argv.h

#ifndef ARGV_H
#define ARGV_H

static char* decode_string(char* str)
{
    size_t str_len = strlen(str), i = 0;
    char* dest = str;

    if ((str_len > 1) && ((*str == '\"') || (*str == '\'')) && (str[str_len - 1] == *str)) {
        memmove(str, str + 1, str_len - 2);
        str[str_len - 2] = 0;
    }

    while (*str) {
        if (*str == '\\') {
            str++;
        }
        dest[i++] = *str++;
    }
    dest[i] = 0;
    return (dest);
}

static char* find_next_match(char* str, char match_char)
{
    char* pos = 0;

    while (*str) {
        if (*str == match_char) {
            pos = str;
            break;
        }
        if (*str == '\\') {
            if (str[1]) {
                str++;
            } else {
                break;
            }
        }
        str++;
    }
    return (pos);
}

static char* get_param(char* str)
{
    static char* pos = 0;
    char* token = 0;

    if (str) // Start a new string?
    {
        pos = str;
    }

    if (pos) {
        // Skip delimiters
        while (*pos == ' ') {
            pos++;
        }
        if (*pos) {
            token = pos;

            // Skip non-delimiters
            while (*pos && (*pos != ' ')) {
                // Skip quoted characters
                if ((*pos == '\"') || (*pos == '\'')) {
                    char* match_pos = 0;
                    if ((match_pos = find_next_match(pos + 1, *pos))) {
                        pos = match_pos;
                    }
                }
                // Skip escaped spaces
                if (*pos == '\\') {
                    pos++;
                }
                pos++;
            }
            if (*pos) {
                *pos++ = '\0';
            }
        }
    }
    return (token);
}

static size_t count_param(char* str)
{
    size_t i = 0;

    while (*str) {
        // Skip delimiters
        while (*str == ' ') {
            str++;
        }
        // Skip non-delimiters
        while (*str && (*str != ' ')) {
            // Skip quoted characters
            if ((*str == '\"') || (*str == '\'')) {
                char* match_str = 0;
                if ((match_str = find_next_match(str + 1, *str))) {
                    str = match_str;
                }
            }
            // Skip escaped spaces
            if (*str == '\\') {
                str++;
            }
            str++;
        }
        i++;
    }
    return (i);
}

static char** build_argv(char* str)
{
    size_t argc = count_param(str);
    char** argv = (char**)malloc(sizeof(char*) * (argc + 1));

    if (argv) {
        char *p, **argp = argv;
        for (p = get_param(str); p; p = get_param(0), argp++) {
            *argp = decode_string(p);
        }
        *argp = 0;
        return (argv);
    }
    return (0);
}

#endif