timeval.c

/*
 * Copyright (c) Regents of The University of Michigan
 * See COPYING.
 */

#include <sys/time.h>

#include "timeval.h"

int
tv_add(struct timeval *tp1, struct timeval *tp2, struct timeval *result) {

    /* Add */
    result->tv_sec = tp1->tv_sec + tp2->tv_sec;
    result->tv_usec = tp1->tv_usec + tp2->tv_usec;

    /* Check and correct usec overflow */
    if (result->tv_usec >= 1000000) {
        result->tv_sec += 1;
        result->tv_usec -= 1000000;
    }
    return 0;
}

int
tv_sub(struct timeval *tp1, struct timeval *tp2, struct timeval *result) {
    result->tv_sec = tp1->tv_sec;
    result->tv_usec = tp1->tv_usec;

    /* Borrow */
    if (tp1->tv_usec < tp2->tv_usec) {
        result->tv_sec -= 1;
        result->tv_usec += 1000000;
    }

    /* Subtract */
    result->tv_sec = result->tv_sec - tp2->tv_sec;
    result->tv_usec = result->tv_usec - tp2->tv_usec;

    /* Check for negative result */
    if (result->tv_sec < 0) {
        result->tv_sec = 0;
        result->tv_usec = 0;
        return (-1);
    }

    return 0;
}

int
tv_lt(struct timeval *tp1, struct timeval *tp2) {
    if ((tp1->tv_sec < tp2->tv_sec) ||
            ((tp1->tv_sec == tp2->tv_sec) && (tp1->tv_usec < tp2->tv_usec))) {
        return 1;
    } else {
        return 0;
    }
}

int
tv_gt(struct timeval *tp1, struct timeval *tp2) {
    if ((tp1->tv_sec < tp2->tv_sec) ||
            ((tp1->tv_sec == tp2->tv_sec) && (tp1->tv_usec < tp2->tv_usec))) {
        return 0;
    } else {
        return 1;
    }
}