forked from 0ad/0ad
84 lines
2.2 KiB
C++
84 lines
2.2 KiB
C++
/* Copyright (c) 2010 Wildfire Games
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* arena allocator (variable-size blocks, no deallocation).
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*/
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#ifndef INCLUDED_ALLOCATORS_ARENA
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#define INCLUDED_ALLOCATORS_ARENA
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#include "lib/allocators/allocator_policies.h"
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namespace Allocators {
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/**
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* allocator design parameters:
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* - O(1) allocation;
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* - variable-size blocks;
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* - support for deallocating all objects;
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* - consecutive allocations are back-to-back;
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* - no extra alignment nor padding.
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**/
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template<class Storage>
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class Arena
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{
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NONCOPYABLE(Arena);
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public:
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Arena(size_t maxSize)
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: storage(maxSize)
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{
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DeallocateAll();
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}
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size_t RemainingBytes() const
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{
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return storage.MaxCapacity() - end;
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}
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void* Allocate(size_t size)
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{
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return (void*)StorageAppend(storage, end, size);
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}
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void DeallocateAll()
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{
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end = 0;
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}
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// @return whether the address lies within the previously allocated range.
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bool Contains(uintptr_t address) const
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{
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return (address - storage.Address()) < end;
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}
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private:
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Storage storage;
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size_t end;
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};
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LIB_API void TestArena();
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} // namespace Allocators
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#endif // #ifndef INCLUDED_ALLOCATORS_ARENA
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