C++文件路径处理2 - 路径拼接&路径解析

[1. 关键词](#1. 关键词)
[2. filesystem.h](#2. filesystem.h)
[3. filepath.cpp](#3. filepath.cpp)
[6. 测试代码](#6. 测试代码)
[7. 运行结果](#7. 运行结果)
[8. 源码地址](#8. 源码地址)

1. 关键词

关键词：

C++ 文件路径处理路径拼接获取父目录的路径获取文件名获取拓展名跨平台

应用场景：

路径的拼接
路径的解析

2. filesystem.h

c++ 复制代码

#pragma once

#include <string>
#include <iostream>
#include <cstdio>
#include "filetype.h"

namespace cutl
{

    /**
     * @brief The class for file path operations.
     *
     */
    class filepath
    {
    public:
        /**
         * @brief Construct a new filepath object
         *
         * @param path file path string
         */
        filepath(const std::string &path);

        /**
         * @brief Construct a new filepath object by copy
         *
         * @param other other filepath object
         */
        filepath(const filepath &other);

        /**
         * @brief Assign operator, assign a new filepath object by copy
         *
         * @param other other filepath object
         * @return filepath& the reference of the current filepath object
         */
        filepath &operator=(const filepath &other);

        /**
         * @brief Destroy the filepath object
         *
         */
        ~filepath() = default;

    public:
        /**
         * @brief Get the path separator of the current os platform.
         *
         * @return the path separator
         */
        static char separator();

        /**
         * @brief Get the string of the filepath.
         *
         * @return the filepath
         */
        std::string str() const;

        /**
         * @brief Join the current filepath with a new filename.
         *
         * @param filename the filename to be joined
         * @return the new filepath object
         */
        filepath join(const std::string &filename) const;

        /**
         * @brief Get the parent directory of the filepath.
         *
         * @return parent directory path
         */
        std::string dirname() const;

        /**
         * @brief Get the filename or directory name of the filepath.
         *
         * @return filename or directory name
         */
        std::string basename() const;
        /**
         * @brief Get the extension of the filepath.
         *
         * @return extension with dot
         */
        std::string extension() const;

    private:
        std::string filepath_;
    };

    /**
     * @brief Define the output stream operator for filepath object.
     *
     * @param os the std::ostream object
     * @param fp the filepath object to be output
     * @return std::ostream& the reference of the std::ostream object after outputing the filepath object.
     */
    std::ostream &operator<<(std::ostream &os, const filepath &fp);

    /**
     * @brief Create a filepath object from a string.
     *
     * @param path file path string
     * @return filepath object
     */
    filepath path(const std::string &path);

} // namespace cutl

3. filepath.cpp

c++ 复制代码

#include "filepath.h"
#include "inner/logger.h"
#include "inner/filesystem.h"
#include "strutil.h"
#include "sysutil.h"

namespace cutl
{
    static constexpr char win_separator = '\\';
    static constexpr char unix_separator = '/';

    void fixpath(std::string &path)
    {
        if (win_separator == filepath::separator())
        {
            for (size_t i = 0; i < path.size(); i++)
            {
                if (path[i] == unix_separator)
                {
                    path[i] = win_separator;
                }
            }
        }
        else if (unix_separator == filepath::separator())
        {
            for (size_t i = 0; i < path.size(); i++)
            {
                if (path[i] == win_separator)
                {
                    path[i] = unix_separator;
                }
            }
        }
        else
        {
            // do nothing
        }

        while (path.empty() || path.back() == filepath::separator())
        {
            path.pop_back();
        }
    }

    filepath::filepath(const std::string &path)
    {
        filepath_ = path;
        fixpath(filepath_);
    }

    filepath::filepath(const filepath &other)
    {
        filepath_ = other.filepath_;
    }

    filepath &filepath::operator=(const filepath &other)
    {
        this->filepath_ = other.filepath_;
        return *this;
    }

    char filepath::separator()
    {
#if defined(_WIN32) || defined(__WIN32__)
        return win_separator;
#else
        return unix_separator;
#endif
    }

