// 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_shift
//! @{

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

  typedef typename T1::elem_type eT;

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

  const uword len = in.aux_uword_a;
  const uword neg = in.aux_uword_b;

  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_shift::apply_noalias(tmp, U.M, len, neg, dim);

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

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

  arma_conform_check_bounds(((dim == 0) && (len >= X.n_rows)),
                            "shift(): shift amount out of bounds");
  arma_conform_check_bounds(((dim == 1) && (len >= X.n_cols)),
                            "shift(): shift amount out of bounds");

  if (len == 0) {
    out = X;
    return;
  }

  out.copy_size(X);

  const uword X_n_rows = X.n_rows;
  const uword X_n_cols = X.n_cols;

  if (dim == 0) {
    if (neg == 0) {
      for (uword col = 0; col < X_n_cols; ++col) {
        eT* out_ptr = out.colptr(col);
        const eT* X_ptr = X.colptr(col);

        for (uword out_row = len, row = 0; row < (X_n_rows - len); ++row, ++out_row) {
          out_ptr[out_row] = X_ptr[row];
        }

        for (uword out_row = 0, row = (X_n_rows - len); row < X_n_rows;
             ++row, ++out_row) {
          out_ptr[out_row] = X_ptr[row];
        }
      }
    } else if (neg == 1) {
      for (uword col = 0; col < X_n_cols; ++col) {
        eT* out_ptr = out.colptr(col);
        const eT* X_ptr = X.colptr(col);

        for (uword out_row = 0, row = len; row < X_n_rows; ++row, ++out_row) {
          out_ptr[out_row] = X_ptr[row];
        }

        for (uword out_row = (X_n_rows - len), row = 0; row < len; ++row, ++out_row) {
          out_ptr[out_row] = X_ptr[row];
        }
      }
    }
  } else if (dim == 1) {
    if (neg == 0) {
      if (X_n_rows == 1) {
        eT* out_ptr = out.memptr();
        const eT* X_ptr = X.memptr();

        for (uword out_col = len, col = 0; col < (X_n_cols - len); ++col, ++out_col) {
          out_ptr[out_col] = X_ptr[col];
        }

        for (uword out_col = 0, col = (X_n_cols - len); col < X_n_cols;
             ++col, ++out_col) {
          out_ptr[out_col] = X_ptr[col];
        }
      } else {
        for (uword out_col = len, col = 0; col < (X_n_cols - len); ++col, ++out_col) {
          arrayops::copy(out.colptr(out_col), X.colptr(col), X_n_rows);
        }

        for (uword out_col = 0, col = (X_n_cols - len); col < X_n_cols;
             ++col, ++out_col) {
          arrayops::copy(out.colptr(out_col), X.colptr(col), X_n_rows);
        }
      }
    } else if (neg == 1) {
      if (X_n_rows == 1) {
        eT* out_ptr = out.memptr();
        const eT* X_ptr = X.memptr();

        for (uword out_col = 0, col = len; col < X_n_cols; ++col, ++out_col) {
          out_ptr[out_col] = X_ptr[col];
        }

        for (uword out_col = (X_n_cols - len), col = 0; col < len; ++col, ++out_col) {
          out_ptr[out_col] = X_ptr[col];
        }
      } else {
        for (uword out_col = 0, col = len; col < X_n_cols; ++col, ++out_col) {
          arrayops::copy(out.colptr(out_col), X.colptr(col), X_n_rows);
        }

        for (uword out_col = (X_n_cols - len), col = 0; col < len; ++col, ++out_col) {
          arrayops::copy(out.colptr(out_col), X.colptr(col), X_n_rows);
        }
      }
    }
  }
}

//! @}
