From 59250e8288c3298e1d4a4b4ec3b23e381d2b5f20 Mon Sep 17 00:00:00 2001
From: Artur Wieczorek <artwik@wp.pl>
Date: Sun, 27 Apr 2014 19:22:29 +0200
Subject: [PATCH] cv::findContours: Check if type of output data structure is
 right to store contours (vector<vector<Point>>).

---
 modules/imgproc/src/contours.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/modules/imgproc/src/contours.cpp b/modules/imgproc/src/contours.cpp
index 797f8c56c..4c77dd285 100644
--- a/modules/imgproc/src/contours.cpp
+++ b/modules/imgproc/src/contours.cpp
@@ -1703,6 +1703,10 @@ cvFindContours( void*  img,  CvMemStorage*  storage,
 void cv::findContours( InputOutputArray _image, OutputArrayOfArrays _contours,
                    OutputArray _hierarchy, int mode, int method, Point offset )
 {
+    // Sanity check: output must be of type vector<vector<Point>>
+    CV_Assert( _contours.kind() == _InputArray::STD_VECTOR_VECTOR &&
+               _contours.channels() == 2 && _contours.depth() == CV_32S );
+
     Mat image = _image.getMat();
     MemStorage storage(cvCreateMemStorage());
     CvMat _cimage = image;