psi: wrote func for update timstamp - as well as test (passes). Also wrote func for get timestamp - as well as test (passes)

stream/mts/psi/psi.go

@@ -77,7 +77,9 @@ const (
 )
 
 const (
-	timestampDescTag = 234
+	timeDescTag = 234
+	descTagIndx = 13
+	timeIndx    = 15
 )
 
 // Program specific information
@@ -358,11 +360,33 @@ func TimeToBytes(time uint64) []byte {
 	return s
 }
 
-// UpdateTimestamp
-func UpdateTimestamp(data []byte, t int) error {
-	psi := ReadPSI(data)
-	if psi.Tid != PATTableID {
-		return errors.New("Timestamp update failed because psi is not a PMT")
+func chkTime(d []byte) error {
+	if d[descTagIndx] != timeDescTag {
+		return errors.New("PSI does not contain a time descriptor, cannot update")
 	}
 	return nil
 }
+
+// Updatetime
+func UpdateTime(d []byte, t int) error {
+	err := chkTime(d)
+	if err != nil {
+		return err
+	}
+	ts := TimeToBytes(uint64(t))
+	for i := range d[timeIndx : timeIndx+8] {
+		d[i+timeIndx] = ts[i]
+	}
+	return nil
+}
+
+func GetTime(d []byte) (t uint64, err error) {
+	err = chkTime(d)
+	if err != nil {
+		return 0, err
+	}
+	for i := range d[timeIndx : timeIndx+8] {
+		t |= uint64(d[i+timeIndx]) << uint(56-i*8)
+	}
+	return t, nil
+}

stream/mts/psi/psi_test.go

@@ -6,7 +6,12 @@ import (
 )
 
 const (
-	testTime = 1235367435 // hex = 49A2360B
+	tstTime  = 1235367435 // hex = 49A2360B
+	tstTime2 = 1735357535 // hex = 676F745F
+)
+
+const (
+	errCmp = "Incorrect output, for: %v wanted: %v, got: %v"
 )
 
 var (
@@ -54,7 +59,7 @@ var (
 		},
 	}
 	// pmt with descriptor in it
-	StdPmtTimestamp = []byte{
+	StdPmtTime = []byte{
 		0x00, // pointer
 
 		// ---- section included in data sent to CRC32 during check
@@ -72,7 +77,7 @@ var (
 		0xe1, 0x00, // reserved:3|PCR PID:13
 		0xf0, 0x0a, // reserved:4|unused:2|program info length:10
 		// Desriptor
-		byte(timestampDescTag),                         // Descriptor tag
+		byte(timeDescTag),                              // Descriptor tag
 		byte(8),                                        // Length of bytes to follow
 		0x00, 0x00, 0x00, 0x00, 0x49, 0xA2, 0x36, 0x0B, // timestamp
 		// No program descriptors since program info length is 0.
@@ -85,7 +90,7 @@ var (
 		// 0x15, 0xbd, 0x4d, 0x56, // CRC
 		// ----
 	}
-	pmtPsiTimestamped = PSI{
+	pmtPsiTime = PSI{
 		Pf:  0x00,
 		Tid: 0x02,
 		Ssi: true,
@@ -101,9 +106,9 @@ var (
 				Pil:    10,
 				Pd: []Desc{
 					Desc{
-						Dt: byte(timestampDescTag),
+						Dt: byte(timeDescTag),
 						Dl: byte(8),
-						Dd: TimeToBytes(testTime),
+						Dd: TimeToBytes(tstTime),
 					},
 				},
 				Essd: &ESSD{
@@ -114,6 +119,38 @@ var (
 			},
 		},
 	}
+	// pmt with descriptor in it
+	StdPmtTime2 = []byte{
+		0x00, // pointer
+
+		// ---- section included in data sent to CRC32 during check
+		// table header
+		0x02, // table id
+		0xb0, // section syntax indicator:1|private bit:1|reserved:2|section length:2|more bytes...:2
+		0x12, // more bytes...
+
+		// syntax section
+		0x00, 0x01, // table id extension
+		0xc1, // reserved bits:3|version:5|use now:1
+		0x00, // section number
+		0x00, // last section number
+		// table data
+		0xe1, 0x00, // reserved:3|PCR PID:13
+		0xf0, 0x0a, // reserved:4|unused:2|program info length:10
+		// Desriptor
+		byte(timeDescTag),                              // Descriptor tag
+		byte(8),                                        // Length of bytes to follow
+		0x00, 0x00, 0x00, 0x00, 0x67, 0x6F, 0x74, 0x5F, // timestamp
+		// No program descriptors since program info length is 0.
+		// elementary stream info data
+		0x1b,       // stream type
+		0xe1, 0x00, // reserved:3|elementary PID:13
+		0xf0, 0x00, // reserved:4|unused:2|ES info length:10
+		// No elementary stream descriptors since ES info length is 0.
+
+		// 0x15, 0xbd, 0x4d, 0x56, // CRC
+		// ----
+	}
 )
 
