/* -*- c++ -*- */
/*
 * Copyright 2012 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "stream_mux_impl.h"
#include <gr_io_signature.h>
#include <string.h>
#include <cstdio>

#define VERBOSE 0

namespace gr {
  namespace blocks {

    stream_mux::sptr stream_mux::make(size_t itemsize, const std::vector<int> &lengths)
    {
      return gnuradio::get_initial_sptr(new stream_mux_impl(itemsize, lengths));
    }

    stream_mux_impl::stream_mux_impl(size_t itemsize, const std::vector<int> &lengths)
      : gr_block("stream_mux",
		 gr_make_io_signature (1, -1, itemsize),
		 gr_make_io_signature (1, 1, itemsize)),
	d_itemsize(itemsize),
	d_stream(0),
	d_residual(0),
	d_lengths(lengths)
    {
      if(d_lengths[d_stream] == 0) {
	increment_stream();
      }
      d_residual = d_lengths[d_stream];
    }

    void
    stream_mux_impl::forecast(int noutput_items, gr_vector_int &ninput_items_required)
    {
      unsigned ninputs = ninput_items_required.size ();
      for (unsigned i = 0; i < ninputs; i++)
	ninput_items_required[i] = (d_lengths[i] == 0 ? 0 : 1);
    }

    void 
    stream_mux_impl::increment_stream()
    {
      do {
	d_stream = (d_stream+1) % d_lengths.size();
      } while(d_lengths[d_stream] == 0);
      
      d_residual = d_lengths[d_stream];
    }


    int
    stream_mux_impl::general_work(int noutput_items,
				   gr_vector_int &ninput_items,
				   gr_vector_const_void_star &input_items,
				   gr_vector_void_star &output_items)
    {
      char *out = (char *) output_items[0];
      const char *in;
      int out_index = 0;
      std::vector<int> input_index(d_lengths.size(), 0);
      
      if(VERBOSE) {
	printf("mux: nouput_items: %d   d_stream: %d\n", noutput_items, d_stream);
	for(size_t i = 0; i < d_lengths.size(); i++)
	  printf("\tninput_items[%zu]: %d\n", i, ninput_items[i]);
      }
      
      while (1) {
	int r = std::min(noutput_items - out_index,
			 std::min(d_residual,
				  ninput_items[d_stream] - input_index[d_stream]));
	if(VERBOSE) {
	  printf("mux: r=%d\n", r);
	  printf("\tnoutput_items - out_index: %d\n",
		 noutput_items - out_index);
	  printf("\td_residual: %d\n",
		 d_residual);
	  printf("\tninput_items[d_stream] - input_index[d_stream]: %d\n",
		 ninput_items[d_stream] - input_index[d_stream]);
	}
	
	if(r <= 0) {
	  return out_index;
	}
	
	in = (const char *) input_items[d_stream] + input_index[d_stream]*d_itemsize;
	
	memcpy(&out[out_index*d_itemsize], in, r*d_itemsize);
	out_index += r;
	input_index[d_stream] += r;
	d_residual -= r;
	
	consume(d_stream, r);
	
	if(d_residual == 0) {
	  increment_stream();
	}
      }
    }
  } /* namespace blocks */
} /* namespace gr */