Time string to time_t

[farmer]

Hello, i am trying to write an function that takes for an argument:
a string filled with numbers that mark the number of miliseconds elapsed since 1970 epoch.

The function should return a time_t value containing number of seconds elapsed since epoch.

My current implementation looks like this:

time_t util_extract_seconds_from_jstime_string(const char *jstime)
{
	time_t retval;
	char *seconds = (char *)malloc((strlen(jstime) - 2)*sizeof(char));
	strncpy(seconds,jstime,strlen(jstime) - 3);
	seconds[strlen(seconds)] = '\0';
	retval = (time_t) _strtoi64(seconds, NULL, 10);
	seconds = NULL;
	free(seconds);
	return retval;
}

However this implementation is rather sloppy cause of the additional malloc used and cause of the _strtoi64 function call. I would like to have a portable function.

Any suggestions?

[MK27]

Use strtol(). I don't know why you are trimming the end of the submitted string, but you could put it into a local variable.

[farmer]

Use strtol(). I don't know why you are trimming the end of the submitted string, but you could put it into a local variable.

Okay. I will use strtol. I am trimming at the end cause the last three characters are miliseconds, i need only seconds. I thought trimming the string is more elegant than div with 1000?

[quzah]

strptime + mktime?


Quzah.

[farmer]

strptime + mktime?


Quzah.

strptime does not exist in windows

[Salem]

Unless you're expecting time strings far into the future, millisecond time since 1970 is always going to be 12 characters for a good while.

So perhaps have a local array, and remove your memory leak and buffer overrun errors.

char buff[20];
size_t jsLen = strlen(jstime);
if ( jsLen < 20 && jsLen > 3 ) {
  strcpy( buff, jstime );
  buff[jsLen-3] = '\0';
  time_t result = strtoul(buff);
  // check for errors
} else {
  // panic, or something
}

[farmer]

Unless you're expecting time strings far into the future, millisecond time since 1970 is always going to be 12 characters for a good while.

Yes, thank you for this solution. Works like a charm.