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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>QBitArray Class Reference</h1>
<p>The QBitArray class provides an array of bits.
<a href="#details">More...</a>
<p>All the functions in this class are <a href="threads.html#reentrant">reentrant</a> when Qt is built with thread support.</p>
<p><tt>#include <<a href="qbitarray-h.html">qbitarray.h</a>></tt>
<p>Inherits <a href="qbytearray.html">QByteArray</a>.
<p><a href="qbitarray-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li class=fn><a href="#QBitArray"><b>QBitArray</b></a> ()</li>
<li class=fn><a href="#QBitArray-2"><b>QBitArray</b></a> ( uint size )</li>
<li class=fn><a href="#QBitArray-3"><b>QBitArray</b></a> ( const QBitArray & a )</li>
<li class=fn>QBitArray & <a href="#operator-eq"><b>operator=</b></a> ( const QBitArray & a )</li>
<li class=fn>uint <a href="#size"><b>size</b></a> () const</li>
<li class=fn>bool <a href="#resize"><b>resize</b></a> ( uint size )</li>
<li class=fn>bool <a href="#fill"><b>fill</b></a> ( bool v, int size = -1 )</li>
<li class=fn>virtual void <a href="#detach"><b>detach</b></a> ()</li>
<li class=fn>QBitArray <a href="#copy"><b>copy</b></a> () const</li>
<li class=fn>bool <a href="#testBit"><b>testBit</b></a> ( uint index ) const</li>
<li class=fn>void <a href="#setBit-2"><b>setBit</b></a> ( uint index )</li>
<li class=fn>void <a href="#setBit"><b>setBit</b></a> ( uint index, bool value )</li>
<li class=fn>void <a href="#clearBit"><b>clearBit</b></a> ( uint index )</li>
<li class=fn>bool <a href="#toggleBit"><b>toggleBit</b></a> ( uint index )</li>
<li class=fn>bool <a href="#at"><b>at</b></a> ( uint index ) const</li>
<li class=fn>QBitVal <a href="#operator[]"><b>operator[]</b></a> ( int index )</li>
<li class=fn>bool <a href="#operator[]-2"><b>operator[]</b></a> ( int index ) const</li>
<li class=fn>QBitArray & <a href="#operator-and-eq"><b>operator&=</b></a> ( const QBitArray & a )</li>
<li class=fn>QBitArray & <a href="#operator|-eq"><b>operator|=</b></a> ( const QBitArray & a )</li>
<li class=fn>QBitArray & <a href="#operator^-eq"><b>operator^=</b></a> ( const QBitArray & a )</li>
<li class=fn>QBitArray <a href="#operator~"><b>operator~</b></a> () const</li>
</ul>
<h2>Related Functions</h2>
<ul>
<li class=fn>QBitArray <a href="#operator-and"><b>operator&</b></a> ( const QBitArray & a1, const QBitArray & a2 )</li>
<li class=fn>QBitArray <a href="#operator|"><b>operator|</b></a> ( const QBitArray & a1, const QBitArray & a2 )</li>
<li class=fn>QBitArray <a href="#operator^"><b>operator^</b></a> ( const QBitArray & a1, const QBitArray & a2 )</li>
<li class=fn>QDataStream & <a href="#operator-lt-lt"><b>operator<<</b></a> ( QDataStream & s, const QBitArray & a )</li>
<li class=fn>QDataStream & <a href="#operator-gt-gt"><b>operator>></b></a> ( QDataStream & s, QBitArray & a )</li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The QBitArray class provides an array of bits.
<p>
<p> Because QBitArray is a <a href="qmemarray.html">QMemArray</a>, it uses explicit <a href="shclass.html">sharing</a> with a reference count.
<p> A QBitArray is a special byte array that can access individual
bits and perform bit-operations (AND, OR, XOR and NOT) on entire
arrays or bits.
<p> Bits can be manipulated by the <a href="#setBit">setBit</a>() and <a href="#clearBit">clearBit</a>() functions,
but it is also possible to use the indexing [] operator to test
and set individual bits. The [] operator is a little slower than
setBit() and clearBit() because some tricks are required to
implement single-bit assignments.
