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#pragma once
#include "handle-page.hpp"
#include "compat/assert.hpp"
#include "compat/pretty-function.hpp"
namespace floormat::impl_handle {
template<typename Obj, uint32_t PageSize>
Item<Obj, PageSize>::Item() = default;
template<typename Obj, uint32_t PageSize>
Item<Obj, PageSize>::~Item() noexcept
{}
template<typename Obj, uint32_t PageSize>
void Page<Obj, PageSize>::do_deallocate(Item<Obj, PageSize>& item)
{
item.object.~Obj();
}
template<typename Obj, uint32_t PageSize>
Page<Obj, PageSize>::~Page() noexcept
{
fm_assert(used_count == 0);
}
template<typename Obj, uint32_t PageSize>
Page<Obj, PageSize>::Page(uint32_t start_index):
used_map{ValueInit, PageSize},
start_index{start_index},
used_count{0},
first_free{start_index},
locked{false}
{
fm_assert(start_index + PageSize > start_index);
auto val = start_index;
for (auto i = 0u; i < PageSize; i++)
{
auto& o = storage.data()[i];
o.handle = {val++, 0};
o.next = val;
}
}
template<typename Obj, uint32_t PageSize>
template<typename... Xs>
requires requires (Xs&&... xs) {
Obj{forward<Xs>(xs)...};
}
Item<Obj, PageSize>& Page<Obj, PageSize>::allocate(Xs&&... xs)
{
fm_assert(!locked);
locked = true;
fm_assert(used_count < PageSize);
auto first_freeʹ = first_free - start_index;
fm_debug_assert(first_freeʹ < PageSize);
fm_debug_assert(!used_map[first_freeʹ]);
auto& item = storage[first_freeʹ];
first_free = item.next;
used_count++;
used_map.set(first_freeʹ, true);
new (&item.object) Obj{ forward<Xs>(xs)... };
locked = false;
return item;
}
template<typename Obj, uint32_t PageSize>
void Page<Obj, PageSize>::deallocate(Handle<Obj, PageSize> obj)
{
fm_assert(!locked);
locked = true;
auto index = obj.index - start_index;
fm_debug_assert(index < PageSize);
fm_assert(used_map[index]);
fm_debug_assert(used_count > 0);
fm_debug_assert(first_free != (uint32_t)-1);
auto& item = storage[index];
auto ctr = item.handle.counter++;
if (ctr == (uint32_t)-1) [[unlikely]]
fm_debug("counter overflowed: %s", FM_PRETTY_FUNCTION);
fm_assert(obj.counter == ctr);
item.next = first_free;
first_free = obj.index;
used_count--;
used_map.set(index, false);
do_deallocate(item);
locked = false;
}
template<typename Obj, uint32_t PageSize>
void Page<Obj, PageSize>::deallocate_all()
{
fm_assert(!locked);
locked = true;
for (auto i = 0u; i < PageSize; i++)
if (used_map[i])
do_deallocate(storage[i]);
auto val = start_index;
for (auto i = 0u; i < PageSize; i++)
{
auto& o = storage.data()[i];
bool used = used_map[i];
uint32_t new_ctr = used ? 1 : 0;
o.handle = {val++, o.handle.counter + new_ctr};
o.next = val;
}
first_free = start_index;
used_count = 0;
used_map = BitArray{ValueInit, PageSize};
locked = false;
}
template<typename Obj, uint32_t PageSize>
bool Page<Obj, PageSize>::is_empty()
{
return used_count == 0;
}
template<typename Obj, uint32_t PageSize>
bool Page<Obj, PageSize>::is_full()
{
return used_count == PageSize;
}
template<typename Obj, uint32_t PageSize>
uint32_t Page<Obj, PageSize>::use_count() const
{
return used_count;
}
} // namespace floormat::impl_handle
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