libcruft-util/alloc/chunked.cpp

109 lines
3.0 KiB
C++

/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2021, Danny Robson <danny@nerdcruft.net>
*/
#include "chunked.hpp"
#include "../debug/warn.hpp"
#include "../log.hpp"
#include "../maths.hpp"
#include "../pointer.hpp"
using cruft::alloc::chunked;
///////////////////////////////////////////////////////////////////////////////
chunked::chunked (std::size_t initial_size)
: chunked (initial_size, DEFAULT_CHUNK_SIZE)
{ ; }
//-----------------------------------------------------------------------------
chunked::chunked (std::size_t initial_size, std::size_t _chunk_size)
: m_chunk (_chunk_size)
{
m_chunk = cruft::max (m_chunk, sizeof (allocation_t));
auto const initial_arenas = cruft::divup (initial_size, m_chunk);
m_data.resize (initial_arenas);
for (auto &i: m_data) {
i.head = i.remain.data = new std::byte[m_chunk];
*i.remain.node = {
.size = m_chunk,
.next = nullptr
};
}
}
//-----------------------------------------------------------------------------
chunked::~chunked () noexcept
{
for (auto &i: m_data)
delete [] i.head;
}
///////////////////////////////////////////////////////////////////////////////
void*
chunked::do_allocate (std::size_t size, std::size_t alignment)
{
// Find a chunk that can service this allocation.
for (auto &i: m_data) {
if (i.remain.node->size < size + alignment)
continue;
auto base = cruft::align::up (i.remain.data, alignment);
std::byte* newbase = base + size;
if (newbase > i.remain.data + i.remain.node->size)
continue;
std::size_t newsize = i.remain.data + i.remain.node->size - newbase;
i.remain.data = newbase;
i.remain.node->size = newsize;
return base;
}
// No chunk was found. We need to allocate a new chunk of at least enough size.
std::size_t allocation_size = cruft::max (size + alignment, m_chunk);
std::unique_ptr<std::byte[]> ptr (new std::byte[allocation_size]);
m_data.push_back (
::cruft::alloc::chunked::arena {
.head = ptr.get (),
.remain = { .data = ptr.get (), },
}
);
m_data.back ().remain.node->size = allocation_size;
m_data.back ().remain.node->next = m_data.back ().remain.node;
ptr.release ();
return do_allocate (size, alignment);
}
//-----------------------------------------------------------------------------
void
chunked::do_deallocate (void *p, std::size_t bytes, std::size_t alignment)
{
(void)p;
(void)bytes;
(void)alignment;
LOG_WARNING ("chunked::do_deallocate is unimplemented");
}
//-----------------------------------------------------------------------------
bool
chunked::do_is_equal (memory_resource const &) const noexcept
{
warn ("chunked::do_is_equal is unimplemented");
return false;
}