Implement to unmarshal PT duration

Author: miyukki

mpd/duration.go

@@ -4,6 +4,8 @@ package mpd
 
 import (
 	"encoding/xml"
+	"strconv"
+	"strings"
 	"time"
 )
 
@@ -13,6 +15,15 @@ func (d Duration) MarshalXMLAttr(name xml.Name) (xml.Attr, error) {
 	return xml.Attr{name, d.String()}, nil
 }
 
+func (d *Duration) UnmarshalXMLAttr(attr xml.Attr) error {
+	dur, err := parseDuration(attr.Value)
+	if err != nil {
+		return err
+	}
+	*d = Duration(dur)
+	return nil
+}
+
 // String renders a Duration in XML Duration Data Type format
 func (d *Duration) String() string {
 	// Largest time is 2540400h10m10.000000000s
@@ -126,3 +137,42 @@ func fmtInt(buf []byte, v uint64) int {
 	}
 	return w
 }
+
+func parseDuration(str string) (time.Duration, error) {
+	if strings.HasPrefix(str, "PT") {
+		offset := 2
+		var sum float64
+
+		if i := strings.Index(str[offset:], "H"); i != -1 {
+			hours, err := strconv.ParseInt(str[offset:offset+i], 10, 64)
+			if err != nil {
+				return 0, err
+			}
+			sum += float64(hours) * 60 * 60
+			offset += i + 1
+		}
+		if i := strings.Index(str[offset:], "M"); i != -1 {
+			minutes, err := strconv.ParseInt(str[offset:offset+i], 10, 64)
+			if err != nil {
+				return 0, err
+			}
+			sum += float64(minutes) * 60
+			offset += i + 1
+		}
+		if i := strings.Index(str[offset:], "S"); i != -1 {
+			seconds, err := strconv.ParseFloat(str[offset:offset+i], 64)
+			if err != nil {
+				return 0, err
+			}
+			sum += seconds
+		}
+
+		return time.Duration(sum * float64(time.Second)), nil
+	}
+
+	dur, err := strconv.ParseFloat(str, 64)
+	if err != nil {
+		return 0, err
+	}
+	return time.Duration(dur * float64(time.Second)), nil
+}

mpd/duration_test.go

@@ -20,3 +20,19 @@ func TestDuration(t *testing.T) {
 		assert.Equal(t, ex, dur.String())
 	}
 }
+
+func TestParseDuration(t *testing.T) {
+	in := map[string]float64{
+		"PT0S":         0,
+		"PT1M":         60,
+		"PT2H":         7200,
+		"PT6M16S":      376,
+		"PT1.97S":      1.97,
+		"PT1H2M3.456S": 3723.456,
+	}
+	for ins, ex := range in {
+		act, err := parseDuration(ins)
+		assert.NoError(t, err)
+		assert.Equal(t, ex, act.Seconds())
+	}
+}