 // Test Bytes for a standard pat
@@ -122,7 +159,7 @@ func TestBytesPAT1(t *testing.T) {
 	// Remove crc32
 	got = got[:len(got)-4]
 	if !bytes.Equal(StdPat, got) {
-		t.Errorf("Incorrect output, wanted: %v, got: %v", StdPat, got)
+		t.Errorf(errCmp, "TestBytesPAT1", StdPat, got)
 	}
 }
 
@@ -132,24 +169,46 @@ func TestBytesPMT1(t *testing.T) {
 	// Remove crc32
 	got = got[:len(got)-4]
 	if !bytes.Equal(StdPmt, got) {
-		t.Errorf("Incorrect output, wanted: %v, got: %v", StdPmt, got)
+		t.Errorf(errCmp, "TestBytesPMT1", StdPmt, got)
 	}
 }
 
 // A quick sanity check of the int64 time to []byte func
 func TestTimestampToBytes(t *testing.T) {
-	timeBytes := TimeToBytes(testTime)
+	timeBytes := TimeToBytes(tstTime)
 	if !bytes.Equal(timeSlice, timeBytes) {
-		t.Errorf("Incorrect results, wanted: %v, got: %v", timeSlice, timeBytes)
+		t.Errorf(errCmp, "testTimeStampToBytes", timeSlice, timeBytes)
 	}
 }
 
 // Test Bytes for a a standard PMT with a descripot containing a timestamp
 func TestBytesPmt2(t *testing.T) {
-	got := pmtPsiTimestamped.Bytes()
+	got := pmtPsiTime.Bytes()
 	// Remove crc32
 	got = got[:len(got)-4]
-	if !bytes.Equal(StdPmtTimestamp, got) {
-		t.Errorf("Incorrect output, wanted: %v, got: %v", StdPmtTimestamp, got)
+	if !bytes.Equal(StdPmtTime, got) {
+		t.Errorf(errCmp, "testBytesPmt2", StdPmtTime, got)
+	}
+}
+
+func TestTimeUpdate(t *testing.T) {
+	cpy := make([]byte, len(StdPmtTime))
+	copy(cpy, StdPmtTime)
+	err := UpdateTime(cpy, tstTime2)
+	if err != nil {
+		t.Errorf("Update time returned err: %v", err)
+	}
+	if !bytes.Equal(StdPmtTime2, cpy) {
+		t.Errorf(errCmp, "TestTimeUpdate", StdPmtTime2, cpy)
+	}
+}
+
+func TestTimeGet(t *testing.T) {
+	s, err := GetTime(StdPmtTime)
+	if err != nil {
+		t.Errorf("Getting timestamp failed with err: %v", err)
+	}
+	if s != tstTime {
+		t.Errorf(errCmp, "TestTimeGet", tstTime, s)
 	}
 }