#include "Python.h"

#include "accu.h"

#include "clinic/tupleobject.c.h"

#ifndef PyTuple_MAXSAVESIZE

#define PyTuple_MAXSAVESIZE 20 /* Largest tuple to save on free list */

#ifndef PyTuple_MAXFREELIST

#define PyTuple_MAXFREELIST 2000 /* Maximum number of tuples of each size to save */

#if PyTuple_MAXSAVESIZE > 0

static PyTupleObject *free_list[PyTuple_MAXSAVESIZE];

static int numfree[PyTuple_MAXSAVESIZE];

#ifdef COUNT_ALLOCS

Py_ssize_t fast_tuple_allocs;

Py_ssize_t tuple_zero_allocs;

#ifdef SHOW_TRACK_COUNT

static Py_ssize_t count_untracked = 0;

static Py_ssize_t count_tracked = 0;

static void

show_track(void)

{

PyObject *xoptions, *value;

_Py_IDENTIFIER(showalloccount);

xoptions = PySys_GetXOptions();

if (xoptions == NULL)

return;

value = _PyDict_GetItemId(xoptions, &PyId_showalloccount);

if (value != Py_True)

return;

fprintf(stderr, "Tuples created: %" PY_FORMAT_SIZE_T "d\n",

count_tracked + count_untracked);

fprintf(stderr, "Tuples tracked by the GC: %" PY_FORMAT_SIZE_T

"d\n", count_tracked);

fprintf(stderr, "%.2f%% tuple tracking rate\n\n",

(100.0*count_tracked/(count_untracked+count_tracked)));

}

_PyTuple_DebugMallocStats(FILE *out)

{

#if PyTuple_MAXSAVESIZE > 0

int i;

char buf[128];

for (i = 1; i < PyTuple_MAXSAVESIZE; i++) {

PyOS_snprintf(buf, sizeof(buf),

"free %d-sized PyTupleObject", i);

_PyDebugAllocatorStats(out,

buf,

numfree[i], _PyObject_VAR_SIZE(&PyTuple_Type, i));

}

}

PyObject *

PyTuple_New(Py_ssize_t size)

{

PyTupleObject *op;

Py_ssize_t i;

if (size < 0) {

PyErr_BadInternalCall();

return NULL;

}

#if PyTuple_MAXSAVESIZE > 0

if (size == 0 && free_list[0]) {

op = free_list[0];

Py_INCREF(op);

#ifdef COUNT_ALLOCS

tuple_zero_allocs++;

return (PyObject *) op;

}

if (size < PyTuple_MAXSAVESIZE && (op = free_list[size]) != NULL) {

free_list[size] = (PyTupleObject *) op->ob_item[0];

numfree[size]--;

#ifdef COUNT_ALLOCS

fast_tuple_allocs++;

/* Inline PyObject_InitVar */

#ifdef Py_TRACE_REFS

Py_SIZE(op) = size;

Py_TYPE(op) = &PyTuple_Type;

_Py_NewReference((PyObject *)op);

}

else

{

/* Check for overflow */

if ((size_t)size > ((size_t)PY_SSIZE_T_MAX - sizeof(PyTupleObject) -

sizeof(PyObject *)) / sizeof(PyObject *)) {

return PyErr_NoMemory();

}

op = PyObject_GC_NewVar(PyTupleObject, &PyTuple_Type, size);

if (op == NULL)

return NULL;

}

for (i=0; i < size; i++)

op->ob_item[i] = NULL;

#if PyTuple_MAXSAVESIZE > 0

if (size == 0) {

free_list[0] = op;

++numfree[0];

Py_INCREF(op); /* extra INCREF so that this is never freed */

}

#ifdef SHOW_TRACK_COUNT

count_tracked++;

_PyObject_GC_TRACK(op);

return (PyObject *) op;

}

PyTuple_Size(PyObject *op)

{

if (!PyTuple_Check(op)) {

PyErr_BadInternalCall();

return -1;

}

else

return Py_SIZE(op);

}

PyObject *

PyTuple_GetItem(PyObject *op, Py_ssize_t i)

{

if (!PyTuple_Check(op)) {

PyErr_BadInternalCall();

return NULL;

}

if (i < 0 || i >= Py_SIZE(op)) {

PyErr_SetString(PyExc_IndexError, "tuple index out of range");

return NULL;

