QFile Class Reference

The QFile class is an I/O device that operates on files. More...

#include <qfile.h>

Inheritance diagram for QFile:

Public Types
typedef QCString(*	EncoderFn) (const QString &fileName)
typedef QString(*	DecoderFn) (const QCString &localfileName)

Public Member Functions
	QFile ()
	QFile (const QString &name)
virtual	~QFile ()
QString	name () const
void	setName (const QString &name)
bool	exists () const
bool	remove ()
bool	open (int)
bool	open (int, FILE *)
bool	open (int, int)
void	close ()
void	flush ()
uint	size () const
int	at () const
bool	at (int)
bool	atEnd () const
int	readBlock (char *data, uint len)
int	writeBlock (const char *data, uint len)
int	writeBlock (const QByteArray &data)
int	readLine (char *data, uint maxlen)
int	readLine (QString &, uint maxlen)
int	getch ()
int	putch (int)
int	ungetch (int)
int	handle () const
int64	pos () const
int64	toEnd ()
bool	seek (int64 pos)
Public Member Functions inherited from QIODevice
	QIODevice ()
virtual	~QIODevice ()
int	flags () const
int	mode () const
int	state () const
bool	isDirectAccess () const
bool	isSequentialAccess () const
bool	isCombinedAccess () const
bool	isBuffered () const
bool	isRaw () const
bool	isSynchronous () const
bool	isAsynchronous () const
bool	isTranslated () const
bool	isReadable () const
bool	isWritable () const
bool	isReadWrite () const
bool	isInactive () const
bool	isOpen () const
int	status () const
void	resetStatus ()
bool	reset ()
int	writeBlock (const QByteArray &data)
QByteArray	readAll ()

Static Public Member Functions
static QCString	encodeName (const QString &fileName)
static QString	decodeName (const QCString &localFileName)
static void	setEncodingFunction (EncoderFn)
static void	setDecodingFunction (DecoderFn)
static bool	exists (const QString &fileName)
static bool	remove (const QString &fileName)

Protected Attributes
QString	fn
FILE *	fh
int	fd
int	length
bool	ext_f
void *	d
Protected Attributes inherited from QIODevice
int	ioIndex

Private Member Functions
void	init ()
	QFile (const QFile &)
QFile &	operator= (const QFile &)

Private Attributes
QCString	ungetchBuffer

Additional Inherited Members
Protected Member Functions inherited from QIODevice
void	setFlags (int f)
void	setType (int)
void	setMode (int)
void	setState (int)
void	setStatus (int)

Detailed Description

The QFile class is an I/O device that operates on files.

QFile is an I/O device for reading and writing binary and text files. A QFile may be used by itself (readBlock and writeBlock) or by more conveniently using QDataStream or QTextStream.

Here is a code fragment that uses QTextStream to read a text file line by line. It prints each line with a line number.

QFile f("file.txt");
if ( f.open(IO_ReadOnly) ) {    // file opened successfully
    QTextStream t( &f );          // use a text stream
    QString s;
    int n = 1;
    while ( !t.eof() ) {          // until end of file...
        s = t.readLine();         // line of text excluding '\n'
        printf( "%3d: %s\n", n++, (const char *)s );
    }
    f.close();
}

The QFileInfo class holds detailed information about a file, such as access permissions, file dates and file types.

The QDir class manages directories and lists of file names.

See also

QDataStream, QTextStream

Definition at line 50 of file qfile.h.

Member Typedef Documentation

typedef QString(* QFile::DecoderFn) (const QCString &localfileName)

Definition at line 61 of file qfile.h.

typedef QCString(* QFile::EncoderFn) (const QString &fileName)

Definition at line 60 of file qfile.h.

Constructor & Destructor Documentation

QFile::QFile

(

)

Constructs a QFile with no name.

Definition at line 92 of file qfile.cpp.

{
    init();
}

QFile::QFile

(

const QString &

name

)

Constructs a QFile with a file name name.

See also

setName()

Definition at line 102 of file qfile.cpp.

    : fn(name)
{
    init();
}

QFile::~QFile ( )

virtual

Destructs a QFile. Calls close().

