/* 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;
}
/*
** _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;
}
/* 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;
}