/*!
 * \file
 * \brief Resampling functions - header file
 * \author Tony Ottosson and Adam Piatyszek
 *
 * -------------------------------------------------------------------------
 *
 * Copyright (C) 1995-2010  (see AUTHORS file for a list of contributors)
 *
 * This file is part of IT++ - a C++ library of mathematical, signal
 * processing, speech processing, and communications classes and functions.
 *
 * IT++ is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any
 * later version.
 *
 * IT++ is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along
 * with IT++.  If not, see <http://www.gnu.org/licenses/>.
 *
 * -------------------------------------------------------------------------
 */

#ifndef RESAMPLING_H
#define RESAMPLING_H

#include <itpp/base/mat.h>


namespace itpp
{

/*!
 * \addtogroup resampling
 * @{
 */

//! Repeat each element in the vector \a norepeats times in sequence
template<class T>
Vec<T> repeat(const Vec<T> &v, int norepeats)
{
  Vec<T> temp(v.length()*norepeats);

  for (int i = 0; i < v.length(); i++) {
    for (int j = 0;j < norepeats;j++)
      temp(i*norepeats + j) = v(i);
  }
  return temp;
}

//! Repeats each column \a norepeats times in sequence
template<class T>
Mat<T> repeat(const Mat<T> &m, int norepeats)
{
  Mat<T> temp(m.rows(), m.cols()*norepeats);

  for (int j = 0; j < m.cols(); j++) {
    for (int i = 0;i < norepeats;i++) {
      temp.set_col(j*norepeats + i, m.get_col(j));
    }
  }
  return temp;
}

//! Upsample a vector by inserting \a (usf-1) zeros after each sample
template<class T>
void upsample(const Vec<T> &v, int usf, Vec<T> &u)
{
  it_assert_debug(usf >= 1, "upsample: upsampling factor must be equal or greater than one");
  u.set_size(v.length()*usf);
  u.clear();
  for (int i = 0;i < v.length();i++)
    u(i*usf) = v(i);
}


//! Upsample a vector by inserting \a (usf-1) zeros after each sample
template<class T>
Vec<T> upsample(const Vec<T> &v, int usf)
{
  Vec<T> u;
  upsample(v, usf, u);
  return u;
}

//! Upsample each column by inserting \a (usf-1) zeros after each column
template<class T>
void upsample(const Mat<T> &v, int usf, Mat<T> &u)
{
  it_assert_debug(usf >= 1, "upsample: upsampling factor must be equal or greater than one");
  u.set_size(v.rows(), v.cols()*usf);
  u.clear();
  for (int j = 0;j < v.cols();j++)
    u.set_col(j*usf, v.get_col(j));
}

//! Upsample each column by inserting \a (usf-1) zeros after each column
template<class T>
Mat<T> upsample(const Mat<T> &v, int usf)
{
  Mat<T> u;
  upsample(v, usf, u);
  return u;
}

//! Upsample each column by a factor of \a (usf-1) by linear interpolation
template<class T>
void lininterp(const Mat<T> &m, int usf, Mat<T> &u)
{
  it_assert_debug(usf >= 1, "lininterp: upsampling factor must be equal or greater than one");
  int L = (m.cols() - 1) * usf + 1;
  u.set_size(m.rows(), L);
  for (int i = 0; i < m.rows(); i++) {
    for (int j = 0; j < L - 1; j++)
      u(i, j) = (m(i, j / usf) + (j % usf) / ((double)usf) * (m(i, (j + usf) / usf) - m(i, j / usf)));
    u(i, L - 1) = m(i, m.cols() - 1);
  }
}

