Stopwatch.c

#include <malloc.h>
#include "Stopwatch.h"

double seconds() {
	return ((double) clock()) / (double) CLOCKS_PER_SEC;
}

void Stopwtach_reset(Stopwatch Q) {
	Q->running = 0;         /* false */
	Q->last_time = 0.0;
	Q->total= 0.0;
}


Stopwatch new_Stopwatch(void) {
	Stopwatch S = (Stopwatch) malloc(sizeof(Stopwatch_struct));
	if (S == NULL)
		return NULL;

	Stopwtach_reset(S);
	return S;
}

void Stopwatch_delete(Stopwatch S) {
	if (S != NULL)
		free(S);
}


/* Start resets the timer to 0.0; use resume for continued total */

void Stopwatch_start(Stopwatch Q) {
	if (! (Q->running)  ) {
		Q->running = 1;  /* true */
		Q->total = 0.0;
		Q->last_time = seconds();
	}
}

/**
    Resume timing, after stopping.  (Does not wipe out
        accumulated times.)

*/

void Stopwatch_resume(Stopwatch Q) {
	if (!(Q->running)) {
		Q-> last_time = seconds();
		Q->running = 1;  /*true*/
	}
}

void Stopwatch_stop(Stopwatch Q) {
	if (Q->running) {
		Q->total += seconds() - Q->last_time;
		Q->running = 0;  /* false */
	}
}


double Stopwatch_read(Stopwatch Q) {

	if (Q->running) {
		double t = seconds();
		Q->total += t - Q->last_time;
		Q->last_time = t;
	}
	return Q->total;
}