initial commit

1 files changed, 48 insertions, 0 deletions

diff --git a/include/util/bitset.hpp b/include/util/bitset.hpp
new file mode 100644
index 0000000..8798a4a
--- /dev/null
+++ b/include/util/bitset.hpp
@@ -0,0 +1,48 @@
+#pragma once
+
+#include <array>
+#include <cassert>
+#include <cstdint>
+
+constexpr int bits_ceil(int bits) {
+    return bits / 8 + (bits % 8 > 0 ? 1 : 0);
+}
+
+template <unsigned int flags, auto size = bits_ceil(flags)>
+struct bitset : std::array<std::uint8_t, size> {
+    using array_type = std::array<std::uint8_t, size>;
+
+private:
+    struct bit_ref {
+        bitset<flags> &a;
+        int     referenced_byte;
+        uint8_t referenced_bit_mask;
+        
+        bool operator=(bool b) {
+            if (b)
+                a.at(referenced_byte) |= referenced_bit_mask;
+            else 
+                a.at(referenced_byte) &= ~referenced_bit_mask;
+            return b;        
+        }
+
+        constexpr operator bool() const {
+            return (a.at(referenced_byte) & referenced_bit_mask) > 0;
+        }
+    };
+
+public:
+    template<class T>
+    constexpr bool operator [](T idx) const {
+        unsigned int i = (unsigned int)(idx);
+        assert(i < flags);
+        return (array_type::at(i/8) & (1 << (i%8))) > 0;
+    }
+
+    template<class T>
+    bit_ref operator[](T idx)  {
+        unsigned int i = (unsigned int)(idx);
+        assert(i < flags);
+        return bit_ref(*this, i/8, (1 << (i%8)));
+    }
+};
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