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/*
* Copyright (C) 2011 Nicolas Bonnefon and other contributors
*
* This file is part of glogg.
*
* glogg is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* glogg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with glogg. If not, see <http://www.gnu.org/licenses/>.
*/
// Use a bisection method to find the given line number
// in a sorted list.
// The T type must be a container containing elements that
// implement the lineNumber() member.
// Returns true if the lineNumber is found, false if not
// foundIndex is the index of the found number or the index
// of the closest greater element.
template <typename T> bool lookupLineNumber(
const T& list, qint64 lineNumber, int* foundIndex )
{
int minIndex = 0;
int maxIndex = list.size() - 1;
// If the list is not empty
if ( maxIndex - minIndex >= 0 ) {
// First we test the ends
if ( list[minIndex].lineNumber() == lineNumber ) {
*foundIndex = minIndex;
return true;
}
else if ( list[maxIndex].lineNumber() == lineNumber ) {
*foundIndex = maxIndex;
return true;
}
// Then we test the rest
while ( (maxIndex - minIndex) > 1 ) {
const int tryIndex = (minIndex + maxIndex) / 2;
const qint64 currentMatchingNumber =
list[tryIndex].lineNumber();
if ( currentMatchingNumber > lineNumber )
maxIndex = tryIndex;
else if ( currentMatchingNumber < lineNumber )
minIndex = tryIndex;
else if ( currentMatchingNumber == lineNumber ) {
*foundIndex = tryIndex;
return true;
}
}
// If we haven't found anything...
// ... end of the list or before the next
if ( lineNumber > list[maxIndex].lineNumber() )
*foundIndex = maxIndex + 1;
else if ( lineNumber > list[minIndex].lineNumber() )
*foundIndex = minIndex + 1;
else
*foundIndex = minIndex;
}
else {
*foundIndex = 0;
}
return false;
}
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