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mtr 0.94

    1: /*
    2:     mtr  --  a network diagnostic tool
    3:     Copyright (C) 2016  Matt Kimball
    4: 
    5:     This program is free software; you can redistribute it and/or modify
    6:     it under the terms of the GNU General Public License version 2 as
    7:     published by the Free Software Foundation.
    8: 
    9:     This program is distributed in the hope that it will be useful,
   10:     but WITHOUT ANY WARRANTY; without even the implied warranty of
   11:     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   12:     GNU General Public License for more details.
   13: 
   14:     You should have received a copy of the GNU General Public License along
   15:     with this program; if not, write to the Free Software Foundation, Inc.,
   16:     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
   17: */
   18: 
   19: #include "timeval.h"
   20: 
   21: /*
   22:     Ensure that a timevalue has a microsecond value in the range
   23:     [0.0, 1.0e6) microseconds by converting microseconds to full seconds.
   24: */
   25: void normalize_timeval(
   26:     struct timeval *timeval)
   27: {
   28:     int full_sec;
   29: 
   30:     /*
   31:        If tv_usec has overflowed a full second, convert the overflow
   32:        to tv_sec.
   33:      */
   34:     full_sec = timeval->tv_usec / 1000000;
   35:     timeval->tv_sec += full_sec;
   36:     timeval->tv_usec -= 1000000 * full_sec;
   37: 
   38:     /*  If tv_usec is negative, make it positive by rolling tv_sec back  */
   39:     if (timeval->tv_usec < 0) {
   40:         timeval->tv_sec--;
   41:         timeval->tv_usec += 1000000;
   42:     }
   43: 
   44:     /*  If the entire time value is negative, clamp to zero  */
   45:     if (timeval->tv_sec < 0) {
   46:         timeval->tv_sec = 0;
   47:         timeval->tv_usec = 0;
   48:     }
   49: }
   50: 
   51: /*
   52:     Compare two time values.  Return:
   53: 
   54:         -1 if a < b
   55:          0 if a == b
   56:          1 if a > b
   57: */
   58: int compare_timeval(
   59:     struct timeval a,
   60:     struct timeval b)
   61: {
   62:     if (a.tv_sec > b.tv_sec) {
   63:         return 1;
   64:     }
   65:     if (a.tv_sec < b.tv_sec) {
   66:         return -1;
   67:     }
   68: 
   69:     if (a.tv_usec > b.tv_usec) {
   70:         return 1;
   71:     }
   72:     if (a.tv_usec < b.tv_usec) {
   73:         return -1;
   74:     }
   75: 
   76:     return 0;
   77: }