--- /dev/null
+// -*- 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_BTREE_INTERVAL_SET_H
+#define CEPH_BTREE_INTERVAL_SET_H
+
+#include <iterator>
+#include <map>
+#include <ostream>
+
+#include "encoding.h"
+
+#ifndef MIN
+# define MIN(a,b) ((a)<=(b) ? (a):(b))
+#endif
+#ifndef MAX
+# define MAX(a,b) ((a)>=(b) ? (a):(b))
+#endif
+
+#include "cpp-btree/btree_map.h"
+#include "assert.h"
+#include "encoding_btree.h"
+
+template<typename T,
+ typename Alloc = std::allocator<std::pair<const T, T>>>
+class btree_interval_set {
+ public:
+
+ typedef btree::btree_map<T,T, std::less<T>, Alloc> map_t;
+
+ class const_iterator;
+
+ class iterator : public std::iterator <std::forward_iterator_tag, T>
+ {
+ public:
+ explicit iterator(typename map_t::iterator iter)
+ : _iter(iter)
+ { }
+
+ // For the copy constructor and assignment operator, the compiler-generated functions, which
+ // perform simple bitwise copying, should be fine.
+
+ bool operator==(const iterator& rhs) const {
+ return (_iter == rhs._iter);
+ }
+
+ bool operator!=(const iterator& rhs) const {
+ return (_iter != rhs._iter);
+ }
+
+ // Dereference this iterator to get a pair.
+ std::pair < T, T > &operator*() {
+ return *_iter;
+ }
+
+ // Return the interval start.
+ T get_start() const {
+ return _iter->first;
+ }
+
+ // Return the interval length.
+ T get_len() const {
+ return _iter->second;
+ }
+
+ // Set the interval length.
+ void set_len(T len) {
+ _iter->second = len;
+ }
+
+ // Preincrement
+ iterator &operator++()
+ {
+ ++_iter;
+ return *this;
+ }
+
+ // Postincrement
+ iterator operator++(int)
+ {
+ iterator prev(_iter);
+ ++_iter;
+ return prev;
+ }
+
+ friend class btree_interval_set<T>::const_iterator;
+
+ protected:
+ typename map_t::iterator _iter;
+ friend class btree_interval_set<T>;
+ };
+
+ class const_iterator : public std::iterator <std::forward_iterator_tag, T>
+ {
+ public:
+ explicit const_iterator(typename map_t::const_iterator iter)
+ : _iter(iter)
+ { }
+
+ const_iterator(const iterator &i)
+ : _iter(i._iter)
+ { }
+
+ // For the copy constructor and assignment operator, the compiler-generated functions, which
+ // perform simple bitwise copying, should be fine.
+
+ bool operator==(const const_iterator& rhs) const {
+ return (_iter == rhs._iter);
+ }
+
+ bool operator!=(const const_iterator& rhs) const {
+ return (_iter != rhs._iter);
+ }
+
+ // Dereference this iterator to get a pair.
+ std::pair < T, T > operator*() const {
+ return *_iter;
+ }
+
+ // Return the interval start.
+ T get_start() const {
+ return _iter->first;
+ }
+
+ // Return the interval length.
