// 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_reshape
//! @{

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

  typedef typename T1::elem_type eT;

  const uword new_n_rows = in.aux_uword_a;
  const uword new_n_cols = in.aux_uword_b;

  if (is_Mat<T1>::value || (arma_config::openmp && Proxy<T1>::use_mp)) {
    const unwrap<T1> U(in.m);
    const Mat<eT>& A = U.M;

    if (&actual_out == &A) {
      op_reshape::apply_mat_inplace(actual_out, new_n_rows, new_n_cols);
    } else {
      op_reshape::apply_mat_noalias(actual_out, A, new_n_rows, new_n_cols);
    }
  } else {
    const Proxy<T1> P(in.m);

    const bool is_alias = P.is_alias(actual_out);

    Mat<eT> tmp;
    Mat<eT>& out = (is_alias) ? tmp : actual_out;

    if (is_Mat<typename Proxy<T1>::stored_type>::value) {
      const quasi_unwrap<typename Proxy<T1>::stored_type> U(P.Q);

      op_reshape::apply_mat_noalias(out, U.M, new_n_rows, new_n_cols);
    } else {
      op_reshape::apply_proxy_noalias(out, P, new_n_rows, new_n_cols);
    }

    if (is_alias) {
      actual_out.steal_mem(tmp);
    }
  }
}

template <typename eT>
inline void op_reshape::apply_mat_inplace(Mat<eT>& A, const uword new_n_rows,
                                          const uword new_n_cols) {
  arma_debug_sigprint();

  arma_conform_check(
      (A.vec_state == 1) && (new_n_cols != 1),
      "reshape(): requested size is not compatible with column vector layout");
  arma_conform_check(
      (A.vec_state == 2) && (new_n_rows != 1),
      "reshape(): requested size is not compatible with row vector layout");

  const uword new_n_elem = new_n_rows * new_n_cols;

  if (A.n_elem == new_n_elem) {
    A.set_size(new_n_rows, new_n_cols);
    return;
  }

  Mat<eT> B;

  op_reshape::apply_mat_noalias(B, A, new_n_rows, new_n_cols);

  A.steal_mem(B);
}

template <typename eT>
inline void op_reshape::apply_mat_noalias(Mat<eT>& out, const Mat<eT>& A,
                                          const uword new_n_rows,
                                          const uword new_n_cols) {
  arma_debug_sigprint();

  out.set_size(new_n_rows, new_n_cols);

  const uword n_elem_to_copy = (std::min)(A.n_elem, out.n_elem);

  eT* out_mem = out.memptr();

  arrayops::copy(out_mem, A.memptr(), n_elem_to_copy);

  if (n_elem_to_copy < out.n_elem) {
    const uword n_elem_leftover = out.n_elem - n_elem_to_copy;

    arrayops::fill_zeros(&(out_mem[n_elem_to_copy]), n_elem_leftover);
  }
}

template <typename T1>
inline void op_reshape::apply_proxy_noalias(Mat<typename T1::elem_type>& out,
                                            const Proxy<T1>& P, const uword new_n_rows,
                                            const uword new_n_cols) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  out.set_size(new_n_rows, new_n_cols);

  const uword n_elem_to_copy = (std::min)(P.get_n_elem(), out.n_elem);

  eT* out_mem = out.memptr();

  if (Proxy<T1>::use_at == false) {
    typename Proxy<T1>::ea_type Pea = P.get_ea();

    for (uword i = 0; i < n_elem_to_copy; ++i) {
      out_mem[i] = Pea[i];
    }
  } else {
    uword i = 0;

    const uword P_n_rows = P.get_n_rows();
    const uword P_n_cols = P.get_n_cols();

    for (uword col = 0; col < P_n_cols; ++col)
      for (uword row = 0; row < P_n_rows; ++row) {
        if (i >= n_elem_to_copy) {
          goto nested_loop_end;
        }

        out_mem[i] = P.at(row, col);

        ++i;
      }

  nested_loop_end:;
  }

  if (n_elem_to_copy < out.n_elem) {
    const uword n_elem_leftover = out.n_elem - n_elem_to_copy;

    arrayops::fill_zeros(&(out_mem[n_elem_to_copy]), n_elem_leftover);
  }
}

template <typename T1>
inline void op_reshape::apply(Cube<typename T1::elem_type>& out,
                              const OpCube<T1, op_reshape>& in) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const unwrap_cube<T1> U(in.m);
  const Cube<eT>& A = U.M;

  const uword new_n_rows = in.aux_uword_a;
  const uword new_n_cols = in.aux_uword_b;
  const uword new_n_slices = in.aux_uword_c;

  if (&out == &A) {
    op_reshape::apply_cube_inplace(out, new_n_rows, new_n_cols, new_n_slices);
  } else {
    op_reshape::apply_cube_noalias(out, A, new_n_rows, new_n_cols, new_n_slices);
  }
}

template <typename eT>
inline void op_reshape::apply_cube_inplace(Cube<eT>& A, const uword new_n_rows,
                                           const uword new_n_cols,
                                           const uword new_n_slices) {
  arma_debug_sigprint();

  const uword new_n_elem = new_n_rows * new_n_cols * new_n_slices;

  if (A.n_elem == new_n_elem) {
    A.set_size(new_n_rows, new_n_cols, new_n_slices);
    return;
  }

  Cube<eT> B;

  op_reshape::apply_cube_noalias(B, A, new_n_rows, new_n_cols, new_n_slices);

  A.steal_mem(B);
}

template <typename eT>
inline void op_reshape::apply_cube_noalias(Cube<eT>& out, const Cube<eT>& A,
                                           const uword new_n_rows, const uword new_n_cols,
                                           const uword new_n_slices) {
  arma_debug_sigprint();

  out.set_size(new_n_rows, new_n_cols, new_n_slices);

  const uword n_elem_to_copy = (std::min)(A.n_elem, out.n_elem);

  eT* out_mem = out.memptr();

  arrayops::copy(out_mem, A.memptr(), n_elem_to_copy);

  if (n_elem_to_copy < out.n_elem) {
    const uword n_elem_leftover = out.n_elem - n_elem_to_copy;

    arrayops::fill_zeros(&(out_mem[n_elem_to_copy]), n_elem_leftover);
  }
}

//! @}
