/* Copyright (c) 2016, Dennis Wölfing
 *
 * 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.
 */

/* libc/src/string/strtok.c
 * Splits a string into tokens.
 */

#include <string.h>

static char* next = NULL;

char* strtok(char* restrict str, const char* restrict separators) {
    if (!str) {
        str = next;
        if (!str) return NULL;
    }

    // Discard any leading separators.
    str = str + strspn(str, separators);
    if (!*str) return NULL;

    size_t tokenEnd = strcspn(str, separators);
    if (str[tokenEnd] == '\0') {
        next = NULL;
    } else {
        str[tokenEnd] = '\0';
        next = str + tokenEnd + 1;
    }

    return str;
}
