diff options
Diffstat (limited to 'gl/lib/filenamecat-lgpl.c')
-rw-r--r-- | gl/lib/filenamecat-lgpl.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/gl/lib/filenamecat-lgpl.c b/gl/lib/filenamecat-lgpl.c new file mode 100644 index 0000000..98b105a --- /dev/null +++ b/gl/lib/filenamecat-lgpl.c @@ -0,0 +1,87 @@ +/* Concatenate two arbitrary file names. + + Copyright (C) 1996-2007, 2009-2019 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 <https://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 + +/* Concatenate two file name components, DIR and BASE, 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. If necessary, put + a separator between DIR and BASE in the result. Typically this + separator is "/", but in rare cases it might be ".". + In any case, if BASE_IN_RESULT is non-NULL, set + *BASE_IN_RESULT to point to the copy of BASE at the end of the + returned concatenation. + + Return NULL if malloc fails. */ + +char * +mfile_name_concat (char const *dir, char const *base, char **base_in_result) +{ + char const *dirbase = last_component (dir); + size_t dirbaselen = base_len (dirbase); + size_t dirlen = dirbase - dir + dirbaselen; + size_t baselen = strlen (base); + char sep = '\0'; + if (dirbaselen) + { + /* DIR is not a file system root, so separate with / if needed. */ + if (! ISSLASH (dir[dirlen - 1]) && ! ISSLASH (*base)) + sep = '/'; + } + else if (ISSLASH (*base)) + { + /* DIR is a file system root and BASE begins with a slash, so + separate with ".". For example, if DIR is "/" and BASE is + "/foo" then return "/./foo", as "//foo" would be wrong on + some POSIX systems. A fancier algorithm could omit "." in + some cases but is not worth the trouble. */ + sep = '.'; + } + + char *p_concat = malloc (dirlen + (sep != '\0') + baselen + 1); + char *p; + + if (p_concat == NULL) + return NULL; + + p = mempcpy (p_concat, dir, dirlen); + *p = sep; + p += sep != '\0'; + + if (base_in_result) + *base_in_result = p; + + p = mempcpy (p, base, baselen); + *p = '\0'; + + return p_concat; +} |