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< td align = "right" valign = "center" > < img src = "logo32.png" align = "right" width = "64" height = "32" border = "0" > < / td > < / tr > < / table > < h1 align = center > TQBuffer Class Reference< / h1 >
< p > The TQBuffer class is an I/O device that operates on a TQByteArray.
< a href = "#details" > More...< / a >
< p > All the functions in this class are < a href = "threads.html#reentrant" > reentrant< / a > when TQt is built with thread support.< / p >
< p > < tt > #include < < a href = "qbuffer-h.html" > ntqbuffer.h< / a > > < / tt >
< p > Inherits < a href = "ntqiodevice.html" > TQIODevice< / a > .
< p > < a href = "qbuffer-members.html" > List of all member functions.< / a >
< h2 > Public Members< / h2 >
< ul >
< li class = fn > < a href = "#TQBuffer" > < b > TQBuffer< / b > < / a > ()< / li >
< li class = fn > < a href = "#TQBuffer-2" > < b > TQBuffer< / b > < / a > ( TQByteArray buf )< / li >
< li class = fn > < a href = "#~TQBuffer" > < b > ~TQBuffer< / b > < / a > ()< / li >
< li class = fn > TQByteArray < a href = "#buffer" > < b > buffer< / b > < / a > () const< / li >
< li class = fn > bool < a href = "#setBuffer" > < b > setBuffer< / b > < / a > ( TQByteArray buf )< / li >
< li class = fn > virtual TQ_LONG < a href = "#writeBlock" > < b > writeBlock< / b > < / a > ( const char * p, TQ_ULONG len )< / li >
< li class = fn > TQ_LONG < a href = "#writeBlock-2" > < b > writeBlock< / b > < / a > ( const TQByteArray & data )< / li >
< / ul >
< hr > < a name = "details" > < / a > < h2 > Detailed Description< / h2 >
The TQBuffer class is an I/O device that operates on a < a href = "qbytearray.html" > TQByteArray< / a > .
< p >
< p > TQBuffer is used to read and write to a memory buffer. It is
normally used with a < a href = "ntqtextstream.html" > TQTextStream< / a > or a < a href = "ntqdatastream.html" > TQDataStream< / a > . TQBuffer has an
associated TQByteArray which holds the buffer data. The < a href = "ntqiodevice.html#size" > size< / a > () of
the buffer is automatically adjusted as data is written.
< p > The constructor < tt > TQBuffer(TQByteArray)< / tt > creates a TQBuffer using an
existing byte array. The byte array can also be set with
< a href = "#setBuffer" > setBuffer< / a > (). Writing to the TQBuffer will modify the original byte
array because TQByteArray is < a href = "shclass.html" > explicitly
shared.< / a >
< p > Use < a href = "ntqiodevice.html#open" > open< / a > () to open the buffer before use and to set the mode
(read-only, write-only, etc.). < a href = "ntqiodevice.html#close" > close< / a > () closes the buffer. The
buffer must be closed before reopening or calling setBuffer().
< p > A common way to use TQBuffer is through < a href = "ntqdatastream.html" > TQDataStream< / a > or < a href = "ntqtextstream.html" > TQTextStream< / a > , which have constructors that take a TQBuffer
parameter. For convenience, there are also TQDataStream and
< a href = "ntqtextstream.html" > TQTextStream< / a > constructors that take a < a href = "qbytearray.html" > TQByteArray< / a > parameter. These
constructors create and open an internal TQBuffer.
< p > Note that TQTextStream can also operate on a < a href = "ntqstring.html" > TQString< / a > (a Unicode
string); a TQBuffer cannot.
< p > You can also use TQBuffer directly through the standard < a href = "ntqiodevice.html" > TQIODevice< / a >
functions < a href = "ntqiodevice.html#readBlock" > readBlock< / a > (), < a href = "#writeBlock" > writeBlock< / a > () < a href = "ntqiodevice.html#readLine" > readLine< / a > (), < a href = "ntqiodevice.html#at" > at< / a > (), < a href = "ntqiodevice.html#getch" > getch< / a > (),
< a href = "ntqiodevice.html#putch" > putch< / a > () and < a href = "ntqiodevice.html#ungetch" > ungetch< / a > ().
