1 files changed, 48 insertions, 0 deletions
diff --git a/src/common.hpp b/src/common.hpp
index d3aca257..1971faa9 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -348,4 +348,52 @@ auto end (reversion_wrapper<T> w) { return w.iterable.rend(); }
 template <typename T>
 reversion_wrapper<T> reverse (T&& iterable) { return { iterable }; }
 
+
+template<typename T>
+struct RunIterable {
+    const ::std::vector<T>& list;
+    unsigned int ofs;
+    ::std::pair<size_t,size_t> cur;
+    RunIterable(const ::std::vector<T>& list):
+        list(list), ofs(0)
+    {
+        advance();
+    }
+    void advance() {
+        if( ofs < list.size() )
+        {
+            auto start = ofs;
+            while(ofs < list.size() && list[ofs] == list[start])
+                ofs ++;
+            cur = ::std::make_pair(start, ofs-1);
+        }
+        else
+        {
+            ofs = list.size()+1;
+        }
+    }
+    RunIterable<T> begin() { return *this; }
+    RunIterable<T> end() { auto rv = *this; rv.ofs = list.size()+1; return rv; }
+    bool operator==(const RunIterable<T>& x) {
+        return x.ofs == ofs;
+    }
+    bool operator!=(const RunIterable<T>& x) {
+        return !(*this == x);
+    }
+    void operator++() {
+        advance();
+    }
+    const ::std::pair<size_t,size_t>& operator*() const {
+        return this->cur;
+    }
+    const ::std::pair<size_t,size_t>* operator->() const {
+        return &this->cur;
+    }
+};
+template<typename T>
+RunIterable<T> runs(const ::std::vector<T>& x) {
+    return RunIterable<T>(x);
+}
+
+
 #endif