#include <stdio.h>
#include <stdlib.h>
#include <ext2fs/ext2_fs.h>

struct ext2_dir_entry_part {
        __u32   inode;                  /* Inode number */
        __u16   rec_len;                /* Directory entry length */
        __u8    name_len;               /* Name length */
        __u8    file_type;
} dep;

void usage()
{
  printf("read_dir_entry [dir entry filename] [dir entry size]\n");
}

int main(int argc, char **argv)
{

  struct ext2_dir_entry_2 de;
  char *filename = NULL;
  FILE *fp = NULL;
  int rtn = 0;
  int length = 0;
  int de_size = 0;
  int offset = 0;
  
  if (argc < 3)
  {
    printf("Too few parameters!\n");
    usage();
    exit(1); 
  }

  filename = argv[1];
  de_size  = atoi(argv[2]);

  fp = fopen(filename, "r"); 
  if (!fp)
  {
    printf("cannot open file: %s\n", filename);
    exit(1);
  }

  printf("  offset | inode number | rec_len | name_len | file_type | name\n");
  printf("=================================================================\n");

  while ( rtn = fread(&dep, sizeof(struct ext2_dir_entry_part), 1, fp) )
  {
    if (dep.rec_len <= 0)
    {
      fclose(fp);  
      exit(0);
    }

    fseek(fp, 0 - sizeof(struct ext2_dir_entry_part), SEEK_CUR);

    fread(&de, ((int)(dep.name_len + 3)/4)*4 + sizeof(struct ext2_dir_entry_part), 1, fp);
    de.name[de.name_len] = '\0';

    printf("%6d: %12d%12d%12d%12d  %s\n", offset, de.inode, de.rec_len, de.name_len, de.file_type, de.name);


    if (offset + de.rec_len > length)
    {
      length += de.rec_len;
    }

    offset += ((int)(de.name_len + 3)/4)*4 + sizeof(struct ext2_dir_entry_part);

    if (length >= de_size - sizeof(struct ext2_dir_entry_part))
    {
      fclose(fp);  
      exit(0);
    } 
  }
  
  fclose(fp);  
}