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C++文件系统操作4 - 跨平台实现获取文件|文件夹的大小

CPP基础工具库

发布：2024-07-24 22:40:00

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1. 关键词

C++ 文件系统操作 获取文件的大小 获取文件夹的大小 跨平台

2. fileutil.h

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#pragma once

#include <string>
#include <cstdio>
#include <cstdint>
#include "filetype.h"
#include "filepath.h"

namespace cutl
{

    /**
     * @brief The file guard class to manage the FILE pointer automatically.
     * file_guard object can close the FILE pointer automatically when his scope is exit.
     */
    class file_guard
    {
    public:
        /**
         * @brief Construct a new file guard object
         *
         * @param file the pointer of the FILE object
         */
        explicit file_guard(FILE *file);

        /**
         * @brief Destroy the file guard object
         *
         */
        ~file_guard();

        /**
         * @brief Get the FILE pointer.
         *
         * @return FILE*
         */
        FILE *getfd() const;

    private:
        FILE *file_;
    };

    /**
     * @brief Get the size of a file.
     *
     * @param filepath the filepath of the file to be checked
     *
     * @param link_target whether to get the size of the file pointed by symbolic link, default is false.
     * If link_target is true, the function will get the size of the file pointed by symbolic link, not the symbolic link itself.
     *
     * @note link_target parameter only works on Unix-like systems, not support on Windows.
     *
     * @return file size in bytes
     */
    uint64_t filesize(const filepath &filepath, bool link_target = false);

    /**
     * @brief Get the size of a directory, include all files and subdirectories.
     *
     * @param dirpath the filepath of the directory to be checked
     * @return the total size of the directory in bytes
     */
    uint64_t dirsize(const filepath &dirpath);

} // namespace cutl

3. fileutil.cpp

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#include <cstdio>
#include <map>
#include <iostream>
#include <cstring>
#include <sys/stat.h>
#include "fileutil.h"
#include "inner/logger.h"
#include "inner/filesystem.h"
#include "strutil.h"

namespace cutl
{
    file_guard::file_guard(FILE *file)
        : file_(file)
    {
    }

    file_guard::~file_guard()
    {
        if (file_)
        {
            // CUTL_DEBUG("close file");
            int ret = fclose(file_);
            if (ret != 0)
            {
                CUTL_ERROR("fail to close file, ret" + std::to_string(ret));
            }
            file_ = nullptr;
        }
        // ROBOLOG_DCHECK(file_ == nullptr);
    }

    FILE *file_guard::getfd() const
    {
        return file_;
    }

    uint64_t filesize(const filepath &filepath, bool link_target)
    {
        if (!filepath.exists())
        {
            CUTL_ERROR("filepath does not exist: " + filepath.str());
            return 0;
        }

        return get_filesize(filepath.str(), link_target);
    }

    uint64_t dirsize(const filepath &dirpath)
    {
        return get_dirsize(dirpath.str());
    }

4. filesystem_win.h

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#include <vector>
#include <string>

#pragma once

namespace cutl
{
    // get file size in bytes
    uint64_t get_filesize(const std::string &filepath, bool link_target);
    // get directory size in bytes
    uint64_t get_dirsize(const std::string &dirpath);
} // namespace cutl

5. filesystem_win.cpp

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#if defined(_WIN32) || defined(__WIN32__)

#include <io.h>
#include <direct.h>
#include <Windows.h>
#include <stdlib.h>
#include "strutil.h"
#include "filesystem.h"
#include "logger.h"

namespace cutl
{
    // get file size in bytes
    uint64_t get_filesize(const std::string &filepath, bool link_target)
    {
        struct stat statbuf;
        int ret = stat(filepath.c_str(), &statbuf);
        if (ret != 0)
        {
            CUTL_ERROR("stat " + filepath + " error, ret:" + std::to_string(ret));
            return 0;
        }

        return static_cast<uint64_t>(statbuf.st_size);
    }

    // get directory size in bytes
    uint64_t get_dirsize(const std::string &dirpath)
    {
        uint64_t totalSize = 0;

        auto findpath = dirpath + win_separator + "*.*";
        WIN32_FIND_DATAA data = {0};
        HANDLE hFind = FindFirstFileA(findpath.c_str(), &data);
        bool unicode = true;
        if (hFind == INVALID_HANDLE_VALUE || hFind == NULL)
        {
            CUTL_ERROR("FindFirstFileA failed for " + findpath + ", errCode: " + std::to_string(GetLastError()));
            return totalSize;
        }

