1 files changed, 73 insertions, 0 deletions
diff --git a/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Engine/CyclicReferenceStack.php b/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Engine/CyclicReferenceStack.php
new file mode 100644
index 0000000..877ab1b
--- /dev/null
+++ b/vendor/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Engine/CyclicReferenceStack.php
@@ -0,0 +1,73 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Engine;
+
+class CyclicReferenceStack
+{
+    /**
+     * The call stack for calculated cells.
+     *
+     * @var mixed[]
+     */
+    private $stack = [];
+
+    /**
+     * Return the number of entries on the stack.
+     *
+     * @return int
+     */
+    public function count()
+    {
+        return count($this->stack);
+    }
+
+    /**
+     * Push a new entry onto the stack.
+     *
+     * @param mixed $value
+     */
+    public function push($value): void
+    {
+        $this->stack[$value] = $value;
+    }
+
+    /**
+     * Pop the last entry from the stack.
+     *
+     * @return mixed
+     */
+    public function pop()
+    {
+        return array_pop($this->stack);
+    }
+
+    /**
+     * Test to see if a specified entry exists on the stack.
+     *
+     * @param mixed $value The value to test
+     *
+     * @return bool
+     */
+    public function onStack($value)
+    {
+        return isset($this->stack[$value]);
+    }
+
+    /**
+     * Clear the stack.
+     */
+    public function clear(): void
+    {
+        $this->stack = [];
+    }
+
+    /**
+     * Return an array of all entries on the stack.
+     *
+     * @return mixed[]
+     */
+    public function showStack()
+    {
+        return $this->stack;
+    }
+}