feat add rxcpp

3party/cpplinq/linq_last.hpp

@@ -0,0 +1,85 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if !defined(CPPLINQ_LINQ_LAST_HPP)
+#define CPPLINQ_LINQ_LAST_HPP
+#pragma once
+
+namespace cpplinq { 
+
+    template <class Cursor>
+    typename Cursor::element_type
+        linq_last_(Cursor c, onepass_cursor_tag)
+    {
+        if (c.empty()) { throw std::logic_error("last() out of bounds"); }
+        typename Cursor::element_type elem = c.get();
+        for(;;) {
+            c.inc();
+            if (c.empty()) break;
+            elem = c.get();
+        }
+        return elem;
+    }
+
+    // TODO: bidirectional iterator in constant time
+
+    template <class Cursor>
+    typename Cursor::reference_type
+        linq_last_(Cursor c, forward_cursor_tag)
+    {
+        if (c.empty()) { throw std::logic_error("last() out of bounds"); }
+        Cursor best = c;
+        for(;;) {
+            c.inc();
+            if (c.empty()) break;
+            best = c;
+        }
+        return best.get();
+    }
+
+    template <class Cursor>
+    typename Cursor::reference_type
+        linq_last_(Cursor c, random_access_cursor_tag)
+    {
+        if (c.empty()) { throw std::logic_error("last() out of bounds"); }
+        c.skip(c.size()-1);
+        return c.get();
+    }
+
+    template <class Cursor>
+    typename Cursor::element_type
+        linq_last_or_default_(Cursor c, onepass_cursor_tag)
+    {
+        typename Cursor::element_type elem;
+        while(!c.empty()) {
+            elem = c.get();
+            c.inc();
+        }
+        return elem;
+    }
+
+    template <class Cursor>
+    typename Cursor::element_type
+        linq_last_or_default_(Cursor c, forward_cursor_tag)
+    {
+        if (c.empty()) { throw std::logic_error("last() out of bounds"); }
+        Cursor best = c;
+        for(;;) {
+            c.inc();
+            if (c.empty()) break;
+            best = c;
+        }
+        return best.get();
+    }
+
+    template <class Cursor>
+    typename Cursor::element_type
+        linq_last_or_default_(Cursor c, random_access_cursor_tag)
+    {
+        if (c.empty()) { return typename Cursor::element_type(); }
+        c.skip(c.size()-1);
+        return c.get();
+    }
+
+}
+
+#endif // CPPLINQ_LINQ_LAST_HPP