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Annotation of embedaddon/mtr/packet/timeval.c, revision 1.1

1.1     ! misho       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
        !            15:     along with this program; if not, write to the Free Software
        !            16:     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, 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: }