merge(3p/immer): Subtree merge at 'ad3e3556d' as 'third_party/immer'

Change-Id: I9636a41ad44b4218293833fd3e9456d9b07c731b

third_party/immer/extra/fuzzer/map.cpp

@@ -0,0 +1,85 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#include "fuzzer_input.hpp"
+
+#include <immer/map.hpp>
+
+#include <array>
+
+extern "C" int LLVMFuzzerTestOneInput(const std::uint8_t* data,
+                                      std::size_t size)
+{
+    constexpr auto var_count = 4;
+
+    using map_t = immer::map<char, int>;
+
+    auto vars = std::array<map_t, var_count>{};
+
+    auto is_valid_var = [&](auto idx) { return idx >= 0 && idx < var_count; };
+
+    return fuzzer_input{data, size}.run([&](auto& in) {
+        enum ops
+        {
+            op_set,
+            op_erase,
+            op_set_move,
+            op_erase_move,
+            op_iterate,
+            op_find,
+            op_update
+        };
+        auto src = read<char>(in, is_valid_var);
+        auto dst = read<char>(in, is_valid_var);
+        switch (read<char>(in)) {
+        case op_set: {
+            auto value = read<size_t>(in);
+            vars[dst]  = vars[src].set(value, 42);
+            break;
+        }
+        case op_erase: {
+            auto value = read<size_t>(in);
+            vars[dst]  = vars[src].erase(value);
+            break;
+        }
+        case op_set_move: {
+            auto value = read<size_t>(in);
+            vars[dst]  = std::move(vars[src]).set(value, 42);
+            break;
+        }
+        case op_erase_move: {
+            auto value = read<size_t>(in);
+            vars[dst]  = std::move(vars[src]).erase(value);
+            break;
+        }
+        case op_iterate: {
+            auto srcv = vars[src];
+            for (const auto& v : srcv) {
+                vars[dst] = vars[dst].set(v.first, v.second);
+            }
+            break;
+        }
+        case op_find: {
+            auto value = read<size_t>(in);
+            auto res   = vars[src].find(value);
+            if (res != nullptr) {
+                vars[dst] = vars[dst].set(*res, 42);
+            }
+            break;
+        }
+        case op_update: {
+            auto key  = read<size_t>(in);
+            vars[dst] = vars[src].update(key, [](int x) { return x + 1; });
+            break;
+        }
+        default:
+            break;
+        };
+        return true;
+    });
+}