alloc/chunked: add untested initial implementation

This commit is contained in:
Danny Robson 2021-01-12 14:58:55 +10:00
parent bb7a4e41e6
commit a5c69c5911
2 changed files with 90 additions and 7 deletions

View File

@ -8,7 +8,82 @@
#include "chunked.hpp" #include "chunked.hpp"
#include "../log.hpp"
#include "../maths.hpp"
#include "../pointer.hpp"
using cruft::alloc::chunked; 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 (node_t));
auto const initial_arenas = cruft::divup (initial_size, m_chunk);
m_data.resize (initial_arenas);
for (auto &i: m_data) {
i.data = new std::byte[m_chunk];
*i.node = {
.size = m_chunk,
.next = nullptr
};
}
}
///////////////////////////////////////////////////////////////////////////////
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.node->size < size + alignment)
continue;
auto base = cruft::align::up (i.data, alignment);
std::byte* newbase = base + size;
if (newbase > i.data + i.node->size)
continue;
std::size_t newsize = i.data + i.node->size - newbase;
i.data = newbase;
i.node->size = newsize;
return base;
}
// No chunk was found. We need to allocate a new chunk of at least enough size.
unimplemented ();
}
//-----------------------------------------------------------------------------
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;
}

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@ -14,6 +14,7 @@
#include <cstddef> #include <cstddef>
#endif #endif
#include <memory>
#include <vector> #include <vector>
@ -28,15 +29,18 @@ namespace std::pmr {
[[nodiscard]] void* allocate ( [[nodiscard]] void* allocate (
std::size_t bytes, std::size_t bytes,
std::size_t alignment = alignof (std::max_align_t) std::size_t alignment = alignof (std::max_align_t)
); ) { return do_allocate (bytes, alignment); }
void deallocate( void deallocate(
void* p, void* p,
std::size_t bytes, std::size_t bytes,
std::size_t alignment = alignof(std::max_align_t) std::size_t alignment = alignof(std::max_align_t)
); ) { return do_deallocate (p, bytes, alignment); }
bool is_equal (memory_resource const&) const noexcept; bool is_equal (memory_resource const &rhs) const noexcept
{
return do_is_equal (rhs);
}
private: private:
virtual void *do_allocate (std::size_t bytes, std::size_t alignment) = 0; virtual void *do_allocate (std::size_t bytes, std::size_t alignment) = 0;
@ -77,13 +81,17 @@ namespace cruft::alloc {
bool do_is_equal (memory_resource const&) const noexcept override; bool do_is_equal (memory_resource const&) const noexcept override;
std::size_t m_chunk; std::size_t m_chunk;
struct arena {
std::byte* base; struct node_t {
std::size_t size; std::size_t size;
std::byte* next; node_t* next;
};
union arena {
std::byte *data;
node_t *node;
}; };
std::vector<arena> m_data; std::vector<arena> m_data;
int m_next;
}; };
} }