// file: csnr_cal_3.cc
//
// this function hamming windows the signal
//

// system include file
//
#include <stdio.h>

// local include file
//
#include "global_constants.h"
#include "calculate_snr_constants.h"
#include "calculate_snr.h"

// function: hamming_window_signal_cc
//
// arguments:
//    float* hamming_window_signal_a: (output) hamming signal
//    float* signal_window_a: (input) buffer contain the signal to
//                             be pre-emphasized
//    int samples_per_win_a: (input) number of samples per window
//    int num_chans_a: (input) number of channels
//    int debug_mode_a: (input) debug level
//
// return: an int to indicate status
//
// this function hamming windows the signal using 
//
//
int hamming_window_signal_cc (float*& hamming_window_signal_a,
			      float* signal_window_a, int samples_per_win_a,
			      int num_chans_a, int debug_mode_a) {

  int num_samples = samples_per_win_a * num_chans_a;
  
  for (int j = 0; j < num_chans_a; j++) {
    for (int i = j; i < num_samples; i += num_chans_a) {
      hamming_window_signal_a[i] = signal_window_a[i] * ( 0.54 - 0.46 *
        cos( 2 * 3.14 * (float)(i / num_chans_a) / (samples_per_win_a - 1) ) );
    }
  }

  if (debug_mode_a > DEBUG_FULL) {
    for (int j = 0; j < num_chans_a; j++) {
      for (int i = j; i < num_samples; i += num_chans_a) {
	fprintf(stdout, "chan %d :: hamming windowed signal [%d] =  %.2f\n", j,
		i, hamming_window_signal_a[i]);
      }
    }
    fprintf(stdout, "\n");
  }
  
  // exit gracefully
  //
  return TRUE;
}