Method alloc

src/core/test/mem_alloc.cpp:44–57

    }

    void* alloc(size_t size) override {
        MGB_LOCK_GUARD(m_mtx);
        if (mgb_unlikely(m_cur_usage + size > m_tot_size)) {
            m_ever_failed = true;
            return nullptr;
        }
        ++m_nr_alloc;
        auto addr = reinterpret_cast<void*>(m_next_addr);
        m_next_addr += size;
        m_cur_usage += size;
        m_peak_usage = std::max(m_peak_usage, m_cur_usage);
        m_addr2size[addr] = size;
        return addr;
    }

    void free(void* ptr) override {
        MGB_LOCK_GUARD(m_mtx);