Definition at line 113 of file qfile.cpp.

{
    close();
}

QFile::QFile ( const QFile &  )

private

Member Function Documentation

int QFile::at ( ) const

inlinevirtual

Returns the file index.

See also

size()

Reimplemented from QIODevice.

Definition at line 124 of file qfile.h.

{ return ioIndex; }

bool QFile::at ( int  pos )

virtual

Sets the file index to pos. Returns TRUE if successful, otherwise FALSE.

Example:

QFile f( "data.bin" );
f.open( IO_ReadOnly );                        // index set to 0
f.at( 100 );                          // set index to 100
f.at( f.at()+50 );                            // set index to 150
f.at( f.size()-80 );                  // set index to 80 before EOF
f.close();

Warning

The result is undefined if the file was opened using the IO_Append specifier.

See also

size(), open()

Reimplemented from QIODevice.

Definition at line 434 of file qfile_unix.cpp.

{
    if ( !isOpen() ) {
#if defined(CHECK_STATE)
        qWarning( "QFile::at: File is not open" );
#endif
        return FALSE;
    }
    bool ok;
    if ( isRaw() ) {                            // raw file
        pos = (int)LSEEK(fd, pos, SEEK_SET);
        ok = pos != -1;
    } else {                                    // buffered file
        ok = fseek(fh, pos, SEEK_SET) == 0;
    }
    if ( ok )
        ioIndex = pos;
#if defined(CHECK_RANGE)
    else
        qWarning( "QFile::at: Cannot set file position %d", pos );
#endif
    return ok;
}

bool QFile::atEnd ( ) const

virtual

Returns TRUE if the end of file has been reached, otherwise FALSE.

See also

size()

Reimplemented from QIODevice.

Definition at line 239 of file qfile.cpp.

{
    if ( !isOpen() ) {
#if defined(CHECK_STATE)
        qWarning( "QFile::atEnd: File is not open" );
#endif
        return FALSE;
    }
    if ( isDirectAccess() && !isTranslated() ) {
        if ( at() < length )
            return FALSE;
    }
    return QIODevice::atEnd();
}

void QFile::close ( )

virtual

Closes an open file.

The file is not closed if it was opened with an existing file handle. If the existing file handle is a FILE*, the file is flushed. If the existing file handle is an int file descriptor, nothing is done to the file.

Some "write-behind" filesystems may report an unspecified error on closing the file. These errors only indicate that something may have gone wrong since the previous open(). In such a case status() reports IO_UnspecifiedError after close(), otherwise IO_Ok.

See also

open(), flush()

Implements QIODevice.

Definition at line 614 of file qfile_unix.cpp.

{
    bool ok = FALSE;
    if ( isOpen() ) {                           // file is not open
        if ( fh ) {                             // buffered file
            if ( ext_f )
                ok = fflush( fh ) != -1;        // flush instead of closing
            else
                ok = fclose( fh ) != -1;
        } else {                                // raw file
            if ( ext_f )
                ok = TRUE;                      // cannot close
            else
                ok = CLOSE( fd ) != -1;
        }
        init();                                 // restore internal state
    }
    if (!ok)
        setStatus (IO_UnspecifiedError);

    return;
}

QString QFile::decodeName ( const QCString &  localFileName )

static

This does the reverse of QFile::encodeName().

See also

setDecodingFunction()

Definition at line 529 of file qfile.cpp.

{
    return (*decoder)(localFileName);
}

QCString QFile::encodeName ( const QString &  fileName )

static

When you use QFile, QFileInfo, and QDir to access the filesystem with Qt, you can use Unicode filenames. On Unix, these filenames are converted to an 8-bit encoding. If you want to do your own file I/O on Unix, you should convert the filename using this function. On Windows NT, Unicode filenames are supported directly in the filesystem and this function should be avoided. On Windows 95, non-Latin1 locales are not supported at this time.

By default, this function converts to the local 8-bit encoding determined by the user's locale. This is sufficient for filenames that the user chooses. Filenames hard-coded into the application should only use 7-bit ASCII filename characters.

