127 lines
3.1 KiB
C++
127 lines
3.1 KiB
C++
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2015-2018 Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include "../std.hpp"
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#include "../view.hpp"
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#include "../pointer.hpp"
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#include "../buffer/traits.hpp"
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#include <cstddef>
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#include <iterator>
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namespace cruft::alloc {
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// allocate progressively across a buffer without concern for deallocation.
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// deallocation is a noop; the only way to free allocations is via reset.
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class linear {
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public:
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linear (const linear&) = delete;
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linear& operator= (const linear&) = delete;
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linear (linear&&) noexcept;
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linear& operator= (linear&&) noexcept;
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linear (cruft::view<u08*> _data);
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template <
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typename BufferT,
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typename = std::enable_if_t<
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buffer::is_buffer_v<BufferT>
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>
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>
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linear (BufferT &_buffer)
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: linear (cruft::view (_buffer))
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{ ; }
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cruft::view<u08*>
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allocate (size_t bytes)
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{
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if (m_cursor + bytes > m_end)
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throw std::bad_alloc ();
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auto ptr = m_cursor;
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m_cursor += bytes;
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return { ptr, bytes };
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}
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cruft::view<u08*>
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allocate (size_t bytes, std::size_t alignment)
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{
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auto ptr = cruft::align::up (m_cursor, alignment);
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if (ptr + bytes > m_end)
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throw std::bad_alloc ();
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m_cursor = ptr + bytes;
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return { ptr, bytes };
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}
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void deallocate (void *ptr, std::size_t bytes, std::size_t alignment)
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{
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(void)ptr;
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(void)bytes;
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(void)alignment;
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}
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void deallocate (void *ptr, std::size_t bytes)
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{
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return deallocate (ptr, bytes, alignof (std::max_align_t));
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}
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u08* data (void);
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u08* begin (void);
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u08* end (void);
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u08* cursor (void);
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u08 const* data (void) const;
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u08 const* begin (void) const;
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u08 const* end (void) const;
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u08 const* cursor (void) const;
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size_t offset (const void*) const;
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template <typename ValueT>
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size_t
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offset (ValueT const *ptr) const
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{
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CHECK_MOD (reinterpret_cast<uintptr_t> (ptr), sizeof (ValueT));
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CHECK_MOD (reinterpret_cast<uintptr_t> (data ()), sizeof (ValueT));
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return ptr - cruft::cast::alignment<ValueT const*> (data ());
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}
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template <typename T>
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size_t
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offset (cruft::view<T*> ptr) const
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{
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return offset (ptr.data ());
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}
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void reset (void);
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size_t capacity (void) const;
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size_t used (void) const;
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size_t remain (void) const;
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protected:
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// The begin and end iterators should be constant but that interferes
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// with move operators so we need to leave them mutable.
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u08 *m_begin;
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u08 *m_end;
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u08 *m_cursor;
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};
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}
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