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Issue9915: speeding up sorting with a key

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This commit is contained in:
Daniel Stutzbach 2010-12-02 21:55:33 +00:00
parent a0b44b5adb
commit 98338227a7
2 changed files with 241 additions and 226 deletions
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2
Misc/NEWS
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@ -10,6 +10,8 @@ What's New in Python 3.2 Beta 1?
Core and Builtins
-----------------
- Issue #9915: Speed up sorting with a key.
- Issue #9333: Expose os.symlink only when the SeCreateSymbolicLinkPrivilege
is held by the user's account, i.e., when the function can actually be used.

465
Objects/listobject.c
View File

@ -940,6 +940,66 @@ reverse_slice(PyObject **lo, PyObject **hi)
* pieces to this algorithm; read listsort.txt for overviews and details.
*/
/* A sortslice contains a pointer to an array of keys and a pointer to
* an array of corresponding values. In other words, keys[i]
* corresponds with values[i]. If values == NULL, then the keys are
* also the values.
*
* Several convenience routines are provided here, so that keys and
* values are always moved in sync.
*/
typedef struct {
PyObject **keys;
PyObject **values;
} sortslice;
Py_LOCAL_INLINE(void)
sortslice_copy(sortslice *s1, Py_ssize_t i, sortslice *s2, Py_ssize_t j)
{
s1->keys[i] = s2->keys[j];
if (s1->values != NULL)
s1->values[i] = s2->values[j];
}
Py_LOCAL_INLINE(void)
sortslice_copy_incr(sortslice *dst, sortslice *src) {
*dst->keys++ = *src->keys++;
if (dst->values != NULL)
*dst->values++ = *src->values++;
}
Py_LOCAL_INLINE(void)
sortslice_copy_decr(sortslice *dst, sortslice *src) {
*dst->keys-- = *src->keys--;
if (dst->values != NULL)
*dst->values-- = *src->values--;
}
Py_LOCAL_INLINE(void)
sortslice_memcpy(sortslice *s1, Py_ssize_t i, sortslice *s2, Py_ssize_t j,
Py_ssize_t n) {
memcpy(&s1->keys[i], &s2->keys[j], sizeof(PyObject *) * n);
if (s1->values != NULL)
memcpy(&s1->values[i], &s2->values[j], sizeof(PyObject *) * n);
}
Py_LOCAL_INLINE(void)
sortslice_memmove(sortslice *s1, Py_ssize_t i, sortslice *s2, Py_ssize_t j,
Py_ssize_t n) {
memmove(&s1->keys[i], &s2->keys[j], sizeof(PyObject *) * n);
if (s1->values != NULL)
memmove(&s1->values[i], &s2->values[j], sizeof(PyObject *) * n);
}
Py_LOCAL_INLINE(void)
sortslice_advance(sortslice *slice, Py_ssize_t n) {
slice->keys += n;
if (slice->values != NULL)
slice->values += n;
}
/* Comparison function: PyObject_RichCompareBool with Py_LT.
* Returns -1 on error, 1 if x < y, 0 if x >= y.
*/
@ -965,19 +1025,19 @@ reverse_slice(PyObject **lo, PyObject **hi)
the input (nothing is lost or duplicated).
*/
static int
binarysort(PyObject **lo, PyObject **hi, PyObject **start)
binarysort(sortslice lo, PyObject **hi, PyObject **start)
{
register Py_ssize_t k;
register PyObject **l, **p, **r;
register PyObject *pivot;
assert(lo <= start && start <= hi);
assert(lo.keys <= start && start <= hi);
/* assert [lo, start) is sorted */
if (lo == start)
if (lo.keys == start)
++start;
for (; start < hi; ++start) {
/* set l to where *start belongs */
l = lo;
l = lo.keys;
r = start;
pivot = *r;
/* Invariants:
@ -1004,6 +1064,15 @@ binarysort(PyObject **lo, PyObject **hi, PyObject **start)
for (p = start; p > l; --p)
*p = *(p-1);
*l = pivot;
if (lo.values != NULL) {
Py_ssize_t offset = lo.values - lo.keys;
p = start + offset;
pivot = *p;
l += offset;
for (p = start + offset; p > l; --p)
*p = *(p-1);
*l = pivot;
}
}
return 0;
@ -1272,7 +1341,7 @@ fail:
* a convenient way to pass state around among the helper functions.
