import os

from copy import deepcopy

def blacklist_filter_dict(d: dict[str, str], fpl: list[str]) -> dict[str, str]:

"""

Remove all items from `d` prefixed with a string matching a str in `fpl`

Args:

d (dict[str, str]): dictionary to operate on

fpl (list[str]): list of forbidden prefixes used for blacklist

Returns:

dict[str, str]: return modified dictionary

"""

d = deepcopy(d)

for k in list(d.keys()):

for fp in fpl:

if k.startswith(fp):

d.pop(k)

break

return d

def next_path(path_pattern):

"""

Finds the next free path in an sequentially named list of files

e.g. path_pattern = 'file-%s.txt':

file-1.txt

file-2.txt

file-3.txt

Runs in log(n) time where n is the number of existing files in sequence

"""

i = 1

# First do an exponential search

while os.path.exists(path_pattern % i):

i = i * 2

# Result lies somewhere in the interval (i/2..i]

# We call this interval (a..b] and narrow it down until a + 1 = b

a, b = (i // 2, i)

while a + 1 < b:

c = (a + b) // 2 # interval midpoint

a, b = (c, b) if os.path.exists(path_pattern % c) else (a, c)

return path_pattern % b