< p > < p > See also < a href = "ntqfile.html" > TQFile< / a > , < a href = "ntqdatastream.html" > TQDataStream< / a > , < a href = "ntqtextstream.html" > TQTextStream< / a > , < a href = "qbytearray.html" > TQByteArray< / a > , < a href = "shclass.html" > Shared Classes< / a > , < a href = "collection.html" > Collection Classes< / a > , and < a href = "io.html" > Input/Output and Networking< / a > .
< hr > < h2 > Member Function Documentation< / h2 >
< h3 class = fn > < a name = "TQBuffer" > < / a > TQBuffer::TQBuffer ()
< / h3 >
Constructs an empty buffer.
< h3 class = fn > < a name = "TQBuffer-2" > < / a > TQBuffer::TQBuffer ( < a href = "qbytearray.html" > TQByteArray< / a > buf )
< / h3 >
Constructs a buffer that operates on < em > buf< / em > .
< p > If you open the buffer in write mode (< a href = "ntqfile.html#open" > < a href = "ntqfile.html#open" > IO_WriteOnly< / a > < / a > or
< a href = "ntqfile.html#open" > IO_ReadWrite< / a > ) and write something into the buffer, < em > buf< / em >
will be modified.
< p > Example:
< pre >
< a href = "ntqcstring.html" > TQCString< / a > str = "abc";
TQBuffer b( str );
b.< a href = "ntqiodevice.html#open" > open< / a > ( IO_WriteOnly );
b.< a href = "ntqiodevice.html#at" > at< / a > ( 3 ); // position at the 4th character (the terminating \0)
b.< a href = "#writeBlock" > writeBlock< / a > ( "def", 4 ); // write "def" including the terminating \0
b.< a href = "ntqiodevice.html#close" > close< / a > ();
// Now, str == "abcdef" with a terminating \0
< / pre >
< p > < p > See also < a href = "#setBuffer" > setBuffer< / a > ().
< h3 class = fn > < a name = "~TQBuffer" > < / a > TQBuffer::~TQBuffer ()
< / h3 >
Destroys the buffer.
< h3 class = fn > < a href = "qbytearray.html" > TQByteArray< / a > < a name = "buffer" > < / a > TQBuffer::buffer () const
< / h3 >
< p > Returns this buffer's byte array.
< p > < p > See also < a href = "#setBuffer" > setBuffer< / a > ().
< h3 class = fn > bool < a name = "setBuffer" > < / a > TQBuffer::setBuffer ( < a href = "qbytearray.html" > TQByteArray< / a > buf )
< / h3 >
Replaces the buffer's contents with < em > buf< / em > and returns TRUE.
< p > Does nothing (and returns FALSE) if < a href = "ntqiodevice.html#isOpen" > isOpen< / a > () is TRUE.
< p > Note that if you open the buffer in write mode (< a href = "ntqfile.html#open" > < a href = "ntqfile.html#open" > IO_WriteOnly< / a > < / a > or
< a href = "ntqfile.html#open" > IO_ReadWrite< / a > ) and write something into the buffer, < em > buf< / em > is also
modified because < a href = "qbytearray.html" > TQByteArray< / a > is an < a href = "shclass.html#explicitly-shared" > explicitly shared< / a > class.
< p > < p > See also < a href = "#buffer" > buffer< / a > (), < a href = "ntqiodevice.html#open" > open< / a > (), and < a href = "ntqiodevice.html#close" > close< / a > ().
< h3 class = fn > TQ_LONG < a name = "writeBlock" > < / a > TQBuffer::writeBlock ( const char * p, TQ_ULONG len )< tt > [virtual]< / tt >
< / h3 >
Writes < em > len< / em > bytes from < em > p< / em > 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.
< p > Returns -1 if an error occurred.
< p > < p > See also < a href = "ntqiodevice.html#readBlock" > readBlock< / a > ().
< p > Reimplemented from < a href = "ntqiodevice.html#writeBlock" > TQIODevice< / a > .
< h3 class = fn > TQ_LONG < a name = "writeBlock-2" > < / a > TQBuffer::writeBlock ( const < a href = "qbytearray.html" > TQByteArray< / a > & data )
< / h3 >
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
< p > This convenience function is the same as calling
< tt > writeBlock( data.data(), data.size() )< / tt > with < em > data< / em > .
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