Initial commit

arm9/source/core/BitVector.h

@@ -0,0 +1,53 @@
+#pragma once
+#include <array>
+
+template <u32 Length>
+class BitVector
+{
+public:
+    BitVector()
+    {
+        Clear();
+    }
+
+    u32 Get(u32 idx) const
+    {
+        return (_flags[idx >> 5] >> (idx & 0x1F)) & 1;
+    }
+
+    void Set(u32 idx, u32 value)
+    {
+        u32 f = _flags[idx >> 5];
+        if (value)
+            f |= 1 << (idx & 0x1F);
+        else
+            f &= ~(1 << (idx & 0x1F));
+        _flags[idx >> 5] = f;
+    }
+
+    void Clear()
+    {
+        _flags.fill(0);
+    }
+
+    [[gnu::noinline]]
+    constexpr int FindFirstZero()
+    {
+        u32 globalBitNr = 0;
+        for (const u32 bits : _flags)
+        {
+            if (bits == ~0u)
+            {
+                globalBitNr += 32;
+                continue;
+            }
+            u32 invBits = ~bits;
+            globalBitNr += 31 - __builtin_clz(-invBits & invBits);
+            return globalBitNr >= Length ? -1 : globalBitNr;
+        }
+        return -1;
+    }
+
+private:
+    std::array<u32, (Length + 31) / 32> _flags;
+};