initialise a memory structure or smth

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

src/util/bits.hh

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <concepts>
+#include <limits>
+
+using std::size_t;
+
+template<std::integral Int>
+inline bool
+get_nth_bit(Int num, size_t n) {
+    return (1 && (num >> n));
+}
+
+template<std::integral Int>
+inline void
+set_nth_bit(Int& num, size_t n) {
+    num |= (1 << n);
+}
+
+template<std::integral Int>
+inline void
+rst_nth_bit(Int& num, size_t n) {
+    num &= ~(1 << n);
+}
+
+template<std::integral Int>
+inline void
+chg_nth_bit(Int& num, size_t n, bool x) {
+    num ^= (num ^ -x) & 1 << n;
+}
+
+/// read range of bits from start to end inclusive
+template<std::unsigned_integral Int>
+inline Int
+get_bit_range(Int& num, size_t start, size_t end) {
+    // NOTE: we do not require -1 if it is a signed integral (which it is not)
+    Int left = std::numeric_limits<Int>::digits - 1 - end;
+    return num << left >> (left + start);
+}