}

return ((PyTupleObject *)op) -> ob_item[i];

}

PyTuple_SetItem(PyObject *op, Py_ssize_t i, PyObject *newitem)

{

PyObject **p;

if (!PyTuple_Check(op) || op->ob_refcnt != 1) {

Py_XDECREF(newitem);

PyErr_BadInternalCall();

return -1;

}

if (i < 0 || i >= Py_SIZE(op)) {

Py_XDECREF(newitem);

PyErr_SetString(PyExc_IndexError,

"tuple assignment index out of range");

return -1;

}

p = ((PyTupleObject *)op) -> ob_item + i;

Py_XSETREF(*p, newitem);

return 0;

}

_PyTuple_MaybeUntrack(PyObject *op)

{

PyTupleObject *t;

Py_ssize_t i, n;

if (!PyTuple_CheckExact(op) || !_PyObject_GC_IS_TRACKED(op))

return;

t = (PyTupleObject *) op;

n = Py_SIZE(t);

for (i = 0; i < n; i++) {

PyObject *elt = PyTuple_GET_ITEM(t, i);

/* Tuple with NULL elements aren't

if (!elt ||

_PyObject_GC_MAY_BE_TRACKED(elt))

return;

}

#ifdef SHOW_TRACK_COUNT

count_tracked--;

count_untracked++;

_PyObject_GC_UNTRACK(op);

}

PyObject *

PyTuple_Pack(Py_ssize_t n, ...)

{

Py_ssize_t i;

PyObject *o;

PyObject *result;

PyObject **items;

va_list vargs;

va_start(vargs, n);

result = PyTuple_New(n);

if (result == NULL) {

va_end(vargs);

return NULL;

}

items = ((PyTupleObject *)result)->ob_item;

for (i = 0; i < n; i++) {

o = va_arg(vargs, PyObject *);

Py_INCREF(o);

items[i] = o;

}

va_end(vargs);

return result;

}

static void

tupledealloc(PyTupleObject *op)

{

Py_ssize_t i;

Py_ssize_t len = Py_SIZE(op);

PyObject_GC_UnTrack(op);

Py_TRASHCAN_SAFE_BEGIN(op)

if (len > 0) {

i = len;

while (--i >= 0)

Py_XDECREF(op->ob_item[i]);

#if PyTuple_MAXSAVESIZE > 0

if (len < PyTuple_MAXSAVESIZE &&

numfree[len] < PyTuple_MAXFREELIST &&

Py_TYPE(op) == &PyTuple_Type)

{

op->ob_item[0] = (PyObject *) free_list[len];

numfree[len]++;

free_list[len] = op;

goto done; /* return */

}

}

Py_TYPE(op)->tp_free((PyObject *)op);

done:

Py_TRASHCAN_SAFE_END(op)

}

static PyObject *

tuplerepr(PyTupleObject *v)

{

Py_ssize_t i, n;

_PyUnicodeWriter writer;

n = Py_SIZE(v);

if (n == 0)

return PyUnicode_FromString("()");

/* While not mutable, it is still possible to end up with a cycle in a

i = Py_ReprEnter((PyObject *)v);

if (i != 0) {

return i > 0 ? PyUnicode_FromString("(...)") : NULL;

}

_PyUnicodeWriter_Init(&writer);

writer.overallocate = 1;

if (Py_SIZE(v) > 1) {

/* "(" + "1" + ", 2" * (len - 1) + ")" */

writer.min_length = 1 + 1 + (2 + 1) * (Py_SIZE(v) - 1) + 1;

}

else {

/* "(1,)" */

writer.min_length = 4;

}

if (_PyUnicodeWriter_WriteChar(&writer, '(') < 0)

goto error;

/* Do repr() on each element. */

for (i = 0; i < n; ++i) {

PyObject *s;

if (i > 0) {

if (_PyUnicodeWriter_WriteASCIIString(&writer, ", ", 2) < 0)

goto error;

}

if (Py_EnterRecursiveCall(" while getting the repr of a tuple"))

goto error;

s = PyObject_Repr(v->ob_item[i]);

Py_LeaveRecursiveCall();

if (s == NULL)

goto error;

if (_PyUnicodeWriter_WriteStr(&writer, s) < 0) {

Py_DECREF(s);

goto error;

}

Py_DECREF(s);

