interface/textfile.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        textfile.h
   3 // Purpose:     documentation for wxTextFile class
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxTextFile
  11     @wxheader{textfile.h}
  12
  13     The wxTextFile is a simple class which allows to work with text files on line by
  14     line basis. It also understands the differences in line termination characters
  15     under different platforms and will not do anything bad to files with "non
  16     native" line termination sequences - in fact, it can be also used to modify the
  17     text files and change the line termination characters from one type (say DOS) to
  18     another (say Unix).
  19
  20     One word of warning: the class is not at all optimized for big files and thus
  21     it will load the file entirely into memory when opened. Of course, you should
  22     not
  23     work in this way with large files (as an estimation, anything over 1 Megabyte is
  24     surely too big for this class). On the other hand, it is not a serious
  25     limitation for small files like configuration files or program sources
  26     which are well handled by wxTextFile.
  27
  28     The typical things you may do with wxTextFile in order are:
  29
  30      Create and open it: this is done with either
  31     wxTextFile::Create or wxTextFile::Open
  32     function which opens the file (name may be specified either as the argument to
  33     these functions or in the constructor), reads its contents in memory (in the
  34     case of @c Open()) and closes it.
  35      Work with the lines in the file: this may be done either with "direct
  36     access" functions like wxTextFile::GetLineCount and
  37     wxTextFile::GetLine (@e operator[] does exactly the same
  38     but looks more like array addressing) or with "sequential access" functions
  39     which include wxTextFile::GetFirstLine/
  40     wxTextFile::GetNextLine and also
  41     wxTextFile::GetLastLine/wxTextFile::GetPrevLine.
  42     For the sequential access functions the current line number is maintained: it is
  43     returned by wxTextFile::GetCurrentLine and may be
  44     changed with wxTextFile::GoToLine.
  45      Add/remove lines to the file: wxTextFile::AddLine and
  46     wxTextFile::InsertLine add new lines while
  47     wxTextFile::RemoveLine deletes the existing ones.
  48     wxTextFile::Clear resets the file to empty.
  49      Save your changes: notice that the changes you make to the file will @b not be
  50     saved automatically; calling wxTextFile::Close or doing
  51     nothing discards them! To save the changes you must explicitly call
  52     wxTextFile::Write - here, you may also change the line
  53     termination type if you wish.
  54
  55
  56     @library{wxbase}
  57     @category{file}
  58
  59     @seealso
  60     wxFile
  61 */
  62 class wxTextFile
  63 {
  64 public:
  65     /**
  66         Constructor does not load the file into memory, use Open() to do it.
  67     */
  68     wxTextFile(const wxString& strFile);
  69
  70     /**
  71         Destructor does nothing.
  72     */
  73     ~wxTextFile();
  74
  75     /**
  76         Adds a line to the end of file.
  77     */
  78     void AddLine(const wxString& str,
  79                  wxTextFileType type = typeDefault);
  80
  81     /**
  82         Delete all lines from the file, set current line number to 0.
  83     */
  84     void Clear();
  85
  86     /**
  87         Closes the file and frees memory, @b losing all changes. Use Write()
  88         if you want to save them.
  89     */
  90     bool Close();
  91
  92     //@{
  93     /**
  94         Creates the file with the given name or the name which was given in the
  95         @ref ctor() constructor. The array of file lines is initially
  96         empty.
  97
  98         It will fail if the file already exists, Open() should
  99         be used in this case.
 100     */
 101     bool Create();
 102     bool Create(const wxString& strFile);
 103     //@}
 104
 105     /**
 106         Returns @true if the current line is the last one.
 107     */
 108 #define bool Eof()     /* implementation is private */
 109
 110     /**
 111         Return @true if file exists - the name of the file should have been specified
 112         in the constructor before calling Exists().
