Lucas de Vries
104 lines
1.9 KiB
C++
104 lines
1.9 KiB
C++
#pragma once
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#include <memory>
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namespace memory {
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//A pre-allocated pool of uniformly sized objects
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//Allocated memory is only cleared when all objects in the pool are deleted
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//When all memory is used up, falls back on global operator new/delete
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template<class T, class L>
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class AllocOnlyPool {
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L lock;
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T* pStart, *pNext, *pEnd;
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unsigned allocated;
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public:
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AllocOnlyPool(unsigned count) : allocated(0) {
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pStart = (T*)new unsigned char[count * sizeof(T)];
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pNext = pStart;
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pEnd = pStart + count;
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}
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~AllocOnlyPool() {
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delete[] (unsigned char*)pStart;
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}
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void* alloc() {
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lock.lock();
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void* r;
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if(pNext != pEnd) {
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++allocated;
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r = pNext++;
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lock.release();
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}
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else {
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lock.release();
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r = ::operator new(sizeof(T));
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}
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return r;
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}
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void dealloc(T* p) {
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if(p >= pStart && p < pEnd) {
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lock.lock();
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if(--allocated == 0)
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pNext = pStart;
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lock.release();
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}
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else {
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::operator delete(p);
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}
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}
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};
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//A pre-allocated region for any data types
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//Allocated memory is only cleared when all objects in the pool are deleted
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//When all memory is used up, falls back on global operator new/delete
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template<class Lock>
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class AllocOnlyRegion {
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unsigned char* pStart, *pNext, *pEnd;
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unsigned allocated;
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Lock lock;
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public:
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AllocOnlyRegion(unsigned bytes) : allocated(0) {
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pStart = new unsigned char[bytes];
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pNext = pStart;
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pEnd = pStart + bytes;
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}
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~AllocOnlyRegion() {
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delete[] (unsigned char*)pStart;
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}
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void* alloc(size_t size) {
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lock.lock();
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if(size < (size_t)(pEnd - pNext)) {
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++allocated;
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auto pCopy = pNext;
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pNext += size;
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lock.release();
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return pCopy;
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}
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else {
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lock.release();
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return ::operator new(size);
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}
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}
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void dealloc(void* p) {
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if(p >= pStart && p < pEnd) {
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lock.lock();
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if(--allocated == 0)
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pNext = pStart;
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lock.release();
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}
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else {
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::operator delete(p);
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}
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}
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};
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};
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