112 lines
3.0 KiB
C++
112 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 2015 Danny Robson <danny@nerdcruft.net>
|
|
*/
|
|
|
|
#ifndef CRUFT_UTIL_ALLOC_RAW_LINEAR_HPP
|
|
#define CRUFT_UTIL_ALLOC_RAW_LINEAR_HPP
|
|
|
|
#include "../../view.hpp"
|
|
#include "../../pointer.hpp"
|
|
|
|
#include <cstddef>
|
|
#include <iterator>
|
|
|
|
namespace cruft::alloc::raw {
|
|
// allocate progressively across a buffer without concern for deallocation.
|
|
// deallocation is a noop; the only way to free allocations is via reset.
|
|
class linear {
|
|
public:
|
|
linear (const linear&) = delete;
|
|
linear& operator= (const linear&) = delete;
|
|
|
|
linear (linear&&);
|
|
linear& operator= (linear&&);
|
|
|
|
linear (cruft::view<std::byte*> _data);
|
|
|
|
template <typename T>
|
|
cruft::view<T*>
|
|
allocate (size_t count)
|
|
{
|
|
auto const bytes = count * sizeof (T);
|
|
if (m_cursor + bytes > m_end)
|
|
throw std::bad_alloc ();
|
|
|
|
auto ptr = m_cursor;
|
|
m_cursor += bytes;
|
|
return { cruft::cast::alignment<T*> (ptr), count };
|
|
}
|
|
|
|
|
|
template <typename T>
|
|
cruft::view<T*>
|
|
allocate (size_t count, size_t alignment)
|
|
{
|
|
auto const bytes = count * sizeof (T);
|
|
|
|
auto ptr = cruft::align (m_cursor, alignment);
|
|
if (ptr + bytes > m_end)
|
|
throw std::bad_alloc ();
|
|
|
|
m_cursor = ptr + bytes;
|
|
|
|
return { cruft::cast::alignment<T*> (ptr), count };
|
|
}
|
|
|
|
template <typename T>
|
|
void deallocate (cruft::view<T*> ptr)
|
|
{
|
|
(void)ptr;
|
|
}
|
|
|
|
std::byte* data (void);
|
|
std::byte* begin (void);
|
|
std::byte* end (void);
|
|
std::byte* cursor (void);
|
|
|
|
const std::byte* data (void) const;
|
|
const std::byte* begin (void) const;
|
|
const std::byte* end (void) const;
|
|
const std::byte* cursor (void) const;
|
|
|
|
size_t offset (const void*) const;
|
|
|
|
template <typename ValueT>
|
|
size_t
|
|
offset (ValueT const *ptr) const
|
|
{
|
|
CHECK_MOD (reinterpret_cast<uintptr_t> (ptr), sizeof (ValueT));
|
|
CHECK_MOD (reinterpret_cast<uintptr_t> (data ()), sizeof (ValueT));
|
|
|
|
return ptr - cruft::cast::alignment<ValueT const*> (data ());
|
|
}
|
|
|
|
template <typename T>
|
|
size_t
|
|
offset (cruft::view<T*> ptr) const
|
|
{
|
|
return offset (ptr.data ());
|
|
}
|
|
|
|
void reset (void);
|
|
|
|
size_t capacity (void) const;
|
|
size_t used (void) const;
|
|
size_t remain (void) const;
|
|
|
|
protected:
|
|
// The begin and end iterators should be constant but that interferes
|
|
// with move operators so we need to leave them mutable.
|
|
std::byte *m_begin;
|
|
std::byte *m_end;
|
|
|
|
std::byte *m_cursor;
|
|
};
|
|
}
|
|
|
|
#endif
|