diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt
index c894cc85d9fca6ae9ce0818b8cf9858acb3aa381..b55aa2e17e1eac98f0afd0ff54cb2aedab11feac 100644
--- a/indra/llcommon/CMakeLists.txt
+++ b/indra/llcommon/CMakeLists.txt
@@ -222,6 +222,7 @@ set(llcommon_HEADER_FILES
llsdutil.h
llsimplehash.h
llsingleton.h
+ llsortedvector.h
llstacktrace.h
llstl.h
llstreamqueue.h
diff --git a/indra/llcommon/llsortedvector.h b/indra/llcommon/llsortedvector.h
new file mode 100644
index 0000000000000000000000000000000000000000..bb779e5192a68326dfb6d233ea17ef0eac0cdb78
--- /dev/null
+++ b/indra/llcommon/llsortedvector.h
@@ -0,0 +1,162 @@
+/**
+ * @file llsortedvector.h
+ * @author Nat Goodspeed
+ * @date 2012-04-08
+ * @brief LLSortedVector class wraps a vector that we maintain in sorted
+ * order so we can perform binary-search lookups.
+ *
+ * $LicenseInfo:firstyear=2012&license=viewerlgpl$
+ * Copyright (c) 2012, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+#if ! defined(LL_LLSORTEDVECTOR_H)
+#define LL_LLSORTEDVECTOR_H
+
+#include <vector>
+#include <algorithm>
+
+/**
+ * LLSortedVector contains a std::vector<std::pair> that we keep sorted on the
+ * first of the pair. This makes insertion somewhat more expensive than simple
+ * std::vector::push_back(), but allows us to use binary search for lookups.
+ * It's intended for small aggregates where lookup is far more performance-
+ * critical than insertion; in such cases a binary search on a small, sorted
+ * std::vector can be more performant than a std::map lookup.
+ */
+template <typename KEY, typename VALUE>
+class LLSortedVector
+{
+public:
+ typedef LLSortedVector<KEY, VALUE> self;
+ typedef KEY key_type;
+ typedef VALUE mapped_type;
+ typedef std::pair<key_type, mapped_type> value_type;
+ typedef std::vector<value_type> PairVector;
+ typedef typename PairVector::iterator iterator;
+ typedef typename PairVector::const_iterator const_iterator;
+
+ /// Empty
+ LLSortedVector() {}
+
+ /// Fixed initial size
+ LLSortedVector(std::size_t size):
+ mVector(size)
+ {}
+
+ /// Bulk load
+ template <typename ITER>
+ LLSortedVector(ITER begin, ITER end):
+ mVector(begin, end)
+ {
+ // Allow caller to dump in a bunch of (pairs convertible to)
+ // value_type if desired, but make sure we sort afterwards.
+ std::sort(mVector.begin(), mVector.end());
+ }
+
+ /// insert(key, value)
+ std::pair<iterator, bool> insert(const key_type& key, const mapped_type& value)
+ {
+ return insert(value_type(key, value));
+ }
+
+ /// insert(value_type)
+ std::pair<iterator, bool> insert(const value_type& pair)
+ {
+ typedef std::pair<iterator, bool> iterbool;
+ iterator found = std::lower_bound(mVector.begin(), mVector.end(), pair,
+ less<value_type>());
+ // have to check for end() before it's even valid to dereference
+ if (found == mVector.end())
+ {
+ std::size_t index(mVector.size());
+ mVector.push_back(pair);
+ // don't forget that push_back() invalidates 'found'
+ return iterbool(mVector.begin() + index, true);
+ }
+ if (found->first == pair.first)
+ {
+ return iterbool(found, false);
+ }
+ // remember that insert() invalidates 'found' -- save index
+ std::size_t index(found - mVector.begin());
+ mVector.insert(found, pair);
+ // okay, convert from index back to iterator
+ return iterbool(mVector.begin() + index, true);
+ }
+
+ iterator begin() { return mVector.begin(); }
+ iterator end() { return mVector.end(); }
+ const_iterator begin() const { return mVector.begin(); }
+ const_iterator end() const { return mVector.end(); }
+
+ bool empty() const { return mVector.empty(); }
+ std::size_t size() const { return mVector.size(); }
+
+ /// find
+ iterator find(const key_type& key)
+ {
+ iterator found = std::lower_bound(mVector.begin(), mVector.end(),
+ value_type(key, mapped_type()),
+ less<value_type>());
+ if (found == mVector.end() || found->first != key)
+ return mVector.end();
+ return found;
+ }
+
+ const_iterator find(const key_type& key) const
+ {
+ return const_cast<self*>(this)->find(key);
+ }
+
+ //For easy insertion shorthand. Eases std::map => LLSortedVector drop-in replacement.
+ mapped_type& operator[] (const key_type& key)
+ {
+ return insert(std::make_pair(key,mapped_type())).first->second;
+ }
+ const mapped_type& operator[] (const key_type& key) const
+ {
+ return insert(std::make_pair(key,mapped_type())).first->second;
+ }
+
+private:
+ // Define our own 'less' comparator so we can specialize without messing
+ // with std::less.
+ template <typename T>
+ struct less: public std::less<T> {};
+
+ // Specialize 'less' for an LLSortedVector::value_type involving
+ // std::type_info*. This is one of LLSortedVector's foremost use cases. We
+ // specialize 'less' rather than just defining a specific comparator
+ // because LLSortedVector should be usable for other key_types as well.
+ template <typename T>
+ struct less< std::pair<std::type_info*, T> >:
+ public std::binary_function<std::pair<std::type_info*, T>,
+ std::pair<std::type_info*, T>,
+ bool>
+ {
+ bool operator()(const std::pair<std::type_info*, T>& lhs,
+ const std::pair<std::type_info*, T>& rhs) const
+ {
+ return lhs.first->before(*rhs.first);
+ }
+ };
+
+ // Same as above, but with const std::type_info*.
+ template <typename T>
+ struct less< std::pair<const std::type_info*, T> >:
+ public std::binary_function<std::pair<const std::type_info*, T>,
+ std::pair<const std::type_info*, T>,
+ bool>
+ {
+ bool operator()(const std::pair<const std::type_info*, T>& lhs,
+ const std::pair<const std::type_info*, T>& rhs) const
+ {
+ return lhs.first->before(*rhs.first);
+ }
+ };
+
+ PairVector mVector;
+};
+
+#endif /* ! defined(LL_LLSORTEDVECTOR_H) */