examples/loadables/dirname.c

   1 /* dirname - return directory portion of pathname */
   2
   3 /* See Makefile for compilation details. */
   4
   5 /*
   6    Copyright (C) 1999-2009 Free Software Foundation, Inc.
   7
   8    This file is part of GNU Bush.
   9    Bush is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bush is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bush.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "config.h"
  24
  25 #if defined (HAVE_UNISTD_H)
  26 #  include <unistd.h>
  27 #endif
  28
  29 #include <stdio.h>
  30 #include "builtins.h"
  31 #include "shell.h"
  32 #include "common.h"
  33 #include "bushgetopt.h"
  34
  35 int
  36 dirname_builtin (list)
  37      WORD_LIST *list;
  38 {
  39   int slen;
  40   char *string;
  41
  42   if (no_options (list))
  43     return (EX_USAGE);
  44   list = loptend;
  45
  46   if (list == 0 || list->next)
  47     {
  48       builtin_usage ();
  49       return (EX_USAGE);
  50     }
  51
  52   string = list->word->word;
  53   slen = strlen (string);
  54
  55   /* Strip trailing slashes */
  56   while (slen > 0 && string[slen - 1] == '/')
  57     slen--;
  58
  59   /* (2) If string consists entirely of slash characters, string shall be
  60          set to a single slash character.  In this case, skip steps (3)
  61          through (8). */
  62   if (slen == 0)
  63     {
  64       fputs ("/\n", stdout);
  65       return (EXECUTION_SUCCESS);
  66     }
  67
  68   /* (3) If there are any trailing slash characters in string, they
  69          shall be removed. */
  70   string[slen] = '\0';
  71
  72   /* (4) If there are no slash characters remaining in string, string
  73          shall be set to a single period character.  In this case, skip
  74          steps (5) through (8).
  75
  76      (5) If there are any trailing nonslash characters in string,
  77          they shall be removed. */
  78
  79   while (--slen >= 0)
  80     if (string[slen] == '/')
  81       break;
  82
  83   if (slen < 0)
  84     {
  85       fputs (".\n", stdout);
  86       return (EXECUTION_SUCCESS);
  87     }
  88
  89   /* (7) If there are any trailing slash characters in string, they
  90          shall be removed. */
  91   while (--slen >= 0)
  92     if (string[slen] != '/')
  93       break;
  94   string[++slen] = '\0';
  95
  96   /* (8) If the remaining string is empty, string shall be set to a single
  97          slash character. */
  98   printf ("%s\n", (slen == 0) ? "/" : string);
  99   return (EXECUTION_SUCCESS);
 100 }
 101
 102 char *dirname_doc[] = {
 103         "Display directory portion of pathname.",
 104         "",
 105         "The STRING is converted to the name of the directory containing",
 106         "the filename corresponding to the last pathname component in STRING.",
 107         (char *)NULL
 108 };
 109
 110 /* The standard structure describing a builtin command.  bush keeps an array
 111    of these structures. */
 112 struct builtin dirname_struct = {
 113         "dirname",              /* builtin name */
 114         dirname_builtin,        /* function implementing the builtin */
 115         BUILTIN_ENABLED,        /* initial flags for builtin */
 116         dirname_doc,            /* array of long documentation strings. */
 117         "dirname string",       /* usage synopsis */
 118         0                       /* reserved for internal use */
 119 };