mirror of https://github.com/axmolengine/axmol.git
113 lines
3.8 KiB
C++
113 lines
3.8 KiB
C++
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#ifndef CC_ALLOCATOR_BASE_H
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#define CC_ALLOCATOR_BASE_H
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/****************************************************************************
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Copyright (c) 2014 Chukong Technologies Inc.
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Author: Justin Graham (https://github.com/mannewalis)
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http://www.cocos2d-x.org
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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****************************************************************************/
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#include "platform/CCPlatformMacros.h"
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#include "base/allocator/CCAllocatorMacros.h"
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#include <string>
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NS_CC_BEGIN
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NS_CC_ALLOCATOR_BEGIN
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// @brief
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// AllocatorBase
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// Provides a base that contains a few methods and definitions that are helpful to all allocation strategies.
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// Also provides a common base that can be used to point to all allocators generically.
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class AllocatorBase
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{
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public:
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typedef void* pointer;
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enum { kDefaultAlignment = 16 };
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// this must be true for SSE instructions to be 16 byte aligned
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// we can now use kDefault alignment as our smallest alloc size
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static_assert(sizeof(uintptr_t) <= kDefaultAlignment, "pointer size must be smaller than default alignment");
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#if CC_ENABLE_ALLOCATOR_DIAGNOSTICS
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AllocatorBase()
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: _next_allocator(nullptr)
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{}
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#endif
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virtual ~AllocatorBase()
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{}
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// @brief
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// Given an address and alignment in bytes, returns an address aligned to the number of bytes
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// For example, if the alignment is 4 which is standard, then the address is divisible evenly by 4.
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CC_ALLOCATOR_INLINE pointer aligned(const pointer address, const size_t alignment = kDefaultAlignment) const
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{
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return (pointer) (((intptr_t)address + (alignment - 1)) & ~(alignment - 1));
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}
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// @brief Calculate the next power of two for a given size.
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// Most blocks requested are already a power of two. For small block alloc
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// this means we cannot add overhead, hence the slightly less performant
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// searching of fixed block pages to determine size if none is specified.
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CC_ALLOCATOR_INLINE size_t nextPow2BlockSize(size_t size) const
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{
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--size;
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size |= size >> 1;
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size |= size >> 2;
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size |= size >> 4;
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size |= size >> 8;
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size |= size >> 16;
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return ++size;
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}
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#if CC_ENABLE_ALLOCATOR_DIAGNOSTICS
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void setTag(const char* tag)
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{
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strncpy(_tag, tag, sizeof(_tag)-1);
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}
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const char* tag() const
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{
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return _tag;
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}
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// cannot use std::string as it allocates memory.
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// for some allocator this tag is set before the new/delete allocator has finished initializing.
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char _tag[1000];
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// @brief return any diagnostic info for this allocator
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virtual std::string diagnostics() const
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{
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return "";
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}
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AllocatorBase* _next_allocator;
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#endif//CC_ENABLE_ALLOCATOR_DIAGNOSTICS
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};
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NS_CC_ALLOCATOR_END
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NS_CC_END
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#endif//CC_ALLOCATOR_BASE_H
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