    std::string filepath::str() const
    {
        return filepath_;
    }

    filepath filepath::join(const std::string &filename) const
    {
        std::string path = filepath_ + separator() + filename;
        return filepath(path);
    }

    std::string filepath::dirname() const
    {
        auto index = filepath_.find_last_of(separator());
        if (index == std::string::npos)
        {
            return "";
        }
        return filepath_.substr(0, index);
    }

    std::string filepath::basename() const
    {
        auto index = filepath_.find_last_of(separator());
        // auto len = filepath_.length() - index - 1;
        if (index == std::string::npos)
        {
            return filepath_;
        }
        return filepath_.substr(index + 1);
    }

    std::string filepath::extension() const
    {
        auto pos = filepath_.find_last_of('.');
        if (pos == std::string::npos)
        {
            return "";
        }

        return filepath_.substr(pos);
    }

    std::ostream &operator<<(std::ostream &os, const filepath &fp)
    {
        os << fp.str();
        return os;
    }

    filepath path(const std::string &path)
    {
        return filepath(path);
    }
} // namespace cutl

6. 测试代码

c++ 复制代码

#include "common.hpp"
#include "fileutil.h"

void TestJoin()
{
    PrintSubTitle("TestJoin");

    auto path1 = cutl::path("/Users/spencer/workspace/common_util/src/usage_demo");
    auto path2 = path1.join("filepath.hpp");

    std::cout << "path1: " << path1 << std::endl;
    std::cout << "path2: " << path2 << std::endl;
}

void TestDirnameBasename()
{
    PrintSubTitle("TestDirnameBasename");

    auto path1 = cutl::path("/Users/spencer/workspace/common_util/src/usage_demo/filepath.hpp");
    std::cout << "path1: " << path1 << std::endl;
    std::cout << "dirname: " << path1.dirname() << std::endl;
    std::cout << "basename: " << path1.basename() << std::endl;
    auto path2 = cutl::path("/Users/spencer/workspace/common_util/src/usage_demo");
    std::cout << "path2: " << path2 << std::endl;
    std::cout << "dirname: " << path2.dirname() << std::endl;
    std::cout << "basename: " << path2.basename() << std::endl;
    auto path3 = cutl::path("filepath.hpp");
    std::cout << "path3: " << path3 << std::endl;
    std::cout << "dirname: " << path3.dirname() << std::endl;
    std::cout << "basename: " << path3.basename() << std::endl;
}

void TestExtenstion()
{
    PrintSubTitle("TestExtenstion");

    auto path1 = cutl::path("/Users/spencer/workspace/common_util/src/usage_demo/filepath.hpp");
    std::cout << "path1: " << path1 << ", extension: " << path1.extension() << std::endl;
    auto path2 = cutl::path("/Users/spencer/workspace/common_util/src/usage_demo/filepath");
    std::cout << "path2: " << path2 << ", extension: " << path2.extension() << std::endl;
}

7. 运行结果

bash 复制代码

----------------------------------------------TestJoin----------------------------------------------
path1: /Users/spencer/workspace/common_util/src/usage_demo
path2: /Users/spencer/workspace/common_util/src/usage_demo/filepath.hpp
----------------------------------------TestDirnameBasename-----------------------------------------
path1: /Users/spencer/workspace/common_util/src/usage_demo/filepath.hpp
dirname: /Users/spencer/workspace/common_util/src/usage_demo
basename: filepath.hpp
path2: /Users/spencer/workspace/common_util/src/usage_demo
dirname: /Users/spencer/workspace/common_util/src
basename: usage_demo
path3: filepath.hpp
dirname: 
basename: filepath.hpp
-------------------------------------------TestExtenstion-------------------------------------------
path1: /Users/spencer/workspace/common_util/src/usage_demo/filepath.hpp, extension: .hpp
path2: /Users/spencer/workspace/common_util/src/usage_demo/filepath, extension:

8. 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。

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