Move the out of boundary check in right place in bit reader

Author: klermonte

src/BinaryReader.php

@@ -114,7 +114,8 @@ public function isEof()
     }
 
     /**
-     * @ return bool
+     * @param int $length
+     * @return bool
      */
     public function canReadBytes($length = 0)
     {

src/Type/Bit.php

@@ -28,10 +28,6 @@ public function read(BinaryReader &$br, $length)
             throw new InvalidDataException('The length parameter must be an integer');
         }
 
-        if (!$br->canReadBytes($length / 8)) {
-            throw new \OutOfBoundsException('Cannot read bits, it exceeds the boundary of the file');
-        }
-
         $bitmask = new BitMask();
         $result = 0;
         $bits = $length;
@@ -54,6 +50,10 @@ public function read(BinaryReader &$br, $length)
             }
         }
 
+        if (!$br->canReadBytes($length / 8)) {
+            throw new \OutOfBoundsException('Cannot read bits, it exceeds the boundary of the file');
+        }
+
         if ($bits >= 8) {
             $bytes = intval($bits / 8);
 

test/Type/BitTest.php

@@ -35,6 +35,14 @@ public function testUnsignedBitReader($brBig, $brLittle)
         $this->assertEquals(0, $brLittle->readUBits(4));
         $this->assertEquals(0, $brBig->readUBits(2));
         $this->assertEquals(0, $brLittle->readUBits(2));
+
+        $brBig->readUBits(80);
+        $brLittle->readUBits(80);
+
+        $this->assertEquals(0xF, $brBig->readUBits(4));
+        $this->assertEquals(0xF, $brLittle->readUBits(4));
+        $this->assertEquals(3, $brBig->readUBits(2));
+        $this->assertEquals(3, $brLittle->readUBits(2));
     }
 
     /**
@@ -100,4 +108,30 @@ public function testExceptionInvalidBitCountLittleEndian($brBig, $brLittle)
     {
         $brLittle->readBits('foo');
     }
+
+    /**
+     * @expectedException \OutOfBoundsException
+     * @dataProvider binaryReaders
+     */
+    public function testExceptionBitsOnLastBitsBigEndian($brBig, $brLittle)
+    {
+        $brBig->setPosition(15);
+        $brBig->readBits(4);
+        $brBig->readBits(2);
+        $brBig->readBits(2);
+        $brBig->readBits(1);
+    }
+
+    /**
+     * @expectedException \OutOfBoundsException
+     * @dataProvider binaryReaders
+     */
+    public function testExceptionBitsOnLastBitsLittleEndian($brBig, $brLittle)
+    {
+        $brLittle->setPosition(15);
+        $brLittle->readBits(4);
+        $brLittle->readBits(2);
+        $brLittle->readBits(2);
+        $brLittle->readBits(1);
+    }
 }