nftw command line version

POSIX C function nftw(p) walks directory tree and reports data on files.

Its just do something like piping of output of following line:

find  | xargs stat

Below is 100+ lines C++ version of previous line.

g++ exnftw.cpp -o nftw
------------%<---------------
#include <ftw.h>
#include <stdio.h>
#include <map>
#include <string>

/* 2008, Author: R.Gritsulyak 
 * public domain; 
 * g++ exnftw.cpp -o nftw
 * no warranty for this utility. 
 * patch sendto: roman.gritsulyak@gmail.com
 *
 * example for:
 int nftw(const char *path, int (*fn)(const char *,
 const struct stat *, int, struct FTW *), int depth, int flags);
*/

int fnfn(const char *path, const struct stat *ptr,int type, struct FTW *pft)
{
 const char *sflag;
 switch (type)
 {
  case FTW_NS:
   sflag="FTW_NS: no permission: exit by error;";
   break;
  case FTW_DNR:
   sflag="FTW_DNR: can not read dir; no further reads in;";
   break;
  case FTW_SLN:
   sflag="FTW_SLN: symbolic link on unknown path;";
   break;
  case FTW_SL:
   sflag="FTW_SL: should detect if only FTW_SL set;";
   break;
  case FTW_DP:
   sflag="FTW_DP: directory; we have been in subdirs;";
   break;
  case FTW_D:
   sflag="FTW_D: directory;";
   break;
  case FTW_F:
   sflag="FTW_F: file;";
   break;
  default: 
   sflag="unknown:";
 }

 printf("path=%s\ntype=%s\n",path,sflag);
 printf("stat.st_ino=%d\n",ptr->st_ino);
        printf("stat.st_mode=%o\n",ptr->st_mode);
        printf("stat.st_nlink=%d\n",ptr->st_nlink);
        printf("stat.st_uid=0%o\n",ptr->st_dev);
        printf("stat.st_gid=0%o\n",ptr->st_gid);
        printf("stat.st_rdev=%d\n",ptr->st_rdev);
        printf("stat.st_size=%d\n",ptr->st_size);
        printf("stat.st_blksize=%u\n",ptr->st_blksize);
        printf("stat.st_blocks=%u\n",ptr->st_blocks);
        printf("stat.st_atime=%d\n",ptr->st_atime);
        printf("stat.st_mtime=%d\n",ptr->st_mtime);
        printf("stat.st_ctime=%d\n",ptr->st_ctime);
  printf("FTW.base=%d\nFTW.level=%d\n",pft->base,pft->level); 
 return 0;
}


struct chvali
{
std::string ch;
int vali;
}; 

const int FLAGS=4;

chvali stra[] = {
{"FTW_CHDIR",FTW_CHDIR},
{"FTW_DEPTH",FTW_DEPTH},
{"FTW_MOUNT",FTW_MOUNT},
{"FTW_PHYS",FTW_PHYS}
}; 

int usage()
{
 fprintf(stderr,"Usage: nftw FLAG1 FLAG2 .. FLAGn depth path\n");
 fprintf(stderr,"FLAGx is FTW_CHDIR, FTW_DEPTH, FTW_MOUNT, FTW_PHYS\n");
 fprintf(stderr,"depth # number of file descriptors to use\n");
 fprintf(stderr,"man p nftw # for further details on args\n"); 
 return 0;
} 

int main(int argc, char ** argv)
{
 char * inipath; 
 int i;
 int idepth;
 int iflags;
 int curflag;

 std::map<std::string,int> chv;

 for(i=0;i<FLAGS;i++)
  chv[stra[i].ch]=stra[i].vali;  

 if (argc < 3)
 {
  exit(1);
 }

 iflags = 0;
 std::map<std::string,int> iter;

 for(i=1; i<argc-2; i++)
 {
     if( chv.find(argv[i]) != chv.end() )
  iflags = iflags | chv[argv[i]];   
            else
  {
  fprintf(stderr, "Wrong argument type:%s\n",argv[i]);
  usage();
  exit(-1);
  }
 }

 inipath = argv[argc-1];
 char *dum;
 idepth = strtol(argv[argc-2], &dum, 0);
  
 if(nftw(inipath,fnfn,idepth,iflags) != 0)
 {
  perror("nftw");
  exit(2);
 }

 exit(0);
}

related ftw example