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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 
     28 #include "TimeRanges.h"
     29 
     30 #include <math.h>
     31 
     32 using namespace WebCore;
     33 
     34 TimeRanges::TimeRanges(float start, float end)
     35 {
     36     add(start, end);
     37 }
     38 
     39 PassRefPtr<TimeRanges> TimeRanges::copy()
     40 {
     41     RefPtr<TimeRanges> newSession = TimeRanges::create();
     42 
     43     unsigned size = m_ranges.size();
     44     for (unsigned i = 0; i < size; i++)
     45         newSession->add(m_ranges[i].m_start, m_ranges[i].m_end);
     46 
     47     return newSession.release();
     48 }
     49 
     50 float TimeRanges::start(unsigned index, ExceptionCode& ec) const
     51 {
     52     if (index >= length()) {
     53         ec = INDEX_SIZE_ERR;
     54         return 0;
     55     }
     56     return m_ranges[index].m_start;
     57 }
     58 
     59 float TimeRanges::end(unsigned index, ExceptionCode& ec) const
     60 {
     61     if (index >= length()) {
     62         ec = INDEX_SIZE_ERR;
     63         return 0;
     64     }
     65     return m_ranges[index].m_end;
     66 }
     67 
     68 void TimeRanges::add(float start, float end)
     69 {
     70     ASSERT(start <= end);
     71     unsigned int overlappingArcIndex;
     72     Range addedRange(start, end);
     73 
     74     // For each present range check if we need to:
     75     // - merge with the added range, in case we are overlapping or contiguous
     76     // - Need to insert in place, we we are completely, not overlapping and not contiguous
     77     // in between two ranges.
     78     //
     79     // TODO: Given that we assume that ranges are correctly ordered, this could be optimized.
     80 
     81     for (overlappingArcIndex = 0; overlappingArcIndex < m_ranges.size(); overlappingArcIndex++) {
     82         if (addedRange.isOverlappingRange(m_ranges[overlappingArcIndex])
     83          || addedRange.isContiguousWithRange(m_ranges[overlappingArcIndex])) {
     84             // We need to merge the addedRange and that range.
     85             addedRange = addedRange.unionWithOverlappingOrContiguousRange(m_ranges[overlappingArcIndex]);
     86             m_ranges.remove(overlappingArcIndex);
     87             overlappingArcIndex--;
     88         } else {
     89             // Check the case for which there is no more to do
     90             if (!overlappingArcIndex) {
     91                 if (addedRange.isBeforeRange(m_ranges[0])) {
     92                     // First index, and we are completely before that range (and not contiguous, nor overlapping).
     93                     // We just need to be inserted here.
     94                     break;
     95                 }
     96             } else {
     97                 if (m_ranges[overlappingArcIndex - 1].isBeforeRange(addedRange)
     98                  && addedRange.isBeforeRange(m_ranges[overlappingArcIndex])) {
     99                     // We are exactly after the current previous range, and before the current range, while
    100                     // not overlapping with none of them. Insert here.
    101                     break;
    102                 }
    103             }
    104         }
    105     }
    106 
    107     // Now that we are sure we don't overlap with any range, just add it.
    108     m_ranges.insert(overlappingArcIndex, addedRange);
    109 }
    110 
    111 bool TimeRanges::contain(float time) const
    112 {
    113     ExceptionCode unused;
    114     for (unsigned n = 0; n < length(); n++) {
    115         if (time >= start(n, unused) && time <= end(n, unused))
    116             return true;
    117     }
    118     return false;
    119 }
    120 
    121 float TimeRanges::nearest(float time) const
    122 {
    123     ExceptionCode unused;
    124     float closest = 0;
    125     unsigned count = length();
    126     for (unsigned ndx = 0; ndx < count; ndx++) {
    127         float startTime = start(ndx, unused);
    128         float endTime = end(ndx, unused);
    129         if (time >= startTime && time <= endTime)
    130             return time;
    131         if (fabs(startTime - time) < closest)
    132             closest = fabsf(startTime - time);
    133         else if (fabs(endTime - time) < closest)
    134             closest = fabsf(endTime - time);
    135     }
    136     return closest;
    137 }
    138