/**
* @license
* Copyright 2015 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
goog.provide('shaka.media.SegmentReference');
goog.require('shaka.asserts');
goog.require('shaka.util.FailoverUri');
/**
* Creates a SegmentReference, which is a reference to some media segment.
*
* @param {number} startTime The time, in seconds, that the segment begins.
* @param {?number} endTime The time, in seconds, that the segment ends. The
* segment ends immediately before this time. A null value indicates that
* the segment continues to the end of the stream.
* @param {!shaka.util.FailoverUri} url The failover url of the media segment.
* @constructor
* @struct
*/
shaka.media.SegmentReference = function(startTime, endTime, url) {
shaka.asserts.assert((endTime == null) || (startTime <= endTime),
'startTime should be <= endTime');
/**
* The time, in seconds, that the segment begins.
* @const {number}
*/
this.startTime = startTime;
/**
* The time, in seconds, that the segment ends. The segment ends immediately
* before this time. A null value indicates that the segment continues to the
* end of the stream.
* @const {?number}
*/
this.endTime = endTime;
/**
* The segment's location.
* @const {!shaka.util.FailoverUri}
*/
this.url = url;
};
/**
* Creates a new SegmentReference with an adjusted start time and an adjusted
* end time.
*
* @param {number} startTime
* @param {?number} endTime
* @return {!shaka.media.SegmentReference}
*/
shaka.media.SegmentReference.prototype.adjust = function(startTime, endTime) {
return new shaka.media.SegmentReference(
startTime,
endTime,
this.url);
};
/**
* Gets the index into |references| of the SegmentReference corresponding to
* the specified time.
*
* @param {!Array.<!shaka.media.SegmentReference>} references
* @param {number} time The time in seconds.
* @return {number} The index of the SegmentReference for the specified time,
* or -1 if no such SegmentReference exists.
*/
shaka.media.SegmentReference.find = function(references, time) {
// For live streams, searching from the end is faster. For VOD, it balances
// out either way. In both cases, references.length is small enough that the
// difference isn't huge.
for (var i = references.length - 1; i >= 0; --i) {
var r = references[i];
// Note that a segment ends immediately before the end time.
if ((time >= r.startTime) && (r.endTime == null || time < r.endTime)) {
return i;
}
}
return -1;
};
/**
* Shifts each SegmentReference in time by |delta| seconds.
*
* @param {!Array.<!shaka.media.SegmentReference>} references
* @param {number} delta
* @return {!Array.<!shaka.media.SegmentReference>} The shifted
* SegmentReferences.
*/
shaka.media.SegmentReference.shift = function(references, delta) {
return references.map(
function(r) {
return r.adjust(r.startTime + delta,
r.endTime != null ? r.endTime + delta : null);
});
};
/**
* Asserts that |references| are sorted by their start times without gaps and
* have unique start times.
*
* For debugging purposes.
*
* @param {!Array.<!shaka.media.SegmentReference>} references
*/
shaka.media.SegmentReference.assertCorrectReferences = function(references) {
if (!COMPILED) {
var previous = references[0];
for (var i = 1; i < references.length; ++i) {
var r = references[i];
var ok = (r.startTime > previous.startTime) &&
(r.startTime <= previous.endTime) &&
((r.endTime && r.endTime >= previous.endTime) ||
(i == references.length - 1));
shaka.asserts.assert(ok, 'SegmentReferences are not correct.');
if (!ok) {
shaka.log.debug(
'SegmentReferences should be sorted without gaps:',
'previous', previous, 'current', r);
}
previous = r;
}
}
};