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98 lines
1.5 KiB
98 lines
1.5 KiB
#pragma once
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#include "gp_config.hpp"
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#include "gp/buffer.hpp"
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#include <type_traits>
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#include <gp/algorithm/tmp_manip.hpp>
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namespace gp {
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template<typename page_allocator = int, size_t align = 1>
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class arena {
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page_allocator allocator;
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gp::buffer<char> data;
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size_t last;
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size_t count;
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public:
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arena()
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: last(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(size_t sz)
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: last(0)
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, count(0)
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, data(nullptr,nullptr)
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{
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if constexpr (gp::has_allocator_interface<page_allocator>::value)
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{
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if(sz!=0)
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{
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auto v=allocator.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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}
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arena(char* pos,size_t sz)
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: last(0)
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, count(0)
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, data(pos,pos+sz)
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{}
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void* allocate(size_t sz)
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{
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[[maybe_unused]]
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size_t mod = 0;
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if constexpr (align != 1)
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{
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mod = align - ((intptr_t)data.begin())%align;
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}
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auto ret=data.begin()+last+mod;
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if(data.contains(ret))
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{
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count++;
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last+=sz+mod;
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return &*(ret);
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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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constexpr bool try_reallocate(void*, size_t) {
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return false;
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}
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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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last=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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~arena()
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{
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if constexpr(gp::has_allocator_interface<page_allocator>::value)
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{
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allocator.deallocate(&data[0]);
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}
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}
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};
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}
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