*/
struct s_slice {
PyObject **base;
sortslice base;
Py_ssize_t len;
};
@ -1286,7 +1355,7 @@ typedef struct s_MergeState {
/* 'a' is temp storage to help with merges. It contains room for
* alloced entries.
*/
PyObject **a; /* may point to temparray below */
sortslice a; /* may point to temparray below */
Py_ssize_t alloced;
/* A stack of n pending runs yet to be merged. Run #i starts at
@ -1307,11 +1376,29 @@ typedef struct s_MergeState {
/* Conceptually a MergeState's constructor. */
static void
merge_init(MergeState *ms)
merge_init(MergeState *ms, int list_size, int has_keyfunc)
{
assert(ms != NULL);
ms->a = ms->temparray;
ms->alloced = MERGESTATE_TEMP_SIZE;
if (has_keyfunc) {
/* The temporary space for merging will need at most half the list
* size rounded up. Use the minimum possible space so we can use the
* rest of temparray for other things. In particular, if there is
* enough extra space, listsort() will use it to store the keys.
*/
ms->alloced = (list_size + 1) / 2;
/* ms->alloced describes how many keys will be stored at
ms->temparray, but we also need to store the values. Hence,
ms->alloced is capped at half of MERGESTATE_TEMP_SIZE. */
if (MERGESTATE_TEMP_SIZE / 2 < ms->alloced)
ms->alloced = MERGESTATE_TEMP_SIZE / 2;
ms->a.values = &ms->temparray[ms->alloced];
}
else {
ms->alloced = MERGESTATE_TEMP_SIZE;
ms->a.values = NULL;
}
ms->a.keys = ms->temparray;
ms->n = 0;
ms->min_gallop = MIN_GALLOP;
}
@ -1324,10 +1411,8 @@ static void
merge_freemem(MergeState *ms)
{
assert(ms != NULL);
if (ms->a != ms->temparray)
PyMem_Free(ms->a);
ms->a = ms->temparray;
ms->alloced = MERGESTATE_TEMP_SIZE;
if (ms->a.keys != ms->temparray)
PyMem_Free(ms->a.keys);
}
/* Ensure enough temp memory for 'need' array slots is available.
@ -1336,52 +1421,60 @@ merge_freemem(MergeState *ms)
static int
merge_getmem(MergeState *ms, Py_ssize_t need)
{
int multiplier;
assert(ms != NULL);
if (need <= ms->alloced)
return 0;
multiplier = ms->a.values != NULL ? 2 : 1;
/* Don't realloc! That can cost cycles to copy the old data, but
* we don't care what's in the block.
*/
merge_freemem(ms);
if ((size_t)need > PY_SSIZE_T_MAX / sizeof(PyObject*)) {
if ((size_t)need > PY_SSIZE_T_MAX / sizeof(PyObject*) / multiplier) {
PyErr_NoMemory();
return -1;
}
ms->a = (PyObject **)PyMem_Malloc(need * sizeof(PyObject*));
if (ms->a) {
ms->a.keys = (PyObject**)PyMem_Malloc(multiplier * need
* sizeof(PyObject *));
if (ms->a.keys != NULL) {
ms->alloced = need;
if (ms->a.values != NULL)
ms->a.values = &ms->a.keys[need];
return 0;
}
PyErr_NoMemory();
merge_freemem(ms); /* reset to sane state */
return -1;
}
#define MERGE_GETMEM(MS, NEED) ((NEED) <= (MS)->alloced ? 0 : \
merge_getmem(MS, NEED))
/* Merge the na elements starting at pa with the nb elements starting at pb
* in a stable way, in-place. na and nb must be > 0, and pa + na == pb.
* Must also have that *pb < *pa, that pa[na-1] belongs at the end of the
* merge, and should have na <= nb. See listsort.txt for more info.
* Return 0 if successful, -1 if error.
/* Merge the na elements starting at ssa with the nb elements starting at
* ssb.keys = ssa.keys + na in a stable way, in-place. na and nb must be > 0.
