35 lines
776 B
C++
35 lines
776 B
C++
// This file is part of the mcl project.
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// Copyright (c) 2022 merryhime
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// SPDX-License-Identifier: MIT
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#pragma once
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#include "mcl/bitsizeof.hpp"
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#include "mcl/stdint.hpp"
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namespace mcl::detail {
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/// if MSB is 0, this is a full slot. remaining 7 bits is a partial hash of the key.
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/// if MSB is 1, this is a non-full slot.
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enum class meta_byte : u8 {
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empty = 0xff,
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tombstone = 0x80,
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end_sentinel = 0x88,
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};
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inline bool is_full(meta_byte mb)
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{
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return (static_cast<u8>(mb) & 0x80) == 0;
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}
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inline meta_byte meta_byte_from_hash(size_t hash)
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{
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return static_cast<meta_byte>(hash >> (bitsizeof<size_t> - 7));
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}
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inline size_t group_index_from_hash(size_t hash, size_t group_index_mask)
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{
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return hash & group_index_mask;
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}
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} // namespace mcl::detail
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