightindex.
42
 *
43
 * However, when d.leftblock != d.rightblock, d.leftindex and d.rightindex
44
 * become indices into distinct blocks and either may be larger than the
45
 * other.
46 47
 */

48
typedef struct BLOCK {
49 50 51
    struct BLOCK *leftlink;
    struct BLOCK *rightlink;
    PyObject *data[BLOCKLEN];
52 53
} block;

54
#define MAXFREEBLOCKS 10
55
static Py_ssize_t numfreeblocks = 0;
56 57
static block *freeblocks[MAXFREEBLOCKS];

Tim Peters's avatar
Tim Peters committed
58
static block *
59
newblock(block *leftlink, block *rightlink, Py_ssize_t len) {
60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85
    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;
86 87
}

88
static void
89 90
freeblock(block *b)
{
91 92 93 94 95 96
    if (numfreeblocks < MAXFREEBLOCKS) {
        freeblocks[numfreeblocks] = b;
        numfreeblocks++;
    } else {
        PyMem_Free(b);
    }
97 98
}

99
typedef struct {
100 101 102 103 104 105 106 107 108
    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 */
109 110
} dequeobject;

111 112
/* The deque's size limit is d.maxlen.  The limit can be zero or positive.
 * If there is no limit, then d.maxlen == -1.
113
 *
114 115 116 117 118 119
 * 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().
 */

120 121 122 123 124
#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);                                      \
125 126
    }

127
static PyTypeObject deque_type;
128

129 130 131
static PyObject *
deque_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
    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;
157 158 159 160 161
}

static PyObject *
deque_pop(dequeobject *deque, PyObject *unused)
{
162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190
    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;
191 192 193 194 195 196 197
}

PyDoc_STRVAR(pop_doc, "Remove and return the rightmost element.");

static PyObject *
deque_popleft(dequeobject *deque, PyObject *unused)
{
198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228
    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;
229 230 231 232
}

PyDoc_STRVAR(popleft_doc, "Remove and return the leftmost element.");

233 234 235
static PyObject *
deque_append(dequeobject *deque, PyObject *item)
{
236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251
    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;
252 253 254 255 256 257 258
}

PyDoc_STRVAR(append_doc, "Add an element to the right side of the deque.");

static PyObject *
deque_appendleft(dequeobject *deque, PyObject *item)
{
259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274
    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;
275 276 277 278
}

PyDoc_STRVAR(appendleft_doc, "Add an element to the left side of the deque.");

279

280
/* Run an iterator to exhaustion.  Shortcut for
281 282 283 284
   the extend/extendleft methods when maxlen == 0. */
static PyObject*
consume_iterator(PyObject *it)
{
285 286 287 288 289 290 291 292 293
    PyObject *item;

    while ((item = PyIter_Next(it)) != NULL) {
        Py_DECREF(item);
    }
    Py_DECREF(it);
    if (PyErr_Occurred())
        return NULL;
    Py_RETURN_NONE;
294 295
}

296 297 298
static PyObject *
deque_extend(dequeobject *deque, PyObject *iterable)
{
299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
    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;
343 344
}

345
PyDoc_STRVAR(extend_doc,
346 347 348 349 350
"Extend the right side of the deque with elements from the iterable");

static PyObject *
deque_extendleft(dequeobject *deque, PyObject *iterable)
{
351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394
    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;
395 396
}

397
PyDoc_STRVAR(extendleft_doc,
398 399
"Extend the left side of the deque with elements from the iterable");

400 401 402
static PyObject *
deque_inplace_concat(dequeobject *deque, PyObject *other)
{
403 404 405 406 407 408 409 410
    PyObject *result;

    result = deque_extend(deque, other);
    if (result == NULL)
        return result;
    Py_DECREF(result);
    Py_INCREF(deque);
    return (PyObject *)deque;
411 412
}

