继续完善这个代码 我编写了一个cache模拟器，其中功能满足可以选择三种映射方式、命中处理、两种替换方式（Random和LRU），我的输入是cache的大小、块大小、选择何种映射方式、选择何种替换方式、内存大小、现在我要把形如： L 0x7ef00 S 0x7ef00 这样的内存地址访问序列文件为输入，并统计hit/miss情况，请用c++帮我实现

好的，下面是一个简单的实现：

#include <iostream>
#include <fstream>
#include <vector>
#include <unordered_map>
#include <queue>
#include <cstdlib>
#include <ctime>
using namespace std;

// 定义缓存块结构体
struct CacheBlock {
    bool valid; // 是否有效
    bool dirty; // 是否脏
    int tag; // 标记位
    int last_used; // 最后使用时间
};

// 定义缓存结构体
struct Cache {
    int size; // 大小
    int block_size; // 块大小
    int num_blocks; // 块数
    int num_sets; // 组数
    int set_index_bits; // 组索引位数
    int block_offset_bits; // 块偏移位数
    vector<vector<CacheBlock>> blocks; // 缓存块
    unordered_map<int, int> tag_to_set; // 标记位到组索引的映射
    queue<int> lru_queue; // LRU队列，存储最近使用时间
};

// 初始化缓存
void init_cache(Cache& cache, int size, int block_size, string mapping_method) {
    cache.size = size;
    cache.block_size = block_size;
    cache.num_blocks = size / block_size;
    if (mapping_method == "direct") {
        cache.num_sets = cache.num_blocks;
        cache.set_index_bits = 0;
    } else if (mapping_method == "assoc") {
        cache.num_sets = 1;
        cache.set_index_bits = 0;
    } else if (mapping_method.substr(0, 6) == "assoc:") {
        cache.num_sets = stoi(mapping_method.substr(6));
        cache.set_index_bits = 0;
    } else {
        int n = stoi(mapping_method.substr(0, mapping_method.find(":")));
        cache.num_sets = cache.num_blocks / n;
        cache.set_index_bits = log2(cache.num_sets);
    }
    cache.block_offset_bits = log2(block_size);
    cache.blocks = vector<vector<CacheBlock>>(cache.num_sets, vector<CacheBlock>(n, {false, false, 0, 0}));
}

// 获取内存地址的块偏移
int get_block_offset(int address, int block_offset_bits) {
    return address & ((1 << block_offset_bits) - 1);
}

// 获取内存地址的标记位
int get_tag(int address, int block_offset_bits, int set_index_bits) {
    return address >> (block_offset_bits + set_index_bits);
}

// 获取内存地址的组索引
int get_set_index(int address, int block_offset_bits, int set_index_bits) {
    return (address >> block_offset_bits) & ((1 << set_index_bits) - 1);
}

// 判断是否命中
bool is_hit(Cache& cache, int address) {
    int block_offset = get_block_offset(address, cache.block_offset_bits);
    int set_index = get_set_index(address, cache.block_offset_bits, cache.set_index_bits);
    int tag = get_tag(address, cache.block_offset_bits, cache.set_index_bits);
    for (int i = 0; i < cache.blocks[set_index].size(); i++) {
        if (cache.blocks[set_index][i].valid && cache.blocks[set_index][i].tag == tag) {
            cache.blocks[set_index][i].last_used = time(nullptr);
            return true;
        }
    }
    return false;
}

// 添加缓存块
void add_block(Cache& cache, int address, bool is_write) {
    int block_offset = get_block_offset(address, cache.block_offset_bits);
    int set_index = get_set_index(address, cache.block_offset_bits, cache.set_index_bits);
    int tag = get_tag(address, cache.block_offset_bits, cache.set_index_bits);
    CacheBlock block = {true, is_write, tag, time(nullptr)};
    if (cache.blocks[set_index].size() < cache.num_sets) {
        cache.blocks[set_index].push_back(block);
        cache.tag_to_set[tag] = set_index;
    } else {
        int victim_index;
        if (cache.replacement_method == "random") {
            victim_index = rand() % cache.blocks[set_index].size();
        } else if (cache.replacement_method == "LRU") {
            while (!cache.lru_queue.empty() && !cache.blocks[set_index][cache.lru_queue.front()].valid) {
                cache.lru_queue.pop();
            }
            victim_index = cache.lru_queue.front();
            cache.lru_queue.pop();
        }
        CacheBlock& victim_block = cache.blocks[set_index][victim_index];
        if (victim_block.dirty) {
            // 如果脏，需要写回到内存
            int victim_address = (victim_block.tag << (cache.block_offset_bits + cache.set_index_bits)) | (set_index << cache.block_offset_bits);
            // write_back(victim_address);
        }
        victim_block.valid = true;
        victim_block.dirty = is_write;
        victim_block.tag = tag;
        victim_block.last_used = time(nullptr);
        cache.tag_to_set[tag] = set_index;
    }
}

// 访问内存地址
void access_memory(Cache& cache, int address, char operation) {
    bool is_write = operation == 'S';
    if (is_hit(cache, address)) {
        cache.num_hits++;
    } else {
        cache.num_misses++;
        add_block(cache, address, is_write);
    }
}

// 读取内存地址序列文件
void read_address_sequence(Cache& cache, string file_path) {
    ifstream fin(file_path);
    char operation;
    int address;
    while (fin >> operation >> hex >> address) {
        access_memory(cache, address, operation);
    }
    fin.close();
}

int main() {
    // 读取输入
    int cache_size, block_size, memory_size;
    string mapping_method, replacement_method, file_path;
    cin >> cache_size >> block_size >> mapping_method >> replacement_method >> memory_size >> file_path;

    // 初始化缓存
    Cache cache;
    cache.replacement_method = replacement_method;
    init_cache(cache, cache_size, block_size, mapping_method);

    // 读取内存地址序列文件
    read_address_sequence(cache, file_path);

    // 输出结果
    cout << "Hits: " << cache.num_hits << endl;
    cout << "Misses: " << cache.num_misses << endl;

    return 0;
}

需要注意的是，该代码中的 `access_memory` 函数只是简单地判断是否命中并添加缓存块，实际的读写操作需要根据情况进行实现。