67 lines
1.7 KiB
C++
67 lines
1.7 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 2021, Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include <memory_resource>
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#include <memory>
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#include <vector>
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///////////////////////////////////////////////////////////////////////////////
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namespace cruft::alloc {
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/// An unbounded contiguous allocator that operates on chunks, similar to
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/// a deque.
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///
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/// It's useful as a means to keep unknown sized allocations in roughly
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/// the same memory region.
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///
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/// This class models std::pmr::memory_resource.
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class chunked : public std::pmr::memory_resource {
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public:
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static constexpr std::size_t DEFAULT_CHUNK_SIZE = 4096;
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explicit chunked (std::size_t initial_size);
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chunked (std::size_t initial_size, std::size_t chunk_size);
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~chunked () noexcept;
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private:
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void* do_allocate (
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std::size_t bytes,
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std::size_t alignment = alignof (std::max_align_t)
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) override;
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void do_deallocate (
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void *p,
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std::size_t bytes,
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std::size_t alignment = alignof (std::max_align_t)
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) override;
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bool do_is_equal (memory_resource const&) const noexcept override;
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std::size_t m_chunk;
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struct allocation_t {
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std::size_t size;
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allocation_t* next;
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};
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union node {
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std::byte *data;
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allocation_t *node;
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};
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struct arena {
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std::byte *head;
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node remain;
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};
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std::vector<arena> m_data;
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};
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} |