* Must also have that ssa.keys[na-1] belongs at the end of the merge, and
* should have na <= nb. See listsort.txt for more info. Return 0 if
* successful, -1 if error.
*/
static Py_ssize_t
merge_lo(MergeState *ms, PyObject **pa, Py_ssize_t na,
PyObject **pb, Py_ssize_t nb)
merge_lo(MergeState *ms, sortslice ssa, Py_ssize_t na,
sortslice ssb, Py_ssize_t nb)
{
Py_ssize_t k;
PyObject **dest;
sortslice dest;
int result = -1; /* guilty until proved innocent */
Py_ssize_t min_gallop;
assert(ms && pa && pb && na > 0 && nb > 0 && pa + na == pb);
assert(ms && ssa.keys && ssb.keys && na > 0 && nb > 0);
assert(ssa.keys + na == ssb.keys);
if (MERGE_GETMEM(ms, na) < 0)
return -1;
memcpy(ms->a, pa, na * sizeof(PyObject*));
dest = pa;
pa = ms->a;
sortslice_memcpy(&ms->a, 0, &ssa, 0, na);
dest = ssa;
ssa = ms->a;
*dest++ = *pb++;
sortslice_copy_incr(&dest, &ssb);
--nb;
if (nb == 0)
goto Succeed;
@ -1398,11 +1491,11 @@ merge_lo(MergeState *ms, PyObject **pa, Py_ssize_t na,
*/
for (;;) {
assert(na > 1 && nb > 0);
k = ISLT(*pb, *pa);
k = ISLT(ssb.keys[0], ssa.keys[0]);
if (k) {
if (k < 0)
goto Fail;
*dest++ = *pb++;
sortslice_copy_incr(&dest, &ssb);
++bcount;
acount = 0;
--nb;
@ -1412,7 +1505,7 @@ merge_lo(MergeState *ms, PyObject **pa, Py_ssize_t na,
break;
}
else {
*dest++ = *pa++;
sortslice_copy_incr(&dest, &ssa);
++acount;
bcount = 0;
--na;
@ -1433,14 +1526,14 @@ merge_lo(MergeState *ms, PyObject **pa, Py_ssize_t na,
assert(na > 1 && nb > 0);
min_gallop -= min_gallop > 1;
ms->min_gallop = min_gallop;
k = gallop_right(*pb, pa, na, 0);
k = gallop_right(ssb.keys[0], ssa.keys, na, 0);
acount = k;
if (k) {
if (k < 0)
goto Fail;
memcpy(dest, pa, k * sizeof(PyObject *));
dest += k;
pa += k;
sortslice_memcpy(&dest, 0, &ssa, 0, k);
sortslice_advance(&dest, k);
sortslice_advance(&ssa, k);
na -= k;
if (na == 1)
goto CopyB;
@ -1451,24 +1544,24 @@ merge_lo(MergeState *ms, PyObject **pa, Py_ssize_t na,
if (na == 0)
goto Succeed;
}
*dest++ = *pb++;
sortslice_copy_incr(&dest, &ssb);
--nb;
if (nb == 0)
goto Succeed;
k = gallop_left(*pa, pb, nb, 0);
k = gallop_left(ssa.keys[0], ssb.keys, nb, 0);
bcount = k;
if (k) {
if (k < 0)
goto Fail;
memmove(dest, pb, k * sizeof(PyObject *));
dest += k;
pb += k;
sortslice_memmove(&dest, 0, &ssb, 0, k);
sortslice_advance(&dest, k);
sortslice_advance(&ssb, k);
nb -= k;
if (nb == 0)
goto Succeed;
}
*dest++ = *pa++;
sortslice_copy_incr(&dest, &ssa);
--na;
if (na == 1)
goto CopyB;
@ -1480,43 +1573,46 @@ Succeed:
result = 0;
Fail:
if (na)
memcpy(dest, pa, na * sizeof(PyObject*));
sortslice_memcpy(&dest, 0, &ssa, 0, na);
return result;
CopyB:
assert(na == 1 && nb > 0);
/* The last element of pa belongs at the end of the merge. */
memmove(dest, pb, nb * sizeof(PyObject *));
dest[nb] = *pa;
/* The last element of ssa belongs at the end of the merge. */
sortslice_memmove(&dest, 0, &ssb, 0, nb);
sortslice_copy(&dest, nb, &ssa, 0);
return 0;
}
/* Merge the na elements starting at pa with the nb elements starting at pb
* in a stable way, in-place. na and nb must be > 0, and pa + na == pb.
