| /* |
| Copyright 2005-2010 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 |
| |
