Function FastTimeToBuffer

be/src/gutil/strings/util.cc:590–665

}

char* FastTimeToBuffer(time_t s, char* buffer) {
  if (s == 0) {
    time(&s);
  }

  struct tm tm;
  if (PortableSafeGmtime(&s, &tm) == nullptr) {
    // Error message must fit in 30-char buffer.
    memcpy(buffer, "Invalid:", sizeof("Invalid:"));
    FastInt64ToBufferLeft(s, buffer+strlen(buffer));
    return buffer;
  }

  // strftime format: "%a, %d %b %Y %H:%M:%S GMT",
  // but strftime does locale stuff which we do not want
  // plus strftime takes > 10x the time of hard code

  const char* weekday_name = "Xxx";
  switch (tm.tm_wday) {
    default: { DLOG(FATAL) << "tm.tm_wday: " << tm.tm_wday; } break;
    case 0:  weekday_name = "Sun"; break;
    case 1:  weekday_name = "Mon"; break;
    case 2:  weekday_name = "Tue"; break;
    case 3:  weekday_name = "Wed"; break;
    case 4:  weekday_name = "Thu"; break;
    case 5:  weekday_name = "Fri"; break;
    case 6:  weekday_name = "Sat"; break;
  }

  const char* month_name = "Xxx";
  switch (tm.tm_mon) {
    default:  { DLOG(FATAL) << "tm.tm_mon: " << tm.tm_mon; } break;
    case 0:   month_name = "Jan"; break;
    case 1:   month_name = "Feb"; break;
    case 2:   month_name = "Mar"; break;
    case 3:   month_name = "Apr"; break;
    case 4:   month_name = "May"; break;
    case 5:   month_name = "Jun"; break;
    case 6:   month_name = "Jul"; break;
    case 7:   month_name = "Aug"; break;
    case 8:   month_name = "Sep"; break;
    case 9:   month_name = "Oct"; break;
    case 10:  month_name = "Nov"; break;
    case 11:  month_name = "Dec"; break;
  }

  // Write out the buffer.

  memcpy(buffer+0, weekday_name, 3);
  buffer[3] = ',';
  buffer[4] = ' ';

  PutTwoDigits(tm.tm_mday, buffer+5);
  buffer[7] = ' ';

  memcpy(buffer+8, month_name, 3);
  buffer[11] = ' ';