/*
 * @(#) dirtree.c - Recursive directory lister.
 * (c) 1996 Ivan Maidanski <ivmai@chat.ru> http://ivmai.chat.ru
 * Freeware program source. All rights reserved.
 **
 * Language: ANSI C
 * Tested with: Watcom C16 v10.0
 * Last modified: 1996-07-11 16:50:00 GMT+04:00
 */

#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <direct.h> /* <dirent.h> */

#define DRIVESPEC ':' /* Drive letter delimiter in MS-DOS */
#define DELIMITER '\\' /* MS-DOS style of directory names delimiter */

#ifndef PATH_MAX
#define PATH_MAX FILENAME_MAX /* MS-DOS style of path name length */
#endif

#define SPECIALCH '.' /* for '.' and '..' files */

void putnspace(int n)
{
 while (n--)
  putchar(' ');
}

void printerror(char *errmsg,char *path)
{
 fputs("Error: ",stderr);
 fputs(errmsg,stderr);
 fputs(" - ",stderr);
 fputs(path,stderr);
 fputs("\n",stderr);
}

int checkfilename(char *path)
{
 struct stat info;
 char *pc=strchr(path,'\0');
 if (path==pc || *(pc-1)==DRIVESPEC)
 {
  *pc=DELIMITER;
  *(pc+1)='\0';
 }
 if (stat(path,&info)<0)
  return (0);
 if (!*pc && S_ISDIR(info.st_mode))
 {
  *pc=DELIMITER;
  *(pc+1)='\0';
 }
 return (1);
}

int findnextname(char *path)
{
 DIR *dirp;
 struct dirent *entry;
 char savech,*pc=strchr(path,'\0');
 char *name;
 do pc--;
  while (*pc!=DELIMITER);
 name=pc+1;
 if (path==pc || *(pc-1)==DRIVESPEC)
  pc++;
 savech=*pc;
 *pc='\0';
 if (!(dirp=opendir(path)))
 {
  printerror("Cannot open directory",path);
  return (0);
 }
 *pc=savech;
 if (*name)
 {
  do entry=readdir(dirp);
   while (entry && strcmp(&entry->d_name[0],name));
  if (!entry)
  {
   printerror("Cannot find file",path);
   closedir (dirp);
   *pc='\0';
   return (0);
  }
 }
 do entry=readdir(dirp);
  while (entry && entry->d_name[0]==SPECIALCH);
 if (!entry)
 {
  closedir (dirp);
  *pc='\0';
  return (0);
 }
 strcpy(name,&entry->d_name[0]);
 closedir(dirp);
 return (1);
}

void printtree(char *path)
{
 int level=0;
 do
 {
  if (*(strchr(path,'\0')-1)==DELIMITER)
   level++;
  while (level && !findnextname(path))
   level--;
  if (level)
  {
   char *name;
   checkfilename(path);
   name=strchr(path,'\0')-1;
   while (*(name-1)!=DELIMITER)
    name--;
   putnspace(level);
   puts(name);
  }
 } while (level);
}

int main(int argc,char *argv[])
{
 static char path[PATH_MAX+2];
 if (argc!=2)
  puts("Directory Tree.\n"
       "Usage:\n"
       " DIRTREE pathname [ > filelist ]");
 if (argc>2)
 {
  fputs("Error: Too many arguments!\n",stderr);
  return (2);
 }
 if (argc==2)
  if (strlen(argv[1])>PATH_MAX)
  {
   fputs("Error: Path name too long!\n",stderr);
   return (2);
  }
  else if (argv[1][0]!='\0')
  {
   char *pc;
   strcpy(&path[0],argv[1]);
   if (*(pc=strchr(&path[0],'\0')-1)==DELIMITER)
    *pc='\0';
   if (!checkfilename(path))
   {
    printerror("Invalid file name",path);
    return (1);
   }
   puts(path);
   printtree(&path[0]);
  }
 return (0);
}