Rename mono to rtptime.

rtptime/rtptime.go

@@ -0,0 +1,41 @@
+package rtptime
+
+import (
+	"time"
+)
+
+var epoch = time.Now()
+
+func FromDuration(d time.Duration, hz uint32) uint64 {
+	return uint64(d) * uint64(hz) / uint64(time.Second)
+}
+
+func toDuration(tm uint64, hz uint32) time.Duration {
+	return time.Duration(tm * uint64(time.Second) / uint64(hz))
+}
+
+func Now(hz uint32) uint64 {
+	return FromDuration(time.Since(epoch), hz)
+}
+
+func Microseconds() uint64 {
+	return Now(1000000)
+}
+
+var ntpEpoch = time.Date(1900, 1, 1, 0, 0, 0, 0, time.UTC)
+
+func NTPToTime(ntp uint64) time.Time {
+	sec := uint32(ntp >> 32)
+	frac := uint32(ntp & 0xFFFFFFFF)
+	return ntpEpoch.Add(
+		time.Duration(sec) * time.Second +
+			((time.Duration(frac) * time.Second) >> 32),
+	)
+}
+
+func TimeToNTP(tm time.Time) uint64 {
+	d := tm.Sub(ntpEpoch)
+	sec := uint32(d / time.Second)
+	frac := uint32(d % time.Second)
+	return (uint64(sec) << 32) + (uint64(frac) << 32) / uint64(time.Second)
+}

rtptime/rtptime_test.go

@@ -0,0 +1,67 @@
+package rtptime
+
+import (
+	"testing"
+	"time"
+)
+
+func TestDuration(t *testing.T) {
+	a := FromDuration(time.Second, 48000)
+	if a != 48000 {
+		t.Errorf("Expected 48000, got %v", a)
+	}
+
+	b := toDuration(48000, 48000)
+	if b != time.Second {
+		t.Errorf("Expected %v, got %v", time.Second, b)
+	}
+}
+
+func differs(a, b, delta uint64) bool {
+	if a < b {
+		a, b = b, a
+	}
+	return a - b >= delta
+}
+
+func TestMono(t *testing.T) {
+	a := Now(48000)
+	time.Sleep(4 * time.Millisecond)
+	b := Now(48000) - a
+	if differs(b, 4 * 48, 16) {
+		t.Errorf("Expected %v, got %v", 4 * 48, b)
+	}
+
+	c := Microseconds()
+	time.Sleep(4 * time.Millisecond)
+	d := Microseconds() - c
+	if differs(d, 4000, 1000) {
+		t.Errorf("Expected %v, got %v", 4000, d)
+	}
+}
+
+func TestNTP(t *testing.T) {
+	now := time.Now()
+	ntp := TimeToNTP(now)
+	now2 := NTPToTime(ntp)
+	ntp2 := TimeToNTP(now2)
+
+	diff1 := now2.Sub(now)
+	if diff1 < 0 {
+		diff1 = -diff1
+	}
+	if diff1 > time.Nanosecond {
+		t.Errorf("Expected %v, got %v (diff=%v)",
+			now, now2, diff1)
+	}
+
+	diff2 := int64(ntp2 - ntp)
+	if diff2 < 0 {
+		diff2 = -diff2
+	}
+	if diff2 > (1 << 8) {
+		t.Errorf("Expected %v, got %v (diff=%v)",
+			ntp, ntp2, float64(diff2) / float64(1<<32))
+	}
+
+}