Basic C++ template allocator example

alloc.cpp

// Copyright (c) December 2025 Félix-Olivier Dumas. All rights reserved.
// Licensed under the terms described in the LICENSE file

#include <iostream>

struct Point {
    int x, y;
    Point(int a, int b) : x(a), y(b) {}
    void print() { std::cout << "(" << x << "," << y << ")\n"; }
};

template<typename T>
struct Allocator {
    T* allocate(std::size_t n) {
        return static_cast<T*>(::operator new(sizeof(T) * n));
    }

    void deallocate(T* ptr, std::size_t n) {
        ::operator delete(ptr);
    }

    template<typename... Args>
    void construct(T* ptr, Args&&... args) {
        new (ptr) T(std::forward<Args>(args)...);
    }

    void destroy(T* ptr) {
        ptr->~T();
    }

    std::size_t max_size() const {
        return std::numeric_limits<std::size_t>::max() / sizeof(T);
    }
};