101 lines
2.5 KiB
C++
101 lines
2.5 KiB
C++
/*
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* Copyright (C) 2006-2016 Jacek Sieka, arnetheduck on gmail point com
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifndef ADCHPP_FASTALLOC_H
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#define ADCHPP_FASTALLOC_H
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#include "Mutex.h"
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namespace adchpp {
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#ifdef NDEBUG
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struct FastAllocBase {
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ADCHPP_DLL static FastMutex mtx;
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};
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/**
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* Fast new/delete replacements for constant sized objects, that also give nice
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* reference locality...
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*/
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template<class T>
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struct FastAlloc : public FastAllocBase {
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// Custom new & delete that (hopefully) use the node allocator
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static void* operator new(size_t s) {
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if(s != sizeof(T))
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return ::operator new(s);
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return allocate();
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}
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// Avoid hiding placement new that's needed by the stl containers...
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static void* operator new(size_t, void* m) {
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return m;
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}
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// ...and the warning about missing placement delete...
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static void operator delete(void*, void*) {
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// ? We didn't allocate so...
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}
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static void operator delete(void* m, size_t s) {
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if (s != sizeof(T)) {
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::operator delete(m);
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} else if(m != NULL) {
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deallocate((uint8_t*)m);
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}
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}
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private:
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static void* allocate() {
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FastMutex::Lock l(mtx);
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if(freeList == NULL) {
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grow();
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}
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void* tmp = freeList;
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freeList = *((void**)freeList);
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return tmp;
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}
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static void deallocate(void* p) {
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FastMutex::Lock l(mtx);
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*(void**)p = freeList;
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freeList = p;
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}
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static void* freeList;
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static void grow() {
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dcassert(sizeof(T) >= sizeof(void*));
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// We want to grow by approximately 128kb at a time...
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size_t items = ((128*1024 + sizeof(T) - 1)/sizeof(T));
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freeList = new uint8_t[sizeof(T)*items];
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uint8_t* tmp = (uint8_t*)freeList;
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for(size_t i = 0; i < items - 1; i++) {
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*(void**)tmp = tmp + sizeof(T);
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tmp += sizeof(T);
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}
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*(void**)tmp = NULL;
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}
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};
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template<class T> void* FastAlloc<T>::freeList = 0;
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#else
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template<class T> struct FastAlloc { };
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#endif
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}
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#endif // FASTALLOC_H
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