cosmopolitan/libc/str/strtok_r.c

55 lines
2.6 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/str/str.h"
/**
* Extracts non-empty tokens from string.
*
* @param s is mutated and should be NULL on subsequent calls
* @param sep is a NUL-terminated set of bytes to consider separators
* @param state tracks progress between calls
* @return pointer to next token or NULL for end
* @see strsep() which is similar
* @asyncsignalsafe
*/
char *strtok_r(char *s, const char *sep, char **state) {
size_t leadingseps, tokenlen;
if (!s) {
s = *state;
if (!s) {
return NULL;
}
}
leadingseps = strspn(s, sep);
s += leadingseps;
if (*s) {
tokenlen = strcspn(s, sep);
if (s[tokenlen]) {
s[tokenlen] = '\0';
*state = &s[tokenlen + 1];
return s;
} else if (tokenlen) {
s[tokenlen] = '\0';
*state = NULL;
return s;
}
}
return (*state = NULL);
}