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authorIvan Enderlin <ivan.enderlin@hoa-project.net>2013-04-23 17:36:51 +0200
committerIvan Enderlin <ivan.enderlin@hoa-project.net>2013-04-23 17:36:51 +0200
commit2af5ad6a1369e1c6c810dab998b1eab1215f2349 (patch)
treec32b1462998ea61f23c12d0454e171c4ce43e6f4 /Iterator
parent73afcad19993e283d0945a3d5be25b8250ef4898 (diff)
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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.php67
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();
+ }
+}
+
+}