413
static int
Martin v. Löwis's avatar
Martin v. Löwis committed
414
_deque_rotate(dequeobject *deque, Py_ssize_t n)
415
{
416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447
    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;
448 449 450 451 452
}

static PyObject *
deque_rotate(dequeobject *deque, PyObject *args)
{
453
    Py_ssize_t n=1;
454

455 456 457 458 459
    if (!PyArg_ParseTuple(args, "|n:rotate", &n))
        return NULL;
    if (_deque_rotate(deque, n) == 0)
        Py_RETURN_NONE;
    return NULL;
460 461
}

462
PyDoc_STRVAR(rotate_doc,
463
"Rotate the deque n steps to the right (default n=1).  If n is negative, rotates left.");
464

465 466 467
static PyObject *
deque_reverse(dequeobject *deque, PyObject *unused)
{
468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501
    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) {
            assert (leftblock->rightlink != NULL);
            leftblock = leftblock->rightlink;
            leftindex = 0;
        }

        /* Step backwards with the right block/index pair */
        rightindex--;
        if (rightindex == -1) {
            assert (rightblock->leftlink != NULL);
            rightblock = rightblock->leftlink;
            rightindex = BLOCKLEN - 1;
        }
    }
    Py_RETURN_NONE;
502 503 504 505 506
}

PyDoc_STRVAR(reverse_doc,
"D.reverse() -- reverse *IN PLACE*");

507 508 509
static PyObject *
deque_count(dequeobject *deque, PyObject *v)
{
510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541
    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) {
            assert (leftblock->rightlink != NULL);
            leftblock = leftblock->rightlink;
            leftindex = 0;
        }
    }
    return PyLong_FromSsize_t(count);
542 543 544 545 546
}

PyDoc_STRVAR(count_doc,
"D.count(value) -> integer -- return number of occurrences of value");

Martin v. Löwis's avatar
Martin v. Löwis committed
547
static Py_ssize_t
548 549
deque_len(dequeobject *deque)
{
550
    return deque->len;
551 552
}

553 554 555
static PyObject *
deque_remove(dequeobject *deque, PyObject *value)
{
556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582
    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;
583 584 585 586 587
}

PyDoc_STRVAR(remove_doc,
"D.remove(value) -- remove first occurrence of value.");

588 589 590
static int
deque_clear(dequeobject *deque)
{
591 592 593 594 595 596 597 598 599 600 601
    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;
602 603
}

604
static PyObject *
605
deque_item(dequeobject *deque, Py_ssize_t i)
606
{
607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640
    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;
641 642
}

643 644
/* delitem() implemented in terms of rotate for simplicity and reasonable
   performance near the end points.  If for some reason this method becomes
645
   popular, it is not hard to re-implement this using direct data movement
646 647 648 649
   (similar to code in list slice assignment) and achieve a two or threefold
   performance boost.
*/

650
static int
Martin v. Löwis's avatar
Martin v. Löwis committed
651
deque_del_item(dequeobject *deque, Py_ssize_t i)
652
{
653
    PyObject *item;
654

655 656 657
    assert (i >= 0 && i < deque->len);
    if (_deque_rotate(deque, -i) == -1)
        return -1;
658

659 660 661
    item = deque_popleft(deque, NULL);
    assert (item != NULL);
    Py_DECREF(item);
662

663
    return _deque_rotate(deque, i);
664 665
}

666
static int
Martin v. Löwis's avatar
Martin v. Löwis committed
667
deque_ass_item(dequeobject *deque, Py_ssize_t i, PyObject *v)
668
{
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698
    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;
699 700
}

701 702 703
static PyObject *
deque_clearmethod(dequeobject *deque)
{
704
    int rv;
705

706 707 708
    rv = deque_clear(deque);
    assert (rv != -1);
    Py_RETURN_NONE;
709 710 711 712 713 714 715
}

