init

lib/internal.nix

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+{ lib }:
+let
+  inherit (builtins) elemAt genList;
+  inherit (lib) mod;
+in
+rec {
+  # Power of 2 calculation
+  # pow2 n returns 2^n
+  pow2 =
+    n:
+    if n == 0 then
+      1
+    else if n == 1 then
+      2
+    else
+      let
+        half = n / 2;
+        halfPow = pow2 half;
+      in
+      halfPow * halfPow * (if mod n 2 == 1 then 2 else 1);
+
+  # Convert list of 4 octets to 32-bit integer
+  # [192 168 1 1] -> 3232235777
+  octetsToInt =
+    octets:
+    let
+      a = elemAt octets 0;
+      b = elemAt octets 1;
+      c = elemAt octets 2;
+      d = elemAt octets 3;
+    in
+    a * 16777216 + b * 65536 + c * 256 + d;
+
+  # Convert 32-bit integer to list of 4 octets
+  # 3232235777 -> [192 168 1 1]
+  intToOctets =
+    ip:
+    let
+      a = ip / 16777216;
+      remainder1 = mod ip 16777216;
+      b = remainder1 / 65536;
+      remainder2 = mod remainder1 65536;
+      c = remainder2 / 256;
+      d = mod remainder2 256;
+    in
+    [
+      a
+      b
+      c
+      d
+    ];
+
+  # Generate a list of integers from start to end (inclusive)
+  # More efficient than recursive approach for large ranges
+  intRange = start: end: if end < start then [ ] else genList (i: start + i) (end - start + 1);
+}