cosmopolitan/libc/x/xjoinpaths.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ 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; version 2 of the License.                      │
│                                                                              │
│ 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, write to the Free Software                  │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
│ 02110-1301 USA                                                               │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/safemacros.internal.h"
#include "libc/str/str.h"
#include "libc/x/x.h"

/**
 * Joins paths, e.g.
 *
 *   "a"  + "b"  → "a/b"
 *   "a/" + "b"  → "a/b"
 *   "a"  + "b/" → "a/b/"
 *   "a"  + "/b" → "/b"
 *   "."  + "b"  → "b"
 *   ""   + "b"  → "b"
 *
 * @return newly allocated string of resulting path
 */
char *xjoinpaths(const char *path, const char *other) {
  if (!*other) {
    return xstrdup(path);
  } else if (!*path) {
    return xstrdup(other);
  } else if (startswith(other, "/") || !strcmp(path, ".")) {
    return xstrdup(other);
  } else if (endswith(path, "/")) {
    return xstrcat(path, other);
  } else {
    return xstrcat(path, '/', other);
  }
}