1 /* Concatenate two arbitrary file names.
3 Copyright (C) 1996-2007 Free Software Foundation, Inc.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
19 /* Written by Jim Meyering. */
24 #include "filenamecat.h"
32 #if ! HAVE_MEMPCPY && ! defined mempcpy
33 # define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N)))
36 /* Return the longest suffix of F that is a relative file name.
37 If it has no such suffix, return the empty string. */
40 longest_relative_suffix (char const *f)
42 for (f += FILE_SYSTEM_PREFIX_LEN (f); ISSLASH (*f); f++)
47 /* Concatenate two file name components, DIR and ABASE, in
48 newly-allocated storage and return the result.
49 The resulting file name F is such that the commands "ls F" and "(cd
50 DIR; ls BASE)" refer to the same file, where BASE is ABASE with any
51 file system prefixes and leading separators removed.
52 Arrange for a directory separator if necessary between DIR and BASE
53 in the result, removing any redundant separators.
54 In any case, if BASE_IN_RESULT is non-NULL, set
55 *BASE_IN_RESULT to point to the copy of ABASE in the returned
56 concatenation. However, if ABASE begins with more than one slash,
57 set *BASE_IN_RESULT to point to the sole corresponding slash that
58 is copied into the result buffer.
60 Return NULL if malloc fails. */
63 mfile_name_concat (char const *dir, char const *abase, char **base_in_result)
65 char const *dirbase = last_component (dir);
66 size_t dirbaselen = base_len (dirbase);
67 size_t dirlen = dirbase - dir + dirbaselen;
68 size_t needs_separator = (dirbaselen && ! ISSLASH (dirbase[dirbaselen - 1]));
70 char const *base = longest_relative_suffix (abase);
71 size_t baselen = strlen (base);
73 char *p_concat = malloc (dirlen + needs_separator + baselen + 1);
79 p = mempcpy (p_concat, dir, dirlen);
80 *p = DIRECTORY_SEPARATOR;
84 *base_in_result = p - IS_ABSOLUTE_FILE_NAME (abase);
86 p = mempcpy (p, base, baselen);
92 /* Just like mfile_name_concat, above, except, rather than
93 returning NULL upon malloc failure, here, we report the
94 "memory exhausted" condition and exit. */
97 file_name_concat (char const *dir, char const *abase, char **base_in_result)
99 char *p = mfile_name_concat (dir, abase, base_in_result);
105 #ifdef TEST_FILE_NAME_CONCAT
111 static char const *const tests[][3] =
121 {"a", "/", "a/"}, /* this might deserve a diagnostic */
122 {"/a", "/", "/a/"}, /* this might deserve a diagnostic */
127 for (i = 0; i < sizeof tests / sizeof tests[0]; i++)
129 char *base_in_result;
130 char const *const *t = tests[i];
131 char *res = file_name_concat (t[0], t[1], &base_in_result);
132 if (strcmp (res, t[2]) != 0)
134 printf ("got %s, expected %s\n", res, t[2]);
138 exit (fail ? EXIT_FAILURE : EXIT_SUCCESS);