BlockRandomAccessSparseMatrix::IntPairToLong suffers from integer
overflow.
Even though the return value of this function is a long int, the
computation happens with three ints, which causes an overflow before
the upgrade happens.
The fix is to upgrade the constant used int his computation to be a
long int, which causes the computation to be done in longs instead of
ints.
A test has been added to verify that the fix works.
Change-Id: Ibb0aef877125bb37ca28754cb07b8e1627fd1d5a
diff --git a/internal/ceres/block_random_access_sparse_matrix_test.cc b/internal/ceres/block_random_access_sparse_matrix_test.cc
index 01a8c66..e4e6769 100644
--- a/internal/ceres/block_random_access_sparse_matrix_test.cc
+++ b/internal/ceres/block_random_access_sparse_matrix_test.cc
@@ -28,6 +28,7 @@
//
// Author: sameeragarwal@google.com (Sameer Agarwal)
+#include <limits>
#include <vector>
#include <glog/logging.h>
#include "gtest/gtest.h"
@@ -117,5 +118,32 @@
EXPECT_NEAR(dense.norm(), sqrt(9 + 16 * 16 + 36 * 20 + 9 * 15), kTolerance);
}
+// IntPairToLong is private, thus this fixture is needed to access and
+// test it.
+class BlockRandomAccessSparseMatrixTest : public ::testing::Test {
+ public:
+ virtual void SetUp() {
+ vector<int> blocks;
+ blocks.push_back(1);
+ set< pair<int, int> > block_pairs;
+ block_pairs.insert(make_pair(0, 0));
+ m_.reset(new BlockRandomAccessSparseMatrix(blocks, block_pairs));
+ }
+
+ void CheckIntPair(int a, int b) {
+ int64 value = m_->IntPairToLong(a, b);
+ EXPECT_GT(value, 0) << "Overflow a = " << a << " b = " << b;
+ EXPECT_GT(value, a) << "Overflow a = " << a << " b = " << b;
+ EXPECT_GT(value, b) << "Overflow a = " << a << " b = " << b;
+ }
+
+ private:
+ scoped_ptr<BlockRandomAccessSparseMatrix> m_;
+};
+
+TEST_F(BlockRandomAccessSparseMatrixTest, IntPairToLongOverflow) {
+ CheckIntPair(numeric_limits<int>::max(), numeric_limits<int>::max());
+}
+
} // namespace internal
} // namespace ceres
