Initial commit

src/common/bitfield.h

@@ -0,0 +1,121 @@
+#pragma once
+#include <type_traits>
+
+// Disable MSVC warnings that we actually handle
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4800) // warning C4800: 'int': forcing value to bool 'true' or 'false' (performance warning)
+#endif
+
+template<typename BackingDataType, typename DataType, unsigned BitIndex, unsigned BitCount>
+struct BitField
+{
+  constexpr BitField() = default;
+#ifndef _MSC_VER
+  BitField& operator=(const BitField& value) = delete;
+#endif
+
+  constexpr BackingDataType GetMask() const
+  {
+    return ((static_cast<BackingDataType>(~0)) >> (8 * sizeof(BackingDataType) - BitCount)) << BitIndex;
+  }
+
+  operator DataType() const { return GetValue(); }
+
+  BitField& operator=(DataType value)
+  {
+    SetValue(value);
+    return *this;
+  }
+
+  DataType operator++()
+  {
+    DataType value = GetValue() + 1;
+    SetValue(value);
+    return GetValue();
+  }
+
+  DataType operator++(int)
+  {
+    DataType value = GetValue();
+    SetValue(value + 1);
+    return value;
+  }
+
+  DataType operator--()
+  {
+    DataType value = GetValue() - 1;
+    SetValue(value);
+    return GetValue();
+  }
+
+  DataType operator--(int)
+  {
+    DataType value = GetValue();
+    SetValue(value - 1);
+    return value;
+  }
+
+  BitField& operator+=(DataType rhs)
+  {
+    SetValue(GetValue() + rhs);
+    return *this;
+  }
+
+  BitField& operator-=(DataType rhs)
+  {
+    SetValue(GetValue() - rhs);
+    return *this;
+  }
+
+  BitField& operator*=(DataType rhs)
+  {
+    SetValue(GetValue() * rhs);
+    return *this;
+  }
+
+  BitField& operator/=(DataType rhs)
+  {
+    SetValue(GetValue() / rhs);
+    return *this;
+  }
+
+  BitField& operator^=(DataType rhs)
+  {
+    SetValue(GetValue() ^ rhs);
+    return *this;
+  }
+
+  BitField& operator<<=(DataType rhs)
+  {
+    SetValue(GetValue() >> rhs);
+    return *this;
+  }
+
+  BitField& operator>>=(DataType rhs)
+  {
+    SetValue(GetValue() >> rhs);
+    return *this;
+  }
+
+  DataType GetValue() const
+  {
+    // TODO: Handle signed types
+    if (std::is_same<DataType, bool>::value)
+      return static_cast<DataType>(!!((data & GetMask()) >> BitIndex));
+    else
+      return static_cast<DataType>((data & GetMask()) >> BitIndex);
+  }
+
+  void SetValue(DataType value)
+  {
+    data &= ~GetMask();
+    data |= (static_cast<BackingDataType>(value) << BitIndex) & GetMask();
+  }
+
+  BackingDataType data;
+};
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif