// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

//! \addtogroup op_sp_diagvec
//! @{

template <typename T1>
inline void op_sp_diagvec::apply(
    Mat<typename T1::elem_type>& out,
    const mtSpReduceOp<typename T1::elem_type, T1, op_sp_diagvec>& in) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const unwrap_spmat<T1> U(in.m);
  const SpMat<eT>& X = U.M;

  const uword a = in.aux_uword_a;
  const uword b = in.aux_uword_b;

  const uword row_offset = (b > 0) ? a : 0;
  const uword col_offset = (b == 0) ? a : 0;

  arma_conform_check_bounds(((row_offset > 0) && (row_offset >= X.n_rows)) ||
                                ((col_offset > 0) && (col_offset >= X.n_cols)),
                            "diagvec(): requested diagonal out of bounds");

  const uword len = (std::min)(X.n_rows - row_offset, X.n_cols - col_offset);

  out.set_size(len, 1);

  eT* out_mem = out.memptr();

  for (uword i = 0; i < len; ++i) {
    out_mem[i] = X.at(i + row_offset, i + col_offset);
  }
}

//! @}