}

writer.overallocate = 0;

if (n > 1) {

if (_PyUnicodeWriter_WriteChar(&writer, ')') < 0)

goto error;

}

else {

if (_PyUnicodeWriter_WriteASCIIString(&writer, ",)", 2) < 0)

goto error;

}

Py_ReprLeave((PyObject *)v);

return _PyUnicodeWriter_Finish(&writer);

error:

_PyUnicodeWriter_Dealloc(&writer);

Py_ReprLeave((PyObject *)v);

return NULL;

}

static Py_hash_t

tuplehash(PyTupleObject *v)

{

Py_uhash_t x; /* Unsigned for defined overflow behavior. */

Py_hash_t y;

Py_ssize_t len = Py_SIZE(v);

PyObject **p;

Py_uhash_t mult = _PyHASH_MULTIPLIER;

x = 0x345678UL;

p = v->ob_item;

while (--len >= 0) {

y = PyObject_Hash(*p++);

if (y == -1)

return -1;

x = (x ^ y) * mult;

/* the cast might truncate len; that doesn't change hash stability */

mult += (Py_hash_t)(82520UL + len + len);

}

x += 97531UL;

if (x == (Py_uhash_t)-1)

x = -2;

return x;

}

static Py_ssize_t

tuplelength(PyTupleObject *a)

{

return Py_SIZE(a);

}

static int

tuplecontains(PyTupleObject *a, PyObject *el)

{

Py_ssize_t i;

int cmp;

for (i = 0, cmp = 0 ; cmp == 0 && i < Py_SIZE(a); ++i)

cmp = PyObject_RichCompareBool(el, PyTuple_GET_ITEM(a, i),

Py_EQ);

return cmp;

}

static PyObject *

tupleitem(PyTupleObject *a, Py_ssize_t i)

{

if (i < 0 || i >= Py_SIZE(a)) {

PyErr_SetString(PyExc_IndexError, "tuple index out of range");

return NULL;

}

Py_INCREF(a->ob_item[i]);

return a->ob_item[i];

}

static PyObject *

tupleslice(PyTupleObject *a, Py_ssize_t ilow,

Py_ssize_t ihigh)

{

PyTupleObject *np;

PyObject **src, **dest;

Py_ssize_t i;

Py_ssize_t len;

if (ilow < 0)

ilow = 0;

if (ihigh > Py_SIZE(a))

ihigh = Py_SIZE(a);

if (ihigh < ilow)

ihigh = ilow;

if (ilow == 0 && ihigh == Py_SIZE(a) && PyTuple_CheckExact(a)) {

Py_INCREF(a);

return (PyObject *)a;

}

len = ihigh - ilow;

np = (PyTupleObject *)PyTuple_New(len);

if (np == NULL)

return NULL;

src = a->ob_item + ilow;

dest = np->ob_item;

for (i = 0; i < len; i++) {

PyObject *v = src[i];

Py_INCREF(v);

dest[i] = v;

}

return (PyObject *)np;

}

PyObject *

PyTuple_GetSlice(PyObject *op, Py_ssize_t i, Py_ssize_t j)

{

if (op == NULL || !PyTuple_Check(op)) {

PyErr_BadInternalCall();

return NULL;

}

return tupleslice((PyTupleObject *)op, i, j);

}

static PyObject *

tupleconcat(PyTupleObject *a, PyObject *bb)

{

Py_ssize_t size;

Py_ssize_t i;

PyObject **src, **dest;

PyTupleObject *np;

if (Py_SIZE(a) == 0 && PyTuple_CheckExact(bb)) {

Py_INCREF(bb);

return bb;

}

if (!PyTuple_Check(bb)) {

PyErr_Format(PyExc_TypeError,

"can only concatenate tuple (not \"%.200s\") to tuple",

Py_TYPE(bb)->tp_name);

return NULL;

}

#define b ((PyTupleObject *)bb)

if (Py_SIZE(b) == 0 && PyTuple_CheckExact(a)) {

Py_INCREF(a);

return (PyObject *)a;

}

if (Py_SIZE(a) > PY_SSIZE_T_MAX - Py_SIZE(b))

return PyErr_NoMemory();

size = Py_SIZE(a) + Py_SIZE(b);

np = (PyTupleObject *) PyTuple_New(size);

if (np == NULL) {

return NULL;

