Initial commit from sysy-main

antlr/antlr4-runtime-4.13.2/runtime/src/FlatHashSet.h

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+// Copyright 2012-2022 The ANTLR Project
+//
+// Redistribution and use in source and binary forms, with or without modification, are permitted
+// provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of conditions
+//    and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list of
+//    conditions and the following disclaimer in the documentation and/or other materials provided
+//    with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be used to
+//    endorse or promote products derived from this software without specific prior written
+//    permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
+// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+// FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
+// WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include "antlr4-common.h"
+
+#if ANTLR4CPP_USING_ABSEIL
+#include "absl/container/flat_hash_set.h"
+#else
+#include <unordered_set>
+#endif
+
+// By default ANTLRv4 uses containers provided by the C++ standard library. In most deployments this
+// is fine, however in some using custom containers may be preferred. This header allows that by
+// optionally supporting some alternative implementations and allowing for more easier patching of
+// other alternatives.
+
+namespace antlr4 {
+
+#if ANTLR4CPP_USING_ABSEIL
+  template <typename Key,
+            typename Hash = typename absl::flat_hash_set<Key>::hasher,
+            typename Equal = typename absl::flat_hash_set<Key>::key_equal,
+            typename Allocator = typename absl::flat_hash_set<Key>::allocator_type>
+  using FlatHashSet = absl::flat_hash_set<Key, Hash, Equal, Allocator>;
+#else
+  template <typename Key,
+            typename Hash = std::hash<Key>,
+            typename Equal = std::equal_to<Key>,
+            typename Allocator = std::allocator<Key>>
+  using FlatHashSet = std::unordered_set<Key, Hash, Equal, Allocator>;
+#endif
+
+} // namespace antlr4