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ircd::util: Add a constexpr bitset.
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143
include/ircd/util/bitset.h
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143
include/ircd/util/bitset.h
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// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2022 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_UTIL_BITSET_H
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namespace ircd {
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inline namespace util
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{
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template<size_t>
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struct bitset;
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}}
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template<size_t N>
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struct ircd::util::bitset
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{
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using word = uint8_t;
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static constexpr size_t word_bits
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{
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sizeof(word) * 8
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};
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static constexpr size_t words
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{
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N / word_bits?: 1
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};
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private:
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word buf[words] {0};
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public:
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constexpr size_t size() const
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{
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return N;
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}
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constexpr bool test(const size_t pos) const;
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constexpr size_t count() const;
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constexpr void reset(const size_t pos);
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constexpr void reset();
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constexpr void set(const size_t pos, const bool val = true);
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constexpr void set();
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constexpr void flip(const size_t pos);
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constexpr void flip();
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constexpr bitset(const uint128_t val);
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constexpr bitset() = default;
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};
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template<size_t N>
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constexpr
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ircd::util::bitset<N>::bitset(const uint128_t val)
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{
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const auto bits
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{
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std::min(sizeof(buf) * 8, sizeof(val) * 8)
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};
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size_t i{0};
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for(; i < bits; ++i)
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{
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const decltype(val) one{1};
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set(i, val & (one << i));
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}
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for(; i < size(); ++i)
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set(i, false);
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}
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template<size_t N>
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constexpr void
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ircd::util::bitset<N>::flip()
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{
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for(size_t i(0); i < words; ++i)
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buf[i] =~ buf[i];
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}
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template<size_t N>
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constexpr void
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ircd::util::bitset<N>::flip(const size_t pos)
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{
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buf[pos / 8] ^= word(1) << (pos % 8);
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}
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template<size_t N>
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constexpr void
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ircd::util::bitset<N>::set()
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{
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for(size_t i(0); i < words; ++i)
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buf[i] = ~word{0};
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}
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template<size_t N>
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constexpr void
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ircd::util::bitset<N>::set(const size_t pos,
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const bool val)
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{
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buf[pos / 8] |= word(val) << (pos % 8);
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}
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template<size_t N>
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constexpr void
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ircd::util::bitset<N>::reset()
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{
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for(size_t i(0); i < words; ++i)
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buf[i] = 0;
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}
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template<size_t N>
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constexpr void
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ircd::util::bitset<N>::reset(const size_t pos)
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{
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buf[pos / 8] &= ~(word(1) << (pos % 8));
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}
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template<size_t N>
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constexpr size_t
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ircd::util::bitset<N>::count()
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const
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{
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size_t ret(0);
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for(size_t i(0); i < words; ++i)
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ret += std::popcount(buf[i]);
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return ret;
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}
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template<size_t N>
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constexpr bool
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ircd::util::bitset<N>::test(const size_t pos)
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const
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{
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return buf[pos / 8] & (word(1) << (pos % 8));
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}
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@ -65,6 +65,7 @@ namespace ircd
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#include "maybe.h"
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#include "all.h"
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#include "compare_exchange.h"
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#include "bitset.h"
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// Unsorted section
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namespace ircd {
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