// Program: cpkdrawer
// Sung Sakong, PhD
// sung.sakong _at_ uni-due.de
// ver 0.5  4. June 2007
// CONTCAR multiplier for CPK drawing in VMD
// To remove the missing bond to the neighboring cell
// input: CONTCAR output: CONTCAR.multiple
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define LINESIZE 1024
#define MAXATOMTYPES 100

void main(void){

  FILE *contcar, *contout;
  int eachatom[MAXATOMTYPES];   // number of atoms per atom type
  int i, j, k, numatoms;
  char lineptr[LINESIZE];

  float cell[3][3];             // lattice vectors of the unit cell
  float lc;
  float crdx, crdy, crdz;

  contcar=fopen("CONTCAR", "r");
  contout=fopen("CONTCAR.multiple", "w");

  if (!contcar) {

    fclose(contcar);
    fclose(contout);
    printf("ERROR :: Cannot find CONTCAR!\n");
    return NULL;
  }

  fgets(lineptr, LINESIZE, contcar);
  fprintf(contout, "%s", lineptr);

  fscanf(contcar, "%f", &lc);
  fprintf(contout, "%12.8f", lc);

  for(i=0; i<4; i++){
    fgets(lineptr, LINESIZE, contcar);
    fprintf(contout, "%s", lineptr);
  }

  numatoms=0;
  fgets(lineptr, LINESIZE, contcar);
  for (i = 0; i < MAXATOMTYPES; i++) {
    char const *token = (i == 0 ? strtok(lineptr, " ") : strtok(NULL, " "));
    int const n = (token ? atoi(token) : -1);

    if (n <= 0) break;

    eachatom[i] = n;
    numatoms += n;
    fprintf(contout, "   %i", 4*n);
  }
  fprintf(contout, "\n");

 fgets(lineptr, LINESIZE, contcar);
 // Ignore selective tag-line, starting with either 's' or 'S'.
 if (lineptr[0]=='s' || lineptr[0]=='S') fgets(lineptr, LINESIZE, contcar);
 fprintf(contout, "Direct\n");

 // Check whether all coordinates are present in the file
 for (i = 0; i < numatoms; i++) {
   float coord;
   fgets(lineptr, LINESIZE, contcar);
   if (3 != sscanf(lineptr, "%f %f %f", &crdx, &crdy, &crdz)) {
     return NULL;
   }
   for(j=0; j<2; j++){
     for(k=0; k<2; k++){
       fprintf(contout, "%12.8f   %12.8f   %12.8f\n", crdx+j, crdy+k, crdz);
     }
   }
 }

  fclose(contcar);
  fclose(contout);

  return NULL;
}