PyDoc_STRVAR(clear_doc, "Remove all elements from the deque.");

static void
deque_dealloc(dequeobject *deque)
{
716 717 718 719 720 721 722 723 724 725 726
    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);
727 728 729
}

static int
730
deque_traverse(dequeobject *deque, visitproc visit, void *arg)
731
{
732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
    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;
749 750 751 752 753
}

static PyObject *
deque_copy(PyObject *deque)
{
754 755 756 757 758
    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);
759 760 761 762 763 764 765
}

PyDoc_STRVAR(copy_doc, "Return a shallow copy of a deque.");

static PyObject *
deque_reduce(dequeobject *deque)
{
766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789
    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;
790 791 792 793 794 795 796
}

PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");

static PyObject *
deque_repr(PyObject *deque)
{
797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820
    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;
821 822
}

823 824 825
static PyObject *
deque_richcompare(PyObject *v, PyObject *w, int op)
{
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890
    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_INCREF(Py_NotImplemented);
        return Py_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 */
    }
891

892
done:
893 894 895 896 897 898 899
    Py_XDECREF(it1);
    Py_XDECREF(it2);
    if (cmp == 1)
        Py_RETURN_TRUE;
    if (cmp == 0)
        Py_RETURN_FALSE;
    return NULL;
900 901
}

902
static int
903
deque_init(dequeobject *deque, PyObject *args, PyObject *kwdargs)
904
{
905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929
    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;
930 931
}

932 933 934
static PyObject *
deque_get_maxlen(dequeobject *deque)
{
935 936 937
    if (deque->maxlen == -1)
        Py_RETURN_NONE;
    return PyLong_FromSsize_t(deque->maxlen);
938 939 940
}

static PyGetSetDef deque_getset[] = {
941 942 943
    {"maxlen", (getter)deque_get_maxlen, (setter)NULL,
     "maximum size of a deque or None if unbounded"},
    {0}
944 945
};

946
static PySequenceMethods deque_as_sequence = {
947 948 949 950 951 952 953 954 955 956
    (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 */
957

958 959 960 961 962
};

/* deque object ********************************************************/

static PyObject *deque_iter(dequeobject *deque);
963
static PyObject *deque_reviter(dequeobject *deque);
964
PyDoc_STRVAR(reversed_doc,
965
    "D.__reversed__() -- return a reverse iterator over the deque");
966 967

static PyMethodDef deque_methods[] = {
968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996
    {"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 */
997 998 999
};

PyDoc_STRVAR(deque_doc,
1000
"deque(iterable[, maxlen]) --> deque object\n\
1001 1002 1003
\n\
Build an ordered collection accessible from endpoints only.");

1004
static PyTypeObject deque_type = {
1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
    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 */
1019
    PyObject_HashNotImplemented,        /* tp_hash */
1020 1021 1022 1023 1024 1025
    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,
1026
                                        /* tp_flags */
1027 1028 1029 1030
    deque_doc,                          /* tp_doc */
    (traverseproc)deque_traverse,       /* tp_traverse */
    (inquiry)deque_clear,               /* tp_clear */
    (richcmpfunc)deque_richcompare,     /* tp_richcompare */
1031
    offsetof(dequeobject, weakreflist), /* tp_weaklistoffset*/
1032 1033 1034 1035
    (getiterfunc)deque_iter,            /* tp_iter */
    0,                                  /* tp_iternext */
    deque_methods,                      /* tp_methods */
    0,                                  /* tp_members */
1036
    deque_getset,                       /* tp_getset */
1037 1038 1039 1040 1041 1042 1043 1044 1045
    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 */
1046 1047 1048 1049 1050
};

/*********************** Deque Iterator **************************/

typedef struct {
1051 1052 1053 1054 1055 1056
    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 */
1057 1058
} dequeiterobject;

1059
static PyTypeObject dequeiter_type;
1060 1061 1062 1063

static PyObject *
deque_iter(dequeobject *deque)
{
1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076
    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;
1077 1078
}

1079 1080 1081
static int
dequeiter_traverse(dequeiterobject *dio, visitproc visit, void *arg)
{
1082 1083
    Py_VISIT(dio->deque);
    return 0;
1084 1085
}

