interface/wx/textfile.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        textfile.h
   3 // Purpose:     interface of wxTextFile
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9
  10 /** The line termination type (kept wxTextFileType name for compability) */
  11 enum wxTextFileType
  12 {
  13     wxTextFileType_None,  //!< incomplete (the last line of the file only)
  14     wxTextFileType_Unix,  //!< line is terminated with 'LF' = 0xA = 10 = '\n'
  15     wxTextFileType_Dos,   //!< line is terminated with 'CR' 'LF'
  16     wxTextFileType_Mac,   //!< line is terminated with 'CR' = 0xD = 13 = '\r'
  17     wxTextFileType_Os2    //!< line is terminated with 'CR' 'LF'
  18 };
  19
  20
  21 /**
  22     @class wxTextFile
  23
  24     The wxTextFile is a simple class which allows to work with text files on line by
  25     line basis. It also understands the differences in line termination characters
  26     under different platforms and will not do anything bad to files with "non
  27     native" line termination sequences - in fact, it can be also used to modify the
  28     text files and change the line termination characters from one type (say DOS) to
  29     another (say Unix).
  30
  31     One word of warning: the class is not at all optimized for big files and thus
  32     it will load the file entirely into memory when opened. Of course, you should
  33     not work in this way with large files (as an estimation, anything over 1 Megabyte
  34     is surely too big for this class). On the other hand, it is not a serious
  35     limitation for small files like configuration files or program sources
  36     which are well handled by wxTextFile.
  37
  38     The typical things you may do with wxTextFile in order are:
  39
  40     - Create and open it: this is done with either wxTextFile::Create or wxTextFile::Open
  41       function which opens the file (name may be specified either as the argument to
  42       these functions or in the constructor), reads its contents in memory (in the
  43       case of @c Open()) and closes it.
  44     - Work with the lines in the file: this may be done either with "direct
  45       access" functions like wxTextFile::GetLineCount and wxTextFile::GetLine
  46       (@e operator[] does exactly the same but looks more like array addressing)
  47       or with "sequential access" functions which include wxTextFile::GetFirstLine,
  48       wxTextFile::GetNextLine and also wxTextFile::GetLastLine, wxTextFile::GetPrevLine.
  49       For the sequential access functions the current line number is maintained: it is
  50       returned by wxTextFile::GetCurrentLine and may be changed with wxTextFile::GoToLine.
  51     - Add/remove lines to the file: wxTextFile::AddLine and wxTextFile::InsertLine
  52       add new lines while wxTextFile::RemoveLine deletes the existing ones.
  53       wxTextFile::Clear resets the file to empty.
  54     - Save your changes: notice that the changes you make to the file will @b not be
  55       saved automatically; calling wxTextFile::Close or doing nothing discards them!
  56       To save the changes you must explicitly callwxTextFile::Write - here, you may
  57       also change the line termination type if you wish.
  58
  59
  60     @library{wxbase}
  61     @category{file}
  62
  63     @see wxFile
  64 */
  65 class wxTextFile
  66 {
  67 public:
  68     /**
  69         Default constructor, use Create() or Open() with a file name parameter to
  70         initialize the object.
  71     */
  72     wxTextFile();
  73
  74     /**
  75         Constructor does not load the file into memory, use Open() to do it.
  76     */
  77     wxTextFile(const wxString& strFile);
  78
  79     /**
  80         Destructor does nothing.
  81     */
  82     virtual ~wxTextFile();
  83
  84     /**
  85         Adds a line to the end of file.
  86     */
  87     void AddLine(const wxString& str,
  88                  wxTextFileType type = typeDefault) const;
  89
  90     /**
  91         Delete all lines from the file, set current line number to 0.
  92     */
  93     void Clear() const;
  94
  95     /**
  96         Closes the file and frees memory, @b "losing all changes".
  97         Use Write() if you want to save them.
  98     */
  99     bool Close() const;
 100
 101     //@{
 102     /**
 103         Creates the file with the given name or the name which was given in the
 104         @ref ctor() constructor. The array of file lines is initially empty.
 105
 106         It will fail if the file already exists, Open() should be used in this case.
 107     */
 108     bool Create() const;
 109     bool Create(const wxString& strFile) const;
 110     //@}
 111
 112     /**
 113         Returns @true if the current line is the last one.
 114     */
 115     bool Eof() const;
 116
 117     /**
 118         Return @true if file exists - the name of the file should have been specified
 119         in the constructor before calling Exists().
 120     */
 121     bool Exists() const;
 122
 123     /**
 124         Returns the current line: it has meaning only when you're using
 125         GetFirstLine()/GetNextLine() functions, it doesn't get updated when
 126         you're using "direct access" functions like GetLine().
 127         GetFirstLine() and GetLastLine() also change the value of the current line,
 128         as well as GoToLine().
