#include <string.h>
#include <stdio.h>
#include "TFile.h"
#include "TTree.h"
#include "TString.h"
#include <iostream>

struct Header_t {
   char           event_header[4];
   unsigned int   serial_number;
   unsigned short year;
   unsigned short month;
   unsigned short day;
   unsigned short hour;
   unsigned short minute;
   unsigned short second;
   unsigned short millisecond;
   unsigned short reserved1;
   float time[1024];
};

struct Waveform_t {
   char           chn1_header[4];
   unsigned short chn1[1024];
   char           chn2_header[4];
   unsigned short chn2[1024];
   char           chn3_header[4];
   unsigned short chn3[1024];
   char           chn4_header[4];
   unsigned short chn4[1024];
};

void decode(char *filename) {
   Header_t header;
   Waveform_t waveform;
   Double_t t[1024], chn1[1024], chn2[1024], chn3[1024], chn4[1024];
   Int_t n;

   // open the binary waveform file
   FILE *f = fopen(Form("%s.dat", filename), "r");

   //open the root file
   TFile *outfile = new TFile(Form("%s.root", filename), "RECREATE");
   
   // define the rec tree
   TTree *rec = new TTree("rec","rec");
   rec->Branch("t", &t   ,"t[1024]/D");  
   rec->Branch("chn1", &chn1 ,"chn1[1024]/D");
   rec->Branch("chn2", &chn2 ,"chn2[1024]/D");
   rec->Branch("chn3", &chn3 ,"chn3[1024]/D");
   rec->Branch("chn4", &chn4 ,"chn4[1024]/D");
  
   // loop over all events in data file
   for (n=0 ; fread(&header, sizeof(header), 1, f) > 0; n++) {

      // decode time      
      for (Int_t i=0; i<1024; i++)
         t[i] = (Double_t) header.time[i];
      
      fread(&waveform, sizeof(waveform), 1, f);
      
      // decode amplitudes in mV
      for (Int_t i=0; i<1024; i++) {
         chn1[i] = (Double_t) ((waveform.chn1[i]) / 65535. - 0.5) * 1000;   
         chn2[i] = (Double_t) ((waveform.chn2[i]) / 65535. - 0.5) * 1000;   
         chn3[i] = (Double_t) ((waveform.chn3[i]) / 65535. - 0.5) * 1000;   
         chn4[i] = (Double_t) ((waveform.chn4[i]) / 65535. - 0.5) * 1000;   
      }
      rec->Fill();
   }
   
   // draw channel #4
   rec->Draw("chn4:t");
   
   // print number of events
   cout<<n<<" events processed"<<endl;
   cout<<"\""<<Form("%s.root", filename)<<"\" written"<<endl;
   
   // save and close root file
   rec->Write();
   outfile->Close();
}