def zrangebyscore(self,
key,
min_score,
max_score,
withscores=False,
offset=0,
count=float('+inf')):
result = []
num_elems_read = 0
if withscores:
num_elems_per_entry = 2
else:
num_elems_per_entry = 1
score_range = ScoreRange(min_score, max_score)
for db_key in self._db.iterator(
prefix=KEY_CODEC.get_min_zset_score(key), include_value=False):
if len(result) / num_elems_per_entry >= count:
return result
db_score = KEY_CODEC.decode_zset_score(db_key)
if score_range.above_max(db_score):
break
if score_range.check(db_score):
num_elems_read += 1
if len(result) / num_elems_per_entry >= count:
return result
if num_elems_read > offset:
db_value = KEY_CODEC.decode_zset_value(db_key)
result.append(db_value)
if withscores:
result.append(db_score)
return result
def zrange(self, key, start, stop, with_scores):
result = []
zset_length = int(self._db.get(KEY_CODEC.encode_zset(key), '0'))
if stop < 0:
end = zset_length + stop
else:
end = stop
if start < 0:
begin = max(0, zset_length + start)
else:
begin = start
for i, (db_key, _) in enumerate(
self._get_db_iterator(KEY_CODEC.get_min_zset_score(key))):
if i < begin:
continue
if i > end:
break
db_score = KEY_CODEC.decode_zset_score(db_key)
db_value = KEY_CODEC.decode_zset_value(db_key)
result.append(db_value)
if with_scores:
result.append(db_score)
return result
def zrank(self, key, member):
score = self._db.get(KEY_CODEC.encode_zset_value(key, member))
if score is None:
return None
rank = 0
for db_key, _ in self._get_db_iterator(
KEY_CODEC.get_min_zset_score(key)):
db_score = KEY_CODEC.decode_zset_score(db_key)
db_value = KEY_CODEC.decode_zset_value(db_key)
if db_score < float(score):
rank += 1
elif db_score == float(score) and db_value < member:
rank += 1
else:
break
return rank
def zcount(self, key, min_score, max_score):
# TODO: optimize for performance. it's probably possible to create a new entry only for scores
# like:
# <prefix>myzset<score> = number of elements with that score
#
# ZADD myzset 10 a
# <prefix>_myzset_10 = 1 ; one element with score 10
#
# ZADD myzset 10 b
# <prefix>_myzset_10 = 2 ; two elements with score 10
score_range = ScoreRange(min_score, max_score)
count = 0
for db_key, _ in self._get_db_iterator(
KEY_CODEC.get_min_zset_score(key)):
db_score = KEY_CODEC.decode_zset_score(db_key)
if score_range.check(db_score):
count += 1
if score_range.above_max(db_score):
break
return count
def get_key_value_pair(db_key, db_value):
field = KEY_CODEC.decode_zset_value(db_key)
value = KEY_CODEC.decode_zset_score(db_key)
return field, value