* Must also have that *pb < *pa, that pa[na-1] belongs at the end of the
* merge, and should have na >= nb. See listsort.txt for more info.
* Return 0 if successful, -1 if error.
/* Merge the na elements starting at pa with the nb elements starting at
* ssb.keys = ssa.keys + na in a stable way, in-place. na and nb must be > 0.
* Must also have that ssa.keys[na-1] belongs at the end of the merge, and
* should have na >= nb. See listsort.txt for more info. Return 0 if
* successful, -1 if error.
*/
static Py_ssize_t
merge_hi(MergeState *ms, PyObject **pa, Py_ssize_t na, PyObject **pb, Py_ssize_t nb)
merge_hi(MergeState *ms, sortslice ssa, Py_ssize_t na,
sortslice ssb, Py_ssize_t nb)
{
Py_ssize_t k;
PyObject **dest;
sortslice dest, basea, baseb;
int result = -1; /* guilty until proved innocent */
PyObject **basea;
PyObject **baseb;
Py_ssize_t min_gallop;
assert(ms && pa && pb && na > 0 && nb > 0 && pa + na == pb);
assert(ms && ssa.keys && ssb.keys && na > 0 && nb > 0);
assert(ssa.keys + na == ssb.keys);
if (MERGE_GETMEM(ms, nb) < 0)
return -1;
dest = pb + nb - 1;
memcpy(ms->a, pb, nb * sizeof(PyObject*));
basea = pa;
dest = ssb;
sortslice_advance(&dest, nb-1);
sortslice_memcpy(&ms->a, 0, &ssb, 0, nb);
basea = ssa;
baseb = ms->a;
pb = ms->a + nb - 1;
pa += na - 1;
ssb.keys = ms->a.keys + nb - 1;
if (ssb.values != NULL)
ssb.values = ms->a.values + nb - 1;
sortslice_advance(&ssa, na - 1);
*dest-- = *pa--;
sortslice_copy_decr(&dest, &ssa);
--na;
if (na == 0)
goto Succeed;
@ -1533,11 +1629,11 @@ merge_hi(MergeState *ms, PyObject **pa, Py_ssize_t na, PyObject **pb, Py_ssize_t
*/
for (;;) {
assert(na > 0 && nb > 1);
k = ISLT(*pb, *pa);
k = ISLT(ssb.keys[0], ssa.keys[0]);
if (k) {
if (k < 0)
goto Fail;
*dest-- = *pa--;
sortslice_copy_decr(&dest, &ssa);
++acount;
bcount = 0;
--na;
@ -1547,7 +1643,7 @@ merge_hi(MergeState *ms, PyObject **pa, Py_ssize_t na, PyObject **pb, Py_ssize_t
break;
}
else {
*dest-- = *pb--;
sortslice_copy_decr(&dest, &ssb);
++bcount;
acount = 0;
--nb;
@ -1568,33 +1664,33 @@ merge_hi(MergeState *ms, PyObject **pa, Py_ssize_t na, PyObject **pb, Py_ssize_t
assert(na > 0 && nb > 1);
min_gallop -= min_gallop > 1;
ms->min_gallop = min_gallop;
k = gallop_right(*pb, basea, na, na-1);
k = gallop_right(ssb.keys[0], basea.keys, na, na-1);
if (k < 0)
goto Fail;
k = na - k;
acount = k;
if (k) {
dest -= k;
pa -= k;
memmove(dest+1, pa+1, k * sizeof(PyObject *));
sortslice_advance(&dest, -k);
sortslice_advance(&ssa, -k);
sortslice_memmove(&dest, 1, &ssa, 1, k);
na -= k;
if (na == 0)
goto Succeed;
}
