elexis
43137fef3f
Differential Revision: https://code.wildfiregames.com/D716
Refs 09e974e1cb
Reviewed By: bb
Change in agreement with leper.
This was SVN commit r19899.
65 lines
2.5 KiB
C
65 lines
2.5 KiB
C
/* Copyright (C) 2011 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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#ifndef INCLUDED_ALLOCATORS_FREELIST
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#define INCLUDED_ALLOCATORS_FREELIST
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// "freelist" is a pointer to the first unused element or a sentinel.
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// their memory holds a pointer to the previous element in the freelist
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// (or its own address in the case of sentinels to avoid branches)
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//
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// rationale for the function-based interface: a class encapsulating the
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// freelist pointer would force each header to include this header,
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// whereas this approach only requires a void* pointer and calling
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// mem_freelist_Sentinel from the implementation.
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//
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// these functions are inlined because allocation is sometimes time-critical.
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// @return the address of a sentinel element, suitable for initializing
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// a freelist pointer. subsequent mem_freelist_Detach on that freelist
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// will return 0.
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LIB_API void* mem_freelist_Sentinel();
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static inline void mem_freelist_AddToFront(void*& freelist, void* el)
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{
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ASSERT(freelist != 0);
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ASSERT(el != 0);
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memcpy(el, &freelist, sizeof(void*));
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freelist = el;
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}
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// @return 0 if the freelist is empty, else a pointer that had
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// previously been passed to mem_freelist_AddToFront.
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static inline void* mem_freelist_Detach(void*& freelist)
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{
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ASSERT(freelist != 0);
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void* prev_el;
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memcpy(&prev_el, freelist, sizeof(void*));
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void* el = (freelist == prev_el)? 0 : freelist;
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freelist = prev_el;
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return el;
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}
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#endif // #ifndef INCLUDED_ALLOCATORS_FREELIST
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