Stringy\Stringy now implements the ArrayAccess interface

README.md

@@ -144,7 +144,7 @@ foreach ($stringy as $pos => $char) {
 // array('F', 'ò', 'ô', ' ', 'B', 'à', 'ř')
 ```
 
-It also implements the `countable` interface, enabling the use of `count()` to
+It also implements the `Countable` interface, enabling the use of `count()` to
 retrieve the number of characters in the string, given the encoding:
 
 ``` php

src/Stringy/Stringy.php

@@ -2,7 +2,7 @@
 
 namespace Stringy;
 
-class Stringy implements \Countable, \IteratorAggregate
+class Stringy implements \Countable, \IteratorAggregate, \ArrayAccess
 {
     private $str;
 
@@ -87,6 +87,81 @@ class Stringy implements \Countable, \IteratorAggregate
         return new \ArrayIterator($this->chars());
     }
 
+    /**
+     * Returns whether or not a character exists at the given index. Implements
+     * part of the ArrayAccess interface.
+     *
+     * @param   mixed    $offset  The index to check
+     * @return  boolean  Whether or not the index exists
+     */
+    public function offsetExists($offset) {
+        return ($this->length() > (int) $offset);
+    }
+
+    /**
+     * Returns the character at the given index, otherwise null if none exists.
+     * Implements part of the ArrayAccess interface.
+     *
+     * @param   mixed  $offset  The index from which to retrieve the char
+     * @return  mixed  The character if it exists, else null
+     */
+    public function offsetGet($offset) {
+        $offset = (int) $offset;
+        if ($this->length() <= $offset) {
+            return null;
+        }
+
+        return $this->at($offset);
+    }
+
+    /**
+     * Sets the character at the given offset. The value to set is truncated
+     * to a single character. If the offset is null or exceeds the length
+     * of the string, it is appended to the end. Implements part of the
+     * ArrayAccess interface.
+     *
+     * @param  mixed  $offset  The index at which to replace the character
+     * @param  mixed  $value   Value to set
+     */
+    public function offsetSet($offset, $value) {
+        $length = $this->length();
+        if ($offset === null || $length <= (int) $offset) {
+            $this->str .= $value;
+
+            return;
+        }
+
+        $offset = (int) $offset;
+        $value = mb_substr($value, 0, 1, $this->encoding);
+        $start = mb_substr($this->str, 0, $offset, $this->encoding);
+        $end = mb_substr($this->str, $offset + 1, $length, $this->encoding);
+
+        $this->str = $start . $value . $end;
+    }
+
+    /**
+     * Deletes character at the given offset. Implements part of the
+     * ArrayAccess interface.
+     *
+     * @param  mixed  $offset  The index at which to delete the character
+     */
+    public function offsetUnset($offset) {
+        $length = $this->length();
+        if ($offset === null || $length <= (int) $offset) {
+            return;
+        }
+
+        $offset = (int) $offset;
+        if ($offset === $length - 1) {
+            $this->str = $this->substr(0, $length - 1)->str;
+        }
+
+        $start = mb_substr($this->str, 0, $offset, $this->encoding);
+        $end = mb_substr($this->str, $offset + 1, $length, $this->encoding);
+
+        $this->str = $start . $end;
+    }
+
     /**
      * Returns an array consisting of the characters in the string.
      *

tests/Stringy/StringyTest.php

@@ -95,6 +95,81 @@ class StringyTestCase extends CommonTest
         $this->assertEquals(array('F', 'ò', 'ô', ' ', 'B', 'à', 'ř'), $keyValResult);
     }
 
+    public function testOffsetExists()
+    {
+        $stringy = S::create('fòô', 'UTF-8');
+
+        $this->assertTrue($stringy->offsetExists(0));
+        $this->assertTrue($stringy->offsetExists(2));
+        $this->assertFalse($stringy->offsetExists(3));
+
+        $this->assertTrue(isset($stringy[2]));
+        $this->assertFalse(isset($stringy[3]));
+    }
+
+    public function testOffsetGet()
+    {
+        $stringy = S::create('fòô', 'UTF-8');
+
+        $this->assertEquals('f', $stringy->offsetGet(0));
+        $this->assertEquals('ô', $stringy->offsetGet(2));
+        $this->assertEquals(null, $stringy->offsetGet(3));
+
+        $this->assertEquals('ô', $stringy[2]);
+        $this->assertEquals(null, $stringy[3]);
+    }
+
+    /**
+     * @dataProvider offsetSetProvider()
+     */
+    public function testOffsetSet($expected, $offset, $value)
+    {
+        $stringy = S::create('fòô', 'UTF-8');
+        $stringy->offsetSet($offset, $value);
+        $this->assertEquals($expected, (string) $stringy);
+
+        $stringy = S::create('fòô', 'UTF-8');
+        $stringy[$offset] = $value;
+        $this->assertEquals($expected, (string) $stringy);
+    }
+
+    public function offsetSetProvider()
+    {
+        return array(
+            array('ôòô', 0, 'ô'),
+            array('fòo', 2, 'o'),
+            array('fòôô', 3, 'ô'),
+            array('fòôô', 8, 'ô'),
+            array('fòôô', null, 'ô'),
+            array('fô', 1, ''),
+            array('fbô', 1, 'bar')
+        );
+    }
+
+    /**
+     * @dataProvider offsetUnsetProvider()
+     */
+    public function testOffsetUnset($expected, $offset)
+    {
+        $stringy = S::create('fòô', 'UTF-8');
+        $stringy->offsetUnset($offset);
+        $this->assertEquals($expected, (string) $stringy);
+
+        $stringy = S::create('fòô', 'UTF-8');
+        unset($stringy[$offset]);
+        $this->assertEquals($expected, (string) $stringy);
+    }
+
+    public function offsetUnsetProvider()
+    {
+        return array(
+            array('òô', 0),
+            array('fô', 1),
+            array('fò', 2),
+            array('fòô', 3)
+        );
+    }
+
     /**
      * @dataProvider charsProvider()
      */