strtok.c

含有完整TCP/IP PPP协议的嵌入式操作系统

/*
 * Copyright (C) 2004 by egnite Software GmbH. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL EGNITE
 * SOFTWARE GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * For additional information see http://www.ethernut.de/
 *
 *-
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * $Log: strtok.c,v $
 * Revision 1.1  2004/09/08 10:24:18  haraldkipp
 * Generic C string library added
 *
 */

#include <compiler.h>
#include <string.h>

/*!
 * \addtogroup xgCrtString
 */
/*@{*/

/*!
 * \brief Isolate sequential tokens in a NUL terminated string.
 *
 * The tokens are separated in the string by at least one of the
 * characters in the given separator string.
 *
 * The first time this function is called, the string should be 
 * specified. Subsequent calls, wishing to obtain further tokens
 * from the same string, should pass a null pointer instead.
 *
 * The separator string must be supplied each time, and may change 
 * between calls.
 *
 * \param s     Pointer to the string to separate.
 * \param delim Pointer to the separator string.
 *
 * \return A pointer to the beginning of each subsequent token
 *         in the string, after replacing the separator character 
 *         itself with a zero character. When no more tokens remain, 
 *         a null pointer is returned.
 */
char *strtok(char *s, CONST char *delim)
{
    static char *last;

    return strtok_r(s, delim, &last);
}

/*!
 * \brief Isolate sequential tokens in a NUL terminated string.
 * 
 * Similar to strtok(), but takes an explicit context argument 
 * and thus is reentrant.
 *
 * \param s     Pointer to the string to separate.
 * \param delim Pointer to the separator string.
 * \param last  Used to store the current search context.
 *
 * \return A pointer to the beginning of each subsequent token
 *         in the string, after replacing the separator character 
 *         itself with a zero character. When no more tokens remain, 
 *         a null pointer is returned.
 */
char *strtok_r(char *s, const char *delim, char **last)
{
    char *spanp;
    int c, sc;
    char *tok;


    if (s == NULL && (s = *last) == NULL)
        return (NULL);

    /*
     * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
     */
  cont:
    c = *s++;
    for (spanp = (char *) delim; (sc = *spanp++) != 0;) {
        if (c == sc)
            goto cont;
    }

    if (c == 0) {               /* no non-delimiter characters */
        *last = NULL;
        return (NULL);
    }
    tok = s - 1;

    /*
     * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
     * Note that delim must have one NUL; we stop if we see that, too.
     */
    for (;;) {
        c = *s++;
        spanp = (char *) delim;
        do {
            if ((sc = *spanp++) == c) {
                if (c == 0)
                    s = NULL;
                else
                    s[-1] = 0;
                *last = s;
                return (tok);
            }
        } while (sc != 0);
    }
    /* NOTREACHED */
}

/*@}*/