interface/wx/ffile.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        ffile.h
   3 // Purpose:     interface of wxFFile
   4 // Author:      wxWidgets team
   5 // Licence:     wxWindows licence
   6 /////////////////////////////////////////////////////////////////////////////
   7
   8
   9 /**
  10     @class wxFFile
  11
  12     wxFFile implements buffered file I/O.
  13
  14     This is a very small class designed to minimize the overhead of using it - in fact,
  15     there is hardly any overhead at all, but using it brings you automatic error checking
  16     and hides differences between platforms and compilers.
  17
  18     It wraps inside it a @c FILE * handle used by standard C IO library (also known as @c stdio).
  19
  20     @library{wxbase}
  21     @category{file}
  22
  23     @see wxFFile::IsOpened
  24 */
  25 class wxFFile
  26 {
  27 public:
  28     wxFFile();
  29
  30     /**
  31         Opens a file with the given file pointer, which has already been opened.
  32
  33         @param fp
  34             An existing file descriptor, such as stderr.
  35     */
  36     wxFFile(FILE* fp);
  37
  38     /**
  39         Opens a file with the given mode.
  40         As there is no way to return whether the operation was successful or not from
  41         the constructor you should test the return value of IsOpened() to check that it
  42         didn't fail.
  43
  44         @param filename
  45             The filename.
  46         @param mode
  47             The mode in which to open the file using standard C strings.
  48             Note that you should use "b" flag if you use binary files under Windows
  49             or the results might be unexpected due to automatic newline conversion done
  50             for the text files.
  51     */
  52     wxFFile(const wxString& filename, const wxString& mode = "r");
  53
  54
  55     /**
  56         Destructor will close the file.
  57
  58         @note it is not virtual so you should @e not derive from wxFFile!
  59     */
  60     ~wxFFile();
  61
  62     /**
  63         Attaches an existing file pointer to the wxFFile object.
  64
  65         The descriptor should be already opened and it will be closed by wxFFile object.
  66     */
  67     void Attach(FILE* fp, const wxString& name = wxEmptyString);
  68
  69     /**
  70         Closes the file and returns @true on success.
  71     */
  72     bool Close();
  73
  74     /**
  75         Get back a file pointer from wxFFile object -- the caller is responsible for
  76         closing the file if this descriptor is opened.
  77
  78         IsOpened() will return @false after call to Detach().
  79     */
  80     void Detach();
  81
  82     /**
  83         Returns @true if an attempt has been made to read @e past
  84         the end of the file.
  85
  86         Note that the behaviour of the file descriptor based class  wxFile is different as
  87         wxFile::Eof() will return @true here as soon as the last byte of the file has been read.
  88
  89         Also note that this method may only be called for opened files and may crash if
  90         the file is not opened.
  91
  92         @todo THIS METHOD MAY CRASH? DOESN'T SOUND GOOD
  93
  94         @see IsOpened()
  95     */
  96     bool Eof() const;
  97
  98     /**
  99         Returns @true if an error has occurred on this file, similar to the standard
 100         @c ferror() function.
 101
 102         Please note that this method may only be called for opened files and may crash
 103         if the file is not opened.
 104
 105         @todo THIS METHOD MAY CRASH? DOESN'T SOUND GOOD
 106
 107         @see IsOpened()
 108     */
 109     bool Error() const;
 110
 111     /**
 112         Flushes the file and returns @true on success.
 113     */
 114     bool Flush();
 115
 116     /**
 117         Returns the type of the file.
 118
 119         @see wxFileKind
 120     */
 121     wxFileKind GetKind() const;
 122
 123     /**
 124         Returns the file name.
 125
 126         This is the name that was specified when the object was constructed or
 127         to the last call to Open(). Notice that it may be empty if Attach() was
 128         called without specifying the name.
 129      */
 130     const wxString& GetName() const;
 131
 132     /**
 133         Returns @true if the file is opened.
 134
 135         Most of the methods of this class may only be used for an opened file.
 136     */
 137     bool IsOpened() const;
 138
 139     /**
 140         Returns the length of the file.
 141     */
 142     wxFileOffset Length() const;
 143
 144     /**
 145         Opens the file, returning @true if successful.
 146
 147         @param filename
 148             The filename.
 149         @param mode
 150             The mode in which to open the file.
 151     */
 152     bool Open(const wxString& filename, const wxString& mode = "r");
 153
 154     /**
 155         Reads the specified number of bytes into a buffer, returning the actual number read.
 156
 157         @param buffer
 158             A buffer to receive the data.
 159         @param count
 160             The number of bytes to read.
 161
 162         @return The number of bytes read.
 163     */
 164     size_t Read(void* buffer, size_t count);
 165
 166     /**
 167         Reads the entire contents of the file into a string.
 168
 169         @param str
 170             String to read data into.
 171         @param conv
 172             Conversion object to use in Unicode build; by default supposes
 173             that file contents is encoded in UTF-8.
 174
 175         @return @true if file was read successfully, @false otherwise.
 176     */
 177     bool ReadAll(wxString* str, const wxMBConv& conv = wxConvAuto());
 178
 179     /**
 180         Seeks to the specified position and returns @true on success.
 181
 182         @param ofs
 183             Offset to seek to.
 184         @param mode
 185             One of wxFromStart, wxFromEnd, wxFromCurrent.
 186     */
 187     bool Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
 188
 189     /**
 190         Moves the file pointer to the specified number of bytes before the end of the
 191         file and returns @true on success.
 192
 193         @param ofs
 194             Number of bytes before the end of the file.
 195     */
 196     bool SeekEnd(wxFileOffset ofs = 0);
 197
 198     /**
 199         Returns the current position.
 200     */
 201     wxFileOffset Tell() const;
 202
 203     /**
 204         Writes the contents of the string to the file, returns @true on success.
 205
 206         The second argument is only meaningful in Unicode build of wxWidgets when
 207         @a conv is used to convert @a str to multibyte representation.
 208     */
 209     bool Write(const wxString& str, const wxMBConv& conv = wxConvAuto());
 210
 211     /**
 212         Writes the specified number of bytes from a buffer.
 213
 214         @param buffer
 215             A buffer containing the data.
 216         @param count
 217             The number of bytes to write.
 218
 219         @return The number of bytes written.
 220     */
 221     size_t Write(const void* buffer, size_t count);
 222
 223     /**
 224         Returns the file pointer associated with the file.
 225     */
 226     FILE* fp() const;
 227 };
 228