/*-*- 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.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);
  }
}