/* 

  * opendir.c --

  *

  *	This file provides dirent-style directory-reading procedures

  *	for V7 Unix systems that don't have such procedures.  The

  *	origin of this code is unclear, but it seems to have come

  *	originally from Larry Wall.

  *

  *

  * RCS: @(#) $Id: opendir.c,v 1.2 1998/09/14 18:39:44 stanton Exp $

  */

 #include "tclInt.h"

 #include "tclPort.h"

 #undef DIRSIZ

 #define DIRSIZ(dp) \

     ((sizeof (struct dirent) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))

 /*

  * open a directory.

  */

 DIR *

 opendir(name)

 char *name;

 {

 	register DIR *dirp;

 	register int fd;

 	char *myname;

 	myname = ((*name == '\0') ? "." : name);

 	if ((fd = open(myname, 0, 0)) == -1)

 		return NULL;

 	if ((dirp = (DIR *)ckalloc(sizeof(DIR))) == NULL) {

 		close (fd);

 		return NULL;

 	}

 	dirp->dd_fd = fd;

 	dirp->dd_loc = 0;

 	return dirp;

 }

 /*

  * read an old style directory entry and present it as a new one

  */

 #ifndef pyr

 #define	ODIRSIZ	14

 struct	olddirect {

 	ino_t	od_ino;

 	char	od_name[ODIRSIZ];

 };

 #else	/* a Pyramid in the ATT universe */

 #define	ODIRSIZ	248

 struct	olddirect {

 	long	od_ino;

 	short	od_fill1, od_fill2;

 	char	od_name[ODIRSIZ];

 };

 #endif

 /*

  * get next entry in a directory.

  */

 struct dirent *

 readdir(dirp)

 register DIR *dirp;

 {

 	register struct olddirect *dp;

 	static struct dirent dir;

 	for (;;) {

 		if (dirp->dd_loc == 0) {

 			dirp->dd_size = read(dirp->dd_fd, dirp->dd_buf,

 			    DIRBLKSIZ);

 			if (dirp->dd_size <= 0)

 				return NULL;

 		}

 		if (dirp->dd_loc >= dirp->dd_size) {

 			dirp->dd_loc = 0;

 			continue;

 		}

 		dp = (struct olddirect *)(dirp->dd_buf + dirp->dd_loc);

 		dirp->dd_loc += sizeof(struct olddirect);

 		if (dp->od_ino == 0)

 			continue;

 		dir.d_ino = dp->od_ino;

 		strncpy(dir.d_name, dp->od_name, ODIRSIZ);

 		dir.d_name[ODIRSIZ] = '\0'; /* insure null termination */

 		dir.d_namlen = strlen(dir.d_name);

 		dir.d_reclen = DIRSIZ(&dir);

 		return (&dir);

 	}

 }

 /*

  * close a directory.

  */

 void

 closedir(dirp)

 register DIR *dirp;

 {

 	close(dirp->dd_fd);

 	dirp->dd_fd = -1;

 	dirp->dd_loc = 0;

 	ckfree((char *) dirp);

 }