<p> Example:
<pre>
QBitArray a(3);
a.<a href="#setBit">setBit</a>( 0 );
a.<a href="#clearBit">clearBit</a>( 1 );
a.<a href="#setBit">setBit</a>( 2 ); // a = [1 0 1]
QBitArray b(3);
b[0] = 1;
b[1] = 1;
b[2] = 0; // b = [1 1 0]
QBitArray c;
c = ~a & b; // c = [0 1 0]
</pre>
<p> When a QBitArray is constructed the bits are uninitialized. Use
<a href="#fill">fill</a>() to set all the bits to 0 or 1. The array can be resized
with <a href="#resize">resize</a>() and copied with <a href="#copy">copy</a>(). Bits can be set with
setBit() and cleared with clearBit(). Bits can be toggled with
<a href="#toggleBit">toggleBit</a>(). A bit's value can be obtained with <a href="#testBit">testBit</a>() and with
<a href="#at">at</a>().
<p> QBitArray supports the & (AND), | (OR), ^ (XOR) and ~ (NOT)
operators.
<p>See also <a href="collection.html">Collection Classes</a>, <a href="shared.html">Implicitly and Explicitly Shared Classes</a>, and <a href="tools.html">Non-GUI Classes</a>.
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="QBitArray"></a>QBitArray::QBitArray ()
</h3>
Constructs an empty bit array.
<h3 class=fn><a name="QBitArray-2"></a>QBitArray::QBitArray ( uint size )
</h3>
Constructs a bit array of <em>size</em> bits. The bits are uninitialized.
<p> <p>See also <a href="#fill">fill</a>().
<h3 class=fn><a name="QBitArray-3"></a>QBitArray::QBitArray ( const <a href="qbitarray.html">QBitArray</a> & a )
</h3>
<p> Constructs a <a href="shclass.html#shallow-copy">shallow copy</a> of <em>a</em>.
<h3 class=fn>bool <a name="at"></a>QBitArray::at ( uint index ) const
</h3>
<p> Returns the value (0 or 1) of the bit at position <em>index</em>.
<p> <p>See also <a href="#operator[]">operator[]</a>().
<h3 class=fn>void <a name="clearBit"></a>QBitArray::clearBit ( uint index )
</h3>
Clears the bit at position <em>index</em>, i.e. sets it to 0.
<p> <p>See also <a href="#setBit">setBit</a>() and <a href="#toggleBit">toggleBit</a>().
<h3 class=fn><a href="qbitarray.html">QBitArray</a> <a name="copy"></a>QBitArray::copy () const
</h3>
Returns a <a href="shclass.html#deep-copy">deep copy</a> of the bit array.
<p> <p>See also <a href="#detach">detach</a>().
<h3 class=fn>void <a name="detach"></a>QBitArray::detach ()<tt> [virtual]</tt>
</h3>
Detaches from shared bit array data and makes sure that this bit
array is the only one referring to the data.
<p> If multiple bit arrays share common data, this bit array
dereferences the data and gets a copy of the data. Nothing happens
if there is only a single reference.
<p> <p>See also <a href="#copy">copy</a>().
<p>Reimplemented from <a href="qmemarray.html#detach">QMemArray</a>.
<h3 class=fn>bool <a name="fill"></a>QBitArray::fill ( bool v, int size = -1 )
</h3>
Fills the bit array with <em>v</em> (1's if <em>v</em> is TRUE, or 0's if <em>v</em>
is FALSE).
<p> <a href="#fill">fill</a>() resizes the bit array to <em>size</em> bits if <em>size</em> is
nonnegative.
<p> Returns FALSE if a nonnegative <em>size</em> was specified and the bit
array could not be resized; otherwise returns TRUE.
<p> <p>See also <a href="#resize">resize</a>().
<h3 class=fn><a href="qbitarray.html">QBitArray</a> & <a name="operator-and-eq"></a>QBitArray::operator&= ( const <a href="qbitarray.html">QBitArray</a> & a )
</h3>
Performs the AND operation between all bits in this bit array and
<em>a</em>. Returns a reference to this bit array.
<p> The result has the length of the longest of the two bit arrays,
with any missing bits (i.e. if one array is shorter than the
other), taken to be 0.
