tree a6325af5094d9d638420775960dc2a0c1f07e4b2
parent 2c1e595b775f6c23ec985ac20976f81dbed327e5
author Sameer Agarwal <sameeragarwal@google.com> 1531001688 -0700
committer Sameer Agarwal <sameeragarwal@google.com> 1531203454 +0000

Fix three out of bounds errors in CompressedRowSparseMatrix.

All three errors are of the form where, the vector storing
the columns array for a CompressedRowSparseMatrix is being
accessed out of bounds. But in each case, the access is innocuous
because there are other tests which prevent it from being used.

However, if one compiles with debug mode on, the bounds checking
in the underlying std::vector triggers an error.

More details:

1. FromTripletSparseMatrix tried accessing the col vector of
   a matrix with zero rows, but the following code was a no-op
   because there was nothing to copy.

   Adding an early return which deals with this case fixes this.

2. RightMultiply and SquaredColumnNorm had the following loop

   while (r > cols_[idx] && idx < idx_end) {
        ++idx;
   }

   where cols_ was being accessed out of bounds, before idx < idx_end
   was being checked. Swapping the order of the comparisons fixes this
   error.

@richmattes reported this error.

https://github.com/ceres-solver/ceres-solver/issues/383

Change-Id: I2dbc90ef24ecaffc6f46f1622339d6053b43db45