// 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_cumsum
//! @{

template <typename eT>
inline void op_cumsum::apply_noalias(Mat<eT>& out, const Mat<eT>& X, const uword dim) {
  arma_debug_sigprint();

  uword n_rows = X.n_rows;
  uword n_cols = X.n_cols;

  out.set_size(n_rows, n_cols);

  if (out.n_elem == 0) {
    return;
  }

  if (dim == 0) {
    if (n_cols == 1) {
      const eT* X_mem = X.memptr();
      eT* out_mem = out.memptr();

      eT acc = eT(0);

      for (uword row = 0; row < n_rows; ++row) {
        acc += X_mem[row];

        out_mem[row] = acc;
      }
    } else {
      for (uword col = 0; col < n_cols; ++col) {
        const eT* X_colmem = X.colptr(col);
        eT* out_colmem = out.colptr(col);

        eT acc = eT(0);

        for (uword row = 0; row < n_rows; ++row) {
          acc += X_colmem[row];

          out_colmem[row] = acc;
        }
      }
    }
  } else if (dim == 1) {
    if (n_rows == 1) {
      const eT* X_mem = X.memptr();
      eT* out_mem = out.memptr();

      eT acc = eT(0);

      for (uword col = 0; col < n_cols; ++col) {
        acc += X_mem[col];

        out_mem[col] = acc;
      }
    } else {
      if (n_cols > 0) {
        arrayops::copy(out.colptr(0), X.colptr(0), n_rows);

        for (uword col = 1; col < n_cols; ++col) {
          const eT* out_colmem_prev = out.colptr(col - 1);
          eT* out_colmem = out.colptr(col);
          const eT* X_colmem = X.colptr(col);

          for (uword row = 0; row < n_rows; ++row) {
            out_colmem[row] = out_colmem_prev[row] + X_colmem[row];
          }
        }
      }
    }
  }
}

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

  typedef typename T1::elem_type eT;

  const uword dim = in.aux_uword_a;

  arma_conform_check((dim > 1), "cumsum(): parameter 'dim' must be 0 or 1");

  const quasi_unwrap<T1> U(in.m);

  if (U.is_alias(out)) {
    Mat<eT> tmp;

    op_cumsum::apply_noalias(tmp, U.M, dim);

    out.steal_mem(tmp);
  } else {
    op_cumsum::apply_noalias(out, U.M, dim);
  }
}

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

  typedef typename T1::elem_type eT;

  const quasi_unwrap<T1> U(in.m);

  const uword dim =
      (T1::is_xvec) ? uword(U.M.is_rowvec() ? 1 : 0) : uword((T1::is_row) ? 1 : 0);

  if (U.is_alias(out)) {
    Mat<eT> tmp;

    op_cumsum::apply_noalias(tmp, U.M, dim);

    out.steal_mem(tmp);
  } else {
    op_cumsum::apply_noalias(out, U.M, dim);
  }
}

//! @}
