Pavel Patsey
147 lines
4.3 KiB
Python
147 lines
4.3 KiB
Python
import cProfile
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Node = tuple[int, int, int, int]
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class Cidr4MergerError(Exception):
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pass
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def get_data(input_file):
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with open(input_file, "r") as file:
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data = file.read().splitlines()
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return data
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def cidr4_to_node(cidr4: str) -> Node:
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ip_str, mask_len = cidr4.strip().split("/")
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mask_len = int(mask_len)
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a, b, c, d = list(map(int, ip_str.split(".")))
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ip = a * 256**3 + b * 256**2 + c * 256**1 + d * 256**0
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added_ips_number = 0
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parent_ip = get_parent_ip(ip, mask_len)
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return ip, mask_len, added_ips_number, parent_ip
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def sort_nodes(nodes: list[Node]) -> list[Node]:
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return sorted(nodes, key=lambda x: (x[1], x[0]))
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def get_net_addr(ip: int, mask_len: int) -> int:
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mask = ((1 << mask_len) - 1) << (32 - mask_len)
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net_addr = ip & mask
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return net_addr
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def get_parent_ip(ip: int, mask_len: int) -> int:
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if mask_len == 0:
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raise Cidr4MergerError("The top of the tree has no parent!")
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return get_net_addr(ip, mask_len - 1)
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def have_same_parent(mask_len_a, parent_ip_a, mask_len_b, parent_ip_b) -> bool:
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return mask_len_a == mask_len_b and parent_ip_a == parent_ip_b
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def get_group_with_max_mask_len(nodes: list[Node]) -> list[Node]:
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max_mask_len = max(nodes, key=lambda x: x[1])[1]
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return list(filter(lambda x: x[1] == max_mask_len, nodes))
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def make_parent(a: Node, b: Node | None = None) -> Node:
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ip_a, mask_len_a, added_ips_number_a, parent_ip_a = a
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if b:
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ip_b, mask_len_b, added_ips_b, parent_ip_b = b
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if not have_same_parent(mask_len_a, parent_ip_a, mask_len_b, parent_ip_b):
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raise Cidr4MergerError("Nodes must be neighbors!")
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added_ips_number = added_ips_number_a + added_ips_b
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else:
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added_ips_number = added_ips_number_a + 2 ** (32 - mask_len_a)
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ip = parent_ip_a
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mask_len = mask_len_a - 1
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parent_ip = get_parent_ip(ip, mask_len)
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return ip, mask_len, added_ips_number, parent_ip
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def reduce_nodes(nodes: list[Node]) -> list[Node]:
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group = get_group_with_max_mask_len(nodes)
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neighbours = []
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loners = []
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i = 0
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while i < len(group) - 1:
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a, b = group[i], group[i + 1]
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ip_a, mask_len_a, _, parent_ip_a = a
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ip_b, mask_len_b, _, parent_ip_b = b
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if have_same_parent(mask_len_a, parent_ip_a, mask_len_b, parent_ip_b):
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neighbours.append((a, b))
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i += 2
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else:
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loners.append(a)
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i += 1
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if i == len(group) - 1:
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loners.append(group[i])
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if neighbours:
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zipped = zip(neighbours, map(lambda x: make_parent(x[0], x[1]), neighbours))
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min_zipped = min(zipped, key=lambda x: x[1][2])
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(a, b), parent = min_zipped
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nodes.remove(a)
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nodes.remove(b)
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nodes.append(parent)
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elif loners:
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zipped = zip(loners, map(make_parent, loners))
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min_zipped = min(zipped, key=lambda x: x[1][2])
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a, parent = min_zipped
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nodes.remove(a)
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nodes.append(parent)
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else:
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assert False, "Error"
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return sort_nodes(nodes)
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def merge_nodes(nodes: list[Node], required_len: int) -> list[Node]:
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while len(nodes) > required_len:
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nodes = reduce_nodes(nodes)
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return nodes
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def make_cidr4(ip, mask_len) -> str:
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lst = [str(ip >> (i << 3) & 0xFF) for i in reversed(range(4))]
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ip_str = ".".join(lst)
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return f"{ip_str}/{mask_len}"
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def answer(nodes: list[Node], required_len: int) -> tuple[list[str], int]:
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nodes = sort_nodes(nodes)
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merged_nodes = merge_nodes(nodes, required_len)
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cidr4s = []
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sum_added_ips = 0
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for ip_value, mask_len, added_ips, _ in merged_nodes:
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cidr4s.append(make_cidr4(ip_value, mask_len))
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sum_added_ips += added_ips
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return cidr4s, sum_added_ips
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def main():
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file = "cidr4.txt"
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required_len = 20
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data = get_data(file)
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nodes = list(map(cidr4_to_node, data))
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cidr4s, sum_added_ips = answer(nodes, required_len)
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cidr4s_str = "\n".join(cidr4s)
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print(
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f"Исходный список длины {len(nodes)} сокращен до {len(cidr4s)}\n"
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f"Количество добавленных ip адресов: {sum_added_ips:_}\n"
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f"Список объединенных cidr4:\n"
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f"{cidr4s_str}"
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)
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if __name__ == "__main__":
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cProfile.run("main()")
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