#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <dirent.h>

int istable11char(char c) {
  return (('0' <= c && c <= '9') || ('A' <= c && c <= 'Z') || ('_' == c)) ;
}

int gooddir(const struct dirent *testd) {
  char *filname = testd->d_name ;
  return(isdigit(filname[0]) &&
	 filname[0] != '0' &&
	 isdigit(filname[1]) &&
	 isdigit(filname[2]) &&
	 istable11char(filname[3]) &&
	 istable11char(filname[4]) &&
	 istable11char(filname[5]) &&
	 istable11char(filname[6]) &&
	 istable11char(filname[7]) &&
	 filname[8] == '\0') ;
}

int goodfile(const struct dirent *testd) {
  char *filname = testd->d_name ;
  return(istable11char(filname[0]) &&
	 istable11char(filname[1]) &&
	 istable11char(filname[2]) &&
	 istable11char(filname[3]) &&
	 isdigit(filname[4]) &&
	 isdigit(filname[5]) &&
	 isdigit(filname[6]) &&
	 isdigit(filname[7]) &&
	 (filname[4] != '0' ||
	  filname[5] != '0' ||
	  filname[6] != '0' ||
	  filname[7] != '0') &&
	 filname[8] == '.' &&
	 istable11char(filname[9]) &&
	 istable11char(filname[10]) &&
	 istable11char(filname[11]) &&
	 filname[12] == '\0' ) ;
}

int objectsort(const void *A, const void *B) {
  int res ;
  struct dirent *Adir, *Bdir ;
  Adir = *((struct dirent **)A );
  Bdir = *((struct dirent **)B );
  res = strncmp(&(Adir->d_name[4]), &(Bdir->d_name[4]), 4) ;
  if (!res)
    res = strcoll(Adir->d_name, Bdir->d_name) ;
  return res ;
}

int main(int argc, char *argv[]) {
  int numdirs, dirp ;
  struct dirent **dirlist ;
  numdirs = scandir("DCIM", &dirlist, gooddir, alphasort) ;
  for (dirp=0; dirp<numdirs; ++dirp) {
    struct dirent **fillist ;
    int numfils, filp ;
    char dcfdir[14], objname[5] ;
    strcpy(objname, "CSCI") ;
    fprintf(stdout, "DCF directory: %s\n", dirlist[dirp]->d_name) ;
    sprintf(dcfdir, "DCIM/%s", dirlist[dirp]->d_name) ;
    numfils = scandir(dcfdir, &fillist, goodfile, objectsort) ;
    for (filp = 0; filp < numfils; ++filp) {
      if(strncmp(&fillist[filp]->d_name[4], objname, 4)) {
	strncpy(objname, &fillist[filp]->d_name[4], 4) ;
	fprintf(stdout, "   DCF Object name: %4s\n", objname) ;
      }
      fprintf(stdout, "      DCF Filename: %s\n", fillist[filp]->d_name) ;
    }
    fputc('\n', stdout) ;
  }
}