Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 824 insertions, 0 deletions

diff --git a/src/include/interval_set.h b/src/include/interval_set.h
new file mode 100644
index 000000000..dfb2a306c
--- /dev/null
+++ b/src/include/interval_set.h
@@ -0,0 +1,824 @@
+// -*- 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_INTERVAL_SET_H
+#define CEPH_INTERVAL_SET_H
+
+#include <iterator>
+#include <map>
+#include <ostream>
+
+#include "encoding.h"
+
+/*
+ * *** NOTE ***
+ *
+ * This class is written to work with a variety of map-like containers,
+ * *include* ones that invalidate iterators when they are modified (e.g.,
+ * flat_map and btree_map).
+ */
+
+template<typename T, template<typename, typename, typename ...> class C = std::map>
+class interval_set {
+ public:
+  using Map = C<T, T>;
+  using value_type = typename Map::value_type;
+  using offset_type = T;
+  using length_type = T;
+  using reference = value_type&;
+  using const_reference = const value_type&;
+  using size_type = typename Map::size_type;
+
+  class const_iterator;
+
+  class iterator
+  {
+    public:
+        using difference_type = ssize_t;
+        using value_type = typename Map::value_type;
+        using pointer = typename Map::value_type*;
+        using reference = typename Map::value_type&;
+        using iterator_category = std::forward_iterator_tag;
+
+        explicit iterator(typename Map::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.
+        reference operator*() const {
+          return *_iter;
+        }
+
+        // Return the interval start.
+        offset_type get_start() const {
+          return _iter->first;
+        }
+
+        // Return the interval length.
+        length_type get_len() const {
+          return _iter->second;
+        }
+
+        offset_type get_end() const {
+          return _iter->first + _iter->second;
+        }
+
+        // Set the interval length.
+        void set_len(const length_type& len) {
+          _iter->second = len;
+        }
+
+        // Preincrement
+        iterator& operator++()
+        {
+          ++_iter;
+          return *this;
+        }
+
+        // Postincrement
+        iterator operator++(int)
+        {
+          iterator prev(_iter);
+          ++_iter;
+          return prev;
+        }
+
+        // Predecrement
+        iterator& operator--()
+        {
+          --_iter;
+          return *this;
+        }
+
+        // Postdecrement
+        iterator operator--(int)
+        {
+          iterator prev(_iter);
+          --_iter;
+          return prev;
+        }
+
+    friend class interval_set::const_iterator;
+
+    protected:
+        typename Map::iterator _iter;
+    friend class interval_set;
+  };
+
+  class const_iterator
+  {
+    public:
+        using difference_type = ssize_t;
+        using value_type = const typename Map::value_type;
+        using pointer = const typename Map::value_type*;
+        using reference = const typename Map::value_type&;
+        using iterator_category = std::forward_iterator_tag;
+
+        explicit const_iterator(typename Map::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.
+        reference operator*() const {
+          return *_iter;
+        }
+
+        // Return the interval start.
+        offset_type get_start() const {
+          return _iter->first;
+        }
+        offset_type get_end() const {
+          return _iter->first + _iter->second;
+        }
+
+        // Return the interval length.
