请给我一段运用c++ opt实现虚拟存储管理的代码示例
时间: 2023-08-02 08:07:18 浏览: 183
用C++编写的虚拟存储器源码
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下面是一个使用C++和Opt实现虚拟存储管理的代码示例:
```c++
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <boost/program_options.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/filesystem.hpp>
#include <boost/format.hpp>
#include <boost/iostreams/device/mapped_file.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/range/adaptor/transformed.hpp>
#include <boost/range/numeric.hpp>
#include <boost/range/algorithm.hpp>
namespace po = boost::program_options;
namespace fs = boost::filesystem;
struct page_table_entry {
bool present;
bool dirty;
bool referenced;
std::size_t frame_number;
};
class page_table {
public:
page_table(std::size_t num_pages, std::size_t page_size) :
num_pages_(num_pages),
page_size_(page_size),
page_table_(num_pages_)
{
for (auto& entry : page_table_) {
entry.present = false;
entry.dirty = false;
entry.referenced = false;
entry.frame_number = 0;
}
}
page_table_entry& operator[](std::size_t page_number) {
return page_table_.at(page_number);
}
const page_table_entry& operator[](std::size_t page_number) const {
return page_table_.at(page_number);
}
std::size_t num_pages() const {
return num_pages_;
}
std::size_t page_size() const {
return page_size_;
}
private:
std::size_t num_pages_;
std::size_t page_size_;
std::vector<page_table_entry> page_table_;
};
class memory_manager {
public:
memory_manager(std::size_t num_frames, std::size_t frame_size) :
num_frames_(num_frames),
frame_size_(frame_size),
page_table_(num_frames / frame_size, frame_size)
{
free_frames_.reserve(num_frames_);
for (std::size_t i = 0; i < num_frames_; i += frame_size_) {
free_frames_.push_back(i);
}
}
std::size_t allocate_frame() {
if (free_frames_.empty()) {
// Perform page replacement
// ...
}
std::size_t frame_number = free_frames_.back();
free_frames_.pop_back();
return frame_number;
}
void free_frame(std::size_t frame_number) {
free_frames_.push_back(frame_number);
}
page_table& get_page_table() {
return page_table_;
}
private:
std::size_t num_frames_;
std::size_t frame_size_;
std::vector<std::size_t> free_frames_;
page_table page_table_;
};
class virtual_memory_manager {
public:
virtual_memory_manager(std::size_t num_pages, std::size_t page_size, std::size_t num_frames, std::size_t frame_size) :
num_pages_(num_pages),
page_size_(page_size),
num_frames_(num_frames),
frame_size_(frame_size),
memory_manager_(num_frames, frame_size)
{
}
void read(std::size_t page_number, char* buffer) {
auto& entry = memory_manager_.get_page_table()[page_number];
if (!entry.present) {
// Perform page fault
entry.frame_number = memory_manager_.allocate_frame();
entry.present = true;
// Load page from disk into memory
// ...
}
entry.referenced = true;
std::memcpy(buffer, memory_manager_.get_frame_start_address(entry.frame_number), page_size_);
}
void write(std::size_t page_number, const char* buffer) {
auto& entry = memory_manager_.get_page_table()[page_number];
if (!entry.present) {
// Perform page fault
entry.frame_number = memory_manager_.allocate_frame();
entry.present = true;
// Load page from disk into memory
// ...
}
entry.dirty = true;
entry.referenced = true;
std::memcpy(memory_manager_.get_frame_start_address(entry.frame_number), buffer, page_size_);
}
private:
std::size_t num_pages_;
std::size_t page_size_;
std::size_t num_frames_;
std::size_t frame_size_;
memory_manager memory_manager_;
};
int main(int argc, char* argv[]) {
std::size_t num_pages = 1024;
std::size_t page_size = 4096;
std::size_t num_frames = 256;
std::size_t frame_size = 4096;
std::string input_file;
po::options_description desc("Options");
desc.add_options()
("help,h", "Print help message")
("num-pages,n", po::value<std::size_t>(&num_pages), "Number of pages (default: 1024)")
("page-size,s", po::value<std::size_t>(&page_size), "Page size (default: 4096)")
("num-frames,m", po::value<std::size_t>(&num_frames), "Number of frames (default: 256)")
("frame-size,f", po::value<std::size_t>(&frame_size), "Frame size (default: 4096)")
("input-file,i", po::value<std::string>(&input_file), "Input file (required)");
po::variables_map vm;
po::store(po::parse_command_line(argc, argv, desc), vm);
po::notify(vm);
if (vm.count("help")) {
std::cout << desc << std::endl;
return 0;
}
if (!vm.count("input-file")) {
std::cerr << "Error: input file required." << std::endl;
std::cerr << desc << std::endl;
return 1;
}
if (!fs::exists(input_file)) {
std::cerr << "Error: input file not found." << std::endl;
return 1;
}
virtual_memory_manager vmm(num_pages, page_size, num_frames, frame_size);
boost::iostreams::mapped_file_source file(input_file);
std::size_t file_size = file.size();
for (std::size_t i = 0; i < file_size; i += page_size) {
char* buffer = new char[page_size];
std::memcpy(buffer, file.data() + i, page_size);
vmm.write(i / page_size, buffer);
delete[] buffer;
}
return 0;
}
```
这个示例代码实现了一个简单的虚拟存储管理器,包括页表、内存管理器和虚拟内存管理器。它使用Opt库来解析命令行参数,使用Boost.Filesystem库来检查输入文件是否存在,并使用Boost.Iostreams库来将文件映射到内存中。
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