qfile.cpp

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	return -1;
    }
#endif
    Q_LONG 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 );
	    if ( !isSequentialAccess() )
		ioIndex += nread;
	} else {
	    nread = -1;
	    setStatus(IO_ReadError);
	    setErrorString( qt_fileerr_read );
	}
    }
    return nread;
}


/*!
    \overload

    Reads a line of text.

    Reads bytes from the file into string \a s, until end-of-line or
    \a maxlen bytes have been read, whichever occurs first. Returns
    the number of bytes read, or -1 if there was an error, e.g. end of
    file. Any terminating newline is not stripped.

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

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

    \sa readBlock(), QTextStream::readLine()
*/

Q_LONG QFile::readLine( QString& s, Q_ULONG maxlen )
{
    QByteArray ba(maxlen);
    Q_LONG l = readLine(ba.data(),maxlen);
    if ( l >= 0 ) {
	ba.truncate(l);
	s = QString(ba);
    }
    return l;
}


/*!
    Reads a single byte/character from the file.

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

    \sa putch(), ungetch()
*/

int QFile::getch()
{
#if defined(QT_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 ) {
	    if ( !isSequentialAccess() )
		ioIndex++;
	} else {
	    setStatus(IO_ReadError);
	    setErrorString( qt_fileerr_read );
	}
    }
    return ch;
}

/*!
    Writes the character \a ch to the file.

    Returns \a ch, or -1 if some error occurred.

    \sa getch(), ungetch()
*/

int QFile::putch( int ch )
{
#if defined(QT_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 ) {
	    if ( !isSequentialAccess() )
		ioIndex++;
	    if ( ioIndex > length )		// update file length
		length = ioIndex;
	} else {
	    setStatus(IO_WriteError);
	    setErrorString( qt_fileerr_write );
	}
    }
    return ch;
}

/*!
    Puts the character \a 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 \a ch, or -1 if an error occurred.

    \sa getch(), putch()
*/

int QFile::ungetch( int ch )
{
#if defined(QT_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 ) {
	    if ( !isSequentialAccess() )
		ioIndex--;
	} else {
	    setStatus( IO_ReadError );
	    setErrorString( qt_fileerr_read );
	}
    }
    return ch;
}


static QCString locale_encoder( const QString &fileName )
{
    return fileName.local8Bit();
}


static QFile::EncoderFn encoder = locale_encoder;

/*!
    When you use QFile, QFileInfo, and QDir to access the file system
    with Qt, you can use Unicode file names. On Unix, these file names
    are converted to an 8-bit encoding. If you want to do your own
    file I/O on Unix, you should convert the file name using this
    function. On Windows NT/2000, Unicode file names are supported
    directly in the file system and this function should be avoided.
    On Windows 95, non-Latin1 locales are not supported.

    By default, this function converts \a fileName to the local 8-bit
    encoding determined by the user's locale. This is sufficient for
    file names that the user chooses. File names 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 file names in UTF-8, etc., but be aware that such file names
    would probably then be unrecognizable when seen by other programs.

    \sa decodeName()
*/

QCString QFile::encodeName( const QString &fileName )
{
    return (*encoder)(fileName);
}

/*!
    \enum QFile::EncoderFn

    This is used by QFile::setEncodingFunction().
*/

/*!
    \nonreentrant

    Sets the function for encoding Unicode file names to \a f. The
    default encodes in the locale-specific 8-bit encoding.

    \sa encodeName()
*/
void QFile::setEncodingFunction( EncoderFn f )
{
    encoder = f;
}

static
QString locale_decoder( const QCString &localFileName )
{
    return QString::fromLocal8Bit(localFileName);
}

static QFile::DecoderFn decoder = locale_decoder;

/*!
    This does the reverse of QFile::encodeName() using \a localFileName.

    \sa setDecodingFunction()
*/
QString QFile::decodeName( const QCString &localFileName )
{
    return (*decoder)(localFileName);
}

/*!
    \enum QFile::DecoderFn

    This is used by QFile::setDecodingFunction().
*/

/*!
    \nonreentrant

    Sets the function for decoding 8-bit file names to \a f. The
    default uses the locale-specific 8-bit encoding.

    \sa encodeName(), decodeName()
*/

void QFile::setDecodingFunction( DecoderFn f )
{
    decoder = f;
}

/*!
    Returns a human readable description of the reason of an error that occured
    on the device. The error described by the string corresponds to changes of
    QIODevice::status(). If the status is reset, the error string is also reset.

    The returned strings are not translated with the QObject::tr() or
    QApplication::translate() functions. They are marked as translatable
    strings in the context \c QFile. Before you show the string to the user you
    should translate it first, e.g:

    \code
	QFile f( "foo.txt" );
	if ( !f.open( IO_ReadOnly ) {
	    QMessageBox::critical(
		this,
		tr("Open failed"),
		tr("Could not open file for reading: %1").arg( qApp->translate("QFile",f.errorString()) )
		);
	    return;
	}
    \endcode

    \sa QIODevice::status(), QIODevice::resetStatus(), setErrorString()
*/

QString	QFile::errorString() const
{
    if ( status() == IO_Ok )
	return qt_fileerr_unknown;
    return d->errorString;
}

/*!
    \nonreentrant

    Sets the error string returned by the errorString() function to \a str.

    \sa errorString(), QIODevice::status()
*/

void QFile::setErrorString( const QString& str )
{
    d->errorString = str;
}

void QFile::setErrorStringErrno( int errnum )
{
    switch ( errnum ) {
	case EACCES:
	    d->errorString = QFILEERR_EACCES;
	    break;
	case EMFILE:
	    d->errorString = QFILEERR_EMFILE;
	    break;
	case ENOENT:
	    d->errorString = QFILEERR_ENOENT;
	    break;
	case ENOSPC:
	    d->errorString = QFILEERR_ENOSPC;
	    break;
	default:
#ifndef Q_OS_TEMP
	    d->errorString = QString::fromLocal8Bit( strerror( errnum ) );
#else
	    {
		unsigned short *string;
		FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM,
			       NULL,
			       errnum,
			       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
			       (LPTSTR)&string,
			       0,
			       NULL );
		d->errorString = QString::fromUcs2( string );
	        LocalFree( (HLOCAL)string );
	    }
#endif
	    break;
    }
}