cosmopolitan/libc/fmt/dirname.c

46 lines
2.3 KiB
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 │
│ │
│ 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/fmt/conv.h"
#include "libc/str/str.h"
#define ISDELIM(c) (c == '/' || c == '\\' || c == '.')
/**
* Returns directory portion of path.
* @param s is mutated
*/
char *dirname(char *s) {
size_t i, n;
if (!(n = strlen(s))) return s;
while (n && ISDELIM(s[n - 1])) --n;
if (n) {
while (n && !ISDELIM(s[n - 1])) --n;
if (n) {
while (n && ISDELIM(s[n - 1])) --n;
if (!n) ++n;
} else {
s[n++] = '.';
}
} else {
++n;
}
s[n] = '\0';
return s;
}