1086 1087 1088
static void
dequeiter_dealloc(dequeiterobject *dio)
{
1089 1090
    Py_XDECREF(dio->deque);
    PyObject_GC_Del(dio);
1091 1092 1093 1094 1095
}

static PyObject *
dequeiter_next(dequeiterobject *it)
{
1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
    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;
1119 1120
}

1121
static PyObject *
1122 1123
dequeiter_len(dequeiterobject *it)
{
1124
    return PyLong_FromSsize_t(it->counter);
1125 1126
}

1127
PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
1128 1129

static PyMethodDef dequeiter_methods[] = {
1130 1131
    {"__length_hint__", (PyCFunction)dequeiter_len, METH_NOARGS, length_hint_doc},
    {NULL,              NULL}           /* sentinel */
1132 1133
};

1134
static PyTypeObject dequeiter_type = {
1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
    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,
1165 1166
};

1167 1168
/*********************** Deque Reverse Iterator **************************/

1169
static PyTypeObject dequereviter_type;
1170 1171 1172 1173

static PyObject *
deque_reviter(dequeobject *deque)
{
1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
    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;
1187 1188 1189 1190 1191
}

static PyObject *
dequereviter_next(dequeiterobject *it)
{
1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214
    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;
1215 1216
}

1217
static PyTypeObject dequereviter_type = {
1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247
    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,
1248 1249
};

Guido van Rossum's avatar
Guido van Rossum committed
1250 1251 1252
/* defaultdict type *********************************************************/

typedef struct {
1253 1254
    PyDictObject dict;
    PyObject *default_factory;
Guido van Rossum's avatar
Guido van Rossum committed
1255 1256 1257 1258 1259 1260
} defdictobject;

static PyTypeObject defdict_type; /* Forward */

PyDoc_STRVAR(defdict_missing_doc,
"__missing__(key) # Called by __getitem__ for missing key; pseudo-code:\n\
1261
  if self.default_factory is None: raise KeyError((key,))\n\
Guido van Rossum's avatar
Guido van Rossum committed
1262 1263 1264 1265 1266 1267 1268
  self[key] = value = self.default_factory()\n\
  return value\n\
");

static PyObject *
defdict_missing(defdictobject *dd, PyObject *key)
{
1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
    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;
Guido van Rossum's avatar
Guido van Rossum committed
1288 1289 1290 1291 1292 1293 1294
}

PyDoc_STRVAR(defdict_copy_doc, "D.copy() -> a shallow copy of D.");

static PyObject *
defdict_copy(defdictobject *dd)
{
1295 1296 1297 1298 1299 1300 1301 1302 1303
    /* 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);
Guido van Rossum's avatar
Guido van Rossum committed
1304 1305 1306 1307 1308
}

static PyObject *
defdict_reduce(defdictobject *dd)
{
1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357
    /* __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;
Guido van Rossum's avatar
Guido van Rossum committed
1358 1359 1360
}

static PyMethodDef defdict_methods[] = {
1361 1362 1363 1364 1365 1366 1367 1368 1369
    {"__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}
Guido van Rossum's avatar
Guido van Rossum committed
1370 1371 1372
};

static PyMemberDef defdict_members[] = {
1373 1374 1375 1376
    {"default_factory", T_OBJECT,
     offsetof(defdictobject, default_factory), 0,
     PyDoc_STR("Factory for default value called by __missing__().")},
    {NULL}
Guido van Rossum's avatar
Guido van Rossum committed
1377 1378 1379 1380 1381
};

static void
defdict_dealloc(defdictobject *dd)
{
1382 1383
    Py_CLEAR(dd->default_factory);
    PyDict_Type.tp_dealloc((PyObject *)dd);
Guido van Rossum's avatar
Guido van Rossum committed
1384 1385 1386 1387 1388
}

