Merge pull request #1372 from ivanimanishi/blockNegativeSteps

FrameRange : Prevent creation of FrameRanges with negative steps

Author: johnhaddon

Changes

@@ -1,6 +1,11 @@
 10.4.x.x (relative to 10.4.10.0)
 ========
 
+Fixes
+-----
+
+- FrameRange : Prevented creation of FrameRanges with negative steps
+
 10.4.10.0 (relative to 10.4.9.1)
 ========
 

src/IECore/FrameRange.cpp

@@ -58,6 +58,10 @@ FrameRange::FrameRange( Frame start, Frame end, Frame step ) : m_start( start ),
 	{
 		throw Exception( "FrameRange step cannot be zero" );
 	}
+	if ( step < 0 )
+	{
+		throw Exception( "FrameRange step cannot be negative. Consider using the reverse suffix instead." );
+	}
 }
 
 FrameRange::~FrameRange()
@@ -102,6 +106,10 @@ void FrameRange::setStep( Frame step )
 	{
 		throw Exception( "FrameRange step cannot be zero" );
 	}
+	if ( step < 0 )
+	{
+		throw Exception( "FrameRange step cannot be negative. Consider using the reverse suffix instead." );
+	}
 	m_step = step;
 }
 

test/IECore/FrameList.py

@@ -55,7 +55,24 @@ def testReverseConstruction( self ) :
 		self.assertEqual( f.asList(), [ 5, 4, 3, 2, 1 ] )
 		self.assertEqual( IECore.frameListFromList( [ 5, 4, 3, 2, 1 ] ), f )
 
+	def testFrameRange( self ) :
+
+		f = IECore.FrameList.parse( "1-5" )
+		self.assertTrue( isinstance( f, IECore.FrameRange ) )
+		self.assertEqual( f.asList(), [ 1, 2, 3, 4, 5 ] )
+		# test step
+		f = IECore.FrameList.parse( "10-20x5" )
+		self.assertTrue( isinstance( f, IECore.FrameRange ) )
+		self.assertEqual( f.asList(), [ 10, 15, 20 ] )
+		# start must be smaller or equal to end
+		self.assertRaises( Exception, IECore.FrameList.parse, "5-1"  )
+		# step must be positive
+		self.assertRaises( Exception, IECore.FrameList.parse, "1-5x0" )
+		self.assertRaises( Exception, IECore.FrameList.parse, "1-5x-1" )
+		self.assertRaises( Exception, IECore.FrameList.parse, "5-1x-1" )
+
+
 	## \todo: there should probably be a lot more tests in here...
 
 if __name__ == "__main__":
-        unittest.main()
+	unittest.main()