third_party/WebKit/Source/core/html/TimeRanges.cpp

   1 /*
   2  * Copyright (C) 2007, 2009, 2010 Apple Inc.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "core/html/TimeRanges.h"
  28
  29 #include "bindings/core/v8/ExceptionMessages.h"
  30 #include "bindings/core/v8/ExceptionState.h"
  31 #include "bindings/core/v8/ExceptionStatePlaceholder.h"
  32 #include "core/dom/ExceptionCode.h"
  33 #include <math.h>
  34
  35 using namespace blink;
  36
  37 TimeRanges::TimeRanges(double start, double end)
  38 {
  39     add(start, end);
  40 }
  41
  42 TimeRanges* TimeRanges::create(const blink::WebTimeRanges& webRanges)
  43 {
  44     TimeRanges* ranges = TimeRanges::create();
  45
  46     unsigned size = webRanges.size();
  47     for (unsigned i = 0; i < size; ++i)
  48         ranges->add(webRanges[i].start, webRanges[i].end);
  49
  50     return ranges;
  51 }
  52
  53 TimeRanges* TimeRanges::copy() const
  54 {
  55     TimeRanges* newSession = TimeRanges::create();
  56
  57     unsigned size = m_ranges.size();
  58     for (unsigned i = 0; i < size; i++)
  59         newSession->add(m_ranges[i].m_start, m_ranges[i].m_end);
  60
  61     return newSession;
  62 }
  63
  64 void TimeRanges::invert()
  65 {
  66     TimeRanges* inverted = TimeRanges::create();
  67     double posInf = std::numeric_limits<double>::infinity();
  68     double negInf = -std::numeric_limits<double>::infinity();
  69
  70     if (!m_ranges.size()) {
  71         inverted->add(negInf, posInf);
  72     } else {
  73         double start = m_ranges.first().m_start;
  74         if (start != negInf)
  75             inverted->add(negInf, start);
  76
  77         for (size_t index = 0; index + 1 < m_ranges.size(); ++index)
  78             inverted->add(m_ranges[index].m_end, m_ranges[index + 1].m_start);
  79
  80         double end = m_ranges.last().m_end;
  81         if (end != posInf)
  82             inverted->add(end, posInf);
  83     }
  84
  85     m_ranges.swap(inverted->m_ranges);
  86 }
  87
  88 void TimeRanges::intersectWith(const TimeRanges* other)
  89 {
  90     ASSERT(other);
  91
  92     if (other == this)
  93         return;
  94
  95     TimeRanges* invertedOther = other->copy();
  96     invertedOther->invert();
  97
  98     invert();
  99     unionWith(invertedOther);
 100     invert();
 101 }
 102
 103 void TimeRanges::unionWith(const TimeRanges* other)
 104 {
 105     ASSERT(other);
 106     TimeRanges* unioned = copy();
 107     for (size_t index = 0; index < other->m_ranges.size(); ++index) {
 108         const Range& range = other->m_ranges[index];
 109         unioned->add(range.m_start, range.m_end);
 110     }
 111
 112     m_ranges.swap(unioned->m_ranges);
 113 }
 114
 115 double TimeRanges::start(unsigned index, ExceptionState& exceptionState) const
 116 {
 117     if (index >= length()) {
 118         exceptionState.throwDOMException(IndexSizeError, ExceptionMessages::indexExceedsMaximumBound("index", index, length()));
 119         return 0;
 120     }
 121     return m_ranges[index].m_start;
 122 }
 123
 124 double TimeRanges::end(unsigned index, ExceptionState& exceptionState) const
 125 {
 126     if (index >= length()) {
 127         exceptionState.throwDOMException(IndexSizeError, ExceptionMessages::indexExceedsMaximumBound("index", index, length()));
 128         return 0;
 129     }
 130     return m_ranges[index].m_end;
 131 }
 132
 133 void TimeRanges::add(double start, double end)
 134 {
 135     ASSERT(start <= end);
 136     unsigned overlappingArcIndex;
 137     Range addedRange(start, end);
 138
 139     // For each present range check if we need to:
 140     // - merge with the added range, in case we are overlapping or contiguous
 141     // - Need to insert in place, we we are completely, not overlapping and not contiguous
 142     // in between two ranges.
 143     //
 144     // TODO: Given that we assume that ranges are correctly ordered, this could be optimized.
 145
 146     for (overlappingArcIndex = 0; overlappingArcIndex < m_ranges.size(); overlappingArcIndex++) {
 147         if (addedRange.isOverlappingRange(m_ranges[overlappingArcIndex])
 148             || addedRange.isContiguousWithRange(m_ranges[overlappingArcIndex])) {
 149             // We need to merge the addedRange and that range.
 150             addedRange = addedRange.unionWithOverlappingOrContiguousRange(m_ranges[overlappingArcIndex]);
 151             m_ranges.remove(overlappingArcIndex);
 152             overlappingArcIndex--;
 153         } else {
 154             // Check the case for which there is no more to do
 155             if (!overlappingArcIndex) {
 156                 if (addedRange.isBeforeRange(m_ranges[0])) {
 157                     // First index, and we are completely before that range (and not contiguous, nor overlapping).
 158                     // We just need to be inserted here.
 159                     break;
 160                 }
 161             } else {
 162                 if (m_ranges[overlappingArcIndex - 1].isBeforeRange(addedRange)
 163                     && addedRange.isBeforeRange(m_ranges[overlappingArcIndex])) {
 164                     // We are exactly after the current previous range, and before the current range, while
 165                     // not overlapping with none of them. Insert here.
 166                     break;
 167                 }
 168             }
 169         }
 170     }
 171
 172     // Now that we are sure we don't overlap with any range, just add it.
 173     m_ranges.insert(overlappingArcIndex, addedRange);
 174 }
 175
 176 bool TimeRanges::contain(double time) const
 177 {
 178     for (unsigned n = 0; n < length(); n++) {
 179         if (time >= start(n, IGNORE_EXCEPTION) && time <= end(n, IGNORE_EXCEPTION))
 180             return true;
 181     }
 182     return false;
 183 }
 184
 185 double TimeRanges::nearest(double newPlaybackPosition, double currentPlaybackPosition) const
 186 {
 187     unsigned count = length();
 188     double bestMatch = 0;
 189     double bestDelta = std::numeric_limits<double>::infinity();
 190     for (unsigned ndx = 0; ndx < count; ndx++) {
 191         double startTime = start(ndx, IGNORE_EXCEPTION);
 192         double endTime = end(ndx, IGNORE_EXCEPTION);
 193         if (newPlaybackPosition >= startTime && newPlaybackPosition <= endTime)
 194             return newPlaybackPosition;
 195
 196         double delta, match;
 197         if (newPlaybackPosition < startTime) {
 198             delta = startTime - newPlaybackPosition;
 199             match = startTime;
 200         } else {
 201             delta = newPlaybackPosition - endTime;
 202             match = endTime;
 203         }
 204
 205         if (delta < bestDelta || (delta == bestDelta
 206             && std::abs(currentPlaybackPosition - match) < std::abs(currentPlaybackPosition - bestMatch))) {
 207             bestDelta = delta;
 208             bestMatch = match;
 209         }
 210     }
 211     return bestMatch;
 212 }