        do
        {
            auto dwAttrs = data.dwFileAttributes;
            auto filename = std::string(data.cFileName);
            if (is_special_dir(filename))
            {
                // “..”和“.”不做处理
                continue;
            }
            std::string filepath = dirpath + win_separator + filename;
            if ((dwAttrs & FILE_ATTRIBUTE_DIRECTORY))
            {
                // directory
                auto subdir_size = get_dirsize(filepath);
                totalSize += subdir_size;
            }
            else
            {
                // file
                auto subfile_size = get_filesize(filepath, false);
                totalSize += subfile_size;
            }
        } while (FindNextFileA(hFind, &data));
        // 关闭句柄
        FindClose(hFind);

        return totalSize;
    }
} // namespace cutl

#endif // defined(_WIN32) || defined(__WIN32__)

6. filesystem_unix.cpp

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#if defined(_WIN32) || defined(__WIN32__)
// do nothing
#else

#include <unistd.h>
#include <sys/stat.h>
#include <dirent.h>
#include <stack>
#include <cstring>
#include <utime.h>
#include <stdlib.h>
#include <sys/time.h>
#include "filesystem.h"
#include "inner/logger.h"

namespace cutl
{
    uint64_t get_filesize(const std::string &filepath, bool link_target)
    {
        struct stat statbuf;
        int ret = 0;
        if (link_target)
        {
            ret = stat(filepath.c_str(), &statbuf);
        }
        else
        {
            ret = lstat(filepath.c_str(), &statbuf);
        }

        if (ret != 0)
        {
            CUTL_ERROR("stat " + filepath + " error, ret:" + std::to_string(ret));
            return 0;
        }

        return static_cast<uint64_t>(statbuf.st_size);
    }

    filetype get_file_type(int mode)
    {
        filetype type = filetype::unknown;
        if (S_ISBLK(mode))
        {
            type = filetype::block_special;
        }
        else if (S_ISCHR(mode))
        {
            type = filetype::char_special;
        }
        else if (S_ISDIR(mode))
        {
            type = filetype::directory;
        }
        else if (S_ISFIFO(mode))
        {
            type = filetype::pipefifo;
        }

        else if (S_ISLNK(mode))
        {
            type = filetype::symlink;
        }
        else if (S_ISREG(mode))
        {
            type = filetype::file;
        }
        else if (S_ISSOCK(mode))
        {
            type = filetype::socket;
        }
        return type;
    }

    uint64_t get_dirsize(const std::string &dirpath)
    {
        uint64_t totalSize = 0;
        // filevec file_list;

        DIR *dir = opendir(dirpath.c_str()); // 打开这个目录
        if (dir == NULL)
        {
            CUTL_ERROR("opendir error. dirpath:" + dirpath + ", error:" + strerror(errno));
            return totalSize;
        }
        struct dirent *file_info = NULL;
        // 逐个读取目录中的文件到file_info
        while ((file_info = readdir(dir)) != NULL)
        {
            // 系统有个系统文件，名为“..”和“.”,对它不做处理
            std::string filename(file_info->d_name);
            if (is_special_dir(filename))
            {
                continue;
            }
            struct stat file_stat; // 文件的信息
            std::string filepath = dirpath + unix_separator + filename;
            int ret = lstat(filepath.c_str(), &file_stat);
            if (0 != ret)
            {
                CUTL_ERROR("stat error. filepath:" + filepath + ", error:" + strerror(errno));
                closedir(dir);
                return totalSize;
            }
            auto ftype = get_file_type(file_stat.st_mode);

            if (S_ISDIR(file_stat.st_mode))
            {
                auto subdir_size = get_dirsize(filepath);
                totalSize += subdir_size;
            }
            else
            {
                auto subfile_size = get_filesize(filepath, false);
                totalSize += subfile_size;
            }
        }
        closedir(dir);

        return totalSize;
    }
} // namespace cutl

#endif // defined(_WIN32) || defined(__WIN32__)

7. 源码地址

更多详细代码，请查看本人写的C++ 通用工具库: common_util, 本项目已开源，代码简洁，且有详细的文档和Demo。

博客内容遵循 署名-非商业性使用-相同方式共享 4.0 国际 (CC BY-NC-SA 4.0) 协议

本文永久链接是：http://sunlogging.com/2024/07/24/cpp_common_util/fileutil_file_dir_size/

更新：2024-07-24 22:46:06

C++

跨平台

文件系统操作

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