/*
** _bucket_get
**
** Search a bucket for a given key.
**
** Arguments
** self The bucket
** keyarg The key to look for
** has_key Boolean; if true, return a true/false result; else return
** the value associated with the key.
**
** Return
** If has_key:
** Returns the Python int 0 if the key is absent, else returns
** has_key itself as a Python int. A BTree caller generally passes
** the depth of the bucket for has_key, so a true result returns
** the bucket depth then.
** Note that has_key should be tree when searching set buckets.
** If not has_key:
** If the key is present, returns the associated value, and the
** caller owns the reference. Else returns NULL and sets KeyError.
** Whether or not has_key:
** If a comparison sets an exception, returns NULL.
*/
static PyObject *
_bucket_get(Bucket *self, PyObject *keyarg, int has_key)
{
int i, cmp;
KEY_TYPE key;
PyObject *r = NULL;
int copied = 1;
COPY_KEY_FROM_ARG(key, keyarg, copied);
UNLESS (copied) return NULL;
PER_USE_OR_RETURN(self, NULL);
BUCKET_SEARCH(i, cmp, self, key, goto Done);
if (has_key)
r = PyInt_FromLong(cmp ? 0 : has_key);
else {
if (cmp == 0) {
COPY_VALUE_TO_OBJECT(r, self->values[i]);
}
else
PyErr_SetObject(PyExc_KeyError, keyarg);
}
Done:
PER_ALLOW_DEACTIVATION(self);
PER_ACCESSED(self);
return r;
}
static PyObject *
bucket_toString(PyObject *oself)
{
Bucket *self = (Bucket *)oself;
PyObject *items = NULL;
int len;
PER_USE_OR_RETURN(self, NULL);
len = self->len;
items = PyString_FromStringAndSize(NULL, len*8);
if (items == NULL)
goto err;
memcpy(PyString_AS_STRING(items), self->keys, len*2);
memcpy(PyString_AS_STRING(items)+len*2, self->values, len*6);
PER_UNUSE(self);
return items;
err:
PER_UNUSE(self);
Py_XDECREF(items);
return NULL;
}
/* Search for the bucket immediately preceding *current, in the bucket chain
* starting at first. current, *current and first must not be NULL.
*
* Return:
* 1 *current holds the correct bucket; this is a borrowed reference
* 0 no such bucket exists; *current unaltered
* -1 error; *current unaltered
*/
static int
PreviousBucket(Bucket **current, Bucket *first)
{
Bucket *trailing = NULL; /* first travels; trailing follows it */
int result = 0;
assert(current && *current && first);
if (first == *current)
return 0;
do {
trailing = first;
PER_USE_OR_RETURN(first, -1);
first = first->next;
((trailing)->state==cPersistent_STICKY_STATE
&&
((trailing)->state=cPersistent_UPTODATE_STATE));
PER_ACCESSED(trailing);
if (first == *current) {
*current = trailing;
result = 1;
break;
}
} while (first);
return result;
}
/* Search for the bucket immediately preceding *current, in the bucket chain
* starting at first. current, *current and first must not be NULL.
