Moved files to be PSR-4 compliant

Author: castarco

src/AbelianAdditiveGroup.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace Litipk\BigNumbers;
+
+/**
+ * Immutable object that represents an element from an abelian additive group
+ * 
+ * @author Andreu Correa Casablanca <[email protected]>
+ */
+interface AbelianAdditiveGroup
+{
+    /**
+     * Returns the element's additive inverse.
+     * 
+     * @return AbelianAdditiveGroup
+     */
+    public function additiveInverse();
+}

src/BigNumber.php

@@ -0,0 +1,78 @@
+<?php
+
+namespace Litipk\BigNumbers;
+
+/**
+ * BigNumber Interface
+ * 
+ * @author Andreu Correa Casablanca <[email protected]>
+ */
+interface BigNumber
+{
+    /**
+     * Adds two big numbers
+     * 
+     * @param BigNumber $b
+     * @return BigNumber
+     */
+    public function add(BigNumber $b);
+
+    /**
+     * Substracts $b from $this
+     * 
+     * @param  BigNumber $b
+     * @return BigNumber
+     */
+    public function sub(BigNumber $b);
+
+    /**
+     * Multiplies two big numbers
+     * 
+     * @param  BigNumber $b
+     * @return BigNumber
+     */
+    public function mul(BigNumber $b);
+
+    /**
+     * Divides $this by $b
+     * 
+     * @param  BigNumber $b
+     * @return BigNumber
+     */
+    public function div(BigNumber $b);
+
+    /**
+     * @return boolean
+     */
+    public function isZero();
+
+    /**
+     * @return boolean
+     */
+    public function isPositive();
+
+    /**
+     * @return boolean
+     */
+    public function isNegative();
+
+    /**
+     * @return boolean
+     */
+    public function isInfinite();
+
+    /**
+     * Says if this object is a "Not a Number"
+     * 
+     * @return boolean
+     */
+    public function isNaN();
+
+    /**
+     * Equality comparison between this object and $b
+     * 
+     * @param  BigNumber $b
+     * @return boolean
+     */
+    public function equals(BigNumber $b);
+}