aligned allocator

aligned_allocator.h

#pragma once

#include<memory>

template<int alignment>
struct aligned_allocator
{
    static_assert((alignment&(alignment - 1)) == 0, "alignment must be power of 2.");

    void* allocate(size_t size) {
        size += alignment;
        uint8_t* mem = (uint8_t*)std::malloc(size);
         
        uint8_t* aligned = (uint8_t*) ((size_t) (mem + alignment) & (~(size_t)(alignment - 1)));
        
        auto offset = aligned - mem;

        aligned[-1] = (uint8_t)offset;
        
        return aligned;
    }

    void free(void* addr) {
        uint8_t* aligned = (uint8_t*)addr;
        
        auto offset = aligned[-1];

        std::free(aligned - offset);
    }
};