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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_RANGESET_H
#define CEPH_RANGESET_H
/*
*
* my first container with iterator! it's pretty ugly.
*
*/
#include <map>
//typedef int T;
template <class T>
struct _rangeset_base {
map<T,T> ranges; // pair(first,last) (inclusive, e.g. [first,last])
typedef typename map<T,T>::iterator mapit;
// get iterator for range including val. or ranges.end().
mapit get_range_for(T val) {
mapit it = ranges.lower_bound(val);
if (it == ranges.end()) {
// search backwards
typename map<T,T>::reverse_iterator it = ranges.rbegin();
if (it == ranges.rend()) return ranges.end();
if (it->first <= val && it->second >= val)
return ranges.find(it->first);
return ranges.end();
} else {
if (it->first == val) return
it--;
if (it->first <= val && it->second >= val)
return it;
return ranges.end();
}
}
};
template <class T>
class rangeset_iterator :
public std::iterator<std::input_iterator_tag, T>
{
//typedef typename map<T,T>::iterator mapit;
map<T,T> ranges;
typename map<T,T>::iterator it;
T current;
public:
// cons
rangeset_iterator() {}
rangeset_iterator(typename map<T,T>::iterator& it, map<T,T>& ranges) {
this->ranges = ranges;
this->it = it;
if (this->it != ranges.end())
current = it->first;
}
bool operator==(rangeset_iterator<T> rit) {
return (it == rit.it && rit.current == current);
}
bool operator!=(rangeset_iterator<T> rit) {
return (it != rit.it) || (rit.current != current);
}
T& operator*() {
return current;
}
rangeset_iterator<T> operator++(int) {
if (current < it->second)
current++;
else {
it++;
if (it != ranges.end())
current = it->first;
}
return *this;
}
};
template <class T>
class rangeset
{
typedef typename map<T,T>::iterator map_iterator;
_rangeset_base<T> theset;
inodeno_t _size;
public:
rangeset() { _size = 0; }
typedef rangeset_iterator<T> iterator;
iterator begin() {
map_iterator it = theset.ranges.begin();
return iterator(it, theset.ranges);
}
iterator end() {
map_iterator it = theset.ranges.end();
return iterator(it, theset.ranges);
}
map_iterator map_begin() {
return theset.ranges.begin();
}
map_iterator map_end() {
return theset.ranges.end();
}
int map_size() {
return theset.ranges.size();
}
void map_insert(T v1, T v2) {
theset.ranges.insert(pair<T,T>(v1,v2));
_size += v2 - v1+1;
}
// ...
bool contains(T val) {
if (theset.get_range_for(val) == theset.ranges.end()) return false;
ceph_assert(!empty());
return true;
}
void insert(T val) {
ceph_assert(!contains(val));
map_iterator left = theset.get_range_for(val-1);
map_iterator right = theset.get_range_for(val+1);
if (left != theset.ranges.end() &&
right != theset.ranges.end()) {
// join!
left->second = right->second;
theset.ranges.erase(right);
_size++;
return;
}
if (left != theset.ranges.end()) {
// add to left range
left->second = val;
_size++;
return;
}
if (right != theset.ranges.end()) {
// add to right range
theset.ranges.insert(pair<T,T>(val, right->second));
theset.ranges.erase(val+1);
_size++;
return;
}
// new range
theset.ranges.insert(pair<T,T>(val,val));
_size++;
return;
}
unsigned size() {
return size();
}
bool empty() {
if (theset.ranges.empty()) {
ceph_assert(_size == 0);
return true;
}
ceph_assert(_size>0);
return false;
}
T first() {
ceph_assert(!empty());
map_iterator it = theset.ranges.begin();
return it->first;
}
void erase(T val) {
ceph_assert(contains(val));
map_iterator it = theset.get_range_for(val);
ceph_assert(it != theset.ranges.end());
// entire range
if (val == it->first && val == it->second) {
theset.ranges.erase(it);
_size--;
return;
}
// beginning
if (val == it->first) {
theset.ranges.insert(pair<T,T>(val+1, it->second));
theset.ranges.erase(it);
_size--;
return;
}
// end
if (val == it->second) {
it->second = val-1;
_size--;
return;
}
// middle split
theset.ranges.insert(pair<T,T>(it->first, val-1));
theset.ranges.insert(pair<T,T>(val+1, it->second));
theset.ranges.erase(it);
_size--;
return;
}
void dump() {
for (typename map<T,T>::iterator it = theset.ranges.begin();
it != theset.ranges.end();
it++) {
cout << " " << it->first << "-" << it->second << endl;
}
}
};
#endif
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