mirror of https://github.com/jorio/Pomme.git
47 lines
870 B
C++
47 lines
870 B
C++
#pragma once
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namespace Pomme {
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template<typename TObj, typename TId, int MAX>
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class FixedPool
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{
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// fixed size array so that pointers to the elements don't move around in memory
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// (unlike how a vector might move around elements on resize)
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TObj pool[MAX];
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std::vector<TId> freeIDs;
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int inUse, inUsePeak;
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public:
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FixedPool()
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{
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inUse = 0;
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inUsePeak = 0;
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freeIDs.reserve(MAX);
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for (int i = MAX - 1; i >= 0; i--)
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freeIDs.push_back(i);
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}
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TObj* Alloc()
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{
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if (freeIDs.empty())
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throw std::length_error("pool exhausted");
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TId id = freeIDs.back();
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freeIDs.pop_back();
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inUse++;
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if (inUse > inUsePeak)
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inUsePeak = inUse;
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return &pool[id];
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}
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void Dispose(TObj* obj)
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{
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intptr_t id = obj - &pool[0];
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if (id < 0 || id >= MAX)
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throw std::invalid_argument("obj isn't stored in pool");
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inUse--;
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freeIDs.push_back((TId)id);
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}
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};
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}
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