text: /*-*- 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                              │
  │                                                                              │
  │ Permission to use, copy, modify, and/or distribute this software for         │
  │ any purpose with or without fee is hereby granted, provided that the         │
  │ above copyright notice and this permission notice appear in all copies.      │
  │                                                                              │
  │ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
  │ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
  │ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
  │ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
  │ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
  │ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
  │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
  │ PERFORMANCE OF THIS SOFTWARE.                                                │
  ╚─────────────────────────────────────────────────────────────────────────────*/
  #include "libc/bits/safemacros.internal.h"
  #include "libc/str/path.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 (_isabspath(other) || !strcmp(path, ".")) {
      return xstrdup(other);
    } else if (endswith(path, "/")) {
      return xstrcat(path, other);
    } else {
      return xstrcat(path, '/', other);
    }
  }
  