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/* Concatenate two arbitrary file names.
Copyright (C) 1996-2007, 2009-2016 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 3 of the License, 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, see <http://www.gnu.org/licenses/>. */
/* Written by Jim Meyering. */
#include <config.h>
/* Specification. */
#include "filenamecat.h"
#include <stdlib.h>
#include <string.h>
#include "dirname.h"
#if ! HAVE_MEMPCPY && ! defined mempcpy
# define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N)))
#endif
/* Return the longest suffix of F that is a relative file name.
If it has no such suffix, return the empty string. */
static char const * _GL_ATTRIBUTE_PURE
longest_relative_suffix (char const *f)
{
for (f += FILE_SYSTEM_PREFIX_LEN (f); ISSLASH (*f); f++)
continue;
return f;
}
/* Concatenate two file name components, DIR and ABASE, in
newly-allocated storage and return the result.
The resulting file name F is such that the commands "ls F" and "(cd
DIR; ls BASE)" refer to the same file, where BASE is ABASE with any
file system prefixes and leading separators removed.
Arrange for a directory separator if necessary between DIR and BASE
in the result, removing any redundant separators.
In any case, if BASE_IN_RESULT is non-NULL, set
*BASE_IN_RESULT to point to the copy of ABASE in the returned
concatenation. However, if ABASE begins with more than one slash,
set *BASE_IN_RESULT to point to the sole corresponding slash that
is copied into the result buffer.
Return NULL if malloc fails. */
char *
mfile_name_concat (char const *dir, char const *abase, char **base_in_result)
{
char const *dirbase = last_component (dir);
size_t dirbaselen = base_len (dirbase);
size_t dirlen = dirbase - dir + dirbaselen;
size_t needs_separator = (dirbaselen && ! ISSLASH (dirbase[dirbaselen - 1]));
char const *base = longest_relative_suffix (abase);
size_t baselen = strlen (base);
char *p_concat = malloc (dirlen + needs_separator + baselen + 1);
char *p;
if (p_concat == NULL)
return NULL;
p = mempcpy (p_concat, dir, dirlen);
*p = DIRECTORY_SEPARATOR;
p += needs_separator;
if (base_in_result)
*base_in_result = p - IS_ABSOLUTE_FILE_NAME (abase);
p = mempcpy (p, base, baselen);
*p = '\0';
return p_concat;
}
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