+        length_type 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;
+        }
+
+        // Predecrement
+        iterator& operator--()
+        {
+          --_iter;
+          return *this;
+        }
+
+        // Postdecrement
+        iterator operator--(int)
+        {
+          iterator prev(_iter);
+          --_iter;
+          return prev;
+        }
+
+    protected:
+        typename Map::const_iterator _iter;
+  };
+
+  interval_set() = default;
+  interval_set(Map&& other) {
+    m.swap(other);
+    for (const auto& p : m) {
+      _size += p.second;
+    }
+  }
+
+  size_type num_intervals() const
+  {
+    return m.size();
+  }
+
+  iterator begin() {
+    return iterator(m.begin());
+  }
+
+  iterator lower_bound(T start) {
+    return iterator(find_inc_m(start));
+  }
+
+  iterator end() {
+    return iterator(m.end());
+  }
+
+  const_iterator begin() const {
+    return const_iterator(m.begin());
+  }
+
+  const_iterator lower_bound(T start) const {
+    return const_iterator(find_inc(start));
+  }
+
+  const_iterator end() const {
+    return const_iterator(m.end());
+  }
+
+  // helpers
+ private:
+  auto find_inc(T start) const {
+    auto 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;
+  }
+  
+  auto find_inc_m(T start) {
+    auto 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;
+  }
+  
+  auto find_adj(T start) const {
+    auto 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;
+  }
+  
+  auto find_adj_m(T start) {
+    auto 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;
+  }
+
+  void intersection_size_asym(const interval_set &s, const interval_set &l) {
+    auto ps = s.m.begin();
+    ceph_assert(ps != s.m.end());
+    auto offset = ps->first;
+    bool first = true;
+    auto mi = m.begin();
+
+    while (1) {
+      if (first)
+        first = false;
+      auto pl = l.find_inc(offset);
+      if (pl == l.m.end())
+        break;
+      while (ps != s.m.end() && ps->first + ps->second <= pl->first)
+        ++ps;
+      if (ps == s.m.end())
+        break;
+      offset = pl->first + pl->second;
+      if (offset <= ps->first) {
+        offset = ps->first;
+        continue;
+      }
+
+      if (*ps == *pl) {
+        do {
+          mi = m.insert(mi, *ps);
+          _size += ps->second;
+          ++ps;
+          ++pl;
+        } while (ps != s.m.end() && pl != l.m.end() && *ps == *pl);
+        if (ps == s.m.end())
+          break;
+        offset = ps->first;
+        continue;
+      }
+
+      auto start = std::max<T>(ps->first, pl->first);
+      auto en = std::min<T>(ps->first + ps->second, offset);
+      ceph_assert(en > start);
+      mi = m.emplace_hint(mi, start, en - start);
+      _size += mi->second;
+      if (ps->first + ps->second <= offset) {
+        ++ps;
+        if (ps == s.m.end())
+          break;
+        offset = ps->first;
+      }
+    }
+  }
+
+  bool subset_size_sym(const interval_set &b) const {
+    auto pa = m.begin(), pb = b.m.begin();
+    const auto a_end = m.end(), b_end = b.m.end();
+
+    while (pa != a_end && pb != b_end) {
+      while (pb->first + pb->second <= pa->first) {
+        ++pb;
+        if (pb == b_end)
+          return false;
+      }
+
+      if (*pa == *pb) {
+        do {
+          ++pa;
+          ++pb;
+        } while (pa != a_end && pb != b_end && *pa == *pb);
+        continue;
+      }
+
+      // interval begins before other
+      if (pa->first < pb->first)
+        return false;
+      // interval is longer than other
+      if (pa->first + pa->second > pb->first + pb->second)
+        return false;
+
+      ++pa;
+    }
+
+    return pa == a_end;
+  }
+  
+ public:
+  bool operator==(const interval_set& other) const {
+    return _size == other._size && m == other.m;
+  }
+
+  uint64_t size() const {
+    return _size;
+  }
+
+  void bound_encode(size_t& p) const {
+    denc_traits<Map>::bound_encode(m, p);
+  }
+  void encode(ceph::buffer::list::contiguous_appender& p) const {
+    denc(m, p);
+  }
+  void decode(ceph::buffer::ptr::const_iterator& p) {
+    denc(m, p);
+    _size = 0;
+    for (const auto& p : m) {
+      _size += p.second;