+ T get_len() const {
+ return _iter->second;
+ }
+
+ // Preincrement
+ const_iterator &operator++()
+ {
+ ++_iter;
+ return *this;
+ }
+
+ // Postincrement
+ const_iterator operator++(int)
+ {
+ const_iterator prev(_iter);
+ ++_iter;
+ return prev;
+ }
+
+ protected:
+ typename map_t::const_iterator _iter;
+ };
+
+ btree_interval_set() : _size(0) {}
+
+ int num_intervals() const
+ {
+ return m.size();
+ }
+
+ typename btree_interval_set<T,Alloc>::iterator begin() {
+ return typename btree_interval_set<T,Alloc>::iterator(m.begin());
+ }
+
+ typename btree_interval_set<T,Alloc>::iterator lower_bound(T start) {
+ return typename btree_interval_set<T,Alloc>::iterator(find_inc_m(start));
+ }
+
+ typename btree_interval_set<T,Alloc>::iterator end() {
+ return typename btree_interval_set<T,Alloc>::iterator(m.end());
+ }
+
+ typename btree_interval_set<T,Alloc>::const_iterator begin() const {
+ return typename btree_interval_set<T,Alloc>::const_iterator(m.begin());
+ }
+
+ typename btree_interval_set<T,Alloc>::const_iterator lower_bound(T start) const {
+ return typename btree_interval_set<T,Alloc>::const_iterator(find_inc(start));
+ }
+
+ typename btree_interval_set<T,Alloc>::const_iterator end() const {
+ return typename btree_interval_set<T,Alloc>::const_iterator(m.end());
+ }
+
+ // helpers
+ private:
+ typename map_t::const_iterator find_inc(T start) const {
+ typename map_t::const_iterator p = m.lower_bound(start); // p->first >= start
+ if (p != m.begin() &&
+ (p == m.end() || p->first > start)) {
+ p--; // might overlap?
+ if (p->first + p->second <= start)
+ p++; // it doesn't.
+ }
+ return p;
+ }
+
+ typename map_t::iterator find_inc_m(T start) {
+ typename map_t::iterator p = m.lower_bound(start);
+ if (p != m.begin() &&
+ (p == m.end() || p->first > start)) {
+ p--; // might overlap?
+ if (p->first + p->second <= start)
+ p++; // it doesn't.
+ }
+ return p;
+ }
+
+ typename map_t::const_iterator find_adj(T start) const {
+ typename map_t::const_iterator p = m.lower_bound(start);
+ if (p != m.begin() &&
+ (p == m.end() || p->first > start)) {
+ p--; // might touch?
+ if (p->first + p->second < start)
+ p++; // it doesn't.
+ }
+ return p;
+ }
+
+ typename map_t::iterator find_adj_m(T start) {
+ typename map_t::iterator p = m.lower_bound(start);
+ if (p != m.begin() &&
+ (p == m.end() || p->first > start)) {
+ p--; // might touch?
+ if (p->first + p->second < start)
+ p++; // it doesn't.
+ }
+ return p;
+ }
+
+ public:
+ bool operator==(const btree_interval_set& other) const {
+ return _size == other._size && m == other.m;
+ }
+
+ int64_t size() const {
+ return _size;
+ }
+
+ void encode(bufferlist& bl) const {
+ ::encode(m, bl);
+ }
+ void encode_nohead(bufferlist& bl) const {
+ ::encode_nohead(m, bl);
+ }
+ void decode(bufferlist::iterator& bl) {
+ ::decode(m, bl);
+ _size = 0;
+ for (typename map_t::const_iterator p = m.begin();
+ p != m.end();
+ p++)
+ _size += p->second;
+ }
+ void decode_nohead(int n, bufferlist::iterator& bl) {
+ ::decode_nohead(n, m, bl);
+ _size = 0;
+ for (typename map_t::const_iterator p = m.begin();
+ p != m.end();
+ p++)
+ _size += p->second;
+ }
+
+ void clear() {
+ m.clear();
+ _size = 0;
+ }
+
+ bool contains(T i, T *pstart=0, T *plen=0) const {
+ typename map_t::const_iterator p = find_inc(i);
+ if (p == m.end()) return false;
+ if (p->first > i) return false;
+ if (p->first+p->second <= i) return false;
+ assert(p->first <= i && p->first+p->second > i);
+ if (pstart)
+ *pstart = p->first;
+ if (plen)
+ *plen = p->second;
+ return true;
+ }
+ bool contains(T start, T len) const {
+ typename map_t::const_iterator p = find_inc(start);
+ if (p == m.end()) return false;
+ if (p->first > start) return false;
