qbuffer.3qt

tmark1.11:用于生成QT/EMBEDDED应用工程的Markfile文件

.TH QBuffer 3qt "6 July 1999" "Troll Tech AS" \" -*- nroff -*-
.\" Copyright 1992-1999 Troll Tech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QBuffer \- I/O device that operates on a QByteArray
.SH SYNOPSIS
.br
.PP
\fC#include <qbuffer.h>\fR
.PP
Inherits QIODevice.
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "\fBQBuffer\fR ()"
.br
.ti -1c
.BI "\fBQBuffer\fR ( QByteArray )"
.br
.ti -1c
.BI "\fB~QBuffer\fR ()"
.br
.ti -1c
.BI "QByteArray \fBbuffer\fR () const"
.br
.ti -1c
.BI "bool \fBsetBuffer\fR ( QByteArray )"
.br
.ti -1c
.BI "virtual bool \fBopen\fR ( int )"
.br
.ti -1c
.BI "virtual void \fBclose\fR ()"
.br
.ti -1c
.BI "virtual void \fBflush\fR ()"
.br
.ti -1c
.BI "virtual uint \fBsize\fR () const"
.br
.ti -1c
.BI "virtual int \fBat\fR () const"
.br
.ti -1c
.BI "virtual bool \fBat\fR ( int )"
.br
.ti -1c
.BI "virtual int \fBreadBlock\fR ( char * " "p" ", uint )"
.br
.ti -1c
.BI "virtual int \fBwriteBlock\fR ( const char * " "p" ", uint )"
.br
.ti -1c
.BI "virtual int \fBreadLine\fR ( char * " "p" ", uint )"
.br
.ti -1c
.BI "virtual int \fBgetch\fR ()"
.br
.ti -1c
.BI "virtual int \fBputch\fR ( int )"
.br
.ti -1c
.BI "virtual int \fBungetch\fR ( int )"
.br
.in -1c
.SH DESCRIPTION
The QBuffer class is an I/O device that operates on a QByteArray
.PP
QBuffer is an I/O device for reading and writing a memory buffer. A QBuffer may be used directly (readBlock() and writeBlock()) or more conveniently via QDataStream or QTextStream. Most of its behavior is inherited from QIODevice.
.PP
A QBuffer has an associated QByteArray which holds the buffer data. Writing data at the end (i.e. size()) of the buffer expands the byte array.
.PP
For convenience, the byte stream classes QDataStream and QTextStream can operate on a QByteArray (or a QString) via an internal QBuffer:
.PP
.nf
.br
    QString str;
.br
    QTextStream ts( str, IO_WriteOnly );
.br
    ts << "pi = " << 3.14;                      // str == "pi = 3.14"
.fi
.PP
See also: QFile, QDataStream and QTextStream.
.PP
Examples:
.(l
grapher/grapher.cpp
.)l
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QBuffer::QBuffer ()"
Constructs an empty buffer.
.SH "QBuffer::QBuffer ( QByteArray buf )"
Constructs a buffer and sets the buffer contents to \fIbuf.\fR
.PP
See also: setBuffer().
.SH "QBuffer::~QBuffer ()"
Destroys the buffer.
.SH "bool QBuffer::at ( int pos ) \fC[virtual]\fR"
Sets the buffer index to \fIpos.\fR Returns TRUE if successful, otherwise FALSE.
.PP
See also: size().
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::at () const \fC[virtual]\fR"
Returns the buffer index.
.PP
See also: size().
.PP
Reimplemented from QIODevice.
.SH "QByteArray QBuffer::buffer () const"
Returns the buffer most recently set by setBuffer(), or at construction.
.SH "void QBuffer::close () \fC[virtual]\fR"
Closes an open buffer.
.PP
See also: open().
.PP
Examples:
.(l
grapher/grapher.cpp
.)l
.PP
Reimplemented from QIODevice.
.SH "void QBuffer::flush () \fC[virtual]\fR"
The flush function does nothing.
