feat: add support for endNumber in template duration parsing (#120)

src/segment/durationTimeParser.js

@@ -1,5 +1,27 @@
 import { range } from '../utils/list';
 
+/**
+ * parse the end number attribue that can be a string
+ * number, or undefined.
+ *
+ * @param {string|number|undefined} endNumber
+ *        The end number attribute.
+ *
+ * @return {number|null}
+ *          The result of parsing the end number.
+ */
+const parseEndNumber = (endNumber) => {
+  if (endNumber && typeof endNumber !== 'number') {
+    endNumber = parseInt(endNumber, 10);
+  }
+
+  if (isNaN(endNumber)) {
+    return null;
+  }
+
+  return endNumber;
+};
+
 /**
  * Functions for calculating the range of available segments in static and dynamic
  * manifests.
@@ -19,10 +41,11 @@ export const segmentRange = {
       timescale = 1,
       sourceDuration
     } = attributes;
+    const endNumber = parseEndNumber(attributes.endNumber);
 
     return {
       start: 0,
-      end: Math.ceil(sourceDuration / (duration / timescale))
+      end: typeof endNumber === 'number' ? endNumber : Math.ceil(sourceDuration / (duration / timescale))
     };
   },
 
@@ -45,6 +68,7 @@ export const segmentRange = {
       minimumUpdatePeriod = 0,
       timeShiftBufferDepth = Infinity
     } = attributes;
+    const endNumber = parseEndNumber(attributes.endNumber);
     const now = (NOW + clientOffset) / 1000;
     const periodStartWC = availabilityStartTime + start;
     const periodEndWC = now + minimumUpdatePeriod;
@@ -56,7 +80,7 @@ export const segmentRange = {
 
     return {
       start: Math.max(0, availableStart),
-      end: Math.min(segmentCount, availableEnd)
+      end: typeof endNumber === 'number' ? endNumber : Math.min(segmentCount, availableEnd)
     };
   }
 };

test/segment/segmentTemplate.test.js

@@ -235,6 +235,34 @@ QUnit.test('parseByDuration defaults 1 for startNumber and timescale', function(
   );
 });
 
+QUnit.test('parseByDuration uses endNumber and has correct duration', function(assert) {
+  const attributes = {
+    sourceDuration: 11,
+    duration: '4',
+    periodIndex: 1,
+    endNumber: '2'
+  };
+
+  assert.deepEqual(
+    parseTemplateInfo(attributes, []),
+    [
+      {
+        number: 1,
+        duration: 4,
+        timeline: 1,
+        time: 0
+      },
+      {
+        number: 2,
+        duration: 7,
+        timeline: 1,
+        time: 4
+      }
+    ],
+    'uses default startNumber and timescale value of 1'
+  );
+});
+
 QUnit.test('uses SegmentTimeline info when no @duration attribute', function(assert) {
   const attributes = {
     startNumber: 0,
@@ -987,6 +1015,55 @@ QUnit.test('correctly handles duration', function(assert) {
     }],
     'segments correct with given clientOffset'
   );
+
+  assert.deepEqual(
+    segmentsFromTemplate(Object.assign(
+      {}, basicAttributes,
+      { endNumber: '4' }, []
+    )),
+    [{
+      duration: 2,
+      map: {
+        resolvedUri: 'http://www.example.com/',
+        uri: ''
+      },
+      number: 1,
+      resolvedUri: 'http://www.example.com/n-1.m4s',
+      timeline: 1,
+      uri: 'n-1.m4s'
+    }, {
+      duration: 2,
+      map: {
+        resolvedUri: 'http://www.example.com/',
+        uri: ''
+      },
+      number: 2,
+      resolvedUri: 'http://www.example.com/n-2.m4s',
+      timeline: 1,
+      uri: 'n-2.m4s'
+    }, {
+      duration: 2,
+      map: {
+        resolvedUri: 'http://www.example.com/',
+        uri: ''
+      },
+      number: 3,
+      resolvedUri: 'http://www.example.com/n-3.m4s',
+      timeline: 1,
+      uri: 'n-3.m4s'
+    }, {
+      duration: 2,
+      map: {
+        resolvedUri: 'http://www.example.com/',
+        uri: ''
+      },
+      number: 4,
+      resolvedUri: 'http://www.example.com/n-4.m4s',
+      timeline: 1,
+      uri: 'n-4.m4s'
+    }],
+    'segments correct with endNumber'
+  );
 });
 
 QUnit.test('correctly handles duration with segmentTimeline', function(assert) {