}

src = a->ob_item;

dest = np->ob_item;

for (i = 0; i < Py_SIZE(a); i++) {

PyObject *v = src[i];

Py_INCREF(v);

dest[i] = v;

}

src = b->ob_item;

dest = np->ob_item + Py_SIZE(a);

for (i = 0; i < Py_SIZE(b); i++) {

PyObject *v = src[i];

Py_INCREF(v);

dest[i] = v;

}

return (PyObject *)np;

#undef b

}

static PyObject *

tuplerepeat(PyTupleObject *a, Py_ssize_t n)

{

Py_ssize_t i, j;

Py_ssize_t size;

PyTupleObject *np;

PyObject **p, **items;

if (n < 0)

n = 0;

if (Py_SIZE(a) == 0 || n == 1) {

if (PyTuple_CheckExact(a)) {

/* Since tuples are immutable, we can return a shared

Py_INCREF(a);

return (PyObject *)a;

}

if (Py_SIZE(a) == 0)

return PyTuple_New(0);

}

if (n > PY_SSIZE_T_MAX / Py_SIZE(a))

return PyErr_NoMemory();

size = Py_SIZE(a) * n;

np = (PyTupleObject *) PyTuple_New(size);

if (np == NULL)

return NULL;

p = np->ob_item;

items = a->ob_item;

for (i = 0; i < n; i++) {

for (j = 0; j < Py_SIZE(a); j++) {

*p = items[j];

Py_INCREF(*p);

p++;

}

}

return (PyObject *) np;

}

static PyObject *

tuple_index_impl(PyTupleObject *self, PyObject *value, Py_ssize_t start,

Py_ssize_t stop)

{

Py_ssize_t i;

if (start < 0) {

start += Py_SIZE(self);

if (start < 0)

start = 0;

}

if (stop < 0) {

stop += Py_SIZE(self);

}

else if (stop > Py_SIZE(self)) {

stop = Py_SIZE(self);

}

for (i = start; i < stop; i++) {

int cmp = PyObject_RichCompareBool(self->ob_item[i], value, Py_EQ);

if (cmp > 0)

return PyLong_FromSsize_t(i);

else if (cmp < 0)

return NULL;

}

PyErr_SetString(PyExc_ValueError, "tuple.index(x): x not in tuple");

return NULL;

}

static PyObject *

tuple_count(PyTupleObject *self, PyObject *value)

{

Py_ssize_t count = 0;

Py_ssize_t i;

for (i = 0; i < Py_SIZE(self); i++) {

int cmp = PyObject_RichCompareBool(self->ob_item[i], value, Py_EQ);

if (cmp > 0)

count++;

else if (cmp < 0)

return NULL;

}

return PyLong_FromSsize_t(count);

}

static int

tupletraverse(PyTupleObject *o, visitproc visit, void *arg)

{

Py_ssize_t i;

for (i = Py_SIZE(o); --i >= 0; )

Py_VISIT(o->ob_item[i]);

return 0;

}

static PyObject *

tuplerichcompare(PyObject *v, PyObject *w, int op)

{

PyTupleObject *vt, *wt;

Py_ssize_t i;

Py_ssize_t vlen, wlen;

if (!PyTuple_Check(v) || !PyTuple_Check(w))

Py_RETURN_NOTIMPLEMENTED;

vt = (PyTupleObject *)v;

wt = (PyTupleObject *)w;

vlen = Py_SIZE(vt);

wlen = Py_SIZE(wt);

/* Note: the corresponding code for lists has an "early out" test

/* Search for the first index where items are different.

for (i = 0; i < vlen && i < wlen; i++) {

int k = PyObject_RichCompareBool(vt->ob_item[i],

wt->ob_item[i], Py_EQ);

if (k < 0)

return NULL;

if (!k)

break;

}

if (i >= vlen || i >= wlen) {

/* No more items to compare -- compare sizes */

int cmp;

PyObject *res;

switch (op) {

case Py_LT: cmp = vlen < wlen; break;

case Py_LE: cmp = vlen <= wlen; break;

case Py_EQ: cmp = vlen == wlen; break;

case Py_NE: cmp = vlen != wlen; break;

case Py_GT: cmp = vlen > wlen; break;

case Py_GE: cmp = vlen >= wlen; break;

default: return NULL; /* cannot happen */

}

if (cmp)

res = Py_True;

else

res = Py_False;