*
* Return:
* 1 *current holds the correct bucket; this is a borrowed reference
* 0 no such bucket exists; *current unaltered
* -1 error; *current unaltered
*/
static int
PreviousBucket(Bucket **current, Bucket *first)
{
Bucket *trailing = NULL; /* first travels; trailing follows it */
int result = 0;
assert(current && *current && first);
if (first == *current)
return 0;
do {
trailing = first;
PER_USE_OR_RETURN(first, -1);
first = first->next;
PER_ALLOW_DEACTIVATION(trailing);
PER_ACCESSED(trailing);
if (first == *current) {
*current = trailing;
result = 1;
break;
}
} while (first);
return result;
}
static Py_ssize_t
BTreeItems_length_or_nonzero(BTreeItems *self, int nonzero)
{
Py_ssize_t r;
Bucket *b, *next;
b = self->firstbucket;
if (b == NULL)
return 0;
r = self->last + 1 - self->first;
if (nonzero && r > 0)
/* Short-circuit if all we care about is nonempty */
return 1;
if (b == self->lastbucket)
return r;
Py_INCREF(b);
PER_USE_OR_RETURN(b, -1);
while ((next = b->next)) {
r += b->len;
if (nonzero && r > 0)
/* Short-circuit if all we care about is nonempty */
break;
if (next == self->lastbucket)
break; /* we already counted the last bucket */
Py_INCREF(next);
PER_UNUSE(b);
Py_DECREF(b);
b = next;
PER_USE_OR_RETURN(b, -1);
}
PER_UNUSE(b);
Py_DECREF(b);
return r >= 0 ? r : 0;
}
/*
** BTreeItems_item
**
** Arguments: self a BTreeItems structure
** i Which item to inspect
**
** Returns: the BTreeItems_item_BTree of self->kind, i
** (ie pulls the ith item out)
*/
static PyObject *
BTreeItems_item(BTreeItems *self, Py_ssize_t i)
{
PyObject *result;
if (BTreeItems_seek(self, i) < 0) return NULL;
PER_USE_OR_RETURN(self->currentbucket, NULL);
result = getBucketEntry(self->currentbucket, self->currentoffset,
self->kind);
PER_UNUSE(self->currentbucket);
return result;
}
/*
** BTreeItems_seek
**
** Find the ith position in the BTreeItems.
**
** Arguments: self The BTree
** i the index to seek to, in 0 .. len(self)-1, or in
** -len(self) .. -1, as for indexing a Python sequence.
**
**
** Returns 0 if successful, -1 on failure to seek (like out-of-bounds).
** Upon successful return, index i is at offset self->currentoffset in bucket
** self->currentbucket.
*/
static int
BTreeItems_seek(BTreeItems *self, Py_ssize_t i)
{
int delta, pseudoindex, currentoffset;
Bucket *b, *currentbucket;
int error;
pseudoindex = self->pseudoindex;
currentoffset = self->currentoffset;
currentbucket = self->currentbucket;
if (currentbucket == NULL) goto no_match;
delta = i - pseudoindex;
while (delta > 0) { /* move right */
int max;
/* Want to move right delta positions; the most we can move right in
* this bucket is currentbucket->len - currentoffset - 1 positions.
*/
PER_USE_OR_RETURN(currentbucket, -1);
max = currentbucket->len - currentoffset - 1;
b = currentbucket->next;
PER_UNUSE(currentbucket);
if (delta <= max) {
currentoffset += delta;
pseudoindex += delta;
if (currentbucket == self->lastbucket
&& currentoffset > self->last) goto no_match;
break;
}
/* Move to start of next bucket. */
if (currentbucket == self->lastbucket || b == NULL) goto no_match;
currentbucket = b;
pseudoindex += max + 1;
delta -= max + 1;
currentoffset = 0;
}
while (delta < 0) { /* move left */
int status;
/* Want to move left -delta positions; the most we can move left in
* this bucket is currentoffset positions.
*/
if ((-delta) <= currentoffset) {
currentoffset += delta;
pseudoindex += delta;
if (currentbucket == self->firstbucket
&& currentoffset < self->first) goto no_match;
break;
}
/* Move to end of previous bucket. */
if (currentbucket == self->firstbucket) goto no_match;
status = PreviousBucket(¤tbucket, self->firstbucket);
if (status == 0)
goto no_match;
else if (status < 0)
return -1;
pseudoindex -= currentoffset + 1;
delta += currentoffset + 1;
PER_USE_OR_RETURN(currentbucket, -1);
currentoffset = currentbucket->len - 1;
PER_UNUSE(currentbucket);
}
assert(pseudoindex == i);
/* Alas, the user may have mutated the bucket since the last time we
* were called, and if they deleted stuff, we may be pointing into
* trash memory now.
*/
PER_USE_OR_RETURN(currentbucket, -1);
error = currentoffset < 0 || currentoffset >= currentbucket->len;
PER_UNUSE(currentbucket);
if (error) {
PyErr_SetString(PyExc_RuntimeError,
"the bucket being iterated changed size");
return -1;
}
Py_INCREF(currentbucket);
Py_DECREF(self->currentbucket);
self->currentbucket = currentbucket;
self->currentoffset = currentoffset;
self->pseudoindex = pseudoindex;
return 0;
no_match:
IndexError(i);
return -1;
}
