/* -*- c++ -*- */
/*
 * Copyright 2005,2013 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio 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, or (at your option)
 * any later version.
 *
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef _GR_VCO_H_
#define _GR_VCO_H_

#include <vector>
#include <gr_sincos.h>
#include <cmath>
#include <gr_complex.h>

namespace gr {
  namespace blocks {

    /*!
     * \brief base class template for Voltage Controlled Oscillator (VCO)
     * \ingroup misc
     *
     * Simple calculations of sine and cosine. Set the phase using
     * set_phase or adjust it by some delta using adjust_phase. Sine
     * and cosine can be retrieved together with sincos(sinx, cosx)
     * where sinx and cosx are the returned values at the current
     * phase. They can be retrieved individually using either sin() or
     * cos().
     *
     * \sa fxpt_nco.h for fixed-point implementation.
     */

    template<class o_type, class i_type>
    class vco
    {
    public:
      vco() : d_phase(0) {}

      virtual ~vco() {}

      //! Set the current phase \p angle in radians 
      void set_phase(double angle) {
        d_phase = angle;
      }

      //! Update the current phase in radians by \p delta_phase
      void adjust_phase(double delta_phase) {
        d_phase += delta_phase;
        if(fabs(d_phase) > M_PI) {

          while(d_phase > M_PI)
            d_phase -= 2*M_PI;

          while(d_phase < -M_PI)
            d_phase += 2*M_PI;
        }
      }

      //! Get the current phase in radians
      double get_phase() const { return d_phase; }

      //! compute sin and cos for current phase angle
      void sincos(float *sinx, float *cosx) const;

      //! compute cos or sin for current phase angle
      float cos() const { return std::cos(d_phase); }
      float sin() const { return std::sin(d_phase); }

      //! compute a block at a time
      void cos(float *output, const float *input, int noutput_items,
               double k, double ampl = 1.0);

    protected:
      double d_phase;
    };

    template<class o_type, class i_type>
    void
    vco<o_type,i_type>::sincos(float *sinx, float *cosx) const
    {
      gr_sincosf(d_phase, sinx, cosx);
    }

    template<class o_type, class i_type>
    void
    vco<o_type,i_type>::cos(float *output, const float *input, int noutput_items,
                            double k, double ampl)
    {
      for(int i = 0; i < noutput_items; i++) {
        output[i] = cos() * ampl;
        adjust_phase(input[i] * k);
      }
    }

  } /* namespace blocks */
} /* namespace gr */

#endif /* _VCO_H_ */