The conversion scheme can be changed using setEncodingFunction(). This might be useful if you wish to give the user an option to store in filenames in UTF-8, etc., but beware that such filenames would probably then be unrecognizable when seen by other programs.

See also

decodeName()

Definition at line 494 of file qfile.cpp.

{
    return (*encoder)(fileName);
}

bool QFile::exists

(

)

const

Returns TRUE if this file exists, otherwise FALSE.

See also

name()

Definition at line 183 of file qfile.cpp.

{
    return qt_file_access( fn, F_OK );
}

bool QFile::exists ( const QString &  fileName )

static

Returns TRUE if the file given by fileName exists, otherwise FALSE.

Definition at line 192 of file qfile.cpp.

{
    return qt_file_access( fileName, F_OK );
}

void QFile::flush ( )

virtual

Flushes the file buffer to the disk.

close() also flushes the file buffer.

Implements QIODevice.

Definition at line 228 of file qfile.cpp.

{
    if ( isOpen() && fh )                       // can only flush open/buffered
        fflush( fh );                           //   file
}

int QFile::getch ( )

virtual

Reads a single byte/character from the file.

Returns the byte/character read, or -1 if the end of the file has been reached.

See also

putch(), ungetch()

Implements QIODevice.

Definition at line 337 of file qfile.cpp.

{
#if defined(CHECK_STATE)
    if ( !isOpen() ) {                          // file not open
        qWarning( "QFile::getch: File not open" );
        return EOF;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QFile::getch: Read operation not permitted" );
        return EOF;
    }
#endif

    int ch;

    if ( !ungetchBuffer.isEmpty() ) {
        int len = ungetchBuffer.length();
        ch = ungetchBuffer[ len-1 ];
        ungetchBuffer.truncate( len - 1 );
        return ch;
    }

    if ( isRaw() ) {                            // raw file (inefficient)
        char buf[1];
        ch = readBlock( buf, 1 ) == 1 ? buf[0] : EOF;
    } else {                                    // buffered file
        if ( (ch = getc( fh )) != EOF )
            ioIndex++;
        else
            setStatus(IO_ReadError);
    }
    return ch;
}

int QFile::handle

(

)

const

Returns the file handle of the file.

This is a small positive integer, suitable for use with C library functions such as fdopen() and fcntl(), as well as with QSocketNotifier.

If the file is not open or there is an error, handle() returns -1.

See also

QSocketNotifier

Definition at line 587 of file qfile_unix.cpp.

{
    if ( !isOpen() )
        return -1;
    else if ( fh )
        return FILENO( fh );
    else
        return fd;
}

void QFile::init ( )

private

Definition at line 124 of file qfile.cpp.

{
    setFlags( IO_Direct );
    setStatus( IO_Ok );
    fh     = 0;
    fd     = 0;
    length = 0;
    ioIndex = 0;
    ext_f  = FALSE;                             // not an external file handle
}

QString QFile::name ( ) const

inline

Returns the name set by setName().

See also

setName(), QFileInfo::fileName()

Definition at line 121 of file qfile.h.

{ return fn; }

bool QFile::open ( int  m )

virtual

Opens the file specified by the file name currently set, using the mode m. Returns TRUE if successful, otherwise FALSE.

The mode parameter m must be a combination of the following flags:

• IO_Raw specified raw (non-buffered) file access.
• IO_ReadOnly opens the file in read-only mode.
• IO_WriteOnly opens the file in write-only mode (and truncates).
• IO_ReadWrite opens the file in read/write mode, equivalent to (IO_ReadOnly|IO_WriteOnly).
• IO_Append opens the file in append mode. This mode is very useful when you want to write something to a log file. The file index is set to the end of the file. Note that the result is undefined if you position the file index manually using at() in append mode.
• IO_Truncate truncates the file.
• IO_Translate enables carriage returns and linefeed translation for text files under MS-DOS, Windows and OS/2.

The raw access mode is best when I/O is block-operated using 4kB block size or greater. Buffered access works better when reading small portions of data at a time.

Important: When working with buffered files, data may not be written to the file at once. Call flush to make sure the data is really written.

