def _locate_key(self, key, start):
"""
Locate position of the key, it will iterate using `next` field in record
until required key will be find.
:param key: the key to locate
:param start: position to start from
"""
location = start
while True:
self.buckets.seek(location)
data = self.buckets.read(self.entry_line_size)
# todo, maybe partial read there...
try:
l_key, rev, start, size, status, _next = self.entry_struct.unpack(
data)
except struct.error:
raise ElemNotFound("Location '%s' not found" % key)
if l_key == key:
break
else:
if not _next:
# not found
raise ElemNotFound("Location '%s' not found" % key)
else:
location = _next # go to next record
return self.buckets.tell(
) - self.entry_line_size, l_key, rev, start, size, status, _next
def update(self, key, rev, u_start=0, u_size=0, u_status='o'):
start_position = self._calculate_position(key)
self.buckets.seek(start_position)
curr_data = self.buckets.read(self.bucket_line_size)
# test if it's unique or not really unique hash
if curr_data:
location = self.bucket_struct.unpack(curr_data)[0]
else:
raise ElemNotFound("Location '%s' not found" % key)
found_at, _key, _rev, start, size, status, _next = self._locate_key(
key, location)
if u_start == 0:
u_start = start
if u_size == 0:
u_size = size
self.buckets.seek(found_at)
self.buckets.write(self.entry_struct.pack(key,
rev,
u_start,
u_size,
u_status,
_next))
self.flush()
self._find_key.delete(key)
return True