55 lines
1.5 KiB
C++
55 lines
1.5 KiB
C++
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#pragma once
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#include <cinttypes>
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#include "utils/numerics/log2.hpp"
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template <typename PtrT>
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struct PointerPackTraits
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{
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// here is a place to embed something like platform specific things
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// TODO: cover more cases
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constexpr static int free_bits = utils::log2(alignof(PtrT));
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static auto get_ptr(uintptr_t value) { return (PtrT)(value); }
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};
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template <typename PtrT, int IntBits, typename IntT = unsigned,
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typename PtrTraits = PointerPackTraits<PtrT>>
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class PtrInt
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{
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private:
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constexpr static int int_shift = PtrTraits::free_bits - IntBits;
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constexpr static uintptr_t ptr_mask =
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~(uintptr_t)(((intptr_t)1 << PtrTraits::free_bits) - 1);
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constexpr static uintptr_t int_mask =
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(uintptr_t)(((intptr_t)1 << IntBits) - 1);
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uintptr_t value {0};
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public:
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PtrInt(PtrT pointer, IntT integer)
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{
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set_ptr(pointer);
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set_int(integer);
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}
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auto set_ptr(PtrT pointer)
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{
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auto integer = static_cast<uintptr_t>(get_int());
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auto ptr = reinterpret_cast<uintptr_t>(pointer);
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value = (ptr_mask & ptr) | (integer << int_shift);
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}
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auto set_int(IntT integer)
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{
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auto ptr = reinterpret_cast<uintptr_t>(get_ptr());
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auto int_shifted = static_cast<uintptr_t>(integer << int_shift);
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value = (int_mask & int_shifted) | ptr;
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}
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auto get_ptr() const { return PtrTraits::get_ptr(value & ptr_mask); }
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auto get_int() const { return (IntT)((value >> int_shift) & int_mask); }
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};
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