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      1 #include "rxcpp/rx.hpp"
      2 
      3 #include "rxcpp/rx-test.hpp"
      4 #include "catch.hpp"
      5 
      6 #include <array>
      7 
      8 SCENARIO("ref_count other diamond sample"){
      9     printf("//! [ref_count other diamond sample]\n");
     10 
     11     /*
     12      * Implements the following diamond graph chain with publish+ref_count without using threads.
     13      * This version is composable because it does not use connect explicitly.
     14      *
     15      *            Values
     16      *          /      \
     17      *        *2        *100
     18      *          \      /
     19      *            Merge
     20      *             |
     21      *            RefCount
     22      */
     23 
     24     std::array<double, 5> a={{1.0, 2.0, 3.0, 4.0, 5.0}};
     25     auto values = rxcpp::observable<>::iterate(a)
     26         // The root of the chain is only subscribed to once.
     27         .tap([](double v) { printf("[0] OnNext: %lf\n", v); })
     28         .publish();
     29 
     30     auto values_to_long = values.map([](double v) { return (long) v; });
     31 
     32     // Left side multiplies by 2.
     33     auto left = values_to_long.map(
     34         [](long v) -> long {printf("[1] OnNext: %ld -> %ld\n", v, v*2); return v * 2L;} );
     35 
     36     // Right side multiplies by 100.
     37     auto right = values_to_long.map(
     38         [](long v) -> long {printf("[2] OnNext: %ld -> %ld\n", v, v*100); return v * 100L; });
     39 
     40     // Merge the left,right sides together.
     41     // The items are emitted interleaved ... [left1, right1, left2, right2, left3, right3, ...].
     42     auto merged = left.merge(right);
     43 
     44     // When this value is subscribed to, it calls connect on values.
     45     auto connect_on_subscribe = merged.ref_count(values);
     46 
     47     // This immediately starts emitting all values and blocks until they are completed.
     48     connect_on_subscribe.subscribe(
     49         [](long v) { printf("[3] OnNext: %ld\n", v); },
     50         [&]() { printf("[3] OnCompleted:\n"); });
     51 
     52     printf("//! [ref_count other diamond sample]\n");
     53 }
     54 
     55 // see also examples/doxygen/publish.cpp for non-ref_count diamonds
     56