+    }
+  }
+  void decode(ceph::buffer::list::iterator& p) {
+    denc(m, p);
+    _size = 0;
+    for (const auto& p : m) {
+      _size += p.second;
+    }
+  }
+
+  void encode_nohead(ceph::buffer::list::contiguous_appender& p) const {
+    denc_traits<Map>::encode_nohead(m, p);
+  }
+  void decode_nohead(int n, ceph::buffer::ptr::const_iterator& p) {
+    denc_traits<Map>::decode_nohead(n, m, p);
+    _size = 0;
+    for (const auto& p : m) {
+      _size += p.second;
+    }
+  }
+
+  void clear() {
+    m.clear();
+    _size = 0;
+  }
+
+  bool contains(T i, T *pstart=0, T *plen=0) const {
+    auto p = find_inc(i);
+    if (p == m.end()) return false;
+    if (p->first > i) return false;
+    if (p->first+p->second <= i) return false;
+    ceph_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 {
+    auto p = find_inc(start);
+    if (p == m.end()) return false;
+    if (p->first > start) return false;
+    if (p->first+p->second <= start) return false;
+    ceph_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 {
+    interval_set a;
+    a.insert(start, len);
+    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();
+  }
+  offset_type range_start() const {
+    ceph_assert(!empty());
+    auto p = m.begin();
+    return p->first;
+  }
+  offset_type range_end() const {
+    ceph_assert(!empty());
+    auto p = m.rbegin();
+    return p->first + p->second;
+  }
+
+  // interval start after p (where p not in set)
+  bool starts_after(T i) const {
+    ceph_assert(!contains(i));
+    auto p = find_inc(i);
+    if (p == m.end()) return false;
+    return true;
+  }
+  offset_type start_after(T i) const {
+    ceph_assert(!contains(i));
+    auto p = find_inc(i);
+    return p->first;
+  }
+
+  // interval end that contains start
+  offset_type end_after(T start) const {
+    ceph_assert(contains(start));
+    auto 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;
+    ceph_assert(len > 0);
+    _size += len;
+    auto 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
+        
+        auto 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 psecond = p->second;
+          m.erase(p);
+          m[start] = len + psecond;  // append to front
+        } else {
+          ceph_assert(p->first > start+len);
+	  if (pstart)
+	    *pstart = start;
+	  if (plen)
+	    *plen = len;
+          m[start] = len;              // new interval
+        }
+      }
+    }
+  }
+
+  void swap(interval_set& other) {
+    m.swap(other.m);
+    std::swap(_size, other._size);
+  }    
+  
+  void erase(const iterator &i) {
+    _size -= i.get_len();
+    m.erase(i._iter);
+  }
+
+  void erase(T val) {
+    erase(val, 1);
+  }
+
+  void erase(T start, T len, 
+    std::function<bool(T, T)> claim = {}) {
+    auto p = find_inc_m(start);
+
+    _size -= len;
+
+    ceph_assert(p != m.end());
+    ceph_assert(p->first <= start);
+
+    T before = start - p->first;
+    ceph_assert(p->second >= before+len);
+    T after = p->second - before - len;
+    if (before) {
+      if (claim && claim(p->first, before)) {
+	_size -= before;
+	m.erase(p);
+      } else {
+	p->second = before;        // shorten bit before
+      }
+    } else {
+      m.erase(p);
+    }
+    if (after) {
+      if (claim && claim(start + len, after)) {
+	_size -= after;
+      } else {
+	m[start + len] = after;
+      }
+    }
+  }
+
+  void subtract(const interval_set &a) {
+    for (const auto& [start, len] : a.m) {
+      erase(start, len);
+    }
+  }
+
+  void insert(const interval_set &a) {
+    for (const auto& [start, len] : a.m) {
+      insert(start, len);
+    }
+  }
+
+
+  void intersection_of(const interval_set &a, const interval_set &b) {
+    ceph_assert(&a != this);
+    ceph_assert(&b != this);
+    clear();
+
+    const interval_set *s, *l;
+
+    if (a.size() < b.size()) {
+      s = &a;
+      l = &b;
+    } else {
+      s = &b;
+      l = &a;
+    }
+
+    if (!s->size())
+      return;
+
+    /*
+     * Use the lower_bound algorithm for larger size ratios
+     * where it performs better, but not for smaller size
+     * ratios where sequential search performs better.
