DirHandle.h

00001 /* mbed Microcontroller Library - DirHandler
00002  * Copyright (c) 2008-2009 ARM Limited. All rights reserved.
00003  */ 
00004  
00005 #ifndef MBED_DIRHANDLE_H
00006 #define MBED_DIRHANDLE_H
00007 
00008 #ifdef __ARMCC_VERSION
00009 # define NAME_MAX 255
00010 typedef int mode_t;
00011 #else
00012 # include <sys/syslimits.h>
00013 #endif
00014 #include "FileHandle.h"
00015 
00016 struct dirent {
00017     char d_name[NAME_MAX+1];
00018 };
00019 
00020 namespace mbed {
00021 
00022 /** Represents a directory stream. Objects of this type are returned
00023  *  by a FileSystemLike's opendir method. Implementations must define
00024  *  at least closedir, readdir and rewinddir.
00025  *
00026  *  If a FileSystemLike class defines the opendir method, then the
00027  *  directories of an object of that type can be accessed by 
00028  *  DIR *d = opendir("/example/directory") (or opendir("/example") 
00029  *  to open the root of the filesystem), and then using readdir(d) etc.
00030  *
00031  *  The root directory is considered to contain all FileLike and
00032  *  FileSystemLike objects, so the DIR* returned by opendir("/") will
00033  *  reflect this.
00034  */
00035 class DirHandle {
00036 
00037  public:
00038     /** Closes the directory.
00039      *
00040      *  @returns
00041      *    0 on success,
00042      *   -1 on error.
00043      */
00044     virtual int closedir()=0;
00045 
00046     /** Return the directory entry at the current position, and
00047      *  advances the position to the next entry.
00048      *
00049      * @returns
00050      *   A pointer to a dirent structure representing the
00051      *   directory entry at the current position, or NULL on reaching
00052      *   end of directory or error.
00053      */
00054     virtual struct dirent *readdir()=0;
00055 
00056     /** Resets the position to the beginning of the directory.
00057      */
00058     virtual void rewinddir()=0;
00059 
00060     /** Returns the current position of the DirHandle.
00061      *
00062      * @returns
00063      *   the current position,
00064      *  -1 on error.
00065      */
00066     virtual off_t telldir() { return -1; }
00067 
00068     /** Sets the position of the DirHandle.
00069      *
00070      *  @param location The location to seek to. Must be a value returned by telldir.
00071      */
00072     virtual void seekdir(off_t location) { }
00073 
00074 };
00075 
00076 } // namespace mbed
00077 
00078 typedef mbed::DirHandle DIR;
00079 
00080 extern "C" {
00081     DIR *opendir(const char*);
00082     struct dirent *readdir(DIR *);
00083     int closedir(DIR*);
00084     void rewinddir(DIR*);
00085     long telldir(DIR*);
00086     void seekdir(DIR*, long);
00087     int mkdir(const char *name, mode_t n);
00088 };
00089 
00090 #endif /* MBED_DIRHANDLE_H */