void skiplist_delete(struct skiplist *list,char* data)
{
int i;
struct skipnode *update[MAXLEVEL+1], *x;
x = list->hdr;
for (i = list->level; i >= 0; i--) {
while (x->forward[i] != NIL
&& cmp_lt(x->forward[i]->key, data))
x = x->forward[i];
update[i] = x;
}
x = x->forward[0];
if (x == NIL || !cmp_eq(x->key, data))
return;
for (i = 0; i <= list->level; i++) {
if (update[i]->forward[i] != x)
break;
update[i]->forward[i] = x->forward[i];
}
free (x);
while ((list->level > 0)
&& (list->hdr->forward[list->level] == NIL))
list->level--;
}
static VALUE
cmp_between(VALUE x, VALUE min, VALUE max)
{
if (RTEST(cmp_lt(x, min))) return Qfalse;
if (RTEST(cmp_gt(x, max))) return Qfalse;
return Qtrue;
}
static mrb_value
cmp_lt_m(mrb_state *mrb, mrb_value x)
{
mrb_value y;
mrb_get_args(mrb, "o", &y);
return cmp_lt(mrb, x, y);
}
static mrb_value
cmp_between(mrb_state *mrb, mrb_value x)
{
mrb_value min, max;
mrb_get_args(mrb, "oo", &min, &max);
if (mrb_test(cmp_lt(mrb, x, min))) return mrb_false_value();
if (mrb_test(cmp_gt(mrb, x, max))) return mrb_false_value();
return mrb_true_value();
}
int skiplist_insert(struct skiplist *list,struct slice *sk,UINT val,OPT opt)
{
int i, new_level;
struct skipnode *update[MAXLEVEL+1];
struct skipnode *x;
char *key=sk->data;
if(!skiplist_notfull(list))
return 0;
x = list->hdr;
for (i = list->level; i >= 0; i--) {
while (x->forward[i] != NIL
&& cmp_lt(x->forward[i]->key, key))
x = x->forward[i];
update[i] = x;
}
x = x->forward[0];
if (x != NIL && cmp_eq(x->key, key)){
x->val = val;
x->opt = opt;
return(1);
}
for (new_level = 0; rand() < RAND_MAX/2 && new_level < MAXLEVEL; new_level++);
if (new_level > list->level) {
for (i = list->level + 1; i <= new_level; i++)
update[i] = NIL;
list->level = new_level;
}
if ((x =pool_alloc(list,sizeof(struct skipnode) + new_level*sizeof(struct skipnode *))) == 0)
__DEBUG("%s","memory *ERROR*");
memcpy(x->key,key,sk->len);
x->val=val;
x->opt=opt;
for (i = 0; i <= new_level; i++) {
x->forward[i] = update[i]->forward[i];
update[i]->forward[i] = x;
}
list->count++;
return(1);
}
struct skipnode *skiplist_lookup(struct skiplist *list,char* data)
{
int i;
struct skipnode *x = list->hdr;
for (i = list->level; i >= 0; i--) {
while (x->forward[i] != NIL
&& cmp_lt(x->forward[i]->key, data))
x = x->forward[i];
}
x = x->forward[0];
if (x != NIL && cmp_eq(x->key, data))
return (x);
return NULL;
}
static int
_siftup(PyListObject *heap, Py_ssize_t pos)
{
Py_ssize_t startpos, endpos, childpos, rightpos;
int cmp;
PyObject *newitem, *tmp;
assert(PyList_Check(heap));
endpos = PyList_GET_SIZE(heap);
startpos = pos;
if (pos >= endpos) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return -1;
}
newitem = PyList_GET_ITEM(heap, pos);
Py_INCREF(newitem);
/* Bubble up the smaller child until hitting a leaf. */
childpos = 2*pos + 1; /* leftmost child position */
while (childpos < endpos) {
/* Set childpos to index of smaller child. */
rightpos = childpos + 1;
if (rightpos < endpos) {
cmp = cmp_lt(
PyList_GET_ITEM(heap, childpos),
PyList_GET_ITEM(heap, rightpos));
if (cmp == -1) {
Py_DECREF(newitem);
return -1;
}
if (cmp == 0)
childpos = rightpos;
}
/* Move the smaller child up. */
tmp = PyList_GET_ITEM(heap, childpos);
Py_INCREF(tmp);
Py_DECREF(PyList_GET_ITEM(heap, pos));
PyList_SET_ITEM(heap, pos, tmp);
pos = childpos;
childpos = 2*pos + 1;
}
/* The leaf at pos is empty now. Put newitem there, and and bubble
it up to its final resting place (by sifting its parents down). */
Py_DECREF(PyList_GET_ITEM(heap, pos));
PyList_SET_ITEM(heap, pos, newitem);
return _siftdown(heap, startpos, pos);
}
static int
_siftup(PyListObject *heap, Py_ssize_t pos)
{
Py_ssize_t startpos, endpos, childpos, rightpos, limit;
PyObject *tmp1, *tmp2;
int cmp;
assert(PyList_Check(heap));
endpos = PyList_GET_SIZE(heap);
startpos = pos;
if (pos >= endpos) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return -1;