+     */
+    if (l->size() / s->size() >= 10) {
+      intersection_size_asym(*s, *l);
+      return;
+    }
+
+    auto pa = a.m.begin();
+    auto pb = b.m.begin();
+    auto mi = 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; }
+
+      if (*pa == *pb) {
+        do {
+          mi = m.insert(mi, *pa);
+          _size += pa->second;
+          ++pa;
+          ++pb;
+        } while (pa != a.m.end() && pb != b.m.end() && *pa == *pb);
+        continue;
+      }
+
+      T start = std::max(pa->first, pb->first);
+      T en = std::min(pa->first+pa->second, pb->first+pb->second);
+      ceph_assert(en > start);
+      mi = m.emplace_hint(mi, start, en - start);
+      _size += mi->second;
+      if (pa->first+pa->second > pb->first+pb->second)
+        pb++;
+      else
+        pa++; 
+    }
+  }
+  void intersection_of(const interval_set& b) {
+    interval_set a;
+    swap(a);
+    intersection_of(a, b);
+  }
+
+  void union_of(const interval_set &a, const interval_set &b) {
+    ceph_assert(&a != this);
+    ceph_assert(&b != this);
+    clear();
+    
+    //cout << "union_of" << endl;
+
+    // a
+    m = a.m;
+    _size = a._size;
+
+    // - (a*b)
+    interval_set ab;
+    ab.intersection_of(a, b);
+    subtract(ab);
+
+    // + b
+    insert(b);
+    return;
+  }
+  void union_of(const interval_set &b) {
+    interval_set a;
+    swap(a);    
+    union_of(a, b);
+  }
+  void union_insert(T off, T len) {
+    interval_set a;
+    a.insert(off, len);
+    union_of(a);
+  }
+
+  bool subset_of(const interval_set &big) const {
+    if (!size())
+      return true;
+    if (size() > big.size())
+      return false;
+    if (range_end() > big.range_end())
+      return false;
+
+    /*
+     * Use the lower_bound algorithm for larger size ratios
+     * where it performs better, but not for smaller size
+     * ratios where sequential search performs better.
+     */
+    if (big.size() / size() < 10)
+      return subset_size_sym(big);
+
+    for (const auto& [start, len] : m) {
+      if (!big.contains(start, len)) 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 interval_set &other, T start, T len) {
+    clear();
+    auto 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;
+      }
+    }
+  }
+
+  /*
+   * Move contents of m into another Map. Use that instead of
+   * encoding interval_set into bufferlist then decoding it back into Map.
+   */
+  Map detach() && {
+    return std::move(m);
+  }
+
+private:
+  // data
+  uint64_t _size = 0;
+  Map m;   // map start -> len
+};
+
+// declare traits explicitly because (1) it's templatized, and (2) we
+// want to include _nohead variants.
+template<typename T, template<typename, typename, typename ...> class C>
+struct denc_traits<interval_set<T, C>> {
+private:
+  using container_t = interval_set<T, C>;
+public:
+  static constexpr bool supported = true;
+  static constexpr bool bounded = false;
+  static constexpr bool featured = false;
+  static constexpr bool need_contiguous = denc_traits<T, C<T,T>>::need_contiguous;
+  static void bound_encode(const container_t& v, size_t& p) {
+    v.bound_encode(p);
+  }
+  static void encode(const container_t& v,
+		     ceph::buffer::list::contiguous_appender& p) {
+    v.encode(p);
+  }
+  static void decode(container_t& v, ceph::buffer::ptr::const_iterator& p) {
+    v.decode(p);
+  }
+  template<typename U=T>
+    static typename std::enable_if<sizeof(U) && !need_contiguous>::type
+  decode(container_t& v, ceph::buffer::list::iterator& p) {
+    v.decode(p);
+  }
+  static void encode_nohead(const container_t& v,
+			    ceph::buffer::list::contiguous_appender& p) {
+    v.encode_nohead(p);
+  }
+  static void decode_nohead(size_t n, container_t& v,
+			    ceph::buffer::ptr::const_iterator& p) {
+    v.decode_nohead(n, p);
+  }
+};
+
+
+template<typename T, template<typename, typename, typename ...> class C>
+inline std::ostream& operator<<(std::ostream& out, const interval_set<T,C> &s) {
+  out << "[";
+  bool first = true;
+  for (const auto& [start, len] : s) {
+    if (!first) out << ",";
+    out << start << "~" << len;
+    first = false;
+  }
+  out << "]";
+  return out;
+}
+
+
+#endif