Warning

We have experienced problems with some C libraries when a buffered file is opened for both reading and writing. If a read operation takes place immediately after a write operation, the read buffer contains garbage data. Worse, the same garbage is written to the file. Calling flush() before readBlock() solved this problem.

If the file does not exist and IO_WriteOnly or IO_ReadWrite is specified, it is created.

Example:

QFile f1( "/tmp/data.bin" );
QFile f2( "readme.txt" );
f1.open( IO_Raw | IO_ReadWrite | IO_Append );
f2.open( IO_ReadOnly | IO_Translate );

See also

name(), close(), isOpen(), flush()

Implements QIODevice.

Definition at line 134 of file qfile_unix.cpp.

{
    if ( isOpen() ) {                           // file already open
#if defined(CHECK_STATE)
        qWarning( "QFile::open: File already open" );
#endif
        return FALSE;
    }
    if ( fn.isNull() ) {                        // no file name defined
#if defined(CHECK_NULL)
        qWarning( "QFile::open: No file name specified" );
#endif
        return FALSE;
    }
    init();                                     // reset params
    setMode( m );
    if ( !(isReadable() || isWritable()) ) {
#if defined(CHECK_RANGE)
        qWarning( "QFile::open: File access not specified" );
#endif
        return FALSE;
    }
    bool ok = TRUE;
    STATBUF st;
    if ( isRaw() ) {                            // raw file I/O
        int oflags = OPEN_RDONLY;
        if ( isReadable() && isWritable() )
            oflags = OPEN_RDWR;
        else if ( isWritable() )
            oflags = OPEN_WRONLY;
        if ( flags() & IO_Append ) {            // append to end of file?
            if ( flags() & IO_Truncate )
                oflags |= (OPEN_CREAT | OPEN_TRUNC);
            else
                oflags |= (OPEN_APPEND | OPEN_CREAT);
            setFlags( flags() | IO_WriteOnly ); // append implies write
        } else if ( isWritable() ) {            // create/trunc if writable
            if ( flags() & IO_Truncate )
                oflags |= (OPEN_CREAT | OPEN_TRUNC);
            else
                oflags |= OPEN_CREAT;
        }
#if defined(HAS_TEXT_FILEMODE)
        if ( isTranslated() )
#ifdef __CYGWIN__
          /* Do nothing, allowing the Cygwin mount mode to take effect. */;
#else
            oflags |= OPEN_TEXT;
#endif
        else
            oflags |= OPEN_BINARY;
#endif
#if defined(HAS_ASYNC_FILEMODE)
        if ( isAsynchronous() )
            oflags |= OPEN_ASYNC;
#endif
        fd = OPEN( QFile::encodeName(fn), oflags, 0666 );

        if ( fd != -1 ) {                       // open successful
            FSTAT( fd, &st ); // get the stat for later usage
        } else {
            ok = FALSE;
        }
    } else {                                    // buffered file I/O
        QCString perm;
        char perm2[4];
        bool try_create = FALSE;
        if ( flags() & IO_Append ) {            // append to end of file?
            setFlags( flags() | IO_WriteOnly ); // append implies write
            perm = isReadable() ? "a+" : "a";
        } else {
            if ( isReadWrite() ) {
                if ( flags() & IO_Truncate ) {
                    perm = "w+";
                } else {
                    perm = "r+";
                    try_create = TRUE;          // try to create if not exists
                }
            } else if ( isReadable() ) {
                perm = "r";
            } else if ( isWritable() ) {
                perm = "w";
            }
        }
        qstrcpy( perm2, perm );
#if defined(HAS_TEXT_FILEMODE)
        if ( isTranslated() )
#ifdef __CYGWIN__
            /* Do nothing, allowing the Cygwin mount mode to take effect. */;
#else
            strcat( perm2, "t" );
#endif
        else
            strcat( perm2, "b" );
#endif
        while (1) { // At most twice

            fh = fopen( QFile::encodeName(fn), perm2 );