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::getch () \fC[virtual]\fR"
Reads a single byte/character from the buffer.
.PP
Returns the byte/character read, or -1 if the end of the buffer has been reached.
.PP
See also: putch() and ungetch().
.PP
Reimplemented from QIODevice.
.SH "bool QBuffer::open ( int m ) \fC[virtual]\fR"
Opens the file specified by the file name currently set, using the mode \fIm.\fR Returns TRUE if successful, otherwise FALSE.
.PP
The mode parameter \fIm\fR must be a combination of the following flags.
.TP
\fCIO_ReadOnly\fR opens a buffer in read-only mode.
.TP
\fCIO_WriteOnly\fR opens a buffer in write-only mode.
.TP
\fCIO_ReadWrite\fR opens a buffer in read/write mode.
.TP
\fCIO_Append\fR sets the buffer index to the end of the buffer.
.TP
\fCIO_Truncate\fR truncates the buffer.
.PP
See also: close() and isOpen().
.PP
Examples:
.(l
grapher/grapher.cpp
.)l
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::putch ( int ch ) \fC[virtual]\fR"
Writes the character \fIch\fR into the buffer, overwriting the character at the current index, extending the buffer if necessary.
.PP
Returns \fIch,\fR or -1 if some error occurred.
.PP
See also: getch() and ungetch().
.PP
Examples:
.(l
grapher/grapher.cpp
.)l
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::readBlock ( char * p, uint len ) \fC[virtual]\fR"
Reads at most \fIlen\fR bytes from the buffer into \fIp\fR and returns the number of bytes actually read.
.PP
Returns -1 if a serious error occurred.
.PP
See also: writeBlock().
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::readLine ( char * p, uint maxlen ) \fC[virtual]\fR"
Reads a line of text.
.PP
Reads bytes from the buffer until end-of-line is reached, or up to \fImaxlen\fR bytes.
.PP
See also: readBlock().
.PP
Reimplemented from QIODevice.
.SH "bool QBuffer::setBuffer ( QByteArray buf )"
Replaces the buffer's contents with \fIbuf.\fR
.PP
This may not be done while the buffer is open.
.PP
Note that if you open the buffer in write mode (\fCIO_WriteOnly\fR or IO_ReadWrite) and write something into the buffer, \fIbuf\fR is also modified because QByteArray is an explicitly shared class.
.PP
Example:
.PP
.nf
.br
    QString str = "abc";
.br
    QBuffer b( str );
.br
    b.open( IO_WriteOnly );
.br
    b.at( 3 );                                  // position at \\0
.br
    b.writeBlock( "def", 4 );                   // write including \\0
.br
    b.close();
.br
      // Now, str == "abcdef"
.fi
.PP
See also: open and Shared Classes
.SH "uint QBuffer::size () const \fC[virtual]\fR"
Returns the number of bytes in the buffer.
.PP
See also: at().
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::ungetch ( int ch ) \fC[virtual]\fR"
Puts the character \fIch\fR back into the buffer and decrements the index if it is not zero.
.PP
This function is normally called to "undo" a getch() operation.
.PP
Returns \fIch,\fR or -1 if some error occurred.
.PP
See also: getch() and putch().
.PP
Reimplemented from QIODevice.
.SH "int QBuffer::writeBlock ( const char * p, uint len ) \fC[virtual]\fR"
Writes \fIlen\fR bytes from \fIp\fR into the buffer at the current index, overwriting any characters there and extending the buffer if necessary. Returns the number of bytes actually written.
.PP
Returns -1 if a serious error occurred.
.PP
See also: readBlock().
.PP
Reimplemented from QIODevice.
.SH "SEE ALSO"
.BR http://www.troll.no/qt/qbuffer.html
.SH COPYRIGHT
Copyright 1992-1999 Troll Tech AS.  See the license file included in
the distribution for a complete license statement.
.SH AUTHOR
Generated automatically from the source code.