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construct/include/ircd/util/bitset.h

167 lines
3 KiB
C++

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