Test multithreaded Open Babel application

multithread.cpp

#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <process.h>

#ifdef WIN32
#define USING_OBDLL
#endif

#include <openbabel/babelconfig.h>
#include <openbabel/obconversion.h>
#include <openbabel/mol.h>
#include <openbabel/locale.h>

#define MAX_THREADS  2

HANDLE  hScreenMutex;                // "Screen update" mutex
int     ThreadNr;                    // Number of threads started 

typedef std::vector<std::string> SmiData;

struct ThreadData {
  ThreadData(unsigned int _id, SmiData *_smis) : id(_id), smis(_smis) {};
  ~ThreadData() {
    delete smis;
  }
  unsigned int id;
  SmiData* smis;
};

using namespace OpenBabel;

void DoSearch(void* threadData)
{
  ThreadData* tdata = (ThreadData*)threadData;

  WaitForSingleObject(hScreenMutex, INFINITE);
  printf("Starting thread %d\n", tdata->id);
  ReleaseMutex(hScreenMutex);

  OBConversion conv;
  conv.SetInFormat("smi");
  for (int i = 0; i < tdata->smis->size(); ++i) {
    OBMol mol;
    conv.ReadString(&mol, (*tdata->smis)[i].c_str());
    std::string noel = conv.WriteString(&mol);
  }

  WaitForSingleObject(hScreenMutex, INFINITE);
  printf("Finishing thread %d\n", tdata->id);
  ReleaseMutex(hScreenMutex);

  delete tdata;
  InterlockedDecrement((LONG*)&ThreadNr);
}

void StartThreads(void) // Dispatch and count threads.
{
  obErrorLog.StopLogging(); // not thread-safe
  OBConversion conv;
  conv.SetInFormat("smi"); // loading of plugins not thread-safe so do it here
  OBMol mol;
  conv.ReadString(&mol, "C"); // Init() of global typers not thread-safe so do it here
  obLocale.SetLocale(); // Prevent Open Babel later get/setting the locale by doing it here

  const unsigned int chunksize = 10;

  std::ifstream inp("C:\\Tools\\openbabel\\mySmilesValence\\build\\chembl_20_subset.smi");
  std::string smi;
  unsigned int i = 0;
  unsigned int threadid = 0;
  SmiData* data = new SmiData(chunksize);
  while (std::getline(inp, smi))
  {
    (*data)[i] = smi;
    if (i == chunksize - 1) {
      // block on thread finishing
      while (ThreadNr >= MAX_THREADS) {
        Sleep(50);
      }
      InterlockedIncrement((LONG*)&ThreadNr);
      ThreadData *td = new ThreadData(threadid++, data);
      _beginthread(DoSearch, 0, td);
      i = 0;
      data = new SmiData(chunksize);
    }
    else
      i++;
  }

  while (ThreadNr > 0) {
    Sleep(250);
  }

  obLocale.RestoreLocale(); // Undo the SetLocale() above

}

int main() // Thread One 
{
  // Create the mutexes and reset thread count.
  hScreenMutex = CreateMutex(NULL, FALSE, NULL);  // Cleared 
  ThreadNr = 0;

  StartThreads();

  // All threads done. Clean up handles.
  CloseHandle(hScreenMutex);
  getchar();
}