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author | Ivan Enderlin <ivan.enderlin@hoa-project.net> | 2013-04-23 17:36:51 +0200 |
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committer | Ivan Enderlin <ivan.enderlin@hoa-project.net> | 2013-04-23 17:36:51 +0200 |
commit | 2af5ad6a1369e1c6c810dab998b1eab1215f2349 (patch) | |
tree | c32b1462998ea61f23c12d0454e171c4ce43e6f4 /Iterator | |
parent | 73afcad19993e283d0945a3d5be25b8250ef4898 (diff) | |
download | Praspel-2af5ad6a1369e1c6c810dab998b1eab1215f2349.zip Praspel-2af5ad6a1369e1c6c810dab998b1eab1215f2349.tar.gz Praspel-2af5ad6a1369e1c6c810dab998b1eab1215f2349.tar.bz2 |
Add a weak stack.
A weak stack is a stack where null elements are not iterated. Example:
$stack = new WeakStack();
$stack->push(2);
$stack->push(null);
$stack->push(4);
$stack->push(null);
$stack->push(null);
$stack->pop();
foreach($stack as $element)
var_dump($element);
/**
* Will output:
* int(4)
* int(2)
*/
Diffstat (limited to 'Iterator')
-rw-r--r-- | Iterator/WeakStack.php | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/Iterator/WeakStack.php b/Iterator/WeakStack.php new file mode 100644 index 0000000..df51ae5 --- /dev/null +++ b/Iterator/WeakStack.php @@ -0,0 +1,67 @@ +<?php + +/** + * Hoa + * + * + * @license + * + * New BSD License + * + * Copyright © 2007-2013, Ivan Enderlin. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of the Hoa nor the names of its contributors may be + * used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +namespace Hoa\Praspel\Iterator { + +/** + * Class \Hoa\Praspel\Iterator\WeakStack. + * + * A weak stack is a SplStack with null element that are not iterated. + * + * @author Ivan Enderlin <ivan.enderlin@hoa-project.net> + * @copyright Copyright © 2007-2013 Ivan Enderlin. + * @license New BSD License + */ + +class WeakStack extends \SplStack { + + /** + * Skip null elements while validated the current one. + * + * @access public + * @return bool + */ + public function valid ( ) { + + while( true === parent::valid() + && null === $this->current() + && null === parent::next()); + + return parent::valid(); + } +} + +} |