Initial import of libdpf.

Co-authored-by: Cursor <cursoragent@cursor.com>

thirdparty/json/docs/examples/json_pointer__back.cpp

@@ -0,0 +1,15 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // different JSON Pointers
+    json::json_pointer ptr1("/foo");
+    json::json_pointer ptr2("/foo/0");
+
+    // call empty()
+    std::cout << "last reference token of \"" << ptr1 << "\" is \"" << ptr1.back() << "\"\n"
+              << "last reference token of \"" << ptr2 << "\" is \"" << ptr2.back() << "\"" << std::endl;
+}