/*
  sig2wav.cpp - AAEL .sig format to MIT WFDB-compatible .wav format conversion application
  
  Written for:
    Ann Arbor Electrogram Libraries
    http://www.electrogram.com
  
  Written by:
    Syed Mohammad
    Zethus Enterprises, LLC
    P.O. Box 130677, Ann Arbor, MI 48113
    email: syed.mohammad@zethus.com
    http://www.zethus.com

  (c)2007 Ann Arbor Electrogram Libraries
*/

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

enum { TEXT, BINARY };

void printSizeOf() {
  cout << "sizeof(char) = " << sizeof(char) << endl;
  cout << "sizeof(short) = " << sizeof(short) << endl;
  cout << "sizeof(long) = " << sizeof(long) << endl;
  cout << "sizeof(int) = " << sizeof(int) << endl;
  cout << "sizeof(float) = " << sizeof(float) << endl;
  cout << "sizeof(double) = " << sizeof(double) << endl;
}//printSizeOf

int out16(ofstream &ofile, short x) {
    ofile.put(x & 0xff        );
    ofile.put((x >> 8) & 0xff );
    return(2);
}//out16

int out32(ofstream &ofile, long x) {
    ofile.put(x & 0xff        );
    ofile.put((x >> 8) & 0xff );
    ofile.put((x >> 16) & 0xff);
    ofile.put((x >> 24) & 0xff);
    return(4);
}//out32

int sig2txt(ifstream::pos_type size, char * memblock, string name) {
  int offset = 326;
  short chan = memblock[0];
  int freq;
  memcpy(&freq, &memblock[2], 4);	
  cout << "channels: " << chan << "\tfrequency: " << freq << " hz" << endl;

  ofstream ofile((name + ".txt").c_str(), ios::out);
  short val;
  do {
    for (int i = 0; i < chan; i++)	{
      memcpy(&val, &memblock[offset+(i*2)], 2);	
      ofile  << val << "\t";
    }  
    ofile << endl;
  } while ((offset+=(chan*2)) < size);

  ofile.close();
  return size;
} //sig2txt

int sig2wav(ifstream::pos_type size, char * memblock, string name)
{
  int offset = 326;
  short chan = memblock[0];
  int freq;
  memcpy(&freq, &memblock[2], 4);	
  cout << "channels: " << chan << "\tfrequency: " << freq << " hz" << endl;
  
  ofstream ofile((name + ".wav").c_str(), ios::out|ios::binary);
  short val;

  //44byte header (0x00-0x2C)
  //(0x2C onwards = data)

  //[Header chunk]  
  ofile.write("RIFF", 4);
  out32(ofile, ((int)size - 326) + 36);  //size of remaining file
  ofile.write("WAVE", 4);
  
  //[Format chunk]
  ofile.write("fmt ", 4);
  out32(ofile, 16);    //16 (format chunk length in bytes)  
  out16(ofile, 1);     //1 (format tag, no compresion)
  out16(ofile, chan);     //number of signals
  out32(ofile, freq);  //sampling frequency in Hz
  out32(ofile, freq*chan*2); //bytes per second
  out16(ofile, chan*2);    //frame size (chan * 2 bytes/chan)
  out16(ofile, 12);    //bits per sample (actual bits per sample)

  //[Data chunk]
  ofile.write("data", 4);
  out32(ofile, ((int)size - 326));

  ofile.write(&memblock[326], (ifstream::pos_type)((int)size-326));

  ofile.close();
  return size;
} //sig2wav

void printHelp() {
  cout << "sig2wav usage:" << endl << endl
       << "  to convert filename.sig to MIT WFDB-compatible WAV format filename.wav:" << endl
       << "    sig2wav filename.sig" << endl << endl
       << "  to convert filename.sig to tab-delimited TXT format filename.txt:" << endl
       << "    sig2wav -t filename.sig" << endl << endl
       << "  to display this help screen:" << endl
       << "    sig2wav -h" << endl
       << endl 
       << "  (c)2007 Ann Arbor Electrogram Libraries http://www.electrogram.com" << endl;
}//printHelp

string getName(char * argv) {
  string name = string(argv);
  return(name.substr(0,name.find_last_of(".",name.size())));
}//getName

int main (int argc, char ** argv) {

  ifstream::pos_type size;
  char * memblock;
  int outputMode = BINARY; //default to Binary output
  string name;

  if (argc < 2) {
    printHelp();
    return 0;
  }
  
  if (!strcmp(argv[1], "-s") | !strcmp(argv[1], "-S")) {
    printSizeOf();
    return 0;
  }

  if (!strcmp(argv[1], "-h") | !strcmp(argv[1], "-H") | !strcmp(argv[1], "-?") | !strcmp(argv[1], "?")) {
    printHelp();
    return 0;
  }

  ifstream file;

  if (!strcmp(argv[1], "-t") | !strcmp(argv[1], "-T")) {
    outputMode = TEXT;
    if (argc < 3) {
      printHelp();
      return 0;
    }
    file.open(argv[2], ios::in|ios::binary|ios::ate);
    name = getName(argv[2]);
  }
  else {
    file.open(argv[1], ios::in|ios::binary|ios::ate);
    name = getName(argv[1]);
  }  
  
  cout << "processing file " << ((outputMode == TEXT) ? argv[2] : argv[1]) << endl;  

  if (file.is_open())
  {
    size = file.tellg();
    memblock = new char [size];
    file.seekg (0, ios::beg);
    file.read (memblock, size);
    file.close();
    cout << size << " bytes loaded in memory" << endl;
    cout << ((outputMode == TEXT) ? sig2txt(size, memblock, name) : sig2wav(size, memblock, name)) << " bytes processed" << endl;
    delete[] memblock;
  }
  else cout << "unable to open file" << endl;
  return 0;
}//main