<pre>
QBitArray a( 3 ), b( 2 );
a[0] = 1; a[1] = 0; a[2] = 1; // a = [1 0 1]
b[0] = 1; b[1] = 0; // b = [1 0]
a &= b; // a = [1 0 0]
</pre>
<p> <p>See also <a href="#operator|-eq">operator|=</a>(), <a href="#operator^-eq">operator^=</a>(), and <a href="#operator~">operator~</a>().
<h3 class=fn><a href="qbitarray.html">QBitArray</a> & <a name="operator-eq"></a>QBitArray::operator= ( const <a href="qbitarray.html">QBitArray</a> & a )
</h3>
<p> Assigns a <a href="shclass.html#shallow-copy">shallow copy</a> of <em>a</em> to this bit array and returns a
reference to this array.
<h3 class=fn><a href="qbitval.html">QBitVal</a> <a name="operator[]"></a>QBitArray::operator[] ( int index )
</h3>
<p> Implements the [] operator for bit arrays.
<p> The returned <a href="qbitval.html">QBitVal</a> is a context object. It makes it possible to
get and set a single bit value by its <em>index</em> position.
<p> Example:
<pre>
QBitArray a( 3 );
a[0] = 0;
a[1] = 1;
a[2] = a[0] ^ a[1];
</pre>
<p> The functions <a href="#testBit">testBit</a>(), <a href="#setBit">setBit</a>() and <a href="#clearBit">clearBit</a>() are faster.
<p> <p>See also <a href="#at">at</a>().
<h3 class=fn>bool <a name="operator[]-2"></a>QBitArray::operator[] ( int index ) const
</h3>
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
<p> Implements the [] operator for constant bit arrays.
<h3 class=fn><a href="qbitarray.html">QBitArray</a> & <a name="operator^-eq"></a>QBitArray::operator^= ( const <a href="qbitarray.html">QBitArray</a> & a )
</h3>
Performs the XOR operation between all bits in this bit array and
<em>a</em>. Returns a reference to this bit array.
<p> The result has the length of the longest of the two bit arrays,
with any missing bits (i.e. if one array is shorter than the
other), taken to be 0.
<pre>
QBitArray a( 3 ), b( 2 );
a[0] = 1; a[1] = 0; a[2] = 1; // a = [1 0 1]
b[0] = 1; b[1] = 0; // b = [1 0]
a ^= b; // a = [0 0 1]
</pre>
<p> <p>See also <a href="#operator-and-eq">operator&=</a>(), <a href="#operator|-eq">operator|=</a>(), and <a href="#operator~">operator~</a>().
<h3 class=fn><a href="qbitarray.html">QBitArray</a> & <a name="operator|-eq"></a>QBitArray::operator|= ( const <a href="qbitarray.html">QBitArray</a> & a )
</h3>
Performs the OR operation between all bits in this bit array and
<em>a</em>. Returns a reference to this bit array.
<p> The result has the length of the longest of the two bit arrays,
with any missing bits (i.e. if one array is shorter than the
other), taken to be 0.
<pre>
QBitArray a( 3 ), b( 2 );
a[0] = 1; a[1] = 0; a[2] = 1; // a = [1 0 1]
b[0] = 1; b[1] = 0; // b = [1 0]
a |= b; // a = [1 0 1]
</pre>
<p> <p>See also <a href="#operator-and-eq">operator&=</a>(), <a href="#operator^-eq">operator^=</a>(), and <a href="#operator~">operator~</a>().
<h3 class=fn><a href="qbitarray.html">QBitArray</a> <a name="operator~"></a>QBitArray::operator~ () const
</h3>
Returns a bit array that contains the inverted bits of this bit array.
<p> Example:
<pre>
QBitArray a( 3 ), b;
a[0] = 1; a[1] = 0; a[2] = 1; // a = [1 0 1]
b = ~a; // b = [0 1 0]
</pre>
<h3 class=fn>bool <a name="resize"></a>QBitArray::resize ( uint size )
</h3>
Resizes the bit array to <em>size</em> bits and returns TRUE if the bit
array could be resized; otherwise returns FALSE. The array becomes
a null array if <em>size</em> == 0.