+ if (p->first+p->second <= start) return false;
+ assert(p->first <= start && p->first+p->second > start);
+ if (p->first+p->second < start+len) return false;
+ return true;
+ }
+ bool intersects(T start, T len) const {
+ btree_interval_set a;
+ a.insert(start, len);
+ btree_interval_set i;
+ i.intersection_of( *this, a );
+ if (i.empty()) return false;
+ return true;
+ }
+
+ // outer range of set
+ bool empty() const {
+ return m.empty();
+ }
+ T range_start() const {
+ assert(!empty());
+ typename map_t::const_iterator p = m.begin();
+ return p->first;
+ }
+ T range_end() const {
+ assert(!empty());
+ typename map_t::const_iterator p = m.end();
+ p--;
+ return p->first+p->second;
+ }
+
+ // interval start after p (where p not in set)
+ bool starts_after(T i) const {
+ assert(!contains(i));
+ typename map_t::const_iterator p = find_inc(i);
+ if (p == m.end()) return false;
+ return true;
+ }
+ T start_after(T i) const {
+ assert(!contains(i));
+ typename map_t::const_iterator p = find_inc(i);
+ return p->first;
+ }
+
+ // interval end that contains start
+ T end_after(T start) const {
+ assert(contains(start));
+ typename map_t::const_iterator p = find_inc(start);
+ return p->first+p->second;
+ }
+
+ void insert(T val) {
+ insert(val, 1);
+ }
+
+ void insert(T start, T len, T *pstart=0, T *plen=0) {
+ //cout << "insert " << start << "~" << len << endl;
+ assert(len > 0);
+ _size += len;
+ typename map_t::iterator p = find_adj_m(start);
+ if (p == m.end()) {
+ m[start] = len; // new interval
+ if (pstart)
+ *pstart = start;
+ if (plen)
+ *plen = len;
+ } else {
+ if (p->first < start) {
+
+ if (p->first + p->second != start) {
+ //cout << "p is " << p->first << "~" << p->second << ", start is " << start << ", len is " << len << endl;
+ ceph_abort();
+ }
+
+ p->second += len; // append to end
+
+ typename map_t::iterator n = p;
+ n++;
+ if (pstart)
+ *pstart = p->first;
+ if (n != m.end() &&
+ start+len == n->first) { // combine with next, too!
+ p->second += n->second;
+ if (plen)
+ *plen = p->second;
+ m.erase(n);
+ } else {
+ if (plen)
+ *plen = p->second;
+ }
+ } else {
+ if (start+len == p->first) {
+ if (pstart)
+ *pstart = start;
+ if (plen)
+ *plen = len + p->second;
+ T plen = p->second;
+ m.erase(p);
+ m[start] = len + plen; // append to front
+ } else {
+ assert(p->first > start+len);
+ if (pstart)
+ *pstart = start;
+ if (plen)
+ *plen = len;
+ m[start] = len; // new interval
+ }
+ }
+ }
+ }
+
+ void swap(btree_interval_set<T>& other) {
+ m.swap(other.m);
+ std::swap(_size, other._size);
+ }
+
+ void erase(iterator &i) {
+ _size -= i.get_len();
+ assert(_size >= 0);
+ m.erase(i._iter);
+ }
+
+ void erase(T val) {
+ erase(val, 1);
+ }
+
+ void erase(T start, T len) {
+ typename map_t::iterator p = find_inc_m(start);
+
+ _size -= len;
+ assert(_size >= 0);
+
+ assert(p != m.end());
+ assert(p->first <= start);
+
+ T before = start - p->first;
+ assert(p->second >= before+len);
+ T after = p->second - before - len;
+
+ if (before)
+ p->second = before; // shorten bit before
+ else
+ m.erase(p);
+ if (after)
+ m[start+len] = after;
+ }
+
+
+ void subtract(const btree_interval_set &a) {
+ for (typename map_t::const_iterator p = a.m.begin();
+ p != a.m.end();
+ p++)
+ erase(p->first, p->second);
+ }
+
+ void insert(const btree_interval_set &a) {
+ for (typename map_t::const_iterator p = a.m.begin();
+ p != a.m.end();
+ p++)
+ insert(p->first, p->second);
+ }
+
+
+ void intersection_of(const btree_interval_set &a, const btree_interval_set &b) {
+ assert(&a != this);
+ assert(&b != this);
+ clear();
+
+ typename map_t::const_iterator pa = a.m.begin();
+ typename map_t::const_iterator pb = b.m.begin();
+
+ while (pa != a.m.end() && pb != b.m.end()) {
+ // passing?
