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/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2011 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 --> */
#ifndef D_SEG_LIST_H
#define D_SEG_LIST_H
#include <cstdlib>
#include <vector>
#include <limits>
#include <algorithm>
namespace aria2 {
template<typename T>
class SegList {
public:
SegList()
: index_(0), val_(std::numeric_limits<T>::min())
{}
void clear()
{
segs_.clear();
index_ = 0;
val_ = std::numeric_limits<T>::min();
}
// Transforms list of segments so that they are sorted ascending
// order of starting value and intersecting and touching segments
// are all merged into one. This function resets current position.
void normalize()
{
if(!segs_.empty()) {
std::sort(segs_.begin(), segs_.end());
std::vector<std::pair<T, T> > s;
s.push_back(segs_.front());
for(size_t i = 1, len = segs_.size(); i < len; ++i) {
const std::pair<T, T>& x = segs_[i];
if(x.first <= s.back().second) {
if(s.back().second < x.second) {
s.back().second = x.second;
}
} else {
s.push_back(x);
}
}
s.swap(segs_);
index_ = 0;
val_ = segs_.front().first;
}
}
// Add segment [a, b). If a >= b, do nothing.
void add(T a, T b)
{
if(a < b) {
if(segs_.empty()) {
val_ = std::max(val_, a);
}
segs_.push_back(std::make_pair(a, b));
}
}
// Returns true if next value is available. Otherwise returns false.
bool hasNext() const
{
return index_ < segs_.size() && val_ < segs_[index_].second;
}
// Returns next value. Advance current position to the next. If
// this fuction is called when hasNext() returns false, returns 0.
T next()
{
T res;
size_t len = segs_.size();
if(index_ < len) {
res = val_++;
if(val_ == segs_[index_].second) {
++index_;
if(index_ < len) {
val_ = segs_[index_].first;
}
}
} else {
res = 0;
}
return res;
}
// Returns next value. Current position is not advanced. If
// this fuction is called when hasNext() returns false, returns 0.
T peek() const
{
T res;
if(index_ < segs_.size()) {
res = val_;
} else {
res = 0;
}
return res;
}
private:
std::vector<std::pair<T, T> > segs_;
size_t index_;
T val_;
// Don't allow copying
SegList(const SegList<T>&);
SegList& operator=(const SegList<T>&);
};
} // namespace aria2
#endif // D_SEG_LIST_H
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