Py_INCREF(res);

return res;

}

/* We have an item that differs -- shortcuts for EQ/NE */

if (op == Py_EQ) {

Py_RETURN_FALSE;

}

if (op == Py_NE) {

Py_RETURN_TRUE;

}

/* Compare the final item again using the proper operator */

return PyObject_RichCompare(vt->ob_item[i], wt->ob_item[i], op);

}

static PyObject *

tuple_subtype_new(PyTypeObject *type, PyObject *iterable);

static PyObject *

tuple_new_impl(PyTypeObject *type, PyObject *iterable)

{

if (type != &PyTuple_Type)

return tuple_subtype_new(type, iterable);

if (iterable == NULL)

return PyTuple_New(0);

else

return PySequence_Tuple(iterable);

}

static PyObject *

tuple_subtype_new(PyTypeObject *type, PyObject *iterable)

{

PyObject *tmp, *newobj, *item;

Py_ssize_t i, n;

assert(PyType_IsSubtype(type, &PyTuple_Type));

tmp = tuple_new_impl(&PyTuple_Type, iterable);

if (tmp == NULL)

return NULL;

assert(PyTuple_Check(tmp));

newobj = type->tp_alloc(type, n = PyTuple_GET_SIZE(tmp));

if (newobj == NULL)

return NULL;

for (i = 0; i < n; i++) {

item = PyTuple_GET_ITEM(tmp, i);

Py_INCREF(item);

PyTuple_SET_ITEM(newobj, i, item);

}

Py_DECREF(tmp);

return newobj;

}

static PySequenceMethods tuple_as_sequence = {

(lenfunc)tuplelength, /* sq_length */

(binaryfunc)tupleconcat, /* sq_concat */

(ssizeargfunc)tuplerepeat, /* sq_repeat */

(ssizeargfunc)tupleitem, /* sq_item */

0, /* sq_slice */

0, /* sq_ass_item */

0, /* sq_ass_slice */

(objobjproc)tuplecontains, /* sq_contains */

};

static PyObject*

tuplesubscript(PyTupleObject* self, PyObject* item)

{

if (PyIndex_Check(item)) {

Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);

if (i == -1 && PyErr_Occurred())

return NULL;

if (i < 0)

i += PyTuple_GET_SIZE(self);

return tupleitem(self, i);

}

else if (PySlice_Check(item)) {

Py_ssize_t start, stop, step, slicelength, cur, i;

PyObject* result;

PyObject* it;

PyObject **src, **dest;

if (PySlice_Unpack(item, &start, &stop, &step) < 0) {

return NULL;

}

slicelength = PySlice_AdjustIndices(PyTuple_GET_SIZE(self), &start,

&stop, step);

if (slicelength <= 0) {

return PyTuple_New(0);

}

else if (start == 0 && step == 1 &&

slicelength == PyTuple_GET_SIZE(self) &&

PyTuple_CheckExact(self)) {

Py_INCREF(self);

return (PyObject *)self;

}

else {

result = PyTuple_New(slicelength);

if (!result) return NULL;

src = self->ob_item;

dest = ((PyTupleObject *)result)->ob_item;

for (cur = start, i = 0; i < slicelength;

cur += step, i++) {

it = src[cur];

Py_INCREF(it);

dest[i] = it;

}

return result;

}

}

else {

PyErr_Format(PyExc_TypeError,

"tuple indices must be integers or slices, not %.200s",

Py_TYPE(item)->tp_name);

return NULL;

}

}

static PyObject *

tuple___getnewargs___impl(PyTupleObject *self)

{

return Py_BuildValue("(N)", tupleslice(self, 0, Py_SIZE(self)));

}

static PyMethodDef tuple_methods[] = {

TUPLE___GETNEWARGS___METHODDEF

TUPLE_INDEX_METHODDEF

TUPLE_COUNT_METHODDEF

{NULL, NULL} /* sentinel */

};

static PyMappingMethods tuple_as_mapping = {

(lenfunc)tuplelength,

(binaryfunc)tuplesubscript,

0

};

static PyObject *tuple_iter(PyObject *seq);

