From bb269f380aac590ae82200a9533d390d185ab9e8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=9F=D0=B0=D0=B2=D0=B5=D0=BB?= <patsey.pavel@gmail.com>
Date: Wed, 8 Jan 2025 19:21:44 +0300
Subject: [PATCH] add rough_merge_ips function

---
 cidr4_merger.py | 52 ++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 39 insertions(+), 13 deletions(-)

diff --git a/cidr4_merger.py b/cidr4_merger.py
index 0605074..990e333 100644
--- a/cidr4_merger.py
+++ b/cidr4_merger.py
@@ -1,4 +1,4 @@
-import ipaddress
+from copy import deepcopy
 from ipaddress import IPv4Address
 from typing import List, Tuple
 
@@ -20,40 +20,66 @@ def cidr4_to_binary(cidr4: str) -> Tuple[str, int]:
 
 def binary_to_cidr4(binary_ip: str, vlsm: int) -> str:
     int_ip = int(binary_ip, 2)
-    ip_str = str(ipaddress.IPv4Address(int_ip))
+    ip_str = str(IPv4Address(int_ip))
     return f"{ip_str}/{vlsm}"
 
 
 def reduce_bin_ip(bin_ip: str, vlsm: int) -> Tuple[str, int]:
     if vlsm == 0:
-        return bin_ip, vlsm
+        return "0" * 32, vlsm
     new_vlsm = vlsm - 1
     new_bin_ip = bin_ip[:new_vlsm] + "0" * (32 - new_vlsm)
+    if new_bin_ip == "0" * 32:
+        return "0" * 32, 0
     return new_bin_ip, new_vlsm
 
 
+def rough_merge_ips(
+    bin_ips: List[Tuple[str, int]], req_len: int
+) -> List[Tuple[str, int]]:
+    ips = deepcopy(bin_ips)
+    reduction_limit_reached = False
+    while len(ips) > req_len and not reduction_limit_reached:
+        max_vlsm = max(ips, key=lambda x: x[1])[1]
+        ips_to_reduce = []
+        merged_ips = []
+        for ip_vlsm in ips:
+            if ip_vlsm[1] == max_vlsm:
+                ips_to_reduce.append(ip_vlsm)
+            else:
+                merged_ips.append(ip_vlsm)
+        reduced_ips = map(lambda x: reduce_bin_ip(*x), ips_to_reduce)
+        reduced_ips = set(reduced_ips)
+        reduced_ips = filter(lambda x: "1" in x[0], reduced_ips)
+        merged_ips.extend(list(reduced_ips))
+        if len(merged_ips) > req_len:
+            ips = merged_ips
+        else:
+            reduction_limit_reached = True
+    return ips
+
+
 def main():
     file = "cidr4.txt"
     data = get_data(file)
     bin_ips = list(map(cidr4_to_binary, data))
-    for b in bin_ips[:5]:
-        print(b)
+    rough_merged_bin_ips = rough_merge_ips(bin_ips, 20)
+    print(f"{len(rough_merged_bin_ips)=}")
+    sorted_ips = sorted(rough_merged_bin_ips)
+    for ip in sorted_ips:
+        print(ip)
 
 
 if __name__ == "__main__":
     assert cidr4_to_binary("4.78.139.0/24") == ("00000100010011101000101100000000", 24)
     assert binary_to_cidr4("00000100010011101000101100000000", 24) == "4.78.139.0/24"
+
     assert reduce_bin_ip("00000100010011101000101100000000", 24) == (
         "00000100010011101000101000000000",
         23,
     )
-    assert reduce_bin_ip("10000000000000000000000000000000", 1) == (
-        "00000000000000000000000000000000",
-        0,
-    )
-    assert reduce_bin_ip("10000000000000000000000000000000", 0) == (
-        "10000000000000000000000000000000",
-        0,
-    )
+    assert reduce_bin_ip("10000000000000000000000000000000", 1) == ("0" * 32, 0)
+    assert reduce_bin_ip("10000000000000000000000000000000", 0) == ("0" * 32, 0)
+    assert reduce_bin_ip("0" * 32, 0) == ("0" * 32, 0)
 
     main()