strtok_s.c

Go to the documentation of this file.

/*------------------------------------------------------------------
 * strtok_s.c
 *
 * October 2008, Bo Berry
 *
 * Copyright (c) 2008-2011 by Cisco Systems, Inc
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *------------------------------------------------------------------
 */

#include "safeclib_private.h"
#include "safe_str_constraint.h"
#include "safe_str_lib.h"


char *
strtok_s(char * restrict dest, rsize_t * restrict dmax, const char * restrict src, char ** restrict ptr)
{

#ifndef STRTOK_DELIM_MAX_LEN
#define  STRTOK_DELIM_MAX_LEN  16
#endif

    const char *pt;
    char *ptoken;
    rsize_t dlen;
    rsize_t slen;

    if (dmax == NULL) {
        invoke_safe_str_constraint_handler("strtok_s: dmax is NULL",
                   NULL, ESNULLP);
        return (NULL);
    }

    if (*dmax == 0) {
        invoke_safe_str_constraint_handler("strtok_s: dmax is 0",
                   NULL, ESZEROL);
        return (NULL);
    }

    if (*dmax > RSIZE_MAX_STR) {
        invoke_safe_str_constraint_handler("strtok_s: dmax exceeds max",
                   NULL, ESLEMAX);
        return (NULL);
    }

    if (src == NULL) {
        invoke_safe_str_constraint_handler("strtok_s: src is null",
                   NULL, ESNULLP);
        return (NULL);
    }

    if (ptr == NULL) {
        invoke_safe_str_constraint_handler("strtok_s: ptr is null",
                   NULL, ESNULLP);
        return (NULL);
    }

    /* if the source was NULL, use the tokenizer context */
    if (dest == NULL) {
        dest = *ptr;
    }

    /*
     * scan dest for a delimiter
     */
    dlen = *dmax;
    ptoken = NULL;
    while (*dest != '\0' && !ptoken) {

        if (dlen == 0) {
            *ptr = NULL;
            invoke_safe_str_constraint_handler(
                      "strtok_s: dest is unterminated",
                       NULL, ESUNTERM);
            return (NULL);
        }

        /*
         * must scan the entire delimiter list
         * ISO should have included a delimiter string limit!!
         */
        slen = STRTOK_DELIM_MAX_LEN;
        pt = src;
        while (*pt != '\0') {

            if (slen == 0) {
                *ptr = NULL;
                invoke_safe_str_constraint_handler(
                          "strtok_s: src is unterminated",
                           NULL, ESUNTERM);
                return (NULL);
            }
            slen--;

            if (*dest == *pt) {
                ptoken = NULL;
                break;
            } else {
                pt++;
                ptoken = dest;
            }
        }
        dest++;
        dlen--;
    }

    /*
     * if the beginning of a token was not found, then no
     * need to continue the scan.
     */
    if (ptoken == NULL) {
        *dmax = dlen;
        return (ptoken);
    }

    /*
     * Now we need to locate the end of the token
     */
    while (*dest != '\0') {

        if (dlen == 0) {
            *ptr = NULL;
            invoke_safe_str_constraint_handler(
                      "strtok_s: dest is unterminated",
                       NULL, ESUNTERM);
            return (NULL);
        }

        slen = STRTOK_DELIM_MAX_LEN;
        pt = src;
        while (*pt != '\0') {

            if (slen == 0) {
                *ptr = NULL;
                invoke_safe_str_constraint_handler(
                          "strtok_s: src is unterminated",
                           NULL, ESUNTERM);
                return (NULL);
            }
            slen--;

            if (*dest == *pt) {
                /*
                 * found a delimiter, set to null
                 * and return context ptr to next char
                 */
                *dest = '\0';
                *ptr = (dest + 1);  /* return pointer for next scan */
                *dmax = dlen - 1;   /* account for the nulled delimiter */
                return (ptoken);
            } else {
                /*
                 * simply scanning through the delimiter string
                 */
                pt++;
            }
        }
        dest++;
        dlen--;
    }

    *dmax = dlen;
    return (ptoken);
}