/**
* @license
* Copyright 2016 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.TimeRangesUtils');
/**
* @namespace shaka.media.TimeRangesUtils
* @summary A set of utility functions for dealing with TimeRanges objects.
*/
/**
* Gets the first timestamp in buffer.
*
* @param {TimeRanges} b
* @return {?number} The first buffered timestamp, in seconds, if |buffered|
* is non-empty; otherwise, return null.
*/
shaka.media.TimeRangesUtils.bufferStart = function(b) {
if (!b) return null;
// Workaround Safari bug: https://goo.gl/EDRCoZ
if (b.length == 1 && b.end(0) - b.start(0) < 1e-6) return null;
// Workaround Edge bug: https://goo.gl/BtxKgb
if (b.length == 1 && b.start(0) < 0) return 0;
return b.length ? b.start(0) : null;
};
/**
* Gets the last timestamp in buffer.
*
* @param {TimeRanges} b
* @return {?number} The last buffered timestamp, in seconds, if |buffered|
* is non-empty; otherwise, return null.
*/
shaka.media.TimeRangesUtils.bufferEnd = function(b) {
if (!b) return null;
// Workaround Safari bug: https://goo.gl/EDRCoZ
if (b.length == 1 && b.end(0) - b.start(0) < 1e-6) return null;
return b.length ? b.end(b.length - 1) : null;
};
/**
* Determines if the given time is inside a buffered range. This includes gaps,
* meaning if the playhead is in a gap, it is considered buffered.
*
* @param {TimeRanges} b
* @param {number} time
* @return {boolean}
*/
shaka.media.TimeRangesUtils.isBuffered = function(b, time) {
if (!b || !b.length) return false;
// Workaround Safari bug: https://goo.gl/EDRCoZ
if (b.length == 1 && b.end(0) - b.start(0) < 1e-6) return false;
return time >= b.start(0) && time <= b.end(b.length - 1);
};
/**
* Computes how far ahead of the given timestamp is buffered. To provide smooth
* playback while jumping gaps, we don't include the gaps when calculating this.
* This only includes the amount of content that is buffered.
*
* @param {TimeRanges} b
* @param {number} time
* @return {number} The number of seconds buffered, in seconds, ahead of the
* given time.
*/
shaka.media.TimeRangesUtils.bufferedAheadOf = function(b, time) {
if (!b || !b.length) return 0;
// Workaround Safari bug: https://goo.gl/EDRCoZ
if (b.length == 1 && b.end(0) - b.start(0) < 1e-6) return 0;
// NOTE: On IE11, buffered ranges may show appended data before the associated
// append operation is complete.
// We calculate buffered amount by ONLY accounting for the content buffered
// (i.e. we ignore the times of the gaps). We also buffer through all gaps.
// So start at the end and add up all buffers until |time|.
var result = 0;
for (var i = b.length - 1; i >= 0 && b.end(i) > time; --i) {
result += b.end(i) - Math.max(b.start(i), time);
}
return result;
};
/**
* Determines if the given time is inside a gap between buffered ranges. If it
* is, this returns the index of the buffer that is *ahead* of the gap.
*
* @param {TimeRanges} b
* @param {number} time
* @return {?number} The index of the buffer after the gap, or null if not in a
* gap.
*/
shaka.media.TimeRangesUtils.getGapIndex = function(b, time) {
if (!b || !b.length) return null;
// Workaround Safari bug: https://goo.gl/EDRCoZ
if (b.length == 1 && b.end(0) - b.start(0) < 1e-6) return null;
// IE/Edge stops 0.5 seconds before a gap, so it needs a much larger
// threshold, but we don't want to punish other browsers that stop closer.
// See: https://goo.gl/cuAcYd
var threshold = 0.1;
if (/(Edge\/|Trident\/|Tizen)/.test(navigator.userAgent))
threshold = 0.5;
for (var i = 0; i < b.length; i++) {
if (b.start(i) > time && (i == 0 || b.end(i - 1) - time <= threshold)) {
return i;
}
}
return null;
};