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      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 PassRefPtrWillBeRawPtr<TimeRanges> TimeRanges::create(const blink::WebTimeRanges& webRanges)
     43 {
     44     RefPtrWillBeRawPtr<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.release();
     51 }
     52 
     53 PassRefPtrWillBeRawPtr<TimeRanges> TimeRanges::copy() const
     54 {
     55     RefPtrWillBeRawPtr<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.release();
     62 }
     63 
     64 void TimeRanges::invert()
     65 {
     66     RefPtrWillBeRawPtr<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     RefPtrWillBeRawPtr<TimeRanges> invertedOther = other->copy();
     96     invertedOther->invert();
     97 
     98     invert();
     99     unionWith(invertedOther.get());
    100     invert();
    101 }
    102 
    103 void TimeRanges::unionWith(const TimeRanges* other)
    104 {
    105     ASSERT(other);
    106     RefPtrWillBeRawPtr<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 }
    213 
    214 void TimeRanges::trace(Visitor* visitor)
    215 {
    216     visitor->trace(m_ranges);
    217 }
    218