            if ( !fh && try_create ) {
                perm2[0] = 'w';                 // try "w+" instead of "r+"
                try_create = FALSE;
            } else {
                break;
            }
        }
        if ( fh ) {
            FSTAT( FILENO(fh), &st ); // get the stat for later usage
        } else {
            ok = FALSE;
        }
    }
    if ( ok ) {
        setState( IO_Open );
        // on successful open the file stat was got; now test what type
        // of file we have
        if ( (st.st_mode & STAT_MASK) != STAT_REG ) {
            // non-seekable
            setType( IO_Sequential );
            length = INT_MAX;
            ioIndex  = (flags() & IO_Append) == 0 ? 0 : length;
        } else {
            length = (int)st.st_size;
            ioIndex  = (flags() & IO_Append) == 0 ? 0 : length;
            if ( !(flags()&IO_Truncate) && length == 0 && isReadable() ) {
                // try if you can read from it (if you can, it's a sequential
                // device; e.g. a file in the /proc filesystem)
                int c = getch();
                if ( c != -1 ) {
                    ungetch(c);
                    setType( IO_Sequential );
                    length = INT_MAX;
                }
            }
        }
    } else {
        init();
        if ( errno == EMFILE )                  // no more file handles/descrs
            setStatus( IO_ResourceError );
        else
            setStatus( IO_OpenError );
    }
    return ok;
}

bool QFile::open	(	int	m,
		FILE *	f
	)

Opens a file in the mode m using an existing file handle f. Returns TRUE if successful, otherwise FALSE.

Example:

#include <stdio.h>

void printError( const char* msg )
{
    QFile f;
    f.open( IO_WriteOnly, stderr );
    f.writeBlock( msg, qstrlen(msg) );        // write to stderr
    f.close();
}

When a QFile is opened using this function, close() does not actually close the file, only flushes it.

Warning

If f is stdin, stdout, stderr, you may not be able to seek. See QIODevice::isSequentialAccess() for more information.

See also

close()

Definition at line 306 of file qfile_unix.cpp.

{
    if ( isOpen() ) {
#if defined(CHECK_RANGE)
        qWarning( "QFile::open: File already open" );
#endif
        return FALSE;
    }
    init();
    setMode( m &~IO_Raw );
    setState( IO_Open );
    fh = f;
    ext_f = TRUE;
    STATBUF st;
    FSTAT( FILENO(fh), &st );
    ioIndex = (int)ftell( fh );
    if ( (st.st_mode & STAT_MASK) != STAT_REG || f == stdin ) { //stdin is non seekable
        // non-seekable
        setType( IO_Sequential );
        length = INT_MAX;
    } else {
        length = (int)st.st_size;
        if ( !(flags()&IO_Truncate) && length == 0 && isReadable() ) {
            // try if you can read from it (if you can, it's a sequential
            // device; e.g. a file in the /proc filesystem)
            int c = getch();
            if ( c != -1 ) {
                ungetch(c);
                setType( IO_Sequential );
                length = INT_MAX;
            }
        }
    }
    return TRUE;
}

bool QFile::open	(	int	m,
		int	f
	)

Opens a file in the mode m using an existing file descriptor f. Returns TRUE if successful, otherwise FALSE.

When a QFile is opened using this function, close() does not actually close the file.

Warning

If f is one of 0 (stdin), 1 (stdout) or 2 (stderr), you may not be able to seek. size() is set to INT_MAX (in limits.h).

See also

close()

Definition at line 356 of file qfile_unix.cpp.

{
    if ( isOpen() ) {
#if defined(CHECK_RANGE)
        qWarning( "QFile::open: File already open" );
#endif
        return FALSE;
    }
    init();
    setMode( m |IO_Raw );
    setState( IO_Open );
    fd = f;
    ext_f = TRUE;
    STATBUF st;
    FSTAT( fd, &st );
    ioIndex  = (int)LSEEK(fd, 0, SEEK_CUR);
    if ( (st.st_mode & STAT_MASK) != STAT_REG || f == 0 ) { // stdin is not seekable...
        // non-seekable
        setType( IO_Sequential );
        length = INT_MAX;
    } else {
        length = (int)st.st_size;
        if ( length == 0 && isReadable() ) {
            // try if you can read from it (if you can, it's a sequential
            // device; e.g. a file in the /proc filesystem)
            int c = getch();
            if ( c != -1 ) {
                ungetch(c);
                setType( IO_Sequential );
                length = INT_MAX;
            }
            resetStatus();
        }
    }
    return TRUE;
}

QFile& QFile::operator= ( const QFile &  )

private

int64 QFile::pos

(

)

const

Definition at line 637 of file qfile_unix.cpp.

