Parse string into argv/argc

Question

Is there a way in C to parse a piece of text and obtain values for argv and argc, as if the text had been passed to an application on the command line?

This doesn\'

Answer 1

My project requires breaking a string into argc and argv.

Found a pretty excellent code of Torek. But it alters the input buffer so I made some modifications to fit my needs.

I just put a little bit more to handle quote mixing when input in the command line so the behavior is more (not completely) like Linux Shell.

Note: This function doesn't edit the original string, so you can reuse the input buffer (error report,etc).

void remove_quote(char* input){
   //Implementing yourself to remove quotes so it would be completely like Linux shell
}
size_t cmd_param_split(char *buffer, char *argv[], size_t argv_max_size)
{
    char *p, *start_of_word;
    int c, i;
    enum states { DULL=0, IN_WORD, IN_STRING, QUOTE_DOUBLE,QUOTE_SINGLE } state = DULL;
    size_t argc = 0;
    int quote = 0;
    for (p = buffer; argc < argv_max_size && *p != '\0'; p++) {
        c = (unsigned char) *p;
        printf("processing %c, state = %d\n", c,state);
        switch (state) {
        case DULL:
            if (isspace(c)) {
                continue;
            }

            if (c == '"' ||c == '\'') {
                quote = c;
                state = IN_STRING;
                start_of_word = p + 1;
                continue;
            }
            state = IN_WORD;
            start_of_word = p;
            continue;

        case IN_STRING:
            if (c == '"' || c == '\'') {
                if (c!=quote)
                    continue;
                else
                    quote = 0;
                strncpy(argv[argc],start_of_word, p - start_of_word);
                remove_quote(argv[argc]);
                argc++;
                state = DULL;
            }
            continue;

        case IN_WORD:
            if(quote==0 && (c == '\"' ||c == '\''))
                quote = c;
            else if (quote == c)
                    quote = 0;

            if (isspace(c) && quote==0) {
                strncpy(argv[argc],start_of_word, p - start_of_word);
                remove_quote(argv[argc]);
                argc++;
                state = DULL;
            }
            continue;
        }
    }

    if (state != DULL && argc < argv_max_size){
        strncpy(argv[argc],start_of_word, p - start_of_word);
        remove_quote(argv[argc]);
        argc++;
    }

    if (quote){
        printf("WARNING: Quote is unbalanced. This could lead to unwanted-behavior\n");
        for(i = 0;i

Tested with below strings

 1. "1 2 3 \'3 4\"567\' \"bol\'obala\" 2x2=\"foo\""
   arg 0 = [1]
   arg 1 = [2]
   arg 2 = [3]
   arg 3 = [3 4"567]
   arg 4 = [bol'obala]
   arg 5 = [2x2="foo"]
 2. "./foo bar=\"Hanoi HoChiMinh\" exp='foo123 \"boo111' mixquote \"hanoi \'s\""
   arg 0 = [./foo]
   arg 1 = [bar="Hanoi HoChiMinh"]
   arg 2 = [exp='foo123 "boo111']
   arg 3 = [mixquote]
   arg 4 = [hanoi 's]

---

However, Linux shell would remove quotes, even in mixed case, as below when running from cmd line, tested in a RaspberryPi.

./foo bar="Hanoi HoChiMinh" exp='foo123 "boo111' mixquote "hanoi 's"
   arg 0 = [./foo]
   arg 1 = [bar=Hanoi HoChiMinh]
   arg 2 = [exp=foo123 "boo111]
   arg 3 = [mixquote]
   arg 4 = [hanoi 's]

So if you really want to mimic the whole Linux shell's behavior, just put a little bit more effort into removing quotes remove_quote() function as I leave blank above.