*dest-- = *pb--;
sortslice_copy_decr(&dest, &ssb);
--nb;
if (nb == 1)
goto CopyA;
k = gallop_left(*pa, baseb, nb, nb-1);
k = gallop_left(ssa.keys[0], baseb.keys, nb, nb-1);
if (k < 0)
goto Fail;
k = nb - k;
bcount = k;
if (k) {
dest -= k;
pb -= k;
memcpy(dest+1, pb+1, k * sizeof(PyObject *));
sortslice_advance(&dest, -k);
sortslice_advance(&ssb, -k);
sortslice_memcpy(&dest, 1, &ssb, 1, k);
nb -= k;
if (nb == 1)
goto CopyA;
@ -1605,7 +1701,7 @@ merge_hi(MergeState *ms, PyObject **pa, Py_ssize_t na, PyObject **pb, Py_ssize_t
if (nb == 0)
goto Succeed;
}
*dest-- = *pa--;
sortslice_copy_decr(&dest, &ssa);
--na;
if (na == 0)
goto Succeed;
@ -1617,15 +1713,15 @@ Succeed:
result = 0;
Fail:
if (nb)
memcpy(dest-(nb-1), baseb, nb * sizeof(PyObject*));
sortslice_memcpy(&dest, -(nb-1), &baseb, 0, nb);
return result;
CopyA:
assert(nb == 1 && na > 0);
/* The first element of pb belongs at the front of the merge. */
dest -= na;
pa -= na;
memmove(dest+1, pa+1, na * sizeof(PyObject *));
*dest = *pb;
/* The first element of ssb belongs at the front of the merge. */
sortslice_memmove(&dest, 1-na, &ssa, 1-na, na);
sortslice_advance(&dest, -na);
sortslice_advance(&ssa, -na);
sortslice_copy(&dest, 0, &ssb, 0);
return 0;
}
@ -1635,7 +1731,7 @@ CopyA:
static Py_ssize_t
merge_at(MergeState *ms, Py_ssize_t i)
{
PyObject **pa, **pb;
sortslice ssa, ssb;
Py_ssize_t na, nb;
Py_ssize_t k;
@ -1644,12 +1740,12 @@ merge_at(MergeState *ms, Py_ssize_t i)
assert(i >= 0);
assert(i == ms->n - 2 || i == ms->n - 3);
pa = ms->pending[i].base;
ssa = ms->pending[i].base;
na = ms->pending[i].len;
pb = ms->pending[i+1].base;
ssb = ms->pending[i+1].base;
nb = ms->pending[i+1].len;
assert(na > 0 && nb > 0);
assert(pa + na == pb);
assert(ssa.keys + na == ssb.keys);
/* Record the length of the combined runs; if i is the 3rd-last
* run now, also slide over the last run (which isn't involved
@ -1663,10 +1759,10 @@ merge_at(MergeState *ms, Py_ssize_t i)
/* Where does b start in a? Elements in a before that can be
* ignored (already in place).
*/
k = gallop_right(*pb, pa, na, 0);
k = gallop_right(*ssb.keys, ssa.keys, na, 0);
if (k < 0)
return -1;
pa += k;
sortslice_advance(&ssa, k);
na -= k;
if (na == 0)
return 0;
@ -1674,7 +1770,7 @@ merge_at(MergeState *ms, Py_ssize_t i)
/* Where does a end in b? Elements in b after that can be
* ignored (already in place).
*/
nb = gallop_left(pa[na-1], pb, nb, nb-1);
nb = gallop_left(ssa.keys[na-1], ssb.keys, nb, nb-1);
if (nb <= 0)
return nb;
@ -1682,9 +1778,9 @@ merge_at(MergeState *ms, Py_ssize_t i)
* min(na, nb) elements.