{
  if (isOpen())
  {
    // TODO: support 64 bit size
    return ftell( fh );
  }
  return -1;
}

int QFile::putch ( int  ch )

virtual

Writes the character ch to the file.

Returns ch, or -1 if some error occurred.

See also

getch(), ungetch()

Implements QIODevice.

Definition at line 386 of file qfile.cpp.

{
#if defined(CHECK_STATE)
    if ( !isOpen() ) {                          // file not open
        qWarning( "QFile::putch: File not open" );
        return EOF;
    }
    if ( !isWritable() ) {                      // writing not permitted
        qWarning( "QFile::putch: Write operation not permitted" );
        return EOF;
    }
#endif
    if ( isRaw() ) {                            // raw file (inefficient)
        char buf[1];
        buf[0] = ch;
        ch = writeBlock( buf, 1 ) == 1 ? ch : EOF;
    } else {                                    // buffered file
        if ( (ch = putc( ch, fh )) != EOF ) {
            ioIndex++;
            if ( ioIndex > length )             // update file length
                length = ioIndex;
        } else {
            setStatus(IO_WriteError);
        }
    }
    return ch;
}

int QFile::readBlock ( char *  p, uint  len  )

virtual

Reads at most len bytes from the file into p and returns the number of bytes actually read.

Returns -1 if a serious error occurred.

Warning

We have experienced problems with some C libraries when a buffered file is opened for both reading and writing. If a read operation takes place immediately after a write operation, the read buffer contains garbage data. Worse, the same garbage is written to the file. Calling flush() before readBlock() solved this problem.

See also

writeBlock()

Implements QIODevice.

Definition at line 473 of file qfile_unix.cpp.

{
#if defined(CHECK_NULL)
    if ( !p )
        qWarning( "QFile::readBlock: Null pointer error" );
#endif
#if defined(CHECK_STATE)
    if ( !isOpen() ) {                          // file not open
        qWarning( "QFile::readBlock: File not open" );
        return -1;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QFile::readBlock: Read operation not permitted" );
        return -1;
    }
#endif
    int nread = 0;                                      // number of bytes read
    if ( !ungetchBuffer.isEmpty() ) {
        // need to add these to the returned string.
        int l = ungetchBuffer.length();
        while( nread < l ) {
            *p = ungetchBuffer[ l - nread - 1 ];
            p++;
            nread++;
        }
        ungetchBuffer.truncate( l - nread );
    }
    
    if ( nread < (int)len ) {
        if ( isRaw() ) {                                // raw file
            nread += (int)READ( fd, p, len-nread );
            if ( len && nread <= 0 ) {
                nread = 0;
                setStatus(IO_ReadError);
            }
        } else {                                        // buffered file
            nread += (int)fread( p, 1, len-nread, fh );
            if ( (uint)nread != len ) {
                if ( ferror( fh ) || nread==0 )
                    setStatus(IO_ReadError);
            }
        }
    }
    ioIndex += nread;
    return nread;
}

int QFile::readLine ( char *  p, uint  maxlen  )

virtual

Reads a line of text.

Reads bytes from the file until end-of-line is reached, or up to maxlen bytes, and returns the number of bytes read, or -1 in case of error. The terminating newline is not stripped.

This function is efficient only for buffered files. Avoid readLine() for files that have been opened with the IO_Raw flag.

See also

readBlock(), QTextStream::readLine()

Reimplemented from QIODevice.

Definition at line 268 of file qfile.cpp.

