1 files changed, 63 insertions, 0 deletions
diff --git a/src/mruset.h b/src/mruset.h
new file mode 100644
index 0000000000..0cf65853c4
--- /dev/null
+++ b/src/mruset.h
@@ -0,0 +1,63 @@
+// Copyright (c) 2012 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file license.txt or http://www.opensource.org/licenses/mit-license.php.
+#ifndef BITCOIN_MRUSET_H
+#define BITCOIN_MRUSET_H
+
+#include <set>
+#include <deque>
+
+template <typename T> class mruset
+{
+public:
+    typedef T key_type;
+    typedef T value_type;
+    typedef typename std::set<T>::iterator iterator;
+    typedef typename std::set<T>::const_iterator const_iterator;
+    typedef typename std::set<T>::size_type size_type;
+
+protected:
+    std::set<T> set;
+    std::deque<T> queue;
+    size_type nMaxSize;
+
+public:
+    mruset(size_type nMaxSizeIn = 0) { nMaxSize = nMaxSizeIn; }
+    iterator begin() const { return set.begin(); }
+    iterator end() const { return set.end(); }
+    size_type size() const { return set.size(); }
+    bool empty() const { return set.empty(); }
+    iterator find(const key_type& k) const { return set.find(k); }
+    size_type count(const key_type& k) const { return set.count(k); }
+    bool inline friend operator==(const mruset<T>& a, const mruset<T>& b) { return a.set == b.set; }
+    bool inline friend operator==(const mruset<T>& a, const std::set<T>& b) { return a.set == b; }
+    bool inline friend operator<(const mruset<T>& a, const mruset<T>& b) { return a.set < b.set; }
+    std::pair<iterator, bool> insert(const key_type& x)
+    {
+        std::pair<iterator, bool> ret = set.insert(x);
+        if (ret.second)
+        {
+            if (nMaxSize && queue.size() == nMaxSize)
+            {
+                set.erase(queue.front());
+                queue.pop_front();
+            }
+            queue.push_back(x);
+        }
+        return ret;
+    }
+    size_type max_size() const { return nMaxSize; }
+    size_type max_size(size_type s)
+    {
+        if (s)
+            while (queue.size() >= s)
+            {
+                set.erase(queue.front());
+                queue.pop_front();
+            }
+        nMaxSize = s;
+        return nMaxSize;
+    }
+};
+
+#endif