*/
if (na <= nb)
return merge_lo(ms, pa, na, pb, nb);
return merge_lo(ms, ssa, na, ssb, nb);
else
return merge_hi(ms, pa, na, pb, nb);
return merge_hi(ms, ssa, na, ssb, nb);
}
/* Examine the stack of runs waiting to be merged, merging adjacent runs
@ -1765,103 +1861,12 @@ merge_compute_minrun(Py_ssize_t n)
return n + r;
}
/* Special wrapper to support stable sorting using the decorate-sort-undecorate
pattern. Holds a key which is used for comparisons and the original record
which is returned during the undecorate phase. By exposing only the key
during comparisons, the underlying sort stability characteristics are left
unchanged. Also, the comparison function will only see the key instead of
a full record. */
typedef struct {
PyObject_HEAD
PyObject *key;
PyObject *value;
} sortwrapperobject;
PyDoc_STRVAR(sortwrapper_doc, "Object wrapper with a custom sort key.");
static PyObject *
sortwrapper_richcompare(sortwrapperobject *, sortwrapperobject *, int);
static void
sortwrapper_dealloc(sortwrapperobject *);
PyTypeObject PySortWrapper_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"sortwrapper", /* tp_name */
sizeof(sortwrapperobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)sortwrapper_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, /* tp_flags */
sortwrapper_doc, /* tp_doc */
0, /* tp_traverse */
0, /* tp_clear */
(richcmpfunc)sortwrapper_richcompare, /* tp_richcompare */
};
static PyObject *
sortwrapper_richcompare(sortwrapperobject *a, sortwrapperobject *b, int op)
reverse_sortslice(sortslice *s, Py_ssize_t n)
{
if (!PyObject_TypeCheck(b, &PySortWrapper_Type)) {
PyErr_SetString(PyExc_TypeError,
"expected a sortwrapperobject");
return NULL;
}
return PyObject_RichCompare(a->key, b->key, op);
}
static void
sortwrapper_dealloc(sortwrapperobject *so)
{
Py_XDECREF(so->key);
Py_XDECREF(so->value);
PyObject_Del(so);
}
/* Returns a new reference to a sortwrapper.
Consumes the references to the two underlying objects. */
static PyObject *
build_sortwrapper(PyObject *key, PyObject *value)
{
sortwrapperobject *so;
so = PyObject_New(sortwrapperobject, &PySortWrapper_Type);
if (so == NULL)
return NULL;
so->key = key;
so->value = value;
return (PyObject *)so;
}
/* Returns a new reference to the value underlying the wrapper. */
static PyObject *
sortwrapper_getvalue(PyObject *so)
{
PyObject *value;
if (!PyObject_TypeCheck(so, &PySortWrapper_Type)) {
PyErr_SetString(PyExc_TypeError,
"expected a sortwrapperobject");
return NULL;
}
value = ((sortwrapperobject *)so)->value;
Py_INCREF(value);
return value;
reverse_slice(s->keys, &s->keys[n]);
if (s->values != NULL)
reverse_slice(s->values, &s->values[n]);
}
/* An adaptive, stable, natural mergesort. See listsort.txt.
@ -1873,9 +1878,9 @@ static PyObject *
listsort(PyListObject *self, PyObject *args, PyObject *kwds)
{
MergeState ms;
PyObject **lo, **hi;
Py_ssize_t nremaining;
Py_ssize_t minrun;
sortslice lo;
Py_ssize_t saved_ob_size, saved_allocated;
PyObject **saved_ob_item;
PyObject **final_ob_item;
@ -1883,8 +1888,8 @@ listsort(PyListObject *self, PyObject *args, PyObject *kwds)
int reverse = 0;
PyObject *keyfunc = NULL;
Py_ssize_t i;
PyObject *key, *value, *kvpair;
static char *kwlist[] = {"key", "reverse", 0};
PyObject **keys;
assert(self != NULL);
assert (PyList_Check(self));
@ -1913,28 +1918,36 @@ listsort(PyListObject *self, PyObject *args, PyObject *kwds)
self->ob_item = NULL;
self->allocated = -1; /* any operation will reset it to >= 0 */
