Directory Access Functions - POSIX

The directory access functions provide an API for iterating through the entries within a directory. The fs_opendir() function initiates this procedure, and each subsequent call to fs_readdir_r() (until all entries have been examined) returns information about a particular entry in a struct fs_dirent. The fs_closedir() function releases any file system structures and locks.

Listing - Directory listing example code gives an example using the directory access functions to list the files in a directory.

Listing - Directory listing example code

void  App_Fnct (void)
{
    FS_DIR             *p_dir;
    struct  fs_dirent   dirent;
    struct  fs_dirent  *p_dirent;
    char                str[50];
    char               *p_cwd_path;
    fs_time_t           ts;
    .
    .
    .
    p_dir = fs_opendir(p_cwd_path);                        /* Open dir.                      */
    if (p_dir != (FS_DIR *)0) {
        (void)fs_readdir_r(pdir, &dirent, &p_dirent);      /* Rd first dir entry.            */
        if (p_dirent == (FS_DIRENT *)0) {                  /* If NULL ... dir is empty.      */
            APP_TRACE_INFO(("Empty dir: %s.\r\n", p_cwd_path));   
        } else {                                           /* Fmt info for each entry.       */
            Str_Copy(str, "-r--r—r--                     :   ");
            while (p_dirent != (struct dirent *)0) {
                                                           /* Chk if file is dir.            */
                if (DEF_BIT_IS_SET(dirent.Info.Attrib, FS_ENTRY_ATTRIB_DIR) == DEF_YES) {
                    str[0] = 'd';
                }
                                                           /* Chk if file is rd only.        */
                if (DEF_BIT_IS_SET(dirent.Info.Attrib, FS_ENTRY_ATTRIB_WR) == DEF_YES) {
                    str[2] = 'w';
                    str[5] = 'w';
                    str[8] = 'w';
                }
                                                           /* Get file size.                 */
                if (p_dirent->Info.Size == 0) {
                    if (DEF_BIT_IS_CLR(dirent.Info.Attrib, FS_ENTRY_ATTRIB_DIR) == DEF_YES) {
                        Str_Copy(&str[11],"          0");
                    }
                } else {
                    Str_FmtNbr_Int32U(dirent.Info.Size, 
                                      10, 10, '0', DEF_NO, DEF_NO, &str[11]);
                }
                                                           /* Get file date/time.            */
                if (p_dirent->Info.DateTimeCreate.Month != 0) {
                    Str_Copy(&str[22], 
                         (CPU_CHAR *)App_MonthNames[dirent.Info.DateTimeCreate.Month - 1]);
                    Str_FmtNbr_Int32U(dirent.Info.DateTimeWr.Day,    
                                      2, 10, ' ', DEF_NO, DEF_NO, &str[26]);
                    Str_FmtNbr_Int32U(dirent.Info.DateTimeWr.Hour,  
                                      2, 10, ' ', DEF_NO, DEF_NO, &str[29]);
                    Str_FmtNbr_Int32U(dirent.Info.DateTimeWr.Minute, 
                                      2, 10, ' ', DEF_NO, DEF_NO, &str[32]);
                }
                                                           /* Output info for entry.         */
                APP_TRACE_INFO(("%s%s\r\n", str, dirent.Name));
                                                           /* Rd next dir entry.             */
                (void)fs_readdir_r(pdir, &dirent, &p_dirent);
            }
        }
 
        fs_closedir(p_dir);                                /* Close dir.                     */
                                                           /* If dir could not be opened ... */
    } else {                                               /* ... dir does not exist.        */
        APP_TRACE_INFO(("Dir does not exist: %s.\r\n", p_cwd_path));
    }
    .
    .
    .
}

An example result of listing a directory is shown in the figure below.

The second argument fs_readdir_r(), is a pointer to a struct fs_dirent, which has two members. The first is Name, which holds the name of the entry; the second is Info, which has file information. For more information about the struct fs_dirent structure, see FS_DIR_ENTRY (struct fs_dirent).