/*
 * hrtime.cpp
 *
 *  Created on: Oct 4, 2009
 *      Author: Michael Fischer
 *  For use in Yale course CPSC 427a, Fall 2010
 */

#include "tools.hpp"
#include "hrtime.hpp"

//-------------------------------------------------------------------
// Read system clock
void HirezTime::readClock() {
    int ret = gettimeofday(this, NULL);
    if (ret<0) perror("Error reading clock");
}

//-------------------------------------------------------------------
// Operator extension to add two HirezTime values
HirezTime
HirezTime::operator+(HirezTime ht2) const {
    long sum_sec = tv_sec + ht2.tv_sec;
    long sum_usec = tv_usec + ht2.tv_usec;
    if (sum_usec >= 1000000L) {
        sum_usec -= 1000000L;
        sum_sec++;
    }
    return HirezTime(sum_sec, sum_usec);
}

//-------------------------------------------------------------------
// Operator extension to subtract two HirezTime values
// Assumes first operand >= second, so difference is non-negative.
HirezTime
HirezTime::operator-(HirezTime ht2) const {
    long diff_sec = tv_sec - ht2.tv_sec;
    long diff_usec = tv_usec - ht2.tv_usec;
    if (diff_sec < 0 || (diff_sec == 0 && diff_usec < 0))
        fatal("Can't handle negative time differences");
    if (diff_usec < 0) {
        diff_usec += 1000000L;
        diff_sec--;
    }
    return HirezTime(diff_sec, diff_usec);
}

//-------------------------------------------------------------------
// Prints HirezTime value in seconds as a decimal fraction.
ostream&
HirezTime::print(ostream& os) const {
    char prev = cout.fill('0');
    os<< tv_sec<< "."<< right<< setw(6)<< tv_usec;
    cout.fill(prev);
    return os;
}