// file: $SPEECH_HOMEWORK4/hw4/class/snr_ratio/v1.0/snr_read_0.cc
//

// isip include files
//
#include "signal_noise_ratio.h"
#include "signal_noise_ratio_constants.h"
#include <param_file.h>

// method: read_cc
//
// arguments:
//  FILE* fp (input) pointer to the input file
//  float_4*& buffer (output) the buffer to fill
//  int_4 start (input) the starting point to read
//  int_4 end (input) the end point to read
//  int_4 num_samples (input) the number of samples to read
//
// return: a logical_1 indicating status
//
logical_1 Signal::read_cc (FILE* fp_a, float_4*& buffer_a, int_4 start_a,
			   int_4 end_a, int_4 last_sample_a,
			   int_4& samples_read_a) {

  // check arguments
  //
  if (fp_a == (FILE*)NULL) {
    error_handler_cc((char_1*)"read_cc",
		     (char_1*)"input file is not opened");
  }

  // rewind the file pointer
  //
  rewind(fp_a);

  if (end_a > last_sample_a) {
    end_a = last_sample_a;
  }

  // make sure the end time is within the correct boundary
  //
  if (start_a > end_a) {
    return ISIP_FALSE;
  }

  int_4 sample = 0;
  if (start_a < 0) {

    // pad with zeros
    //
    for (int_4 i=start_a;i<0;i++) {
      buffer_a[sample++] = 0;
    }
    start_a = 0;
  }

  // seek to the starting of the first sample to process
  // 
  fseek(fp_a, start_a * SIGNAL_BYTES_PER_SAMPLE * num_chans_d, SEEK_SET);

  // calculate the number of samples to read
  //
  int_4 num_samples_to_read = (end_a - start_a) * num_chans_d;
  if (num_samples_to_read > (last_sample_a - start_a)) {
    num_samples_to_read = last_sample_a - start_a;
  }
  int_2* read_data = new int_2[num_samples_to_read];

  // read the data
  //
  samples_read_a = fread(read_data, sizeof(int_2), num_samples_to_read, fp_a);

  if (num_samples_to_read != samples_read_a) {
    error_handler_cc((char_1*)"read_cc",
		     (char_1*)"incorrect number of samples read");
  }
  //  int_4 read_value;

  for (int_4 i=0;i<num_samples_to_read;i++) {
    buffer_a[sample++] = (float_4)read_data[i];
  }

  if (last_sample_a < (end_a - start_a) * num_chans_d) {
    for (int_4 i=last_sample_a; i<(end_a-start_a)*num_chans_d; i++) {
      buffer_a[sample++] =0;
    }
  }

  if (debug_level_d > 2) {
    for (int_4 i=0;i<num_chans_d;i++) {
      for (int_4 j=i;j<sample;j+=num_chans_d) {
	fprintf(stdout, "chan %ld:: signal data [%ld] = %ld\n", i, j,
		(int_4)buffer_a[j]);
      }
    }
  }

  delete [] read_data;
  
  // exit gracefully
  //
  return ISIP_TRUE;
}