{
    if ( maxlen == 0 )                          // application bug?
        return 0;
#if defined(CHECK_STATE)
    CHECK_PTR( p );
    if ( !isOpen() ) {                          // file not open
        qWarning( "QFile::readLine: File not open" );
        return -1;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QFile::readLine: Read operation not permitted" );
        return -1;
    }
#endif
    int nread;                                  // number of bytes read
    if ( isRaw() ) {                            // raw file
        nread = QIODevice::readLine( p, maxlen );
    } else {                                    // buffered file
        p = fgets( p, maxlen, fh );
        if ( p ) {
            nread = qstrlen( p );
            ioIndex += nread;
        } else {
            nread = -1;
            setStatus(IO_ReadError);
        }
    }
    return nread;
}

int QFile::readLine	(	QString &	s,
		uint	maxlen
	)

Reads a line of text.

Reads bytes from the file until end-of-line is reached, or up to maxlen bytes, and returns the number of bytes read, or -1 in case of error. The terminating newline is not stripped.

This function is efficient only for buffered files. Avoid readLine() for files that have been opened with the IO_Raw flag.

Note that the string is read as plain Latin1 bytes, not Unicode.

See also

readBlock(), QTextStream::readLine()

Definition at line 316 of file qfile.cpp.

{
    QByteArray ba(maxlen);
    int l = readLine(ba.data(),maxlen);
    if ( l >= 0 ) {
        ba.truncate(l);
        s = QString(ba);
    }
    return l;
}

bool QFile::remove

(

)

Removes the file specified by the file name currently set. Returns TRUE if successful, otherwise FALSE.

The file is closed before it is removed.

Definition at line 205 of file qfile.cpp.

{
    close();
    return remove( fn );
}

bool QFile::remove ( const QString &  fileName )

static

Removes the file fileName. Returns TRUE if successful, otherwise FALSE.

Definition at line 66 of file qfile_unix.cpp.

{
    if ( fileName.isEmpty() ) {
#if defined(CHECK_NULL)
        qWarning( "QFile::remove: Empty or null file name" );
#endif
        return FALSE;
    }
    return unlink( QFile::encodeName(fileName) ) == 0;  
    // unlink more common in UNIX
}

bool QFile::seek

(

int64

pos

)

Definition at line 660 of file qfile_unix.cpp.

{
  if (isOpen())
  {
    // TODO: support 64 bit size
    return fseek( fh, (long)pos, SEEK_SET )!=-1;
  }
  return FALSE;
}

void QFile::setDecodingFunction ( DecoderFn  f )

static

Sets the function for decoding 8-bit filenames. The default uses the locale-specific 8-bit encoding.

See also

encodeName(), decodeName()

Definition at line 547 of file qfile.cpp.

{
    decoder = f;
}

void QFile::setEncodingFunction ( EncoderFn  f )

static

Sets the function for encoding Unicode filenames. The default encodes in the locale-specific 8-bit encoding.

See also

encodeName()

Definition at line 511 of file qfile.cpp.

{
    encoder = f;
}

void QFile::setName

(

const QString &

name

)

Sets the name of the file. The name can include an absolute directory path or it can be a name or a path relative to the current directory.

Do not call this function if the file has already been opened.

Note that if the name is relative QFile does not associate it with the current directory. If you change directory before calling open(), open uses the new current directory.

Example:

QFile f;
QDir::setCurrent( "/tmp" );
f.setName( "readme.txt" );
QDir::setCurrent( "/home" );
f.open( IO_ReadOnly );          // opens "/home/readme.txt" under UNIX

Also note that the directory separator '/' works for all operating systems supported by Qt.

See also

name(), QFileInfo, QDir

Definition at line 167 of file qfile.cpp.

{
    if ( isOpen() ) {
#if defined(CHECK_STATE)
        qWarning( "QFile::setName: File is open" );
#endif
        close();
    }
    fn = name;
}

uint QFile::size ( ) const

virtual

Returns the file size.

See also

at()

Implements QIODevice.

Definition at line 398 of file qfile_unix.cpp.

{
    STATBUF st;
    if ( isOpen() ) {
        FSTAT( fh ? FILENO(fh) : fd, &st );
    } else {
        STAT( QFile::encodeName(fn), &st );
    }
    return (uint)st.st_size;
}

int64 QFile::toEnd

(

)

Definition at line 647 of file qfile_unix.cpp.