PyTypeObject PyTuple_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

"tuple",

sizeof(PyTupleObject) - sizeof(PyObject *),

sizeof(PyObject *),

(destructor)tupledealloc, /* tp_dealloc */

0, /* tp_print */

0, /* tp_getattr */

0, /* tp_setattr */

0, /* tp_reserved */

(reprfunc)tuplerepr, /* tp_repr */

0, /* tp_as_number */

&tuple_as_sequence, /* tp_as_sequence */

&tuple_as_mapping, /* tp_as_mapping */

(hashfunc)tuplehash, /* 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 |

Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TUPLE_SUBCLASS, /* tp_flags */

tuple_new__doc__, /* tp_doc */

(traverseproc)tupletraverse, /* tp_traverse */

0, /* tp_clear */

tuplerichcompare, /* tp_richcompare */

0, /* tp_weaklistoffset */

tuple_iter, /* tp_iter */

0, /* tp_iternext */

tuple_methods, /* tp_methods */

0, /* tp_members */

0, /* tp_getset */

0, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* tp_descr_set */

0, /* tp_dictoffset */

0, /* tp_init */

0, /* tp_alloc */

tuple_new, /* tp_new */

PyObject_GC_Del, /* tp_free */

};

_PyTuple_Resize(PyObject **pv, Py_ssize_t newsize)

{

PyTupleObject *v;

PyTupleObject *sv;

Py_ssize_t i;

Py_ssize_t oldsize;

v = (PyTupleObject *) *pv;

if (v == NULL || Py_TYPE(v) != &PyTuple_Type ||

(Py_SIZE(v) != 0 && Py_REFCNT(v) != 1)) {

*pv = 0;

Py_XDECREF(v);

PyErr_BadInternalCall();

return -1;

}

oldsize = Py_SIZE(v);

if (oldsize == newsize)

return 0;

if (oldsize == 0) {

/* Empty tuples are often shared, so we should never

Py_DECREF(v);

*pv = PyTuple_New(newsize);

return *pv == NULL ? -1 : 0;

}

/* XXX UNREF/NEWREF interface should be more symmetrical */

_Py_DEC_REFTOTAL;

if (_PyObject_GC_IS_TRACKED(v))

_PyObject_GC_UNTRACK(v);

_Py_ForgetReference((PyObject *) v);

/* DECREF items deleted by shrinkage */

for (i = newsize; i < oldsize; i++) {

Py_CLEAR(v->ob_item[i]);

}

sv = PyObject_GC_Resize(PyTupleObject, v, newsize);

if (sv == NULL) {

*pv = NULL;

PyObject_GC_Del(v);

return -1;

}

_Py_NewReference((PyObject *) sv);

/* Zero out items added by growing */

if (newsize > oldsize)

memset(&sv->ob_item[oldsize], 0,

sizeof(*sv->ob_item) * (newsize - oldsize));

*pv = (PyObject *) sv;

_PyObject_GC_TRACK(sv);

return 0;

}

PyTuple_ClearFreeList(void)

{

int freelist_size = 0;

#if PyTuple_MAXSAVESIZE > 0

int i;

for (i = 1; i < PyTuple_MAXSAVESIZE; i++) {

PyTupleObject *p, *q;

p = free_list[i];

freelist_size += numfree[i];

free_list[i] = NULL;

numfree[i] = 0;

while (p) {

q = p;

p = (PyTupleObject *)(p->ob_item[0]);

PyObject_GC_Del(q);

}

}

return freelist_size;

}

PyTuple_Fini(void)

{

#if PyTuple_MAXSAVESIZE > 0

/* empty tuples are used all over the place and applications may

Py_CLEAR(free_list[0]);

(void)PyTuple_ClearFreeList();

#ifdef SHOW_TRACK_COUNT

show_track();

}

typedef struct {

PyObject_HEAD

Py_ssize_t it_index;

PyTupleObject *it_seq; /* Set to NULL when iterator is exhausted */

} tupleiterobject;

static void

tupleiter_dealloc(tupleiterobject *it)

{

_PyObject_GC_UNTRACK(it);

Py_XDECREF(it->it_seq);

PyObject_GC_Del(it);

}

static int

tupleiter_traverse(tupleiterobject *it, visitproc visit, void *arg)

{

Py_VISIT(it->it_seq);

return 0;

}

static PyObject *

tupleiter_next(tupleiterobject *it)

{

PyTupleObject *seq;

PyObject *item;

assert(it != NULL);

seq = it->it_seq;

if (seq == NULL)

return NULL;

assert(PyTuple_Check(seq));