<p> If the array is expanded, the new bits are set to 0.
<p> <p>See also <a href="#size">size</a>().
<h3 class=fn>void <a name="setBit"></a>QBitArray::setBit ( uint index, bool value )
</h3>
<p> Sets the bit at position <em>index</em> to <em>value</em>.
<p> Equivalent to:
<pre>
if ( value )
<a href="#setBit">setBit</a>( index );
else
<a href="#clearBit">clearBit</a>( index );
</pre>
<p> <p>See also <a href="#clearBit">clearBit</a>() and <a href="#toggleBit">toggleBit</a>().
<h3 class=fn>void <a name="setBit-2"></a>QBitArray::setBit ( uint index )
</h3>
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
<p> Sets the bit at position <em>index</em> to 1.
<p> <p>See also <a href="#clearBit">clearBit</a>() and <a href="#toggleBit">toggleBit</a>().
<h3 class=fn>uint <a name="size"></a>QBitArray::size () const
</h3>
<p> Returns the bit array's size (number of bits).
<p> <p>See also <a href="#resize">resize</a>().
<h3 class=fn>bool <a name="testBit"></a>QBitArray::testBit ( uint index ) const
</h3>
Returns TRUE if the bit at position <em>index</em> is set, i.e. is 1;
otherwise returns FALSE.
<p> <p>See also <a href="#setBit">setBit</a>() and <a href="#clearBit">clearBit</a>().
<h3 class=fn>bool <a name="toggleBit"></a>QBitArray::toggleBit ( uint index )
</h3>
Toggles the bit at position <em>index</em>.
<p> If the previous value was 0, the new value will be 1. If the
previous value was 1, the new value will be 0.
<p> <p>See also <a href="#setBit">setBit</a>() and <a href="#clearBit">clearBit</a>().
<hr><h2>Related Functions</h2>
<h3 class=fn><a href="qbitarray.html">QBitArray</a> <a name="operator-and"></a>operator& ( const <a href="qbitarray.html">QBitArray</a> & a1, const <a href="qbitarray.html">QBitArray</a> & a2 )
</h3>
<p> Returns the AND result between the bit arrays <em>a1</em> and <em>a2</em>.
<p> The result has the length of the longest of the two bit arrays,
with any missing bits (i.e. if one array is shorter than the
other), taken to be 0.
<p> <p>See also <a href="#operator-and-eq">QBitArray::operator&=</a>().
<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt"></a>operator<< ( <a href="qdatastream.html">QDataStream</a> & s, const <a href="qbitarray.html">QBitArray</a> & a )
</h3>
<p> Writes bit array <em>a</em> to stream <em>s</em>.
<p> <p>See also <a href="datastreamformat.html">Format of the QDataStream operators</a>.
<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt"></a>operator>> ( <a href="qdatastream.html">QDataStream</a> & s, <a href="qbitarray.html">QBitArray</a> & a )
</h3>
<p> Reads a bit array into <em>a</em> from stream <em>s</em>.
<p> <p>See also <a href="datastreamformat.html">Format of the QDataStream operators</a>.
<h3 class=fn><a href="qbitarray.html">QBitArray</a> <a name="operator^"></a>operator^ ( const <a href="qbitarray.html">QBitArray</a> & a1, const <a href="qbitarray.html">QBitArray</a> & a2 )
</h3>
<p> Returns the XOR result between the bit arrays <em>a1</em> and <em>a2</em>.
<p> The result has the length of the longest of the two bit arrays,
with any missing bits (i.e. if one array is shorter than the
other), taken to be 0.
<p> <p>See also <a href="#operator^">QBitArray::operator^</a>().
<h3 class=fn><a href="qbitarray.html">QBitArray</a> <a name="operator|"></a>operator| ( const <a href="qbitarray.html">QBitArray</a> & a1, const <a href="qbitarray.html">QBitArray</a> & a2 )
</h3>
<p> Returns the OR result between the bit arrays <em>a1</em> and <em>a2</em>.
<p> The result has the length of the longest of the two bit arrays,
with any missing bits (i.e. if one array is shorter than the
other), taken to be 0.
<p> <p>See also <a href="#operator|-eq">QBitArray::operator|=</a>().
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