unsigned _tDosCreate(_TCHAR *pathP, unsigned attr, int *handlep, unsigned disp)
{
HANDLE handle;
SECURITY_ATTRIBUTES sec; /* used only to set inheritance flag */
unsigned rc, oflag;
/* Set the inheritance flag in the security attributes.
*/
sec.nLength = sizeof(sec);
sec.lpSecurityDescriptor = NULL;
sec.bInheritHandle = TRUE;
/* Create the file.
*/
if ((handle = CreateFile(pathP, GENERIC_READ|GENERIC_WRITE,
FILE_SHARE_READ|FILE_SHARE_WRITE, &sec, disp,
attr, NULL)) == (HANDLE)-1)
return (__DOSerror());
/* Save the open flags and find free file handle table slot.
* Save the NT file handle in the table, return the table index.
*/
oflag = O_BINARY;
if (__isatty_osfhandle((long)handle))
oflag |= O_DEVICE;
if ((attr & FILE_ATTRIBUTE_READONLY) == 0)
oflag |= _O_WRITABLE; /* fstat() uses this bit */
_lock_all_handles();
if ((*handlep = _get_handle((long)handle, oflag)) == -1)
{
__IOerror(rc = ERROR_TOO_MANY_OPEN_FILES);
CloseHandle(handle);
DeleteFile(pathP);
}
else
rc = 0;
_unlock_all_handles();
return rc;
}
void _process_weak_node(bp_tree * tree, bp_node * p)
{
int i = _index_of_child(p);
bp_node * parent = p->parent;
if (i < parent->n - 1) { // has right sibling
bp_node * rsib = parent->ptr[i+1];
if (rsib->n == 3) { // right sibling has enough children
// move right sibling's left child to p
p->key[1] = rsib->key[0];
p->ptr[1] = rsib->ptr[0];
if (p->ptr[1]) {
p->ptr[1]->parent = p;
}
++p->n;
// update p's max key in parent
int old_max = p->key[0], new_max = p->key[1];
_update_key(parent, old_max, new_max);
// fill blank location in rsib
rsib->key[0] = rsib->key[1];
rsib->key[1] = rsib->key[2];
rsib->ptr[0] = rsib->ptr[1];
rsib->ptr[1] = rsib->ptr[2];
--rsib->n;
}
else { // no enough children in right sibling
// move data in p to right sibling
for (int j = rsib->n; j > 0; --j) {
rsib->key[j] = rsib->key[j-1];
rsib->ptr[j] = rsib->ptr[j-1];
}
rsib->key[0] = p->key[0];
rsib->ptr[0] = p->ptr[0];
if (rsib->ptr[0]) {
rsib->ptr[0]->parent = rsib;
}
++rsib->n;
// remove p then update key in parent, and don't forget leaf links
if (_is_leaf(p)) {
bp_node ** handle = _get_handle(tree, p);
*handle = rsib;
}
delete p;
for (int j = i + 1; j < parent->n; ++j) {
parent->key[j-1] = parent->key[j];
parent->ptr[j-1] = parent->ptr[j];
}
--parent->n;
}
}
else { // p has no right sibling, just left
bp_node * Lsib = parent->ptr[i-1];
if (Lsib->n == 3) { // left sibling has enouph children
// move left sibling's right child to p
p->key[1] = p->key[0];
p->ptr[1] = p->ptr[0];
p->key[0] = Lsib->key[Lsib->n-1];
p->ptr[0] = Lsib->ptr[Lsib->n-1];
if (p->ptr[0]) {
p->ptr[0]->parent = p;
}
++p->n;
// update left sibling
int old_max = Lsib->key[Lsib->n-1];
int new_max = Lsib->key[Lsib->n-2];
_update_key(parent, old_max, new_max);
--Lsib->n;
}
else { // no enough children in left sibling
// move data in p to left sibling
Lsib->key[Lsib->n] = p->key[0];
Lsib->ptr[Lsib->n] = p->ptr[0];
if (p->ptr[0]) {
p->ptr[0]->parent = Lsib;
}
++Lsib->n;
// update key of left sibling in parent
int old_key = Lsib->key[Lsib->n-2];
int new_key = Lsib->key[Lsib->n-1];
_update_key(parent, old_key, new_key);
// drop p then update key in parent, and don't forget leaf links
if (_is_leaf(p)) {
Lsib->next = p->next;
}
delete p;
for (int j = i + 1; j < parent->n; ++j) {
parent->key[j-1] = parent->key[j];
parent->ptr[j-1] = parent->ptr[j];
}
--parent->n;
}
}
}
