linux——3.文件操作

/* *       file.cpp: for linux file methods */#include <fcntl.h>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <stdio.h>#include <dirent.h>#include <iostream>using namespace std;#define UNIT_TEST   1// file classclass File{public:    File()    {        m_fd = -1;    }    ~File()    {        close();    }        /*    *       system lib call    */    // open    // oflags: O_RDONLY, O_WRONLY, O_RDWR; O_APPEND, O_TRUNC, O_CREAT, O_EXCL    // mode: S_IRUSR, S_IWUSR, S_IXUSR..    bool open(const char *path, int oflags = O_RDWR, int mode = S_IRUSR | S_IWUSR)    {        m_fd = ::open(path, oflags, mode);        return m_fd != -1;    }        // close    void close()    {        if (m_fd != -1)        {            ::close(m_fd);            m_fd = -1;        }    }        // write    size_t write(const void *buf, size_t nbytes)    {        if (m_fd != -1)        {            return ::write(m_fd, buf, nbytes);        }                return -1;    }        // read    size_t read(void *buf, size_t nbytes)    {        if (m_fd != -1)        {            return ::read(m_fd, buf, nbytes);        }                return -1;    }        // copy    static bool copy(const char *path, const char *pathout)    {        File in;        if (!in.open(path, O_RDONLY))        {            return false;        }                File out;        if (!out.open(pathout, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR))        {            return false;        }                char buf[1024];        int nread;        while ((nread = in.read(buf, sizeof(buf))) > 0)        {            out.write(buf, nread);        }                return true;    }        // seek    off_t lseek(off_t offset, int whence = SEEK_SET)    {        if (m_fd != -1)        {            return ::lseek(m_fd, offset, whence);        }        return -1;    }            /*     *       std io lib     */    // fopen, fclose, fread, fwrite, fflush, fsee,, fgetc, fputc, fprintf..        /*     *      maintain file and folder     */    // change file or folder access priority    static int chmod(const char *path, mode_t mode)    {        return ::chmod(path, mode);    }    protected:    int     m_fd;};// directoryclass Directory{public:    Directory()    {        m_dir = NULL;    }    ~Directory()    {        close();    }        // make dir    static int mkdir(const char *path, mode_t mode)    {        return ::mkdir(path, mode);    }        // remove dir    // only if the dir is empty    static int rmdir(const char *path)    {        return ::rmdir(path);    }        // change dir    static int chdir(const char *path)    {        return ::chdir(path);    }        // get current work directory    static char *getcwd(char *buf, size_t size)    {        return ::getcwd(buf, size);    }        // open dir    bool open(const char *name)    {        m_dir = ::opendir(name);        return m_dir != NULL;    }        // read dir    // dirent: d_ino inode num, d_name file name    dirent* read(DIR *dir = NULL)    {        if (!dir)            dir = m_dir;        if (dir)            return readdir(dir);                return NULL;    }        void close()    {        if (m_dir)        {            closedir(m_dir);            m_dir = NULL;        }    }        long int tell(DIR *dir = NULL)    {        if (!dir)            dir = m_dir;        if (dir)            return telldir(dir);                return -1;    }        void seek(DIR *dir = NULL, long int loc = 0)    {        if (!dir)            dir = m_dir;        if (dir)            seekdir(dir, loc);    }        // scan    static void scan(const char *path)    {        // open dir        Directory dir;        if (!dir.open(path))        {            cout << "open dir failed:" << path << endl;            return;        }                // change dir        chdir(path);                // scan dir        struct dirent *entry;        struct stat statbuf;        while ((entry = dir.read()) != NULL)        {            lstat(entry->d_name, &statbuf);            if (S_ISDIR(statbuf.st_mode))            {                // found a dir, but ignore . and ..                if (!strcmp(".", entry->d_name)                    || !strcmp("..", entry->d_name))                {                    continue;                }                scan(entry->d_name);            }            else            {                cout << entry->d_name << endl;            }        }                chdir("..");        dir.close();    }protected:    DIR*    m_dir;};#if UNIT_TEST == 1int main(){    File file;        // create open.txt    if (!file.open("open.txt", O_RDWR | O_CREAT))    {        cout << "create file open.txt error.\n";    }    else    {        // write        char buf[] = "this is adfan\nit's true\n";        file.write(buf, sizeof(buf));                file.close();    }        // open    if (!file.open("open.txt"))    {        cout << "open file open.txt error.\n";    }    else    {        char buf[256] = {0};        file.read(buf, 256);        cout << buf << endl;    }            // close file    file.close();        // copy    File::copy("open.txt", "open_out.txt");        char dir[256];    cout << Directory::getcwd(dir, 256) << endl;        // scan    Directory::scan(dir);}#endif