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139 lines
5.1 KiB
139 lines
5.1 KiB
13 years ago
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'\" t
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.TH QBuffer 3qt "2 February 2007" "Trolltech AS" \" -*- nroff -*-
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.\" Copyright 1992-2007 Trolltech ASA. All rights reserved. See the
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.\" license file included in the distribution for a complete license
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.\" statement.
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.\"
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.ad l
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.nh
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.SH NAME
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QBuffer \- I/O device that operates on a QByteArray
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.SH SYNOPSIS
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All the functions in this class are reentrant when Qt is built with thread support.</p>
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.PP
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\fC#include <ntqbuffer.h>\fR
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.PP
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Inherits QIODevice.
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.PP
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.SS "Public Members"
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.in +1c
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.ti -1c
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.BI "\fBQBuffer\fR ()"
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.br
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.ti -1c
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.BI "\fBQBuffer\fR ( QByteArray buf )"
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.br
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.ti -1c
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.BI "\fB~QBuffer\fR ()"
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.br
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.ti -1c
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.BI "QByteArray \fBbuffer\fR () const"
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.br
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.ti -1c
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.BI "bool \fBsetBuffer\fR ( QByteArray buf )"
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.br
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.ti -1c
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.BI "virtual TQ_LONG \fBwriteBlock\fR ( const char * p, TQ_ULONG len )"
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.br
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.ti -1c
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.BI "TQ_LONG \fBwriteBlock\fR ( const QByteArray & data )"
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.br
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.in -1c
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.SH DESCRIPTION
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The QBuffer class is an I/O device that operates on a QByteArray.
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.PP
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QBuffer is used to read and write to a memory buffer. It is normally used with a QTextStream or a QDataStream. QBuffer has an associated QByteArray which holds the buffer data. The size() of the buffer is automatically adjusted as data is written.
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.PP
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The constructor \fCQBuffer(QByteArray)\fR creates a QBuffer using an existing byte array. The byte array can also be set with setBuffer(). Writing to the QBuffer will modify the original byte array because QByteArray is explicitly shared.
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.PP
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Use open() to open the buffer before use and to set the mode (read-only, write-only, etc.). close() closes the buffer. The buffer must be closed before reopening or calling setBuffer().
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.PP
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A common way to use QBuffer is through QDataStream or QTextStream, which have constructors that take a QBuffer parameter. For convenience, there are also QDataStream and QTextStream constructors that take a QByteArray parameter. These constructors create and open an internal QBuffer.
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.PP
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Note that QTextStream can also operate on a QString (a Unicode string); a QBuffer cannot.
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.PP
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You can also use QBuffer directly through the standard QIODevice functions readBlock(), writeBlock() readLine(), at(), getch(), putch() and ungetch().
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.PP
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See also QFile, QDataStream, QTextStream, QByteArray, Shared Classes, Collection Classes, and Input/Output and Networking.
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.SH MEMBER FUNCTION DOCUMENTATION
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.SH "QBuffer::QBuffer ()"
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Constructs an empty buffer.
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.SH "QBuffer::QBuffer ( QByteArray buf )"
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Constructs a buffer that operates on \fIbuf\fR.
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.PP
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If you open the buffer in write mode (<a href="ntqfile.html#open">IO_WriteOnly</a> or IO_ReadWrite) and write something into the buffer, \fIbuf\fR will be modified.
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.PP
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Example:
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.PP
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.nf
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.br
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QCString str = "abc";
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.br
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QBuffer b( str );
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.br
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b.open( IO_WriteOnly );
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.br
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b.at( 3 ); // position at the 4th character (the terminating \\0)
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.br
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b.writeBlock( "def", 4 ); // write "def" including the terminating \\0
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.br
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b.close();
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.br
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// Now, str == "abcdef" with a terminating \\0
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.br
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.fi
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.PP
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See also setBuffer().
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.SH "QBuffer::~QBuffer ()"
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Destroys the buffer.
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.SH "QByteArray QBuffer::buffer () const"
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Returns this buffer's byte array.
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.PP
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See also setBuffer().
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.SH "bool QBuffer::setBuffer ( QByteArray buf )"
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Replaces the buffer's contents with \fIbuf\fR and returns TRUE.
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.PP
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Does nothing (and returns FALSE) if isOpen() is TRUE.
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.PP
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Note that if you open the buffer in write mode (<a href="ntqfile.html#open">IO_WriteOnly</a> or IO_ReadWrite) and write something into the buffer, \fIbuf\fR is also modified because QByteArray is an explicitly shared class.
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.PP
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See also buffer(), open(), and close().
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.SH "TQ_LONG QBuffer::writeBlock ( const char * p, TQ_ULONG len )\fC [virtual]\fR"
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Writes \fIlen\fR bytes from \fIp\fR into the buffer at the current index position, overwriting any characters there and extending the buffer if necessary. Returns the number of bytes actually written.
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.PP
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Returns -1 if an error occurred.
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.PP
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See also readBlock().
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.PP
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Reimplemented from QIODevice.
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.SH "TQ_LONG QBuffer::writeBlock ( const QByteArray & data )"
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This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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.PP
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This convenience function is the same as calling
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\fCwriteBlock( data.data(), data.size() )\fR with \fIdata\fR.
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.SH "SEE ALSO"
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.BR http://doc.trolltech.com/ntqbuffer.html
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.BR http://www.trolltech.com/faq/tech.html
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.SH COPYRIGHT
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Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
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license file included in the distribution for a complete license
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statement.
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.SH AUTHOR
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Generated automatically from the source code.
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.SH BUGS
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If you find a bug in Qt, please report it as described in
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.BR http://doc.trolltech.com/bughowto.html .
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Good bug reports help us to help you. Thank you.
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.P
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The definitive Qt documentation is provided in HTML format; it is
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located at $QTDIR/doc/html and can be read using Qt Assistant or with
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a web browser. This man page is provided as a convenience for those
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users who prefer man pages, although this format is not officially
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supported by Trolltech.
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.P
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If you find errors in this manual page, please report them to
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.BR qt-bugs@trolltech.com .
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11 years ago
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Please include the name of the manual page (tqbuffer.3qt) and the Qt
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13 years ago
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version (3.3.8).
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