Corrected negative timers

repl/lib_timer.c

@@ -5,21 +5,43 @@
 
 #include <stdio.h>
 
+//GOD DAMN IT: https://stackoverflow.com/questions/15846762/timeval-subtract-explanation
+int timeval_subtract(struct timeval *result, struct timeval *x, struct timeval *y) {
+	//normallize
+	if (x->tv_usec > 999999) {
+		x->tv_sec += x->tv_usec / 1000000;
+		x->tv_usec %= 1000000;
+	}
+
+	if (y->tv_usec > 999999) {
+		y->tv_sec += y->tv_usec / 1000000;
+		y->tv_usec %= 1000000;
+	}
+
+	//calc
+	result->tv_sec = x->tv_sec - y->tv_sec;
+
+	if ((result->tv_usec = x->tv_usec - y->tv_usec) < 0) {
+		if (result->tv_sec != 0) { //only works far from 0
+			result->tv_usec += 1000000;
+			result->tv_sec--; // borrow
+		}
+	}
+
+	return result->tv_sec < 0 || (result->tv_sec == 0 && result->tv_usec < 0);
+}
+
 //god damn it
 static struct timeval* diff(struct timeval* lhs, struct timeval* rhs) {
 	struct timeval* d = ALLOCATE(struct timeval, 1);
 
-	d->tv_sec = rhs->tv_sec - lhs->tv_sec;
+	//I gave up, copied from SO
-	d->tv_usec = rhs->tv_usec - lhs->tv_usec;
+	timeval_subtract(d, rhs, lhs);
-
-	if (d->tv_usec < 0) {
-		d->tv_sec--;
-		d->tv_usec += 1000 * 1000;
-	}
 
 	return d;
 }
 
+//callbacks
 static int nativeStartTimer(Interpreter* interpreter, LiteralArray* arguments) {
 	//no arguments
 	if (arguments->count != 0) {
@@ -107,6 +129,13 @@ static int nativeCreateTimer(Interpreter* interpreter, LiteralArray* arguments)
 		return -1;
 	}
 
+	if (AS_INTEGER(microsecondLiteral) <= -1000 * 1000 || AS_INTEGER(microsecondLiteral) >= 1000 * 1000) {
+		interpreter->errorOutput("Microseconds out of range in createTimer\n");
+		freeLiteral(secondLiteral);
+		freeLiteral(microsecondLiteral);
+		return -1;
+	}
+
 	//get the timeinfo from toy
 	struct timeval* timeinfo = ALLOCATE(struct timeval, 1);
 	timeinfo->tv_sec = AS_INTEGER(secondLiteral);
@@ -259,9 +288,17 @@ static int nativeTimerToString(Interpreter* interpreter, LiteralArray* arguments
 	struct timeval* timer = AS_OPAQUE(timeLiteral);
 
 	//create the string literal
+	Literal resultLiteral = TO_NULL_LITERAL;
+	if (timer->tv_sec == 0 && timer->tv_usec < 0) { //special case, for when the negative sign is encoded in the usec
+		char buffer[128];
+		snprintf(buffer, 128, "-%ld.%06ld", timer->tv_sec, -timer->tv_usec);
+		resultLiteral = TO_STRING_LITERAL( copyString(buffer, strlen(buffer)), strlen(buffer));
+	}
+	else { //normal case
 		char buffer[128];
 		snprintf(buffer, 128, "%ld.%06ld", timer->tv_sec, timer->tv_usec);
-	Literal resultLiteral = TO_STRING_LITERAL( copyString(buffer, strlen(buffer)), strlen(buffer));
+		resultLiteral = TO_STRING_LITERAL( copyString(buffer, strlen(buffer)), strlen(buffer));
+	}
 
 	pushLiteralArray(&interpreter->stack, resultLiteral);
 

scripts/small.toy

@@ -0,0 +1,13 @@
+import timer;
+
+var a = createTimer(1, 0);
+var b = createTimer(2, 0);
+
+print a.compareTimer(b).timerToString();
+print b.compareTimer(a).timerToString();
+
+var c = createTimer(0, 1);
+var d = createTimer(0, 2);
+
+print c.compareTimer(d).timerToString();
+print d.compareTimer(c).timerToString();

test/scripts/lib/timer.toy

@@ -56,5 +56,37 @@
 	timer.destroyTimer();
 }
 
+{
+	//test positive and negative values of timers
+	import timer;
+
+	var a = createTimer(1, 0);
+	var b = createTimer(2, 0);
+
+	var acmp = a.compareTimer(b);
+	var bcmp = b.compareTimer(a);
+
+	var c = createTimer(0, 1);
+	var d = createTimer(0, 2);
+
+	var ccmp = c.compareTimer(d);
+	var dcmp = d.compareTimer(c);
+
+	assert acmp.timerToString() == "1.000000", "positive and negative tests failed (acmp)";
+	assert bcmp.timerToString() == "-1.000000", "positive and negative tests failed (bcmp)";
+	assert ccmp.timerToString() == "0.000001", "positive and negative tests failed (ccmp)";
+	assert dcmp.timerToString() == "-0.000001", "positive and negative tests failed (dcmp)";
+
+	a.destroyTimer();
+	b.destroyTimer();
+	c.destroyTimer();
+	d.destroyTimer();
+	acmp.destroyTimer();
+	bcmp.destroyTimer();
+	ccmp.destroyTimer();
+	dcmp.destroyTimer();
+}
+
 
 print "All good";
+