if (keyfunc != NULL) {
for (i=0 ; i < saved_ob_size ; i++) {
value = saved_ob_item[i];
key = PyObject_CallFunctionObjArgs(keyfunc, value,
NULL);
if (key == NULL) {
for (i=i-1 ; i>=0 ; i--) {
kvpair = saved_ob_item[i];
value = sortwrapper_getvalue(kvpair);
saved_ob_item[i] = value;
Py_DECREF(kvpair);
}
goto dsu_fail;
}
kvpair = build_sortwrapper(key, value);
if (kvpair == NULL)
goto dsu_fail;
saved_ob_item[i] = kvpair;
if (keyfunc == NULL) {
keys = NULL;
lo.keys = saved_ob_item;
lo.values = NULL;
}
else {
if (saved_ob_size < MERGESTATE_TEMP_SIZE/2)
/* Leverage stack space we allocated but won't otherwise use */
keys = &ms.temparray[saved_ob_size+1];
else {
keys = PyMem_MALLOC(sizeof(PyObject *) * saved_ob_size);
if (keys == NULL)
return NULL;
}
for (i = 0; i < saved_ob_size ; i++) {
keys[i] = PyObject_CallFunctionObjArgs(keyfunc, saved_ob_item[i],
NULL);
if (keys[i] == NULL) {
for (i=i-1 ; i>=0 ; i--)
Py_DECREF(keys[i]);
goto keyfunc_fail;
}
}
lo.keys = keys;
lo.values = saved_ob_item;
}
merge_init(&ms);
merge_init(&ms, saved_ob_size, keys != NULL);
nremaining = saved_ob_size;
if (nremaining < 2)
@ -1942,30 +1955,31 @@ listsort(PyListObject *self, PyObject *args, PyObject *kwds)
/* Reverse sort stability achieved by initially reversing the list,
applying a stable forward sort, then reversing the final result. */
if (reverse)
reverse_slice(saved_ob_item, saved_ob_item + saved_ob_size);
if (reverse) {
if (keys != NULL)
reverse_slice(&keys[0], &keys[saved_ob_size]);
reverse_slice(&saved_ob_item[0], &saved_ob_item[saved_ob_size]);
}
/* March over the array once, left to right, finding natural runs,
* and extending short natural runs to minrun elements.
*/
lo = saved_ob_item;
hi = lo + nremaining;
minrun = merge_compute_minrun(nremaining);
do {
int descending;
Py_ssize_t n;
/* Identify next run. */
n = count_run(lo, hi, &descending);
n = count_run(lo.keys, lo.keys + nremaining, &descending);
if (n < 0)
goto fail;
if (descending)
reverse_slice(lo, lo + n);
reverse_sortslice(&lo, n);
/* If short, extend to min(minrun, nremaining). */
if (n < minrun) {
const Py_ssize_t force = nremaining <= minrun ?
nremaining : minrun;
if (binarysort(lo, lo + force, lo + n) < 0)
if (binarysort(lo, lo.keys + force, lo.keys + n) < 0)
goto fail;
n = force;
}
@ -1977,27 +1991,27 @@ listsort(PyListObject *self, PyObject *args, PyObject *kwds)
if (merge_collapse(&ms) < 0)
goto fail;
/* Advance to find next run. */
lo += n;
sortslice_advance(&lo, n);
nremaining -= n;
} while (nremaining);
assert(lo == hi);
if (merge_force_collapse(&ms) < 0)
goto fail;
assert(ms.n == 1);
assert(ms.pending[0].base == saved_ob_item);
assert(keys == NULL
? ms.pending[0].base.keys == saved_ob_item
: ms.pending[0].base.keys == &keys[0]);
assert(ms.pending[0].len == saved_ob_size);
lo = ms.pending[0].base;
succeed:
result = Py_None;
fail:
if (keyfunc != NULL) {
for (i=0 ; i < saved_ob_size ; i++) {
kvpair = saved_ob_item[i];
value = sortwrapper_getvalue(kvpair);
saved_ob_item[i] = value;
Py_DECREF(kvpair);
}
if (keys != NULL) {
for (i = 0; i < saved_ob_size; i++)
Py_DECREF(keys[i]);
if (keys != &ms.temparray[saved_ob_size+1])
PyMem_FREE(keys);
}
if (self->allocated != -1 && result != NULL) {
@ -2013,7 +2027,7 @@ fail:
merge_freemem(&ms);
dsu_fail:
keyfunc_fail:
final_ob_item = self->ob_item;
i = Py_SIZE(self);
Py_SIZE(self) = saved_ob_size;
@ -2862,4 +2876,3 @@ listreviter_len(listreviterobject *it)
len = 0;
return PyLong_FromSsize_t(len);
}