mirror of https://github.com/aria2/aria2
94 lines
2.9 KiB
C++
94 lines
2.9 KiB
C++
/* <!-- copyright */
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/*
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* aria2 - The high speed download utility
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*
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* Copyright (C) 2009 Tatsuhiro Tsujikawa
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* In addition, as a special exception, the copyright holders give
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* permission to link the code of portions of this program with the
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* OpenSSL library under certain conditions as described in each
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* individual source file, and distribute linked combinations
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* including the two.
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* You must obey the GNU General Public License in all respects
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* for all of the code used other than OpenSSL. If you modify
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* file(s) with this exception, you may extend this exception to your
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* version of the file(s), but you are not obligated to do so. If you
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* do not wish to do so, delete this exception statement from your
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* version. If you delete this exception statement from all source
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* files in the program, then also delete it here.
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*/
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/* copyright --> */
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#include "LongestSequencePieceSelector.h"
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#include "bitfield.h"
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namespace aria2 {
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namespace {
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size_t getStartIndex(size_t from, const unsigned char* bitfield, size_t nbits)
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{
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while (from < nbits && !bitfield::test(bitfield, nbits, from)) {
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++from;
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}
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if (nbits <= from) {
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return nbits;
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}
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else {
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return from;
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}
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}
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} // namespace
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namespace {
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size_t getEndIndex(size_t from, const unsigned char* bitfield, size_t nbits)
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{
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while (from < nbits && bitfield::test(bitfield, nbits, from)) {
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++from;
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}
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return from;
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}
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} // namespace
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bool LongestSequencePieceSelector::select(size_t& index,
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const unsigned char* bitfield,
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size_t nbits) const
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{
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size_t mstartindex = 0;
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size_t mendindex = 0;
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size_t nextIndex = 0;
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while (nextIndex < nbits) {
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size_t startindex = getStartIndex(nextIndex, bitfield, nbits);
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if (startindex == nbits) {
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break;
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}
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size_t endindex = getEndIndex(startindex, bitfield, nbits);
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if (mendindex - mstartindex < endindex - startindex) {
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mstartindex = startindex;
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mendindex = endindex;
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}
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nextIndex = endindex;
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}
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if (mendindex - mstartindex > 0) {
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index = mendindex - 1;
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return true;
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}
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else {
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return false;
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}
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}
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} // namespace aria2
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