 129     */
 130     size_t GetCurrentLine() const;
 131
 132     /**
 133         Get the line termination string corresponding to given constant.
 134
 135         @e typeDefault is the value defined during the compilation and corresponds
 136         to the native format of the platform, i.e. it will be @c wxTextFileType_Dos
 137         under Windows, @c wxTextFileType_Unix under Unix (including Mac OS X when
 138         compiling with the Apple Developer Tools) and @c wxTextFileType_Mac under
 139         Mac OS (including Mac OS X when compiling with CodeWarrior).
 140     */
 141     static const char* GetEOL(wxTextFileType type = typeDefault) const;
 142
 143     /**
 144         This method together with GetNextLine() allows more "iterator-like"
 145         traversal of the list of lines, i.e. you may write something like:
 146
 147         @code
 148         wxTextFile file;
 149         ...
 150         for ( str = file.GetFirstLine(); !file.Eof(); str = file.GetNextLine() )
 151         {
 152             // do something with the current line in str
 153         }
 154         // do something with the last line in str
 155         @endcode
 156     */
 157     wxString GetFirstLine() const;
 158
 159     /**
 160         Gets the last line of the file.
 161
 162         Together with GetPrevLine() it allows to enumerate the lines
 163         in the file from the end to the beginning like this:
 164
 165         @code
 166         wxTextFile file;
 167         ...
 168         for ( str = file.GetLastLine();
 169             file.GetCurrentLine() > 0;
 170             str = file.GetPrevLine() )
 171         {
 172             // do something with the current line in str
 173         }
 174         // do something with the first line in str
 175         @endcode
 176     */
 177     wxString GetLastLine();
 178
 179     /**
 180         Retrieves the line number @a n from the file.
 181
 182         The returned line may be modified but you shouldn't add line terminator
 183         at the end - this will be done by wxTextFile.
 184     */
 185     wxString GetLine(size_t n) const;
 186
 187     /**
 188         Get the number of lines in the file.
 189     */
 190     size_t GetLineCount() const;
 191
 192     /**
 193         Get the type of the line (see also wxTextFile::GetEOL).
 194     */
 195     wxTextFileType GetLineType(size_t n) const;
 196
 197     /**
 198         Get the name of the file.
 199     */
 200     const char* GetName() const;
 201
 202     /**
 203         Gets the next line (see GetFirstLine() for the example).
 204     */
 205     wxString GetNextLine();
 206
 207     /**
 208         Gets the previous line in the file.
 209     */
 210     wxString GetPrevLine();
 211
 212     /**
 213         Changes the value returned by GetCurrentLine() and used by GetFirstLine()
 214         and GetNextLine().
 215     */
 216     void GoToLine(size_t n) const;
 217
 218     /**
 219         Guess the type of file (which is supposed to be opened).
 220
 221         If sufficiently many lines of the file are in DOS/Unix/Mac format,
 222         the corresponding value will be returned.
 223         If the detection mechanism fails @c wxTextFileType_None is returned.
 224     */
 225     wxTextFileType GuessType() const;
 226
 227     /**
 228         Insert a line before the line number @a n.
 229     */
 230     void InsertLine(const wxString& str, size_t n,
 231                     wxTextFileType type = typeDefault) const;
 232
 233     /**
 234         Returns @true if the file is currently opened.
 235     */
 236     bool IsOpened() const;
 237
 238     //@{
 239     /**
 240         Open() opens the file with the given name or the name which was given in the
 241         @ref ctor() constructor and also loads file in memory on success.
 242
 243         It will fail if the file does not exist, Create() should be used in this case.
 244
 245         The @a conv argument is only meaningful in Unicode build of wxWidgets when
 246         it is used to convert the file to wide character representation.
 247     */
 248     bool Open(const wxMBConv& conv = wxConvAuto()) const;
 249     bool Open(const wxString& strFile, const wxMBConv& conv = wxConvAuto()) const;
 250     //@}
 251
 252     /**
 253         Delete line number @a n from the file.
 254     */
 255     void RemoveLine(size_t n) const;
 256
 257     /**
 258         Change the file on disk.
 259
 260         The @a typeNew parameter allows you to change the file format
 261         (default argument means "don't change type") and may be used to convert,
 262         for example, DOS files to Unix.
 263
 264         The @a conv argument is only meaningful in Unicode build of wxWidgets when
 265         it is used to convert all lines to multibyte representation before writing them
 266         them to physical file.
 267
 268         @return
 269             @true if operation succeeded, @false if it failed.
 270     */
 271     bool Write(wxTextFileType typeNew = wxTextFileType_None,
 272                const wxMBConv& conv = wxConvAuto()) const;
 273
 274     /**
 275         The same as GetLine().
 276     */
 277     wxString operator[](size_t n) const;
 278 };
 279