static PyObject *
defdict_repr(defdictobject *dd)
{
1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417
    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;
Guido van Rossum's avatar
Guido van Rossum committed
1418 1419 1420 1421 1422
}

static int
defdict_traverse(PyObject *self, visitproc visit, void *arg)
{
1423 1424
    Py_VISIT(((defdictobject *)self)->default_factory);
    return PyDict_Type.tp_traverse(self, visit, arg);
Guido van Rossum's avatar
Guido van Rossum committed
1425 1426 1427 1428 1429
}

static int
defdict_tp_clear(defdictobject *dd)
{
1430 1431
    Py_CLEAR(dd->default_factory);
    return PyDict_Type.tp_clear((PyObject *)dd);
Guido van Rossum's avatar
Guido van Rossum committed
1432 1433 1434 1435 1436
}

static int
defdict_init(PyObject *self, PyObject *args, PyObject *kwds)
{
1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463
    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;
Guido van Rossum's avatar
Guido van Rossum committed
1464 1465 1466 1467 1468 1469 1470 1471 1472 1473
}

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\
");

1474 1475 1476
/* See comment in xxsubtype.c */
#define DEFERRED_ADDRESS(ADDR) 0

Guido van Rossum's avatar
Guido van Rossum committed
1477
static PyTypeObject defdict_type = {
1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
    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 */
Guido van Rossum's avatar
Guido van Rossum committed
1519 1520
};

1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582
/* 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;

    if (!PyDict_Check(mapping)) {
        PyErr_SetString(PyExc_TypeError,
            "Expected mapping argument to be a dictionary");
        return NULL;
    }

    it = PyObject_GetIter(iterable);
    if (it == NULL)
        return NULL;
    one = PyLong_FromLong(1);
    if (one == NULL) {
        Py_DECREF(it);
        return NULL;
    }
    while (1) {
        key = PyIter_Next(it);
        if (key == NULL) {
            if (PyErr_Occurred() && PyErr_ExceptionMatches(PyExc_StopIteration))
                PyErr_Clear();
            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);
    }
    Py_DECREF(it);
    Py_XDECREF(key);
    Py_XDECREF(newval);
    Py_DECREF(one);
    if (PyErr_Occurred())
        return NULL;
    Py_RETURN_NONE;
}

1583 1584 1585
/* module level code ********************************************************/

PyDoc_STRVAR(module_doc,
Guido van Rossum's avatar
Guido van Rossum committed
1586 1587 1588
"High performance data structures.\n\
- deque:        ordered collection accessible from endpoints only\n\
- defaultdict:  dict subclass with a default value factory\n\
1589 1590
");

1591 1592 1593 1594
static struct PyMethodDef module_functions[] = {
    {"_count_elements", _count_elements,    METH_VARARGS,   _count_elements_doc},
    {NULL,       NULL}          /* sentinel */
};
1595 1596

static struct PyModuleDef _collectionsmodule = {
1597 1598 1599 1600
    PyModuleDef_HEAD_INIT,
    "_collections",
    module_doc,
    -1,
1601
    module_functions,
1602 1603 1604 1605
    NULL,
    NULL,
    NULL,
    NULL
1606 1607
};

1608
PyMODINIT_FUNC
1609
PyInit__collections(void)
1610
{
1611
    PyObject *m;
1612

1613 1614 1615
    m = PyModule_Create(&_collectionsmodule);
    if (m == NULL)
        return NULL;
1616

1617 1618 1619 1620
    if (PyType_Ready(&deque_type) < 0)
        return NULL;
    Py_INCREF(&deque_type);
    PyModule_AddObject(m, "deque", (PyObject *)&deque_type);
1621

1622 1623 1624 1625 1626
    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);
Guido van Rossum's avatar
Guido van Rossum committed
1627

1628 1629
    if (PyType_Ready(&dequeiter_type) < 0)
        return NULL;
1630

1631 1632
    if (PyType_Ready(&dequereviter_type) < 0)
        return NULL;
1633

1634
    return m;
1635
}