Move custom libs to the source tree

libs/SimpleValidator/Validators/Length.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace SimpleValidator\Validators;
+
+class Length extends Base
+{
+    private $min;
+    private $max;
+
+    public function __construct($field, $error_message, $min, $max)
+    {
+        parent::__construct($field, $error_message);
+        $this->min = $min;
+        $this->max = $max;
+    }
+
+    public function execute(array $data)
+    {
+        if ($this->isFieldNotEmpty($data)) {
+            $length = mb_strlen($data[$this->field], 'UTF-8');
+            return $length >= $this->min && $length <= $this->max;
+        }
+
+        return true;
+    }
+}