BMat8: rows array by reference

Author: james-d-mitchell

include/bmat8.hpp

@@ -193,6 +193,7 @@ class BMat8 {
     size_t nr_rows() const;
     //! Returns a \c std::vector for rows of \c this
     std::vector<uint8_t> rows() const;
+    void rows(std::array<uint8_t, 8>&) const;
 
     //! Returns the cardinality of the row space of \c this
     //!

include/bmat8_impl.hpp

@@ -397,6 +397,13 @@ inline std::vector<uint8_t> BMat8::rows() const {
     return rows;
 }
 
+inline void BMat8::rows(std::array<uint8_t, 8>& rows) const {
+      rows.fill(0);
+      for (size_t i = 0; i < 8; ++i) {
+        rows[i] = static_cast<uint8_t>(_data << (8 * i) >> 56);
+      }
+    }
+
 inline size_t BMat8::nr_rows() const {
     epu8 x = _mm_set_epi64x(_data, 0);
     return _mm_popcnt_u64(_mm_movemask_epi8(x != epu8 {}));