mdw@git.distorted.org.uk Git - mLib/blob - tv.c

   1 /* -*-c-*-
   2  *
   3  * $Id: tv.c,v 1.2 1999/05/05 18:50:31 mdw Exp $
   4  *
   5  * Manipulation of timeval structures
   6  *
   7  * (c) 1998 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the mLib utilities library.
  13  *
  14  * mLib is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * mLib is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with mLib; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: tv.c,v $
  32  * Revision 1.2  1999/05/05 18:50:31  mdw
  33  * Change licensing conditions to LGPL.
  34  *
  35  * Revision 1.1  1998/11/25 23:30:01  mdw
  36  * New file.
  37  *
  38  */
  39
  40 /*----- Header files ------------------------------------------------------*/
  41
  42 #include <sys/time.h>
  43 #include "tv.h"
  44
  45 /*----- Main code ---------------------------------------------------------*/
  46
  47 /* --- @tv_add@ --- *
  48  *
  49  * Arguments:   @struct timeval *dst@ = destination block
  50  *              @const struct timeval *a, *b@ = source blocks
  51  *
  52  * Returns:     ---
  53  *
  54  * Use:         Adds two timevals.
  55  */
  56
  57 void tv_add(struct timeval *dst,
  58             const struct timeval *a, const struct timeval *b)
  59 {
  60   dst->tv_sec = a->tv_sec + b->tv_sec;
  61   dst->tv_usec = a->tv_usec + b->tv_usec;
  62   if (dst->tv_usec >= 1000000) {
  63     dst->tv_usec -= 1000000;
  64     dst->tv_sec++;
  65   }
  66 }
  67
  68 /* --- @tv_sub@ --- *
  69  *
  70  * Arguments:   @struct timeval *dst@ = destination block
  71  *              @const struct timeval *a, *b@ = source blocks
  72  *
  73  * Returns:     ---
  74  *
  75  * Use:         Subtracts two timevals.
  76  */
  77
  78 void tv_sub(struct timeval *dst,
  79             const struct timeval *a, const struct timeval *b)
  80 {
  81   dst->tv_sec = a->tv_sec - b->tv_sec;
  82   if (a->tv_usec >= b->tv_usec)
  83     dst->tv_usec = a->tv_usec - b->tv_usec;
  84   else {
  85     dst->tv_usec = a->tv_usec + 1000000 - b->tv_usec;
  86     dst->tv_sec--;
  87   }
  88 }
  89
  90 /* --- @tv_cmp@ --- *
  91  *
  92  * Arguments:   @const struct timeval *a, *b@ = source blocks
  93  *
  94  * Returns:     Less than, equal to, or greater than zero.
  95  *
  96  * Use:         Compares two timevals.
  97  */
  98
  99 int tv_cmp(const struct timeval *a, const struct timeval *b)
 100 {
 101   if (a->tv_sec > b->tv_sec)
 102     return (1);
 103   else if (a->tv_sec < b->tv_sec)
 104     return (-1);
 105   else if (a->tv_usec > b->tv_usec)
 106     return (1);
 107   else if (a->tv_usec < b->tv_usec)
 108     return (-1);
 109   else
 110     return (0);
 111 }
 112
 113 /*----- That's all, folks -------------------------------------------------*/