Initial Commit - Lesson 31 (Commit #1)

Plugins/GameLiftServerSDK/ThirdParty/concurrentqueue/benchmarks/tbb/concurrent_hash_map.cpp

@@ -0,0 +1,58 @@
+/*
+    Copyright 2005-2014 Intel Corporation.  All Rights Reserved.
+
+    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
+    you can redistribute it and/or modify it under the terms of the GNU General Public License
+    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks is
+    distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
+    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+    See  the GNU General Public License for more details.   You should have received a copy of
+    the  GNU General Public License along with Threading Building Blocks; if not, write to the
+    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA
+
+    As a special exception,  you may use this file  as part of a free software library without
+    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
+    functions from this file, or you compile this file and link it with other files to produce
+    an executable,  this file does not by itself cause the resulting executable to be covered
+    by the GNU General Public License. This exception does not however invalidate any other
+    reasons why the executable file might be covered by the GNU General Public License.
+*/
+
+#include "tbb/concurrent_hash_map.h"
+
+namespace tbb {
+
+namespace internal {
+#if !TBB_NO_LEGACY
+struct hash_map_segment_base {
+    typedef spin_rw_mutex segment_mutex_t;
+    //! Type of a hash code.
+    typedef size_t hashcode_t;
+    //! Log2 of n_segment
+    static const size_t n_segment_bits = 6;
+    //! Maximum size of array of chains
+    static const size_t max_physical_size = size_t(1)<<(8*sizeof(hashcode_t)-n_segment_bits);
+    //! Mutex that protects this segment
+    segment_mutex_t my_mutex;
+    // Number of nodes
+    atomic<size_t> my_logical_size;
+    // Size of chains
+    /** Always zero or a power of two */
+    size_t my_physical_size;
+    //! True if my_logical_size>=my_physical_size.
+    /** Used to support Intel(R) Thread Checker. */
+    bool __TBB_EXPORTED_METHOD internal_grow_predicate() const;
+};
+
+bool hash_map_segment_base::internal_grow_predicate() const {
+    // Intel(R) Thread Checker considers the following reads to be races, so we hide them in the 
+    // library so that Intel(R) Thread Checker will ignore them.  The reads are used in a double-check
+    // context, so the program is nonetheless correct despite the race.
+    return my_logical_size >= my_physical_size && my_physical_size < max_physical_size;
+}
+#endif//!TBB_NO_LEGACY
+
+} // namespace internal
+
+} // namespace tbb
+