}
/* Bubble up the smaller child until hitting a leaf. */
limit = endpos / 2; /* smallest pos that has no child */
while (pos < limit) {
/* Set childpos to index of smaller child. */
childpos = 2*pos + 1; /* leftmost child position */
rightpos = childpos + 1;
if (rightpos < endpos) {
cmp = cmp_lt(
PyList_GET_ITEM(heap, childpos),
PyList_GET_ITEM(heap, rightpos));
if (cmp == -1)
return -1;
if (cmp == 0)
childpos = rightpos;
if (endpos != PyList_GET_SIZE(heap)) {
PyErr_SetString(PyExc_RuntimeError,
"list changed size during iteration");
return -1;
}
}
/* Move the smaller child up. */
tmp1 = PyList_GET_ITEM(heap, childpos);
tmp2 = PyList_GET_ITEM(heap, pos);
PyList_SET_ITEM(heap, childpos, tmp2);
PyList_SET_ITEM(heap, pos, tmp1);
pos = childpos;
}
/* Bubble it up to its final resting place (by sifting its parents down). */
return _siftdown(heap, startpos, pos);
}
static int
_siftdown(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
{
PyObject *newitem, *parent;
Py_ssize_t parentpos, size;
int cmp;
assert(PyList_Check(heap));
size = PyList_GET_SIZE(heap);
if (pos >= size) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return -1;
}
/* Follow the path to the root, moving parents down until finding
a place newitem fits. */
newitem = PyList_GET_ITEM(heap, pos);
while (pos > startpos) {
parentpos = (pos - 1) >> 1;
parent = PyList_GET_ITEM(heap, parentpos);
cmp = cmp_lt(newitem, parent);
if (cmp == -1)
return -1;
if (size != PyList_GET_SIZE(heap)) {
PyErr_SetString(PyExc_RuntimeError,
"list changed size during iteration");
return -1;
}
if (cmp == 0)
break;
parent = PyList_GET_ITEM(heap, parentpos);
newitem = PyList_GET_ITEM(heap, pos);
PyList_SET_ITEM(heap, parentpos, newitem);
PyList_SET_ITEM(heap, pos, parent);
pos = parentpos;
}
return 0;
}
static int
_siftdown(PyListObject *heap, Py_ssize_t startpos, Py_ssize_t pos)
{
PyObject *newitem, *parent;
int cmp;
Py_ssize_t parentpos;
assert(PyList_Check(heap));
if (pos >= PyList_GET_SIZE(heap)) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return -1;
}
newitem = PyList_GET_ITEM(heap, pos);
Py_INCREF(newitem);
/* Follow the path to the root, moving parents down until finding
a place newitem fits. */
while (pos > startpos){
parentpos = (pos - 1) >> 1;
parent = PyList_GET_ITEM(heap, parentpos);
cmp = cmp_lt(newitem, parent);
if (cmp == -1) {
Py_DECREF(newitem);
return -1;
}
if (cmp == 0)
break;
Py_INCREF(parent);
Py_DECREF(PyList_GET_ITEM(heap, pos));
PyList_SET_ITEM(heap, pos, parent);
pos = parentpos;
}
Py_DECREF(PyList_GET_ITEM(heap, pos));
PyList_SET_ITEM(heap, pos, newitem);
return 0;
}
static PyObject *
nsmallest(PyObject *self, PyObject *args)
{
PyObject *heap=NULL, *elem, *iterable, *los, *it, *oldelem;
Py_ssize_t i, n;
int cmp;
if (!PyArg_ParseTuple(args, "nO:nsmallest", &n, &iterable))
return NULL;
it = PyObject_GetIter(iterable);
if (it == NULL)
return NULL;
heap = PyList_New(0);
if (heap == NULL)
goto fail;
for (i=0 ; i<n ; i++ ){
elem = PyIter_Next(it);
if (elem == NULL) {
if (PyErr_Occurred())
goto fail;
else
goto sortit;
}
if (PyList_Append(heap, elem) == -1) {
Py_DECREF(elem);
goto fail;
}
Py_DECREF(elem);
}
n = PyList_GET_SIZE(heap);
if (n == 0)
goto sortit;
for (i=n/2-1 ; i>=0 ; i--)
if(_siftupmax((PyListObject *)heap, i) == -1)
goto fail;
los = PyList_GET_ITEM(heap, 0);
while (1) {
elem = PyIter_Next(it);
if (elem == NULL) {
if (PyErr_Occurred())
goto fail;
else
goto sortit;
}
cmp = cmp_lt(elem, los);
if (cmp == -1) {
Py_DECREF(elem);
goto fail;
}
if (cmp == 0) {
Py_DECREF(elem);
continue;
}
oldelem = PyList_GET_ITEM(heap, 0);
PyList_SET_ITEM(heap, 0, elem);
Py_DECREF(oldelem);
if (_siftupmax((PyListObject *)heap, 0) == -1)
goto fail;
los = PyList_GET_ITEM(heap, 0);
}
sortit:
if (PyList_Sort(heap) == -1)
goto fail;
Py_DECREF(it);
return heap;
fail:
Py_DECREF(it);
Py_XDECREF(heap);
return NULL;
}