[ECOS] RedBoot gets() implimentation question

Grant Edwards grante@visi.com
Thu Jan 18 14:12:00 GMT 2001


If you don't mind, I've got a couple questions about the
implimentation of gets() in RedBoot:

========================================================================
gets(char *buf, int buflen, int timeout)
{
[...]

    while (true) {
#ifdef CYGSEM_REDBOOT_FLASH_CONFIG
        if (script && *script) {
            c = *script++;
        } else
#endif
        if ((timeout > 0) && (ptr == buf)) {
            mon_set_read_char_timeout(50);
            while (timeout > 0) {
                res = mon_read_char_with_timeout(&c);
                if (res) {
                    // Got a character
                    break;
                }
                timeout -= 50;
            }
            if (res == false) {
                return _GETS_TIMEOUT;  // Input timed out
            }
        } else {
            mon_read_char(&c);
        }
        *ptr = '\0';
        switch (c) {
[...]        
========================================================================

The test ((timeout > 0) && (ptr == buf)) means that the timeout
only applies for the first character, and once we've received
that first character we use blocking reads until we see an
end-of-line?

That means that network polling stops and TCP sockets (and
associated timers) go dead between between the time the first
character is received and the newline is received?  [I don't
think that's a problem, but it's something to keep in mind.]


I'm also curious about the inner loop:

            mon_set_read_char_timeout(50);
            while (timeout > 0) {
                res = mon_read_char_with_timeout(&c);
                if (res) {
                    // Got a character
                    break;
                }
                timeout -= 50;
            }

Would the following be equivalent?

            mon_set_read_char_timeout(timeout);
            res = mon_read_char_with_timeout(&c);

-- 
Grant Edwards
grante@visi.com


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