C: Parse empty tokens from a string with strtok

Question

My application produces strings like the one below. I need to parse values between the separator into individual values.

2342|2sd45|dswer|2342||5523|||3654|         


        

Answer 1

Below is the solution that is working for me now. Thanks to all of you who responded.

I am using LoadRunner. Hence, some unfamiliar commands, but I believe the flow can be understood easily enough.

char strAccInfo[1024], *p2;
int iLoop;

Action() {  //This value would come from the wrsp call in the actual script.
    lr_save_string("323|90||95|95|null|80|50|105|100|45","test_Param");

    //Store the parameter into a string - saves memory. 
    strcpy(strAccInfo,lr_eval_string("{test_Param}"));
    //Get the first instance of the separator "|" in the string
    p2 = (char *) strchr(strAccInfo,'|');

    //Start a loop - Set the max loop value to more than max expected.
    for (iLoop = 1;iLoop<200;iLoop++) { 

        //Save parameter names in sequence.
        lr_param_sprintf("Param_Name","Parameter_%d",iLoop);

        //Get the first instance of the separator "|" in the string (within the loop).
        p2 = (char *) strchr(strAccInfo,'|');           

        //Save the value for the parameters in sequence. 
        lr_save_var(strAccInfo,p2 - strAccInfo,0,lr_eval_string("{Param_Name}"));   

        //Save string after the first instance of p2, as strAccInfo - for looping.
        strcpy(strAccInfo,p2+1);

        //Start conditional loop for checking for last value in the string.
        if (strchr(strAccInfo,'|')==NULL) {
            lr_param_sprintf("Param_Name","Parameter_%d",iLoop+1);
            lr_save_string(strAccInfo,lr_eval_string("{Param_Name}"));
            iLoop = 200;    
        }
    }
}

Answer 2

Use something other than strtok. It's simply not intended to do what you're asking for. When I've needed this, I usually used strcspn or strpbrk and handled the rest of the tokeninzing myself. If you don't mind it modifying the input string like strtok, it should be pretty simple. At least right off, something like this seems as if it should work:

// Warning: untested code. Should really use something with a less-ugly interface.
char *tokenize(char *input, char const *delim) { 
    static char *current;    // just as ugly as strtok!
    char *pos, *ret;
    if (input != NULL)
        current = input;

    if (current == NULL)
        return current;

    ret = current;
    pos = strpbrk(current, delim);
    if (pos == NULL) 
        current = NULL;
    else {
        *pos = '\0';
        current = pos+1;
    }
    return ret;
}