 113     */
 114     bool Exists();
 115
 116     /**
 117         Returns the current line: it has meaning only when you're using
 118         GetFirstLine()/GetNextLine() functions, it doesn't get updated when
 119         you're using "direct access" functions like GetLine(). GetFirstLine() and
 120         GetLastLine() also change the value of the current line, as well as
 121         GoToLine().
 122     */
 123     size_t GetCurrentLine();
 124
 125     /**
 126         Get the line termination string corresponding to given constant. @e typeDefault
 127         is
 128         the value defined during the compilation and corresponds to the native format
 129         of the platform, i.e. it will be wxTextFileType_Dos under Windows,
 130         wxTextFileType_Unix under Unix (including Mac OS X when compiling with the
 131         Apple Developer Tools) and wxTextFileType_Mac under Mac OS (including
 132         Mac OS X when compiling with CodeWarrior).
 133     */
 134 #define static const char* GetEOL(wxTextFileType type = typeDefault)     /* implementation is private */
 135
 136     /**
 137         This method together with GetNextLine()
 138         allows more "iterator-like" traversal of the list of lines, i.e. you may
 139         write something like:
 140     */
 141     wxString GetFirstLine();
 142
 143     /**
 144         Gets the last line of the file. Together with
 145         GetPrevLine() it allows to enumerate the lines
 146         in the file from the end to the beginning like this:
 147     */
 148     wxString GetLastLine();
 149
 150     /**
 151         Retrieves the line number @e n from the file. The returned line may be
 152         modified but you shouldn't add line terminator at the end - this will be done
 153         by wxTextFile.
 154     */
 155     wxString GetLine(size_t n);
 156
 157     /**
 158         Get the number of lines in the file.
 159     */
 160     size_t GetLineCount();
 161
 162     /**
 163         Get the type of the line (see also wxTextFile::GetEOL)
 164     */
 165     wxTextFileType GetLineType(size_t n);
 166
 167     /**
 168         Get the name of the file.
 169     */
 170     const char* GetName();
 171
 172     /**
 173         Gets the next line (see GetFirstLine() for
 174         the example).
 175     */
 176     wxString GetNextLine();
 177
 178     /**
 179         Gets the previous line in the file.
 180     */
 181     wxString GetPrevLine();
 182
 183     /**
 184         Changes the value returned by GetCurrentLine()
 185         and used by wxTextFile::GetFirstLine/GetNextLine().
 186     */
 187     void GoToLine(size_t n);
 188
 189     /**
 190         Guess the type of file (which is supposed to be opened). If sufficiently
 191         many lines of the file are in DOS/Unix/Mac format, the corresponding value will
 192         be returned. If the detection mechanism fails wxTextFileType_None is returned.
 193     */
 194     wxTextFileType GuessType();
 195
 196     /**
 197         Insert a line before the line number @e n.
 198     */
 199     void InsertLine(const wxString& str, size_t n,
 200                     wxTextFileType type = typeDefault);
 201
 202     /**
 203         Returns @true if the file is currently opened.
 204     */
 205     bool IsOpened();
 206
 207     //@{
 208     /**
 209         )
 210
 211         Open() opens the file with the given name or the name which was given in the
 212         @ref ctor() constructor and also loads file in memory on
 213         success. It will fail if the file does not exist,
 214         Create() should be used in this case.
 215
 216         The @e conv argument is only meaningful in Unicode build of wxWidgets when
 217         it is used to convert the file to wide character representation.
 218     */
 219     bool Open();
 220     bool Open(const wxString& strFile);
 221     //@}
 222
 223     /**
 224         Delete line number @e n from the file.
 225     */
 226     void RemoveLine(size_t n);
 227
 228     /**
 229         )
 230
 231         Change the file on disk. The @e typeNew parameter allows you to change the
 232         file format (default argument means "don't change type") and may be used to
 233         convert, for example, DOS files to Unix.
 234
 235         The @e conv argument is only meaningful in Unicode build of wxWidgets when
 236         it is used to convert all lines to multibyte representation before writing them
 237         them to physical file.
 238
 239         Returns @true if operation succeeded, @false if it failed.
 240     */
 241     bool Write(wxTextFileType typeNew = wxTextFileType_None);
 242
 243     /**
 244         The same as GetLine().
 245     */
 246     wxString operator[](size_t n);
 247 };