/*!
 * \brief Upsample each column of matrix \a m to achieve \a f_ups
 * frequency using linear interpolation
 * \author Adam Piatyszek
 *
 * This function performs upsampling of matrix \a m to achieve
 * \a nrof_samples samples at \a f_ups frequency starting from the sample
 * at \a t_start time. The frequency of input samples stored in the matrix
 * \a m is defined by the \a f_base parameter.
 */
template<class T>
Mat<T> lininterp(const Mat<T> &m, double f_base, double f_ups,
                 int nrof_samples, double t_start = 0)
{
  double t_base = 1 / f_base;
  double t_ups = 1 / f_ups;
  int rows = m.rows();
  int cols = m.cols();
  it_assert_debug(f_ups > f_base, "lininterp(): upsampled frequency must be greater than base frequency");
  it_assert_debug((t_start >= 0) && (t_start < cols * t_base), "lininterp(): incorrect start time offset");
  it_assert_debug((nrof_samples * t_ups + t_start) <= (cols * t_base), "lininterp(): too many samples required or input data to short");
  Mat<T> u(rows, nrof_samples);
  double curr_time = t_start;

  int i = 0;
  int k = 0;
  while (i < cols - 1) {
    while ((curr_time < (i + 1) * t_base) && (k < nrof_samples)) {
      for (int j = 0; j < rows; j++) {
        u(j, k) = (m(j, i) * ((i + 1) * t_base - curr_time)
                   - m(j, i + 1) * (i * t_base - curr_time)) / t_base;
      }
      k++;
      curr_time += t_ups;
    }
    i++;
  }
  return u;
}

//! Upsample each column by a factor of  \a (usf-1) by linear interpolation
template<class T>
Mat<T> lininterp(const Mat<T> &m, int usf)
{
  Mat<T> u;
  lininterp(m, usf, u);
  return u;
}

//! Upsample by a factor of  \a (usf-1) by linear interpolation
template<class T>
void lininterp(const Vec<T> &v, int usf, Vec<T> &u)
{
  it_assert_debug(usf >= 1, "lininterp(): upsampling factor must be equal or greater than one");
  int L = (v.length() - 1) * usf + 1;
  u.set_size(L);
  for (int j = 0; j < L - 1; j++) {
    u(j) = (v(j / usf) + (j % usf) / ((double)usf) * (v((j + usf) / usf) - v(j / usf)));
  }
  u(L - 1) = v(v.length() - 1);
}

//! Upsample by a factor of  \a (usf-1) by linear interpolation
template<class T>
Vec<T> lininterp(const Vec<T> &v, int usf)
{
  Vec<T> u;
  lininterp(v, usf, u);
  return u;
}

/*!
 * \brief Upsample vector \a v to achieve \a f_ups frequency using linear
 * interpolation
 * \author Adam Piatyszek
 *
 * This function performs upsampling of vector \a v to achieve
 * \a nrof_samples samples at \a f_ups frequency starting from the sample
 * at \a t_start time. The frequency of input samples stored in the vector
 * \a v is defined by the \a f_base parameter.
 */
template<class T>
Vec<T> lininterp(const Vec<T> &v, double f_base, double f_ups,
                 int nrof_samples, double t_start = 0)
{
  double t_base = 1 / f_base;
  double t_ups = 1 / f_ups;
  int len = v.length();
  it_assert_debug(f_ups > f_base, "lininterp(): upsampled frequency must be greater than base frequency");
  it_assert_debug((t_start >= 0) && (t_start < len * t_base), "lininterp(): incorrect start time offset");
  it_assert_debug((nrof_samples * t_ups + t_start) <= (len * t_base), "lininterp(): too many samples required or input data to short");
  Vec<T> u(nrof_samples);
  double curr_time = t_start;

  int i = 0;
  int k = 0;
  while (i < len - 1) {
    while ((curr_time < (i + 1) * t_base) && (k < nrof_samples)) {
      u(k) = (v(i) * ((i + 1) * t_base - curr_time)
              - v(i + 1) * (i * t_base - curr_time)) / t_base;
      k++;
      curr_time += t_ups;
    }
    i++;
  }
  return u;
}

/*!
 * @}
 */

#ifndef _MSC_VER

// ----------------------------------------------------------------------
// Instantiations
// ----------------------------------------------------------------------

//! Extern Template instantiation of repeat
extern template vec repeat(const vec &v, int norepeats);
//! Extern Template instantiation of repeat
extern template cvec repeat(const cvec &v, int norepeats);
//! Extern Template instantiation of repeat
extern template svec repeat(const svec &v, int norepeats);
//! Extern Template instantiation of repeat
extern template ivec repeat(const ivec &v, int norepeats);
//! Extern Template instantiation of repeat
extern template bvec repeat(const bvec &v, int norepeats);

