libc/string/dirname.c

   1 /*
   2  * Copyright (C) 2002     Manuel Novoa III
   3  * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
   4  *
   5  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
   6  */
   7
   8 #define __need_NULL
   9 #include <stddef.h>
  10 #include <libgen.h>
  11
  12 char *dirname(char *path)
  13 {
  14         static const char null_or_empty_or_noslash[] = ".";
  15         register char *s;
  16         register char *last;
  17         char *first;
  18
  19         last = s = path;
  20
  21         if (s != NULL) {
  22
  23         LOOP:
  24                 while (*s && (*s != '/')) ++s;
  25                 first = s;
  26                 while (*s == '/') ++s;
  27                 if (*s) {
  28                         last = first;
  29                         goto LOOP;
  30                 }
  31
  32                 if (last == path) {
  33                         if (*last != '/') {
  34                                 goto DOT;
  35                         }
  36                         if ((*++last == '/') && (last[1] == 0)) {
  37                                 ++last;
  38                         }
  39                 }
  40                 *last = 0;
  41                 return path;
  42         }
  43  DOT:
  44         return (char *) null_or_empty_or_noslash;
  45 }