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110 lines
2.0 KiB
110 lines
2.0 KiB
#pragma once
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#include "gp_config.hpp"
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#include "gp/algorithm/min_max.hpp"
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#include "gp/algorithm/tmp_manip.hpp"
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#include "gp/buffer.hpp"
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#include "gp/math/integer_math.hpp"
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#include "gp/allocator/allocator.hpp"
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#include <type_traits>
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namespace gp {
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class arena : public allocator {
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gp::optional<gp::reference_wrapper<allocator>> allocator_v;
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size_t next;
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size_t count;
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gp::buffer<char> data;
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public:
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arena()
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: next(0)
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, count(0)
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, data(gp::buffer<char>(nullptr,nullptr))
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{}
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arena(allocator& allocator_p, size_t sz)
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: allocator_v(allocator_p)
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, next(0)
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, count(0)
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, data(nullptr,nullptr)
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{
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if(sz != 0)
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{
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auto v = allocator_v.value().get().allocate(sz);
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if(v != nullptr)
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{
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data=gp::buffer<char>(reinterpret_cast<char*>(v),reinterpret_cast<char*>(v)+sz);
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}
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}
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}
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arena(char* pos, size_t sz)
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: next(0)
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, count(0)
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, data(pos,pos+sz)
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{}
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void reset() {
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next = count = 0;
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}
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virtual void* allocate(size_t sz)
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{
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size_t align = gp::min((1 << gp::math::log2(sz)), 16);
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size_t padding = align - (reinterpret_cast<uintptr_t>(data.begin().data + next)) % align;
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auto ret=data.begin()+padding+next;
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if(data.contains(ret))
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{
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count++;
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next+=padding+sz;
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return ret.data;
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}
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else
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{
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return nullptr;
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}
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}
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/**
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* @return false whatever happens
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*/
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virtual bool try_reallocate(void*, size_t) {
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return false;
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}
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/**
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* @brief Deallocates the memory if every deallocated block as been deallocated, else marks one deallocation
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*
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* @param ptr the memory to deallocate
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* @return true if either a deallocation or block release happened
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* @return false if the pointer was not within the managed area
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*/
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virtual bool deallocate(void* ptr)
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{
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if(data.contains((char*)ptr))
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{
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count--;
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if(count==0)
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{
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for(auto& i : data)
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{
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i=0;
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}
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next=0;
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}
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return true;
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}
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return false;
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}
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virtual ~arena()
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{
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if(allocator_v.has_value())
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{
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allocator_v.value().get().deallocate(&data[0]);
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}
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}
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};
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}
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