operator new

#include <cstdlib>
#include <new>
#include <memory>

static const auto max_align_s = sizeof(std::max_align_t);

void* operator new(size_t size) {
    void* p = std::malloc(size + max_align_s);
    if (p == nullptr) {
        throw std::bad_alloc{};
    }

    char* begin = static_cast<char*>(p) + max_align_s;
    char* end = begin + size;

    std::uninitialized_fill(begin, end, 0x00);

    new (p) int64_t{ size };

    return begin;
}

void operator delete(void* p) {
    if (p == nullptr) {
        return;
    }

    char* c = static_cast<char*>(p) - max_align_s;

    const uint64_t size = *reinterpret_cast<uint64_t*>(c);

    char* begin = static_cast<char*>(p);
    char* end = begin + size;
    std::uninitialized_fill(begin, end, 0xff);

    std::free(c);
}