Change strlen to mb_strlen

composer.json

@@ -14,7 +14,8 @@
     }
   },
   "require": {
-    "php": ">=5.5.0"
+    "php": ">=5.5.0",
+    "ext-mbstring": "*"
   },
   "require-dev": {
     "phpunit/phpunit": "4.*"

src/Rules/Between.php

@@ -21,7 +21,7 @@ public function check($value)
         if (is_int($value)) {
             return $value >= $min AND $value <= $max;
         } elseif(is_string($value)) {
-            return strlen($value) >= $min AND strlen($value) <= $max;
+            return mb_strlen($value, 'UTF-8') >= $min AND mb_strlen($value, 'UTF-8') <= $max;
         } elseif(is_array($value)) {
             return count($value) >= $min AND count($value) <= $max;
         } else {

src/Rules/Required.php

@@ -20,7 +20,7 @@ public function check($value)
             return $this->isValueFromUploadedFiles($value) AND $value['error'] != UPLOAD_ERR_NO_FILE;
         }
 
-        if (is_string($value)) return strlen(trim($value)) > 0;
+        if (is_string($value)) return mb_strlen(trim($value), 'UTF-8') > 0;
         if (is_array($value)) return count($value) > 0;
         return !is_null($value);
     }

src/Validation.php

@@ -162,7 +162,7 @@ protected function initializeAttributeOnData($attributeKey)
 
         $asteriskPos = strpos($attributeKey, '*');
 
-        if (false === $asteriskPos || $asteriskPos === (strlen($attributeKey) - 1)) {
+        if (false === $asteriskPos || $asteriskPos === (mb_strlen($attributeKey, 'UTF-8') - 1)) {
             return $data;
         }
 

tests/Rules/BetweenTest.php

@@ -13,13 +13,15 @@ public function setUp()
     public function testValids()
     {
         $this->assertTrue($this->rule->fillParameters([6, 10])->check('foobar'));
+        $this->assertTrue($this->rule->fillParameters([6, 10])->check('футбол'));
         $this->assertTrue($this->rule->fillParameters([2, 3])->check([1,2,3]));
         $this->assertTrue($this->rule->fillParameters([100, 150])->check(123));
     }
 
     public function testInvalids()
     {
         $this->assertFalse($this->rule->fillParameters([2, 5])->check('foobar'));
+        $this->assertFalse($this->rule->fillParameters([2, 5])->check('футбол'));
         $this->assertFalse($this->rule->fillParameters([4, 6])->check([1,2,3]));
         $this->assertFalse($this->rule->fillParameters([50, 100])->check(123));
     }