+ if (pa->first + pa->second <= pb->first)
+ { pa++; continue; }
+ if (pb->first + pb->second <= pa->first)
+ { pb++; continue; }
+ T start = MAX(pa->first, pb->first);
+ T en = MIN(pa->first+pa->second, pb->first+pb->second);
+ assert(en > start);
+ insert(start, en-start);
+ if (pa->first+pa->second > pb->first+pb->second)
+ pb++;
+ else
+ pa++;
+ }
+ }
+ void intersection_of(const btree_interval_set& b) {
+ btree_interval_set a;
+ swap(a);
+ intersection_of(a, b);
+ }
+
+ void union_of(const btree_interval_set &a, const btree_interval_set &b) {
+ assert(&a != this);
+ assert(&b != this);
+ clear();
+
+ //cout << "union_of" << endl;
+
+ // a
+ m = a.m;
+ _size = a._size;
+
+ // - (a*b)
+ btree_interval_set ab;
+ ab.intersection_of(a, b);
+ subtract(ab);
+
+ // + b
+ insert(b);
+ return;
+ }
+ void union_of(const btree_interval_set &b) {
+ btree_interval_set a;
+ swap(a);
+ union_of(a, b);
+ }
+
+ bool subset_of(const btree_interval_set &big) const {
+ for (typename map_t::const_iterator i = m.begin();
+ i != m.end();
+ i++)
+ if (!big.contains(i->first, i->second)) return false;
+ return true;
+ }
+
+ /*
+ * build a subset of @other, starting at or after @start, and including
+ * @len worth of values, skipping holes. e.g.,
+ * span_of([5~10,20~5], 8, 5) -> [8~2,20~3]
+ */
+ void span_of(const btree_interval_set &other, T start, T len) {
+ clear();
+ typename map_t::const_iterator p = other.find_inc(start);
+ if (p == other.m.end())
+ return;
+ if (p->first < start) {
+ if (p->first + p->second < start)
+ return;
+ if (p->first + p->second < start + len) {
+ T howmuch = p->second - (start - p->first);
+ insert(start, howmuch);
+ len -= howmuch;
+ p++;
+ } else {
+ insert(start, len);
+ return;
+ }
+ }
+ while (p != other.m.end() && len > 0) {
+ if (p->second < len) {
+ insert(p->first, p->second);
+ len -= p->second;
+ p++;
+ } else {
+ insert(p->first, len);
+ return;
+ }
+ }
+ }
+
+private:
+ // data
+ int64_t _size;
+ map_t m; // map start -> len
+};
+
+
+template<class T, class A>
+inline std::ostream& operator<<(std::ostream& out, const btree_interval_set<T,A> &s) {
+ out << "[";
+ const char *prequel = "";
+ for (auto i = s.begin();
+ i != s.end();
+ ++i)
+ {
+ out << prequel << i.get_start() << "~" << i.get_len();
+ prequel = ",";
+ }
+ out << "]";
+ return out;
+}
+
+template<class T,typename A>
+inline void encode(const btree_interval_set<T,A>& s, bufferlist& bl)
+{
+ s.encode(bl);
+}
+template<class T,typename A>
+inline void decode(btree_interval_set<T,A>& s, bufferlist::iterator& p)
+{
+ s.decode(p);
+}
+
+#endif
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