util/memory/mmapalloc.cpp


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#include "alloc.h" 
#include "mmapalloc.h" 
 
#include <util/system/filemap.h> 
#include <util/generic/singleton.h> 
 
namespace { 
    class TMmapAllocator: public IAllocator { 
    public: 
        TBlock Allocate(size_t len) override {
            TMappedAllocation m(len + sizeof(TMappedAllocation)); 
            TMappedAllocation* real = (TMappedAllocation*)m.Data(); 
 
            (new (real) TMappedAllocation(0))->swap(m); 
 
            TBlock ret = {real + 1, len}; 
 
            return ret; 
        } 
 
        void Release(const TBlock& block) override {
            TMappedAllocation tmp(0); 
            TMappedAllocation* real = ((TMappedAllocation*)block.Data) - 1; 
 
            real->swap(tmp); 
            real->~TMappedAllocation(); 
        } 
    }; 
} 
 
IAllocator* MmapAllocator() { 
    return SingletonWithPriority<TMmapAllocator, 0>(); 
}