C++如何实现一个简单的内存池_C++内存管理与内存池实现

#include <iostream>
#include <cstdlib>
<p>class FixedMemoryPool {
private:
struct Block {
Block* next;
};</p><pre class='brush:php;toolbar:false;'>char*   pool;         // 内存池起始地址
Block*  free_list;    // 空闲块链表
size_t  block_size;   // 每个块大小（字节）
size_t  num_blocks;   // 块数量

    pool = new char[block_size * num_blocks];
    free_list = nullptr;

    // 将所有块链接成空闲链表
    for (size_t i = 0; i < num_blocks; ++i) {
        Block* block = reinterpret_cast<Block*>(pool + i * block_size);
        block->next = free_list;
        free_list = block;
    }
}

~FixedMemoryPool() {
    delete[] pool;
}

void* allocate() {
    if (!free_list) {
        return nullptr; // 内存池已满
    }
    Block* block = free_list;
    free_list = free_list->next;
    return block;
}

void deallocate(void* ptr) {
    if (ptr) {
        Block* block = static_cast<Block*>(ptr);
        block->next = free_list;
        free_list = block;
    }
}

struct ListNode {
    int data;
    ListNode* next;
    // 禁止默认 operator new/delete 外部调用
    void* operator new(size_t) = delete;
    void operator delete(void*) = delete;
<pre class='brush:php;toolbar:false;'>// 自定义 new 使用内存池
static FixedMemoryPool pool;
static void* operator new(size_t size) {
    return pool.allocate();
}
static void operator delete(void* ptr) {
    pool.deallocate(ptr);
}

ListNode* node = new ListNode{42, nullptr};
delete node; // 实际放回内存池