/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2022 by William WIlgus
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied. *
 ****************************************************************************/

#include "config.h"

#include <stddef.h>
#include <string.h>
#include "strtok_r.h"
/* strptokspn_r is a custom implementation of strtok_r that does NOT modify 
 *  the source string.
 *
 * strptokspn_r reads ptr as a series of zero or more tokens,
 *  and sep as delimiters of the tokens
 * The tokens can be separated by one or more of the delimiters
 * first call searches for the first token skipping over any leading delimiters.
 * Returns pointer to first token
 * Pointer *len contains the span to the first delimeter
 *  (this would be the resulting strlen had token actually been NULL terminated)
 * Pointer **end contains pointer to first character after the last delimeter
 *
 * When strptokspn_r is called with a ptr == NULL, the next token is read from
 * Pointer **end
 *
 * Note the returned token is NOT NULL terminated by the function as in strtok_r
 * However the caller can use ret[len+1] = '\0'; to emulate a call to strtok_r
*/

const char *strptokspn_r(const char *ptr, const char *sep, size_t *len, const char **end)
{
    *len = 0;
    if (!ptr)
        /* we got NULL input so then we get our last position instead */
        ptr = *end;

    /* pass all letters that are including in the separator string */
    while (*ptr && strchr(sep, *ptr))
        ++ptr;

    if (*ptr) {
        /* so this is where the next piece of string starts */
        const char *start = ptr;

        /* set the end pointer to the first byte after the start */
        *end = start + 1;

        /* scan through the string to find where it ends, it ends on a
           null byte or a character that exists in the separator string */
        while (**end && !strchr(sep, **end))
            ++*end;
        *len  = (*end - start) - 1; /* this would be the string len if there actually was a NULL */
        if (**end) { /* the end is not a null byte */
            ++*end;  /* advance last pointer to beyond the match */
        }

        return start; /* return the position where the string starts */
    }

    /* we ended up on a null byte, there are no more strings to find! */
    return NULL;
}

#if !defined(HAVE_STRTOK_R)
char * strtok_r(char *ptr, const char *sep, char **end)
{
    size_t len;
    char * ret = (char*) strptokspn_r((const char*)ptr, sep, &len, (const char**) end);
    if (ret)
        ret[len + 1] = '\0';
    return ret;
}
#endif