//! Extern Template instantiation of repeat
extern template mat repeat(const mat &m, int norepeats);
//! Extern Template instantiation of repeat
extern template cmat repeat(const cmat &m, int norepeats);
//! Extern Template instantiation of repeat
extern template smat repeat(const smat &m, int norepeats);
//! Extern Template instantiation of repeat
extern template imat repeat(const imat &m, int norepeats);
//! Extern Template instantiation of repeat
extern template bmat repeat(const bmat &m, int norepeats);

//! Extern Template instantiation of upsample
extern template vec upsample(const vec &v, int usf);
//! Extern Template instantiation of upsample
extern template cvec upsample(const cvec &v, int usf);
//! Extern Template instantiation of upsample
extern template svec upsample(const svec &v, int usf);
//! Extern Template instantiation of upsample
extern template ivec upsample(const ivec &v, int usf);
//! Extern Template instantiation of upsample
extern template bvec upsample(const bvec &v, int usf);

//! Extern Template instantiation of upsample
extern template mat upsample(const mat &v, int usf);
//! Extern Template instantiation of upsample
extern template cmat upsample(const cmat &v, int usf);
//! Extern Template instantiation of upsample
extern template smat upsample(const smat &v, int usf);
//! Extern Template instantiation of upsample
extern template imat upsample(const imat &v, int usf);
//! Extern Template instantiation of upsample
extern template bmat upsample(const bmat &v, int usf);

//! Extern Template instantiation of upsample
extern template void upsample(const vec &v, int usf,  vec &u);
//! Extern Template instantiation of upsample
extern template void upsample(const cvec &v, int usf,  cvec &u);
//! Extern Template instantiation of upsample
extern template void upsample(const svec &v, int usf,  svec &u);
//! Extern Template instantiation of upsample
extern template void upsample(const ivec &v, int usf,  ivec &u);
//! Extern Template instantiation of upsample
extern template void upsample(const bvec &v, int usf,  bvec &u);

//! Extern Template instantiation of upsample
extern template void upsample(const mat &v, int usf,  mat &u);
//! Extern Template instantiation of upsample
extern template void upsample(const cmat &v, int usf,  cmat &u);
//! Extern Template instantiation of upsample
extern template void upsample(const smat &v, int usf,  smat &u);
//! Extern Template instantiation of upsample
extern template void upsample(const imat &v, int usf,  imat &u);
//! Extern Template instantiation of upsample
extern template void upsample(const bmat &v, int usf,  bmat &u);

//! Extern Template instantiation of liniterp
extern template vec lininterp(const vec &v, int usf);
//! Extern Template instantiation of liniterp
extern template cvec lininterp(const cvec &v, int usf);

//! Extern Template instantiation of liniterp
extern template mat lininterp(const mat &v, int usf);
//! Extern Template instantiation of liniterp
extern template cmat lininterp(const cmat &v, int usf);

//! Extern Template instantiation of liniterp
extern template void lininterp(const vec &v, int usf,  vec &u);
//! Extern Template instantiation of liniterp
extern template void lininterp(const cvec &v, int usf,  cvec &u);

//! Extern Template instantiation of liniterp
extern template void lininterp(const mat &v, int usf,  mat &u);
//! Extern Template instantiation of liniterp
extern template void lininterp(const cmat &v, int usf,  cmat &u);

//! Extern Template instantiation of liniterp
extern template mat lininterp(const mat &m, double f_base, double f_ups, int nrof_samples, double t_start);
//! Extern Template instantiation of liniterp
extern template cmat lininterp(const cmat &m, double f_base, double f_ups, int nrof_samples, double t_start);

//! Extern Template instantiation of liniterp
extern template vec lininterp(const vec &v, double f_base, double f_ups, int nrof_samples, double t_start);
//! Extern Template instantiation of liniterp
extern template cvec lininterp(const cvec &v, double f_base, double f_ups, int nrof_samples, double t_start);

#endif

} // namespace itpp

#endif // #ifndef RESAMPLING_H

