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/* Return the next element of a path.
Copyright (C) 1992 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Written by David MacKenzie <djm@gnu.ai.mit.edu>,
inspired by John P. Rouillard <rouilj@cs.umb.edu>. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#if defined(HAVE_STRING_H) || defined(STDC_HEADERS)
#include <string.h>
#else
#include <strings.h>
#ifndef strchr
#define strchr index
#endif
#endif
char *strdup ();
void free ();
/* Return the next element of a colon-separated path.
A null entry in the path is equivalent to "." (the current directory).
If NEW_PATH is non-NULL, set the path and return NULL.
If NEW_PATH is NULL, return the next item in the string, or
return NULL if there are no more elements. */
char *
next_element (new_path)
char *new_path;
{
static char *path = NULL; /* Freshly allocated copy of NEW_PATH. */
static char *end; /* Start of next element to return. */
static int final_colon; /* If zero, path didn't end with a colon. */
char *start; /* Start of path element to return. */
if (new_path)
{
if (path)
free (path);
end = path = strdup (new_path);
final_colon = 0;
return NULL;
}
if (*end == '\0')
{
if (final_colon)
{
final_colon = 0;
return ".";
}
return NULL;
}
start = end;
final_colon = 1; /* Maybe there will be one. */
end = strchr (start, ':');
if (end == start)
{
/* An empty path element. */
*end++ = '\0';
return ".";
}
else if (end == NULL)
{
/* The last path element. */
end = strchr (start, '\0');
final_colon = 0;
}
else
*end++ = '\0';
return start;
}
#ifdef TEST
int
main ()
{
char *p;
next_element (getenv ("PATH"));
while (p = next_element (NULL))
puts (p);
exit (0);
}
#endif /* TEST */
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