buffer_pool_pointer_swizzling.hpp

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#ifndef __ZERO_BUFFER_POOL_POINTER_SWIZZLING_HPP
#define __ZERO_BUFFER_POOL_POINTER_SWIZZLING_HPP

#include "basics.h"
#include "generic_page.h"
#include "page_evictioner_typedefs.hpp"

namespace zero::buffer_pool {

    class NoSwizzling {
        friend class BufferPool;

    public:
        static constexpr bool usesPointerSwizzling = false;

        static bool isSwizzledPointer(const PageID pid) noexcept {
            return false;
        };

        static PageID makeSwizzledPointer(const bf_idx index) noexcept {
            w_assert0(false);
        };

        static bf_idx makeBufferIndex(const PageID pid) noexcept {
            w_assert0(false);
        };

        static void debugDumpPointer(std::ostream& o, PageID pid);

    private:
        static bf_idx makeBufferIndexForFix(generic_page* parentPage, generic_page*& targetPage, PageID pid) {
            w_assert0(false);
        };
    };

    class SimpleSwizzling {
        friend class BufferPool;

    public:
        static constexpr bool usesPointerSwizzling = true;

        static bool isSwizzledPointer(const PageID pid) noexcept {
            return (pid & swizzledPIDBit) != 0;
        };

        static PageID makeSwizzledPointer(const bf_idx index) noexcept {
            return index | swizzledPIDBit;
        };

        static bf_idx makeBufferIndex(const PageID pid) noexcept {
            return pid & ~swizzledPIDBit;
        };

        static void debugDumpPointer(std::ostream& o, PageID pid);

    private:
        static constexpr PageID swizzledPIDBit = 0b10000000000000000000000000000000;
    };
} // zero::buffer_pool

#endif // __ZERO_BUFFER_POOL_POINTER_SWIZZLING_HPP