mirror of
https://github.com/matrix-construct/construct
synced 2024-08-31 13:55:19 +02:00
194 lines
5.5 KiB
C++
194 lines
5.5 KiB
C++
/*
|
|
* charybdis: 21st Century IRC++d
|
|
* util.h: Miscellaneous utilities
|
|
*
|
|
* Copyright (C) 2016 Charybdis Development Team
|
|
* Copyright (C) 2016 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
|
|
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
|
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
|
|
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
*/
|
|
|
|
#pragma once
|
|
#define HAVE_IRCD_ALLOCATOR_H
|
|
|
|
namespace ircd {
|
|
|
|
struct allocator
|
|
{
|
|
template<class T = char, size_t = 512> struct fixed;
|
|
};
|
|
|
|
template<class T,
|
|
size_t size>
|
|
struct allocator::fixed
|
|
{
|
|
struct state;
|
|
|
|
using value_type = T;
|
|
using pointer = T *;
|
|
using const_pointer = const T *;
|
|
using reference = T &;
|
|
using const_reference = const T &;
|
|
using size_type = std::size_t;
|
|
using difference_type = std::ptrdiff_t;
|
|
|
|
template<class U> struct rebind
|
|
{
|
|
typedef allocator::fixed<U, size> other;
|
|
};
|
|
|
|
size_type max_size() const { return size; }
|
|
auto address(reference x) const { return &x; }
|
|
auto address(const_reference x) const { return &x; }
|
|
|
|
state *s;
|
|
|
|
pointer allocate(const size_type &n, const const_pointer &hint = nullptr);
|
|
void deallocate(const pointer &p, const size_type &n);
|
|
|
|
fixed(state &) noexcept;
|
|
fixed(fixed &&) = default;
|
|
fixed(const fixed &) = default;
|
|
template<class U, size_t S> fixed(const fixed<U, S> &) noexcept;
|
|
};
|
|
|
|
template<class T,
|
|
size_t size>
|
|
struct allocator::fixed<T, size>::state
|
|
{
|
|
using word_t = unsigned long long;
|
|
|
|
size_t last { 0 };
|
|
std::array<word_t, size / 8> avail { 0 };
|
|
std::array<T, size> buf;
|
|
|
|
static constexpr uint word_bytes { sizeof(word_t) };
|
|
static constexpr uint word_bits { word_bytes * 8 };
|
|
static uint byte(const uint &i) { return i / word_bits; }
|
|
static uint bit(const uint &i) { return i % word_bits; }
|
|
static word_t mask(const uint &pos) { return word_t(1) << bit(pos); }
|
|
|
|
bool test(const uint &pos) const { return avail[byte(pos)] & mask(pos); }
|
|
void bts(const uint &pos) { avail[byte(pos)] |= mask(pos); }
|
|
void btc(const uint &pos) { avail[byte(pos)] &= ~mask(pos); }
|
|
|
|
uint next(const size_t &n) const;
|
|
|
|
allocator::fixed<T, size> operator()() { return { *this }; }
|
|
};
|
|
|
|
template<class... T1,
|
|
class... T2>
|
|
bool operator==(const allocator::fixed<T1...> &, const allocator::fixed<T2...> &);
|
|
|
|
template<class... T1,
|
|
class... T2>
|
|
bool operator!=(const allocator::fixed<T1...> &, const allocator::fixed<T2...> &);
|
|
|
|
} // namespace ircd
|
|
|
|
|
|
template<class T,
|
|
size_t size>
|
|
ircd::allocator::fixed<T, size>::fixed(state &s)
|
|
noexcept
|
|
:s{&s}
|
|
{
|
|
}
|
|
|
|
template<class T,
|
|
size_t size>
|
|
template<class U,
|
|
size_t S>
|
|
ircd::allocator::fixed<T, size>::fixed(const fixed<U, S> &)
|
|
noexcept
|
|
{
|
|
assert(0);
|
|
}
|
|
|
|
template<class T,
|
|
size_t size>
|
|
void
|
|
ircd::allocator::fixed<T, size>::deallocate(const pointer &p,
|
|
const size_type &n)
|
|
{
|
|
const uint pos(p - s->buf.data());
|
|
for(size_t i(0); i < n; ++i)
|
|
s->btc(pos + i);
|
|
}
|
|
|
|
template<class T,
|
|
size_t size>
|
|
typename ircd::allocator::fixed<T, size>::pointer
|
|
ircd::allocator::fixed<T, size>::allocate(const size_type &n,
|
|
const const_pointer &hint)
|
|
{
|
|
const auto next(s->next(n));
|
|
if(unlikely(next >= size)) // No block of n was found anywhere (next is past-the-end)
|
|
throw std::bad_alloc();
|
|
|
|
for(size_t i(0); i < n; ++i)
|
|
s->bts(next + i);
|
|
|
|
s->last = next + n;
|
|
return s->buf.data() + next;
|
|
}
|
|
|
|
template<class T,
|
|
size_t size>
|
|
uint
|
|
ircd::allocator::fixed<T, size>::state::next(const size_t &n)
|
|
const
|
|
{
|
|
uint ret(last), rem(n);
|
|
for(; ret < size && rem; ++ret)
|
|
if(test(ret))
|
|
rem = n;
|
|
else
|
|
--rem;
|
|
|
|
if(likely(!rem))
|
|
return ret - n;
|
|
|
|
for(ret = 0, rem = n; ret < last && rem; ++ret)
|
|
if(test(ret))
|
|
rem = n;
|
|
else
|
|
--rem;
|
|
|
|
if(unlikely(rem)) // The allocator should throw std::bad_alloc if !rem
|
|
return size;
|
|
|
|
return ret - n;
|
|
}
|
|
|
|
template<class... T1,
|
|
class... T2>
|
|
bool
|
|
ircd::operator==(const allocator::fixed<T1...> &a, const allocator::fixed<T2...> &b)
|
|
{
|
|
return &a == &b;
|
|
}
|
|
|
|
template<class... T1,
|
|
class... T2>
|
|
bool
|
|
ircd::operator!=(const allocator::fixed<T1...> &a, const allocator::fixed<T2...> &b)
|
|
{
|
|
return &a != &b;
|
|
}
|