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/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2009 Tatsuhiro Tsujikawa
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "LongestSequencePieceSelector.h"
#include "bitfield.h"
namespace aria2 {
namespace {
size_t getStartIndex(size_t from, const unsigned char* bitfield, size_t nbits)
{
while (from < nbits && !bitfield::test(bitfield, nbits, from)) {
++from;
}
if (nbits <= from) {
return nbits;
}
else {
return from;
}
}
} // namespace
namespace {
size_t getEndIndex(size_t from, const unsigned char* bitfield, size_t nbits)
{
while (from < nbits && bitfield::test(bitfield, nbits, from)) {
++from;
}
return from;
}
} // namespace
bool LongestSequencePieceSelector::select(size_t& index,
const unsigned char* bitfield,
size_t nbits) const
{
size_t mstartindex = 0;
size_t mendindex = 0;
size_t nextIndex = 0;
while (nextIndex < nbits) {
size_t startindex = getStartIndex(nextIndex, bitfield, nbits);
if (startindex == nbits) {
break;
}
size_t endindex = getEndIndex(startindex, bitfield, nbits);
if (mendindex - mstartindex < endindex - startindex) {
mstartindex = startindex;
mendindex = endindex;
}
nextIndex = endindex;
}
if (mendindex - mstartindex > 0) {
index = mendindex - 1;
return true;
}
else {
return false;
}
}
} // namespace aria2
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