{
  if (isOpen())
  {
     // TODO: support 64 bit size
     if (fseek( fh, 0, SEEK_END )!=-1)
     {
       return ftell( fh );
     }
  }
  return -1;
}

int QFile::ungetch ( int  ch )

virtual

Puts the character ch back into the file and decrements the index if it is not zero.

This function is normally called to "undo" a getch() operation.

Returns ch, or -1 if some error occurred.

See also

getch(), putch()

Implements QIODevice.

Definition at line 425 of file qfile.cpp.

{
#if defined(CHECK_STATE)
    if ( !isOpen() ) {                          // file not open
        qWarning( "QFile::ungetch: File not open" );
        return EOF;
    }
    if ( !isReadable() ) {                      // reading not permitted
        qWarning( "QFile::ungetch: Read operation not permitted" );
        return EOF;
    }
#endif
    if ( ch == EOF )                            // cannot unget EOF
        return ch;

    if ( isSequentialAccess() && !fh) {
        // pipe or similar => we cannot ungetch, so do it manually
        ungetchBuffer +=ch;
        return ch;
    }

    if ( isRaw() ) {                            // raw file (very inefficient)
        char buf[1];
        at( ioIndex-1 );
        buf[0] = ch;
        if ( writeBlock(buf, 1) == 1 )
            at ( ioIndex-1 );
        else
            ch = EOF;
    } else {                                    // buffered file
        if ( (ch = ungetc(ch, fh)) != EOF )
            ioIndex--;
        else
            setStatus( IO_ReadError );
    }
    return ch;
}

int QFile::writeBlock ( const char *  p, uint  len  )

virtual

Writes len bytes from p to the file and returns the number of bytes actually written.

Returns -1 if a serious error occurred.

Warning

When working with buffered files, data may not be written to the file at once. Call flush() to make sure the data is really written.

See also

readBlock()

Implements QIODevice.

Definition at line 537 of file qfile_unix.cpp.

{
#if defined(CHECK_NULL)
    if ( p == 0 && len != 0 )
        qWarning( "QFile::writeBlock: Null pointer error" );
#endif
#if defined(CHECK_STATE)
    if ( !isOpen() ) {                          // file not open
        qWarning( "QFile::writeBlock: File not open" );
        return -1;
    }
    if ( !isWritable() ) {                      // writing not permitted
        qWarning( "QFile::writeBlock: Write operation not permitted" );
        return -1;
    }
#endif
    if (p==0) return 0;
    int nwritten;                               // number of bytes written
    if ( isRaw() )                              // raw file
        nwritten = (int)WRITE( fd, p, len );
    else                                        // buffered file
        nwritten = (int)fwrite( p, 1, len, fh );
    if ( nwritten != (int)len ) {               // write error
        if ( errno == ENOSPC )                  // disk is full
            setStatus( IO_ResourceError );
        else
            setStatus( IO_WriteError );
        if ( isRaw() )                          // recalc file position
            ioIndex = (int)LSEEK( fd, 0, SEEK_CUR );
        else
            ioIndex = fseek( fh, 0, SEEK_CUR );
    } else {
        ioIndex += nwritten;
    }
    if ( ioIndex > length )                     // update file length
        length = ioIndex;
    return nwritten;
}

int QFile::writeBlock ( const QByteArray &  data )

inline

Definition at line 86 of file qfile.h.

                    { return QIODevice::writeBlock(data); }

Member Data Documentation

void* QFile::d

protected

Definition at line 107 of file qfile.h.

bool QFile::ext_f

protected

Definition at line 106 of file qfile.h.

int QFile::fd

protected

Definition at line 104 of file qfile.h.

FILE* QFile::fh

protected

Definition at line 103 of file qfile.h.

QString QFile::fn

protected

Definition at line 102 of file qfile.h.

int QFile::length

protected

Definition at line 105 of file qfile.h.

QCString QFile::ungetchBuffer

private

Definition at line 111 of file qfile.h.

---

The documentation for this class was generated from the following files:

• doxygen-1.8.11/qtools/qfile.h
• doxygen-1.8.11/qtools/qfile.cpp
• doxygen-1.8.11/qtools/qfile_unix.cpp
• doxygen-1.8.11/qtools/qfile_win32.cpp